1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 *******************************************************************************
5 * Copyright (C) 1996-2012, International Business Machines Corporation and
6 * others. All Rights Reserved.
7 *******************************************************************************
8 */
9 //===============================================================================
10 //
11 // File sortkey.cpp
12 //
13 //
14 //
15 // Created by: Helena Shih
16 //
17 // Modification History:
18 //
19 // Date Name Description
20 //
21 // 6/20/97 helena Java class name change.
22 // 6/23/97 helena Added comments to make code more readable.
23 // 6/26/98 erm Canged to use byte arrays instead of UnicodeString
24 // 7/31/98 erm hashCode: minimum inc should be 2 not 1,
25 // Cleaned up operator=
26 // 07/12/99 helena HPUX 11 CC port.
27 // 03/06/01 synwee Modified compareTo, to handle the result of
28 // 2 string similar in contents, but one is longer
29 // than the other
30 //===============================================================================
31
32 #include "unicode/utypes.h"
33
34 #if !UCONFIG_NO_COLLATION
35
36 #include "unicode/sortkey.h"
37 #include "cmemory.h"
38 #include "uelement.h"
39 #include "ustr_imp.h"
40
41 U_NAMESPACE_BEGIN
42
43 // A hash code of kInvalidHashCode indicates that the hash code needs
44 // to be computed. A hash code of kEmptyHashCode is used for empty keys
45 // and for any key whose computed hash code is kInvalidHashCode.
46 static const int32_t kInvalidHashCode = 0;
47 static const int32_t kEmptyHashCode = 1;
48 // The "bogus hash code" replaces a separate fBogus flag.
49 static const int32_t kBogusHashCode = 2;
50
UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CollationKey)51 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(CollationKey)
52
53 CollationKey::CollationKey()
54 : UObject(), fFlagAndLength(0),
55 fHashCode(kEmptyHashCode)
56 {
57 }
58
59 // Create a collation key from a bit array.
CollationKey(const uint8_t * newValues,int32_t count)60 CollationKey::CollationKey(const uint8_t* newValues, int32_t count)
61 : UObject(), fFlagAndLength(count),
62 fHashCode(kInvalidHashCode)
63 {
64 if (count < 0 || (newValues == NULL && count != 0) ||
65 (count > getCapacity() && reallocate(count, 0) == NULL)) {
66 setToBogus();
67 return;
68 }
69
70 if (count > 0) {
71 uprv_memcpy(getBytes(), newValues, count);
72 }
73 }
74
CollationKey(const CollationKey & other)75 CollationKey::CollationKey(const CollationKey& other)
76 : UObject(other), fFlagAndLength(other.getLength()),
77 fHashCode(other.fHashCode)
78 {
79 if (other.isBogus())
80 {
81 setToBogus();
82 return;
83 }
84
85 int32_t length = fFlagAndLength;
86 if (length > getCapacity() && reallocate(length, 0) == NULL) {
87 setToBogus();
88 return;
89 }
90
91 if (length > 0) {
92 uprv_memcpy(getBytes(), other.getBytes(), length);
93 }
94 }
95
~CollationKey()96 CollationKey::~CollationKey()
97 {
98 if(fFlagAndLength < 0) { uprv_free(fUnion.fFields.fBytes); }
99 }
100
reallocate(int32_t newCapacity,int32_t length)101 uint8_t *CollationKey::reallocate(int32_t newCapacity, int32_t length) {
102 uint8_t *newBytes = static_cast<uint8_t *>(uprv_malloc(newCapacity));
103 if(newBytes == NULL) { return NULL; }
104 if(length > 0) {
105 uprv_memcpy(newBytes, getBytes(), length);
106 }
107 if(fFlagAndLength < 0) { uprv_free(fUnion.fFields.fBytes); }
108 fUnion.fFields.fBytes = newBytes;
109 fUnion.fFields.fCapacity = newCapacity;
110 fFlagAndLength |= 0x80000000;
111 return newBytes;
112 }
113
setLength(int32_t newLength)114 void CollationKey::setLength(int32_t newLength) {
115 // U_ASSERT(newLength >= 0 && newLength <= getCapacity());
116 fFlagAndLength = (fFlagAndLength & 0x80000000) | newLength;
117 fHashCode = kInvalidHashCode;
118 }
119
120 // set the key to an empty state
121 CollationKey&
reset()122 CollationKey::reset()
123 {
124 fFlagAndLength &= 0x80000000;
125 fHashCode = kEmptyHashCode;
126
127 return *this;
128 }
129
130 // set the key to a "bogus" or invalid state
131 CollationKey&
setToBogus()132 CollationKey::setToBogus()
133 {
134 fFlagAndLength &= 0x80000000;
135 fHashCode = kBogusHashCode;
136
137 return *this;
138 }
139
140 UBool
operator ==(const CollationKey & source) const141 CollationKey::operator==(const CollationKey& source) const
142 {
143 return getLength() == source.getLength() &&
144 (this == &source ||
145 uprv_memcmp(getBytes(), source.getBytes(), getLength()) == 0);
146 }
147
148 const CollationKey&
operator =(const CollationKey & other)149 CollationKey::operator=(const CollationKey& other)
150 {
151 if (this != &other)
152 {
153 if (other.isBogus())
154 {
155 return setToBogus();
156 }
157
158 int32_t length = other.getLength();
159 if (length > getCapacity() && reallocate(length, 0) == NULL) {
160 return setToBogus();
161 }
162 if (length > 0) {
163 uprv_memcpy(getBytes(), other.getBytes(), length);
164 }
165 fFlagAndLength = (fFlagAndLength & 0x80000000) | length;
166 fHashCode = other.fHashCode;
167 }
168
169 return *this;
170 }
171
172 // Bitwise comparison for the collation keys.
