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Diffstat (limited to '')
| -rw-r--r-- | ext/fts2/fts2_icu.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/ext/fts2/fts2_icu.c b/ext/fts2/fts2_icu.c new file mode 100644 index 0000000..2670301 --- /dev/null +++ b/ext/fts2/fts2_icu.c @@ -0,0 +1,260 @@ +/* +** 2007 June 22 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file implements a tokenizer for fts2 based on the ICU library. +** +** $Id: fts2_icu.c,v 1.3 2008/12/18 05:30:26 danielk1977 Exp $ +*/ + +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) +#ifdef SQLITE_ENABLE_ICU + +#include <assert.h> +#include <string.h> +#include "fts2_tokenizer.h" + +#include <unicode/ubrk.h> +#include <unicode/ucol.h> +#include <unicode/ustring.h> +#include <unicode/utf16.h> + +typedef struct IcuTokenizer IcuTokenizer; +typedef struct IcuCursor IcuCursor; + +struct IcuTokenizer { + sqlite3_tokenizer base; + char *zLocale; +}; + +struct IcuCursor { + sqlite3_tokenizer_cursor base; + + UBreakIterator *pIter; /* ICU break-iterator object */ + int nChar; /* Number of UChar elements in pInput */ + UChar *aChar; /* Copy of input using utf-16 encoding */ + int *aOffset; /* Offsets of each character in utf-8 input */ + + int nBuffer; + char *zBuffer; + + int iToken; +}; + +/* +** Create a new tokenizer instance. +*/ +static int icuCreate( + int argc, /* Number of entries in argv[] */ + const char * const *argv, /* Tokenizer creation arguments */ + sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */ +){ + IcuTokenizer *p; + int n = 0; + + if( argc>0 ){ + n = strlen(argv[0])+1; + } + p = (IcuTokenizer *)sqlite3_malloc(sizeof(IcuTokenizer)+n); + if( !p ){ + return SQLITE_NOMEM; + } + memset(p, 0, sizeof(IcuTokenizer)); + + if( n ){ + p->zLocale = (char *)&p[1]; + memcpy(p->zLocale, argv[0], n); + } + + *ppTokenizer = (sqlite3_tokenizer *)p; + + return SQLITE_OK; +} + +/* +** Destroy a tokenizer +*/ +static int icuDestroy(sqlite3_tokenizer *pTokenizer){ + IcuTokenizer *p = (IcuTokenizer *)pTokenizer; + sqlite3_free(p); + return SQLITE_OK; +} + +/* +** Prepare to begin tokenizing a particular string. The input +** string to be tokenized is pInput[0..nBytes-1]. A cursor +** used to incrementally tokenize this string is returned in +** *ppCursor. +*/ +static int icuOpen( + sqlite3_tokenizer *pTokenizer, /* The tokenizer */ + const char *zInput, /* Input string */ + int nInput, /* Length of zInput in bytes */ + sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */ +){ + IcuTokenizer *p = (IcuTokenizer *)pTokenizer; + IcuCursor *pCsr; + + const int32_t opt = U_FOLD_CASE_DEFAULT; + UErrorCode status = U_ZERO_ERROR; + int nChar; + + UChar32 c; + int iInput = 0; + int iOut = 0; + + *ppCursor = 0; + + if( nInput<0 ){ + nInput = strlen(zInput); + } + nChar = nInput+1; + pCsr = (IcuCursor *)sqlite3_malloc( + sizeof(IcuCursor) + /* IcuCursor */ + ((nChar+3)&~3) * sizeof(UChar) + /* IcuCursor.aChar[] */ + (nChar+1) * sizeof(int) /* IcuCursor.aOffset[] */ + ); + if( !pCsr ){ + return SQLITE_NOMEM; + } + memset(pCsr, 0, sizeof(IcuCursor)); + pCsr->aChar = (UChar *)&pCsr[1]; + pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3]; + + pCsr->aOffset[iOut] = iInput; + U8_NEXT(zInput, iInput, nInput, c); + while( c>0 ){ + int isError = 0; + c = u_foldCase(c, opt); + U16_APPEND(pCsr->aChar, iOut, nChar, c, isError); + if( isError ){ + sqlite3_free(pCsr); + return SQLITE_ERROR; + } + pCsr->aOffset[iOut] = iInput; + + if( iInput<nInput ){ + U8_NEXT(zInput, iInput, nInput, c); + }else{ + c = 0; + } + } + + pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status); + if( !U_SUCCESS(status) ){ + sqlite3_free(pCsr); + return SQLITE_ERROR; + } + pCsr->nChar = iOut; + + ubrk_first(pCsr->pIter); + *ppCursor = (sqlite3_tokenizer_cursor *)pCsr; + return SQLITE_OK; +} + +/* +** Close a tokenization cursor previously opened by a call to icuOpen(). +*/ +static int icuClose(sqlite3_tokenizer_cursor *pCursor){ + IcuCursor *pCsr = (IcuCursor *)pCursor; + ubrk_close(pCsr->pIter); + sqlite3_free(pCsr->zBuffer); + sqlite3_free(pCsr); + return SQLITE_OK; +} + +/* +** Extract the next token from a tokenization cursor. +*/ +static int icuNext( + sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */ + const char **ppToken, /* OUT: *ppToken is the token text */ + int *pnBytes, /* OUT: Number of bytes in token */ + int *piStartOffset, /* OUT: Starting offset of token */ + int *piEndOffset, /* OUT: Ending offset of token */ + int *piPosition /* OUT: Position integer of token */ +){ + IcuCursor *pCsr = (IcuCursor *)pCursor; + + int iStart = 0; + int iEnd = 0; + int nByte = 0; + + while( iStart==iEnd ){ + UChar32 c; + + iStart = ubrk_current(pCsr->pIter); + iEnd = ubrk_next(pCsr->pIter); + if( iEnd==UBRK_DONE ){ + return SQLITE_DONE; + } + + while( iStart<iEnd ){ + int iWhite = iStart; + U8_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c); + if( u_isspace(c) ){ + iStart = iWhite; + }else{ + break; + } + } + assert(iStart<=iEnd); + } + + do { + UErrorCode status = U_ZERO_ERROR; + if( nByte ){ + char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte); + if( !zNew ){ + return SQLITE_NOMEM; + } + pCsr->zBuffer = zNew; + pCsr->nBuffer = nByte; + } + + u_strToUTF8( + pCsr->zBuffer, pCsr->nBuffer, &nByte, /* Output vars */ + &pCsr->aChar[iStart], iEnd-iStart, /* Input vars */ + &status /* Output success/failure */ + ); + } while( nByte>pCsr->nBuffer ); + + *ppToken = pCsr->zBuffer; + *pnBytes = nByte; + *piStartOffset = pCsr->aOffset[iStart]; + *piEndOffset = pCsr->aOffset[iEnd]; + *piPosition = pCsr->iToken++; + + return SQLITE_OK; +} + +/* +** The set of routines that implement the simple tokenizer +*/ +static const sqlite3_tokenizer_module icuTokenizerModule = { + 0, /* iVersion */ + icuCreate, /* xCreate */ + icuDestroy, /* xCreate */ + icuOpen, /* xOpen */ + icuClose, /* xClose */ + icuNext, /* xNext */ +}; + +/* +** Set *ppModule to point at the implementation of the ICU tokenizer. +*/ +void sqlite3Fts2IcuTokenizerModule( + sqlite3_tokenizer_module const**ppModule +){ + *ppModule = &icuTokenizerModule; +} + +#endif /* defined(SQLITE_ENABLE_ICU) */ +#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */ |