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Diffstat (limited to 'ext/fts3/fts3_unicode.c')
| -rw-r--r-- | ext/fts3/fts3_unicode.c | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/ext/fts3/fts3_unicode.c b/ext/fts3/fts3_unicode.c new file mode 100644 index 0000000..79941ed --- /dev/null +++ b/ext/fts3/fts3_unicode.c @@ -0,0 +1,393 @@ +/* +** 2012 May 24 +** +** 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. +** +****************************************************************************** +** +** Implementation of the "unicode" full-text-search tokenizer. +*/ + +#ifdef SQLITE_ENABLE_FTS4_UNICODE61 + +#include "fts3Int.h" +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) + +#include <assert.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +#include "fts3_tokenizer.h" + +/* +** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied +** from the sqlite3 source file utf.c. If this file is compiled as part +** of the amalgamation, they are not required. +*/ +#ifndef SQLITE_AMALGAMATION + +static const unsigned char sqlite3Utf8Trans1[] = { + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, + 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00, +}; + +#define READ_UTF8(zIn, zTerm, c) \ + c = *(zIn++); \ + if( c>=0xc0 ){ \ + c = sqlite3Utf8Trans1[c-0xc0]; \ + while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){ \ + c = (c<<6) + (0x3f & *(zIn++)); \ + } \ + if( c<0x80 \ + || (c&0xFFFFF800)==0xD800 \ + || (c&0xFFFFFFFE)==0xFFFE ){ c = 0xFFFD; } \ + } + +#define WRITE_UTF8(zOut, c) { \ + if( c<0x00080 ){ \ + *zOut++ = (u8)(c&0xFF); \ + } \ + else if( c<0x00800 ){ \ + *zOut++ = 0xC0 + (u8)((c>>6)&0x1F); \ + *zOut++ = 0x80 + (u8)(c & 0x3F); \ + } \ + else if( c<0x10000 ){ \ + *zOut++ = 0xE0 + (u8)((c>>12)&0x0F); \ + *zOut++ = 0x80 + (u8)((c>>6) & 0x3F); \ + *zOut++ = 0x80 + (u8)(c & 0x3F); \ + }else{ \ + *zOut++ = 0xF0 + (u8)((c>>18) & 0x07); \ + *zOut++ = 0x80 + (u8)((c>>12) & 0x3F); \ + *zOut++ = 0x80 + (u8)((c>>6) & 0x3F); \ + *zOut++ = 0x80 + (u8)(c & 0x3F); \ + } \ +} + +#endif /* ifndef SQLITE_AMALGAMATION */ + +typedef struct unicode_tokenizer unicode_tokenizer; +typedef struct unicode_cursor unicode_cursor; + +struct unicode_tokenizer { + sqlite3_tokenizer base; + int bRemoveDiacritic; + int nException; + int *aiException; +}; + +struct unicode_cursor { + sqlite3_tokenizer_cursor base; + const unsigned char *aInput; /* Input text being tokenized */ + int nInput; /* Size of aInput[] in bytes */ + int iOff; /* Current offset within aInput[] */ + int iToken; /* Index of next token to be returned */ + char *zToken; /* storage for current token */ + int nAlloc; /* space allocated at zToken */ +}; + + +/* +** Destroy a tokenizer allocated by unicodeCreate(). +*/ +static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){ + if( pTokenizer ){ + unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer; + sqlite3_free(p->aiException); + sqlite3_free(p); + } + return SQLITE_OK; +} + +/* +** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE +** statement has specified that the tokenizer for this table shall consider +** all characters in string zIn/nIn to be separators (if bAlnum==0) or +** token characters (if bAlnum==1). +** +** For each codepoint in the zIn/nIn string, this function checks if the +** sqlite3FtsUnicodeIsalnum() function already returns the desired result. +** If so, no action is taken. Otherwise, the codepoint is added to the +** unicode_tokenizer.aiException[] array. For the purposes of tokenization, +** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all +** codepoints in the aiException[] array. +** +** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic() +** identifies as a diacritic) occurs in the zIn/nIn string it is ignored. +** It is not possible to change the behaviour of the tokenizer with respect +** to these codepoints. +*/ +static int unicodeAddExceptions( + unicode_tokenizer *p, /* Tokenizer to add exceptions to */ + int bAlnum, /* Replace Isalnum() return value with this */ + const char *zIn, /* Array of characters to make exceptions */ + int nIn /* Length of z in bytes */ +){ + const unsigned char *z = (const unsigned char *)zIn; + const unsigned char *zTerm = &z[nIn]; + int iCode; + int nEntry = 0; + + assert( bAlnum==0 || bAlnum==1 ); + + while( z<zTerm ){ + READ_UTF8(z, zTerm, iCode); + assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 ); + if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum + && sqlite3FtsUnicodeIsdiacritic(iCode)==0 + ){ + nEntry++; + } + } + + if( nEntry ){ + int *aNew; /* New aiException[] array */ + int nNew; /* Number of valid entries in array aNew[] */ + + aNew = sqlite3_realloc(p->aiException, (p->nException+nEntry)*sizeof(int)); + if( aNew==0 ) return SQLITE_NOMEM; + nNew = p->nException; + + z = (const unsigned char *)zIn; + while( z<zTerm ){ + READ_UTF8(z, zTerm, iCode); + if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum + && sqlite3FtsUnicodeIsdiacritic(iCode)==0 + ){ + int i, j; + for(i=0; i<nNew && aNew[i]<iCode; i++); + for(j=nNew; j>i; j--) aNew[j] = aNew[j-1]; + aNew[i] = iCode; + nNew++; + } + } + p->aiException = aNew; + p->nException = nNew; + } + + return SQLITE_OK; +} + +/* +** Return true if the p->aiException[] array contains the value iCode. +*/ +static int unicodeIsException(unicode_tokenizer *p, int iCode){ + if( p->nException>0 ){ + int *a = p->aiException; + int iLo = 0; + int iHi = p->nException-1; + + while( iHi>=iLo ){ + int iTest = (iHi + iLo) / 2; + if( iCode==a[iTest] ){ + return 1; + }else if( iCode>a[iTest] ){ + iLo = iTest+1; + }else{ + iHi = iTest-1; + } + } + } + + return 0; +} + +/* +** Return true if, for the purposes of tokenization, codepoint iCode is +** considered a token character (not a separator). +*/ +static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){ + assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 ); + return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode); +} + +/* +** Create a new tokenizer instance. +*/ +static int unicodeCreate( + int nArg, /* Size of array argv[] */ + const char * const *azArg, /* Tokenizer creation arguments */ + sqlite3_tokenizer **pp /* OUT: New tokenizer handle */ +){ + unicode_tokenizer *pNew; /* New tokenizer object */ + int i; + int rc = SQLITE_OK; + + pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer)); + if( pNew==NULL ) return SQLITE_NOMEM; + memset(pNew, 0, sizeof(unicode_tokenizer)); + pNew->bRemoveDiacritic = 1; + + for(i=0; rc==SQLITE_OK && i<nArg; i++){ + const char *z = azArg[i]; + int n = strlen(z); + + if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){ + pNew->bRemoveDiacritic = 1; + } + else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){ + pNew->bRemoveDiacritic = 0; + } + else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){ + rc = unicodeAddExceptions(pNew, 1, &z[11], n-11); + } + else if( n>=11 && memcmp("separators=", z, 11)==0 ){ + rc = unicodeAddExceptions(pNew, 0, &z[11], n-11); + } + else{ + /* Unrecognized argument */ + rc = SQLITE_ERROR; + } + } + + if( rc!