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1 /*
2 **********************************************************************
3 *   Copyright (C) 1998-2004, International Business Machines
4 *   Corporation and others.  All Rights Reserved.
5 **********************************************************************
6 *
7 * File ustring.h
8 *
9 * Modification History:
10 *
11 *   Date        Name        Description
12 *   12/07/98    bertrand    Creation.
13 ******************************************************************************
14 */
15 
16 #ifndef USTRING_H
17 #define USTRING_H
18 
19 #include "unicode/utypes.h"
20 #include "unicode/putil.h"
21 #include "unicode/uiter.h"
22 
23 /** Simple declaration for u_strToTitle() to avoid including unicode/ubrk.h. @stable ICU 2.1*/
24 #ifndef UBRK_TYPEDEF_UBREAK_ITERATOR
25 #   define UBRK_TYPEDEF_UBREAK_ITERATOR
26     typedef void UBreakIterator;
27 #endif
28 
29 /**
30  * \file
31  * \brief C API: Unicode string handling functions
32  *
33  * These C API functions provide general Unicode string handling.
34  *
35  * Some functions are equivalent in name, signature, and behavior to the ANSI C <string.h>
36  * functions. (For example, they do not check for bad arguments like NULL string pointers.)
37  * In some cases, only the thread-safe variant of such a function is implemented here
38  * (see u_strtok_r()).
39  *
40  * Other functions provide more Unicode-specific functionality like locale-specific
41  * upper/lower-casing and string comparison in code point order.
42  *
43  * ICU uses 16-bit Unicode (UTF-16) in the form of arrays of UChar code units.
44  * UTF-16 encodes each Unicode code point with either one or two UChar code units.
45  * (This is the default form of Unicode, and a forward-compatible extension of the original,
46  * fixed-width form that was known as UCS-2. UTF-16 superseded UCS-2 with Unicode 2.0
47  * in 1996.)
48  *
49  * Some APIs accept a 32-bit UChar32 value for a single code point.
50  *
51  * ICU also handles 16-bit Unicode text with unpaired surrogates.
52  * Such text is not well-formed UTF-16.
53  * Code-point-related functions treat unpaired surrogates as surrogate code points,
54  * i.e., as separate units.
55  *
56  * Although UTF-16 is a variable-width encoding form (like some legacy multi-byte encodings),
57  * it is much more efficient even for random access because the code unit values
58  * for single-unit characters vs. lead units vs. trail units are completely disjoint.
59  * This means that it is easy to determine character (code point) boundaries from
60  * random offsets in the string.
61  *
62  * Unicode (UTF-16) string processing is optimized for the single-unit case.
63  * Although it is important to support supplementary characters
64  * (which use pairs of lead/trail code units called "surrogates"),
65  * their occurrence is rare. Almost all characters in modern use require only
66  * a single UChar code unit (i.e., their code point values are <=0xffff).
67  *
68  * For more details see the User Guide Strings chapter (http://oss.software.ibm.com/icu/userguide/strings.html).
69  * For a discussion of the handling of unpaired surrogates see also
70  * Jitterbug 2145 and its icu mailing list proposal on 2002-sep-18.
71  */
72 
73 /**
74  * Determine the length of an array of UChar.
75  *
76  * @param s The array of UChars, NULL (U+0000) terminated.
77  * @return The number of UChars in <code>chars</code>, minus the terminator.
78  * @stable ICU 2.0
79  */
80 U_STABLE int32_t U_EXPORT2
81 u_strlen(const UChar *s);
82 
83 /**
84  * Count Unicode code points in the length UChar code units of the string.
85  * A code point may occupy either one or two UChar code units.
86  * Counting code points involves reading all code units.
87  *
88  * This functions is basically the inverse of the U16_FWD_N() macro (see utf.h).
89  *
90  * @param s The input string.
91  * @param length The number of UChar code units to be checked, or -1 to count all
92  *               code points before the first NUL (U+0000).
93  * @return The number of code points in the specified code units.
94  * @stable ICU 2.0
95  */
96 U_STABLE int32_t U_EXPORT2
97 u_countChar32(const UChar *s, int32_t length);
98 
99 /**
100  * Check if the string contains more Unicode code points than a certain number.
101  * This is more efficient than counting all code points in the entire string
102  * and comparing that number with a threshold.
103  * This function may not need to scan the string at all if the length is known
104  * (not -1 for NUL-termination) and falls within a certain range, and
105  * never needs to count more than 'number+1' code points.
106  * Logically equivalent to (u_countChar32(s, length)>number).
107  * A Unicode code point may occupy either one or two UChar code units.
108  *
109  * @param s The input string.
110  * @param length The length of the string, or -1 if it is NUL-terminated.
111  * @param number The number of code points in the string is compared against
112  *               the 'number' parameter.
113  * @return Boolean value for whether the string contains more Unicode code points
114  *         than 'number'. Same as (u_countChar32(s, length)>number).
115  * @stable ICU 2.4
116  */
117 U_STABLE UBool U_EXPORT2
118 u_strHasMoreChar32Than(const UChar *s, int32_t length, int32_t number);
119 
120 /**
121  * Concatenate two ustrings.  Appends a copy of <code>src</code>,
122  * including the null terminator, to <code>dst</code>. The initial copied
123  * character from <code>src</code> overwrites the null terminator in <code>dst</code>.
124  *
125  * @param dst The destination string.
126  * @param src The source string.
127  * @return A pointer to <code>dst</code>.
128  * @stable ICU 2.0
129  */
130 U_STABLE UChar* U_EXPORT2
131 u_strcat(UChar     *dst,
132     const UChar     *src);
133 
134 /**
135  * Concatenate two ustrings.
136  * Appends at most <code>n</code> characters from <code>src</code> to <code>dst</code>.
137  * Adds a terminating NUL.
138  * If src is too long, then only <code>n-1</code> characters will be copied
139  * before the terminating NUL.
140  * If <code>n&lt;=0</code> then dst is not modified.
141  *
142  * @param dst The destination string.
143  * @param src The source string.
144  * @param n The maximum number of characters to compare.
145  * @return A pointer to <code>dst</code>.
146  * @stable ICU 2.0
147  */
148 U_STABLE UChar* U_EXPORT2
149 u_strncat(UChar     *dst,
150      const UChar     *src,
151      int32_t     n);
152 
153 /**
154  * Find the first occurrence of a substring in a string.
155  * The substring is found at code point boundaries.
156  * That means that if the substring begins with
157  * a trail surrogate or ends with a lead surrogate,
158  * then it is found only if these surrogates stand alone in the text.
159  * Otherwise, the substring edge units would be matched against
160  * halves of surrogate pairs.
161  *
162  * @param s The string to search (NUL-terminated).
163  * @param substring The substring to find (NUL-terminated).
164  * @return A pointer to the first occurrence of <code>substring</code> in <code>s</code>,
165  *         or <code>s</code> itself if the <code>substring</code> is empty,
166  *         or <code>NULL</code> if <code>substring</code> is not in <code>s</code>.
