[sql] Import reference version of SQLite 3.17..

third_party/sqlite/sqlite-src-3170000/ext/fts5/fts5_main.c

+/*
+** 2014 Jun 09
+**
+** 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 is an SQLite module implementing full-text search.
+*/
+
+
+#include "fts5Int.h"
+
+/*
+** This variable is set to false when running tests for which the on disk
+** structures should not be corrupt. Otherwise, true. If it is false, extra
+** assert() conditions in the fts5 code are activated - conditions that are
+** only true if it is guaranteed that the fts5 database is not corrupt.
+*/
+int sqlite3_fts5_may_be_corrupt = 1;
+
+
+typedef struct Fts5Auxdata Fts5Auxdata;
+typedef struct Fts5Auxiliary Fts5Auxiliary;
+typedef struct Fts5Cursor Fts5Cursor;
+typedef struct Fts5Sorter Fts5Sorter;
+typedef struct Fts5Table Fts5Table;
+typedef struct Fts5TokenizerModule Fts5TokenizerModule;
+
+/*
+** NOTES ON TRANSACTIONS: 
+**
+** SQLite invokes the following virtual table methods as transactions are 
+** opened and closed by the user:
+**
+**     xBegin():    Start of a new transaction.
+**     xSync():     Initial part of two-phase commit.
+**     xCommit():   Final part of two-phase commit.
+**     xRollback(): Rollback the transaction.
+**
+** Anything that is required as part of a commit that may fail is performed
+** in the xSync() callback. Current versions of SQLite ignore any errors 
+** returned by xCommit().
+**
+** And as sub-transactions are opened/closed:
+**
+**     xSavepoint(int S):  Open savepoint S.
+**     xRelease(int S):    Commit and close savepoint S.
+**     xRollbackTo(int S): Rollback to start of savepoint S.
+**
+** During a write-transaction the fts5_index.c module may cache some data 
+** in-memory. It is flushed to disk whenever xSync(), xRelease() or
+** xSavepoint() is called. And discarded whenever xRollback() or xRollbackTo() 
+** is called.
+**
+** Additionally, if SQLITE_DEBUG is defined, an instance of the following
+** structure is used to record the current transaction state. This information
+** is not required, but it is used in the assert() statements executed by
+** function fts5CheckTransactionState() (see below).
+*/
+struct Fts5TransactionState {
+  int eState;                     /* 0==closed, 1==open, 2==synced */
+  int iSavepoint;                 /* Number of open savepoints (0 -> none) */
+};
+
+/*
+** A single object of this type is allocated when the FTS5 module is 
+** registered with a database handle. It is used to store pointers to
+** all registered FTS5 extensions - tokenizers and auxiliary functions.
+*/
+struct Fts5Global {
+  fts5_api api;                   /* User visible part of object (see fts5.h) */
+  sqlite3 *db;                    /* Associated database connection */ 
+  i64 iNextId;                    /* Used to allocate unique cursor ids */
+  Fts5Auxiliary *pAux;            /* First in list of all aux. functions */
+  Fts5TokenizerModule *pTok;      /* First in list of all tokenizer modules */
+  Fts5TokenizerModule *pDfltTok;  /* Default tokenizer module */
+  Fts5Cursor *pCsr;               /* First in list of all open cursors */
+};
+
+/*
+** Each auxiliary function registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pAux list.
+*/
+struct Fts5Auxiliary {
+  Fts5Global *pGlobal;            /* Global context for this function */
+  char *zFunc;                    /* Function name (nul-terminated) */
+  void *pUserData;                /* User-data pointer */
+  fts5_extension_function xFunc;  /* Callback function */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5Auxiliary *pNext;           /* Next registered auxiliary function */
+};
+
+/*
+** Each tokenizer module registered with the FTS5 module is represented
+** by an object of the following type. All such objects are stored as part
+** of the Fts5Global.pTok list.
+*/
+struct Fts5TokenizerModule {
+  char *zName;                    /* Name of tokenizer */
+  void *pUserData;                /* User pointer passed to xCreate() */
+  fts5_tokenizer x;               /* Tokenizer functions */
+  void (*xDestroy)(void*);        /* Destructor function */
+  Fts5TokenizerModule *pNext;     /* Next registered tokenizer module */
+};
+
+/*
+** Virtual-table object.
+*/
+struct Fts5Table {
+  sqlite3_vtab base;              /* Base class used by SQLite core */
+  Fts5Config *pConfig;            /* Virtual table configuration */
+  Fts5Index *pIndex;              /* Full-text index */
+  Fts5Storage *pStorage;          /* Document store */
+  Fts5Global *pGlobal;            /* Global (connection wide) data */
+  Fts5Cursor *pSortCsr;           /* Sort data from this cursor */
+#ifdef SQLITE_DEBUG
+  struct Fts5TransactionState ts;
+#endif
+};
+
+struct Fts5MatchPhrase {
+  Fts5Buffer *pPoslist;           /* Pointer to current poslist */
+  int nTerm;                      /* Size of phrase in terms */
+};
+
+/*
+** pStmt:
+**   SELECT rowid, <fts> FROM <fts> ORDER BY +rank;
+**
+** aIdx[]:
+**   There is one entry in the aIdx[] array for each phrase in the query,
+**   the value of which is the offset within aPoslist[] following the last 
+**   byte of the position list for the corresponding phrase.
+*/
+struct Fts5Sorter {
+  sqlite3_stmt *pStmt;
+  i64 iRowid;                     /* Current rowid */
+  const u8 *aPoslist;             /* Position lists for current row */
+  int nIdx;                       /* Number of entries in aIdx[] */
+  int aIdx[1];                    /* Offsets into aPoslist for current row */
+};
+
+
+/*
+** Virtual-table cursor object.
+**
+** iSpecial:
+**   If this is a 'special' query (refer to function fts5SpecialMatch()), 
+**   then this variable contains the result of the query. 
+**
+** iFirstRowid, iLastRowid:
+**   These variables are only used for FTS5_PLAN_MATCH cursors. Assuming the
+**   cursor iterates in ascending order of rowids, iFirstRowid is the lower
+**   limit of rowids to return, and iLastRowid the upper. In other words, the
+**   WHERE clause in the user's query might have been:
+**
+**       <tbl> MATCH <expr> AND rowid BETWEEN $iFirstRowid AND $iLastRowid
+**
+**   If the cursor iterates in descending order of rowid, iFirstRowid
+**   is the upper limit (i.e. the "first" rowid visited) and iLastRowid
+**   the lower.
+*/
+struct Fts5Cursor {
+  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
+  Fts5Cursor *pNext;              /* Next cursor in Fts5Cursor.pCsr list */
+  int *aColumnSize;               /* Values for xColumnSize() */
+  i64 iCsrId;                     /* Cursor id */
+
+  /* Zero from this point onwards on cursor reset */
+  int ePlan;                      /* FTS5_PLAN_XXX value */
+  int bDesc;                      /* True for "ORDER BY rowid DESC" queries */
+  i64 iFirstRowid;                /* Return no rowids earlier than this */
+  i64 iLastRowid;                 /* Return no rowids later than this */
+  sqlite3_stmt *pStmt;            /* Statement used to read %_content */
+  Fts5Expr *pExpr;                /* Expression for MATCH queries */
+  Fts5Sorter *pSorter;            /* Sorter for "ORDER BY rank" queries */
+  int csrflags;                   /* Mask of cursor flags (see below) */
+  i64 iSpecial;                   /* Result of special query */
+
+  /* "rank" function. Populated on demand from vtab.xColumn(). */
+  char *zRank;                    /* Custom rank function */
+  char *zRankArgs;                /* Custom rank function args */
+  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
+  int nRankArg;                   /* Number of trailing arguments for rank() */
+  sqlite3_value **apRankArg;      /* Array of trailing arguments */
+  sqlite3_stmt *pRankArgStmt;     /* Origin of objects in apRankArg[] */
+
+  /* Auxiliary data storage */
+  Fts5Auxiliary *pAux;            /* Currently executing extension function */
+  Fts5Auxdata *pAuxdata;          /* First in linked list of saved aux-data */
+
+  /* Cache used by auxiliary functions xInst() and xInstCount() */
+  Fts5PoslistReader *aInstIter;   /* One for each phrase */
+  int nInstAlloc;                 /* Size of aInst[] array (entries / 3) */
+  int nInstCount;                 /* Number of phrase instances */
+  int *aInst;                     /* 3 integers per phrase instance */
+};
+
+/*
+** Bits that make up the "idxNum" parameter passed indirectly by 
+** xBestIndex() to xFilter().
