1 /*
2 *****************************************************************************
3 * Copyright (C) 1996-2006, International Business Machines Corporation and others.
4 * All Rights Reserved.
5 *****************************************************************************
6 *
7 * File sortkey.h
8 *
9 * Created by: Helena Shih
10 *
11 * Modification History:
12 *
13 * Date Name Description
14 *
15 * 6/20/97 helena Java class name change.
16 * 8/18/97 helena Added internal API documentation.
17 * 6/26/98 erm Changed to use byte arrays and memcmp.
18 *****************************************************************************
19 */
20
21 #ifndef SORTKEY_H
22 #define SORTKEY_H
23
24 #include "unicode/utypes.h"
25
26 /**
27 * \file
28 * \brief C++ API: Keys for comparing strings multiple times.
29 */
30
31 #if !UCONFIG_NO_COLLATION
32
33 #include "unicode/uobject.h"
34 #include "unicode/unistr.h"
35 #include "unicode/coll.h"
36
37 U_NAMESPACE_BEGIN
38
39 /* forward declaration */
40 class RuleBasedCollator;
41
42 /**
43 *
44 * Collation keys are generated by the Collator class. Use the CollationKey objects
45 * instead of Collator to compare strings multiple times. A CollationKey
46 * preprocesses the comparison information from the Collator object to
47 * make the comparison faster. If you are not going to comparing strings
48 * multiple times, then using the Collator object is generally faster,
49 * since it only processes as much of the string as needed to make a
50 * comparison.
51 * <p> For example (with strength == tertiary)
52 * <p>When comparing "Abernathy" to "Baggins-Smythworthy", Collator
53 * only needs to process a couple of characters, while a comparison
54 * with CollationKeys will process all of the characters. On the other hand,
55 * if you are doing a sort of a number of fields, it is much faster to use
56 * CollationKeys, since you will be comparing strings multiple times.
57 * <p>Typical use of CollationKeys are in databases, where you store a CollationKey
58 * in a hidden field, and use it for sorting or indexing.
59 *
60 * <p>Example of use:
61 * <pre>
62 * \code
63 * UErrorCode success = U_ZERO_ERROR;
64 * Collator* myCollator = Collator::createInstance(success);
65 * CollationKey* keys = new CollationKey [3];
66 * myCollator->getCollationKey("Tom", keys[0], success );
67 * myCollator->getCollationKey("Dick", keys[1], success );
68 * myCollator->getCollationKey("Harry", keys[2], success );
69 *
70 * // Inside body of sort routine, compare keys this way:
71 * CollationKey tmp;
72 * if(keys[0].compareTo( keys[1] ) > 0 ) {
73 * tmp = keys[0]; keys[0] = keys[1]; keys[1] = tmp;
74 * }
75 * //...
76 * \endcode
77 * </pre>
78 * <p>Because Collator::compare()'s algorithm is complex, it is faster to sort
79 * long lists of words by retrieving collation keys with Collator::getCollationKey().
80 * You can then cache the collation keys and compare them using CollationKey::compareTo().
81 * <p>
82 * <strong>Note:</strong> <code>Collator</code>s with different Locale,
83 * CollationStrength and DecompositionMode settings will return different
84 * CollationKeys for the same set of strings. Locales have specific
85 * collation rules, and the way in which secondary and tertiary differences
86 * are taken into account, for example, will result in different CollationKeys
87 * for same strings.
88 * <p>
89
90 * @see Collator
91 * @see RuleBasedCollator
92 * @version 1.3 12/18/96
93 * @author Helena Shih
94 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
95 */
96 class U_I18N_API CollationKey : public UObject {
97 public:
98 /**
99 * This creates an empty collation key based on the null string. An empty
100 * collation key contains no sorting information. When comparing two empty
101 * collation keys, the result is Collator::EQUAL. Comparing empty collation key
102 * with non-empty collation key is always Collator::LESS.
103 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
104 */
105 CollationKey();
106
107
108 /**
109 * Creates a collation key based on the collation key values.
110 * @param values the collation key values
111 * @param count number of collation key values, including trailing nulls.
112 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
113 */
114 CollationKey(const uint8_t* values,
115 int32_t count);
116
117 /**
118 * Copy constructor.
119 * @param other the object to be copied.
120 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
121 */
122 CollationKey(const CollationKey& other);
123
124 /**
125 * Sort key destructor.
126 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
127 */
128 virtual ~CollationKey();
129
130 /**
131 * Assignment operator
132 * @param other the object to be copied.
133 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
134 */
135 const CollationKey& operator=(const CollationKey& other);
136
137 /**
138 * Compare if two collation keys are the same.
139 * @param source the collation key to compare to.
140 * @return Returns true if two collation keys are equal, false otherwise.
141 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
142 */
143 UBool operator==(const CollationKey& source) const;
144
145 /**
146 * Compare if two collation keys are not the same.
147 * @param source the collation key to compare to.
148 * @return Returns TRUE if two collation keys are different, FALSE otherwise.
149 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
150 */
151 UBool operator!=(const CollationKey& source) const;
152
153
154 /**
155 * Test to see if the key is in an invalid state. The key will be in an
156 * invalid state if it couldn't allocate memory for some operation.
157 * @return Returns TRUE if the key is in an invalid, FALSE otherwise.