=SQLITE_OK ){ + unicodeDestroy((sqlite3_tokenizer *)pNew); + pNew = 0; + } + *pp = (sqlite3_tokenizer *)pNew; + return rc; +} + +/* +** 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 unicodeOpen( + sqlite3_tokenizer *p, /* The tokenizer */ + const char *aInput, /* Input string */ + int nInput, /* Size of string aInput in bytes */ + sqlite3_tokenizer_cursor **pp /* OUT: New cursor object */ +){ + unicode_cursor *pCsr; + + pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor)); + if( pCsr==0 ){ + return SQLITE_NOMEM; + } + memset(pCsr, 0, sizeof(unicode_cursor)); + + pCsr->aInput = (const unsigned char *)aInput; + if( aInput==0 ){ + pCsr->nInput = 0; + }else if( nInput<0 ){ + pCsr->nInput = (int)strlen(aInput); + }else{ + pCsr->nInput = nInput; + } + + *pp = &pCsr->base; + UNUSED_PARAMETER(p); + return SQLITE_OK; +} + +/* +** Close a tokenization cursor previously opened by a call to +** simpleOpen() above. +*/ +static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){ + unicode_cursor *pCsr = (unicode_cursor *) pCursor; + sqlite3_free(pCsr->zToken); + sqlite3_free(pCsr); + return SQLITE_OK; +} + +/* +** Extract the next token from a tokenization cursor. The cursor must +** have been opened by a prior call to simpleOpen(). +*/ +static int unicodeNext( + sqlite3_tokenizer_cursor *pC, /* Cursor returned by simpleOpen */ + const char **paToken, /* OUT: Token text */ + int *pnToken, /* OUT: Number of bytes at *paToken */ + int *piStart, /* OUT: Starting offset of token */ + int *piEnd, /* OUT: Ending offset of token */ + int *piPos /* OUT: Position integer of token */ +){ + unicode_cursor *pCsr = (unicode_cursor *)pC; + unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer); + int iCode; + char *zOut; + const unsigned char *z = &pCsr->aInput[pCsr->iOff]; + const unsigned char *zStart = z; + const unsigned char *zEnd; + const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput]; + + /* Scan past any delimiter characters before the start of the next token. + ** Return SQLITE_DONE early if this takes us all the way to the end of + ** the input. */ + while( z<zTerm ){ + READ_UTF8(z, zTerm, iCode); + if( unicodeIsAlnum(p, iCode) ) break; + zStart = z; + } + if( zStart>=zTerm ) return SQLITE_DONE; + + zOut = pCsr->zToken; + do { + int iOut; + + /* Grow the output buffer if required. */ + if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){ + char *zNew = sqlite3_realloc(pCsr->zToken, pCsr->nAlloc+64); + if( !zNew ) return SQLITE_NOMEM; + zOut = &zNew[zOut - pCsr->zToken]; + pCsr->zToken = zNew; + pCsr->nAlloc += 64; + } + + /* Write the folded case of the last character read to the output */ + zEnd = z; + iOut = sqlite3FtsUnicodeFold(iCode, p->bRemoveDiacritic); + if( iOut ){ + WRITE_UTF8(zOut, iOut); + } + + /* If the cursor is not at EOF, read the next character */ + if( z>=zTerm ) break; + READ_UTF8(z, zTerm, iCode); + }while( unicodeIsAlnum(p, iCode) + || sqlite3FtsUnicodeIsdiacritic(iCode) + ); + + /* Set the output variables and return. */ + pCsr->iOff = (z - pCsr->aInput); + *paToken = pCsr->zToken; + *pnToken = zOut - pCsr->zToken; + *piStart = (zStart - pCsr->aInput); + *piEnd = (zEnd - pCsr->aInput); + *piPos = pCsr->iToken++; + return SQLITE_OK; +} + +/* +** Set *ppModule to a pointer to the sqlite3_tokenizer_module +** structure for the unicode tokenizer. +*/ +void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){ + static const sqlite3_tokenizer_module module = { + 0, + unicodeCreate, + unicodeDestroy, + unicodeOpen, + unicodeClose, + unicodeNext, + 0, + }; + *ppModule = &module; +} + +#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */ +#endif /* ifndef SQLITE_ENABLE_FTS4_UNICODE61 */ |