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1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 **********************************************************************
5 *   Copyright (C) 1998-2016, International Business Machines
6 *   Corporation and others.  All Rights Reserved.
7 **********************************************************************
8 *
9 * File unistr.h
10 *
11 * Modification History:
12 *
13 *   Date        Name        Description
14 *   09/25/98    stephen     Creation.
15 *   11/11/98    stephen     Changed per 11/9 code review.
16 *   04/20/99    stephen     Overhauled per 4/16 code review.
17 *   11/18/99    aliu        Made to inherit from Replaceable.  Added method
18 *                           handleReplaceBetween(); other methods unchanged.
19 *   06/25/01    grhoten     Remove dependency on iostream.
20 ******************************************************************************
21 */
22 
23 #ifndef UNISTR_H
24 #define UNISTR_H
25 
26 /**
27  * \file
28  * \brief C++ API: Unicode String
29  */
30 
31 #include "unicode/utypes.h"
32 #include "unicode/rep.h"
33 #include "unicode/std_string.h"
34 #include "unicode/stringpiece.h"
35 #include "unicode/bytestream.h"
36 #include "unicode/ucasemap.h"
37 
38 struct UConverter;          // unicode/ucnv.h
39 
40 #ifndef U_COMPARE_CODE_POINT_ORDER
41 /* see also ustring.h and unorm.h */
42 /**
43  * Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc:
44  * Compare strings in code point order instead of code unit order.
45  * @stable ICU 2.2
46  */
47 #define U_COMPARE_CODE_POINT_ORDER  0x8000
48 #endif
49 
50 #ifndef USTRING_H
51 /**
52  * \ingroup ustring_ustrlen
53  */
54 U_STABLE int32_t U_EXPORT2
55 u_strlen(const UChar *s);
56 #endif
57 
58 /**
59  * \def U_STRING_CASE_MAPPER_DEFINED
60  * @internal
61  */
62 #ifndef U_STRING_CASE_MAPPER_DEFINED
63 #define U_STRING_CASE_MAPPER_DEFINED
64 
65 /**
66  * Internal string case mapping function type.
67  * @internal
68  */
69 typedef int32_t U_CALLCONV
70 UStringCaseMapper(const UCaseMap *csm,
71                   UChar *dest, int32_t destCapacity,
72                   const UChar *src, int32_t srcLength,
73                   UErrorCode *pErrorCode);
74 
75 #endif
76 
77 U_NAMESPACE_BEGIN
78 
79 #if !UCONFIG_NO_BREAK_ITERATION
80 class BreakIterator;        // unicode/brkiter.h
81 #endif
82 class Locale;               // unicode/locid.h
83 class StringCharacterIterator;
84 class UnicodeStringAppendable;  // unicode/appendable.h
85 
86 /* The <iostream> include has been moved to unicode/ustream.h */
87 
88 /**
89  * Constant to be used in the UnicodeString(char *, int32_t, EInvariant) constructor
90  * which constructs a Unicode string from an invariant-character char * string.
91  * About invariant characters see utypes.h.
92  * This constructor has no runtime dependency on conversion code and is
93  * therefore recommended over ones taking a charset name string
94  * (where the empty string "" indicates invariant-character conversion).
95  *
96  * @stable ICU 3.2
97  */
98 #define US_INV icu::UnicodeString::kInvariant
99 
100 /**
101  * Unicode String literals in C++.
102  * Dependent on the platform properties, different UnicodeString
103  * constructors should be used to create a UnicodeString object from
104  * a string literal.
105  * The macros are defined for maximum performance.
106  * They work only for strings that contain "invariant characters", i.e.,
107  * only latin letters, digits, and some punctuation.
108  * See utypes.h for details.
109  *
110  * The string parameter must be a C string literal.
111  * The length of the string, not including the terminating
112  * <code>NUL</code>, must be specified as a constant.
113  * The U_STRING_DECL macro should be invoked exactly once for one
114  * such string variable before it is used.
115  * @stable ICU 2.0
116  */
117 #if defined(U_DECLARE_UTF16)
118 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)U_DECLARE_UTF16(cs), _length)
119 #elif U_SIZEOF_WCHAR_T==U_SIZEOF_UCHAR && (U_CHARSET_FAMILY==U_ASCII_FAMILY || (U_SIZEOF_UCHAR == 2 && defined(U_WCHAR_IS_UTF16)))
120 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)L ## cs, _length)
121 #elif U_SIZEOF_UCHAR==1 && U_CHARSET_FAMILY==U_ASCII_FAMILY
122 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(TRUE, (const UChar *)cs, _length)
123 #else
124 #   define UNICODE_STRING(cs, _length) icu::UnicodeString(cs, _length, US_INV)
125 #endif
126 
127 /**
128  * Unicode String literals in C++.
129  * Dependent on the platform properties, different UnicodeString
130  * constructors should be used to create a UnicodeString object from
131  * a string literal.
132  * The macros are defined for improved performance.
133  * They work only for strings that contain "invariant characters", i.e.,
134  * only latin letters, digits, and some punctuation.
135  * See utypes.h for details.
136  *
137  * The string parameter must be a C string literal.
138  * @stable ICU 2.0
139  */
140 #define UNICODE_STRING_SIMPLE(cs) UNICODE_STRING(cs, -1)
141 
142 /**
143  * \def UNISTR_FROM_CHAR_EXPLICIT
144  * This can be defined to be empty or "explicit".
145  * If explicit, then the UnicodeString(UChar) and UnicodeString(UChar32)
146  * constructors are marked as explicit, preventing their inadvertent use.
147  * @stable ICU 49
148  */
149 #ifndef UNISTR_FROM_CHAR_EXPLICIT
150 # if defined(U_COMBINED_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) || defined(U_I18N_IMPLEMENTATION) || defined(U_IO_IMPLEMENTATION)
151     // Auto-"explicit" in ICU library code.
152 #   define UNISTR_FROM_CHAR_EXPLICIT explicit
153 # else
154     // Empty by default for source code compatibility.
155 #   define UNISTR_FROM_CHAR_EXPLICIT
156 # endif
157 #endif
158 
159 /**
160  * \def UNISTR_FROM_STRING_EXPLICIT
161  * This can be defined to be empty or "explicit".
162  * If explicit, then the UnicodeString(const char *) and UnicodeString(const UChar *)
163  * constructors are marked as explicit, preventing their inadvertent use.
164  *
165  * In particular, this helps prevent accidentally depending on ICU conversion code
166  * by passing a string literal into an API with a const UnicodeString & parameter.
167  * @stable ICU 49
168  */
169 #ifndef UNISTR_FROM_STRING_EXPLICIT
170 # if defined(U_COMBINED_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) || defined(U_I18N_IMPLEMENTATION) || defined(U_IO_IMPLEMENTATION)
171     // Auto-"explicit" in ICU library code.
172 #   define UNISTR_FROM_STRING_EXPLICIT explicit
173 # else
174     // Empty by default for source code compatibility.
175 #   define UNISTR_FROM_STRING_EXPLICIT
176 # endif
177 #endif
178 
179 /**
180  * \def UNISTR_OBJECT_SIZE
181  * Desired sizeof(UnicodeString) in bytes.
182  * It should be a multiple of sizeof(pointer) to avoid unusable space for padding.
183  * The object size may want to be a multiple of 16 bytes,
184  * which is a common granularity for heap allocation.
185  *
186  * Any space inside the object beyond sizeof(vtable pointer) + 2
187  * is available for storing short strings inside the object.
188  * The bigger the object, the longer a string that can be stored inside the object,
189  * without additional heap allocation.
190  *
191  * Depending on a platform's pointer size, pointer alignment requirements,
192  * and struct padding, the compiler will usually round up sizeof(UnicodeString)
193  * to 4 * sizeof(pointer) (or 3 * sizeof(pointer) for P128 data models),
194  * to hold the fields for heap-allocated strings.
195  * Such a minimum size also ensures that the object is easily large enough
196  * to hold at least 2 UChars, for one supplementary code point (U16_MAX_LENGTH).
197  *
198  * sizeof(UnicodeString) >= 48 should work for all known platforms.
199  *
200  * For example, on a 64-bit machine where sizeof(vtable pointer) is 8,
201  * sizeof(UnicodeString) = 64 would leave space for
202  * (64 - sizeof(vtable pointer) - 2) / U_SIZEOF_UCHAR = (64 - 8 - 2) / 2 = 27
203  * UChars stored inside the object.
204  *
205  * The minimum object size on a 64-bit machine would be
206  * 4 * sizeof(pointer) = 4 * 8 = 32 bytes,
207  * and the internal buffer would hold up to 11 UChars in that case.
208  *
209  * @see U16_MAX_LENGTH
210  * @stable ICU 56
211  */
212 #ifndef UNISTR_OBJECT_SIZE
213 # define UNISTR_OBJECT_SIZE 64
214 #endif
215 
216 /**
217  * UnicodeString is a string class that stores Unicode characters directly and provides
218  * similar functionality as the Java String and StringBuffer/StringBuilder classes.
219  * It is a concrete implementation of the abstract class Replaceable (for transliteration).
220  *
221  * A UnicodeString may also "alias" an external array of characters
222  * (that is, point to it, rather than own the array)
223  * whose lifetime must then at least match the lifetime of the aliasing object.
224  * This aliasing may be preserved when returning a UnicodeString by value,
225  * depending on the compiler and the function implementation,
226  * via Return Value Optimization (RVO) or the move assignment operator.
227  * (However, the copy assignment operator does not preserve aliasing.)
228  * For details see the description of storage models at the end of the class API docs
229  * and in the User Guide chapter linked from there.
230  *
231  * The UnicodeString class is not suitable for subclassing.
232  *
233  * <p>For an overview of Unicode strings in C and C++ see the
234  * <a href="http://userguide.icu-project.org/strings#TOC-Strings-in-C-C-">User Guide Strings chapter</a>.</p>
235  *
236  * <p>In ICU, a Unicode string consists of 16-bit Unicode <em>code units</em>.
237  * A Unicode character may be stored with either one code unit
238  * (the most common case) or with a matched pair of special code units
239  * ("surrogates"). The data type for code units is UChar.
240  * For single-character handling, a Unicode character code <em>point</em> is a value
241  * in the range 0..0x10ffff. ICU uses the UChar32 type for code points.</p>
242  *
243  * <p>Indexes and offsets into and lengths of strings always count code units, not code points.
244  * This is the same as with multi-byte char* strings in traditional string handling.
245  * Operations on partial strings typically do not test for code point boundaries.
246  * If necessary, the user needs to take care of such boundaries by testing for the code unit
247  * values or by using functions like
248  * UnicodeString::getChar32Start() and UnicodeString::getChar32Limit()
249  * (or, in C, the equivalent macros U16_SET_CP_START() and U16_SET_CP_LIMIT(), see utf.h).</p>
250  *
251  * UnicodeString methods are more lenient with regard to input parameter values
252  * than other ICU APIs. In particular:
253  * - If indexes are out of bounds for a UnicodeString object
254  *   (<0 or >length()) then they are "pinned" to the nearest boundary.
255  * - If primitive string pointer values (e.g., const UChar * or char *)
256  *   for input strings are NULL, then those input string parameters are treated
257  *   as if they pointed to an empty string.
258  *   However, this is <em>not</em> the case for char * parameters for charset names
259  *   or other IDs.
260  * - Most UnicodeString methods do not take a UErrorCode parameter because
261  *   there are usually very few opportunities for failure other than a shortage
262  *   of memory, error codes in low-level C++ string methods would be inconvenient,
263  *   and the error code as the last parameter (ICU convention) would prevent
264  *   the use of default parameter values.
265  *   Instead, such methods set the UnicodeString into a "bogus" state
266  *   (see isBogus()) if an error occurs.
267  *
268  * In string comparisons, two UnicodeString objects that are both "bogus"
269  * compare equal (to be transitive and prevent endless loops in sorting),
270  * and a "bogus" string compares less than any non-"bogus" one.
271  *
272  * Const UnicodeString methods are thread-safe. Multiple threads can use
273  * const methods on the same UnicodeString object simultaneously,
274  * but non-const methods must not be called concurrently (in multiple threads)
275  * with any other (const or non-const) methods.
276  *
277  * Similarly, const UnicodeString & parameters are thread-safe.
278  * One object may be passed in as such a parameter concurrently in multiple threads.
279  * This includes the const UnicodeString & parameters for
280  * copy construction, assignment, and cloning.
281  *
282  * <p>UnicodeString uses several storage methods.
283  * String contents can be stored inside the UnicodeString object itself,
284  * in an allocated and shared buffer, or in an outside buffer that is "aliased".
285  * Most of this is done transparently, but careful aliasing in particular provides
286  * significant performance improvements.
287  * Also, the internal buffer is accessible via special functions.
288  * For details see the
289  * <a href="http://userguide.icu-project.org/strings#TOC-Maximizing-Performance-with-the-UnicodeString-Storage-Model">User Guide Strings chapter</a>.</p>
290  *
291  * @see utf.h
292  * @see CharacterIterator
293  * @stable ICU 2.0
294  */
295 class U_COMMON_API UnicodeString : public Replaceable
296 {
297 public:
298 
299   /**
300    * Constant to be used in the UnicodeString(char *, int32_t, EInvariant) constructor
301    * which constructs a Unicode string from an invariant-character char * string.
302    * Use the macro US_INV instead of the full qualification for this value.
303    *
304    * @see US_INV
305    * @stable ICU 3.2
306    */
307   enum EInvariant {
308     /**
309      * @see EInvariant
310      * @stable ICU 3.2
311      */
312     kInvariant
313   };
314 
315   //========================================
316   // Read-only operations
317   //========================================
318 
319   /* Comparison - bitwise only - for international comparison use collation */
320 
321   /**
322    * Equality operator. Performs only bitwise comparison.
323    * @param text The UnicodeString to compare to this one.
324    * @return TRUE if <TT>text</TT> contains the same characters as this one,
325    * FALSE otherwise.
326    * @stable ICU 2.0
327    */
328   inline UBool operator== (const UnicodeString& text) const;
329 
330   /**
331    * Inequality operator. Performs only bitwise comparison.
332    * @param text The UnicodeString to compare to this one.
333    * @return FALSE if <TT>text</TT> contains the same characters as this one,
334    * TRUE otherwise.
335    * @stable ICU 2.0
336    */
337   inline UBool operator!= (const UnicodeString& text) const;
338 
339   /**
340    * Greater than operator. Performs only bitwise comparison.
341    * @param text The UnicodeString to compare to this one.
342    * @return TRUE if the characters in this are bitwise
343    * greater than the characters in <code>text</code>, FALSE otherwise
344    * @stable ICU 2.0
345    */
346   inline UBool operator> (const UnicodeString& text) const;
347 
348   /**
349    * Less than operator. Performs only bitwise comparison.
350    * @param text The UnicodeString to compare to this one.
351    * @return TRUE if the characters in this are bitwise
352    * less than the characters in <code>text</code>, FALSE otherwise
353    * @stable ICU 2.0
354    */
355   inline UBool operator< (const UnicodeString& text) const;
356 
357   /**
358    * Greater than or equal operator. Performs only bitwise comparison.
359    * @param text The UnicodeString to compare to this one.
360    * @return TRUE if the characters in this are bitwise
361    * greater than or equal to the characters in <code>text</code>, FALSE otherwise
362    * @stable ICU 2.0
363    */
364   inline UBool operator>= (const UnicodeString& text) const;
365 
366   /**
367    * Less than or equal operator. Performs only bitwise comparison.
368    * @param text The UnicodeString to compare to this one.
369    * @return TRUE if the characters in this are bitwise
370    * less than or equal to the characters in <code>text</code>, FALSE otherwise
371    * @stable ICU 2.0
372    */
373   inline UBool operator<= (const UnicodeString& text) const;
374 
375   /**
376    * Compare the characters bitwise in this UnicodeString to
377    * the characters in <code>text</code>.
378    * @param text The UnicodeString to compare to this one.
379    * @return The result of bitwise character comparison: 0 if this
380    * contains the same characters as <code>text</code>, -1 if the characters in
381    * this are bitwise less than the characters in <code>text</code>, +1 if the
382    * characters in this are bitwise greater than the characters
383    * in <code>text</code>.
384    * @stable ICU 2.0
385    */
386   inline int8_t compare(const UnicodeString& text) const;
387 
388   /**
389    * Compare the characters bitwise in the range
390    * [<TT>start</TT>, <TT>start + length</TT>) with the characters
391    * in the <b>entire string</b> <TT>text</TT>.
392    * (The parameters "start" and "length" are not applied to the other text "text".)
393    * @param start the offset at which the compare operation begins
394    * @param length the number of characters of text to compare.
395    * @param text the other text to be compared against this string.
396    * @return The result of bitwise character comparison: 0 if this
397    * contains the same characters as <code>text</code>, -1 if the characters in
398    * this are bitwise less than the characters in <code>text</code>, +1 if the
399    * characters in this are bitwise greater than the characters
400    * in <code>text</code>.
401    * @stable ICU 2.0
402    */
403   inline int8_t compare(int32_t start,
404          int32_t length,
405          const UnicodeString& text) const;
406 
407   /**
408    * Compare the characters bitwise in the range
409    * [<TT>start</TT>, <TT>start + length</TT>) with the characters
410    * in <TT>srcText</TT> in the range
411    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
412    * @param start the offset at which the compare operation begins
413    * @param length the number of characters in this to compare.
414    * @param srcText the text to be compared
415    * @param srcStart the offset into <TT>srcText</TT> to start comparison
416    * @param srcLength the number of characters in <TT>src</TT> to compare
417    * @return The result of bitwise character comparison: 0 if this
418    * contains the same characters as <code>srcText</code>, -1 if the characters in
419    * this are bitwise less than the characters in <code>srcText</code>, +1 if the
420    * characters in this are bitwise greater than the characters
421    * in <code>srcText</code>.
422    * @stable ICU 2.0
423    */
424    inline int8_t compare(int32_t start,
425          int32_t length,
426          const UnicodeString& srcText,
427          int32_t srcStart,
428          int32_t srcLength) const;
429 
430   /**
431    * Compare the characters bitwise in this UnicodeString with the first
432    * <TT>srcLength</TT> characters in <TT>srcChars</TT>.
433    * @param srcChars The characters to compare to this UnicodeString.
434    * @param srcLength the number of characters in <TT>srcChars</TT> to compare
435    * @return The result of bitwise character comparison: 0 if this
436    * contains the same characters as <code>srcChars</code>, -1 if the characters in
437    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the
438    * characters in this are bitwise greater than the characters
439    * in <code>srcChars</code>.
440    * @stable ICU 2.0
441    */
442   inline int8_t compare(const UChar *srcChars,
443          int32_t srcLength) const;
444 
445   /**
446    * Compare the characters bitwise in the range
447    * [<TT>start</TT>, <TT>start + length</TT>) with the first
448    * <TT>length</TT> characters in <TT>srcChars</TT>
449    * @param start the offset at which the compare operation begins
450    * @param length the number of characters to compare.
451    * @param srcChars the characters to be compared
452    * @return The result of bitwise character comparison: 0 if this
453    * contains the same characters as <code>srcChars</code>, -1 if the characters in
454    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the
455    * characters in this are bitwise greater than the characters
456    * in <code>srcChars</code>.
457    * @stable ICU 2.0
458    */
459   inline int8_t compare(int32_t start,
460          int32_t length,
461          const UChar *srcChars) const;
462 
463   /**
464    * Compare the characters bitwise in the range
465    * [<TT>start</TT>, <TT>start + length</TT>) with the characters
466    * in <TT>srcChars</TT> in the range
467    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
468    * @param start the offset at which the compare operation begins
469    * @param length the number of characters in this to compare
470    * @param srcChars the characters to be compared
471    * @param srcStart the offset into <TT>srcChars</TT> to start comparison
472    * @param srcLength the number of characters in <TT>srcChars</TT> to compare
473    * @return The result of bitwise character comparison: 0 if this
474    * contains the same characters as <code>srcChars</code>, -1 if the characters in
475    * this are bitwise less than the characters in <code>srcChars</code>, +1 if the
476    * characters in this are bitwise greater than the characters
477    * in <code>srcChars</code>.
478    * @stable ICU 2.0
479    */
480   inline int8_t compare(int32_t start,
481          int32_t length,
482          const UChar *srcChars,
483          int32_t srcStart,
484          int32_t srcLength) const;
485 
486   /**
487    * Compare the characters bitwise in the range
488    * [<TT>start</TT>, <TT>limit</TT>) with the characters
489    * in <TT>srcText</TT> in the range
490    * [<TT>srcStart</TT>, <TT>srcLimit</TT>).
491    * @param start the offset at which the compare operation begins
492    * @param limit the offset immediately following the compare operation
493    * @param srcText the text to be compared
494    * @param srcStart the offset into <TT>srcText</TT> to start comparison
495    * @param srcLimit the offset into <TT>srcText</TT> to limit comparison
496    * @return The result of bitwise character comparison: 0 if this
497    * contains the same characters as <code>srcText</code>, -1 if the characters in
498    * this are bitwise less than the characters in <code>srcText</code>, +1 if the
499    * characters in this are bitwise greater than the characters
500    * in <code>srcText</code>.
501    * @stable ICU 2.0
502    */
503   inline int8_t compareBetween(int32_t start,
504             int32_t limit,
505             const UnicodeString& srcText,
506             int32_t srcStart,
507             int32_t srcLimit) const;
508 
509   /**
510    * Compare two Unicode strings in code point order.
511    * The result may be different from the results of compare(), operator<, etc.
512    * if supplementary characters are present:
513    *
514    * In UTF-16, supplementary characters (with code points U+10000 and above) are
515    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
516    * which means that they compare as less than some other BMP characters like U+feff.
517    * This function compares Unicode strings in code point order.
518    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
519    *
520    * @param text Another string to compare this one to.
521    * @return a negative/zero/positive integer corresponding to whether
522    * this string is less than/equal to/greater than the second one
523    * in code point order
524    * @stable ICU 2.0
525    */
526   inline int8_t compareCodePointOrder(const UnicodeString& text) const;
527 
528   /**
529    * Compare two Unicode strings in code point order.
530    * The result may be different from the results of compare(), operator<, etc.
531    * if supplementary characters are present:
532    *
533    * In UTF-16, supplementary characters (with code points U+10000 and above) are
534    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
535    * which means that they compare as less than some other BMP characters like U+feff.
536    * This function compares Unicode strings in code point order.
537    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
538    *
539    * @param start The start offset in this string at which the compare operation begins.
540    * @param length The number of code units from this string to compare.
541    * @param srcText Another string to compare this one to.
542    * @return a negative/zero/positive integer corresponding to whether
543    * this string is less than/equal to/greater than the second one
544    * in code point order
545    * @stable ICU 2.0
546    */
547   inline int8_t compareCodePointOrder(int32_t start,
548                                       int32_t length,
549                                       const UnicodeString& srcText) const;
550 
551   /**
552    * Compare two Unicode strings in code point order.
553    * The result may be different from the results of compare(), operator<, etc.
554    * if supplementary characters are present:
555    *
556    * In UTF-16, supplementary characters (with code points U+10000 and above) are
557    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
558    * which means that they compare as less than some other BMP characters like U+feff.
559    * This function compares Unicode strings in code point order.
560    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
561    *
562    * @param start The start offset in this string at which the compare operation begins.
