374 lines
11 KiB
C
374 lines
11 KiB
C
/*
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** 2011 Jan 27
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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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**
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** This file is not part of the production FTS code. It is only used for
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** testing. It contains a virtual table implementation that provides direct
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** access to the full-text index of an FTS table.
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*/
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#include "fts3Int.h"
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#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
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#ifdef SQLITE_TEST
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#include <string.h>
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#include <assert.h>
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#include <stdlib.h>
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typedef struct Fts3termTable Fts3termTable;
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typedef struct Fts3termCursor Fts3termCursor;
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struct Fts3termTable {
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sqlite3_vtab base; /* Base class used by SQLite core */
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int iIndex; /* Index for Fts3Table.aIndex[] */
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Fts3Table *pFts3Tab;
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};
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struct Fts3termCursor {
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sqlite3_vtab_cursor base; /* Base class used by SQLite core */
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Fts3MultiSegReader csr; /* Must be right after "base" */
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Fts3SegFilter filter;
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int isEof; /* True if cursor is at EOF */
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char *pNext;
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sqlite3_int64 iRowid; /* Current 'rowid' value */
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sqlite3_int64 iDocid; /* Current 'docid' value */
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int iCol; /* Current 'col' value */
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int iPos; /* Current 'pos' value */
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};
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/*
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** Schema of the terms table.
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*/
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#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, docid, col, pos)"
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/*
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** This function does all the work for both the xConnect and xCreate methods.
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** These tables have no persistent representation of their own, so xConnect
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** and xCreate are identical operations.
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*/
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static int fts3termConnectMethod(
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sqlite3 *db, /* Database connection */
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void *pCtx, /* Non-zero for an fts4prefix table */
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int argc, /* Number of elements in argv array */
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const char * const *argv, /* xCreate/xConnect argument array */
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sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
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char **pzErr /* OUT: sqlite3_malloc'd error message */
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){
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char const *zDb; /* Name of database (e.g. "main") */
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char const *zFts3; /* Name of fts3 table */
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int nDb; /* Result of strlen(zDb) */
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int nFts3; /* Result of strlen(zFts3) */
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int nByte; /* Bytes of space to allocate here */
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int rc; /* value returned by declare_vtab() */
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Fts3termTable *p; /* Virtual table object to return */
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int iIndex = 0;
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UNUSED_PARAMETER(pCtx);
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if( argc==5 ){
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iIndex = atoi(argv[4]);
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argc--;
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}
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/* The user should specify a single argument - the name of an fts3 table. */
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if( argc!=4 ){
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*pzErr = sqlite3_mprintf(
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"wrong number of arguments to fts4term constructor"
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);
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return SQLITE_ERROR;
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}
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zDb = argv[1];
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nDb = (int)strlen(zDb);
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zFts3 = argv[3];
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nFts3 = (int)strlen(zFts3);
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rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
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if( rc!=SQLITE_OK ) return rc;
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nByte = sizeof(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
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p = (Fts3termTable *)sqlite3_malloc(nByte);
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if( !p ) return SQLITE_NOMEM;
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memset(p, 0, nByte);
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p->pFts3Tab = (Fts3Table *)&p[1];
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p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
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p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
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p->pFts3Tab->db = db;
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p->pFts3Tab->nIndex = iIndex+1;
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p->iIndex = iIndex;
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memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
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memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
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sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
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*ppVtab = (sqlite3_vtab *)p;
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return SQLITE_OK;
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}
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/*
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** This function does the work for both the xDisconnect and xDestroy methods.
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** These tables have no persistent representation of their own, so xDisconnect
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** and xDestroy are identical operations.
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*/
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static int fts3termDisconnectMethod(sqlite3_vtab *pVtab){
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Fts3termTable *p = (Fts3termTable *)pVtab;
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Fts3Table *pFts3 = p->pFts3Tab;
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int i;
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/* Free any prepared statements held */
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for(i=0; i<SizeofArray(pFts3->aStmt); i++){
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sqlite3_finalize(pFts3->aStmt[i]);
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}
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sqlite3_free(pFts3->zSegmentsTbl);
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sqlite3_free(p);
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return SQLITE_OK;
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}
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#define FTS4AUX_EQ_CONSTRAINT 1
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#define FTS4AUX_GE_CONSTRAINT 2
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#define FTS4AUX_LE_CONSTRAINT 4
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/*
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** xBestIndex - Analyze a WHERE and ORDER BY clause.
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*/
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static int fts3termBestIndexMethod(
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sqlite3_vtab *pVTab,
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sqlite3_index_info *pInfo
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){
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UNUSED_PARAMETER(pVTab);
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/* This vtab naturally does "ORDER BY term, docid, col, pos". */
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if( pInfo->nOrderBy ){
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int i;
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for(i=0; i<pInfo->nOrderBy; i++){
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if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break;
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}
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if( i==pInfo->nOrderBy ){
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pInfo->orderByConsumed = 1;
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}
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}
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return SQLITE_OK;
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}
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/*
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** xOpen - Open a cursor.
