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1 /* | |
2 ** 2007 June 22 | |
3 ** | |
4 ** The author disclaims copyright to this source code. In place of | |
5 ** a legal notice, here is a blessing: | |
6 ** | |
7 ** May you do good and not evil. | |
8 ** May you find forgiveness for yourself and forgive others. | |
9 ** May you share freely, never taking more than you give. | |
10 ** | |
11 ************************************************************************* | |
12 ** This file implements a tokenizer for fts3 based on the ICU library. | |
13 */ | |
14 #include "fts3Int.h" | |
15 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) | |
16 #ifdef SQLITE_ENABLE_ICU | |
17 | |
18 #include <assert.h> | |
19 #include <string.h> | |
20 #include "fts3_tokenizer.h" | |
21 | |
22 #include <unicode/ubrk.h> | |
23 #include <unicode/ucol.h> | |
24 #include <unicode/ustring.h> | |
25 #include <unicode/utf16.h> | |
26 | |
27 typedef struct IcuTokenizer IcuTokenizer; | |
28 typedef struct IcuCursor IcuCursor; | |
29 | |
30 struct IcuTokenizer { | |
31 sqlite3_tokenizer base; | |
32 char *zLocale; | |
33 }; | |
34 | |
35 struct IcuCursor { | |
36 sqlite3_tokenizer_cursor base; | |
37 | |
38 UBreakIterator *pIter; /* ICU break-iterator object */ | |
39 int nChar; /* Number of UChar elements in pInput */ | |
40 UChar *aChar; /* Copy of input using utf-16 encoding */ | |
41 int *aOffset; /* Offsets of each character in utf-8 input */ | |
42 | |
43 int nBuffer; | |
44 char *zBuffer; | |
45 | |
46 int iToken; | |
47 }; | |
48 | |
49 /* | |
50 ** Create a new tokenizer instance. | |
51 */ | |
52 static int icuCreate( | |
53 int argc, /* Number of entries in argv[] */ | |
54 const char * const *argv, /* Tokenizer creation arguments */ | |
55 sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */ | |
56 ){ | |
57 IcuTokenizer *p; | |
58 int n = 0; | |
59 | |
60 if( argc>0 ){ | |
61 n = strlen(argv[0])+1; | |
62 } | |
63 p = (IcuTokenizer *)sqlite3_malloc(sizeof(IcuTokenizer)+n); | |
64 if( !p ){ | |
65 return SQLITE_NOMEM; | |
66 } | |
67 memset(p, 0, sizeof(IcuTokenizer)); | |
68 | |
69 if( n ){ | |
70 p->zLocale = (char *)&p[1]; | |
71 memcpy(p->zLocale, argv[0], n); | |
72 } | |
73 | |
74 *ppTokenizer = (sqlite3_tokenizer *)p; | |
75 | |
76 return SQLITE_OK; | |
77 } | |
78 | |
79 /* | |
80 ** Destroy a tokenizer | |
81 */ | |
82 static int icuDestroy(sqlite3_tokenizer *pTokenizer){ | |
83 IcuTokenizer *p = (IcuTokenizer *)pTokenizer; | |
84 sqlite3_free(p); | |
85 return SQLITE_OK; | |
86 } | |
87 | |
88 /* | |
89 ** Prepare to begin tokenizing a particular string. The input | |
90 ** string to be tokenized is pInput[0..nBytes-1]. A cursor | |
91 ** used to incrementally tokenize this string is returned in | |
92 ** *ppCursor. | |
93 */ | |
94 static int icuOpen( | |
95 sqlite3_tokenizer *pTokenizer, /* The tokenizer */ | |
96 const char *zInput, /* Input string */ | |
97 int nInput, /* Length of zInput in bytes */ | |
98 sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */ | |
99 ){ | |
100 IcuTokenizer *p = (IcuTokenizer *)pTokenizer; | |
101 IcuCursor *pCsr; | |
102 | |
103 const int32_t opt = U_FOLD_CASE_DEFAULT; | |
104 UErrorCode status = U_ZERO_ERROR; | |
105 int nChar; | |
106 | |
107 UChar32 c; | |
108 int iInput = 0; | |
109 int iOut = 0; | |
110 | |
111 *ppCursor = 0; | |
112 | |
113 if( zInput==0 ){ | |
114 nInput = 0; | |
115 zInput = ""; | |
116 }else if( nInput<0 ){ | |
117 nInput = strlen(zInput); | |
118 } | |
119 nChar = nInput+1; | |
120 pCsr = (IcuCursor *)sqlite3_malloc( | |
121 sizeof(IcuCursor) + /* IcuCursor */ | |
122 ((nChar+3)&~3) * sizeof(UChar) + /* IcuCursor.aChar[] */ | |
123 (nChar+1) * sizeof(int) /* IcuCursor.aOffset[] */ | |
124 ); | |
125 if( !pCsr ){ | |
126 return SQLITE_NOMEM; | |
127 } | |
128 memset(pCsr, 0, sizeof(IcuCursor)); | |
129 pCsr->aChar = (UChar *)&pCsr[1]; | |