563    * @param length The number of code units from this string to compare.
564    * @param srcText Another string to compare this one to.
565    * @param srcStart The start offset in that string at which the compare operation begins.
566    * @param srcLength The number of code units from that string to compare.
567    * @return a negative/zero/positive integer corresponding to whether
568    * this string is less than/equal to/greater than the second one
569    * in code point order
570    * @stable ICU 2.0
571    */
572    inline int8_t compareCodePointOrder(int32_t start,
573                                        int32_t length,
574                                        const UnicodeString& srcText,
575                                        int32_t srcStart,
576                                        int32_t srcLength) const;
577 
578   /**
579    * Compare two Unicode strings in code point order.
580    * The result may be different from the results of compare(), operator<, etc.
581    * if supplementary characters are present:
582    *
583    * In UTF-16, supplementary characters (with code points U+10000 and above) are
584    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
585    * which means that they compare as less than some other BMP characters like U+feff.
586    * This function compares Unicode strings in code point order.
587    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
588    *
589    * @param srcChars A pointer to another string to compare this one to.
590    * @param srcLength The number of code units from that string to compare.
591    * @return a negative/zero/positive integer corresponding to whether
592    * this string is less than/equal to/greater than the second one
593    * in code point order
594    * @stable ICU 2.0
595    */
596   inline int8_t compareCodePointOrder(const UChar *srcChars,
597                                       int32_t srcLength) const;
598 
599   /**
600    * Compare two Unicode strings in code point order.
601    * The result may be different from the results of compare(), operator<, etc.
602    * if supplementary characters are present:
603    *
604    * In UTF-16, supplementary characters (with code points U+10000 and above) are
605    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
606    * which means that they compare as less than some other BMP characters like U+feff.
607    * This function compares Unicode strings in code point order.
608    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
609    *
610    * @param start The start offset in this string at which the compare operation begins.
611    * @param length The number of code units from this string to compare.
612    * @param srcChars A pointer to another string to compare this one to.
613    * @return a negative/zero/positive integer corresponding to whether
614    * this string is less than/equal to/greater than the second one
615    * in code point order
616    * @stable ICU 2.0
617    */
618   inline int8_t compareCodePointOrder(int32_t start,
619                                       int32_t length,
620                                       const UChar *srcChars) const;
621 
622   /**
623    * Compare two Unicode strings in code point order.
624    * The result may be different from the results of compare(), operator<, etc.
625    * if supplementary characters are present:
626    *
627    * In UTF-16, supplementary characters (with code points U+10000 and above) are
628    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
629    * which means that they compare as less than some other BMP characters like U+feff.
630    * This function compares Unicode strings in code point order.
631    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
632    *
633    * @param start The start offset in this string at which the compare operation begins.
634    * @param length The number of code units from this string to compare.
635    * @param srcChars A pointer to another string to compare this one to.
636    * @param srcStart The start offset in that string at which the compare operation begins.
637    * @param srcLength The number of code units from that string to compare.
638    * @return a negative/zero/positive integer corresponding to whether
639    * this string is less than/equal to/greater than the second one
640    * in code point order
641    * @stable ICU 2.0
642    */
643   inline int8_t compareCodePointOrder(int32_t start,
644                                       int32_t length,
645                                       const UChar *srcChars,
646                                       int32_t srcStart,
647                                       int32_t srcLength) const;
648 
649   /**
650    * Compare two Unicode strings in code point order.
651    * The result may be different from the results of compare(), operator<, etc.
652    * if supplementary characters are present:
653    *
654    * In UTF-16, supplementary characters (with code points U+10000 and above) are
655    * stored with pairs of surrogate code units. These have values from 0xd800 to 0xdfff,
656    * which means that they compare as less than some other BMP characters like U+feff.
657    * This function compares Unicode strings in code point order.
658    * If either of the UTF-16 strings is malformed (i.e., it contains unpaired surrogates), then the result is not defined.
659    *
660    * @param start The start offset in this string at which the compare operation begins.
661    * @param limit The offset after the last code unit from this string to compare.
662    * @param srcText Another string to compare this one to.
663    * @param srcStart The start offset in that string at which the compare operation begins.
664    * @param srcLimit The offset after the last code unit from that string to compare.
665    * @return a negative/zero/positive integer corresponding to whether
666    * this string is less than/equal to/greater than the second one
667    * in code point order
668    * @stable ICU 2.0
669    */
670   inline int8_t compareCodePointOrderBetween(int32_t start,
671                                              int32_t limit,
672                                              const UnicodeString& srcText,
673                                              int32_t srcStart,
674                                              int32_t srcLimit) const;
675 
676   /**
677    * Compare two strings case-insensitively using full case folding.
678    * This is equivalent to this->foldCase(options).compare(text.foldCase(options)).
679    *
680    * @param text Another string to compare this one to.
681    * @param options A bit set of options:
682    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
683    *     Comparison in code unit order with default case folding.
684    *
685    *   - U_COMPARE_CODE_POINT_ORDER
686    *     Set to choose code point order instead of code unit order
687    *     (see u_strCompare for details).
688    *
689    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
690    *
691    * @return A negative, zero, or positive integer indicating the comparison result.
692    * @stable ICU 2.0
693    */
694   inline int8_t caseCompare(const UnicodeString& text, uint32_t options) const;
695 
696   /**
697    * Compare two strings case-insensitively using full case folding.
698    * This is equivalent to this->foldCase(options).compare(srcText.foldCase(options)).
699    *
700    * @param start The start offset in this string at which the compare operation begins.
701    * @param length The number of code units from this string to compare.
702    * @param srcText Another string to compare this one to.
703    * @param options A bit set of options:
704    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
705    *     Comparison in code unit order with default case folding.
706    *
707    *   - U_COMPARE_CODE_POINT_ORDER
708    *     Set to choose code point order instead of code unit order
709    *     (see u_strCompare for details).
710    *
711    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
712    *
713    * @return A negative, zero, or positive integer indicating the comparison result.
714    * @stable ICU 2.0
715    */
716   inline int8_t caseCompare(int32_t start,
717          int32_t length,
718          const UnicodeString& srcText,
719          uint32_t options) const;
720 
721   /**
722    * Compare two strings case-insensitively using full case folding.
723    * This is equivalent to this->foldCase(options).compare(srcText.foldCase(options)).
724    *
725    * @param start The start offset in this string at which the compare operation begins.
726    * @param length The number of code units from this string to compare.
727    * @param srcText Another string to compare this one to.
728    * @param srcStart The start offset in that string at which the compare operation begins.
729    * @param srcLength The number of code units from that string to compare.
730    * @param options A bit set of options:
731    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
732    *     Comparison in code unit order with default case folding.
733    *
734    *   - U_COMPARE_CODE_POINT_ORDER
735    *     Set to choose code point order instead of code unit order
736    *     (see u_strCompare for details).
737    *
738    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
739    *
740    * @return A negative, zero, or positive integer indicating the comparison result.
741    * @stable ICU 2.0
742    */
743   inline int8_t caseCompare(int32_t start,
744          int32_t length,
745          const UnicodeString& srcText,
746          int32_t srcStart,
747          int32_t srcLength,
748          uint32_t options) const;
749 
750   /**
751    * Compare two strings case-insensitively using full case folding.
752    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).
753    *
754    * @param srcChars A pointer to another string to compare this one to.
755    * @param srcLength The number of code units from that string to compare.
756    * @param options A bit set of options:
757    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
758    *     Comparison in code unit order with default case folding.
759    *
760    *   - U_COMPARE_CODE_POINT_ORDER
761    *     Set to choose code point order instead of code unit order
762    *     (see u_strCompare for details).
763    *
764    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
765    *
766    * @return A negative, zero, or positive integer indicating the comparison result.
767    * @stable ICU 2.0
768    */
769   inline int8_t caseCompare(const UChar *srcChars,
770          int32_t srcLength,
771          uint32_t options) const;
772 
773   /**
774    * Compare two strings case-insensitively using full case folding.
775    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).
776    *
777    * @param start The start offset in this string at which the compare operation begins.
778    * @param length The number of code units from this string to compare.
779    * @param srcChars A pointer to another string to compare this one to.
780    * @param options A bit set of options:
781    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
782    *     Comparison in code unit order with default case folding.
783    *
784    *   - U_COMPARE_CODE_POINT_ORDER
785    *     Set to choose code point order instead of code unit order
786    *     (see u_strCompare for details).
787    *
788    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
789    *
790    * @return A negative, zero, or positive integer indicating the comparison result.
791    * @stable ICU 2.0
792    */
793   inline int8_t caseCompare(int32_t start,
794          int32_t length,
795          const UChar *srcChars,
796          uint32_t options) const;
797 
798   /**
799    * Compare two strings case-insensitively using full case folding.
800    * This is equivalent to this->foldCase(options).compare(srcChars.foldCase(options)).
801    *
802    * @param start The start offset in this string at which the compare operation begins.
803    * @param length The number of code units from this string to compare.
804    * @param srcChars A pointer to another string to compare this one to.
805    * @param srcStart The start offset in that string at which the compare operation begins.
806    * @param srcLength The number of code units from that string to compare.
807    * @param options A bit set of options:
808    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
809    *     Comparison in code unit order with default case folding.
810    *
811    *   - U_COMPARE_CODE_POINT_ORDER
812    *     Set to choose code point order instead of code unit order
813    *     (see u_strCompare for details).
814    *
815    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
816    *
817    * @return A negative, zero, or positive integer indicating the comparison result.
818    * @stable ICU 2.0
819    */
820   inline int8_t caseCompare(int32_t start,
821          int32_t length,
822          const UChar *srcChars,
823          int32_t srcStart,
824          int32_t srcLength,
825          uint32_t options) const;
826 
827   /**
828    * Compare two strings case-insensitively using full case folding.
829    * This is equivalent to this->foldCase(options).compareBetween(text.foldCase(options)).
830    *
831    * @param start The start offset in this string at which the compare operation begins.
832    * @param limit The offset after the last code unit from this string to compare.
833    * @param srcText Another string to compare this one to.
834    * @param srcStart The start offset in that string at which the compare operation begins.
835    * @param srcLimit The offset after the last code unit from that string to compare.
836    * @param options A bit set of options:
837    *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
838    *     Comparison in code unit order with default case folding.
839    *
840    *   - U_COMPARE_CODE_POINT_ORDER
841    *     Set to choose code point order instead of code unit order
842    *     (see u_strCompare for details).
843    *
844    *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
845    *
846    * @return A negative, zero, or positive integer indicating the comparison result.
847    * @stable ICU 2.0
848    */
849   inline int8_t caseCompareBetween(int32_t start,
850             int32_t limit,
851             const UnicodeString& srcText,
852             int32_t srcStart,
853             int32_t srcLimit,
854             uint32_t options) const;
855 
856   /**
857    * Determine if this starts with the characters in <TT>text</TT>
858    * @param text The text to match.
859    * @return TRUE if this starts with the characters in <TT>text</TT>,
860    * FALSE otherwise
861    * @stable ICU 2.0
862    */
863   inline UBool startsWith(const UnicodeString& text) const;
864 
865   /**
866    * Determine if this starts with the characters in <TT>srcText</TT>
867    * in the range [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
868    * @param srcText The text to match.
869    * @param srcStart the offset into <TT>srcText</TT> to start matching
870    * @param srcLength the number of characters in <TT>srcText</TT> to match
871    * @return TRUE if this starts with the characters in <TT>text</TT>,
872    * FALSE otherwise
873    * @stable ICU 2.0
874    */
875   inline UBool startsWith(const UnicodeString& srcText,
876             int32_t srcStart,
877             int32_t srcLength) const;
878 
879   /**
880    * Determine if this starts with the characters in <TT>srcChars</TT>
881    * @param srcChars The characters to match.
882    * @param srcLength the number of characters in <TT>srcChars</TT>
883    * @return TRUE if this starts with the characters in <TT>srcChars</TT>,
884    * FALSE otherwise
885    * @stable ICU 2.0
886    */
887   inline UBool startsWith(const UChar *srcChars,
888             int32_t srcLength) const;
889 
890   /**
891    * Determine if this ends with the characters in <TT>srcChars</TT>
892    * in the range  [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
893    * @param srcChars The characters to match.
894    * @param srcStart the offset into <TT>srcText</TT> to start matching
895    * @param srcLength the number of characters in <TT>srcChars</TT> to match
896    * @return TRUE if this ends with the characters in <TT>srcChars</TT>, FALSE otherwise
897    * @stable ICU 2.0
898    */
899   inline UBool startsWith(const UChar *srcChars,
900             int32_t srcStart,
901             int32_t srcLength) const;
902 
903   /**
904    * Determine if this ends with the characters in <TT>text</TT>
905    * @param text The text to match.
906    * @return TRUE if this ends with the characters in <TT>text</TT>,
907    * FALSE otherwise
908    * @stable ICU 2.0
909    */
910   inline UBool endsWith(const UnicodeString& text) const;
911 
912   /**
913    * Determine if this ends with the characters in <TT>srcText</TT>
914    * in the range [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
915    * @param srcText The text to match.
916    * @param srcStart the offset into <TT>srcText</TT> to start matching
917    * @param srcLength the number of characters in <TT>srcText</TT> to match
918    * @return TRUE if this ends with the characters in <TT>text</TT>,
919    * FALSE otherwise
920    * @stable ICU 2.0
921    */
922   inline UBool endsWith(const UnicodeString& srcText,
923           int32_t srcStart,
924           int32_t srcLength) const;
925 
926   /**
927    * Determine if this ends with the characters in <TT>srcChars</TT>
928    * @param srcChars The characters to match.
929    * @param srcLength the number of characters in <TT>srcChars</TT>
930    * @return TRUE if this ends with the characters in <TT>srcChars</TT>,
931    * FALSE otherwise
932    * @stable ICU 2.0
933    */
934   inline UBool endsWith(const UChar *srcChars,
935           int32_t srcLength) const;
936 
937   /**
938    * Determine if this ends with the characters in <TT>srcChars</TT>
939    * in the range  [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
940    * @param srcChars The characters to match.
941    * @param srcStart the offset into <TT>srcText</TT> to start matching
942    * @param srcLength the number of characters in <TT>srcChars</TT> to match
943    * @return TRUE if this ends with the characters in <TT>srcChars</TT>,
944    * FALSE otherwise
945    * @stable ICU 2.0
946    */
947   inline UBool endsWith(const UChar *srcChars,
948           int32_t srcStart,
949           int32_t srcLength) const;
950 
951 
952   /* Searching - bitwise only */
953 
954   /**
955    * Locate in this the first occurrence of the characters in <TT>text</TT>,
956    * using bitwise comparison.
957    * @param text The text to search for.
958    * @return The offset into this of the start of <TT>text</TT>,
959    * or -1 if not found.
960    * @stable ICU 2.0
961    */
962   inline int32_t indexOf(const UnicodeString& text) const;
963 
964   /**
965    * Locate in this the first occurrence of the characters in <TT>text</TT>
966    * starting at offset <TT>start</TT>, using bitwise comparison.
967    * @param text The text to search for.
968    * @param start The offset at which searching will start.
969    * @return The offset into this of the start of <TT>text</TT>,
970    * or -1 if not found.
971    * @stable ICU 2.0
972    */
973   inline int32_t indexOf(const UnicodeString& text,
974               int32_t start) const;
975 
976   /**
977    * Locate in this the first occurrence in the range
978    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
979    * in <TT>text</TT>, using bitwise comparison.
980    * @param text The text to search for.
981    * @param start The offset at which searching will start.
982    * @param length The number of characters to search
983    * @return The offset into this of the start of <TT>text</TT>,
984    * or -1 if not found.
985    * @stable ICU 2.0
986    */
987   inline int32_t indexOf(const UnicodeString& text,
988               int32_t start,
989               int32_t length) const;
990 
991   /**
992    * Locate in this the first occurrence in the range
993    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
994    *  in <TT>srcText</TT> in the range
995    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),
996    * using bitwise comparison.
997    * @param srcText The text to search for.
998    * @param srcStart the offset into <TT>srcText</TT> at which
999    * to start matching
1000    * @param srcLength the number of characters in <TT>srcText</TT> to match
1001    * @param start the offset into this at which to start matching
1002    * @param length the number of characters in this to search
1003    * @return The offset into this of the start of <TT>text</TT>,
1004    * or -1 if not found.
1005    * @stable ICU 2.0
1006    */
1007   inline int32_t indexOf(const UnicodeString& srcText,
1008               int32_t srcStart,
1009               int32_t srcLength,
1010               int32_t start,
1011               int32_t length) const;
1012 
1013   /**
1014    * Locate in this the first occurrence of the characters in
1015    * <TT>srcChars</TT>
1016    * starting at offset <TT>start</TT>, using bitwise comparison.
1017    * @param srcChars The text to search for.
1018    * @param srcLength the number of characters in <TT>srcChars</TT> to match
1019    * @param start the offset into this at which to start matching
1020    * @return The offset into this of the start of <TT>text</TT>,
1021    * or -1 if not found.
1022    * @stable ICU 2.0
1023    */
1024   inline int32_t indexOf(const UChar *srcChars,
1025               int32_t srcLength,
1026               int32_t start) const;
1027 
1028   /**
1029    * Locate in this the first occurrence in the range
1030    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1031    * in <TT>srcChars</TT>, using bitwise comparison.
1032    * @param srcChars The text to search for.
1033    * @param srcLength the number of characters in <TT>srcChars</TT>
1034    * @param start The offset at which searching will start.
1035    * @param length The number of characters to search
1036    * @return The offset into this of the start of <TT>srcChars</TT>,
1037    * or -1 if not found.
1038    * @stable ICU 2.0
1039    */
1040   inline int32_t indexOf(const UChar *srcChars,
1041               int32_t srcLength,
1042               int32_t start,
1043               int32_t length) const;
1044 
1045   /**
1046    * Locate in this the first occurrence in the range
1047    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1048    * in <TT>srcChars</TT> in the range
1049    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),
1050    * using bitwise comparison.
1051    * @param srcChars The text to search for.
1052    * @param srcStart the offset into <TT>srcChars</TT> at which
1053    * to start matching
1054    * @param srcLength the number of characters in <TT>srcChars</TT> to match
1055    * @param start the offset into this at which to start matching
1056    * @param length the number of characters in this to search
1057    * @return The offset into this of the start of <TT>text</TT>,
1058    * or -1 if not found.
1059    * @stable ICU 2.0
1060    */
1061   int32_t indexOf(const UChar *srcChars,
1062               int32_t srcStart,
1063               int32_t srcLength,
1064               int32_t start,
1065               int32_t length) const;
1066 
1067   /**
1068    * Locate in this the first occurrence of the BMP code point <code>c</code>,
1069    * using bitwise comparison.
1070    * @param c The code unit to search for.
1071    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1072    * @stable ICU 2.0
1073    */
1074   inline int32_t indexOf(UChar c) const;
1075 
1076   /**
1077    * Locate in this the first occurrence of the code point <TT>c</TT>,
1078    * using bitwise comparison.
1079    *
1080    * @param c The code point to search for.
1081    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1082    * @stable ICU 2.0
1083    */
1084   inline int32_t indexOf(UChar32 c) const;
1085 
1086   /**
1087    * Locate in this the first occurrence of the BMP code point <code>c</code>,
1088    * starting at offset <TT>start</TT>, using bitwise comparison.
1089    * @param c The code unit to search for.
1090    * @param start The offset at which searching will start.
1091    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1092    * @stable ICU 2.0
1093    */
1094   inline int32_t indexOf(UChar c,
1095               int32_t start) const;
1096 
1097   /**
1098    * Locate in this the first occurrence of the code point <TT>c</TT>
1099    * starting at offset <TT>start</TT>, using bitwise comparison.
1100    *
1101    * @param c The code point to search for.
1102    * @param start The offset at which searching will start.
1103    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1104    * @stable ICU 2.0
1105    */
1106   inline int32_t indexOf(UChar32 c,
1107               int32_t start) const;
1108 
1109   /**
1110    * Locate in this the first occurrence of the BMP code point <code>c</code>
1111    * in the range [<TT>start</TT>, <TT>start + length</TT>),
1112    * using bitwise comparison.
1113    * @param c The code unit to search for.
1114    * @param start the offset into this at which to start matching
1115    * @param length the number of characters in this to search
1116    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1117    * @stable ICU 2.0
1118    */
1119   inline int32_t indexOf(UChar c,
1120               int32_t start,
1121               int32_t length) const;
1122 
1123   /**
1124    * Locate in this the first occurrence of the code point <TT>c</TT>
1125    * in the range [<TT>start</TT>, <TT>start + length</TT>),
1126    * using bitwise comparison.
1127    *
1128    * @param c The code point to search for.
1129    * @param start the offset into this at which to start matching
1130    * @param length the number of characters in this to search
1131    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1132    * @stable ICU 2.0
1133    */
1134   inline int32_t indexOf(UChar32 c,
1135               int32_t start,
1136               int32_t length) const;
1137 
1138   /**
1139    * Locate in this the last occurrence of the characters in <TT>text</TT>,
1140    * using bitwise comparison.
1141    * @param text The text to search for.
1142    * @return The offset into this of the start of <TT>text</TT>,
1143    * or -1 if not found.
1144    * @stable ICU 2.0
1145    */
1146   inline int32_t lastIndexOf(const UnicodeString& text) const;
1147 
1148   /**
1149    * Locate in this the last occurrence of the characters in <TT>text</TT>
1150    * starting at offset <TT>start</TT>, using bitwise comparison.
1151    * @param text The text to search for.
1152    * @param start The offset at which searching will start.
1153    * @return The offset into this of the start of <TT>text</TT>,
1154    * or -1 if not found.
1155    * @stable ICU 2.0
1156    */
1157   inline int32_t lastIndexOf(const UnicodeString& text,
1158               int32_t start) const;
1159 
1160   /**
1161    * Locate in this the last occurrence in the range
1162    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1163    * in <TT>text</TT>, using bitwise comparison.
1164    * @param text The text to search for.
1165    * @param start The offset at which searching will start.
1166    * @param length The number of characters to search
1167    * @return The offset into this of the start of <TT>text</TT>,
1168    * or -1 if not found.
1169    * @stable ICU 2.0
1170    */
1171   inline int32_t lastIndexOf(const UnicodeString& text,
1172               int32_t start,
1173               int32_t length) const;
1174 
1175   /**
1176    * Locate in this the last occurrence in the range
1177    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1178    * in <TT>srcText</TT> in the range
1179    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),
1180    * using bitwise comparison.
1181    * @param srcText The text to search for.
1182    * @param srcStart the offset into <TT>srcText</TT> at which
1183    * to start matching
1184    * @param srcLength the number of characters in <TT>srcText</TT> to match
1185    * @param start the offset into this at which to start matching
1186    * @param length the number of characters in this to search
1187    * @return The offset into this of the start of <TT>text</TT>,
1188    * or -1 if not found.
1189    * @stable ICU 2.0
1190    */
1191   inline int32_t lastIndexOf(const UnicodeString& srcText,
1192               int32_t srcStart,
1193               int32_t srcLength,
1194               int32_t start,
1195               int32_t length) const;
1196 
1197   /**
1198    * Locate in this the last occurrence of the characters in <TT>srcChars</TT>
1199    * starting at offset <TT>start</TT>, using bitwise comparison.