+*/
+#define FTS5_BI_MATCH        0x0001         /* <tbl> MATCH ? */
+#define FTS5_BI_RANK         0x0002         /* rank MATCH ? */
+#define FTS5_BI_ROWID_EQ     0x0004         /* rowid == ? */
+#define FTS5_BI_ROWID_LE     0x0008         /* rowid <= ? */
+#define FTS5_BI_ROWID_GE     0x0010         /* rowid >= ? */
+
+#define FTS5_BI_ORDER_RANK   0x0020
+#define FTS5_BI_ORDER_ROWID  0x0040
+#define FTS5_BI_ORDER_DESC   0x0080
+
+/*
+** Values for Fts5Cursor.csrflags
+*/
+#define FTS5CSR_EOF               0x01
+#define FTS5CSR_REQUIRE_CONTENT   0x02
+#define FTS5CSR_REQUIRE_DOCSIZE   0x04
+#define FTS5CSR_REQUIRE_INST      0x08
+#define FTS5CSR_FREE_ZRANK        0x10
+#define FTS5CSR_REQUIRE_RESEEK    0x20
+#define FTS5CSR_REQUIRE_POSLIST   0x40
+
+#define BitFlagAllTest(x,y) (((x) & (y))==(y))
+#define BitFlagTest(x,y)    (((x) & (y))!=0)
+
+
+/*
+** Macros to Set(), Clear() and Test() cursor flags.
+*/
+#define CsrFlagSet(pCsr, flag)   ((pCsr)->csrflags |= (flag))
+#define CsrFlagClear(pCsr, flag) ((pCsr)->csrflags &= ~(flag))
+#define CsrFlagTest(pCsr, flag)  ((pCsr)->csrflags & (flag))
+
+struct Fts5Auxdata {
+  Fts5Auxiliary *pAux;            /* Extension to which this belongs */
+  void *pPtr;                     /* Pointer value */
+  void(*xDelete)(void*);          /* Destructor */
+  Fts5Auxdata *pNext;             /* Next object in linked list */
+};
+
+#ifdef SQLITE_DEBUG
+#define FTS5_BEGIN      1
+#define FTS5_SYNC       2
+#define FTS5_COMMIT     3
+#define FTS5_ROLLBACK   4
+#define FTS5_SAVEPOINT  5
+#define FTS5_RELEASE    6
+#define FTS5_ROLLBACKTO 7
+static void fts5CheckTransactionState(Fts5Table *p, int op, int iSavepoint){
+  switch( op ){
+    case FTS5_BEGIN:
+      assert( p->ts.eState==0 );
+      p->ts.eState = 1;
+      p->ts.iSavepoint = -1;
+      break;
+
+    case FTS5_SYNC:
+      assert( p->ts.eState==1 );
+      p->ts.eState = 2;
+      break;
+
+    case FTS5_COMMIT:
+      assert( p->ts.eState==2 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_ROLLBACK:
+      assert( p->ts.eState==1 || p->ts.eState==2 || p->ts.eState==0 );
+      p->ts.eState = 0;
+      break;
+
+    case FTS5_SAVEPOINT:
+      assert( p->ts.eState==1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint>p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint;
+      break;
+      
+    case FTS5_RELEASE:
+      assert( p->ts.eState==1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint<=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint-1;
+      break;
+
+    case FTS5_ROLLBACKTO:
+      assert( p->ts.eState==1 );
+      assert( iSavepoint>=0 );
+      assert( iSavepoint<=p->ts.iSavepoint );
+      p->ts.iSavepoint = iSavepoint;
+      break;
+  }
+}
+#else
+# define fts5CheckTransactionState(x,y,z)
+#endif
+
+/*
+** Return true if pTab is a contentless table.
+*/
+static int fts5IsContentless(Fts5Table *pTab){
+  return pTab->pConfig->eContent==FTS5_CONTENT_NONE;
+}
+
+/*
+** Delete a virtual table handle allocated by fts5InitVtab(). 
+*/
+static void fts5FreeVtab(Fts5Table *pTab){
+  if( pTab ){
+    sqlite3Fts5IndexClose(pTab->pIndex);
+    sqlite3Fts5StorageClose(pTab->pStorage);
+    sqlite3Fts5ConfigFree(pTab->pConfig);
+    sqlite3_free(pTab);
+  }
+}
+
+/*
+** The xDisconnect() virtual table method.
+*/
+static int fts5DisconnectMethod(sqlite3_vtab *pVtab){
+  fts5FreeVtab((Fts5Table*)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** The xDestroy() virtual table method.
+*/
+static int fts5DestroyMethod(sqlite3_vtab *pVtab){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  int rc = sqlite3Fts5DropAll(pTab->pConfig);
+  if( rc==SQLITE_OK ){
+    fts5FreeVtab((Fts5Table*)pVtab);
+  }
+  return rc;
+}
+
+/*
+** This function is the implementation of both the xConnect and xCreate
+** methods of the FTS3 virtual table.
+**
+** The argv[] array contains the following:
+**
+**   argv[0]   -> module name  ("fts5")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int fts5InitVtab(
+  int bCreate,                    /* True for xCreate, false for xConnect */
+  sqlite3 *db,                    /* The SQLite database connection */
+  void *pAux,                     /* Hash table containing tokenizers */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
+  char **pzErr                    /* Write any error message here */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pAux;
+  const char **azConfig = (const char**)argv;
+  int rc = SQLITE_OK;             /* Return code */
+  Fts5Config *pConfig = 0;        /* Results of parsing argc/argv */
+  Fts5Table *pTab = 0;            /* New virtual table object */
+
+  /* Allocate the new vtab object and parse the configuration */
+  pTab = (Fts5Table*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Table));
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigParse(pGlobal, db, argc, azConfig, &pConfig, pzErr);
+    assert( (rc==SQLITE_OK && *pzErr==0) || pConfig==0 );
+  }
+  if( rc==SQLITE_OK ){
+    pTab->pConfig = pConfig;
+    pTab->pGlobal = pGlobal;
+  }
+
+  /* Open the index sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5IndexOpen(pConfig, bCreate, &pTab->pIndex, pzErr);
+  }
+
+  /* Open the storage sub-system */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageOpen(
+        pConfig, pTab->pIndex, bCreate, &pTab->pStorage, pzErr
+    );
+  }
+
+  /* Call sqlite3_declare_vtab() */
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5ConfigDeclareVtab(pConfig);
+  }
+
+  /* Load the initial configuration */
+  if( rc==SQLITE_OK ){
+    assert( pConfig->pzErrmsg==0 );
+    pConfig->pzErrmsg = pzErr;
+    rc = sqlite3Fts5IndexLoadConfig(pTab->pIndex);
+    sqlite3Fts5IndexRollback(pTab->pIndex);
+    pConfig->pzErrmsg = 0;
+  }
+
+  if( rc!=SQLITE_OK ){
+    fts5FreeVtab(pTab);
+    pTab = 0;
+  }else if( bCreate ){
+    fts5CheckTransactionState(pTab, FTS5_BEGIN, 0);
+  }
+  *ppVTab = (sqlite3_vtab*)pTab;
+  return rc;
+}
+
+/*
+** The xConnect() and xCreate() methods for the virtual table. All the
+** work is done in function fts5InitVtab().
+*/
+static int fts5ConnectMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
+}
+static int fts5CreateMethod(
+  sqlite3 *db,                    /* Database connection */
+  void *pAux,                     /* Pointer to tokenizer hash table */
+  int argc,                       /* Number of elements in argv array */
+  const char * const *argv,       /* xCreate/xConnect argument array */
+  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
+  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
+){
+  return fts5InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
+}
+
+/*
+** The different query plans.
+*/
+#define FTS5_PLAN_MATCH          1       /* (<tbl> MATCH ?) */
+#define FTS5_PLAN_SOURCE         2       /* A source cursor for SORTED_MATCH */
+#define FTS5_PLAN_SPECIAL        3       /* An internal query */
+#define FTS5_PLAN_SORTED_MATCH   4       /* (<tbl> MATCH ? ORDER BY rank) */
+#define FTS5_PLAN_SCAN           5       /* No usable constraint */
+#define FTS5_PLAN_ROWID          6       /* (rowid = ?) */
+
+/*
+** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
+** extension is currently being used by a version of SQLite too old to
+** support index-info flags. In that case this function is a no-op.
+*/
+static void fts5SetUniqueFlag(sqlite3_index_info *pIdxInfo){
+#if SQLITE_VERSION_NUMBER>=3008012
+#ifndef SQLITE_CORE
+  if( sqlite3_libversion_number()>=3008012 )
+#endif
+  {
+    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
+  }
+#endif
+}
+
+/*
+** Implementation of the xBestIndex method for FTS5 tables. Within the 
+** WHERE constraint, it searches for the following:
+**
+**   1. A MATCH constraint against the special column.
+**   2. A MATCH constraint against the "rank" column.
+**   3. An == constraint against the rowid column.
+**   4. A < or <= constraint against the rowid column.
+**   5. A > or >= constraint against the rowid column.
+**
+** Within the ORDER BY, either:
+**
+**   5. ORDER BY rank [ASC|DESC]
+**   6. ORDER BY rowid [ASC|DESC]
+**
+** Costs are assigned as follows:
+**
+**  a) If an unusable MATCH operator is present in the WHERE clause, the
+**     cost is unconditionally set to 1e50 (a really big number).
