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