1200    * @param srcChars The text to search for.
1201    * @param srcLength the number of characters in <TT>srcChars</TT> to match
1202    * @param start the offset into this at which to start matching
1203    * @return The offset into this of the start of <TT>text</TT>,
1204    * or -1 if not found.
1205    * @stable ICU 2.0
1206    */
1207   inline int32_t lastIndexOf(const UChar *srcChars,
1208               int32_t srcLength,
1209               int32_t start) const;
1210 
1211   /**
1212    * Locate in this the last occurrence in the range
1213    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1214    * in <TT>srcChars</TT>, using bitwise comparison.
1215    * @param srcChars The text to search for.
1216    * @param srcLength the number of characters in <TT>srcChars</TT>
1217    * @param start The offset at which searching will start.
1218    * @param length The number of characters to search
1219    * @return The offset into this of the start of <TT>srcChars</TT>,
1220    * or -1 if not found.
1221    * @stable ICU 2.0
1222    */
1223   inline int32_t lastIndexOf(const UChar *srcChars,
1224               int32_t srcLength,
1225               int32_t start,
1226               int32_t length) const;
1227 
1228   /**
1229    * Locate in this the last occurrence in the range
1230    * [<TT>start</TT>, <TT>start + length</TT>) of the characters
1231    * in <TT>srcChars</TT> in the range
1232    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>),
1233    * using bitwise comparison.
1234    * @param srcChars The text to search for.
1235    * @param srcStart the offset into <TT>srcChars</TT> at which
1236    * to start matching
1237    * @param srcLength the number of characters in <TT>srcChars</TT> to match
1238    * @param start the offset into this at which to start matching
1239    * @param length the number of characters in this to search
1240    * @return The offset into this of the start of <TT>text</TT>,
1241    * or -1 if not found.
1242    * @stable ICU 2.0
1243    */
1244   int32_t lastIndexOf(const UChar *srcChars,
1245               int32_t srcStart,
1246               int32_t srcLength,
1247               int32_t start,
1248               int32_t length) const;
1249 
1250   /**
1251    * Locate in this the last occurrence of the BMP code point <code>c</code>,
1252    * using bitwise comparison.
1253    * @param c The code unit to search for.
1254    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1255    * @stable ICU 2.0
1256    */
1257   inline int32_t lastIndexOf(UChar c) const;
1258 
1259   /**
1260    * Locate in this the last occurrence of the code point <TT>c</TT>,
1261    * using bitwise comparison.
1262    *
1263    * @param c The code point to search for.
1264    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1265    * @stable ICU 2.0
1266    */
1267   inline int32_t lastIndexOf(UChar32 c) const;
1268 
1269   /**
1270    * Locate in this the last occurrence of the BMP code point <code>c</code>
1271    * starting at offset <TT>start</TT>, using bitwise comparison.
1272    * @param c The code unit to search for.
1273    * @param start The offset at which searching will start.
1274    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1275    * @stable ICU 2.0
1276    */
1277   inline int32_t lastIndexOf(UChar c,
1278               int32_t start) const;
1279 
1280   /**
1281    * Locate in this the last occurrence of the code point <TT>c</TT>
1282    * starting at offset <TT>start</TT>, using bitwise comparison.
1283    *
1284    * @param c The code point to search for.
1285    * @param start The offset at which searching will start.
1286    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1287    * @stable ICU 2.0
1288    */
1289   inline int32_t lastIndexOf(UChar32 c,
1290               int32_t start) const;
1291 
1292   /**
1293    * Locate in this the last occurrence of the BMP code point <code>c</code>
1294    * in the range [<TT>start</TT>, <TT>start + length</TT>),
1295    * using bitwise comparison.
1296    * @param c The code unit to search for.
1297    * @param start the offset into this at which to start matching
1298    * @param length the number of characters in this to search
1299    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1300    * @stable ICU 2.0
1301    */
1302   inline int32_t lastIndexOf(UChar c,
1303               int32_t start,
1304               int32_t length) const;
1305 
1306   /**
1307    * Locate in this the last occurrence of the code point <TT>c</TT>
1308    * in the range [<TT>start</TT>, <TT>start + length</TT>),
1309    * using bitwise comparison.
1310    *
1311    * @param c The code point to search for.
1312    * @param start the offset into this at which to start matching
1313    * @param length the number of characters in this to search
1314    * @return The offset into this of <TT>c</TT>, or -1 if not found.
1315    * @stable ICU 2.0
1316    */
1317   inline int32_t lastIndexOf(UChar32 c,
1318               int32_t start,
1319               int32_t length) const;
1320 
1321 
1322   /* Character access */
1323 
1324   /**
1325    * Return the code unit at offset <tt>offset</tt>.
1326    * If the offset is not valid (0..length()-1) then U+ffff is returned.
1327    * @param offset a valid offset into the text
1328    * @return the code unit at offset <tt>offset</tt>
1329    *         or 0xffff if the offset is not valid for this string
1330    * @stable ICU 2.0
1331    */
1332   inline UChar charAt(int32_t offset) const;
1333 
1334   /**
1335    * Return the code unit at offset <tt>offset</tt>.
1336    * If the offset is not valid (0..length()-1) then U+ffff is returned.
1337    * @param offset a valid offset into the text
1338    * @return the code unit at offset <tt>offset</tt>
1339    * @stable ICU 2.0
1340    */
1341   inline UChar operator[] (int32_t offset) const;
1342 
1343   /**
1344    * Return the code point that contains the code unit
1345    * at offset <tt>offset</tt>.
1346    * If the offset is not valid (0..length()-1) then U+ffff is returned.
1347    * @param offset a valid offset into the text
1348    * that indicates the text offset of any of the code units
1349    * that will be assembled into a code point (21-bit value) and returned
1350    * @return the code point of text at <tt>offset</tt>
1351    *         or 0xffff if the offset is not valid for this string
1352    * @stable ICU 2.0
1353    */
1354   UChar32 char32At(int32_t offset) const;
1355 
1356   /**
1357    * Adjust a random-access offset so that
1358    * it points to the beginning of a Unicode character.
1359    * The offset that is passed in points to
1360    * any code unit of a code point,
1361    * while the returned offset will point to the first code unit
1362    * of the same code point.
1363    * In UTF-16, if the input offset points to a second surrogate
1364    * of a surrogate pair, then the returned offset will point
1365    * to the first surrogate.
1366    * @param offset a valid offset into one code point of the text
1367    * @return offset of the first code unit of the same code point
1368    * @see U16_SET_CP_START
1369    * @stable ICU 2.0
1370    */
1371   int32_t getChar32Start(int32_t offset) const;
1372 
1373   /**
1374    * Adjust a random-access offset so that
1375    * it points behind a Unicode character.
1376    * The offset that is passed in points behind
1377    * any code unit of a code point,
1378    * while the returned offset will point behind the last code unit
1379    * of the same code point.
1380    * In UTF-16, if the input offset points behind the first surrogate
1381    * (i.e., to the second surrogate)
1382    * of a surrogate pair, then the returned offset will point
1383    * behind the second surrogate (i.e., to the first surrogate).
1384    * @param offset a valid offset after any code unit of a code point of the text
1385    * @return offset of the first code unit after the same code point
1386    * @see U16_SET_CP_LIMIT
1387    * @stable ICU 2.0
1388    */
1389   int32_t getChar32Limit(int32_t offset) const;
1390 
1391   /**
1392    * Move the code unit index along the string by delta code points.
1393    * Interpret the input index as a code unit-based offset into the string,
1394    * move the index forward or backward by delta code points, and
1395    * return the resulting index.
1396    * The input index should point to the first code unit of a code point,
1397    * if there is more than one.
1398    *
1399    * Both input and output indexes are code unit-based as for all
1400    * string indexes/offsets in ICU (and other libraries, like MBCS char*).
1401    * If delta<0 then the index is moved backward (toward the start of the string).
1402    * If delta>0 then the index is moved forward (toward the end of the string).
1403    *
1404    * This behaves like CharacterIterator::move32(delta, kCurrent).
1405    *
1406    * Behavior for out-of-bounds indexes:
1407    * <code>moveIndex32</code> pins the input index to 0..length(), i.e.,
1408    * if the input index<0 then it is pinned to 0;
1409    * if it is index>length() then it is pinned to length().
1410    * Afterwards, the index is moved by <code>delta</code> code points
1411    * forward or backward,
1412    * but no further backward than to 0 and no further forward than to length().
1413    * The resulting index return value will be in between 0 and length(), inclusively.
1414    *
1415    * Examples:
1416    * <pre>
1417    * // s has code points 'a' U+10000 'b' U+10ffff U+2029
1418    * UnicodeString s=UNICODE_STRING("a\\U00010000b\\U0010ffff\\u2029", 31).unescape();
1419    *
1420    * // initial index: position of U+10000
1421    * int32_t index=1;
1422    *
1423    * // the following examples will all result in index==4, position of U+10ffff
1424    *
1425    * // skip 2 code points from some position in the string
1426    * index=s.moveIndex32(index, 2); // skips U+10000 and 'b'
1427    *
1428    * // go to the 3rd code point from the start of s (0-based)
1429    * index=s.moveIndex32(0, 3); // skips 'a', U+10000, and 'b'
1430    *
1431    * // go to the next-to-last code point of s
1432    * index=s.moveIndex32(s.length(), -2); // backward-skips U+2029 and U+10ffff
1433    * </pre>
1434    *
1435    * @param index input code unit index
1436    * @param delta (signed) code point count to move the index forward or backward
1437    *        in the string
1438    * @return the resulting code unit index
1439    * @stable ICU 2.0
1440    */
1441   int32_t moveIndex32(int32_t index, int32_t delta) const;
1442 
1443   /* Substring extraction */
1444 
1445   /**
1446    * Copy the characters in the range
1447    * [<tt>start</tt>, <tt>start + length</tt>) into the array <tt>dst</tt>,
1448    * beginning at <tt>dstStart</tt>.
1449    * If the string aliases to <code>dst</code> itself as an external buffer,
1450    * then extract() will not copy the contents.
1451    *
1452    * @param start offset of first character which will be copied into the array
1453    * @param length the number of characters to extract
1454    * @param dst array in which to copy characters.  The length of <tt>dst</tt>
1455    * must be at least (<tt>dstStart + length</tt>).
1456    * @param dstStart the offset in <TT>dst</TT> where the first character
1457    * will be extracted
1458    * @stable ICU 2.0
1459    */
1460   inline void extract(int32_t start,
1461            int32_t length,
1462            UChar *dst,
1463            int32_t dstStart = 0) const;
1464 
1465   /**
1466    * Copy the contents of the string into dest.
1467    * This is a convenience function that
1468    * checks if there is enough space in dest,
1469    * extracts the entire string if possible,
1470    * and NUL-terminates dest if possible.
1471    *
1472    * If the string fits into dest but cannot be NUL-terminated
1473    * (length()==destCapacity) then the error code is set to U_STRING_NOT_TERMINATED_WARNING.
1474    * If the string itself does not fit into dest
1475    * (length()>destCapacity) then the error code is set to U_BUFFER_OVERFLOW_ERROR.
1476    *
1477    * If the string aliases to <code>dest</code> itself as an external buffer,
1478    * then extract() will not copy the contents.
1479    *
1480    * @param dest Destination string buffer.
1481    * @param destCapacity Number of UChars available at dest.
1482    * @param errorCode ICU error code.
1483    * @return length()
1484    * @stable ICU 2.0
1485    */
1486   int32_t
1487   extract(UChar *dest, int32_t destCapacity,
1488           UErrorCode &errorCode) const;
1489 
1490   /**
1491    * Copy the characters in the range
1492    * [<tt>start</tt>, <tt>start + length</tt>) into the  UnicodeString
1493    * <tt>target</tt>.
1494    * @param start offset of first character which will be copied
1495    * @param length the number of characters to extract
1496    * @param target UnicodeString into which to copy characters.
1497    * @return A reference to <TT>target</TT>
1498    * @stable ICU 2.0
1499    */
1500   inline void extract(int32_t start,
1501            int32_t length,
1502            UnicodeString& target) const;
1503 
1504   /**
1505    * Copy the characters in the range [<tt>start</tt>, <tt>limit</tt>)
1506    * into the array <tt>dst</tt>, beginning at <tt>dstStart</tt>.
1507    * @param start offset of first character which will be copied into the array
1508    * @param limit offset immediately following the last character to be copied
1509    * @param dst array in which to copy characters.  The length of <tt>dst</tt>
1510    * must be at least (<tt>dstStart + (limit - start)</tt>).
1511    * @param dstStart the offset in <TT>dst</TT> where the first character
1512    * will be extracted
1513    * @stable ICU 2.0
1514    */
1515   inline void extractBetween(int32_t start,
1516               int32_t limit,
1517               UChar *dst,
1518               int32_t dstStart = 0) const;
1519 
1520   /**
1521    * Copy the characters in the range [<tt>start</tt>, <tt>limit</tt>)
1522    * into the UnicodeString <tt>target</tt>.  Replaceable API.
1523    * @param start offset of first character which will be copied
1524    * @param limit offset immediately following the last character to be copied
1525    * @param target UnicodeString into which to copy characters.
1526    * @return A reference to <TT>target</TT>
1527    * @stable ICU 2.0
1528    */
1529   virtual void extractBetween(int32_t start,
1530               int32_t limit,
1531               UnicodeString& target) const;
1532 
1533   /**
1534    * Copy the characters in the range
1535    * [<tt>start</TT>, <tt>start + startLength</TT>) into an array of characters.
1536    * All characters must be invariant (see utypes.h).
1537    * Use US_INV as the last, signature-distinguishing parameter.
1538    *
1539    * This function does not write any more than <code>targetCapacity</code>
1540    * characters but returns the length of the entire output string
1541    * so that one can allocate a larger buffer and call the function again
1542    * if necessary.
1543    * The output string is NUL-terminated if possible.
1544    *
1545    * @param start offset of first character which will be copied
1546    * @param startLength the number of characters to extract
1547    * @param target the target buffer for extraction, can be NULL
1548    *               if targetLength is 0
1549    * @param targetCapacity the length of the target buffer
1550    * @param inv Signature-distinguishing paramater, use US_INV.
1551    * @return the output string length, not including the terminating NUL
1552    * @stable ICU 3.2
1553    */
1554   int32_t extract(int32_t start,
1555            int32_t startLength,
1556            char *target,
1557            int32_t targetCapacity,
1558            enum EInvariant inv) const;
1559 
1560 #if U_CHARSET_IS_UTF8 || !UCONFIG_NO_CONVERSION
1561 
1562   /**
1563    * Copy the characters in the range
1564    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters
1565    * in the platform's default codepage.
1566    * This function does not write any more than <code>targetLength</code>
1567    * characters but returns the length of the entire output string
1568    * so that one can allocate a larger buffer and call the function again
1569    * if necessary.
1570    * The output string is NUL-terminated if possible.
1571    *
1572    * @param start offset of first character which will be copied
1573    * @param startLength the number of characters to extract
1574    * @param target the target buffer for extraction
1575    * @param targetLength the length of the target buffer
1576    * If <TT>target</TT> is NULL, then the number of bytes required for
1577    * <TT>target</TT> is returned.
1578    * @return the output string length, not including the terminating NUL
1579    * @stable ICU 2.0
1580    */
1581   int32_t extract(int32_t start,
1582            int32_t startLength,
1583            char *target,
1584            uint32_t targetLength) const;
1585 
1586 #endif
1587 
1588 #if !UCONFIG_NO_CONVERSION
1589 
1590   /**
1591    * Copy the characters in the range
1592    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters
1593    * in a specified codepage.
1594    * The output string is NUL-terminated.
1595    *
1596    * Recommendation: For invariant-character strings use
1597    * extract(int32_t start, int32_t length, char *target, int32_t targetCapacity, enum EInvariant inv) const
1598    * because it avoids object code dependencies of UnicodeString on
1599    * the conversion code.
1600    *
1601    * @param start offset of first character which will be copied
1602    * @param startLength the number of characters to extract
1603    * @param target the target buffer for extraction
1604    * @param codepage the desired codepage for the characters.  0 has
1605    * the special meaning of the default codepage
1606    * If <code>codepage</code> is an empty string (<code>""</code>),
1607    * then a simple conversion is performed on the codepage-invariant
1608    * subset ("invariant characters") of the platform encoding. See utypes.h.
1609    * If <TT>target</TT> is NULL, then the number of bytes required for
1610    * <TT>target</TT> is returned. It is assumed that the target is big enough
1611    * to fit all of the characters.
1612    * @return the output string length, not including the terminating NUL
1613    * @stable ICU 2.0
1614    */
1615   inline int32_t extract(int32_t start,
1616                  int32_t startLength,
1617                  char *target,
1618                  const char *codepage = 0) const;
1619 
1620   /**
1621    * Copy the characters in the range
1622    * [<tt>start</TT>, <tt>start + length</TT>) into an array of characters
1623    * in a specified codepage.
1624    * This function does not write any more than <code>targetLength</code>
1625    * characters but returns the length of the entire output string
1626    * so that one can allocate a larger buffer and call the function again
1627    * if necessary.
1628    * The output string is NUL-terminated if possible.
1629    *
1630    * Recommendation: For invariant-character strings use
1631    * extract(int32_t start, int32_t length, char *target, int32_t targetCapacity, enum EInvariant inv) const
1632    * because it avoids object code dependencies of UnicodeString on
1633    * the conversion code.
1634    *
1635    * @param start offset of first character which will be copied
1636    * @param startLength the number of characters to extract
1637    * @param target the target buffer for extraction
1638    * @param targetLength the length of the target buffer
1639    * @param codepage the desired codepage for the characters.  0 has
1640    * the special meaning of the default codepage
1641    * If <code>codepage</code> is an empty string (<code>""</code>),
1642    * then a simple conversion is performed on the codepage-invariant
1643    * subset ("invariant characters") of the platform encoding. See utypes.h.
1644    * If <TT>target</TT> is NULL, then the number of bytes required for
1645    * <TT>target</TT> is returned.
1646    * @return the output string length, not including the terminating NUL
1647    * @stable ICU 2.0
1648    */
1649   int32_t extract(int32_t start,
1650            int32_t startLength,
1651            char *target,
1652            uint32_t targetLength,
1653            const char *codepage) const;
1654 
1655   /**
1656    * Convert the UnicodeString into a codepage string using an existing UConverter.
1657    * The output string is NUL-terminated if possible.
1658    *
1659    * This function avoids the overhead of opening and closing a converter if
1660    * multiple strings are extracted.
1661    *
1662    * @param dest destination string buffer, can be NULL if destCapacity==0
1663    * @param destCapacity the number of chars available at dest
1664    * @param cnv the converter object to be used (ucnv_resetFromUnicode() will be called),
1665    *        or NULL for the default converter
1666    * @param errorCode normal ICU error code
1667    * @return the length of the output string, not counting the terminating NUL;
1668    *         if the length is greater than destCapacity, then the string will not fit
1669    *         and a buffer of the indicated length would need to be passed in
1670    * @stable ICU 2.0
1671    */
1672   int32_t extract(char *dest, int32_t destCapacity,
1673                   UConverter *cnv,
1674                   UErrorCode &errorCode) const;
1675 
1676 #endif
1677 
1678   /**
1679    * Create a temporary substring for the specified range.
1680    * Unlike the substring constructor and setTo() functions,
1681    * the object returned here will be a read-only alias (using getBuffer())
1682    * rather than copying the text.
1683    * As a result, this substring operation is much faster but requires
1684    * that the original string not be modified or deleted during the lifetime
1685    * of the returned substring object.
1686    * @param start offset of the first character visible in the substring
1687    * @param length length of the substring
1688    * @return a read-only alias UnicodeString object for the substring
1689    * @stable ICU 4.4
1690    */
1691   UnicodeString tempSubString(int32_t start=0, int32_t length=INT32_MAX) const;
1692 
1693   /**
1694    * Create a temporary substring for the specified range.
1695    * Same as tempSubString(start, length) except that the substring range
1696    * is specified as a (start, limit) pair (with an exclusive limit index)
1697    * rather than a (start, length) pair.
1698    * @param start offset of the first character visible in the substring
1699    * @param limit offset immediately following the last character visible in the substring
1700    * @return a read-only alias UnicodeString object for the substring
1701    * @stable ICU 4.4
1702    */
1703   inline UnicodeString tempSubStringBetween(int32_t start, int32_t limit=INT32_MAX) const;
1704 
1705   /**
1706    * Convert the UnicodeString to UTF-8 and write the result
1707    * to a ByteSink. This is called by toUTF8String().
1708    * Unpaired surrogates are replaced with U+FFFD.
1709    * Calls u_strToUTF8WithSub().
1710    *
1711    * @param sink A ByteSink to which the UTF-8 version of the string is written.
1712    *             sink.Flush() is called at the end.
1713    * @stable ICU 4.2
1714    * @see toUTF8String
1715    */
1716   void toUTF8(ByteSink &sink) const;
1717 
1718 #if U_HAVE_STD_STRING
1719 
1720   /**
1721    * Convert the UnicodeString to UTF-8 and append the result
1722    * to a standard string.
1723    * Unpaired surrogates are replaced with U+FFFD.
1724    * Calls toUTF8().
1725    *
1726    * @param result A standard string (or a compatible object)
1727    *        to which the UTF-8 version of the string is appended.
1728    * @return The string object.
1729    * @stable ICU 4.2
1730    * @see toUTF8
1731    */
1732   template<typename StringClass>
toUTF8String(StringClass & result)1733   StringClass &toUTF8String(StringClass &result) const {
1734     StringByteSink<StringClass> sbs(&result);
1735     toUTF8(sbs);
1736     return result;
1737   }
1738 
1739 #endif
1740 
1741   /**
1742    * Convert the UnicodeString to UTF-32.
1743    * Unpaired surrogates are replaced with U+FFFD.
1744    * Calls u_strToUTF32WithSub().
1745    *
1746    * @param utf32 destination string buffer, can be NULL if capacity==0
1747    * @param capacity the number of UChar32s available at utf32
1748    * @param errorCode Standard ICU error code. Its input value must
1749    *                  pass the U_SUCCESS() test, or else the function returns
1750    *                  immediately. Check for U_FAILURE() on output or use with
1751    *                  function chaining. (See User Guide for details.)
1752    * @return The length of the UTF-32 string.
1753    * @see fromUTF32
1754    * @stable ICU 4.2
1755    */
1756   int32_t toUTF32(UChar32 *utf32, int32_t capacity, UErrorCode &errorCode) const;
1757 
1758   /* Length operations */
1759 
1760   /**
1761    * Return the length of the UnicodeString object.
1762    * The length is the number of UChar code units are in the UnicodeString.
1763    * If you want the number of code points, please use countChar32().
1764    * @return the length of the UnicodeString object
1765    * @see countChar32
1766    * @stable ICU 2.0
1767    */
1768   inline int32_t length(void) const;
1769 
1770   /**
1771    * Count Unicode code points in the length UChar code units of the string.
1772    * A code point may occupy either one or two UChar code units.
1773    * Counting code points involves reading all code units.
1774    *
1775    * This functions is basically the inverse of moveIndex32().