+**
+**  a) If a MATCH operator is present, the cost depends on the other
+**     constraints also present. As follows:
+**
+**       * No other constraints:         cost=1000.0
+**       * One rowid range constraint:   cost=750.0
+**       * Both rowid range constraints: cost=500.0
+**       * An == rowid constraint:       cost=100.0
+**
+**  b) Otherwise, if there is no MATCH:
+**
+**       * No other constraints:         cost=1000000.0
+**       * One rowid range constraint:   cost=750000.0
+**       * Both rowid range constraints: cost=250000.0
+**       * An == rowid constraint:       cost=10.0
+**
+** Costs are not modified by the ORDER BY clause.
+*/
+static int fts5BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
+  Fts5Table *pTab = (Fts5Table*)pVTab;
+  Fts5Config *pConfig = pTab->pConfig;
+  int idxFlags = 0;               /* Parameter passed through to xFilter() */
+  int bHasMatch;
+  int iNext;
+  int i;
+
+  struct Constraint {
+    int op;                       /* Mask against sqlite3_index_constraint.op */
+    int fts5op;                   /* FTS5 mask for idxFlags */
+    int iCol;                     /* 0==rowid, 1==tbl, 2==rank */
+    int omit;                     /* True to omit this if found */
+    int iConsIndex;               /* Index in pInfo->aConstraint[] */
+  } aConstraint[] = {
+    {SQLITE_INDEX_CONSTRAINT_MATCH|SQLITE_INDEX_CONSTRAINT_EQ, 
+                                    FTS5_BI_MATCH,    1, 1, -1},
+    {SQLITE_INDEX_CONSTRAINT_MATCH|SQLITE_INDEX_CONSTRAINT_EQ, 
+                                    FTS5_BI_RANK,     2, 1, -1},
+    {SQLITE_INDEX_CONSTRAINT_EQ,    FTS5_BI_ROWID_EQ, 0, 0, -1},
+    {SQLITE_INDEX_CONSTRAINT_LT|SQLITE_INDEX_CONSTRAINT_LE, 
+                                    FTS5_BI_ROWID_LE, 0, 0, -1},
+    {SQLITE_INDEX_CONSTRAINT_GT|SQLITE_INDEX_CONSTRAINT_GE, 
+                                    FTS5_BI_ROWID_GE, 0, 0, -1},
+  };
+
+  int aColMap[3];
+  aColMap[0] = -1;
+  aColMap[1] = pConfig->nCol;
+  aColMap[2] = pConfig->nCol+1;
+
+  /* Set idxFlags flags for all WHERE clause terms that will be used. */
+  for(i=0; i<pInfo->nConstraint; i++){
+    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
+    int j;
+    for(j=0; j<ArraySize(aConstraint); j++){
+      struct Constraint *pC = &aConstraint[j];
+      if( p->iColumn==aColMap[pC->iCol] && p->op & pC->op ){
+        if( p->usable ){
+          pC->iConsIndex = i;
+          idxFlags |= pC->fts5op;
+        }else if( j==0 ){
+          /* As there exists an unusable MATCH constraint this is an 
+          ** unusable plan. Set a prohibitively high cost. */
+          pInfo->estimatedCost = 1e50;
+          return SQLITE_OK;
+        }
+      }
+    }
+  }
+
+  /* Set idxFlags flags for the ORDER BY clause */
+  if( pInfo->nOrderBy==1 ){
+    int iSort = pInfo->aOrderBy[0].iColumn;
+    if( iSort==(pConfig->nCol+1) && BitFlagTest(idxFlags, FTS5_BI_MATCH) ){
+      idxFlags |= FTS5_BI_ORDER_RANK;
+    }else if( iSort==-1 ){
+      idxFlags |= FTS5_BI_ORDER_ROWID;
+    }
+    if( BitFlagTest(idxFlags, FTS5_BI_ORDER_RANK|FTS5_BI_ORDER_ROWID) ){
+      pInfo->orderByConsumed = 1;
+      if( pInfo->aOrderBy[0].desc ){
+        idxFlags |= FTS5_BI_ORDER_DESC;
+      }
+    }
+  }
+
+  /* Calculate the estimated cost based on the flags set in idxFlags. */
+  bHasMatch = BitFlagTest(idxFlags, FTS5_BI_MATCH);
+  if( BitFlagTest(idxFlags, FTS5_BI_ROWID_EQ) ){
+    pInfo->estimatedCost = bHasMatch ? 100.0 : 10.0;
+    if( bHasMatch==0 ) fts5SetUniqueFlag(pInfo);
+  }else if( BitFlagAllTest(idxFlags, FTS5_BI_ROWID_LE|FTS5_BI_ROWID_GE) ){
+    pInfo->estimatedCost = bHasMatch ? 500.0 : 250000.0;
+  }else if( BitFlagTest(idxFlags, FTS5_BI_ROWID_LE|FTS5_BI_ROWID_GE) ){
+    pInfo->estimatedCost = bHasMatch ? 750.0 : 750000.0;
+  }else{
+    pInfo->estimatedCost = bHasMatch ? 1000.0 : 1000000.0;
+  }
+
+  /* Assign argvIndex values to each constraint in use. */
+  iNext = 1;
+  for(i=0; i<ArraySize(aConstraint); i++){
+    struct Constraint *pC = &aConstraint[i];
+    if( pC->iConsIndex>=0 ){
+      pInfo->aConstraintUsage[pC->iConsIndex].argvIndex = iNext++;
+      pInfo->aConstraintUsage[pC->iConsIndex].omit = (unsigned char)pC->omit;
+    }
+  }
+
+  pInfo->idxNum = idxFlags;
+  return SQLITE_OK;
+}
+
+static int fts5NewTransaction(Fts5Table *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->base.pVtab==(sqlite3_vtab*)pTab ) return SQLITE_OK;
+  }
+  return sqlite3Fts5StorageReset(pTab->pStorage);
+}
+
+/*
+** Implementation of xOpen method.
+*/
+static int fts5OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+  Fts5Table *pTab = (Fts5Table*)pVTab;
+  Fts5Config *pConfig = pTab->pConfig;
+  Fts5Cursor *pCsr = 0;           /* New cursor object */
+  int nByte;                      /* Bytes of space to allocate */
+  int rc;                         /* Return code */
+
+  rc = fts5NewTransaction(pTab);
+  if( rc==SQLITE_OK ){
+    nByte = sizeof(Fts5Cursor) + pConfig->nCol * sizeof(int);
+    pCsr = (Fts5Cursor*)sqlite3_malloc(nByte);
+    if( pCsr ){
+      Fts5Global *pGlobal = pTab->pGlobal;
+      memset(pCsr, 0, nByte);
+      pCsr->aColumnSize = (int*)&pCsr[1];
+      pCsr->pNext = pGlobal->pCsr;
+      pGlobal->pCsr = pCsr;
+      pCsr->iCsrId = ++pGlobal->iNextId;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  return rc;
+}
+
+static int fts5StmtType(Fts5Cursor *pCsr){
+  if( pCsr->ePlan==FTS5_PLAN_SCAN ){
+    return (pCsr->bDesc) ? FTS5_STMT_SCAN_DESC : FTS5_STMT_SCAN_ASC;
+  }
+  return FTS5_STMT_LOOKUP;
+}
+
+/*
+** This function is called after the cursor passed as the only argument
+** is moved to point at a different row. It clears all cached data 
+** specific to the previous row stored by the cursor object.
+*/
+static void fts5CsrNewrow(Fts5Cursor *pCsr){
+  CsrFlagSet(pCsr, 
+      FTS5CSR_REQUIRE_CONTENT 
+    | FTS5CSR_REQUIRE_DOCSIZE 
+    | FTS5CSR_REQUIRE_INST 
+    | FTS5CSR_REQUIRE_POSLIST 
+  );
+}
+
+static void fts5FreeCursorComponents(Fts5Cursor *pCsr){
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  Fts5Auxdata *pData;
+  Fts5Auxdata *pNext;
+
+  sqlite3_free(pCsr->aInstIter);
+  sqlite3_free(pCsr->aInst);
+  if( pCsr->pStmt ){
+    int eStmt = fts5StmtType(pCsr);
+    sqlite3Fts5StorageStmtRelease(pTab->pStorage, eStmt, pCsr->pStmt);
+  }
+  if( pCsr->pSorter ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+  }
+
+  if( pCsr->ePlan!=FTS5_PLAN_SOURCE ){
+    sqlite3Fts5ExprFree(pCsr->pExpr);
+  }
+
+  for(pData=pCsr->pAuxdata; pData; pData=pNext){
+    pNext = pData->pNext;
+    if( pData->xDelete ) pData->xDelete(pData->pPtr);
+    sqlite3_free(pData);
+  }
+
+  sqlite3_finalize(pCsr->pRankArgStmt);
+  sqlite3_free(pCsr->apRankArg);
+
+  if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
+    sqlite3_free(pCsr->zRank);
+    sqlite3_free(pCsr->zRankArgs);
+  }
+
+  memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan - (u8*)pCsr));
+}
+
+
+/*
+** Close the cursor.  For additional information see the documentation
+** on the xClose method of the virtual table interface.