158 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
159 */
160 UBool isBogus(void) const;
161
162 /**
163 * Returns a pointer to the collation key values. The storage is owned
164 * by the collation key and the pointer will become invalid if the key
165 * is deleted.
166 * @param count the output parameter of number of collation key values,
167 * including any trailing nulls.
168 * @return a pointer to the collation key values.
169 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
170 */
171 const uint8_t* getByteArray(int32_t& count) const;
172
173 #ifdef U_USE_COLLATION_KEY_DEPRECATES
174 /**
175 * Extracts the collation key values into a new array. The caller owns
176 * this storage and should free it.
177 * @param count the output parameter of number of collation key values,
178 * including any trailing nulls.
179 * @obsolete ICU 2.6. Use getByteArray instead since this API will be removed in that release.
180 */
181 uint8_t* toByteArray(int32_t& count) const;
182 #endif
183
184 /**
185 * Convenience method which does a string(bit-wise) comparison of the
186 * two collation keys.
187 * @param target target collation key to be compared with
188 * @return Returns Collator::LESS if sourceKey < targetKey,
189 * Collator::GREATER if sourceKey > targetKey and Collator::EQUAL
190 * otherwise.
191 * @deprecated ICU 2.6 use the overload with error code
192 */
193 Collator::EComparisonResult compareTo(const CollationKey& target) const;
194
195 /**
196 * Convenience method which does a string(bit-wise) comparison of the
197 * two collation keys.
198 * @param target target collation key to be compared with
199 * @param status error code
200 * @return Returns UCOL_LESS if sourceKey < targetKey,
201 * UCOL_GREATER if sourceKey > targetKey and UCOL_EQUAL
202 * otherwise.
203 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
204 */
205 UCollationResult compareTo(const CollationKey& target, UErrorCode &status) const;
206
207 /**
208 * Creates an integer that is unique to the collation key. NOTE: this
209 * is not the same as String.hashCode.
210 * <p>Example of use:
211 * <pre>
212 * . UErrorCode status = U_ZERO_ERROR;
213 * . Collator *myCollation = Collator::createInstance(Locale::US, status);
214 * . if (U_FAILURE(status)) return;
215 * . CollationKey key1, key2;
216 * . UErrorCode status1 = U_ZERO_ERROR, status2 = U_ZERO_ERROR;
217 * . myCollation->getCollationKey("abc", key1, status1);
218 * . if (U_FAILURE(status1)) { delete myCollation; return; }
219 * . myCollation->getCollationKey("ABC", key2, status2);
220 * . if (U_FAILURE(status2)) { delete myCollation; return; }
221 * . // key1.hashCode() != key2.hashCode()
222 * </pre>
223 * @return the hash value based on the string's collation order.
224 * @see UnicodeString#hashCode
225 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
226 */
227 int32_t hashCode(void) const;
228
229 /**
230 * ICU "poor man's RTTI", returns a UClassID for the actual class.
231 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
232 */
233 virtual UClassID getDynamicClassID() const;
234
235 /**
236 * ICU "poor man's RTTI", returns a UClassID for this class.
237 * @deprecated ICU 2.8 Use Collator::getSortKey(...) instead
238 */
239 static UClassID U_EXPORT2 getStaticClassID();
240
241 private:
242 /**
243 * Returns an array of the collation key values as 16-bit integers.
244 * The caller owns the storage and must delete it.
245 * @param values Output param of the collation key values.
246 * @param count output parameter of the number of collation key values
247 * @return a pointer to an array of 16-bit collation key values.
248 */
249 void adopt(uint8_t *values, int32_t count);
250
251 /*
252 * Creates a collation key with a string.
253 */
254
255 /**
256 * If this CollationKey has capacity less than newSize,
257 * its internal capacity will be increased to newSize.
258 * @param newSize minimum size this CollationKey has to have
259 * @return this CollationKey
260 */
261 CollationKey& ensureCapacity(int32_t newSize);
262 /**
263 * Set the CollationKey to a "bogus" or invalid state
264 * @return this CollationKey
265 */
266 CollationKey& setToBogus(void);
267 /**
268 * Resets this CollationKey to an empty state
269 * @return this CollationKey
270 */
271 CollationKey& reset(void);
272
273 /**
274 * Allow private access to RuleBasedCollator
275 */
276 friend class RuleBasedCollator;
277 /**
278 * Bogus status
279 */
280 UBool fBogus;
281 /**
282 * Size of fBytes used to store the sortkey. i.e. up till the
283 * null-termination.
284 */
285 int32_t fCount;
286 /**
287 * Full size of the fBytes
288 */
289 int32_t fCapacity;
290 /**
291 * Unique hash value of this CollationKey
292 */
293 int32_t fHashCode;
294 /**
295 * Array to store the sortkey
296 */
297 uint8_t* fBytes;
298
299 };
300
301 inline UBool
302 CollationKey::operator!=(const CollationKey& other) const
303 {
304 return !(*this == other);
305 }
306
307 inline UBool
isBogus()308 CollationKey::isBogus() const
309 {
310 return fBogus;
311 }
312
313 inline const uint8_t*
getByteArray(int32_t & count)314 CollationKey::getByteArray(int32_t &count) const
315 {
316 count = fCount;
317 return fBytes;
318 }
319
320 U_NAMESPACE_END
321
322 #endif /* #if !UCONFIG_NO_COLLATION */
323
324 #endif
325