173 Collator::EComparisonResult
compareTo(const CollationKey & target) const174 CollationKey::compareTo(const CollationKey& target) const
175 {
176 UErrorCode errorCode = U_ZERO_ERROR;
177 return static_cast<Collator::EComparisonResult>(compareTo(target, errorCode));
178 }
179
180 // Bitwise comparison for the collation keys.
181 UCollationResult
compareTo(const CollationKey & target,UErrorCode & status) const182 CollationKey::compareTo(const CollationKey& target, UErrorCode &status) const
183 {
184 if(U_SUCCESS(status)) {
185 const uint8_t *src = getBytes();
186 const uint8_t *tgt = target.getBytes();
187
188 // are we comparing the same string
189 if (src == tgt)
190 return UCOL_EQUAL;
191
192 UCollationResult result;
193
194 // are we comparing different lengths?
195 int32_t minLength = getLength();
196 int32_t targetLength = target.getLength();
197 if (minLength < targetLength) {
198 result = UCOL_LESS;
199 } else if (minLength == targetLength) {
200 result = UCOL_EQUAL;
201 } else {
202 minLength = targetLength;
203 result = UCOL_GREATER;
204 }
205
206 if (minLength > 0) {
207 int diff = uprv_memcmp(src, tgt, minLength);
208 if (diff > 0) {
209 return UCOL_GREATER;
210 }
211 else
212 if (diff < 0) {
213 return UCOL_LESS;
214 }
215 }
216
217 return result;
218 } else {
219 return UCOL_EQUAL;
220 }
221 }
222
223 #ifdef U_USE_COLLATION_KEY_DEPRECATES
224 // Create a copy of the byte array.
225 uint8_t*
toByteArray(int32_t & count) const226 CollationKey::toByteArray(int32_t& count) const
227 {
228 uint8_t *result = (uint8_t*) uprv_malloc( sizeof(uint8_t) * fCount );
229
230 if (result == NULL)
231 {
232 count = 0;
233 }
234 else
235 {
236 count = fCount;
237 if (count > 0) {
238 uprv_memcpy(result, fBytes, fCount);
239 }
240 }
241
242 return result;
243 }
244 #endif
245
246 static int32_t
computeHashCode(const uint8_t * key,int32_t length)247 computeHashCode(const uint8_t *key, int32_t length) {
248 const char *s = reinterpret_cast<const char *>(key);
249 int32_t hash;
250 if (s == NULL || length == 0) {
251 hash = kEmptyHashCode;
252 } else {
253 hash = ustr_hashCharsN(s, length);
254 if (hash == kInvalidHashCode || hash == kBogusHashCode) {
255 hash = kEmptyHashCode;
256 }
257 }
258 return hash;
259 }
260
261 int32_t
hashCode() const262 CollationKey::hashCode() const
263 {
264 // (Cribbed from UnicodeString)
265 // We cache the hashCode; when it becomes invalid, due to any change to the
266 // string, we note this by setting it to kInvalidHashCode. [LIU]
267
268 // Note: This method is semantically const, but physically non-const.
269
270 if (fHashCode == kInvalidHashCode)
271 {
272 fHashCode = computeHashCode(getBytes(), getLength());
273 }
274
275 return fHashCode;
276 }
277
278 U_NAMESPACE_END
279
280 U_CAPI int32_t U_EXPORT2
ucol_keyHashCode(const uint8_t * key,int32_t length)281 ucol_keyHashCode(const uint8_t *key,
282 int32_t length)
283 {
284 return icu::computeHashCode(key, length);
285 }
286
287 #endif /* #if !UCONFIG_NO_COLLATION */
288