+*/
+static int fts5CloseMethod(sqlite3_vtab_cursor *pCursor){
+  if( pCursor ){
+    Fts5Table *pTab = (Fts5Table*)(pCursor->pVtab);
+    Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+    Fts5Cursor **pp;
+
+    fts5FreeCursorComponents(pCsr);
+    /* Remove the cursor from the Fts5Global.pCsr list */
+    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
+    *pp = pCsr->pNext;
+
+    sqlite3_free(pCsr);
+  }
+  return SQLITE_OK;
+}
+
+static int fts5SorterNext(Fts5Cursor *pCsr){
+  Fts5Sorter *pSorter = pCsr->pSorter;
+  int rc;
+
+  rc = sqlite3_step(pSorter->pStmt);
+  if( rc==SQLITE_DONE ){
+    rc = SQLITE_OK;
+    CsrFlagSet(pCsr, FTS5CSR_EOF);
+  }else if( rc==SQLITE_ROW ){
+    const u8 *a;
+    const u8 *aBlob;
+    int nBlob;
+    int i;
+    int iOff = 0;
+    rc = SQLITE_OK;
+
+    pSorter->iRowid = sqlite3_column_int64(pSorter->pStmt, 0);
+    nBlob = sqlite3_column_bytes(pSorter->pStmt, 1);
+    aBlob = a = sqlite3_column_blob(pSorter->pStmt, 1);
+
+    /* nBlob==0 in detail=none mode. */
+    if( nBlob>0 ){
+      for(i=0; i<(pSorter->nIdx-1); i++){
+        int iVal;
+        a += fts5GetVarint32(a, iVal);
+        iOff += iVal;
+        pSorter->aIdx[i] = iOff;
+      }
+      pSorter->aIdx[i] = &aBlob[nBlob] - a;
+      pSorter->aPoslist = a;
+    }
+
+    fts5CsrNewrow(pCsr);
+  }
+
+  return rc;
+}
+
+
+/*
+** Set the FTS5CSR_REQUIRE_RESEEK flag on all FTS5_PLAN_MATCH cursors 
+** open on table pTab.
+*/
+static void fts5TripCursors(Fts5Table *pTab){
+  Fts5Cursor *pCsr;
+  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->ePlan==FTS5_PLAN_MATCH
+     && pCsr->base.pVtab==(sqlite3_vtab*)pTab 
+    ){
+      CsrFlagSet(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    }
+  }
+}
+
+/*
+** If the REQUIRE_RESEEK flag is set on the cursor passed as the first
+** argument, close and reopen all Fts5IndexIter iterators that the cursor 
+** is using. Then attempt to move the cursor to a rowid equal to or laster
+** (in the cursors sort order - ASC or DESC) than the current rowid. 
+**
+** If the new rowid is not equal to the old, set output parameter *pbSkip
+** to 1 before returning. Otherwise, leave it unchanged.
+**
+** Return SQLITE_OK if successful or if no reseek was required, or an 
+** error code if an error occurred.
+*/
+static int fts5CursorReseek(Fts5Cursor *pCsr, int *pbSkip){
+  int rc = SQLITE_OK;
+  assert( *pbSkip==0 );
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_RESEEK) ){
+    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+    int bDesc = pCsr->bDesc;
+    i64 iRowid = sqlite3Fts5ExprRowid(pCsr->pExpr);
+
+    rc = sqlite3Fts5ExprFirst(pCsr->pExpr, pTab->pIndex, iRowid, bDesc);
+    if( rc==SQLITE_OK &&  iRowid!=sqlite3Fts5ExprRowid(pCsr->pExpr) ){
+      *pbSkip = 1;
+    }
+
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_RESEEK);
+    fts5CsrNewrow(pCsr);
+    if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
+      CsrFlagSet(pCsr, FTS5CSR_EOF);
+      *pbSkip = 1;
+    }
+  }
+  return rc;
+}
+
+
+/*
+** Advance the cursor to the next row in the table that matches the 
+** search criteria.
+**
+** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
+** even if we reach end-of-file.  The fts5EofMethod() will be called
+** subsequently to determine whether or not an EOF was hit.
+*/
+static int fts5NextMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc;
+
+  assert( (pCsr->ePlan<3)==
+          (pCsr->ePlan==FTS5_PLAN_MATCH || pCsr->ePlan==FTS5_PLAN_SOURCE) 
+  );
+  assert( !CsrFlagTest(pCsr, FTS5CSR_EOF) );
+
+  if( pCsr->ePlan<3 ){
+    int bSkip = 0;
+    if( (rc = fts5CursorReseek(pCsr, &bSkip)) || bSkip ) return rc;
+    rc = sqlite3Fts5ExprNext(pCsr->pExpr, pCsr->iLastRowid);
+    CsrFlagSet(pCsr, sqlite3Fts5ExprEof(pCsr->pExpr));
+    fts5CsrNewrow(pCsr);
+  }else{
+    switch( pCsr->ePlan ){
+      case FTS5_PLAN_SPECIAL: {
+        CsrFlagSet(pCsr, FTS5CSR_EOF);
+        rc = SQLITE_OK;
+        break;
+      }
+  
+      case FTS5_PLAN_SORTED_MATCH: {
+        rc = fts5SorterNext(pCsr);
+        break;
+      }
+  
+      default:
+        rc = sqlite3_step(pCsr->pStmt);
+        if( rc!=SQLITE_ROW ){
+          CsrFlagSet(pCsr, FTS5CSR_EOF);
+          rc = sqlite3_reset(pCsr->pStmt);
+        }else{
+          rc = SQLITE_OK;
+        }
+        break;
+    }
+  }
+  
+  return rc;
+}
+
+
+static int fts5PrepareStatement(
+  sqlite3_stmt **ppStmt,
+  Fts5Config *pConfig, 
+  const char *zFmt,
+  ...
+){
+  sqlite3_stmt *pRet = 0;
+  int rc;
+  char *zSql;
+  va_list ap;
+
+  va_start(ap, zFmt);
+  zSql = sqlite3_vmprintf(zFmt, ap);
+  if( zSql==0 ){
+    rc = SQLITE_NOMEM; 
+  }else{
+    rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &pRet, 0);
+    if( rc!=SQLITE_OK ){
+      *pConfig->pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(pConfig->db));
+    }
+    sqlite3_free(zSql);
+  }
+
+  va_end(ap);
+  *ppStmt = pRet;
+  return rc;
+} 
+
+static int fts5CursorFirstSorted(Fts5Table *pTab, Fts5Cursor *pCsr, int bDesc){
+  Fts5Config *pConfig = pTab->pConfig;
+  Fts5Sorter *pSorter;
+  int nPhrase;
+  int nByte;
+  int rc;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+  
+  nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  nByte = sizeof(Fts5Sorter) + sizeof(int) * (nPhrase-1);
+  pSorter = (Fts5Sorter*)sqlite3_malloc(nByte);
+  if( pSorter==0 ) return SQLITE_NOMEM;
+  memset(pSorter, 0, nByte);
+  pSorter->nIdx = nPhrase;
+
+  /* TODO: It would be better to have some system for reusing statement
+  ** handles here, rather than preparing a new one for each query. But that
+  ** is not possible as SQLite reference counts the virtual table objects.
+  ** And since the statement required here reads from this very virtual 
+  ** table, saving it creates a circular reference.
+  **
+  ** If SQLite a built-in statement cache, this wouldn't be a problem. */
+  rc = fts5PrepareStatement(&pSorter->pStmt, pConfig,
+      "SELECT rowid, rank FROM %Q.%Q ORDER BY %s(%s%s%s) %s",
+      pConfig->zDb, pConfig->zName, zRank, pConfig->zName,
+      (zRankArgs ? ", " : ""),
+      (zRankArgs ? zRankArgs : ""),
+      bDesc ? "DESC" : "ASC"
+  );
+
+  pCsr->pSorter = pSorter;
+  if( rc==SQLITE_OK ){
+    assert( pTab->pSortCsr==0 );
+    pTab->pSortCsr = pCsr;
+    rc = fts5SorterNext(pCsr);
+    pTab->pSortCsr = 0;
+  }
+
+  if( rc!=SQLITE_OK ){
+    sqlite3_finalize(pSorter->pStmt);
+    sqlite3_free(pSorter);
+    pCsr->pSorter = 0;
+  }
+
+  return rc;
+}
+
+static int fts5CursorFirst(Fts5Table *pTab, Fts5Cursor *pCsr, int bDesc){
+  int rc;
+  Fts5Expr *pExpr = pCsr->pExpr;
+  rc = sqlite3Fts5ExprFirst(pExpr, pTab->pIndex, pCsr->iFirstRowid, bDesc);
+  if( sqlite3Fts5ExprEof(pExpr) ){
+    CsrFlagSet(pCsr, FTS5CSR_EOF);
+  }
+  fts5CsrNewrow(pCsr);
+  return rc;
+}
+
+/*
+** Process a "special" query. A special query is identified as one with a
+** MATCH expression that begins with a '*' character. The remainder of
+** the text passed to the MATCH operator are used as  the special query
+** parameters.
