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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 fts2 based on the ICU library. |
| 13 ** |
| 14 ** $Id: fts2_icu.c,v 1.3 2008/12/18 05:30:26 danielk1977 Exp $ |
| 15 */ |
| 16 |
| 17 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) |
| 18 #ifdef SQLITE_ENABLE_ICU |
| 19 |
| 20 #include <assert.h> |
| 21 #include <string.h> |
| 22 #include "fts2_tokenizer.h" |
| 23 |
| 24 #include <unicode/ubrk.h> |
| 25 #include <unicode/ucol.h> |
| 26 #include <unicode/ustring.h> |
| 27 #include <unicode/utf16.h> |
| 28 |
| 29 typedef struct IcuTokenizer IcuTokenizer; |
| 30 typedef struct IcuCursor IcuCursor; |
| 31 |
| 32 struct IcuTokenizer { |
| 33 sqlite3_tokenizer base; |
| 34 char *zLocale; |
| 35 }; |
| 36 |
| 37 struct IcuCursor { |
| 38 sqlite3_tokenizer_cursor base; |
| 39 |
| 40 UBreakIterator *pIter; /* ICU break-iterator object */ |
| 41 int nChar; /* Number of UChar elements in pInput */ |
| 42 UChar *aChar; /* Copy of input using utf-16 encoding */ |
| 43 int *aOffset; /* Offsets of each character in utf-8 input */ |
| 44 |
| 45 int nBuffer; |
| 46 char *zBuffer; |
| 47 |
| 48 int iToken; |
| 49 }; |
| 50 |
| 51 /* |
| 52 ** Create a new tokenizer instance. |
| 53 */ |
| 54 static int icuCreate( |
| 55 int argc, /* Number of entries in argv[] */ |
| 56 const char * const *argv, /* Tokenizer creation arguments */ |
| 57 sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */ |
| 58 ){ |
| 59 IcuTokenizer *p; |
| 60 int n = 0; |
| 61 |
| 62 if( argc>0 ){ |
| 63 n = strlen(argv[0])+1; |
| 64 } |
| 65 p = (IcuTokenizer *)sqlite3_malloc(sizeof(IcuTokenizer)+n); |
| 66 if( !p ){ |
| 67 return SQLITE_NOMEM; |
| 68 } |
| 69 memset(p, 0, sizeof(IcuTokenizer)); |
| 70 |
| 71 if( n ){ |
| 72 p->zLocale = (char *)&p[1]; |
| 73 memcpy(p->zLocale, argv[0], n); |
| 74 } |
| 75 |
| 76 *ppTokenizer = (sqlite3_tokenizer *)p; |
| 77 |
| 78 return SQLITE_OK; |
| 79 } |
| 80 |
| 81 /* |
| 82 ** Destroy a tokenizer |
| 83 */ |
| 84 static int icuDestroy(sqlite3_tokenizer *pTokenizer){ |
| 85 IcuTokenizer *p = (IcuTokenizer *)pTokenizer; |
| 86 sqlite3_free(p); |
| 87 return SQLITE_OK; |
| 88 } |
| 89 |
| 90 /* |
| 91 ** Prepare to begin tokenizing a particular string. The input |
| 92 ** string to be tokenized is pInput[0..nBytes-1]. A cursor |
| 93 ** used to incrementally tokenize this string is returned in |
| 94 ** *ppCursor. |
| 95 */ |
| 96 static int icuOpen( |
| 97 sqlite3_tokenizer *pTokenizer, /* The tokenizer */ |
| 98 const char *zInput, /* Input string */ |
| 99 int nInput, /* Length of zInput in bytes */ |
| 100 sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */ |
| 101 ){ |
| 102 IcuTokenizer *p = (IcuTokenizer *)pTokenizer; |
| 103 IcuCursor *pCsr; |
| 104 |
| 105 const int32_t opt = U_FOLD_CASE_DEFAULT; |
| 106 UErrorCode status = U_ZERO_ERROR; |
| 107 int nChar; |
| 108 |
| 109 UChar32 c; |
| 110 int iInput = 0; |
| 111 int iOut = 0; |
| 112 |
| 113 *ppCursor = 0; |
| 114 |
| 115 if( nInput<0 ){ |
| 116 nInput = strlen(zInput); |
| 117 } |
| 118 nChar = nInput+1; |
| 119 pCsr = (IcuCursor *)sqlite3_malloc( |
| 120 sizeof(IcuCursor) + /* IcuCursor */ |
| 121 (nChar+1) * sizeof(int) + /* IcuCursor.aOffset[] */ |
| 122 nChar * sizeof(UChar) /* IcuCursor.aChar[] */ |
| 123 ); |
| 124 if( !pCsr ){ |
| 125 return SQLITE_NOMEM; |
| 126 } |
| 127 memset(pCsr, 0, sizeof(IcuCursor)); |
| 128 pCsr->aOffset = (int *)&pCsr[1]; |
| 129 pCsr->aChar = (UChar *)&pCsr->aOffset[nChar+1]; |
| 130 |
| 131 pCsr->aOffset[iOut] = iInput; |
| 132 U8_NEXT(zInput, iInput, nInput, c); |
| 133 while( c>0 ){ |
| 134 int isError = 0; |
| 135 c = u_foldCase(c, opt); |