1776    *
1777    * @param start the index of the first code unit to check
1778    * @param length the number of UChar code units to check
1779    * @return the number of code points in the specified code units
1780    * @see length
1781    * @stable ICU 2.0
1782    */
1783   int32_t
1784   countChar32(int32_t start=0, int32_t length=INT32_MAX) const;
1785 
1786   /**
1787    * Check if the length UChar code units of the string
1788    * contain more Unicode code points than a certain number.
1789    * This is more efficient than counting all code points in this part of the string
1790    * and comparing that number with a threshold.
1791    * This function may not need to scan the string at all if the length
1792    * falls within a certain range, and
1793    * never needs to count more than 'number+1' code points.
1794    * Logically equivalent to (countChar32(start, length)>number).
1795    * A Unicode code point may occupy either one or two UChar code units.
1796    *
1797    * @param start the index of the first code unit to check (0 for the entire string)
1798    * @param length the number of UChar code units to check
1799    *               (use INT32_MAX for the entire string; remember that start/length
1800    *                values are pinned)
1801    * @param number The number of code points in the (sub)string is compared against
1802    *               the 'number' parameter.
1803    * @return Boolean value for whether the string contains more Unicode code points
1804    *         than 'number'. Same as (u_countChar32(s, length)>number).
1805    * @see countChar32
1806    * @see u_strHasMoreChar32Than
1807    * @stable ICU 2.4
1808    */
1809   UBool
1810   hasMoreChar32Than(int32_t start, int32_t length, int32_t number) const;
1811 
1812   /**
1813    * Determine if this string is empty.
1814    * @return TRUE if this string contains 0 characters, FALSE otherwise.
1815    * @stable ICU 2.0
1816    */
1817   inline UBool isEmpty(void) const;
1818 
1819   /**
1820    * Return the capacity of the internal buffer of the UnicodeString object.
1821    * This is useful together with the getBuffer functions.
1822    * See there for details.
1823    *
1824    * @return the number of UChars available in the internal buffer
1825    * @see getBuffer
1826    * @stable ICU 2.0
1827    */
1828   inline int32_t getCapacity(void) const;
1829 
1830   /* Other operations */
1831 
1832   /**
1833    * Generate a hash code for this object.
1834    * @return The hash code of this UnicodeString.
1835    * @stable ICU 2.0
1836    */
1837   inline int32_t hashCode(void) const;
1838 
1839   /**
1840    * Determine if this object contains a valid string.
1841    * A bogus string has no value. It is different from an empty string,
1842    * although in both cases isEmpty() returns TRUE and length() returns 0.
1843    * setToBogus() and isBogus() can be used to indicate that no string value is available.
1844    * For a bogus string, getBuffer() and getTerminatedBuffer() return NULL, and
1845    * length() returns 0.
1846    *
1847    * @return TRUE if the string is bogus/invalid, FALSE otherwise
1848    * @see setToBogus()
1849    * @stable ICU 2.0
1850    */
1851   inline UBool isBogus(void) const;
1852 
1853 
1854   //========================================
1855   // Write operations
1856   //========================================
1857 
1858   /* Assignment operations */
1859 
1860   /**
1861    * Assignment operator.  Replace the characters in this UnicodeString
1862    * with the characters from <TT>srcText</TT>.
1863    *
1864    * Starting with ICU 2.4, the assignment operator and the copy constructor
1865    * allocate a new buffer and copy the buffer contents even for readonly aliases.
1866    * By contrast, the fastCopyFrom() function implements the old,
1867    * more efficient but less safe behavior
1868    * of making this string also a readonly alias to the same buffer.
1869    *
1870    * If the source object has an "open" buffer from getBuffer(minCapacity),
1871    * then the copy is an empty string.
1872    *
1873    * @param srcText The text containing the characters to replace
1874    * @return a reference to this
1875    * @stable ICU 2.0
1876    * @see fastCopyFrom
1877    */
1878   UnicodeString &operator=(const UnicodeString &srcText);
1879 
1880   /**
1881    * Almost the same as the assignment operator.
1882    * Replace the characters in this UnicodeString
1883    * with the characters from <code>srcText</code>.
1884    *
1885    * This function works the same as the assignment operator
1886    * for all strings except for ones that are readonly aliases.
1887    *
1888    * Starting with ICU 2.4, the assignment operator and the copy constructor
1889    * allocate a new buffer and copy the buffer contents even for readonly aliases.
1890    * This function implements the old, more efficient but less safe behavior
1891    * of making this string also a readonly alias to the same buffer.
1892    *
1893    * The fastCopyFrom function must be used only if it is known that the lifetime of
1894    * this UnicodeString does not exceed the lifetime of the aliased buffer
1895    * including its contents, for example for strings from resource bundles
1896    * or aliases to string constants.
1897    *
1898    * If the source object has an "open" buffer from getBuffer(minCapacity),
1899    * then the copy is an empty string.
1900    *
1901    * @param src The text containing the characters to replace.
1902    * @return a reference to this
1903    * @stable ICU 2.4
1904    */
1905   UnicodeString &fastCopyFrom(const UnicodeString &src);
1906 
1907 #if U_HAVE_RVALUE_REFERENCES
1908   /**
1909    * Move assignment operator, might leave src in bogus state.
1910    * This string will have the same contents and state that the source string had.
1911    * The behavior is undefined if *this and src are the same object.
1912    * @param src source string
1913    * @return *this
1914    * @stable ICU 56
1915    */
1916   UnicodeString &operator=(UnicodeString &&src) U_NOEXCEPT {
1917     return moveFrom(src);
1918   }
1919 #endif
1920   // do not use #ifndef U_HIDE_DRAFT_API for moveFrom, needed by non-draft API
1921   /**
1922    * Move assignment, might leave src in bogus state.
1923    * This string will have the same contents and state that the source string had.
1924    * The behavior is undefined if *this and src are the same object.
1925    *
1926    * Can be called explicitly, does not need C++11 support.
1927    * @param src source string
1928    * @return *this
1929    * @draft ICU 56
1930    */
1931   UnicodeString &moveFrom(UnicodeString &src) U_NOEXCEPT;
1932 
1933   /**
1934    * Swap strings.
1935    * @param other other string
1936    * @stable ICU 56
1937    */
1938   void swap(UnicodeString &other) U_NOEXCEPT;
1939 
1940   /**
1941    * Non-member UnicodeString swap function.
1942    * @param s1 will get s2's contents and state
1943    * @param s2 will get s1's contents and state
1944    * @stable ICU 56
1945    */
1946   friend U_COMMON_API inline void U_EXPORT2
swap(UnicodeString & s1,UnicodeString & s2)1947   swap(UnicodeString &s1, UnicodeString &s2) U_NOEXCEPT {
1948     s1.swap(s2);
1949   }
1950 
1951   /**
1952    * Assignment operator.  Replace the characters in this UnicodeString
1953    * with the code unit <TT>ch</TT>.
1954    * @param ch the code unit to replace
1955    * @return a reference to this
1956    * @stable ICU 2.0
1957    */
1958   inline UnicodeString& operator= (UChar ch);
1959 
1960   /**
1961    * Assignment operator.  Replace the characters in this UnicodeString
1962    * with the code point <TT>ch</TT>.
1963    * @param ch the code point to replace
1964    * @return a reference to this
1965    * @stable ICU 2.0
1966    */
1967   inline UnicodeString& operator= (UChar32 ch);
1968 
1969   /**
1970    * Set the text in the UnicodeString object to the characters
1971    * in <TT>srcText</TT> in the range
1972    * [<TT>srcStart</TT>, <TT>srcText.length()</TT>).
1973    * <TT>srcText</TT> is not modified.
1974    * @param srcText the source for the new characters
1975    * @param srcStart the offset into <TT>srcText</TT> where new characters
1976    * will be obtained
1977    * @return a reference to this
1978    * @stable ICU 2.2
1979    */
1980   inline UnicodeString& setTo(const UnicodeString& srcText,
1981                int32_t srcStart);
1982 
1983   /**
1984    * Set the text in the UnicodeString object to the characters
1985    * in <TT>srcText</TT> in the range
1986    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
1987    * <TT>srcText</TT> is not modified.
1988    * @param srcText the source for the new characters
1989    * @param srcStart the offset into <TT>srcText</TT> where new characters
1990    * will be obtained
1991    * @param srcLength the number of characters in <TT>srcText</TT> in the
1992    * replace string.
1993    * @return a reference to this
1994    * @stable ICU 2.0
1995    */
1996   inline UnicodeString& setTo(const UnicodeString& srcText,
1997                int32_t srcStart,
1998                int32_t srcLength);
1999 
2000   /**
2001    * Set the text in the UnicodeString object to the characters in
2002    * <TT>srcText</TT>.
2003    * <TT>srcText</TT> is not modified.
2004    * @param srcText the source for the new characters
2005    * @return a reference to this
2006    * @stable ICU 2.0
2007    */
2008   inline UnicodeString& setTo(const UnicodeString& srcText);
2009 
2010   /**
2011    * Set the characters in the UnicodeString object to the characters
2012    * in <TT>srcChars</TT>. <TT>srcChars</TT> is not modified.
2013    * @param srcChars the source for the new characters
2014    * @param srcLength the number of Unicode characters in srcChars.
2015    * @return a reference to this
2016    * @stable ICU 2.0
2017    */
2018   inline UnicodeString& setTo(const UChar *srcChars,
2019                int32_t srcLength);
2020 
2021   /**
2022    * Set the characters in the UnicodeString object to the code unit
2023    * <TT>srcChar</TT>.
2024    * @param srcChar the code unit which becomes the UnicodeString's character
2025    * content
2026    * @return a reference to this
2027    * @stable ICU 2.0
2028    */
2029   UnicodeString& setTo(UChar srcChar);
2030 
2031   /**
2032    * Set the characters in the UnicodeString object to the code point
2033    * <TT>srcChar</TT>.
2034    * @param srcChar the code point which becomes the UnicodeString's character
2035    * content
2036    * @return a reference to this
2037    * @stable ICU 2.0
2038    */
2039   UnicodeString& setTo(UChar32 srcChar);
2040 
2041   /**
2042    * Aliasing setTo() function, analogous to the readonly-aliasing UChar* constructor.
2043    * The text will be used for the UnicodeString object, but
2044    * it will not be released when the UnicodeString is destroyed.
2045    * This has copy-on-write semantics:
2046    * When the string is modified, then the buffer is first copied into
2047    * newly allocated memory.
2048    * The aliased buffer is never modified.
2049    *
2050    * In an assignment to another UnicodeString, when using the copy constructor
2051    * or the assignment operator, the text will be copied.
2052    * When using fastCopyFrom(), the text will be aliased again,
2053    * so that both strings then alias the same readonly-text.
2054    *
2055    * @param isTerminated specifies if <code>text</code> is <code>NUL</code>-terminated.
2056    *                     This must be true if <code>textLength==-1</code>.
2057    * @param text The characters to alias for the UnicodeString.
2058    * @param textLength The number of Unicode characters in <code>text</code> to alias.
2059    *                   If -1, then this constructor will determine the length
2060    *                   by calling <code>u_strlen()</code>.
2061    * @return a reference to this
2062    * @stable ICU 2.0
2063    */
2064   UnicodeString &setTo(UBool isTerminated,
2065                        const UChar *text,
2066                        int32_t textLength);
2067 
2068   /**
2069    * Aliasing setTo() function, analogous to the writable-aliasing UChar* constructor.
2070    * The text will be used for the UnicodeString object, but
2071    * it will not be released when the UnicodeString is destroyed.
2072    * This has write-through semantics:
2073    * For as long as the capacity of the buffer is sufficient, write operations
2074    * will directly affect the buffer. When more capacity is necessary, then
2075    * a new buffer will be allocated and the contents copied as with regularly
2076    * constructed strings.
2077    * In an assignment to another UnicodeString, the buffer will be copied.
2078    * The extract(UChar *dst) function detects whether the dst pointer is the same
2079    * as the string buffer itself and will in this case not copy the contents.
2080    *
2081    * @param buffer The characters to alias for the UnicodeString.
2082    * @param buffLength The number of Unicode characters in <code>buffer</code> to alias.
2083    * @param buffCapacity The size of <code>buffer</code> in UChars.
2084    * @return a reference to this
2085    * @stable ICU 2.0
2086    */
2087   UnicodeString &setTo(UChar *buffer,
2088                        int32_t buffLength,
2089                        int32_t buffCapacity);
2090 
2091   /**
2092    * Make this UnicodeString object invalid.
2093    * The string will test TRUE with isBogus().
2094    *
2095    * A bogus string has no value. It is different from an empty string.
2096    * It can be used to indicate that no string value is available.
2097    * getBuffer() and getTerminatedBuffer() return NULL, and
2098    * length() returns 0.
2099    *
2100    * This utility function is used throughout the UnicodeString
2101    * implementation to indicate that a UnicodeString operation failed,
2102    * and may be used in other functions,
2103    * especially but not exclusively when such functions do not
2104    * take a UErrorCode for simplicity.
2105    *
2106    * The following methods, and no others, will clear a string object's bogus flag:
2107    * - remove()
2108    * - remove(0, INT32_MAX)
2109    * - truncate(0)
2110    * - operator=() (assignment operator)
2111    * - setTo(...)
2112    *
2113    * The simplest ways to turn a bogus string into an empty one
2114    * is to use the remove() function.
2115    * Examples for other functions that are equivalent to "set to empty string":
2116    * \code
2117    * if(s.isBogus()) {
2118    *   s.remove();           // set to an empty string (remove all), or
2119    *   s.remove(0, INT32_MAX); // set to an empty string (remove all), or
2120    *   s.truncate(0);        // set to an empty string (complete truncation), or
2121    *   s=UnicodeString();    // assign an empty string, or
2122    *   s.setTo((UChar32)-1); // set to a pseudo code point that is out of range, or
2123    *   static const UChar nul=0;
2124    *   s.setTo(&nul, 0);     // set to an empty C Unicode string
2125    * }
2126    * \endcode
2127    *
2128    * @see isBogus()
2129    * @stable ICU 2.0
2130    */
2131   void setToBogus();
2132 
2133   /**
2134    * Set the character at the specified offset to the specified character.
2135    * @param offset A valid offset into the text of the character to set
2136    * @param ch The new character
2137    * @return A reference to this
2138    * @stable ICU 2.0
2139    */
2140   UnicodeString& setCharAt(int32_t offset,
2141                UChar ch);
2142 
2143 
2144   /* Append operations */
2145 
2146   /**
2147    * Append operator. Append the code unit <TT>ch</TT> to the UnicodeString
2148    * object.
2149    * @param ch the code unit to be appended
2150    * @return a reference to this
2151    * @stable ICU 2.0
2152    */
2153  inline  UnicodeString& operator+= (UChar ch);
2154 
2155   /**
2156    * Append operator. Append the code point <TT>ch</TT> to the UnicodeString
2157    * object.
2158    * @param ch the code point to be appended
2159    * @return a reference to this
2160    * @stable ICU 2.0
2161    */
2162  inline  UnicodeString& operator+= (UChar32 ch);
2163 
2164   /**
2165    * Append operator. Append the characters in <TT>srcText</TT> to the
2166    * UnicodeString object. <TT>srcText</TT> is not modified.
2167    * @param srcText the source for the new characters
2168    * @return a reference to this
2169    * @stable ICU 2.0
2170    */
2171   inline UnicodeString& operator+= (const UnicodeString& srcText);
2172 
2173   /**
2174    * Append the characters
2175    * in <TT>srcText</TT> in the range
2176    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) to the
2177    * UnicodeString object at offset <TT>start</TT>. <TT>srcText</TT>
2178    * is not modified.
2179    * @param srcText the source for the new characters
2180    * @param srcStart the offset into <TT>srcText</TT> where new characters
2181    * will be obtained
2182    * @param srcLength the number of characters in <TT>srcText</TT> in
2183    * the append string
2184    * @return a reference to this
2185    * @stable ICU 2.0
2186    */
2187   inline UnicodeString& append(const UnicodeString& srcText,
2188             int32_t srcStart,
2189             int32_t srcLength);
2190 
2191   /**
2192    * Append the characters in <TT>srcText</TT> to the UnicodeString object.
2193    * <TT>srcText</TT> is not modified.
2194    * @param srcText the source for the new characters
2195    * @return a reference to this
2196    * @stable ICU 2.0
2197    */
2198   inline UnicodeString& append(const UnicodeString& srcText);
2199 
2200   /**
2201    * Append the characters in <TT>srcChars</TT> in the range
2202    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) to the UnicodeString
2203    * object at offset
2204    * <TT>start</TT>. <TT>srcChars</TT> is not modified.
2205    * @param srcChars the source for the new characters
2206    * @param srcStart the offset into <TT>srcChars</TT> where new characters
2207    * will be obtained
2208    * @param srcLength the number of characters in <TT>srcChars</TT> in
2209    *                  the append string; can be -1 if <TT>srcChars</TT> is NUL-terminated
2210    * @return a reference to this
2211    * @stable ICU 2.0
2212    */
2213   inline UnicodeString& append(const UChar *srcChars,
2214             int32_t srcStart,
2215             int32_t srcLength);
2216 
2217   /**
2218    * Append the characters in <TT>srcChars</TT> to the UnicodeString object
2219    * at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.
2220    * @param srcChars the source for the new characters
2221    * @param srcLength the number of Unicode characters in <TT>srcChars</TT>;
2222    *                  can be -1 if <TT>srcChars</TT> is NUL-terminated
2223    * @return a reference to this
2224    * @stable ICU 2.0
2225    */
2226   inline UnicodeString& append(const UChar *srcChars,
2227             int32_t srcLength);
2228 
2229   /**
2230    * Append the code unit <TT>srcChar</TT> to the UnicodeString object.
2231    * @param srcChar the code unit to append
2232    * @return a reference to this
2233    * @stable ICU 2.0
2234    */
2235   inline UnicodeString& append(UChar srcChar);
2236 
2237   /**
2238    * Append the code point <TT>srcChar</TT> to the UnicodeString object.
2239    * @param srcChar the code point to append
2240    * @return a reference to this
2241    * @stable ICU 2.0
2242    */
2243   UnicodeString& append(UChar32 srcChar);
2244 
2245 
2246   /* Insert operations */
2247 
2248   /**
2249    * Insert the characters in <TT>srcText</TT> in the range
2250    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) into the UnicodeString
2251    * object at offset <TT>start</TT>. <TT>srcText</TT> is not modified.
2252    * @param start the offset where the insertion begins
2253    * @param srcText the source for the new characters
2254    * @param srcStart the offset into <TT>srcText</TT> where new characters
2255    * will be obtained
2256    * @param srcLength the number of characters in <TT>srcText</TT> in
2257    * the insert string
2258    * @return a reference to this
2259    * @stable ICU 2.0
2260    */
2261   inline UnicodeString& insert(int32_t start,
2262             const UnicodeString& srcText,
2263             int32_t srcStart,
2264             int32_t srcLength);
2265 
2266   /**
2267    * Insert the characters in <TT>srcText</TT> into the UnicodeString object
2268    * at offset <TT>start</TT>. <TT>srcText</TT> is not modified.
2269    * @param start the offset where the insertion begins
2270    * @param srcText the source for the new characters
2271    * @return a reference to this
2272    * @stable ICU 2.0
2273    */
2274   inline UnicodeString& insert(int32_t start,
2275             const UnicodeString& srcText);
2276 
2277   /**
2278    * Insert the characters in <TT>srcChars</TT> in the range
2279    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>) into the UnicodeString
2280    *  object at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.
2281    * @param start the offset at which the insertion begins
2282    * @param srcChars the source for the new characters
2283    * @param srcStart the offset into <TT>srcChars</TT> where new characters
2284    * will be obtained
2285    * @param srcLength the number of characters in <TT>srcChars</TT>
2286    * in the insert string
2287    * @return a reference to this
2288    * @stable ICU 2.0
2289    */
2290   inline UnicodeString& insert(int32_t start,
2291             const UChar *srcChars,
2292             int32_t srcStart,
2293             int32_t srcLength);
2294 
2295   /**
2296    * Insert the characters in <TT>srcChars</TT> into the UnicodeString object
2297    * at offset <TT>start</TT>. <TT>srcChars</TT> is not modified.
2298    * @param start the offset where the insertion begins
2299    * @param srcChars the source for the new characters
2300    * @param srcLength the number of Unicode characters in srcChars.
2301    * @return a reference to this
2302    * @stable ICU 2.0
2303    */
2304   inline UnicodeString& insert(int32_t start,
2305             const UChar *srcChars,
2306             int32_t srcLength);
2307 
2308   /**
2309    * Insert the code unit <TT>srcChar</TT> into the UnicodeString object at
2310    * offset <TT>start</TT>.
2311    * @param start the offset at which the insertion occurs
2312    * @param srcChar the code unit to insert
2313    * @return a reference to this
2314    * @stable ICU 2.0
2315    */
2316   inline UnicodeString& insert(int32_t start,
2317             UChar srcChar);
2318 
2319   /**
2320    * Insert the code point <TT>srcChar</TT> into the UnicodeString object at
2321    * offset <TT>start</TT>.
2322    * @param start the offset at which the insertion occurs
2323    * @param srcChar the code point to insert
2324    * @return a reference to this
2325    * @stable ICU 2.0
2326    */
2327   inline UnicodeString& insert(int32_t start,
2328             UChar32 srcChar);
2329 
2330 
2331   /* Replace operations */
2332 
2333   /**
2334    * Replace the characters in the range
2335    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in
2336    * <TT>srcText</TT> in the range
2337    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>).
2338    * <TT>srcText</TT> is not modified.
2339    * @param start the offset at which the replace operation begins
2340    * @param length the number of characters to replace. The character at
2341    * <TT>start + length</TT> is not modified.
2342    * @param srcText the source for the new characters
2343    * @param srcStart the offset into <TT>srcText</TT> where new characters
2344    * will be obtained
2345    * @param srcLength the number of characters in <TT>srcText</TT> in
2346    * the replace string
2347    * @return a reference to this
2348    * @stable ICU 2.0
2349    */
2350   UnicodeString& replace(int32_t start,
2351              int32_t length,
2352              const UnicodeString& srcText,
2353              int32_t srcStart,
2354              int32_t srcLength);
2355 
2356   /**
2357    * Replace the characters in the range
2358    * [<TT>start</TT>, <TT>start + length</TT>)
2359    * with the characters in <TT>srcText</TT>.  <TT>srcText</TT> is
2360    *  not modified.
2361    * @param start the offset at which the replace operation begins
2362    * @param length the number of characters to replace. The character at
2363    * <TT>start + length</TT> is not modified.
2364    * @param srcText the source for the new characters
2365    * @return a reference to this
2366    * @stable ICU 2.0
2367    */
2368   UnicodeString& replace(int32_t start,
2369              int32_t length,
2370              const UnicodeString& srcText);
2371 
2372   /**
2373    * Replace the characters in the range
2374    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in
2375    * <TT>srcChars</TT> in the range
2376    * [<TT>srcStart</TT>, <TT>srcStart + srcLength</TT>). <TT>srcChars</TT>
2377    * is not modified.
2378    * @param start the offset at which the replace operation begins
2379    * @param length the number of characters to replace.  The character at
2380    * <TT>start + length</TT> is not modified.