+*/
+static int fts5SpecialMatch(
+  Fts5Table *pTab, 
+  Fts5Cursor *pCsr, 
+  const char *zQuery
+){
+  int rc = SQLITE_OK;             /* Return code */
+  const char *z = zQuery;         /* Special query text */
+  int n;                          /* Number of bytes in text at z */
+
+  while( z[0]==' ' ) z++;
+  for(n=0; z[n] && z[n]!=' '; n++);
+
+  assert( pTab->base.zErrMsg==0 );
+  pCsr->ePlan = FTS5_PLAN_SPECIAL;
+
+  if( 0==sqlite3_strnicmp("reads", z, n) ){
+    pCsr->iSpecial = sqlite3Fts5IndexReads(pTab->pIndex);
+  }
+  else if( 0==sqlite3_strnicmp("id", z, n) ){
+    pCsr->iSpecial = pCsr->iCsrId;
+  }
+  else{
+    /* An unrecognized directive. Return an error message. */
+    pTab->base.zErrMsg = sqlite3_mprintf("unknown special query: %.*s", n, z);
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+/*
+** Search for an auxiliary function named zName that can be used with table
+** pTab. If one is found, return a pointer to the corresponding Fts5Auxiliary
+** structure. Otherwise, if no such function exists, return NULL.
+*/
+static Fts5Auxiliary *fts5FindAuxiliary(Fts5Table *pTab, const char *zName){
+  Fts5Auxiliary *pAux;
+
+  for(pAux=pTab->pGlobal->pAux; pAux; pAux=pAux->pNext){
+    if( sqlite3_stricmp(zName, pAux->zFunc)==0 ) return pAux;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+
+static int fts5FindRankFunction(Fts5Cursor *pCsr){
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->pConfig;
+  int rc = SQLITE_OK;
+  Fts5Auxiliary *pAux = 0;
+  const char *zRank = pCsr->zRank;
+  const char *zRankArgs = pCsr->zRankArgs;
+
+  if( zRankArgs ){
+    char *zSql = sqlite3Fts5Mprintf(&rc, "SELECT %s", zRankArgs);
+    if( zSql ){
+      sqlite3_stmt *pStmt = 0;
+      rc = sqlite3_prepare_v2(pConfig->db, zSql, -1, &pStmt, 0);
+      sqlite3_free(zSql);
+      assert( rc==SQLITE_OK || pCsr->pRankArgStmt==0 );
+      if( rc==SQLITE_OK ){
+        if( SQLITE_ROW==sqlite3_step(pStmt) ){
+          int nByte;
+          pCsr->nRankArg = sqlite3_column_count(pStmt);
+          nByte = sizeof(sqlite3_value*)*pCsr->nRankArg;
+          pCsr->apRankArg = (sqlite3_value**)sqlite3Fts5MallocZero(&rc, nByte);
+          if( rc==SQLITE_OK ){
+            int i;
+            for(i=0; i<pCsr->nRankArg; i++){
+              pCsr->apRankArg[i] = sqlite3_column_value(pStmt, i);
+            }
+          }
+          pCsr->pRankArgStmt = pStmt;
+        }else{
+          rc = sqlite3_finalize(pStmt);
+          assert( rc!=SQLITE_OK );
+        }
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK ){
+    pAux = fts5FindAuxiliary(pTab, zRank);
+    if( pAux==0 ){
+      assert( pTab->base.zErrMsg==0 );
+      pTab->base.zErrMsg = sqlite3_mprintf("no such function: %s", zRank);
+      rc = SQLITE_ERROR;
+    }
+  }
+
+  pCsr->pRank = pAux;
+  return rc;
+}
+
+
+static int fts5CursorParseRank(
+  Fts5Config *pConfig,
+  Fts5Cursor *pCsr, 
+  sqlite3_value *pRank
+){
+  int rc = SQLITE_OK;
+  if( pRank ){
+    const char *z = (const char*)sqlite3_value_text(pRank);
+    char *zRank = 0;
+    char *zRankArgs = 0;
+
+    if( z==0 ){
+      if( sqlite3_value_type(pRank)==SQLITE_NULL ) rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5ConfigParseRank(z, &zRank, &zRankArgs);
+    }
+    if( rc==SQLITE_OK ){
+      pCsr->zRank = zRank;
+      pCsr->zRankArgs = zRankArgs;
+      CsrFlagSet(pCsr, FTS5CSR_FREE_ZRANK);
+    }else if( rc==SQLITE_ERROR ){
+      pCsr->base.pVtab->zErrMsg = sqlite3_mprintf(
+          "parse error in rank function: %s", z
+      );
+    }
+  }else{
+    if( pConfig->zRank ){
+      pCsr->zRank = (char*)pConfig->zRank;
+      pCsr->zRankArgs = (char*)pConfig->zRankArgs;
+    }else{
+      pCsr->zRank = (char*)FTS5_DEFAULT_RANK;
+      pCsr->zRankArgs = 0;
+    }
+  }
+  return rc;
+}
+
+static i64 fts5GetRowidLimit(sqlite3_value *pVal, i64 iDefault){
+  if( pVal ){
+    int eType = sqlite3_value_numeric_type(pVal);
+    if( eType==SQLITE_INTEGER ){
+      return sqlite3_value_int64(pVal);
+    }
+  }
+  return iDefault;
+}
+
+/*
+** This is the xFilter interface for the virtual table.  See
+** the virtual table xFilter method documentation for additional
+** information.
+** 
+** There are three possible query strategies:
+**
+**   1. Full-text search using a MATCH operator.
+**   2. A by-rowid lookup.
+**   3. A full-table scan.
+*/
+static int fts5FilterMethod(
+  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
+  int idxNum,                     /* Strategy index */
+  const char *zUnused,            /* Unused */
+  int nVal,                       /* Number of elements in apVal */
+  sqlite3_value **apVal           /* Arguments for the indexing scheme */
+){
+  Fts5Table *pTab = (Fts5Table*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;             /* Error code */
+  int iVal = 0;                   /* Counter for apVal[] */
+  int bDesc;                      /* True if ORDER BY [rank|rowid] DESC */
+  int bOrderByRank;               /* True if ORDER BY rank */
+  sqlite3_value *pMatch = 0;      /* <tbl> MATCH ? expression (or NULL) */
+  sqlite3_value *pRank = 0;       /* rank MATCH ? expression (or NULL) */
+  sqlite3_value *pRowidEq = 0;    /* rowid = ? expression (or NULL) */
+  sqlite3_value *pRowidLe = 0;    /* rowid <= ? expression (or NULL) */
+  sqlite3_value *pRowidGe = 0;    /* rowid >= ? expression (or NULL) */
+  char **pzErrmsg = pConfig->pzErrmsg;
+
+  UNUSED_PARAM(zUnused);
+  UNUSED_PARAM(nVal);
+
+  if( pCsr->ePlan ){
+    fts5FreeCursorComponents(pCsr);
+    memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan-(u8*)pCsr));
+  }
+
+  assert( pCsr->pStmt==0 );
+  assert( pCsr->pExpr==0 );
+  assert( pCsr->csrflags==0 );
+  assert( pCsr->pRank==0 );
+  assert( pCsr->zRank==0 );
+  assert( pCsr->zRankArgs==0 );
+
+  assert( pzErrmsg==0 || pzErrmsg==&pTab->base.zErrMsg );
+  pConfig->pzErrmsg = &pTab->base.zErrMsg;
+
+  /* Decode the arguments passed through to this function.