| 136 U16_APPEND(pCsr->aChar, iOut, nChar, c, isError); |
| 137 if( isError ){ |
| 138 sqlite3_free(pCsr); |
| 139 return SQLITE_ERROR; |
| 140 } |
| 141 pCsr->aOffset[iOut] = iInput; |
| 142 |
| 143 if( iInput<nInput ){ |
| 144 U8_NEXT(zInput, iInput, nInput, c); |
| 145 }else{ |
| 146 c = 0; |
| 147 } |
| 148 } |
| 149 |
| 150 pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status); |
| 151 if( !U_SUCCESS(status) ){ |
| 152 sqlite3_free(pCsr); |
| 153 return SQLITE_ERROR; |
| 154 } |
| 155 pCsr->nChar = iOut; |
| 156 |
| 157 ubrk_first(pCsr->pIter); |
| 158 *ppCursor = (sqlite3_tokenizer_cursor *)pCsr; |
| 159 return SQLITE_OK; |
| 160 } |
| 161 |
| 162 /* |
| 163 ** Close a tokenization cursor previously opened by a call to icuOpen(). |
| 164 */ |
| 165 static int icuClose(sqlite3_tokenizer_cursor *pCursor){ |
| 166 IcuCursor *pCsr = (IcuCursor *)pCursor; |
| 167 ubrk_close(pCsr->pIter); |
| 168 sqlite3_free(pCsr->zBuffer); |
| 169 sqlite3_free(pCsr); |
| 170 return SQLITE_OK; |
| 171 } |
| 172 |
| 173 /* |
| 174 ** Extract the next token from a tokenization cursor. |
| 175 */ |
| 176 static int icuNext( |
| 177 sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */ |
| 178 const char **ppToken, /* OUT: *ppToken is the token text */ |
| 179 int *pnBytes, /* OUT: Number of bytes in token */ |
| 180 int *piStartOffset, /* OUT: Starting offset of token */ |
| 181 int *piEndOffset, /* OUT: Ending offset of token */ |
| 182 int *piPosition /* OUT: Position integer of token */ |
| 183 ){ |
| 184 IcuCursor *pCsr = (IcuCursor *)pCursor; |
| 185 |
| 186 int iStart = 0; |
| 187 int iEnd = 0; |
| 188 int nByte = 0; |
| 189 |
| 190 while( iStart==iEnd ){ |
| 191 UChar32 c; |
| 192 |
| 193 iStart = ubrk_current(pCsr->pIter); |
| 194 iEnd = ubrk_next(pCsr->pIter); |
| 195 if( iEnd==UBRK_DONE ){ |
| 196 return SQLITE_DONE; |
| 197 } |
| 198 |
| 199 while( iStart<iEnd ){ |
| 200 int iWhite = iStart; |
| 201 U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c); |
| 202 if( u_isspace(c) ){ |
| 203 iStart = iWhite; |
| 204 }else{ |
| 205 break; |
| 206 } |
| 207 } |
| 208 assert(iStart<=iEnd); |
| 209 } |
| 210 |
| 211 do { |
| 212 UErrorCode status = U_ZERO_ERROR; |
| 213 if( nByte ){ |
| 214 char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte); |
| 215 if( !zNew ){ |
| 216 return SQLITE_NOMEM; |
| 217 } |
| 218 pCsr->zBuffer = zNew; |
| 219 pCsr->nBuffer = nByte; |
| 220 } |
| 221 |
| 222 u_strToUTF8( |
| 223 pCsr->zBuffer, pCsr->nBuffer, &nByte, /* Output vars */ |
| 224 &pCsr->aChar[iStart], iEnd-iStart, /* Input vars */ |
| 225 &status /* Output success/failure */ |
| 226 ); |
| 227 } while( nByte>pCsr->nBuffer ); |
| 228 |
| 229 *ppToken = pCsr->zBuffer; |
| 230 *pnBytes = nByte; |
| 231 *piStartOffset = pCsr->aOffset[iStart]; |
| 232 *piEndOffset = pCsr->aOffset[iEnd]; |
| 233 *piPosition = pCsr->iToken++; |
| 234 |
| 235 return SQLITE_OK; |
| 236 } |
| 237 |
| 238 /* |
| 239 ** The set of routines that implement the simple tokenizer |
| 240 */ |
| 241 static const sqlite3_tokenizer_module icuTokenizerModule = { |
| 242 0, /* iVersion */ |
| 243 icuCreate, /* xCreate */ |
| 244 icuDestroy, /* xCreate */ |
| 245 icuOpen, /* xOpen */ |
| 246 icuClose, /* xClose */ |
| 247 icuNext, /* xNext */ |
| 248 }; |
| 249 |
| 250 /* |
| 251 ** Set *ppModule to point at the implementation of the ICU tokenizer. |
| 252 */ |
| 253 void sqlite3Fts2IcuTokenizerModule( |
| 254 sqlite3_tokenizer_module const**ppModule |
| 255 ){ |
| 256 *ppModule = &icuTokenizerModule; |
| 257 } |
| 258 |
| 259 #endif /* defined(SQLITE_ENABLE_ICU) */ |
| 260 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */ |
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