2381    * @param srcChars the source for the new characters
2382    * @param srcStart the offset into <TT>srcChars</TT> where new characters
2383    * will be obtained
2384    * @param srcLength the number of characters in <TT>srcChars</TT>
2385    * in the replace string
2386    * @return a reference to this
2387    * @stable ICU 2.0
2388    */
2389   UnicodeString& replace(int32_t start,
2390              int32_t length,
2391              const UChar *srcChars,
2392              int32_t srcStart,
2393              int32_t srcLength);
2394 
2395   /**
2396    * Replace the characters in the range
2397    * [<TT>start</TT>, <TT>start + length</TT>) with the characters in
2398    * <TT>srcChars</TT>.  <TT>srcChars</TT> is not modified.
2399    * @param start the offset at which the replace operation begins
2400    * @param length number of characters to replace.  The character at
2401    * <TT>start + length</TT> is not modified.
2402    * @param srcChars the source for the new characters
2403    * @param srcLength the number of Unicode characters in srcChars
2404    * @return a reference to this
2405    * @stable ICU 2.0
2406    */
2407   inline UnicodeString& replace(int32_t start,
2408              int32_t length,
2409              const UChar *srcChars,
2410              int32_t srcLength);
2411 
2412   /**
2413    * Replace the characters in the range
2414    * [<TT>start</TT>, <TT>start + length</TT>) with the code unit
2415    * <TT>srcChar</TT>.
2416    * @param start the offset at which the replace operation begins
2417    * @param length the number of characters to replace.  The character at
2418    * <TT>start + length</TT> is not modified.
2419    * @param srcChar the new code unit
2420    * @return a reference to this
2421    * @stable ICU 2.0
2422    */
2423   inline UnicodeString& replace(int32_t start,
2424              int32_t length,
2425              UChar srcChar);
2426 
2427   /**
2428    * Replace the characters in the range
2429    * [<TT>start</TT>, <TT>start + length</TT>) with the code point
2430    * <TT>srcChar</TT>.
2431    * @param start the offset at which the replace operation begins
2432    * @param length the number of characters to replace.  The character at
2433    * <TT>start + length</TT> is not modified.
2434    * @param srcChar the new code point
2435    * @return a reference to this
2436    * @stable ICU 2.0
2437    */
2438   UnicodeString& replace(int32_t start, int32_t length, UChar32 srcChar);
2439 
2440   /**
2441    * Replace the characters in the range [<TT>start</TT>, <TT>limit</TT>)
2442    * with the characters in <TT>srcText</TT>. <TT>srcText</TT> is not modified.
2443    * @param start the offset at which the replace operation begins
2444    * @param limit the offset immediately following the replace range
2445    * @param srcText the source for the new characters
2446    * @return a reference to this
2447    * @stable ICU 2.0
2448    */
2449   inline UnicodeString& replaceBetween(int32_t start,
2450                 int32_t limit,
2451                 const UnicodeString& srcText);
2452 
2453   /**
2454    * Replace the characters in the range [<TT>start</TT>, <TT>limit</TT>)
2455    * with the characters in <TT>srcText</TT> in the range
2456    * [<TT>srcStart</TT>, <TT>srcLimit</TT>). <TT>srcText</TT> is not modified.
2457    * @param start the offset at which the replace operation begins
2458    * @param limit the offset immediately following the replace range
2459    * @param srcText the source for the new characters
2460    * @param srcStart the offset into <TT>srcChars</TT> where new characters
2461    * will be obtained
2462    * @param srcLimit the offset immediately following the range to copy
2463    * in <TT>srcText</TT>
2464    * @return a reference to this
2465    * @stable ICU 2.0
2466    */
2467   inline UnicodeString& replaceBetween(int32_t start,
2468                 int32_t limit,
2469                 const UnicodeString& srcText,
2470                 int32_t srcStart,
2471                 int32_t srcLimit);
2472 
2473   /**
2474    * Replace a substring of this object with the given text.
2475    * @param start the beginning index, inclusive; <code>0 <= start
2476    * <= limit</code>.
2477    * @param limit the ending index, exclusive; <code>start <= limit
2478    * <= length()</code>.
2479    * @param text the text to replace characters <code>start</code>
2480    * to <code>limit - 1</code>
2481    * @stable ICU 2.0
2482    */
2483   virtual void handleReplaceBetween(int32_t start,
2484                                     int32_t limit,
2485                                     const UnicodeString& text);
2486 
2487   /**
2488    * Replaceable API
2489    * @return TRUE if it has MetaData
2490    * @stable ICU 2.4
2491    */
2492   virtual UBool hasMetaData() const;
2493 
2494   /**
2495    * Copy a substring of this object, retaining attribute (out-of-band)
2496    * information.  This method is used to duplicate or reorder substrings.
2497    * The destination index must not overlap the source range.
2498    *
2499    * @param start the beginning index, inclusive; <code>0 <= start <=
2500    * limit</code>.
2501    * @param limit the ending index, exclusive; <code>start <= limit <=
2502    * length()</code>.
2503    * @param dest the destination index.  The characters from
2504    * <code>start..limit-1</code> will be copied to <code>dest</code>.
2505    * Implementations of this method may assume that <code>dest <= start ||
2506    * dest >= limit</code>.
2507    * @stable ICU 2.0
2508    */
2509   virtual void copy(int32_t start, int32_t limit, int32_t dest);
2510 
2511   /* Search and replace operations */
2512 
2513   /**
2514    * Replace all occurrences of characters in oldText with the characters
2515    * in newText
2516    * @param oldText the text containing the search text
2517    * @param newText the text containing the replacement text
2518    * @return a reference to this
2519    * @stable ICU 2.0
2520    */
2521   inline UnicodeString& findAndReplace(const UnicodeString& oldText,
2522                 const UnicodeString& newText);
2523 
2524   /**
2525    * Replace all occurrences of characters in oldText with characters
2526    * in newText
2527    * in the range [<TT>start</TT>, <TT>start + length</TT>).
2528    * @param start the start of the range in which replace will performed
2529    * @param length the length of the range in which replace will be performed
2530    * @param oldText the text containing the search text
2531    * @param newText the text containing the replacement text
2532    * @return a reference to this
2533    * @stable ICU 2.0
2534    */
2535   inline UnicodeString& findAndReplace(int32_t start,
2536                 int32_t length,
2537                 const UnicodeString& oldText,
2538                 const UnicodeString& newText);
2539 
2540   /**
2541    * Replace all occurrences of characters in oldText in the range
2542    * [<TT>oldStart</TT>, <TT>oldStart + oldLength</TT>) with the characters
2543    * in newText in the range
2544    * [<TT>newStart</TT>, <TT>newStart + newLength</TT>)
2545    * in the range [<TT>start</TT>, <TT>start + length</TT>).
2546    * @param start the start of the range in which replace will performed
2547    * @param length the length of the range in which replace will be performed
2548    * @param oldText the text containing the search text
2549    * @param oldStart the start of the search range in <TT>oldText</TT>
2550    * @param oldLength the length of the search range in <TT>oldText</TT>
2551    * @param newText the text containing the replacement text
2552    * @param newStart the start of the replacement range in <TT>newText</TT>
2553    * @param newLength the length of the replacement range in <TT>newText</TT>
2554    * @return a reference to this
2555    * @stable ICU 2.0
2556    */
2557   UnicodeString& findAndReplace(int32_t start,
2558                 int32_t length,
2559                 const UnicodeString& oldText,
2560                 int32_t oldStart,
2561                 int32_t oldLength,
2562                 const UnicodeString& newText,
2563                 int32_t newStart,
2564                 int32_t newLength);
2565 
2566 
2567   /* Remove operations */
2568 
2569   /**
2570    * Remove all characters from the UnicodeString object.
2571    * @return a reference to this
2572    * @stable ICU 2.0
2573    */
2574   inline UnicodeString& remove(void);
2575 
2576   /**
2577    * Remove the characters in the range
2578    * [<TT>start</TT>, <TT>start + length</TT>) from the UnicodeString object.
2579    * @param start the offset of the first character to remove
2580    * @param length the number of characters to remove
2581    * @return a reference to this
2582    * @stable ICU 2.0
2583    */
2584   inline UnicodeString& remove(int32_t start,
2585                                int32_t length = (int32_t)INT32_MAX);
2586 
2587   /**
2588    * Remove the characters in the range
2589    * [<TT>start</TT>, <TT>limit</TT>) from the UnicodeString object.
2590    * @param start the offset of the first character to remove
2591    * @param limit the offset immediately following the range to remove
2592    * @return a reference to this
2593    * @stable ICU 2.0
2594    */
2595   inline UnicodeString& removeBetween(int32_t start,
2596                                       int32_t limit = (int32_t)INT32_MAX);
2597 
2598   /**
2599    * Retain only the characters in the range
2600    * [<code>start</code>, <code>limit</code>) from the UnicodeString object.
2601    * Removes characters before <code>start</code> and at and after <code>limit</code>.
2602    * @param start the offset of the first character to retain
2603    * @param limit the offset immediately following the range to retain
2604    * @return a reference to this
2605    * @stable ICU 4.4
2606    */
2607   inline UnicodeString &retainBetween(int32_t start, int32_t limit = INT32_MAX);
2608 
2609   /* Length operations */
2610 
2611   /**
2612    * Pad the start of this UnicodeString with the character <TT>padChar</TT>.
2613    * If the length of this UnicodeString is less than targetLength,
2614    * length() - targetLength copies of padChar will be added to the
2615    * beginning of this UnicodeString.
2616    * @param targetLength the desired length of the string
2617    * @param padChar the character to use for padding. Defaults to
2618    * space (U+0020)
2619    * @return TRUE if the text was padded, FALSE otherwise.
2620    * @stable ICU 2.0
2621    */
2622   UBool padLeading(int32_t targetLength,
2623                     UChar padChar = 0x0020);
2624 
2625   /**
2626    * Pad the end of this UnicodeString with the character <TT>padChar</TT>.
2627    * If the length of this UnicodeString is less than targetLength,
2628    * length() - targetLength copies of padChar will be added to the
2629    * end of this UnicodeString.
2630    * @param targetLength the desired length of the string
2631    * @param padChar the character to use for padding. Defaults to
2632    * space (U+0020)
2633    * @return TRUE if the text was padded, FALSE otherwise.
2634    * @stable ICU 2.0
2635    */
2636   UBool padTrailing(int32_t targetLength,
2637                      UChar padChar = 0x0020);
2638 
2639   /**
2640    * Truncate this UnicodeString to the <TT>targetLength</TT>.
2641    * @param targetLength the desired length of this UnicodeString.
2642    * @return TRUE if the text was truncated, FALSE otherwise
2643    * @stable ICU 2.0
2644    */
2645   inline UBool truncate(int32_t targetLength);
2646 
2647   /**
2648    * Trims leading and trailing whitespace from this UnicodeString.
2649    * @return a reference to this
2650    * @stable ICU 2.0
2651    */
2652   UnicodeString& trim(void);
2653 
2654 
2655   /* Miscellaneous operations */
2656 
2657   /**
2658    * Reverse this UnicodeString in place.
2659    * @return a reference to this
2660    * @stable ICU 2.0
2661    */
2662   inline UnicodeString& reverse(void);
2663 
2664   /**
2665    * Reverse the range [<TT>start</TT>, <TT>start + length</TT>) in
2666    * this UnicodeString.
2667    * @param start the start of the range to reverse
2668    * @param length the number of characters to to reverse
2669    * @return a reference to this
2670    * @stable ICU 2.0
2671    */
2672   inline UnicodeString& reverse(int32_t start,
2673              int32_t length);
2674 
2675   /**
2676    * Convert the characters in this to UPPER CASE following the conventions of
2677    * the default locale.
2678    * @return A reference to this.
2679    * @stable ICU 2.0
2680    */
2681   UnicodeString& toUpper(void);
2682 
2683   /**
2684    * Convert the characters in this to UPPER CASE following the conventions of
2685    * a specific locale.
2686    * @param locale The locale containing the conventions to use.
2687    * @return A reference to this.
2688    * @stable ICU 2.0
2689    */
2690   UnicodeString& toUpper(const Locale& locale);
2691 
2692   /**
2693    * Convert the characters in this to lower case following the conventions of
2694    * the default locale.
2695    * @return A reference to this.
2696    * @stable ICU 2.0
2697    */
2698   UnicodeString& toLower(void);
2699 
2700   /**
2701    * Convert the characters in this to lower case following the conventions of
2702    * a specific locale.
2703    * @param locale The locale containing the conventions to use.
2704    * @return A reference to this.
2705    * @stable ICU 2.0
2706    */
2707   UnicodeString& toLower(const Locale& locale);
2708 
2709 #if !UCONFIG_NO_BREAK_ITERATION
2710 
2711   /**
2712    * Titlecase this string, convenience function using the default locale.
2713    *
2714    * Casing is locale-dependent and context-sensitive.
2715    * Titlecasing uses a break iterator to find the first characters of words
2716    * that are to be titlecased. It titlecases those characters and lowercases
2717    * all others.
2718    *
2719    * The titlecase break iterator can be provided to customize for arbitrary
2720    * styles, using rules and dictionaries beyond the standard iterators.
2721    * It may be more efficient to always provide an iterator to avoid
2722    * opening and closing one for each string.
2723    * The standard titlecase iterator for the root locale implements the
2724    * algorithm of Unicode TR 21.
2725    *
2726    * This function uses only the setText(), first() and next() methods of the
2727    * provided break iterator.
2728    *
2729    * @param titleIter A break iterator to find the first characters of words
2730    *                  that are to be titlecased.
2731    *                  If none is provided (0), then a standard titlecase
2732    *                  break iterator is opened.
2733    *                  Otherwise the provided iterator is set to the string's text.
2734    * @return A reference to this.
2735    * @stable ICU 2.1
2736    */
2737   UnicodeString &toTitle(BreakIterator *titleIter);
2738 
2739   /**
2740    * Titlecase this string.
2741    *
2742    * Casing is locale-dependent and context-sensitive.
2743    * Titlecasing uses a break iterator to find the first characters of words
2744    * that are to be titlecased. It titlecases those characters and lowercases
2745    * all others.
2746    *
2747    * The titlecase break iterator can be provided to customize for arbitrary
2748    * styles, using rules and dictionaries beyond the standard iterators.
2749    * It may be more efficient to always provide an iterator to avoid
2750    * opening and closing one for each string.
2751    * The standard titlecase iterator for the root locale implements the
2752    * algorithm of Unicode TR 21.
2753    *
2754    * This function uses only the setText(), first() and next() methods of the
2755    * provided break iterator.
2756    *
2757    * @param titleIter A break iterator to find the first characters of words
2758    *                  that are to be titlecased.
2759    *                  If none is provided (0), then a standard titlecase
2760    *                  break iterator is opened.
2761    *                  Otherwise the provided iterator is set to the string's text.
2762    * @param locale    The locale to consider.
2763    * @return A reference to this.
2764    * @stable ICU 2.1
2765    */
2766   UnicodeString &toTitle(BreakIterator *titleIter, const Locale &locale);
2767 
2768   /**
2769    * Titlecase this string, with options.
2770    *
2771    * Casing is locale-dependent and context-sensitive.
2772    * Titlecasing uses a break iterator to find the first characters of words
2773    * that are to be titlecased. It titlecases those characters and lowercases
2774    * all others. (This can be modified with options.)
2775    *
2776    * The titlecase break iterator can be provided to customize for arbitrary
2777    * styles, using rules and dictionaries beyond the standard iterators.
2778    * It may be more efficient to always provide an iterator to avoid
2779    * opening and closing one for each string.
2780    * The standard titlecase iterator for the root locale implements the
2781    * algorithm of Unicode TR 21.
2782    *
2783    * This function uses only the setText(), first() and next() methods of the
2784    * provided break iterator.
2785    *
2786    * @param titleIter A break iterator to find the first characters of words
2787    *                  that are to be titlecased.
2788    *                  If none is provided (0), then a standard titlecase
2789    *                  break iterator is opened.
2790    *                  Otherwise the provided iterator is set to the string's text.
2791    * @param locale    The locale to consider.
2792    * @param options Options bit set, see ucasemap_open().
2793    * @return A reference to this.
2794    * @see U_TITLECASE_NO_LOWERCASE
2795    * @see U_TITLECASE_NO_BREAK_ADJUSTMENT
2796    * @see ucasemap_open
2797    * @stable ICU 3.8
2798    */
2799   UnicodeString &toTitle(BreakIterator *titleIter, const Locale &locale, uint32_t options);
2800 
2801 #endif
2802 
2803   /**
2804    * Case-folds the characters in this string.
2805    *
2806    * Case-folding is locale-independent and not context-sensitive,
2807    * but there is an option for whether to include or exclude mappings for dotted I
2808    * and dotless i that are marked with 'T' in CaseFolding.txt.
2809    *
2810    * The result may be longer or shorter than the original.
2811    *
2812    * @param options Either U_FOLD_CASE_DEFAULT or U_FOLD_CASE_EXCLUDE_SPECIAL_I
2813    * @return A reference to this.
2814    * @stable ICU 2.0
2815    */
2816   UnicodeString &foldCase(uint32_t options=0 /*U_FOLD_CASE_DEFAULT*/);
2817 
2818   //========================================
2819   // Access to the internal buffer
2820   //========================================
2821 
2822   /**
2823    * Get a read/write pointer to the internal buffer.
2824    * The buffer is guaranteed to be large enough for at least minCapacity UChars,
2825    * writable, and is still owned by the UnicodeString object.
2826    * Calls to getBuffer(minCapacity) must not be nested, and
2827    * must be matched with calls to releaseBuffer(newLength).
2828    * If the string buffer was read-only or shared,
2829    * then it will be reallocated and copied.
2830    *
2831    * An attempted nested call will return 0, and will not further modify the
2832    * state of the UnicodeString object.
2833    * It also returns 0 if the string is bogus.
2834    *
2835    * The actual capacity of the string buffer may be larger than minCapacity.
2836    * getCapacity() returns the actual capacity.
2837    * For many operations, the full capacity should be used to avoid reallocations.
2838    *
2839    * While the buffer is "open" between getBuffer(minCapacity)
2840    * and releaseBuffer(newLength), the following applies:
2841    * - The string length is set to 0.
2842    * - Any read API call on the UnicodeString object will behave like on a 0-length string.
2843    * - Any write API call on the UnicodeString object is disallowed and will have no effect.
2844    * - You can read from and write to the returned buffer.
2845    * - The previous string contents will still be in the buffer;
2846    *   if you want to use it, then you need to call length() before getBuffer(minCapacity).
2847    *   If the length() was greater than minCapacity, then any contents after minCapacity
2848    *   may be lost.
2849    *   The buffer contents is not NUL-terminated by getBuffer().
2850    *   If length()<getCapacity() then you can terminate it by writing a NUL
2851    *   at index length().
2852    * - You must call releaseBuffer(newLength) before and in order to
2853    *   return to normal UnicodeString operation.
2854    *
2855    * @param minCapacity the minimum number of UChars that are to be available
2856    *        in the buffer, starting at the returned pointer;
2857    *        default to the current string capacity if minCapacity==-1
2858    * @return a writable pointer to the internal string buffer,
2859    *         or 0 if an error occurs (nested calls, out of memory)
2860    *
2861    * @see releaseBuffer
2862    * @see getTerminatedBuffer()
2863    * @stable ICU 2.0
2864    */
2865   UChar *getBuffer(int32_t minCapacity);
2866 
2867   /**
2868    * Release a read/write buffer on a UnicodeString object with an
2869    * "open" getBuffer(minCapacity).
2870    * This function must be called in a matched pair with getBuffer(minCapacity).
2871    * releaseBuffer(newLength) must be called if and only if a getBuffer(minCapacity) is "open".
2872    *
2873    * It will set the string length to newLength, at most to the current capacity.
2874    * If newLength==-1 then it will set the length according to the
2875    * first NUL in the buffer, or to the capacity if there is no NUL.
2876    *
2877    * After calling releaseBuffer(newLength) the UnicodeString is back to normal operation.
2878    *
2879    * @param newLength the new length of the UnicodeString object;
2880    *        defaults to the current capacity if newLength is greater than that;
2881    *        if newLength==-1, it defaults to u_strlen(buffer) but not more than
2882    *        the current capacity of the string
2883    *
2884    * @see getBuffer(int32_t minCapacity)
2885    * @stable ICU 2.0
2886    */
2887   void releaseBuffer(int32_t newLength=-1);
2888 
2889   /**
2890    * Get a read-only pointer to the internal buffer.
2891    * This can be called at any time on a valid UnicodeString.
2892    *
2893    * It returns 0 if the string is bogus, or
2894    * during an "open" getBuffer(minCapacity).
2895    *
2896    * It can be called as many times as desired.
2897    * The pointer that it returns will remain valid until the UnicodeString object is modified,
2898    * at which time the pointer is semantically invalidated and must not be used any more.
2899    *
2900    * The capacity of the buffer can be determined with getCapacity().
2901    * The part after length() may or may not be initialized and valid,
2902    * depending on the history of the UnicodeString object.
2903    *
2904    * The buffer contents is (probably) not NUL-terminated.
2905    * You can check if it is with
2906    * <code>(s.length()<s.getCapacity() && buffer[s.length()]==0)</code>.
2907    * (See getTerminatedBuffer().)
2908    *
2909    * The buffer may reside in read-only memory. Its contents must not
2910    * be modified.
2911    *
2912    * @return a read-only pointer to the internal string buffer,
2913    *         or 0 if the string is empty or bogus
2914    *
2915    * @see getBuffer(int32_t minCapacity)
2916    * @see getTerminatedBuffer()
2917    * @stable ICU 2.0
2918    */
2919   inline const UChar *getBuffer() const;
2920 
2921   /**
2922    * Get a read-only pointer to the internal buffer,
2923    * making sure that it is NUL-terminated.
2924    * This can be called at any time on a valid UnicodeString.
2925    *
2926    * It returns 0 if the string is bogus, or
2927    * during an "open" getBuffer(minCapacity), or if the buffer cannot
2928    * be NUL-terminated (because memory allocation failed).
2929    *
2930    * It can be called as many times as desired.
2931    * The pointer that it returns will remain valid until the UnicodeString object is modified,
2932    * at which time the pointer is semantically invalidated and must not be used any more.
2933    *
2934    * The capacity of the buffer can be determined with getCapacity().
2935    * The part after length()+1 may or may not be initialized and valid,
2936    * depending on the history of the UnicodeString object.
2937    *
2938    * The buffer contents is guaranteed to be NUL-terminated.
2939    * getTerminatedBuffer() may reallocate the buffer if a terminating NUL
2940    * is written.
2941    * For this reason, this function is not const, unlike getBuffer().
2942    * Note that a UnicodeString may also contain NUL characters as part of its contents.
2943    *
2944    * The buffer may reside in read-only memory. Its contents must not
2945    * be modified.
2946    *
2947    * @return a read-only pointer to the internal string buffer,
2948    *         or 0 if the string is empty or bogus
2949    *
2950    * @see getBuffer(int32_t minCapacity)
2951    * @see getBuffer()
2952    * @stable ICU 2.2
2953    */
2954   const UChar *getTerminatedBuffer();
2955 
2956   //========================================
2957   // Constructors
2958   //========================================
2959 
2960   /** Construct an empty UnicodeString.
2961    * @stable ICU 2.0
2962    */
2963   inline UnicodeString();
2964 
2965   /**
2966    * Construct a UnicodeString with capacity to hold <TT>capacity</TT> UChars
2967    * @param capacity the number of UChars this UnicodeString should hold
2968    * before a resize is necessary; if count is greater than 0 and count
2969    * code points c take up more space than capacity, then capacity is adjusted
2970    * accordingly.