+  **
+  ** Note: The following set of if(...) statements must be in the same
+  ** order as the corresponding entries in the struct at the top of
+  ** fts5BestIndexMethod().  */
+  if( BitFlagTest(idxNum, FTS5_BI_MATCH) ) pMatch = apVal[iVal++];
+  if( BitFlagTest(idxNum, FTS5_BI_RANK) ) pRank = apVal[iVal++];
+  if( BitFlagTest(idxNum, FTS5_BI_ROWID_EQ) ) pRowidEq = apVal[iVal++];
+  if( BitFlagTest(idxNum, FTS5_BI_ROWID_LE) ) pRowidLe = apVal[iVal++];
+  if( BitFlagTest(idxNum, FTS5_BI_ROWID_GE) ) pRowidGe = apVal[iVal++];
+  assert( iVal==nVal );
+  bOrderByRank = ((idxNum & FTS5_BI_ORDER_RANK) ? 1 : 0);
+  pCsr->bDesc = bDesc = ((idxNum & FTS5_BI_ORDER_DESC) ? 1 : 0);
+
+  /* Set the cursor upper and lower rowid limits. Only some strategies 
+  ** actually use them. This is ok, as the xBestIndex() method leaves the
+  ** sqlite3_index_constraint.omit flag clear for range constraints
+  ** on the rowid field.  */
+  if( pRowidEq ){
+    pRowidLe = pRowidGe = pRowidEq;
+  }
+  if( bDesc ){
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }else{
+    pCsr->iLastRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
+    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
+  }
+
+  if( pTab->pSortCsr ){
+    /* If pSortCsr is non-NULL, then this call is being made as part of 
+    ** processing for a "... MATCH <expr> ORDER BY rank" query (ePlan is
+    ** set to FTS5_PLAN_SORTED_MATCH). pSortCsr is the cursor that will
+    ** return results to the user for this query. The current cursor 
+    ** (pCursor) is used to execute the query issued by function 
+    ** fts5CursorFirstSorted() above.  */
+    assert( pRowidEq==0 && pRowidLe==0 && pRowidGe==0 && pRank==0 );
+    assert( nVal==0 && pMatch==0 && bOrderByRank==0 && bDesc==0 );
+    assert( pCsr->iLastRowid==LARGEST_INT64 );
+    assert( pCsr->iFirstRowid==SMALLEST_INT64 );
+    pCsr->ePlan = FTS5_PLAN_SOURCE;
+    pCsr->pExpr = pTab->pSortCsr->pExpr;
+    rc = fts5CursorFirst(pTab, pCsr, bDesc);
+  }else if( pMatch ){
+    const char *zExpr = (const char*)sqlite3_value_text(apVal[0]);
+    if( zExpr==0 ) zExpr = "";
+
+    rc = fts5CursorParseRank(pConfig, pCsr, pRank);
+    if( rc==SQLITE_OK ){
+      if( zExpr[0]=='*' ){
+        /* The user has issued a query of the form "MATCH '*...'". This
+        ** indicates that the MATCH expression is not a full text query,
+        ** but a request for an internal parameter.  */
+        rc = fts5SpecialMatch(pTab, pCsr, &zExpr[1]);
+      }else{
+        char **pzErr = &pTab->base.zErrMsg;
+        rc = sqlite3Fts5ExprNew(pConfig, zExpr, &pCsr->pExpr, pzErr);
+        if( rc==SQLITE_OK ){
+          if( bOrderByRank ){
+            pCsr->ePlan = FTS5_PLAN_SORTED_MATCH;
+            rc = fts5CursorFirstSorted(pTab, pCsr, bDesc);
+          }else{
+            pCsr->ePlan = FTS5_PLAN_MATCH;
+            rc = fts5CursorFirst(pTab, pCsr, bDesc);
+          }
+        }
+      }
+    }
+  }else if( pConfig->zContent==0 ){
+    *pConfig->pzErrmsg = sqlite3_mprintf(
+        "%s: table does not support scanning", pConfig->zName
+    );
+    rc = SQLITE_ERROR;
+  }else{
+    /* This is either a full-table scan (ePlan==FTS5_PLAN_SCAN) or a lookup
+    ** by rowid (ePlan==FTS5_PLAN_ROWID).  */
+    pCsr->ePlan = (pRowidEq ? FTS5_PLAN_ROWID : FTS5_PLAN_SCAN);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, fts5StmtType(pCsr), &pCsr->pStmt, &pTab->base.zErrMsg
+    );
+    if( rc==SQLITE_OK ){
+      if( pCsr->ePlan==FTS5_PLAN_ROWID ){
+        sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);
+      }else{
+        sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iFirstRowid);
+        sqlite3_bind_int64(pCsr->pStmt, 2, pCsr->iLastRowid);
+      }
+      rc = fts5NextMethod(pCursor);
+    }
+  }
+
+  pConfig->pzErrmsg = pzErrmsg;
+  return rc;
+}
+
+/* 
+** This is the xEof method of the virtual table. SQLite calls this 
+** routine to find out if it has reached the end of a result set.
+*/
+static int fts5EofMethod(sqlite3_vtab_cursor *pCursor){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  return (CsrFlagTest(pCsr, FTS5CSR_EOF) ? 1 : 0);
+}
+
+/*
+** Return the rowid that the cursor currently points to.
+*/
+static i64 fts5CursorRowid(Fts5Cursor *pCsr){
+  assert( pCsr->ePlan==FTS5_PLAN_MATCH 
+       || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH 
+       || pCsr->ePlan==FTS5_PLAN_SOURCE 
+  );
+  if( pCsr->pSorter ){
+    return pCsr->pSorter->iRowid;
+  }else{
+    return sqlite3Fts5ExprRowid(pCsr->pExpr);
+  }
+}
+
+/* 
+** This is the xRowid method. The SQLite core calls this routine to
+** retrieve the rowid for the current row of the result set. fts5
+** exposes %_content.rowid as the rowid for the virtual table. The
+** rowid should be written to *pRowid.
+*/
+static int fts5RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int ePlan = pCsr->ePlan;
+  
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+  switch( ePlan ){
+    case FTS5_PLAN_SPECIAL:
+      *pRowid = 0;
+      break;
+
+    case FTS5_PLAN_SOURCE:
+    case FTS5_PLAN_MATCH:
+    case FTS5_PLAN_SORTED_MATCH:
+      *pRowid = fts5CursorRowid(pCsr);
+      break;
+
+    default:
+      *pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
+      break;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** If the cursor requires seeking (bSeekRequired flag is set), seek it.
+** Return SQLITE_OK if no error occurs, or an SQLite error code otherwise.
+**
+** If argument bErrormsg is true and an error occurs, an error message may
+** be left in sqlite3_vtab.zErrMsg.
+*/
+static int fts5SeekCursor(Fts5Cursor *pCsr, int bErrormsg){
+  int rc = SQLITE_OK;
+
+  /* If the cursor does not yet have a statement handle, obtain one now. */ 
+  if( pCsr->pStmt==0 ){
+    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+    int eStmt = fts5StmtType(pCsr);
+    rc = sqlite3Fts5StorageStmt(
+        pTab->pStorage, eStmt, &pCsr->pStmt, (bErrormsg?&pTab->base.zErrMsg:0)
+    );
+    assert( rc!=SQLITE_OK || pTab->base.zErrMsg==0 );
+    assert( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) );
+  }
+
+  if( rc==SQLITE_OK && CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) ){
+    assert( pCsr->pExpr );
+    sqlite3_reset(pCsr->pStmt);
+    sqlite3_bind_int64(pCsr->pStmt, 1, fts5CursorRowid(pCsr));
+    rc = sqlite3_step(pCsr->pStmt);
+    if( rc==SQLITE_ROW ){
+      rc = SQLITE_OK;
+      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);
+    }else{
+      rc = sqlite3_reset(pCsr->pStmt);
+      if( rc==SQLITE_OK ){
+        rc = FTS5_CORRUPT;
+      }
+    }
+  }
+  return rc;
+}
+
+static void fts5SetVtabError(Fts5Table *p, const char *zFormat, ...){
+  va_list ap;                     /* ... printf arguments */
+  va_start(ap, zFormat);
+  assert( p->base.zErrMsg==0 );
+  p->base.zErrMsg = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+}
+
+/*
+** This function is called to handle an FTS INSERT command. In other words,
+** an INSERT statement of the form:
+**
+**     INSERT INTO fts(fts) VALUES($pCmd)
+**     INSERT INTO fts(fts, rank) VALUES($pCmd, $pVal)
+**
+** Argument pVal is the value assigned to column "fts" by the INSERT 
+** statement. This function returns SQLITE_OK if successful, or an SQLite
+** error code if an error occurs.
+**
+** The commands implemented by this function are documented in the "Special
+** INSERT Directives" section of the documentation. It should be updated if
+** more commands are added to this function.