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*/
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static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
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Fts3termCursor *pCsr; /* Pointer to cursor object to return */
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UNUSED_PARAMETER(pVTab);
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pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor));
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if( !pCsr ) return SQLITE_NOMEM;
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memset(pCsr, 0, sizeof(Fts3termCursor));
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*ppCsr = (sqlite3_vtab_cursor *)pCsr;
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return SQLITE_OK;
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}
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/*
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** xClose - Close a cursor.
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*/
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static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){
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Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
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Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
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sqlite3Fts3SegmentsClose(pFts3);
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sqlite3Fts3SegReaderFinish(&pCsr->csr);
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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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** xNext - Advance the cursor to the next row, if any.
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*/
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static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){
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Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
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Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
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int rc;
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sqlite3_int64 v;
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/* Increment our pretend rowid value. */
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pCsr->iRowid++;
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/* Advance to the next term in the full-text index. */
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if( pCsr->csr.aDoclist==0
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|| pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1]
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){
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rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
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if( rc!=SQLITE_ROW ){
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pCsr->isEof = 1;
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return rc;
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}
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pCsr->iCol = 0;
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pCsr->iPos = 0;
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pCsr->iDocid = 0;
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pCsr->pNext = pCsr->csr.aDoclist;
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/* Read docid */
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid);
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}
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
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if( v==0 ){
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
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pCsr->iDocid += v;
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
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pCsr->iCol = 0;
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pCsr->iPos = 0;
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}
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if( v==1 ){
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
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pCsr->iCol += (int)v;
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pCsr->iPos = 0;
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pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
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}
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pCsr->iPos += (int)(v - 2);
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return SQLITE_OK;
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}
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/*
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** xFilter - Initialize a cursor to point at the start of its data.
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*/
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static int fts3termFilterMethod(
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sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
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int idxNum, /* Strategy index */
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const char *idxStr, /* Unused */
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int nVal, /* Number of elements in apVal */
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sqlite3_value **apVal /* Arguments for the indexing scheme */
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){
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Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
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Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
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Fts3Table *pFts3 = p->pFts3Tab;
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int rc;
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UNUSED_PARAMETER(nVal);
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UNUSED_PARAMETER(idxNum);
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UNUSED_PARAMETER(idxStr);
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UNUSED_PARAMETER(apVal);
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assert( idxStr==0 && idxNum==0 );
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/* In case this cursor is being reused, close and zero it. */
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testcase(pCsr->filter.zTerm);
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sqlite3Fts3SegReaderFinish(&pCsr->csr);
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memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
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pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
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pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
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rc = sqlite3Fts3SegReaderCursor(pFts3, 0, p->iIndex, FTS3_SEGCURSOR_ALL,
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pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
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);
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if( rc==SQLITE_OK ){
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rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
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}
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if( rc==SQLITE_OK ){
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rc = fts3termNextMethod(pCursor);
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}
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return rc;
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}
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/*
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** xEof - Return true if the cursor is at EOF, or false otherwise.
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*/
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static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){
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Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
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return pCsr->isEof;
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}
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/*
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** xColumn - Return a column value.
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*/
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static int fts3termColumnMethod(
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sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
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sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */
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int iCol /* Index of column to read value from */
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){
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Fts3termCursor *p = (Fts3termCursor *)pCursor;
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assert( iCol>=0 && iCol<=3 );
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switch( iCol ){
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case 0:
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sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
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break;
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case 1:
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sqlite3_result_int64(pCtx, p->iDocid);
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break;
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case 2:
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sqlite3_result_int64(pCtx, p->iCol);
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break;
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default:
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sqlite3_result_int64(pCtx, p->iPos);
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break;
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}
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return SQLITE_OK;
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}
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/*
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** xRowid - Return the current rowid for the cursor.
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*/
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static int fts3termRowidMethod(
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sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
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sqlite_int64 *pRowid /* OUT: Rowid value */
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){
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Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
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*pRowid = pCsr->iRowid;
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return SQLITE_OK;
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}
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/*
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** Register the fts3term module with database connection db. Return SQLITE_OK
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** if successful or an error code if sqlite3_create_module() fails.
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*/
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int sqlite3Fts3InitTerm(sqlite3 *db){
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static const sqlite3_module fts3term_module = {
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0, /* iVersion */
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fts3termConnectMethod, /* xCreate */
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fts3termConnectMethod, /* xConnect */
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fts3termBestIndexMethod, /* xBestIndex */
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fts3termDisconnectMethod, /* xDisconnect */
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fts3termDisconnectMethod, /* xDestroy */
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fts3termOpenMethod, /* xOpen */
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fts3termCloseMethod, /* xClose */
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fts3termFilterMethod, /* xFilter */
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fts3termNextMethod, /* xNext */
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fts3termEofMethod, /* xEof */
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fts3termColumnMethod, /* xColumn */
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fts3termRowidMethod, /* xRowid */
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0, /* xUpdate */
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0, /* xBegin */
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0, /* xSync */
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0, /* xCommit */
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0, /* xRollback */
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0, /* xFindFunction */
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0, /* xRename */
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0, /* xSavepoint */
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0, /* xRelease */
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0 /* xRollbackTo */
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};
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int rc; /* Return code */
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rc = sqlite3_create_module(db, "fts4term", &fts3term_module, 0);
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return rc;
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}
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#endif
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#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
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