2971    * @param c is used to initially fill the string
2972    * @param count specifies how many code points c are to be written in the
2973    *              string
2974    * @stable ICU 2.0
2975    */
2976   UnicodeString(int32_t capacity, UChar32 c, int32_t count);
2977 
2978   /**
2979    * Single UChar (code unit) constructor.
2980    *
2981    * It is recommended to mark this constructor "explicit" by
2982    * <code>-DUNISTR_FROM_CHAR_EXPLICIT=explicit</code>
2983    * on the compiler command line or similar.
2984    * @param ch the character to place in the UnicodeString
2985    * @stable ICU 2.0
2986    */
2987   UNISTR_FROM_CHAR_EXPLICIT UnicodeString(UChar ch);
2988 
2989   /**
2990    * Single UChar32 (code point) constructor.
2991    *
2992    * It is recommended to mark this constructor "explicit" by
2993    * <code>-DUNISTR_FROM_CHAR_EXPLICIT=explicit</code>
2994    * on the compiler command line or similar.
2995    * @param ch the character to place in the UnicodeString
2996    * @stable ICU 2.0
2997    */
2998   UNISTR_FROM_CHAR_EXPLICIT UnicodeString(UChar32 ch);
2999 
3000   /**
3001    * UChar* constructor.
3002    *
3003    * It is recommended to mark this constructor "explicit" by
3004    * <code>-DUNISTR_FROM_STRING_EXPLICIT=explicit</code>
3005    * on the compiler command line or similar.
3006    * @param text The characters to place in the UnicodeString.  <TT>text</TT>
3007    * must be NULL (U+0000) terminated.
3008    * @stable ICU 2.0
3009    */
3010   UNISTR_FROM_STRING_EXPLICIT UnicodeString(const UChar *text);
3011 
3012   /**
3013    * UChar* constructor.
3014    * @param text The characters to place in the UnicodeString.
3015    * @param textLength The number of Unicode characters in <TT>text</TT>
3016    * to copy.
3017    * @stable ICU 2.0
3018    */
3019   UnicodeString(const UChar *text,
3020         int32_t textLength);
3021 
3022   /**
3023    * Readonly-aliasing UChar* constructor.
3024    * The text will be used for the UnicodeString object, but
3025    * it will not be released when the UnicodeString is destroyed.
3026    * This has copy-on-write semantics:
3027    * When the string is modified, then the buffer is first copied into
3028    * newly allocated memory.
3029    * The aliased buffer is never modified.
3030    *
3031    * In an assignment to another UnicodeString, when using the copy constructor
3032    * or the assignment operator, the text will be copied.
3033    * When using fastCopyFrom(), the text will be aliased again,
3034    * so that both strings then alias the same readonly-text.
3035    *
3036    * @param isTerminated specifies if <code>text</code> is <code>NUL</code>-terminated.
3037    *                     This must be true if <code>textLength==-1</code>.
3038    * @param text The characters to alias for the UnicodeString.
3039    * @param textLength The number of Unicode characters in <code>text</code> to alias.
3040    *                   If -1, then this constructor will determine the length
3041    *                   by calling <code>u_strlen()</code>.
3042    * @stable ICU 2.0
3043    */
3044   UnicodeString(UBool isTerminated,
3045                 const UChar *text,
3046                 int32_t textLength);
3047 
3048   /**
3049    * Writable-aliasing UChar* constructor.
3050    * The text will be used for the UnicodeString object, but
3051    * it will not be released when the UnicodeString is destroyed.
3052    * This has write-through semantics:
3053    * For as long as the capacity of the buffer is sufficient, write operations
3054    * will directly affect the buffer. When more capacity is necessary, then
3055    * a new buffer will be allocated and the contents copied as with regularly
3056    * constructed strings.
3057    * In an assignment to another UnicodeString, the buffer will be copied.
3058    * The extract(UChar *dst) function detects whether the dst pointer is the same
3059    * as the string buffer itself and will in this case not copy the contents.
3060    *
3061    * @param buffer The characters to alias for the UnicodeString.
3062    * @param buffLength The number of Unicode characters in <code>buffer</code> to alias.
3063    * @param buffCapacity The size of <code>buffer</code> in UChars.
3064    * @stable ICU 2.0
3065    */
3066   UnicodeString(UChar *buffer, int32_t buffLength, int32_t buffCapacity);
3067 
3068 #if U_CHARSET_IS_UTF8 || !UCONFIG_NO_CONVERSION
3069 
3070   /**
3071    * char* constructor.
3072    * Uses the default converter (and thus depends on the ICU conversion code)
3073    * unless U_CHARSET_IS_UTF8 is set to 1.
3074    *
3075    * For ASCII (really "invariant character") strings it is more efficient to use
3076    * the constructor that takes a US_INV (for its enum EInvariant).
3077    * For ASCII (invariant-character) string literals, see UNICODE_STRING and
3078    * UNICODE_STRING_SIMPLE.
3079    *
3080    * It is recommended to mark this constructor "explicit" by
3081    * <code>-DUNISTR_FROM_STRING_EXPLICIT=explicit</code>
3082    * on the compiler command line or similar.
3083    * @param codepageData an array of bytes, null-terminated,
3084    *                     in the platform's default codepage.
3085    * @stable ICU 2.0
3086    * @see UNICODE_STRING
3087    * @see UNICODE_STRING_SIMPLE
3088    */
3089   UNISTR_FROM_STRING_EXPLICIT UnicodeString(const char *codepageData);
3090 
3091   /**
3092    * char* constructor.
3093    * Uses the default converter (and thus depends on the ICU conversion code)
3094    * unless U_CHARSET_IS_UTF8 is set to 1.
3095    * @param codepageData an array of bytes in the platform's default codepage.
3096    * @param dataLength The number of bytes in <TT>codepageData</TT>.
3097    * @stable ICU 2.0
3098    */
3099   UnicodeString(const char *codepageData, int32_t dataLength);
3100 
3101 #endif
3102 
3103 #if !UCONFIG_NO_CONVERSION
3104 
3105   /**
3106    * char* constructor.
3107    * @param codepageData an array of bytes, null-terminated
3108    * @param codepage the encoding of <TT>codepageData</TT>.  The special
3109    * value 0 for <TT>codepage</TT> indicates that the text is in the
3110    * platform's default codepage.
3111    *
3112    * If <code>codepage</code> is an empty string (<code>""</code>),
3113    * then a simple conversion is performed on the codepage-invariant
3114    * subset ("invariant characters") of the platform encoding. See utypes.h.
3115    * Recommendation: For invariant-character strings use the constructor
3116    * UnicodeString(const char *src, int32_t length, enum EInvariant inv)
3117    * because it avoids object code dependencies of UnicodeString on
3118    * the conversion code.
3119    *
3120    * @stable ICU 2.0
3121    */
3122   UnicodeString(const char *codepageData, const char *codepage);
3123 
3124   /**
3125    * char* constructor.
3126    * @param codepageData an array of bytes.
3127    * @param dataLength The number of bytes in <TT>codepageData</TT>.
3128    * @param codepage the encoding of <TT>codepageData</TT>.  The special
3129    * value 0 for <TT>codepage</TT> indicates that the text is in the
3130    * platform's default codepage.
3131    * If <code>codepage</code> is an empty string (<code>""</code>),
3132    * then a simple conversion is performed on the codepage-invariant
3133    * subset ("invariant characters") of the platform encoding. See utypes.h.
3134    * Recommendation: For invariant-character strings use the constructor
3135    * UnicodeString(const char *src, int32_t length, enum EInvariant inv)
3136    * because it avoids object code dependencies of UnicodeString on
3137    * the conversion code.
3138    *
3139    * @stable ICU 2.0
3140    */
3141   UnicodeString(const char *codepageData, int32_t dataLength, const char *codepage);
3142 
3143   /**
3144    * char * / UConverter constructor.
3145    * This constructor uses an existing UConverter object to
3146    * convert the codepage string to Unicode and construct a UnicodeString
3147    * from that.
3148    *
3149    * The converter is reset at first.
3150    * If the error code indicates a failure before this constructor is called,
3151    * or if an error occurs during conversion or construction,
3152    * then the string will be bogus.
3153    *
3154    * This function avoids the overhead of opening and closing a converter if
3155    * multiple strings are constructed.
3156    *
3157    * @param src input codepage string
3158    * @param srcLength length of the input string, can be -1 for NUL-terminated strings
3159    * @param cnv converter object (ucnv_resetToUnicode() will be called),
3160    *        can be NULL for the default converter
3161    * @param errorCode normal ICU error code
3162    * @stable ICU 2.0
3163    */
3164   UnicodeString(
3165         const char *src, int32_t srcLength,
3166         UConverter *cnv,
3167         UErrorCode &errorCode);
3168 
3169 #endif
3170 
3171   /**
3172    * Constructs a Unicode string from an invariant-character char * string.
3173    * About invariant characters see utypes.h.
3174    * This constructor has no runtime dependency on conversion code and is
3175    * therefore recommended over ones taking a charset name string
3176    * (where the empty string "" indicates invariant-character conversion).
3177    *
3178    * Use the macro US_INV as the third, signature-distinguishing parameter.
3179    *
3180    * For example:
3181    * \code
3182    * void fn(const char *s) {
3183    *   UnicodeString ustr(s, -1, US_INV);
3184    *   // use ustr ...
3185    * }
3186    * \endcode
3187    *
3188    * @param src String using only invariant characters.
3189    * @param length Length of src, or -1 if NUL-terminated.
3190    * @param inv Signature-distinguishing paramater, use US_INV.
3191    *
3192    * @see US_INV
3193    * @stable ICU 3.2
3194    */
3195   UnicodeString(const char *src, int32_t length, enum EInvariant inv);
3196 
3197 
3198   /**
3199    * Copy constructor.
3200    *
3201    * Starting with ICU 2.4, the assignment operator and the copy constructor
3202    * allocate a new buffer and copy the buffer contents even for readonly aliases.
3203    * By contrast, the fastCopyFrom() function implements the old,
3204    * more efficient but less safe behavior
3205    * of making this string also a readonly alias to the same buffer.
3206    *
3207    * If the source object has an "open" buffer from getBuffer(minCapacity),
3208    * then the copy is an empty string.
3209    *
3210    * @param that The UnicodeString object to copy.
3211    * @stable ICU 2.0
3212    * @see fastCopyFrom
3213    */
3214   UnicodeString(const UnicodeString& that);
3215 
3216 #if U_HAVE_RVALUE_REFERENCES
3217   /**
3218    * Move constructor, might leave src in bogus state.
3219    * This string will have the same contents and state that the source string had.
3220    * @param src source string
3221    * @stable ICU 56
3222    */
3223   UnicodeString(UnicodeString &&src) U_NOEXCEPT;
3224 #endif
3225 
3226   /**
3227    * 'Substring' constructor from tail of source string.
3228    * @param src The UnicodeString object to copy.
3229    * @param srcStart The offset into <tt>src</tt> at which to start copying.
3230    * @stable ICU 2.2
3231    */
3232   UnicodeString(const UnicodeString& src, int32_t srcStart);
3233 
3234   /**
3235    * 'Substring' constructor from subrange of source string.
3236    * @param src The UnicodeString object to copy.
3237    * @param srcStart The offset into <tt>src</tt> at which to start copying.
3238    * @param srcLength The number of characters from <tt>src</tt> to copy.
3239    * @stable ICU 2.2
3240    */
3241   UnicodeString(const UnicodeString& src, int32_t srcStart, int32_t srcLength);
3242 
3243   /**
3244    * Clone this object, an instance of a subclass of Replaceable.
3245    * Clones can be used concurrently in multiple threads.
3246    * If a subclass does not implement clone(), or if an error occurs,
3247    * then NULL is returned.
3248    * The clone functions in all subclasses return a pointer to a Replaceable
3249    * because some compilers do not support covariant (same-as-this)
3250    * return types; cast to the appropriate subclass if necessary.
3251    * The caller must delete the clone.
3252    *
3253    * @return a clone of this object
3254    *
3255    * @see Replaceable::clone
3256    * @see getDynamicClassID
3257    * @stable ICU 2.6
3258    */
3259   virtual Replaceable *clone() const;
3260 
3261   /** Destructor.
3262    * @stable ICU 2.0
3263    */
3264   virtual ~UnicodeString();
3265 
3266   /**
3267    * Create a UnicodeString from a UTF-8 string.
3268    * Illegal input is replaced with U+FFFD. Otherwise, errors result in a bogus string.
3269    * Calls u_strFromUTF8WithSub().
3270    *
3271    * @param utf8 UTF-8 input string.
3272    *             Note that a StringPiece can be implicitly constructed
3273    *             from a std::string or a NUL-terminated const char * string.
3274    * @return A UnicodeString with equivalent UTF-16 contents.
3275    * @see toUTF8
3276    * @see toUTF8String
3277    * @stable ICU 4.2
3278    */
3279   static UnicodeString fromUTF8(StringPiece utf8);
3280 
3281   /**
3282    * Create a UnicodeString from a UTF-32 string.
3283    * Illegal input is replaced with U+FFFD. Otherwise, errors result in a bogus string.
3284    * Calls u_strFromUTF32WithSub().
3285    *
3286    * @param utf32 UTF-32 input string. Must not be NULL.
3287    * @param length Length of the input string, or -1 if NUL-terminated.
3288    * @return A UnicodeString with equivalent UTF-16 contents.
3289    * @see toUTF32
3290    * @stable ICU 4.2
3291    */
3292   static UnicodeString fromUTF32(const UChar32 *utf32, int32_t length);
3293 
3294   /* Miscellaneous operations */
3295 
3296   /**
3297    * Unescape a string of characters and return a string containing
3298    * the result.  The following escape sequences are recognized:
3299    *
3300    * \\uhhhh       4 hex digits; h in [0-9A-Fa-f]
3301    * \\Uhhhhhhhh   8 hex digits
3302    * \\xhh         1-2 hex digits
3303    * \\ooo         1-3 octal digits; o in [0-7]
3304    * \\cX          control-X; X is masked with 0x1F
3305    *
3306    * as well as the standard ANSI C escapes:
3307    *
3308    * \\a => U+0007, \\b => U+0008, \\t => U+0009, \\n => U+000A,
3309    * \\v => U+000B, \\f => U+000C, \\r => U+000D, \\e => U+001B,
3310    * \\&quot; => U+0022, \\' => U+0027, \\? => U+003F, \\\\ => U+005C
3311    *
3312    * Anything else following a backslash is generically escaped.  For
3313    * example, "[a\\-z]" returns "[a-z]".
3314    *
3315    * If an escape sequence is ill-formed, this method returns an empty
3316    * string.  An example of an ill-formed sequence is "\\u" followed by
3317    * fewer than 4 hex digits.
3318    *
3319    * This function is similar to u_unescape() but not identical to it.
3320    * The latter takes a source char*, so it does escape recognition
3321    * and also invariant conversion.
3322    *
3323    * @return a string with backslash escapes interpreted, or an
3324    * empty string on error.
3325    * @see UnicodeString#unescapeAt()
3326    * @see u_unescape()
3327    * @see u_unescapeAt()
3328    * @stable ICU 2.0
3329    */
3330   UnicodeString unescape() const;
3331 
3332   /**
3333    * Unescape a single escape sequence and return the represented
3334    * character.  See unescape() for a listing of the recognized escape
3335    * sequences.  The character at offset-1 is assumed (without
3336    * checking) to be a backslash.  If the escape sequence is
3337    * ill-formed, or the offset is out of range, U_SENTINEL=-1 is
3338    * returned.
3339    *
3340    * @param offset an input output parameter.  On input, it is the
3341    * offset into this string where the escape sequence is located,
3342    * after the initial backslash.  On output, it is advanced after the
3343    * last character parsed.  On error, it is not advanced at all.
3344    * @return the character represented by the escape sequence at
3345    * offset, or U_SENTINEL=-1 on error.
3346    * @see UnicodeString#unescape()
3347    * @see u_unescape()
3348    * @see u_unescapeAt()
3349    * @stable ICU 2.0
3350    */
3351   UChar32 unescapeAt(int32_t &offset) const;
3352 
3353   /**
3354    * ICU "poor man's RTTI", returns a UClassID for this class.
3355    *
3356    * @stable ICU 2.2
3357    */
3358   static UClassID U_EXPORT2 getStaticClassID();
3359 
3360   /**
3361    * ICU "poor man's RTTI", returns a UClassID for the actual class.
3362    *
3363    * @stable ICU 2.2
3364    */
3365   virtual UClassID getDynamicClassID() const;
3366 
3367   //========================================
3368   // Implementation methods
3369   //========================================
3370 
3371 protected:
3372   /**
3373    * Implement Replaceable::getLength() (see jitterbug 1027).
3374    * @stable ICU 2.4
3375    */
3376   virtual int32_t getLength() const;
3377 
3378   /**
3379    * The change in Replaceable to use virtual getCharAt() allows
3380    * UnicodeString::charAt() to be inline again (see jitterbug 709).
3381    * @stable ICU 2.4
3382    */
3383   virtual UChar getCharAt(int32_t offset) const;
3384 
3385   /**
3386    * The change in Replaceable to use virtual getChar32At() allows
3387    * UnicodeString::char32At() to be inline again (see jitterbug 709).
3388    * @stable ICU 2.4
3389    */
3390   virtual UChar32 getChar32At(int32_t offset) const;
3391 
3392 private:
3393   // For char* constructors. Could be made public.
3394   UnicodeString &setToUTF8(StringPiece utf8);
3395   // For extract(char*).
3396   // We could make a toUTF8(target, capacity, errorCode) public but not
3397   // this version: New API will be cleaner if we make callers create substrings
3398   // rather than having start+length on every method,
3399   // and it should take a UErrorCode&.
3400   int32_t
3401   toUTF8(int32_t start, int32_t len,
3402          char *target, int32_t capacity) const;
3403 
3404   /**
3405    * Internal string contents comparison, called by operator==.
3406    * Requires: this & text not bogus and have same lengths.
3407    */
3408   UBool doEquals(const UnicodeString &text, int32_t len) const;
3409 
3410   inline int8_t
3411   doCompare(int32_t start,
3412            int32_t length,
3413            const UnicodeString& srcText,
3414            int32_t srcStart,
3415            int32_t srcLength) const;
3416 
3417   int8_t doCompare(int32_t start,
3418            int32_t length,
3419            const UChar *srcChars,
3420            int32_t srcStart,
3421            int32_t srcLength) const;
3422 
3423   inline int8_t
3424   doCompareCodePointOrder(int32_t start,
3425                           int32_t length,
3426                           const UnicodeString& srcText,
3427                           int32_t srcStart,
3428                           int32_t srcLength) const;
3429 
3430   int8_t doCompareCodePointOrder(int32_t start,
3431                                  int32_t length,
3432                                  const UChar *srcChars,
3433                                  int32_t srcStart,
3434                                  int32_t srcLength) const;
3435 
3436   inline int8_t
3437   doCaseCompare(int32_t start,
3438                 int32_t length,
3439                 const UnicodeString &srcText,
3440                 int32_t srcStart,
3441                 int32_t srcLength,
3442                 uint32_t options) const;
3443 
3444   int8_t
3445   doCaseCompare(int32_t start,
3446                 int32_t length,
3447                 const UChar *srcChars,
3448                 int32_t srcStart,
3449                 int32_t srcLength,
3450                 uint32_t options) const;
3451 
3452   int32_t doIndexOf(UChar c,
3453             int32_t start,
3454             int32_t length) const;
3455 
3456   int32_t doIndexOf(UChar32 c,
3457                         int32_t start,
3458                         int32_t length) const;
3459 
3460   int32_t doLastIndexOf(UChar c,
3461                 int32_t start,
3462                 int32_t length) const;
3463 
3464   int32_t doLastIndexOf(UChar32 c,
3465                             int32_t start,
3466                             int32_t length) const;
3467 
3468   void doExtract(int32_t start,
3469          int32_t length,
3470          UChar *dst,
3471          int32_t dstStart) const;
3472 
3473   inline void doExtract(int32_t start,
3474          int32_t length,
3475          UnicodeString& target) const;
3476 
3477   inline UChar doCharAt(int32_t offset)  const;
3478 
3479   UnicodeString& doReplace(int32_t start,
3480                int32_t length,
3481                const UnicodeString& srcText,
3482                int32_t srcStart,
3483                int32_t srcLength);
3484 
3485   UnicodeString& doReplace(int32_t start,
3486                int32_t length,
3487                const UChar *srcChars,
3488                int32_t srcStart,
3489                int32_t srcLength);
3490 
3491   UnicodeString& doAppend(const UnicodeString& src, int32_t srcStart, int32_t srcLength);
3492   UnicodeString& doAppend(const UChar *srcChars, int32_t srcStart, int32_t srcLength);
3493 
3494   UnicodeString& doReverse(int32_t start,
3495                int32_t length);
3496 
3497   // calculate hash code
3498   int32_t doHashCode(void) const;
3499 
3500   // get pointer to start of array
3501   // these do not check for kOpenGetBuffer, unlike the public getBuffer() function
3502   inline UChar* getArrayStart(void);
3503   inline const UChar* getArrayStart(void) const;
3504 
3505   inline UBool hasShortLength() const;
3506   inline int32_t getShortLength() const;
3507 
3508   // A UnicodeString object (not necessarily its current buffer)
3509   // is writable unless it isBogus() or it has an "open" getBuffer(minCapacity).
3510   inline UBool isWritable() const;
3511 
3512   // Is the current buffer writable?
3513   inline UBool isBufferWritable() const;
3514 
3515   // None of the following does releaseArray().
3516   inline void setZeroLength();
3517   inline void setShortLength(int32_t len);
3518   inline void setLength(int32_t len);
3519   inline void setToEmpty();
3520   inline void setArray(UChar *array, int32_t len, int32_t capacity); // sets length but not flags
3521 
3522   // allocate the array; result may be the stack buffer
3523   // sets refCount to 1 if appropriate
3524   // sets fArray, fCapacity, and flags
3525   // sets length to 0
3526   // returns boolean for success or failure
3527   UBool allocate(int32_t capacity);
3528 
3529   // release the array if owned
3530   void releaseArray(void);
3531 
3532   // turn a bogus string into an empty one
3533   void unBogus();
3534 
3535   // implements assigment operator, copy constructor, and fastCopyFrom()
3536   UnicodeString &copyFrom(const UnicodeString &src, UBool fastCopy=FALSE);
3537 
3538   // Copies just the fields without memory management.
3539   void copyFieldsFrom(UnicodeString &src, UBool setSrcToBogus) U_NOEXCEPT;
3540 
3541   // Pin start and limit to acceptable values.
3542   inline void pinIndex(int32_t& start) const;
3543   inline void pinIndices(int32_t& start,
3544                          int32_t& length) const;
3545 
3546 #if !UCONFIG_NO_CONVERSION
3547 
3548   /* Internal extract() using UConverter. */
3549   int32_t doExtract(int32_t start, int32_t length,
3550                     char *dest, int32_t destCapacity,
3551                     UConverter *cnv,
3552                     UErrorCode &errorCode) const;
3553 
3554   /*
3555    * Real constructor for converting from codepage data.
3556    * It assumes that it is called with !fRefCounted.