+*/
+static int fts5SpecialInsert(
+  Fts5Table *pTab,                /* Fts5 table object */
+  const char *zCmd,               /* Text inserted into table-name column */
+  sqlite3_value *pVal             /* Value inserted into rank column */
+){
+  Fts5Config *pConfig = pTab->pConfig;
+  int rc = SQLITE_OK;
+  int bError = 0;
+
+  if( 0==sqlite3_stricmp("delete-all", zCmd) ){
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      fts5SetVtabError(pTab, 
+          "'delete-all' may only be used with a "
+          "contentless or external content fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageDeleteAll(pTab->pStorage);
+    }
+  }else if( 0==sqlite3_stricmp("rebuild", zCmd) ){
+    if( pConfig->eContent==FTS5_CONTENT_NONE ){
+      fts5SetVtabError(pTab, 
+          "'rebuild' may not be used with a contentless fts5 table"
+      );
+      rc = SQLITE_ERROR;
+    }else{
+      rc = sqlite3Fts5StorageRebuild(pTab->pStorage);
+    }
+  }else if( 0==sqlite3_stricmp("optimize", zCmd) ){
+    rc = sqlite3Fts5StorageOptimize(pTab->pStorage);
+  }else if( 0==sqlite3_stricmp("merge", zCmd) ){
+    int nMerge = sqlite3_value_int(pVal);
+    rc = sqlite3Fts5StorageMerge(pTab->pStorage, nMerge);
+  }else if( 0==sqlite3_stricmp("integrity-check", zCmd) ){
+    rc = sqlite3Fts5StorageIntegrity(pTab->pStorage);
+#ifdef SQLITE_DEBUG
+  }else if( 0==sqlite3_stricmp("prefix-index", zCmd) ){
+    pConfig->bPrefixIndex = sqlite3_value_int(pVal);
+#endif
+  }else{
+    rc = sqlite3Fts5IndexLoadConfig(pTab->pIndex);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3Fts5ConfigSetValue(pTab->pConfig, zCmd, pVal, &bError);
+    }
+    if( rc==SQLITE_OK ){
+      if( bError ){
+        rc = SQLITE_ERROR;
+      }else{
+        rc = sqlite3Fts5StorageConfigValue(pTab->pStorage, zCmd, pVal, 0);
+      }
+    }
+  }
+  return rc;
+}
+
+static int fts5SpecialDelete(
+  Fts5Table *pTab, 
+  sqlite3_value **apVal
+){
+  int rc = SQLITE_OK;
+  int eType1 = sqlite3_value_type(apVal[1]);
+  if( eType1==SQLITE_INTEGER ){
+    sqlite3_int64 iDel = sqlite3_value_int64(apVal[1]);
+    rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, &apVal[2]);
+  }
+  return rc;
+}
+
+static void fts5StorageInsert(
+  int *pRc, 
+  Fts5Table *pTab, 
+  sqlite3_value **apVal, 
+  i64 *piRowid
+){
+  int rc = *pRc;
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageContentInsert(pTab->pStorage, apVal, piRowid);
+  }
+  if( rc==SQLITE_OK ){
+    rc = sqlite3Fts5StorageIndexInsert(pTab->pStorage, apVal, *piRowid);
+  }
+  *pRc = rc;
+}
+
+/* 
+** This function is the implementation of the xUpdate callback used by 
+** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
+** inserted, updated or deleted.
+**
+** A delete specifies a single argument - the rowid of the row to remove.
+** 
+** Update and insert operations pass:
+**
+**   1. The "old" rowid, or NULL.
+**   2. The "new" rowid.
+**   3. Values for each of the nCol matchable columns.
+**   4. Values for the two hidden columns (<tablename> and "rank").
+*/
+static int fts5UpdateMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Size of argument array */
+  sqlite3_value **apVal,          /* Array of arguments */
+  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
+){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  Fts5Config *pConfig = pTab->pConfig;
+  int eType0;                     /* value_type() of apVal[0] */
+  int rc = SQLITE_OK;             /* Return code */
+
+  /* A transaction must be open when this is called. */
+  assert( pTab->ts.eState==1 );
+
+  assert( pVtab->zErrMsg==0 );
+  assert( nArg==1 || nArg==(2+pConfig->nCol+2) );
+  assert( nArg==1 
+      || sqlite3_value_type(apVal[1])==SQLITE_INTEGER 
+      || sqlite3_value_type(apVal[1])==SQLITE_NULL 
+  );
+  assert( pTab->pConfig->pzErrmsg==0 );
+  pTab->pConfig->pzErrmsg = &pTab->base.zErrMsg;
+
+  /* Put any active cursors into REQUIRE_SEEK state. */
+  fts5TripCursors(pTab);
+
+  eType0 = sqlite3_value_type(apVal[0]);
+  if( eType0==SQLITE_NULL 
+   && sqlite3_value_type(apVal[2+pConfig->nCol])!=SQLITE_NULL 
+  ){
+    /* A "special" INSERT op. These are handled separately. */
+    const char *z = (const char*)sqlite3_value_text(apVal[2+pConfig->nCol]);
+    if( pConfig->eContent!=FTS5_CONTENT_NORMAL 
+      && 0==sqlite3_stricmp("delete", z) 
+    ){
+      rc = fts5SpecialDelete(pTab, apVal);
+    }else{
+      rc = fts5SpecialInsert(pTab, z, apVal[2 + pConfig->nCol + 1]);
+    }
+  }else{
+    /* A regular INSERT, UPDATE or DELETE statement. The trick here is that
+    ** any conflict on the rowid value must be detected before any 
+    ** modifications are made to the database file. There are 4 cases:
+    **
+    **   1) DELETE
+    **   2) UPDATE (rowid not modified)
+    **   3) UPDATE (rowid modified)
+    **   4) INSERT
+    **
+    ** Cases 3 and 4 may violate the rowid constraint.
+    */
+    int eConflict = SQLITE_ABORT;
+    if( pConfig->eContent==FTS5_CONTENT_NORMAL ){
+      eConflict = sqlite3_vtab_on_conflict(pConfig->db);
+    }
+
+    assert( eType0==SQLITE_INTEGER || eType0==SQLITE_NULL );
+    assert( nArg!=1 || eType0==SQLITE_INTEGER );
+
+    /* Filter out attempts to run UPDATE or DELETE on contentless tables.
+    ** This is not suported.  */
+    if( eType0==SQLITE_INTEGER && fts5IsContentless(pTab) ){
+      pTab->base.zErrMsg = sqlite3_mprintf(
+          "cannot %s contentless fts5 table: %s", 
+          (nArg>1 ? "UPDATE" : "DELETE from"), pConfig->zName
+      );
+      rc = SQLITE_ERROR;
+    }
+
+    /* DELETE */
+    else if( nArg==1 ){
+      i64 iDel = sqlite3_value_int64(apVal[0]);  /* Rowid to delete */
+      rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, 0);
+    }
+
+    /* INSERT */
+    else if( eType0!=SQLITE_INTEGER ){     
+      /* If this is a REPLACE, first remove the current entry (if any) */
+      if( eConflict==SQLITE_REPLACE 
+       && sqlite3_value_type(apVal[1])==SQLITE_INTEGER 
+      ){
+        i64 iNew = sqlite3_value_int64(apVal[1]);  /* Rowid to delete */
+        rc = sqlite3Fts5StorageDelete(pTab->pStorage, iNew, 0);
+      }
+      fts5StorageInsert(&rc, pTab, apVal, pRowid);
+    }
+
+    /* UPDATE */
+    else{
+      i64 iOld = sqlite3_value_int64(apVal[0]);  /* Old rowid */
+      i64 iNew = sqlite3_value_int64(apVal[1]);  /* New rowid */
+      if( iOld!=iNew ){
+        if( eConflict==SQLITE_REPLACE ){
+          rc = sqlite3Fts5StorageDelete(pTab->pStorage, iOld, 0);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5StorageDelete(pTab->pStorage, iNew, 0);
+          }
+          fts5StorageInsert(&rc, pTab, apVal, pRowid);
+        }else{
+          rc = sqlite3Fts5StorageContentInsert(pTab->pStorage, apVal, pRowid);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5StorageDelete(pTab->pStorage, iOld, 0);
+          }
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5StorageIndexInsert(pTab->pStorage, apVal, *pRowid);
+          }
+        }
+      }else{
+        rc = sqlite3Fts5StorageDelete(pTab->pStorage, iOld, 0);
+        fts5StorageInsert(&rc, pTab, apVal, pRowid);
+      }
+    }
+  }
+
+  pTab->pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xSync() method. 
+*/
+static int fts5SyncMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_SYNC, 0);
+  pTab->pConfig->pzErrmsg = &pTab->base.zErrMsg;
+  fts5TripCursors(pTab);
+  rc = sqlite3Fts5StorageSync(pTab->pStorage, 1);
+  pTab->pConfig->pzErrmsg = 0;
+  return rc;
+}
+
+/*
+** Implementation of xBegin() method. 
+*/
+static int fts5BeginMethod(sqlite3_vtab *pVtab){
+  fts5CheckTransactionState((Fts5Table*)pVtab, FTS5_BEGIN, 0);
+  fts5NewTransaction((Fts5Table*)pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xCommit() method. This is a no-op. The contents of
+** the pending-terms hash-table have already been flushed into the database
+** by fts5SyncMethod().
+*/
+static int fts5CommitMethod(sqlite3_vtab *pVtab){
+  UNUSED_PARAM(pVtab);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState((Fts5Table*)pVtab, FTS5_COMMIT, 0);
+  return SQLITE_OK;
+}
+
+/*
+** Implementation of xRollback(). Discard the contents of the pending-terms
+** hash-table. Any changes made to the database are reverted by SQLite.