167  * @stable ICU 2.0
168  *
169  * @see u_strrstr
170  * @see u_strFindFirst
171  * @see u_strFindLast
172  */
173 U_STABLE UChar * U_EXPORT2
174 u_strstr(const UChar *s, const UChar *substring);
175 
176 /**
177  * Find the first occurrence of a substring in a string.
178  * The substring is found at code point boundaries.
179  * That means that if the substring begins with
180  * a trail surrogate or ends with a lead surrogate,
181  * then it is found only if these surrogates stand alone in the text.
182  * Otherwise, the substring edge units would be matched against
183  * halves of surrogate pairs.
184  *
185  * @param s The string to search.
186  * @param length The length of s (number of UChars), or -1 if it is NUL-terminated.
187  * @param substring The substring to find (NUL-terminated).
188  * @param subLength The length of substring (number of UChars), or -1 if it is NUL-terminated.
189  * @return A pointer to the first occurrence of <code>substring</code> in <code>s</code>,
190  *         or <code>s</code> itself if the <code>substring</code> is empty,
191  *         or <code>NULL</code> if <code>substring</code> is not in <code>s</code>.
192  * @stable ICU 2.4
193  *
194  * @see u_strstr
195  * @see u_strFindLast
196  */
197 U_STABLE UChar * U_EXPORT2
198 u_strFindFirst(const UChar *s, int32_t length, const UChar *substring, int32_t subLength);
199 
200 /**
201  * Find the first occurrence of a BMP code point in a string.
202  * A surrogate code point is found only if its match in the text is not
203  * part of a surrogate pair.
204  * A NUL character is found at the string terminator.
205  *
206  * @param s The string to search (NUL-terminated).
207  * @param c The BMP code point to find.
208  * @return A pointer to the first occurrence of <code>c</code> in <code>s</code>
209  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
210  * @stable ICU 2.0
211  *
212  * @see u_strchr32
213  * @see u_memchr
214  * @see u_strstr
215  * @see u_strFindFirst
216  */
217 U_STABLE UChar * U_EXPORT2
218 u_strchr(const UChar *s, UChar c);
219 
220 /**
221  * Find the first occurrence of a code point in a string.
222  * A surrogate code point is found only if its match in the text is not
223  * part of a surrogate pair.
224  * A NUL character is found at the string terminator.
225  *
226  * @param s The string to search (NUL-terminated).
227  * @param c The code point to find.
228  * @return A pointer to the first occurrence of <code>c</code> in <code>s</code>
229  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
230  * @stable ICU 2.0
231  *
232  * @see u_strchr
233  * @see u_memchr32
234  * @see u_strstr
235  * @see u_strFindFirst
236  */
237 U_STABLE UChar * U_EXPORT2
238 u_strchr32(const UChar *s, UChar32 c);
239 
240 /**
241  * Find the last occurrence of a substring in a string.
242  * The substring is found at code point boundaries.
243  * That means that if the substring begins with
244  * a trail surrogate or ends with a lead surrogate,
245  * then it is found only if these surrogates stand alone in the text.
246  * Otherwise, the substring edge units would be matched against
247  * halves of surrogate pairs.
248  *
249  * @param s The string to search (NUL-terminated).
250  * @param substring The substring to find (NUL-terminated).
251  * @return A pointer to the last occurrence of <code>substring</code> in <code>s</code>,
252  *         or <code>s</code> itself if the <code>substring</code> is empty,
253  *         or <code>NULL</code> if <code>substring</code> is not in <code>s</code>.
254  * @stable ICU 2.4
255  *
256  * @see u_strstr
257  * @see u_strFindFirst
258  * @see u_strFindLast
259  */
260 U_STABLE UChar * U_EXPORT2
261 u_strrstr(const UChar *s, const UChar *substring);
262 
263 /**
264  * Find the last occurrence of a substring in a string.
265  * The substring is found at code point boundaries.
266  * That means that if the substring begins with
267  * a trail surrogate or ends with a lead surrogate,
268  * then it is found only if these surrogates stand alone in the text.
269  * Otherwise, the substring edge units would be matched against
270  * halves of surrogate pairs.
271  *
272  * @param s The string to search.
273  * @param length The length of s (number of UChars), or -1 if it is NUL-terminated.
274  * @param substring The substring to find (NUL-terminated).
275  * @param subLength The length of substring (number of UChars), or -1 if it is NUL-terminated.
276  * @return A pointer to the last occurrence of <code>substring</code> in <code>s</code>,
277  *         or <code>s</code> itself if the <code>substring</code> is empty,
278  *         or <code>NULL</code> if <code>substring</code> is not in <code>s</code>.
279  * @stable ICU 2.4
280  *
281  * @see u_strstr
282  * @see u_strFindLast
283  */
284 U_STABLE UChar * U_EXPORT2
285 u_strFindLast(const UChar *s, int32_t length, const UChar *substring, int32_t subLength);
286 
287 /**
288  * Find the last occurrence of a BMP code point in a string.
289  * A surrogate code point is found only if its match in the text is not
290  * part of a surrogate pair.
291  * A NUL character is found at the string terminator.
292  *
293  * @param s The string to search (NUL-terminated).
294  * @param c The BMP code point to find.
295  * @return A pointer to the last occurrence of <code>c</code> in <code>s</code>
296  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
297  * @stable ICU 2.4
298  *
299  * @see u_strrchr32
300  * @see u_memrchr
301  * @see u_strrstr
302  * @see u_strFindLast
303  */
304 U_STABLE UChar * U_EXPORT2
305 u_strrchr(const UChar *s, UChar c);
306 
307 /**
308  * Find the last occurrence of a code point in a string.
309  * A surrogate code point is found only if its match in the text is not
310  * part of a surrogate pair.
311  * A NUL character is found at the string terminator.
312  *
313  * @param s The string to search (NUL-terminated).
314  * @param c The code point to find.
315  * @return A pointer to the last occurrence of <code>c</code> in <code>s</code>
316  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
317  * @stable ICU 2.4
318  *
319  * @see u_strrchr
320  * @see u_memchr32
321  * @see u_strrstr
322  * @see u_strFindLast
323  */
324 U_STABLE UChar * U_EXPORT2
325 u_strrchr32(const UChar *s, UChar32 c);
326 
327 /**
328  * Locates the first occurrence in the string <code>string</code> of any of the characters
329  * in the string <code>matchSet</code>.
330  * Works just like C's strpbrk but with Unicode.
331  *
332  * @param string The string in which to search, NUL-terminated.
333  * @param matchSet A NUL-terminated string defining a set of code points
334  *                 for which to search in the text string.
335  * @return A pointer to the  character in <code>string</code> that matches one of the
336  *         characters in <code>matchSet</code>, or NULL if no such character is found.