130 pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3]; | |
131 | |
132 pCsr->aOffset[iOut] = iInput; | |
133 U8_NEXT(zInput, iInput, nInput, c); | |
134 while( c>0 ){ | |
135 int isError = 0; | |
136 c = u_foldCase(c, opt); | |
137 U16_APPEND(pCsr->aChar, iOut, nChar, c, isError); | |
138 if( isError ){ | |
139 sqlite3_free(pCsr); | |
140 return SQLITE_ERROR; | |
141 } | |
142 pCsr->aOffset[iOut] = iInput; | |
143 | |
144 if( iInput<nInput ){ | |
145 U8_NEXT(zInput, iInput, nInput, c); | |
146 }else{ | |
147 c = 0; | |
148 } | |
149 } | |
150 | |
151 pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status); | |
152 if( !U_SUCCESS(status) ){ | |
153 sqlite3_free(pCsr); | |
154 return SQLITE_ERROR; | |
155 } | |
156 pCsr->nChar = iOut; | |
157 | |
158 ubrk_first(pCsr->pIter); | |
159 *ppCursor = (sqlite3_tokenizer_cursor *)pCsr; | |
160 return SQLITE_OK; | |
161 } | |
162 | |
163 /* | |
164 ** Close a tokenization cursor previously opened by a call to icuOpen(). | |
165 */ | |
166 static int icuClose(sqlite3_tokenizer_cursor *pCursor){ | |
167 IcuCursor *pCsr = (IcuCursor *)pCursor; | |
168 ubrk_close(pCsr->pIter); | |
169 sqlite3_free(pCsr->zBuffer); | |
170 sqlite3_free(pCsr); | |
171 return SQLITE_OK; | |
172 } | |
173 | |
174 /* | |
175 ** Extract the next token from a tokenization cursor. | |
176 */ | |
177 static int icuNext( | |
178 sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */ | |
179 const char **ppToken, /* OUT: *ppToken is the token text */ | |
180 int *pnBytes, /* OUT: Number of bytes in token */ | |
181 int *piStartOffset, /* OUT: Starting offset of token */ | |
182 int *piEndOffset, /* OUT: Ending offset of token */ | |
183 int *piPosition /* OUT: Position integer of token */ | |
184 ){ | |
185 IcuCursor *pCsr = (IcuCursor *)pCursor; | |
186 | |
187 int iStart = 0; | |
188 int iEnd = 0; | |
189 int nByte = 0; | |
190 | |
191 while( iStart==iEnd ){ | |
192 UChar32 c; | |
193 | |
194 iStart = ubrk_current(pCsr->pIter); | |
195 iEnd = ubrk_next(pCsr->pIter); | |
196 if( iEnd==UBRK_DONE ){ | |
197 return SQLITE_DONE; | |
198 } | |
199 | |
200 while( iStart<iEnd ){ | |
201 int iWhite = iStart; | |
202 U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c); | |
203 if( u_isspace(c) ){ | |
204 iStart = iWhite; | |
205 }else{ | |
206 break; | |
207 } | |
208 } | |
209 assert(iStart<=iEnd); | |
210 } | |
211 | |
212 do { | |
213 UErrorCode status = U_ZERO_ERROR; | |
214 if( nByte ){ | |
215 char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte); | |
216 if( !zNew ){ | |
217 return SQLITE_NOMEM; | |
218 } | |
219 pCsr->zBuffer = zNew; | |
220 pCsr->nBuffer = nByte; | |
221 } | |
222 | |
223 u_strToUTF8( | |
224 pCsr->zBuffer, pCsr->nBuffer, &nByte, /* Output vars */ | |
225 &pCsr->aChar[iStart], iEnd-iStart, /* Input vars */ | |
226 &status /* Output success/failure */ | |
227 ); | |
228 } while( nByte>pCsr->nBuffer ); | |
229 | |
230 *ppToken = pCsr->zBuffer; | |
231 *pnBytes = nByte; | |
232 *piStartOffset = pCsr->aOffset[iStart]; | |
233 *piEndOffset = pCsr->aOffset[iEnd]; | |
234 *piPosition = pCsr->iToken++; | |
235 | |
236 return SQLITE_OK; | |
237 } | |
238 | |
239 /* | |
240 ** The set of routines that implement the simple tokenizer | |
241 */ | |
242 static const sqlite3_tokenizer_module icuTokenizerModule = { | |
243 0, /* iVersion */ | |
244 icuCreate, /* xCreate */ | |
245 icuDestroy, /* xCreate */ | |
246 icuOpen, /* xOpen */ | |
247 icuClose, /* xClose */ | |
248 icuNext, /* xNext */ | |
249 }; | |
250 | |
251 /* | |
252 ** Set *ppModule to point at the implementation of the ICU tokenizer. | |
253 */ | |
254 void sqlite3Fts3IcuTokenizerModule( | |
255 sqlite3_tokenizer_module const**ppModule | |
256 ){ | |
257 *ppModule = &icuTokenizerModule; | |
258 } | |
259 | |
260 #endif /* defined(SQLITE_ENABLE_ICU) */ | |
261 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */ | |
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