3557    *
3558    * If <code>codepage==0</code>, then the default converter
3559    * is used for the platform encoding.
3560    * If <code>codepage</code> is an empty string (<code>""</code>),
3561    * then a simple conversion is performed on the codepage-invariant
3562    * subset ("invariant characters") of the platform encoding. See utypes.h.
3563    */
3564   void doCodepageCreate(const char *codepageData,
3565                         int32_t dataLength,
3566                         const char *codepage);
3567 
3568   /*
3569    * Worker function for creating a UnicodeString from
3570    * a codepage string using a UConverter.
3571    */
3572   void
3573   doCodepageCreate(const char *codepageData,
3574                    int32_t dataLength,
3575                    UConverter *converter,
3576                    UErrorCode &status);
3577 
3578 #endif
3579 
3580   /*
3581    * This function is called when write access to the array
3582    * is necessary.
3583    *
3584    * We need to make a copy of the array if
3585    * the buffer is read-only, or
3586    * the buffer is refCounted (shared), and refCount>1, or
3587    * the buffer is too small.
3588    *
3589    * Return FALSE if memory could not be allocated.
3590    */
3591   UBool cloneArrayIfNeeded(int32_t newCapacity = -1,
3592                             int32_t growCapacity = -1,
3593                             UBool doCopyArray = TRUE,
3594                             int32_t **pBufferToDelete = 0,
3595                             UBool forceClone = FALSE);
3596 
3597   /**
3598    * Common function for UnicodeString case mappings.
3599    * The stringCaseMapper has the same type UStringCaseMapper
3600    * as in ustr_imp.h for ustrcase_map().
3601    */
3602   UnicodeString &
3603   caseMap(const UCaseMap *csm, UStringCaseMapper *stringCaseMapper);
3604 
3605   // ref counting
3606   void addRef(void);
3607   int32_t removeRef(void);
3608   int32_t refCount(void) const;
3609 
3610   // constants
3611   enum {
3612     /**
3613      * Size of stack buffer for short strings.
3614      * Must be at least U16_MAX_LENGTH for the single-code point constructor to work.
3615      * @see UNISTR_OBJECT_SIZE
3616      */
3617     US_STACKBUF_SIZE=(int32_t)(UNISTR_OBJECT_SIZE-sizeof(void *)-2)/U_SIZEOF_UCHAR,
3618     kInvalidUChar=0xffff, // U+FFFF returned by charAt(invalid index)
3619     kInvalidHashCode=0, // invalid hash code
3620     kEmptyHashCode=1, // hash code for empty string
3621 
3622     // bit flag values for fLengthAndFlags
3623     kIsBogus=1,         // this string is bogus, i.e., not valid or NULL
3624     kUsingStackBuffer=2,// using fUnion.fStackFields instead of fUnion.fFields
3625     kRefCounted=4,      // there is a refCount field before the characters in fArray
3626     kBufferIsReadonly=8,// do not write to this buffer
3627     kOpenGetBuffer=16,  // getBuffer(minCapacity) was called (is "open"),
3628                         // and releaseBuffer(newLength) must be called
3629     kAllStorageFlags=0x1f,
3630 
3631     kLengthShift=5,     // remaining 11 bits for non-negative short length, or negative if long
3632     kLength1=1<<kLengthShift,
3633     kMaxShortLength=0x3ff,  // max non-negative short length (leaves top bit 0)
3634     kLengthIsLarge=0xffe0,  // short length < 0, real length is in fUnion.fFields.fLength
3635 
3636     // combined values for convenience
3637     kShortString=kUsingStackBuffer,
3638     kLongString=kRefCounted,
3639     kReadonlyAlias=kBufferIsReadonly,
3640     kWritableAlias=0
3641   };
3642 
3643   friend class UnicodeStringAppendable;
3644 
3645   union StackBufferOrFields;        // forward declaration necessary before friend declaration
3646   friend union StackBufferOrFields; // make US_STACKBUF_SIZE visible inside fUnion
3647 
3648   /*
3649    * The following are all the class fields that are stored
3650    * in each UnicodeString object.
3651    * Note that UnicodeString has virtual functions,
3652    * therefore there is an implicit vtable pointer
3653    * as the first real field.
3654    * The fields should be aligned such that no padding is necessary.
3655    * On 32-bit machines, the size should be 32 bytes,
3656    * on 64-bit machines (8-byte pointers), it should be 40 bytes.
3657    *
3658    * We use a hack to achieve this.
3659    *
3660    * With at least some compilers, each of the following is forced to
3661    * a multiple of sizeof(pointer) [the largest field base unit here is a data pointer],
3662    * rounded up with additional padding if the fields do not already fit that requirement:
3663    * - sizeof(class UnicodeString)
3664    * - offsetof(UnicodeString, fUnion)
3665    * - sizeof(fUnion)
3666    * - sizeof(fStackFields)
3667    *
3668    * We optimize for the longest possible internal buffer for short strings.
3669    * fUnion.fStackFields begins with 2 bytes for storage flags
3670    * and the length of relatively short strings,
3671    * followed by the buffer for short string contents.
3672    * There is no padding inside fStackFields.
3673    *
3674    * Heap-allocated and aliased strings use fUnion.fFields.
3675    * Both fStackFields and fFields must begin with the same fields for flags and short length,
3676    * that is, those must have the same memory offsets inside the object,
3677    * because the flags must be inspected in order to decide which half of fUnion is being used.
3678    * We assume that the compiler does not reorder the fields.
3679    *
3680    * (Padding at the end of fFields is ok:
3681    * As long as it is no larger than fStackFields, it is not wasted space.)
3682    *
3683    * For some of the history of the UnicodeString class fields layout, see
3684    * - ICU ticket #11551 "longer UnicodeString contents in stack buffer"
3685    * - ICU ticket #11336 "UnicodeString: recombine stack buffer arrays"
3686    * - ICU ticket #8322 "why is sizeof(UnicodeString)==48?"
3687    */
3688   // (implicit) *vtable;
3689   union StackBufferOrFields {
3690     // fStackFields is used iff (fLengthAndFlags&kUsingStackBuffer) else fFields is used.
3691     // Each struct of the union must begin with fLengthAndFlags.
3692     struct {
3693       int16_t fLengthAndFlags;          // bit fields: see constants above
3694       UChar fBuffer[US_STACKBUF_SIZE];  // buffer for short strings
3695     } fStackFields;
3696     struct {
3697       int16_t fLengthAndFlags;          // bit fields: see constants above
3698       int32_t fLength;    // number of characters in fArray if >127; else undefined
3699       int32_t fCapacity;  // capacity of fArray (in UChars)
3700       // array pointer last to minimize padding for machines with P128 data model
3701       // or pointer sizes that are not a power of 2
3702       UChar   *fArray;    // the Unicode data
3703     } fFields;
3704   } fUnion;
3705 };
3706 
3707 /**
3708  * Create a new UnicodeString with the concatenation of two others.
3709  *
3710  * @param s1 The first string to be copied to the new one.
3711  * @param s2 The second string to be copied to the new one, after s1.
3712  * @return UnicodeString(s1).append(s2)
3713  * @stable ICU 2.8
3714  */
3715 U_COMMON_API UnicodeString U_EXPORT2
3716 operator+ (const UnicodeString &s1, const UnicodeString &s2);
3717 
3718 //========================================
3719 // Inline members
3720 //========================================
3721 
3722 //========================================
3723 // Privates
3724 //========================================
3725 
3726 inline void
pinIndex(int32_t & start)3727 UnicodeString::pinIndex(int32_t& start) const
3728 {
3729   // pin index
3730   if(start < 0) {
3731     start = 0;
3732   } else if(start > length()) {
3733     start = length();
3734   }
3735 }
3736 
3737 inline void
pinIndices(int32_t & start,int32_t & _length)3738 UnicodeString::pinIndices(int32_t& start,
3739                           int32_t& _length) const
3740 {
3741   // pin indices
3742   int32_t len = length();
3743   if(start < 0) {
3744     start = 0;
3745   } else if(start > len) {
3746     start = len;
3747   }
3748   if(_length < 0) {
3749     _length = 0;
3750   } else if(_length > (len - start)) {
3751     _length = (len - start);
3752   }
3753 }
3754 
3755 inline UChar*
getArrayStart()3756 UnicodeString::getArrayStart() {
3757   return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
3758     fUnion.fStackFields.fBuffer : fUnion.fFields.fArray;
3759 }
3760 
3761 inline const UChar*
getArrayStart()3762 UnicodeString::getArrayStart() const {
3763   return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
3764     fUnion.fStackFields.fBuffer : fUnion.fFields.fArray;
3765 }
3766 
3767 //========================================
3768 // Default constructor
3769 //========================================
3770 
3771 inline
UnicodeString()3772 UnicodeString::UnicodeString() {
3773   fUnion.fStackFields.fLengthAndFlags=kShortString;
3774 }
3775 
3776 //========================================
3777 // Read-only implementation methods
3778 //========================================
3779 inline UBool
hasShortLength()3780 UnicodeString::hasShortLength() const {
3781   return fUnion.fFields.fLengthAndFlags>=0;
3782 }
3783 
3784 inline int32_t
getShortLength()3785 UnicodeString::getShortLength() const {
3786   // fLengthAndFlags must be non-negative -> short length >= 0
3787   // and arithmetic or logical shift does not matter.
3788   return fUnion.fFields.fLengthAndFlags>>kLengthShift;
3789 }
3790 
3791 inline int32_t
length()3792 UnicodeString::length() const {
3793   return hasShortLength() ? getShortLength() : fUnion.fFields.fLength;
3794 }
3795 
3796 inline int32_t
getCapacity()3797 UnicodeString::getCapacity() const {
3798   return (fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) ?
3799     US_STACKBUF_SIZE : fUnion.fFields.fCapacity;
3800 }
3801 
3802 inline int32_t
hashCode()3803 UnicodeString::hashCode() const
3804 { return doHashCode(); }
3805 
3806 inline UBool
isBogus()3807 UnicodeString::isBogus() const
3808 { return (UBool)(fUnion.fFields.fLengthAndFlags & kIsBogus); }
3809 
3810 inline UBool
isWritable()3811 UnicodeString::isWritable() const
3812 { return (UBool)!(fUnion.fFields.fLengthAndFlags&(kOpenGetBuffer|kIsBogus)); }
3813 
3814 inline UBool
isBufferWritable()3815 UnicodeString::isBufferWritable() const
3816 {
3817   return (UBool)(
3818       !(fUnion.fFields.fLengthAndFlags&(kOpenGetBuffer|kIsBogus|kBufferIsReadonly)) &&
3819       (!(fUnion.fFields.fLengthAndFlags&kRefCounted) || refCount()==1));
3820 }
3821 
3822 inline const UChar *
getBuffer()3823 UnicodeString::getBuffer() const {
3824   if(fUnion.fFields.fLengthAndFlags&(kIsBogus|kOpenGetBuffer)) {
3825     return 0;
3826   } else if(fUnion.fFields.fLengthAndFlags&kUsingStackBuffer) {
3827     return fUnion.fStackFields.fBuffer;
3828   } else {
3829     return fUnion.fFields.fArray;
3830   }
3831 }
3832 
3833 //========================================
3834 // Read-only alias methods
3835 //========================================
3836 inline int8_t
doCompare(int32_t start,int32_t thisLength,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)3837 UnicodeString::doCompare(int32_t start,
3838               int32_t thisLength,
3839               const UnicodeString& srcText,
3840               int32_t srcStart,
3841               int32_t srcLength) const
3842 {
3843   if(srcText.isBogus()) {
3844     return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
3845   } else {
3846     srcText.pinIndices(srcStart, srcLength);
3847     return doCompare(start, thisLength, srcText.getArrayStart(), srcStart, srcLength);
3848   }
3849 }
3850 
3851 inline UBool
3852 UnicodeString::operator== (const UnicodeString& text) const
3853 {
3854   if(isBogus()) {
3855     return text.isBogus();
3856   } else {
3857     int32_t len = length(), textLength = text.length();
3858     return !text.isBogus() && len == textLength && doEquals(text, len);
3859   }
3860 }
3861 
3862 inline UBool
3863 UnicodeString::operator!= (const UnicodeString& text) const
3864 { return (! operator==(text)); }
3865 
3866 inline UBool
3867 UnicodeString::operator> (const UnicodeString& text) const
3868 { return doCompare(0, length(), text, 0, text.length()) == 1; }
3869 
3870 inline UBool
3871 UnicodeString::operator< (const UnicodeString& text) const
3872 { return doCompare(0, length(), text, 0, text.length()) == -1; }
3873 
3874 inline UBool
3875 UnicodeString::operator>= (const UnicodeString& text) const
3876 { return doCompare(0, length(), text, 0, text.length()) != -1; }
3877 
3878 inline UBool
3879 UnicodeString::operator<= (const UnicodeString& text) const
3880 { return doCompare(0, length(), text, 0, text.length()) != 1; }
3881 
3882 inline int8_t
compare(const UnicodeString & text)3883 UnicodeString::compare(const UnicodeString& text) const
3884 { return doCompare(0, length(), text, 0, text.length()); }
3885 
3886 inline int8_t
compare(int32_t start,int32_t _length,const UnicodeString & srcText)3887 UnicodeString::compare(int32_t start,
3888                int32_t _length,
3889                const UnicodeString& srcText) const
3890 { return doCompare(start, _length, srcText, 0, srcText.length()); }
3891 
3892 inline int8_t
compare(const UChar * srcChars,int32_t srcLength)3893 UnicodeString::compare(const UChar *srcChars,
3894                int32_t srcLength) const
3895 { return doCompare(0, length(), srcChars, 0, srcLength); }
3896 
3897 inline int8_t
compare(int32_t start,int32_t _length,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)3898 UnicodeString::compare(int32_t start,
3899                int32_t _length,
3900                const UnicodeString& srcText,
3901                int32_t srcStart,
3902                int32_t srcLength) const
3903 { return doCompare(start, _length, srcText, srcStart, srcLength); }
3904 
3905 inline int8_t
compare(int32_t start,int32_t _length,const UChar * srcChars)3906 UnicodeString::compare(int32_t start,
3907                int32_t _length,
3908                const UChar *srcChars) const
3909 { return doCompare(start, _length, srcChars, 0, _length); }
3910 
3911 inline int8_t
compare(int32_t start,int32_t _length,const UChar * srcChars,int32_t srcStart,int32_t srcLength)3912 UnicodeString::compare(int32_t start,
3913                int32_t _length,
3914                const UChar *srcChars,
3915                int32_t srcStart,
3916                int32_t srcLength) const
3917 { return doCompare(start, _length, srcChars, srcStart, srcLength); }
3918 
3919 inline int8_t
compareBetween(int32_t start,int32_t limit,const UnicodeString & srcText,int32_t srcStart,int32_t srcLimit)3920 UnicodeString::compareBetween(int32_t start,
3921                   int32_t limit,
3922                   const UnicodeString& srcText,
3923                   int32_t srcStart,
3924                   int32_t srcLimit) const
3925 { return doCompare(start, limit - start,
3926            srcText, srcStart, srcLimit - srcStart); }
3927 
3928 inline int8_t
doCompareCodePointOrder(int32_t start,int32_t thisLength,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)3929 UnicodeString::doCompareCodePointOrder(int32_t start,
3930                                        int32_t thisLength,
3931                                        const UnicodeString& srcText,
3932                                        int32_t srcStart,
3933                                        int32_t srcLength) const
3934 {
3935   if(srcText.isBogus()) {
3936     return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
3937   } else {
3938     srcText.pinIndices(srcStart, srcLength);
3939     return doCompareCodePointOrder(start, thisLength, srcText.getArrayStart(), srcStart, srcLength);
3940   }
3941 }
3942 
3943 inline int8_t
compareCodePointOrder(const UnicodeString & text)3944 UnicodeString::compareCodePointOrder(const UnicodeString& text) const
3945 { return doCompareCodePointOrder(0, length(), text, 0, text.length()); }
3946 
3947 inline int8_t
compareCodePointOrder(int32_t start,int32_t _length,const UnicodeString & srcText)3948 UnicodeString::compareCodePointOrder(int32_t start,
3949                                      int32_t _length,
3950                                      const UnicodeString& srcText) const
3951 { return doCompareCodePointOrder(start, _length, srcText, 0, srcText.length()); }
3952 
3953 inline int8_t
compareCodePointOrder(const UChar * srcChars,int32_t srcLength)3954 UnicodeString::compareCodePointOrder(const UChar *srcChars,
3955                                      int32_t srcLength) const
3956 { return doCompareCodePointOrder(0, length(), srcChars, 0, srcLength); }
3957 
3958 inline int8_t
compareCodePointOrder(int32_t start,int32_t _length,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)3959 UnicodeString::compareCodePointOrder(int32_t start,
3960                                      int32_t _length,
3961                                      const UnicodeString& srcText,
3962                                      int32_t srcStart,
3963                                      int32_t srcLength) const
3964 { return doCompareCodePointOrder(start, _length, srcText, srcStart, srcLength); }
3965 
3966 inline int8_t
compareCodePointOrder(int32_t start,int32_t _length,const UChar * srcChars)3967 UnicodeString::compareCodePointOrder(int32_t start,
3968                                      int32_t _length,
3969                                      const UChar *srcChars) const
3970 { return doCompareCodePointOrder(start, _length, srcChars, 0, _length); }
3971 
3972 inline int8_t
compareCodePointOrder(int32_t start,int32_t _length,const UChar * srcChars,int32_t srcStart,int32_t srcLength)3973 UnicodeString::compareCodePointOrder(int32_t start,
3974                                      int32_t _length,
3975                                      const UChar *srcChars,
3976                                      int32_t srcStart,
3977                                      int32_t srcLength) const
3978 { return doCompareCodePointOrder(start, _length, srcChars, srcStart, srcLength); }
3979 
3980 inline int8_t
compareCodePointOrderBetween(int32_t start,int32_t limit,const UnicodeString & srcText,int32_t srcStart,int32_t srcLimit)3981 UnicodeString::compareCodePointOrderBetween(int32_t start,
3982                                             int32_t limit,
3983                                             const UnicodeString& srcText,
3984                                             int32_t srcStart,
3985                                             int32_t srcLimit) const
3986 { return doCompareCodePointOrder(start, limit - start,
3987            srcText, srcStart, srcLimit - srcStart); }
3988 
3989 inline int8_t
doCaseCompare(int32_t start,int32_t thisLength,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength,uint32_t options)3990 UnicodeString::doCaseCompare(int32_t start,
3991                              int32_t thisLength,
3992                              const UnicodeString &srcText,
3993                              int32_t srcStart,
3994                              int32_t srcLength,
3995                              uint32_t options) const
3996 {
3997   if(srcText.isBogus()) {
3998     return (int8_t)!isBogus(); // 0 if both are bogus, 1 otherwise
3999   } else {
4000     srcText.pinIndices(srcStart, srcLength);
4001     return doCaseCompare(start, thisLength, srcText.getArrayStart(), srcStart, srcLength, options);
4002   }
4003 }
4004 
4005 inline int8_t
caseCompare(const UnicodeString & text,uint32_t options)4006 UnicodeString::caseCompare(const UnicodeString &text, uint32_t options) const {
4007   return doCaseCompare(0, length(), text, 0, text.length(), options);
4008 }
4009 
4010 inline int8_t
caseCompare(int32_t start,int32_t _length,const UnicodeString & srcText,uint32_t options)4011 UnicodeString::caseCompare(int32_t start,
4012                            int32_t _length,
4013                            const UnicodeString &srcText,
4014                            uint32_t options) const {
4015   return doCaseCompare(start, _length, srcText, 0, srcText.length(), options);
4016 }
4017 
4018 inline int8_t
caseCompare(const UChar * srcChars,int32_t srcLength,uint32_t options)4019 UnicodeString::caseCompare(const UChar *srcChars,
4020                            int32_t srcLength,
4021                            uint32_t options) const {
4022   return doCaseCompare(0, length(), srcChars, 0, srcLength, options);
4023 }
4024 
4025 inline int8_t
caseCompare(int32_t start,int32_t _length,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength,uint32_t options)4026 UnicodeString::caseCompare(int32_t start,
4027                            int32_t _length,
4028                            const UnicodeString &srcText,
4029                            int32_t srcStart,
4030                            int32_t srcLength,
4031                            uint32_t options) const {
4032   return doCaseCompare(start, _length, srcText, srcStart, srcLength, options);
4033 }
4034 
4035 inline int8_t
caseCompare(int32_t start,int32_t _length,const UChar * srcChars,uint32_t options)4036 UnicodeString::caseCompare(int32_t start,
4037                            int32_t _length,
4038                            const UChar *srcChars,
4039                            uint32_t options) const {
4040   return doCaseCompare(start, _length, srcChars, 0, _length, options);
4041 }
4042 
4043 inline int8_t
caseCompare(int32_t start,int32_t _length,const UChar * srcChars,int32_t srcStart,int32_t srcLength,uint32_t options)4044 UnicodeString::caseCompare(int32_t start,
4045                            int32_t _length,
4046                            const UChar *srcChars,
4047                            int32_t srcStart,
4048                            int32_t srcLength,
4049                            uint32_t options) const {
4050   return doCaseCompare(start, _length, srcChars, srcStart, srcLength, options);
4051 }
4052 
4053 inline int8_t
caseCompareBetween(int32_t start,int32_t limit,const UnicodeString & srcText,int32_t srcStart,int32_t srcLimit,uint32_t options)4054 UnicodeString::caseCompareBetween(int32_t start,
4055                                   int32_t limit,
4056                                   const UnicodeString &srcText,
4057                                   int32_t srcStart,
4058                                   int32_t srcLimit,
4059                                   uint32_t options) const {
4060   return doCaseCompare(start, limit - start, srcText, srcStart, srcLimit - srcStart, options);
4061 }
4062 
4063 inline int32_t
indexOf(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength,int32_t start,int32_t _length)4064 UnicodeString::indexOf(const UnicodeString& srcText,
4065                int32_t srcStart,
4066                int32_t srcLength,