337  * @stable ICU 2.0
338  */
339 U_STABLE UChar * U_EXPORT2
340 u_strpbrk(const UChar *string, const UChar *matchSet);
341 
342 /**
343  * Returns the number of consecutive characters in <code>string</code>,
344  * beginning with the first, that do not occur somewhere in <code>matchSet</code>.
345  * Works just like C's strcspn but with Unicode.
346  *
347  * @param string The string in which to search, NUL-terminated.
348  * @param matchSet A NUL-terminated string defining a set of code points
349  *                 for which to search in the text string.
350  * @return The number of initial characters in <code>string</code> that do not
351  *         occur in <code>matchSet</code>.
352  * @see u_strspn
353  * @stable ICU 2.0
354  */
355 U_STABLE int32_t U_EXPORT2
356 u_strcspn(const UChar *string, const UChar *matchSet);
357 
358 /**
359  * Returns the number of consecutive characters in <code>string</code>,
360  * beginning with the first, that occur somewhere in <code>matchSet</code>.
361  * Works just like C's strspn but with Unicode.
362  *
363  * @param string The string in which to search, NUL-terminated.
364  * @param matchSet A NUL-terminated string defining a set of code points
365  *                 for which to search in the text string.
366  * @return The number of initial characters in <code>string</code> that do
367  *         occur in <code>matchSet</code>.
368  * @see u_strcspn
369  * @stable ICU 2.0
370  */
371 U_STABLE int32_t U_EXPORT2
372 u_strspn(const UChar *string, const UChar *matchSet);
373 
374 /**
375  * The string tokenizer API allows an application to break a string into
376  * tokens. Unlike strtok(), the saveState (the current pointer within the
377  * original string) is maintained in saveState. In the first call, the
378  * argument src is a pointer to the string. In subsequent calls to
379  * return successive tokens of that string, src must be specified as
380  * NULL. The value saveState is set by this function to maintain the
381  * function's position within the string, and on each subsequent call
382  * you must give this argument the same variable. This function does
383  * handle surrogate pairs. This function is similar to the strtok_r()
384  * the POSIX Threads Extension (1003.1c-1995) version.
385  *
386  * @param src String containing token(s). This string will be modified.
387  *            After the first call to u_strtok_r(), this argument must
388  *            be NULL to get to the next token.
389  * @param delim Set of delimiter characters (Unicode code points).
390  * @param saveState The current pointer within the original string,
391  *              which is set by this function. The saveState
392  *              parameter should the address of a local variable of type
393  *              UChar *. (i.e. defined "Uhar *myLocalSaveState" and use
394  *              &myLocalSaveState for this parameter).
395  * @return A pointer to the next token found in src, or NULL
396  *         when there are no more tokens.
397  * @stable ICU 2.0
398  */
399 U_STABLE UChar * U_EXPORT2
400 u_strtok_r(UChar    *src,
401      const UChar    *delim,
402            UChar   **saveState);
403 
404 /**
405  * Compare two Unicode strings for bitwise equality (code unit order).
406  *
407  * @param s1 A string to compare.
408  * @param s2 A string to compare.
409  * @return 0 if <code>s1</code> and <code>s2</code> are bitwise equal; a negative
410  * value if <code>s1</code> is bitwise less than <code>s2,</code>; a positive
411  * value if <code>s1</code> is bitwise greater than <code>s2</code>.
412  * @stable ICU 2.0
413  */
414 U_STABLE int32_t  U_EXPORT2
415 u_strcmp(const UChar     *s1,
416          const UChar     *s2);
417 
418 /**
419  * Compare two Unicode strings in code point order.
420  * See u_strCompare for details.
421  *
422  * @param s1 A string to compare.
423  * @param s2 A string to compare.
424  * @return a negative/zero/positive integer corresponding to whether
425  * the first string is less than/equal to/greater than the second one
426  * in code point order
427  * @stable ICU 2.0
428  */
429 U_STABLE int32_t U_EXPORT2
430 u_strcmpCodePointOrder(const UChar *s1, const UChar *s2);
431 
432 /**
433  * Compare two Unicode strings (binary order).
434  *
435  * The comparison can be done in code unit order or in code point order.
436  * They differ only in UTF-16 when
437  * comparing supplementary code points (U+10000..U+10ffff)
438  * to BMP code points near the end of the BMP (i.e., U+e000..U+ffff).
439  * In code unit order, high BMP code points sort after supplementary code points
440  * because they are stored as pairs of surrogates which are at U+d800..U+dfff.
441  *
442  * This functions works with strings of different explicitly specified lengths
443  * unlike the ANSI C-like u_strcmp() and u_memcmp() etc.
444  * NUL-terminated strings are possible with length arguments of -1.
445  *
446  * @param s1 First source string.
447  * @param length1 Length of first source string, or -1 if NUL-terminated.
448  *
449  * @param s2 Second source string.
450  * @param length2 Length of second source string, or -1 if NUL-terminated.
451  *
452  * @param codePointOrder Choose between code unit order (FALSE)
453  *                       and code point order (TRUE).
454  *
455  * @return <0 or 0 or >0 as usual for string comparisons
456  *
457  * @stable ICU 2.2
458  */
459 U_STABLE int32_t U_EXPORT2
460 u_strCompare(const UChar *s1, int32_t length1,
461              const UChar *s2, int32_t length2,
462              UBool codePointOrder);
463 
464 /**
465  * Compare two Unicode strings (binary order)
466  * as presented by UCharIterator objects.
467  * Works otherwise just like u_strCompare().
468  *
469  * Both iterators are reset to their start positions.
470  * When the function returns, it is undefined where the iterators
471  * have stopped.
472  *
473  * @param iter1 First source string iterator.
474  * @param iter2 Second source string iterator.
475  * @param codePointOrder Choose between code unit order (FALSE)
476  *                       and code point order (TRUE).
477  *
478  * @return <0 or 0 or >0 as usual for string comparisons
479  *
480  * @see u_strCompare
481  *
482  * @stable ICU 2.6
483  */
484 U_STABLE int32_t U_EXPORT2
485 u_strCompareIter(UCharIterator *iter1, UCharIterator *iter2, UBool codePointOrder);
486 
487 #ifndef U_COMPARE_CODE_POINT_ORDER
488 /* see also unistr.h and unorm.h */
489 /**
490  * Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc:
491  * Compare strings in code point order instead of code unit order.
492  * @stable ICU 2.2
493  */
494 #define U_COMPARE_CODE_POINT_ORDER  0x8000
495 #endif
496 
497 /**
498  * Compare two strings case-insensitively using full case folding.
499  * This is equivalent to
500  *   u_strCompare(u_strFoldCase(s1, options),
501  *                u_strFoldCase(s2, options),
502  *                (options&U_COMPARE_CODE_POINT_ORDER)!=0).
503  *
504  * The comparison can be done in UTF-16 code unit order or in code point order.
505  * They differ only when comparing supplementary code points (U+10000..U+10ffff)
506  * to BMP code points near the end of the BMP (i.e., U+e000..U+ffff).
507  * In code unit order, high BMP code points sort after supplementary code points
508  * because they are stored as pairs of surrogates which are at U+d800..U+dfff.
509  *
510  * This functions works with strings of different explicitly specified lengths
511  * unlike the ANSI C-like u_strcmp() and u_memcmp() etc.
512  * NUL-terminated strings are possible with length arguments of -1.
513  *
514  * @param s1 First source string.
515  * @param length1 Length of first source string, or -1 if NUL-terminated.
516  *
517  * @param s2 Second source string.
518  * @param length2 Length of second source string, or -1 if NUL-terminated.
519  *
520  * @param options A bit set of options:
521  *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
522  *     Comparison in code unit order with default case folding.
523  *
524  *   - U_COMPARE_CODE_POINT_ORDER
525  *     Set to choose code point order instead of code unit order
526  *     (see u_strCompare for details).
527  *
528  *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
529  *
530  * @param pErrorCode Must be a valid pointer to an error code value,
531  *                  which must not indicate a failure before the function call.
532  *
533  * @return <0 or 0 or >0 as usual for string comparisons
534  *
535  * @stable ICU 2.2
536  */
537 U_STABLE int32_t U_EXPORT2
538 u_strCaseCompare(const UChar *s1, int32_t length1,
539                  const UChar *s2, int32_t length2,
540                  uint32_t options,
541                  UErrorCode *pErrorCode);
542 
543 /**
544  * Compare two ustrings for bitwise equality.
545  * Compares at most <code>n</code> characters.
546  *
547  * @param ucs1 A string to compare.
548  * @param ucs2 A string to compare.
549  * @param n The maximum number of characters to compare.
550  * @return 0 if <code>s1</code> and <code>s2</code> are bitwise equal; a negative
551  * value if <code>s1</code> is bitwise less than <code>s2</code>; a positive
552  * value if <code>s1</code> is bitwise greater than <code>s2</code>.
553  * @stable ICU 2.0
554  */
555 U_STABLE int32_t U_EXPORT2
556 u_strncmp(const UChar     *ucs1,
557      const UChar     *ucs2,
558      int32_t     n);
559 
560 /**
561  * Compare two Unicode strings in code point order.
562  * This is different in UTF-16 from u_strncmp() if supplementary characters are present.
563  * For details, see u_strCompare().
564  *
565  * @param s1 A string to compare.
566  * @param s2 A string to compare.
567  * @param n The maximum number of characters to compare.
568  * @return a negative/zero/positive integer corresponding to whether
569  * the first string is less than/equal to/greater than the second one
570  * in code point order
571  * @stable ICU 2.0
572  */
573 U_STABLE int32_t U_EXPORT2
574 u_strncmpCodePointOrder(const UChar *s1, const UChar *s2, int32_t n);
575 
576 /**
577  * Compare two strings case-insensitively using full case folding.
578  * This is equivalent to u_strcmp(u_strFoldCase(s1, options), u_strFoldCase(s2, options)).
579  *
580  * @param s1 A string to compare.
581  * @param s2 A string to compare.
582  * @param options A bit set of options:
583  *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
584  *     Comparison in code unit order with default case folding.
585  *
586  *   - U_COMPARE_CODE_POINT_ORDER
587  *     Set to choose code point order instead of code unit order
588  *     (see u_strCompare for details).
589  *
590  *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
591  *
592  * @return A negative, zero, or positive integer indicating the comparison result.
593  * @stable ICU 2.0
594  */
595 U_STABLE int32_t U_EXPORT2
596 u_strcasecmp(const UChar *s1, const UChar *s2, uint32_t options);
597 
598 /**
599  * Compare two strings case-insensitively using full case folding.
600  * This is equivalent to u_strcmp(u_strFoldCase(s1, at most n, options),
601  * u_strFoldCase(s2, at most n, options)).
602  *
603  * @param s1 A string to compare.
604  * @param s2 A string to compare.
605  * @param n The maximum number of characters each string to case-fold and then compare.
606  * @param options A bit set of options:
607  *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
608  *     Comparison in code unit order with default case folding.
609  *
610  *   - U_COMPARE_CODE_POINT_ORDER
611  *     Set to choose code point order instead of code unit order
612  *     (see u_strCompare for details).
613  *
614  *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
615  *
616  * @return A negative, zero, or positive integer indicating the comparison result.
617  * @stable ICU 2.0
618  */
619 U_STABLE int32_t U_EXPORT2
620 u_strncasecmp(const UChar *s1, const UChar *s2, int32_t n, uint32_t options);
621 
622 /**
623  * Compare two strings case-insensitively using full case folding.
624  * This is equivalent to u_strcmp(u_strFoldCase(s1, n, options),
625  * u_strFoldCase(s2, n, options)).
626  *
627  * @param s1 A string to compare.
628  * @param s2 A string to compare.
629  * @param length The number of characters in each string to case-fold and then compare.
630  * @param options A bit set of options:
631  *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
632  *     Comparison in code unit order with default case folding.
633  *
634  *   - U_COMPARE_CODE_POINT_ORDER
635  *     Set to choose code point order instead of code unit order
636  *     (see u_strCompare for details).
637  *
638  *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
639  *
640  * @return A negative, zero, or positive integer indicating the comparison result.
641  * @stable ICU 2.0
642  */
643 U_STABLE int32_t U_EXPORT2
644 u_memcasecmp(const UChar *s1, const UChar *s2, int32_t length, uint32_t options);
645 
646 /**
647  * Copy a ustring. Adds a null terminator.
648  *
649  * @param dst The destination string.
650  * @param src The source string.
651  * @return A pointer to <code>dst</code>.
652  * @stable ICU 2.0
653  */
654 U_STABLE UChar* U_EXPORT2
655 u_strcpy(UChar     *dst,
656     const UChar     *src);
657 
658 /**
659  * Copy a ustring.
660  * Copies at most <code>n</code> characters.  The result will be null terminated
661  * if the length of <code>src</code> is less than <code>n</code>.
662  *
663  * @param dst The destination string.
664  * @param src The source string.
665  * @param n The maximum number of characters to copy.
666  * @return A pointer to <code>dst</code>.
667  * @stable ICU 2.0
668  */
669 U_STABLE UChar* U_EXPORT2
670 u_strncpy(UChar     *dst,
671      const UChar     *src,
672      int32_t     n);
673 
674 #if !UCONFIG_NO_CONVERSION
675 
676 /**
677  * Copy a byte string encoded in the default codepage to a ustring.
678  * Adds a null terminator.
679  * Performs a host byte to UChar conversion
680  *
681  * @param dst The destination string.
682  * @param src The source string.
683  * @return A pointer to <code>dst</code>.
684  * @stable ICU 2.0
685  */
686 U_STABLE UChar* U_EXPORT2 u_uastrcpy(UChar *dst,
687                const char *src );
688 
689 /**
690  * Copy a byte string encoded in the default codepage to a ustring.