4067                int32_t start,
4068                int32_t _length) const
4069 {
4070   if(!srcText.isBogus()) {
4071     srcText.pinIndices(srcStart, srcLength);
4072     if(srcLength > 0) {
4073       return indexOf(srcText.getArrayStart(), srcStart, srcLength, start, _length);
4074     }
4075   }
4076   return -1;
4077 }
4078 
4079 inline int32_t
indexOf(const UnicodeString & text)4080 UnicodeString::indexOf(const UnicodeString& text) const
4081 { return indexOf(text, 0, text.length(), 0, length()); }
4082 
4083 inline int32_t
indexOf(const UnicodeString & text,int32_t start)4084 UnicodeString::indexOf(const UnicodeString& text,
4085                int32_t start) const {
4086   pinIndex(start);
4087   return indexOf(text, 0, text.length(), start, length() - start);
4088 }
4089 
4090 inline int32_t
indexOf(const UnicodeString & text,int32_t start,int32_t _length)4091 UnicodeString::indexOf(const UnicodeString& text,
4092                int32_t start,
4093                int32_t _length) const
4094 { return indexOf(text, 0, text.length(), start, _length); }
4095 
4096 inline int32_t
indexOf(const UChar * srcChars,int32_t srcLength,int32_t start)4097 UnicodeString::indexOf(const UChar *srcChars,
4098                int32_t srcLength,
4099                int32_t start) const {
4100   pinIndex(start);
4101   return indexOf(srcChars, 0, srcLength, start, length() - start);
4102 }
4103 
4104 inline int32_t
indexOf(const UChar * srcChars,int32_t srcLength,int32_t start,int32_t _length)4105 UnicodeString::indexOf(const UChar *srcChars,
4106                int32_t srcLength,
4107                int32_t start,
4108                int32_t _length) const
4109 { return indexOf(srcChars, 0, srcLength, start, _length); }
4110 
4111 inline int32_t
indexOf(UChar c,int32_t start,int32_t _length)4112 UnicodeString::indexOf(UChar c,
4113                int32_t start,
4114                int32_t _length) const
4115 { return doIndexOf(c, start, _length); }
4116 
4117 inline int32_t
indexOf(UChar32 c,int32_t start,int32_t _length)4118 UnicodeString::indexOf(UChar32 c,
4119                int32_t start,
4120                int32_t _length) const
4121 { return doIndexOf(c, start, _length); }
4122 
4123 inline int32_t
indexOf(UChar c)4124 UnicodeString::indexOf(UChar c) const
4125 { return doIndexOf(c, 0, length()); }
4126 
4127 inline int32_t
indexOf(UChar32 c)4128 UnicodeString::indexOf(UChar32 c) const
4129 { return indexOf(c, 0, length()); }
4130 
4131 inline int32_t
indexOf(UChar c,int32_t start)4132 UnicodeString::indexOf(UChar c,
4133                int32_t start) const {
4134   pinIndex(start);
4135   return doIndexOf(c, start, length() - start);
4136 }
4137 
4138 inline int32_t
indexOf(UChar32 c,int32_t start)4139 UnicodeString::indexOf(UChar32 c,
4140                int32_t start) const {
4141   pinIndex(start);
4142   return indexOf(c, start, length() - start);
4143 }
4144 
4145 inline int32_t
lastIndexOf(const UChar * srcChars,int32_t srcLength,int32_t start,int32_t _length)4146 UnicodeString::lastIndexOf(const UChar *srcChars,
4147                int32_t srcLength,
4148                int32_t start,
4149                int32_t _length) const
4150 { return lastIndexOf(srcChars, 0, srcLength, start, _length); }
4151 
4152 inline int32_t
lastIndexOf(const UChar * srcChars,int32_t srcLength,int32_t start)4153 UnicodeString::lastIndexOf(const UChar *srcChars,
4154                int32_t srcLength,
4155                int32_t start) const {
4156   pinIndex(start);
4157   return lastIndexOf(srcChars, 0, srcLength, start, length() - start);
4158 }
4159 
4160 inline int32_t
lastIndexOf(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength,int32_t start,int32_t _length)4161 UnicodeString::lastIndexOf(const UnicodeString& srcText,
4162                int32_t srcStart,
4163                int32_t srcLength,
4164                int32_t start,
4165                int32_t _length) const
4166 {
4167   if(!srcText.isBogus()) {
4168     srcText.pinIndices(srcStart, srcLength);
4169     if(srcLength > 0) {
4170       return lastIndexOf(srcText.getArrayStart(), srcStart, srcLength, start, _length);
4171     }
4172   }
4173   return -1;
4174 }
4175 
4176 inline int32_t
lastIndexOf(const UnicodeString & text,int32_t start,int32_t _length)4177 UnicodeString::lastIndexOf(const UnicodeString& text,
4178                int32_t start,
4179                int32_t _length) const
4180 { return lastIndexOf(text, 0, text.length(), start, _length); }
4181 
4182 inline int32_t
lastIndexOf(const UnicodeString & text,int32_t start)4183 UnicodeString::lastIndexOf(const UnicodeString& text,
4184                int32_t start) const {
4185   pinIndex(start);
4186   return lastIndexOf(text, 0, text.length(), start, length() - start);
4187 }
4188 
4189 inline int32_t
lastIndexOf(const UnicodeString & text)4190 UnicodeString::lastIndexOf(const UnicodeString& text) const
4191 { return lastIndexOf(text, 0, text.length(), 0, length()); }
4192 
4193 inline int32_t
lastIndexOf(UChar c,int32_t start,int32_t _length)4194 UnicodeString::lastIndexOf(UChar c,
4195                int32_t start,
4196                int32_t _length) const
4197 { return doLastIndexOf(c, start, _length); }
4198 
4199 inline int32_t
lastIndexOf(UChar32 c,int32_t start,int32_t _length)4200 UnicodeString::lastIndexOf(UChar32 c,
4201                int32_t start,
4202                int32_t _length) const {
4203   return doLastIndexOf(c, start, _length);
4204 }
4205 
4206 inline int32_t
lastIndexOf(UChar c)4207 UnicodeString::lastIndexOf(UChar c) const
4208 { return doLastIndexOf(c, 0, length()); }
4209 
4210 inline int32_t
lastIndexOf(UChar32 c)4211 UnicodeString::lastIndexOf(UChar32 c) const {
4212   return lastIndexOf(c, 0, length());
4213 }
4214 
4215 inline int32_t
lastIndexOf(UChar c,int32_t start)4216 UnicodeString::lastIndexOf(UChar c,
4217                int32_t start) const {
4218   pinIndex(start);
4219   return doLastIndexOf(c, start, length() - start);
4220 }
4221 
4222 inline int32_t
lastIndexOf(UChar32 c,int32_t start)4223 UnicodeString::lastIndexOf(UChar32 c,
4224                int32_t start) const {
4225   pinIndex(start);
4226   return lastIndexOf(c, start, length() - start);
4227 }
4228 
4229 inline UBool
startsWith(const UnicodeString & text)4230 UnicodeString::startsWith(const UnicodeString& text) const
4231 { return compare(0, text.length(), text, 0, text.length()) == 0; }
4232 
4233 inline UBool
startsWith(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4234 UnicodeString::startsWith(const UnicodeString& srcText,
4235               int32_t srcStart,
4236               int32_t srcLength) const
4237 { return doCompare(0, srcLength, srcText, srcStart, srcLength) == 0; }
4238 
4239 inline UBool
startsWith(const UChar * srcChars,int32_t srcLength)4240 UnicodeString::startsWith(const UChar *srcChars, int32_t srcLength) const {
4241   if(srcLength < 0) {
4242     srcLength = u_strlen(srcChars);
4243   }
4244   return doCompare(0, srcLength, srcChars, 0, srcLength) == 0;
4245 }
4246 
4247 inline UBool
startsWith(const UChar * srcChars,int32_t srcStart,int32_t srcLength)4248 UnicodeString::startsWith(const UChar *srcChars, int32_t srcStart, int32_t srcLength) const {
4249   if(srcLength < 0) {
4250     srcLength = u_strlen(srcChars);
4251   }
4252   return doCompare(0, srcLength, srcChars, srcStart, srcLength) == 0;
4253 }
4254 
4255 inline UBool
endsWith(const UnicodeString & text)4256 UnicodeString::endsWith(const UnicodeString& text) const
4257 { return doCompare(length() - text.length(), text.length(),
4258            text, 0, text.length()) == 0; }
4259 
4260 inline UBool
endsWith(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4261 UnicodeString::endsWith(const UnicodeString& srcText,
4262             int32_t srcStart,
4263             int32_t srcLength) const {
4264   srcText.pinIndices(srcStart, srcLength);
4265   return doCompare(length() - srcLength, srcLength,
4266                    srcText, srcStart, srcLength) == 0;
4267 }
4268 
4269 inline UBool
endsWith(const UChar * srcChars,int32_t srcLength)4270 UnicodeString::endsWith(const UChar *srcChars,
4271             int32_t srcLength) const {
4272   if(srcLength < 0) {
4273     srcLength = u_strlen(srcChars);
4274   }
4275   return doCompare(length() - srcLength, srcLength,
4276                    srcChars, 0, srcLength) == 0;
4277 }
4278 
4279 inline UBool
endsWith(const UChar * srcChars,int32_t srcStart,int32_t srcLength)4280 UnicodeString::endsWith(const UChar *srcChars,
4281             int32_t srcStart,
4282             int32_t srcLength) const {
4283   if(srcLength < 0) {
4284     srcLength = u_strlen(srcChars + srcStart);
4285   }
4286   return doCompare(length() - srcLength, srcLength,
4287                    srcChars, srcStart, srcLength) == 0;
4288 }
4289 
4290 //========================================
4291 // replace
4292 //========================================
4293 inline UnicodeString&
replace(int32_t start,int32_t _length,const UnicodeString & srcText)4294 UnicodeString::replace(int32_t start,
4295                int32_t _length,
4296                const UnicodeString& srcText)
4297 { return doReplace(start, _length, srcText, 0, srcText.length()); }
4298 
4299 inline UnicodeString&
replace(int32_t start,int32_t _length,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4300 UnicodeString::replace(int32_t start,
4301                int32_t _length,
4302                const UnicodeString& srcText,
4303                int32_t srcStart,
4304                int32_t srcLength)
4305 { return doReplace(start, _length, srcText, srcStart, srcLength); }
4306 
4307 inline UnicodeString&
replace(int32_t start,int32_t _length,const UChar * srcChars,int32_t srcLength)4308 UnicodeString::replace(int32_t start,
4309                int32_t _length,
4310                const UChar *srcChars,
4311                int32_t srcLength)
4312 { return doReplace(start, _length, srcChars, 0, srcLength); }
4313 
4314 inline UnicodeString&
replace(int32_t start,int32_t _length,const UChar * srcChars,int32_t srcStart,int32_t srcLength)4315 UnicodeString::replace(int32_t start,
4316                int32_t _length,
4317                const UChar *srcChars,
4318                int32_t srcStart,
4319                int32_t srcLength)
4320 { return doReplace(start, _length, srcChars, srcStart, srcLength); }
4321 
4322 inline UnicodeString&
replace(int32_t start,int32_t _length,UChar srcChar)4323 UnicodeString::replace(int32_t start,
4324                int32_t _length,
4325                UChar srcChar)
4326 { return doReplace(start, _length, &srcChar, 0, 1); }
4327 
4328 inline UnicodeString&
replaceBetween(int32_t start,int32_t limit,const UnicodeString & srcText)4329 UnicodeString::replaceBetween(int32_t start,
4330                   int32_t limit,
4331                   const UnicodeString& srcText)
4332 { return doReplace(start, limit - start, srcText, 0, srcText.length()); }
4333 
4334 inline UnicodeString&
replaceBetween(int32_t start,int32_t limit,const UnicodeString & srcText,int32_t srcStart,int32_t srcLimit)4335 UnicodeString::replaceBetween(int32_t start,
4336                   int32_t limit,
4337                   const UnicodeString& srcText,
4338                   int32_t srcStart,
4339                   int32_t srcLimit)
4340 { return doReplace(start, limit - start, srcText, srcStart, srcLimit - srcStart); }
4341 
4342 inline UnicodeString&
findAndReplace(const UnicodeString & oldText,const UnicodeString & newText)4343 UnicodeString::findAndReplace(const UnicodeString& oldText,
4344                   const UnicodeString& newText)
4345 { return findAndReplace(0, length(), oldText, 0, oldText.length(),
4346             newText, 0, newText.length()); }
4347 
4348 inline UnicodeString&
findAndReplace(int32_t start,int32_t _length,const UnicodeString & oldText,const UnicodeString & newText)4349 UnicodeString::findAndReplace(int32_t start,
4350                   int32_t _length,
4351                   const UnicodeString& oldText,
4352                   const UnicodeString& newText)
4353 { return findAndReplace(start, _length, oldText, 0, oldText.length(),
4354             newText, 0, newText.length()); }
4355 
4356 // ============================
4357 // extract
4358 // ============================
4359 inline void
doExtract(int32_t start,int32_t _length,UnicodeString & target)4360 UnicodeString::doExtract(int32_t start,
4361              int32_t _length,
4362              UnicodeString& target) const
4363 { target.replace(0, target.length(), *this, start, _length); }
4364 
4365 inline void
extract(int32_t start,int32_t _length,UChar * target,int32_t targetStart)4366 UnicodeString::extract(int32_t start,
4367                int32_t _length,
4368                UChar *target,
4369                int32_t targetStart) const
4370 { doExtract(start, _length, target, targetStart); }
4371 
4372 inline void
extract(int32_t start,int32_t _length,UnicodeString & target)4373 UnicodeString::extract(int32_t start,
4374                int32_t _length,
4375                UnicodeString& target) const
4376 { doExtract(start, _length, target); }
4377 
4378 #if !UCONFIG_NO_CONVERSION
4379 
4380 inline int32_t
extract(int32_t start,int32_t _length,char * dst,const char * codepage)4381 UnicodeString::extract(int32_t start,
4382                int32_t _length,
4383                char *dst,
4384                const char *codepage) const
4385 
4386 {
4387   // This dstSize value will be checked explicitly
4388   return extract(start, _length, dst, dst!=0 ? 0xffffffff : 0, codepage);
4389 }
4390 
4391 #endif
4392 
4393 inline void
extractBetween(int32_t start,int32_t limit,UChar * dst,int32_t dstStart)4394 UnicodeString::extractBetween(int32_t start,
4395                   int32_t limit,
4396                   UChar *dst,
4397                   int32_t dstStart) const {
4398   pinIndex(start);
4399   pinIndex(limit);
4400   doExtract(start, limit - start, dst, dstStart);
4401 }
4402 
4403 inline UnicodeString
tempSubStringBetween(int32_t start,int32_t limit)4404 UnicodeString::tempSubStringBetween(int32_t start, int32_t limit) const {
4405     return tempSubString(start, limit - start);
4406 }
4407 
4408 inline UChar
doCharAt(int32_t offset)4409 UnicodeString::doCharAt(int32_t offset) const
4410 {
4411   if((uint32_t)offset < (uint32_t)length()) {
4412     return getArrayStart()[offset];
4413   } else {
4414     return kInvalidUChar;
4415   }
4416 }
4417 
4418 inline UChar
charAt(int32_t offset)4419 UnicodeString::charAt(int32_t offset) const
4420 { return doCharAt(offset); }
4421 
4422 inline UChar
4423 UnicodeString::operator[] (int32_t offset) const
4424 { return doCharAt(offset); }
4425 
4426 inline UBool
isEmpty()4427 UnicodeString::isEmpty() const {
4428   // Arithmetic or logical right shift does not matter: only testing for 0.
4429   return (fUnion.fFields.fLengthAndFlags>>kLengthShift) == 0;
4430 }
4431 
4432 //========================================
4433 // Write implementation methods
4434 //========================================
4435 inline void
setZeroLength()4436 UnicodeString::setZeroLength() {
4437   fUnion.fFields.fLengthAndFlags &= kAllStorageFlags;
4438 }
4439 
4440 inline void
setShortLength(int32_t len)4441 UnicodeString::setShortLength(int32_t len) {
4442   // requires 0 <= len <= kMaxShortLength
4443   fUnion.fFields.fLengthAndFlags =
4444     (int16_t)((fUnion.fFields.fLengthAndFlags & kAllStorageFlags) | (len << kLengthShift));
4445 }
4446 
4447 inline void
setLength(int32_t len)4448 UnicodeString::setLength(int32_t len) {
4449   if(len <= kMaxShortLength) {
4450     setShortLength(len);
4451   } else {
4452     fUnion.fFields.fLengthAndFlags |= kLengthIsLarge;
4453     fUnion.fFields.fLength = len;
4454   }
4455 }
4456 
4457 inline void
setToEmpty()4458 UnicodeString::setToEmpty() {
4459   fUnion.fFields.fLengthAndFlags = kShortString;
4460 }
4461 
4462 inline void
setArray(UChar * array,int32_t len,int32_t capacity)4463 UnicodeString::setArray(UChar *array, int32_t len, int32_t capacity) {
4464   setLength(len);
4465   fUnion.fFields.fArray = array;
4466   fUnion.fFields.fCapacity = capacity;
4467 }
4468 
4469 inline UnicodeString&
4470 UnicodeString::operator= (UChar ch)
4471 { return doReplace(0, length(), &ch, 0, 1); }
4472 
4473 inline UnicodeString&
4474 UnicodeString::operator= (UChar32 ch)
4475 { return replace(0, length(), ch); }
4476 
4477 inline UnicodeString&
setTo(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4478 UnicodeString::setTo(const UnicodeString& srcText,
4479              int32_t srcStart,
4480              int32_t srcLength)
4481 {
4482   unBogus();
4483   return doReplace(0, length(), srcText, srcStart, srcLength);
4484 }
4485 
4486 inline UnicodeString&
setTo(const UnicodeString & srcText,int32_t srcStart)4487 UnicodeString::setTo(const UnicodeString& srcText,
4488              int32_t srcStart)
4489 {
4490   unBogus();
4491   srcText.pinIndex(srcStart);
4492   return doReplace(0, length(), srcText, srcStart, srcText.length() - srcStart);
4493 }
4494 
4495 inline UnicodeString&
setTo(const UnicodeString & srcText)4496 UnicodeString::setTo(const UnicodeString& srcText)
4497 {
4498   return copyFrom(srcText);
4499 }
4500 
4501 inline UnicodeString&
setTo(const UChar * srcChars,int32_t srcLength)4502 UnicodeString::setTo(const UChar *srcChars,
4503              int32_t srcLength)
4504 {
4505   unBogus();
4506   return doReplace(0, length(), srcChars, 0, srcLength);
4507 }
4508 
4509 inline UnicodeString&
setTo(UChar srcChar)4510 UnicodeString::setTo(UChar srcChar)
4511 {
4512   unBogus();
4513   return doReplace(0, length(), &srcChar, 0, 1);
4514 }
4515 
4516 inline UnicodeString&
setTo(UChar32 srcChar)4517 UnicodeString::setTo(UChar32 srcChar)
4518 {
4519   unBogus();
4520   return replace(0, length(), srcChar);
4521 }
4522 
4523 inline UnicodeString&
append(const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4524 UnicodeString::append(const UnicodeString& srcText,
4525               int32_t srcStart,
4526               int32_t srcLength)
4527 { return doAppend(srcText, srcStart, srcLength); }
4528 
4529 inline UnicodeString&
append(const UnicodeString & srcText)4530 UnicodeString::append(const UnicodeString& srcText)
4531 { return doAppend(srcText, 0, srcText.length()); }
4532 
4533 inline UnicodeString&
append(const UChar * srcChars,int32_t srcStart,int32_t srcLength)4534 UnicodeString::append(const UChar *srcChars,
4535               int32_t srcStart,
4536               int32_t srcLength)
4537 { return doAppend(srcChars, srcStart, srcLength); }
4538 
4539 inline UnicodeString&
append(const UChar * srcChars,int32_t srcLength)4540 UnicodeString::append(const UChar *srcChars,
4541               int32_t srcLength)
4542 { return doAppend(srcChars, 0, srcLength); }
4543 
4544 inline UnicodeString&
append(UChar srcChar)4545 UnicodeString::append(UChar srcChar)
4546 { return doAppend(&srcChar, 0, 1); }
4547 
4548 inline UnicodeString&
4549 UnicodeString::operator+= (UChar ch)
4550 { return doAppend(&ch, 0, 1); }
4551 
4552 inline UnicodeString&
4553 UnicodeString::operator+= (UChar32 ch) {
4554   return append(ch);
4555 }
4556 
4557 inline UnicodeString&
4558 UnicodeString::operator+= (const UnicodeString& srcText)
4559 { return doAppend(srcText, 0, srcText.length()); }
4560 
4561 inline UnicodeString&
insert(int32_t start,const UnicodeString & srcText,int32_t srcStart,int32_t srcLength)4562 UnicodeString::insert(int32_t start,
4563               const UnicodeString& srcText,
4564               int32_t srcStart,
4565               int32_t srcLength)
4566 { return doReplace(start, 0, srcText, srcStart, srcLength); }
4567 
4568 inline UnicodeString&
insert(int32_t start,const UnicodeString & srcText)4569 UnicodeString::insert(int32_t start,
4570               const UnicodeString& srcText)
4571 { return doReplace(start, 0, srcText, 0, srcText.length()); }
4572 
4573 inline UnicodeString&
insert(int32_t start,const UChar * srcChars,int32_t srcStart,int32_t srcLength)4574 UnicodeString::insert(int32_t start,
4575               const UChar *srcChars,
4576               int32_t srcStart,
4577               int32_t srcLength)
4578 { return doReplace(start, 0, srcChars, srcStart, srcLength); }
4579 
4580 inline UnicodeString&
insert(int32_t start,const UChar * srcChars,int32_t srcLength)4581 UnicodeString::insert(int32_t start,
4582               const UChar *srcChars,
4583               int32_t srcLength)
4584 { return doReplace(start, 0, srcChars, 0, srcLength); }
4585 
4586 inline UnicodeString&
insert(int32_t start,UChar srcChar)4587 UnicodeString::insert(int32_t start,
4588               UChar srcChar)
4589 { return doReplace(start, 0, &srcChar, 0, 1); }
4590 
4591 inline UnicodeString&
insert(int32_t start,UChar32 srcChar)4592 UnicodeString::insert(int32_t start,
4593               UChar32 srcChar)
4594 { return replace(start, 0, srcChar); }
4595 
4596 
4597 inline UnicodeString&
remove()4598 UnicodeString::remove()
4599 {
4600   // remove() of a bogus string makes the string empty and non-bogus
4601   if(isBogus()) {
4602     setToEmpty();
4603   } else {
4604     setZeroLength();
4605   }
4606   return *this;
4607 }
4608 
4609 inline UnicodeString&
remove(int32_t start,int32_t _length)4610 UnicodeString::remove(int32_t start,
4611              int32_t _length)
4612 {
4613     if(start <= 0 && _length == INT32_MAX) {
4614         // remove(guaranteed everything) of a bogus string makes the string empty and non-bogus
4615         return remove();
4616     }
4617     return doReplace(start, _length, NULL, 0, 0);
4618 }
4619 
4620 inline UnicodeString&
removeBetween(int32_t start,int32_t limit)4621 UnicodeString::removeBetween(int32_t start,
4622                 int32_t limit)
4623 { return doReplace(start, limit - start, NULL, 0, 0); }
4624 
4625 inline UnicodeString &
retainBetween(int32_t start,int32_t limit)4626 UnicodeString::retainBetween(int32_t start, int32_t limit) {
4627   truncate(limit);
4628   return doReplace(0, start, NULL, 0, 0);
4629 }
4630 
4631 inline UBool
truncate(int32_t targetLength)4632 UnicodeString::truncate(int32_t targetLength)
4633 {
4634   if(isBogus() && targetLength == 0) {
4635     // truncate(0) of a bogus string makes the string empty and non-bogus
4636     unBogus();
4637     return FALSE;
4638   } else if((uint32_t)targetLength < (uint32_t)length()) {
4639     setLength(targetLength);
4640     return TRUE;
4641   } else {
4642     return FALSE;
4643   }
4644 }
4645 
4646 inline UnicodeString&
reverse()4647 UnicodeString::reverse()
4648 { return doReverse(0, length()); }
4649 
4650 inline UnicodeString&
reverse(int32_t start,int32_t _length)4651 UnicodeString::reverse(int32_t start,
4652                int32_t _length)
4653 { return doReverse(start, _length); }
4654 
4655 U_NAMESPACE_END
4656 
4657 #endif
4658