691  * Copies at most <code>n</code> characters.  The result will be null terminated
692  * if the length of <code>src</code> is less than <code>n</code>.
693  * Performs a host byte to UChar conversion
694  *
695  * @param dst The destination string.
696  * @param src The source string.
697  * @param n The maximum number of characters to copy.
698  * @return A pointer to <code>dst</code>.
699  * @stable ICU 2.0
700  */
701 U_STABLE UChar* U_EXPORT2 u_uastrncpy(UChar *dst,
702             const char *src,
703             int32_t n);
704 
705 /**
706  * Copy ustring to a byte string encoded in the default codepage.
707  * Adds a null terminator.
708  * Performs a UChar to host byte conversion
709  *
710  * @param dst The destination string.
711  * @param src The source string.
712  * @return A pointer to <code>dst</code>.
713  * @stable ICU 2.0
714  */
715 U_STABLE char* U_EXPORT2 u_austrcpy(char *dst,
716             const UChar *src );
717 
718 /**
719  * Copy ustring to a byte string encoded in the default codepage.
720  * Copies at most <code>n</code> characters.  The result will be null terminated
721  * if the length of <code>src</code> is less than <code>n</code>.
722  * Performs a UChar to host byte conversion
723  *
724  * @param dst The destination string.
725  * @param src The source string.
726  * @param n The maximum number of characters to copy.
727  * @return A pointer to <code>dst</code>.
728  * @stable ICU 2.0
729  */
730 U_STABLE char* U_EXPORT2 u_austrncpy(char *dst,
731             const UChar *src,
732             int32_t n );
733 
734 #endif
735 
736 /**
737  * Synonym for memcpy(), but with UChars only.
738  * @param dest The destination string
739  * @param src The source string
740  * @param count The number of characters to copy
741  * @return A pointer to <code>dest</code>
742  * @stable ICU 2.0
743  */
744 U_STABLE UChar* U_EXPORT2
745 u_memcpy(UChar *dest, const UChar *src, int32_t count);
746 
747 /**
748  * Synonym for memmove(), but with UChars only.
749  * @param dest The destination string
750  * @param src The source string
751  * @param count The number of characters to move
752  * @return A pointer to <code>dest</code>
753  * @stable ICU 2.0
754  */
755 U_STABLE UChar* U_EXPORT2
756 u_memmove(UChar *dest, const UChar *src, int32_t count);
757 
758 /**
759  * Initialize <code>count</code> characters of <code>dest</code> to <code>c</code>.
760  *
761  * @param dest The destination string.
762  * @param c The character to initialize the string.
763  * @param count The maximum number of characters to set.
764  * @return A pointer to <code>dest</code>.
765  * @stable ICU 2.0
766  */
767 U_STABLE UChar* U_EXPORT2
768 u_memset(UChar *dest, UChar c, int32_t count);
769 
770 /**
771  * Compare the first <code>count</code> UChars of each buffer.
772  *
773  * @param buf1 The first string to compare.
774  * @param buf2 The second string to compare.
775  * @param count The maximum number of UChars to compare.
776  * @return When buf1 < buf2, a negative number is returned.
777  *      When buf1 == buf2, 0 is returned.
778  *      When buf1 > buf2, a positive number is returned.
779  * @stable ICU 2.0
780  */
781 U_STABLE int32_t U_EXPORT2
782 u_memcmp(const UChar *buf1, const UChar *buf2, int32_t count);
783 
784 /**
785  * Compare two Unicode strings in code point order.
786  * This is different in UTF-16 from u_memcmp() if supplementary characters are present.
787  * For details, see u_strCompare().
788  *
789  * @param s1 A string to compare.
790  * @param s2 A string to compare.
791  * @param count The maximum number of characters to compare.
792  * @return a negative/zero/positive integer corresponding to whether
793  * the first string is less than/equal to/greater than the second one
794  * in code point order
795  * @stable ICU 2.0
796  */
797 U_STABLE int32_t U_EXPORT2
798 u_memcmpCodePointOrder(const UChar *s1, const UChar *s2, int32_t count);
799 
800 /**
801  * Find the first occurrence of a BMP code point in a string.
802  * A surrogate code point is found only if its match in the text is not
803  * part of a surrogate pair.
804  * A NUL character is found at the string terminator.
805  *
806  * @param s The string to search (contains <code>count</code> UChars).
807  * @param c The BMP code point to find.
808  * @param count The length of the string.
809  * @return A pointer to the first occurrence of <code>c</code> in <code>s</code>
810  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
811  * @stable ICU 2.0
812  *
813  * @see u_strchr
814  * @see u_memchr32
815  * @see u_strFindFirst
816  */
817 U_STABLE UChar* U_EXPORT2
818 u_memchr(const UChar *s, UChar c, int32_t count);
819 
820 /**
821  * Find the first occurrence of a code point in a string.
822  * A surrogate code point is found only if its match in the text is not
823  * part of a surrogate pair.
824  * A NUL character is found at the string terminator.
825  *
826  * @param s The string to search (contains <code>count</code> UChars).
827  * @param c The code point to find.
828  * @param count The length of the string.
829  * @return A pointer to the first occurrence of <code>c</code> in <code>s</code>
830  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
831  * @stable ICU 2.0
832  *
833  * @see u_strchr32
834  * @see u_memchr
835  * @see u_strFindFirst
836  */
837 U_STABLE UChar* U_EXPORT2
838 u_memchr32(const UChar *s, UChar32 c, int32_t count);
839 
840 /**
841  * Find the last occurrence of a BMP code point in a string.
842  * A surrogate code point is found only if its match in the text is not
843  * part of a surrogate pair.
844  * A NUL character is found at the string terminator.
845  *
846  * @param s The string to search (contains <code>count</code> UChars).
847  * @param c The BMP code point to find.
848  * @param count The length of the string.
849  * @return A pointer to the last occurrence of <code>c</code> in <code>s</code>
850  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
851  * @stable ICU 2.4
852  *
853  * @see u_strrchr
854  * @see u_memrchr32
855  * @see u_strFindLast
856  */
857 U_STABLE UChar* U_EXPORT2
858 u_memrchr(const UChar *s, UChar c, int32_t count);
859 
860 /**
861  * Find the last occurrence of a code point in a string.
862  * A surrogate code point is found only if its match in the text is not
863  * part of a surrogate pair.
864  * A NUL character is found at the string terminator.
865  *
866  * @param s The string to search (contains <code>count</code> UChars).
867  * @param c The code point to find.
868  * @param count The length of the string.
869  * @return A pointer to the last occurrence of <code>c</code> in <code>s</code>
870  *         or <code>NULL</code> if <code>c</code> is not in <code>s</code>.
871  * @stable ICU 2.4
872  *
873  * @see u_strrchr32
874  * @see u_memrchr
875  * @see u_strFindLast
876  */
877 U_STABLE UChar* U_EXPORT2
878 u_memrchr32(const UChar *s, UChar32 c, int32_t count);
879 
880 /**
881  * Unicode String literals in C.
882  * We need one macro to declare a variable for the string
883  * and to statically preinitialize it if possible,
884  * and a second macro to dynamically intialize such a string variable if necessary.
885  *
886  * The macros are defined for maximum performance.
887  * They work only for strings that contain "invariant characters", i.e.,
888  * only latin letters, digits, and some punctuation.
889  * See utypes.h for details.
890  *
891  * A pair of macros for a single string must be used with the same
892  * parameters.
893  * The string parameter must be a C string literal.
894  * The length of the string, not including the terminating
895  * <code>NUL</code>, must be specified as a constant.
896  * The U_STRING_DECL macro should be invoked exactly once for one
897  * such string variable before it is used.
898  *
899  * Usage:
900  * <pre>
901  * &#32;   U_STRING_DECL(ustringVar1, "Quick-Fox 2", 11);
902  * &#32;   U_STRING_DECL(ustringVar2, "jumps 5%", 8);
903  * &#32;   static UBool didInit=FALSE;
904  * &#32;
905  * &#32;   int32_t function() {
906  * &#32;       if(!didInit) {
907  * &#32;           U_STRING_INIT(ustringVar1, "Quick-Fox 2", 11);
908  * &#32;           U_STRING_INIT(ustringVar2, "jumps 5%", 8);
909  * &#32;           didInit=TRUE;
910  * &#32;       }
911  * &#32;       return u_strcmp(ustringVar1, ustringVar2);
912  * &#32;   }
913  * </pre>
914  * @stable ICU 2.0
915  */
916 #if U_SIZEOF_WCHAR_T==U_SIZEOF_UCHAR && U_CHARSET_FAMILY==U_ASCII_FAMILY
917 #   define U_STRING_DECL(var, cs, length) static const wchar_t var[(length)+1]={ L ## cs }
918     /**@stable ICU 2.0 */
919 #   define U_STRING_INIT(var, cs, length)
920 #elif U_SIZEOF_UCHAR==1 && U_CHARSET_FAMILY==U_ASCII_FAMILY
921 #   define U_STRING_DECL(var, cs, length) static const UChar var[(length)+1]={ (const UChar *)cs }
922     /**@stable ICU 2.0 */
923 #   define U_STRING_INIT(var, cs, length)
924 #else
925 #   define U_STRING_DECL(var, cs, length) static UChar var[(length)+1]
926     /**@stable ICU 2.0 */
927 #   define U_STRING_INIT(var, cs, length) u_charsToUChars(cs, var, length+1)
928 #endif
929 
930 /**
931  * Unescape a string of characters and write the resulting
932  * Unicode characters to the destination buffer.  The following escape
933  * sequences are recognized:
934  *
935  * \\uhhhh       4 hex digits; h in [0-9A-Fa-f]
936  * \\Uhhhhhhhh   8 hex digits
937  * \\xhh         1-2 hex digits
938  * \\x{h...}     1-8 hex digits
939  * \\ooo         1-3 octal digits; o in [0-7]
940  * \\cX          control-X; X is masked with 0x1F
941  *
942  * as well as the standard ANSI C escapes:
943  *
944  * \\a => U+0007, \\b => U+0008, \\t => U+0009, \\n => U+000A,
945  * \\v => U+000B, \\f => U+000C, \\r => U+000D, \\e => U+001B,
946  * \\" => U+0022, \\' => U+0027, \\? => U+003F, \\\\ => U+005C
947  *
948  * Anything else following a backslash is generically escaped.  For
949  * example, "[a\\-z]" returns "[a-z]".
950  *
951  * If an escape sequence is ill-formed, this method returns an empty
952  * string.  An example of an ill-formed sequence is "\\u" followed by
953  * fewer than 4 hex digits.
954  *
955  * The above characters are recognized in the compiler's codepage,
956  * that is, they are coded as 'u', '\\', etc.  Characters that are
957  * not parts of escape sequences are converted using u_charsToUChars().
958  *
959  * This function is similar to UnicodeString::unescape() but not
960  * identical to it.  The latter takes a source UnicodeString, so it
961  * does escape recognition but no conversion.
962  *
963  * @param src a zero-terminated string of invariant characters
964  * @param dest pointer to buffer to receive converted and unescaped
965  * text and, if there is room, a zero terminator.  May be NULL for
966  * preflighting, in which case no UChars will be written, but the
967  * return value will still be valid.  On error, an empty string is
968  * stored here (if possible).
969  * @param destCapacity the number of UChars that may be written at
970  * dest.  Ignored if dest == NULL.
971  * @return the length of unescaped string.
972  * @see u_unescapeAt
973  * @see UnicodeString#unescape()
974  * @see UnicodeString#unescapeAt()
975  * @stable ICU 2.0
976  */
977 U_STABLE int32_t U_EXPORT2
978 u_unescape(const char *src,
979            UChar *dest, int32_t destCapacity);
980 
981 U_CDECL_BEGIN
982 /**
983  * Callback function for u_unescapeAt() that returns a character of
984  * the source text given an offset and a context pointer.  The context
985  * pointer will be whatever is passed into u_unescapeAt().
986  *
987  * @param offset pointer to the offset that will be passed to u_unescapeAt().
988  * @param context an opaque pointer passed directly into u_unescapeAt()
989  * @return the character represented by the escape sequence at
990  * offset
991  * @see u_unescapeAt
992  * @stable ICU 2.0
993  */
994 typedef UChar (U_CALLCONV *UNESCAPE_CHAR_AT)(int32_t offset, void *context);
995 U_CDECL_END
996 
997 /**
998  * Unescape a single sequence. The character at offset-1 is assumed
999  * (without checking) to be a backslash.  This method takes a callback
1000  * pointer to a function that returns the UChar at a given offset.  By
1001  * varying this callback, ICU functions are able to unescape char*
1002  * strings, UnicodeString objects, and UFILE pointers.
1003  *
1004  * If offset is out of range, or if the escape sequence is ill-formed,
1005  * (UChar32)0xFFFFFFFF is returned.  See documentation of u_unescape()
1006  * for a list of recognized sequences.
1007  *
1008  * @param charAt callback function that returns a UChar of the source
1009  * text given an offset and a context pointer.
1010  * @param offset pointer to the offset that will be passed to charAt.
1011  * The offset value will be updated upon return to point after the
1012  * last parsed character of the escape sequence.  On error the offset
1013  * is unchanged.
1014  * @param length the number of characters in the source text.  The
1015  * last character of the source text is considered to be at offset
1016  * length-1.
1017  * @param context an opaque pointer passed directly into charAt.
1018  * @return the character represented by the escape sequence at
1019  * offset, or (UChar32)0xFFFFFFFF on error.
1020  * @see u_unescape()
1021  * @see UnicodeString#unescape()
1022  * @see UnicodeString#unescapeAt()
1023  * @stable ICU 2.0
1024  */
1025 U_STABLE UChar32 U_EXPORT2
1026 u_unescapeAt(UNESCAPE_CHAR_AT charAt,
1027              int32_t *offset,
1028              int32_t length,
1029              void *context);
1030 
1031 /**
1032  * Uppercase the characters in a string.
1033  * Casing is locale-dependent and context-sensitive.
1034  * The result may be longer or shorter than the original.
1035  * The source string and the destination buffer are allowed to overlap.
1036  *
1037  * @param dest      A buffer for the result string. The result will be zero-terminated if
1038  *                  the buffer is large enough.
1039  * @param destCapacity The size of the buffer (number of UChars). If it is 0, then
1040  *                  dest may be NULL and the function will only return the length of the result
1041  *                  without writing any of the result string.
1042  * @param src       The original string
1043  * @param srcLength The length of the original string. If -1, then src must be zero-terminated.
1044  * @param locale    The locale to consider, or "" for the root locale or NULL for the default locale.
1045  * @param pErrorCode Must be a valid pointer to an error code value,
1046  *                  which must not indicate a failure before the function call.
1047  * @return The length of the result string. It may be greater than destCapacity. In that case,
1048  *         only some of the result was written to the destination buffer.
1049  * @stable ICU 2.0
1050  */
1051 U_STABLE int32_t U_EXPORT2
1052 u_strToUpper(UChar *dest, int32_t destCapacity,
1053              const UChar *src, int32_t srcLength,
1054              const char *locale,
1055              UErrorCode *pErrorCode);
1056 
1057 /**
1058  * Lowercase the characters in a string.
1059  * Casing is locale-dependent and context-sensitive.
1060  * The result may be longer or shorter than the original.
1061  * The source string and the destination buffer are allowed to overlap.
1062  *
1063  * @param dest      A buffer for the result string. The result will be zero-terminated if
1064  *                  the buffer is large enough.
1065  * @param destCapacity The size of the buffer (number of UChars). If it is 0, then
1066  *                  dest may be NULL and the function will only return the length of the result
1067  *                  without writing any of the result string.
1068  * @param src       The original string
1069  * @param srcLength The length of the original string. If -1, then src must be zero-terminated.
1070  * @param locale    The locale to consider, or "" for the root locale or NULL for the default locale.
1071  * @param pErrorCode Must be a valid pointer to an error code value,
1072  *                  which must not indicate a failure before the function call.
1073  * @return The length of the result string. It may be greater than destCapacity. In that case,
1074  *         only some of the result was written to the destination buffer.
1075  * @stable ICU 2.0
1076  */
1077 U_STABLE int32_t U_EXPORT2
1078 u_strToLower(UChar *dest, int32_t destCapacity,
1079              const UChar *src, int32_t srcLength,
1080              const char *locale,
1081              UErrorCode *pErrorCode);
1082 
1083 #if !UCONFIG_NO_BREAK_ITERATION
1084 
1085 /**
1086  * Titlecase a string.
1087  * Casing is locale-dependent and context-sensitive.
1088  * Titlecasing uses a break iterator to find the first characters of words
1089  * that are to be titlecased. It titlecases those characters and lowercases
1090  * all others.
1091  *
1092  * The titlecase break iterator can be provided to customize for arbitrary
1093  * styles, using rules and dictionaries beyond the standard iterators.
1094  * It may be more efficient to always provide an iterator to avoid
1095  * opening and closing one for each string.
1096  * The standard titlecase iterator for the root locale implements the
1097  * algorithm of Unicode TR 21.
1098  *
1099  * This function uses only the first() and next() methods of the
1100  * provided break iterator.
1101  *
1102  * The result may be longer or shorter than the original.
1103  * The source string and the destination buffer are allowed to overlap.
1104  *
1105  * @param dest      A buffer for the result string. The result will be zero-terminated if
1106  *                  the buffer is large enough.
1107  * @param destCapacity The size of the buffer (number of UChars). If it is 0, then
1108  *                  dest may be NULL and the function will only return the length of the result
1109  *                  without writing any of the result string.
1110  * @param src       The original string
1111  * @param srcLength The length of the original string. If -1, then src must be zero-terminated.
1112  * @param titleIter A break iterator to find the first characters of words
1113  *                  that are to be titlecased.
1114  *                  If none is provided (NULL), then a standard titlecase
1115  *                  break iterator is opened.
1116  * @param locale    The locale to consider, or "" for the root locale or NULL for the default locale.
1117  * @param pErrorCode Must be a valid pointer to an error code value,
1118  *                  which must not indicate a failure before the function call.
1119  * @return The length of the result string. It may be greater than destCapacity. In that case,
1120  *         only some of the result was written to the destination buffer.
1121  * @stable ICU 2.1
1122  */
1123 U_STABLE int32_t U_EXPORT2
1124 u_strToTitle(UChar *dest, int32_t destCapacity,
1125              const UChar *src, int32_t srcLength,
1126              UBreakIterator *titleIter,
1127              const char *locale,
1128              UErrorCode *pErrorCode);
1129 
1130 #endif
1131 
1132 /**
1133  * Case-fold the characters in a string.
1134  * Case-folding is locale-independent and not context-sensitive,
1135  * but there is an option for whether to include or exclude mappings for dotted I
1136  * and dotless i that are marked with 'I' in CaseFolding.txt.
1137  * The result may be longer or shorter than the original.
1138  * The source string and the destination buffer are allowed to overlap.
1139  *
1140  * @param dest      A buffer for the result string. The result will be zero-terminated if
1141  *                  the buffer is large enough.
1142  * @param destCapacity The size of the buffer (number of UChars). If it is 0, then
1143  *                  dest may be NULL and the function will only return the length of the result
1144  *                  without writing any of the result string.
1145  * @param src       The original string
1146  * @param srcLength The length of the original string. If -1, then src must be zero-terminated.
1147  * @param options   Either U_FOLD_CASE_DEFAULT or U_FOLD_CASE_EXCLUDE_SPECIAL_I
1148  * @param pErrorCode Must be a valid pointer to an error code value,
1149  *                  which must not indicate a failure before the function call.
1150  * @return The length of the result string. It may be greater than destCapacity. In that case,
1151  *         only some of the result was written to the destination buffer.
1152  * @stable ICU 2.0
1153  */
1154 U_STABLE int32_t U_EXPORT2
1155 u_strFoldCase(UChar *dest, int32_t destCapacity,
1156               const UChar *src, int32_t srcLength,
1157               uint32_t options,
1158               UErrorCode *pErrorCode);
1159 
1160 /**
1161  * Converts a sequence of UChars to wchar_t units.
1162  *
1163  * @param dest          A buffer for the result string. The result will be zero-terminated if
1164  *                      the buffer is large enough.
1165  * @param destCapacity  The size of the buffer (number of wchar_t's). If it is 0, then
1166  *                      dest may be NULL and the function will only return the length of the
1167  *                      result without writing any of the result string (pre-flighting).
1168  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1169  *                      pDestLength!=NULL then *pDestLength is always set to the
1170  *                      number of output units corresponding to the transformation of
1171  *                      all the input units, even in case of a buffer overflow.
1172  * @param src           The original source string
1173  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1174  * @param pErrorCode    Must be a valid pointer to an error code value,
1175  *                      which must not indicate a failure before the function call.
1176  * @return The pointer to destination buffer.
1177  * @stable ICU 2.0
1178  */
1179 U_STABLE wchar_t* U_EXPORT2
1180 u_strToWCS(wchar_t *dest,
1181            int32_t destCapacity,
1182            int32_t *pDestLength,
1183            const UChar *src,
1184            int32_t srcLength,
1185            UErrorCode *pErrorCode);
1186 /**
1187  * Converts a sequence of wchar_t units to UChars
1188  *
1189  * @param dest          A buffer for the result string. The result will be zero-terminated if
1190  *                      the buffer is large enough.
1191  * @param destCapacity  The size of the buffer (number of UChars). If it is 0, then
1192  *                      dest may be NULL and the function will only return the length of the
1193  *                      result without writing any of the result string (pre-flighting).
1194  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1195  *                      pDestLength!=NULL then *pDestLength is always set to the
1196  *                      number of output units corresponding to the transformation of
1197  *                      all the input units, even in case of a buffer overflow.
1198  * @param src           The original source string
1199  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1200  * @param pErrorCode    Must be a valid pointer to an error code value,
1201  *                      which must not indicate a failure before the function call.
1202  * @return The pointer to destination buffer.
1203  * @stable ICU 2.0
1204  */
1205 U_STABLE UChar* U_EXPORT2
1206 u_strFromWCS(UChar   *dest,
1207              int32_t destCapacity,
1208              int32_t *pDestLength,
1209              const wchar_t *src,
1210              int32_t srcLength,
1211              UErrorCode *pErrorCode);
1212 /**
1213  * Converts a sequence of UChars (UTF-16) to UTF-8 bytes
1214  *
1215  * @param dest          A buffer for the result string. The result will be zero-terminated if
1216  *                      the buffer is large enough.
1217  * @param destCapacity  The size of the buffer (number of chars). If it is 0, then
1218  *                      dest may be NULL and the function will only return the length of the
1219  *                      result without writing any of the result string (pre-flighting).
1220  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1221  *                      pDestLength!=NULL then *pDestLength is always set to the
1222  *                      number of output units corresponding to the transformation of
1223  *                      all the input units, even in case of a buffer overflow.
1224  * @param src           The original source string
1225  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1226  * @param pErrorCode    Must be a valid pointer to an error code value,
1227  *                      which must not indicate a failure before the function call.
1228  * @return The pointer to destination buffer.
1229  * @stable ICU 2.0
1230  */
1231 U_STABLE char* U_EXPORT2
1232 u_strToUTF8(char *dest,
1233             int32_t destCapacity,
1234             int32_t *pDestLength,
1235             const UChar *src,
1236             int32_t srcLength,
1237             UErrorCode *pErrorCode);
1238 
1239 /**
1240  * Converts a sequence of UTF-8 bytes to UChars (UTF-16).
1241  *
1242  * @param dest          A buffer for the result string. The result will be zero-terminated if
1243  *                      the buffer is large enough.
1244  * @param destCapacity  The size of the buffer (number of UChars). If it is 0, then
1245  *                      dest may be NULL and the function will only return the length of the
1246  *                      result without writing any of the result string (pre-flighting).
1247  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1248  *                      pDestLength!=NULL then *pDestLength is always set to the
1249  *                      number of output units corresponding to the transformation of
1250  *                      all the input units, even in case of a buffer overflow.
1251  * @param src           The original source string
1252  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1253  * @param pErrorCode    Must be a valid pointer to an error code value,
1254  *                      which must not indicate a failure before the function call.
1255  * @return The pointer to destination buffer.
1256  * @stable ICU 2.0
1257  */
1258 U_STABLE UChar* U_EXPORT2
1259 u_strFromUTF8(UChar *dest,
1260               int32_t destCapacity,
1261               int32_t *pDestLength,
1262               const char *src,
1263               int32_t srcLength,
1264               UErrorCode *pErrorCode);
1265 
1266 /**
1267  * Converts a sequence of UChars (UTF-16) to UTF32 units.
1268  *
1269  * @param dest          A buffer for the result string. The result will be zero-terminated if
1270  *                      the buffer is large enough.
1271  * @param destCapacity  The size of the buffer (number of UChar32s). If it is 0, then
1272  *                      dest may be NULL and the function will only return the length of the
1273  *                      result without writing any of the result string (pre-flighting).
1274  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1275  *                      pDestLength!=NULL then *pDestLength is always set to the
1276  *                      number of output units corresponding to the transformation of
1277  *                      all the input units, even in case of a buffer overflow.
1278  * @param src           The original source string
1279  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1280  * @param pErrorCode    Must be a valid pointer to an error code value,
1281  *                      which must not indicate a failure before the function call.
1282  * @return The pointer to destination buffer.
1283  * @stable ICU 2.0
1284  */
1285 U_STABLE UChar32* U_EXPORT2
1286 u_strToUTF32(UChar32 *dest,
1287              int32_t  destCapacity,
1288              int32_t  *pDestLength,
1289              const UChar *src,
1290              int32_t  srcLength,
1291              UErrorCode *pErrorCode);
1292 
1293 /**
1294  * Converts a sequence of UTF32 units to UChars (UTF-16)
1295  *
1296  * @param dest          A buffer for the result string. The result will be zero-terminated if
1297  *                      the buffer is large enough.
1298  * @param destCapacity  The size of the buffer (number of UChars). If it is 0, then
1299  *                      dest may be NULL and the function will only return the length of the
1300  *                      result without writing any of the result string (pre-flighting).
1301  * @param pDestLength   A pointer to receive the number of units written to the destination. If
1302  *                      pDestLength!=NULL then *pDestLength is always set to the
1303  *                      number of output units corresponding to the transformation of
1304  *                      all the input units, even in case of a buffer overflow.
1305  * @param src           The original source string
1306  * @param srcLength     The length of the original string. If -1, then src must be zero-terminated.
1307  * @param pErrorCode    Must be a valid pointer to an error code value,
1308  *                      which must not indicate a failure before the function call.
1309  * @return The pointer to destination buffer.
1310  * @stable ICU 2.0
1311  */
1312 U_STABLE UChar* U_EXPORT2
1313 u_strFromUTF32(UChar   *dest,
1314                int32_t destCapacity,
1315                int32_t *pDestLength,
1316                const UChar32 *src,
1317                int32_t srcLength,
1318                UErrorCode *pErrorCode);
1319 
1320 #endif
1321