+*/
+static int fts5RollbackMethod(sqlite3_vtab *pVtab){
+  int rc;
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACK, 0);
+  rc = sqlite3Fts5StorageRollback(pTab->pStorage);
+  return rc;
+}
+
+static int fts5CsrPoslist(Fts5Cursor*, int, const u8**, int*);
+
+static void *fts5ApiUserData(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return pCsr->pAux->pUserData;
+}
+
+static int fts5ApiColumnCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return ((Fts5Table*)(pCsr->base.pVtab))->pConfig->nCol;
+}
+
+static int fts5ApiColumnTotalSize(
+  Fts5Context *pCtx, 
+  int iCol, 
+  sqlite3_int64 *pnToken
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageSize(pTab->pStorage, iCol, pnToken);
+}
+
+static int fts5ApiRowCount(Fts5Context *pCtx, i64 *pnRow){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  return sqlite3Fts5StorageRowCount(pTab->pStorage, pnRow);
+}
+
+static int fts5ApiTokenize(
+  Fts5Context *pCtx, 
+  const char *pText, int nText, 
+  void *pUserData,
+  int (*xToken)(void*, int, const char*, int, int, int)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  return sqlite3Fts5Tokenize(
+      pTab->pConfig, FTS5_TOKENIZE_AUX, pText, nText, pUserData, xToken
+  );
+}
+
+static int fts5ApiPhraseCount(Fts5Context *pCtx){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+}
+
+static int fts5ApiPhraseSize(Fts5Context *pCtx, int iPhrase){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  return sqlite3Fts5ExprPhraseSize(pCsr->pExpr, iPhrase);
+}
+
+static int fts5ApiColumnText(
+  Fts5Context *pCtx, 
+  int iCol, 
+  const char **pz, 
+  int *pn
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  if( fts5IsContentless((Fts5Table*)(pCsr->base.pVtab)) ){
+    *pz = 0;
+    *pn = 0;
+  }else{
+    rc = fts5SeekCursor(pCsr, 0);
+    if( rc==SQLITE_OK ){
+      *pz = (const char*)sqlite3_column_text(pCsr->pStmt, iCol+1);
+      *pn = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
+    }
+  }
+  return rc;
+}
+
+static int fts5CsrPoslist(
+  Fts5Cursor *pCsr, 
+  int iPhrase, 
+  const u8 **pa,
+  int *pn
+){
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+  int rc = SQLITE_OK;
+  int bLive = (pCsr->pSorter==0);
+
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_POSLIST) ){
+
+    if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
+      Fts5PoslistPopulator *aPopulator;
+      int i;
+      aPopulator = sqlite3Fts5ExprClearPoslists(pCsr->pExpr, bLive);
+      if( aPopulator==0 ) rc = SQLITE_NOMEM;
+      for(i=0; i<pConfig->nCol && rc==SQLITE_OK; i++){
+        int n; const char *z;
+        rc = fts5ApiColumnText((Fts5Context*)pCsr, i, &z, &n);
+        if( rc==SQLITE_OK ){
+          rc = sqlite3Fts5ExprPopulatePoslists(
+              pConfig, pCsr->pExpr, aPopulator, i, z, n
+          );
+        }
+      }
+      sqlite3_free(aPopulator);
+
+      if( pCsr->pSorter ){
+        sqlite3Fts5ExprCheckPoslists(pCsr->pExpr, pCsr->pSorter->iRowid);
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_POSLIST);
+  }
+
+  if( pCsr->pSorter && pConfig->eDetail==FTS5_DETAIL_FULL ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+    *pn = pSorter->aIdx[iPhrase] - i1;
+    *pa = &pSorter->aPoslist[i1];
+  }else{
+    *pn = sqlite3Fts5ExprPoslist(pCsr->pExpr, iPhrase, pa);
+  }
+
+  return rc;
+}
+
+/*
+** Ensure that the Fts5Cursor.nInstCount and aInst[] variables are populated
+** correctly for the current view. Return SQLITE_OK if successful, or an
+** SQLite error code otherwise.
+*/
+static int fts5CacheInstArray(Fts5Cursor *pCsr){
+  int rc = SQLITE_OK;
+  Fts5PoslistReader *aIter;       /* One iterator for each phrase */
+  int nIter;                      /* Number of iterators/phrases */
+  
+  nIter = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  if( pCsr->aInstIter==0 ){
+    int nByte = sizeof(Fts5PoslistReader) * nIter;
+    pCsr->aInstIter = (Fts5PoslistReader*)sqlite3Fts5MallocZero(&rc, nByte);
+  }
+  aIter = pCsr->aInstIter;
+
+  if( aIter ){
+    int nInst = 0;                /* Number instances seen so far */
+    int i;
+
+    /* Initialize all iterators */
+    for(i=0; i<nIter && rc==SQLITE_OK; i++){
+      const u8 *a;
+      int n; 
+      rc = fts5CsrPoslist(pCsr, i, &a, &n);
+      if( rc==SQLITE_OK ){
+        sqlite3Fts5PoslistReaderInit(a, n, &aIter[i]);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      while( 1 ){
+        int *aInst;
+        int iBest = -1;
+        for(i=0; i<nIter; i++){
+          if( (aIter[i].bEof==0) 
+              && (iBest<0 || aIter[i].iPos<aIter[iBest].iPos) 
+            ){
+            iBest = i;
+          }
+        }
+        if( iBest<0 ) break;
+
+        nInst++;
+        if( nInst>=pCsr->nInstAlloc ){
+          pCsr->nInstAlloc = pCsr->nInstAlloc ? pCsr->nInstAlloc*2 : 32;
+          aInst = (int*)sqlite3_realloc(
+              pCsr->aInst, pCsr->nInstAlloc*sizeof(int)*3
+              );
+          if( aInst ){
+            pCsr->aInst = aInst;
+          }else{
+            rc = SQLITE_NOMEM;
+            break;
+          }
+        }
+
+        aInst = &pCsr->aInst[3 * (nInst-1)];
+        aInst[0] = iBest;
+        aInst[1] = FTS5_POS2COLUMN(aIter[iBest].iPos);
+        aInst[2] = FTS5_POS2OFFSET(aIter[iBest].iPos);
+        sqlite3Fts5PoslistReaderNext(&aIter[iBest]);
+      }
+    }
+
+    pCsr->nInstCount = nInst;
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_INST);
+  }
+  return rc;
+}
+
+static int fts5ApiInstCount(Fts5Context *pCtx, int *pnInst){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0 
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr)) ){
+    *pnInst = pCsr->nInstCount;
+  }
+  return rc;
+}
+
+static int fts5ApiInst(
+  Fts5Context *pCtx, 
+  int iIdx, 
+  int *piPhrase, 
+  int *piCol, 
+  int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int rc = SQLITE_OK;
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_INST)==0 
+   || SQLITE_OK==(rc = fts5CacheInstArray(pCsr)) 
+  ){
+    if( iIdx<0 || iIdx>=pCsr->nInstCount ){
+      rc = SQLITE_RANGE;
+#if 0
+    }else if( fts5IsOffsetless((Fts5Table*)pCsr->base.pVtab) ){
+      *piPhrase = pCsr->aInst[iIdx*3];
+      *piCol = pCsr->aInst[iIdx*3 + 2];
+      *piOff = -1;
+#endif
+    }else{
+      *piPhrase = pCsr->aInst[iIdx*3];
+      *piCol = pCsr->aInst[iIdx*3 + 1];
+      *piOff = pCsr->aInst[iIdx*3 + 2];
+    }
+  }
+  return rc;
+}
+
+static sqlite3_int64 fts5ApiRowid(Fts5Context *pCtx){
+  return fts5CursorRowid((Fts5Cursor*)pCtx);
+}
+
+static int fts5ColumnSizeCb(
+  void *pContext,                 /* Pointer to int */
+  int tflags,
+  const char *pUnused,            /* Buffer containing token */
+  int nUnused,                    /* Size of token in bytes */
+  int iUnused1,                   /* Start offset of token */
+  int iUnused2                    /* End offset of token */
+){
+  int *pCnt = (int*)pContext;
+  UNUSED_PARAM2(pUnused, nUnused);
+  UNUSED_PARAM2(iUnused1, iUnused2);
+  if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
+    (*pCnt)++;
+  }
+  return SQLITE_OK;
+}
+
+static int fts5ApiColumnSize(Fts5Context *pCtx, int iCol, int *pnToken){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  Fts5Config *pConfig = pTab->pConfig;
+  int rc = SQLITE_OK;
+
+  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_DOCSIZE) ){
+    if( pConfig->bColumnsize ){
+      i64 iRowid = fts5CursorRowid(pCsr);
+      rc = sqlite3Fts5StorageDocsize(pTab->pStorage, iRowid, pCsr->aColumnSize);
+    }else if( pConfig->zContent==0 ){
+      int i;
+      for(i=0; i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          pCsr->aColumnSize[i] = -1;
+        }
+      }
+    }else{
+      int i;
+      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
+        if( pConfig->abUnindexed[i]==0 ){
+          const char *z; int n;
+          void *p = (void*)(&pCsr->aColumnSize[i]);
+          pCsr->aColumnSize[i] = 0;
+          rc = fts5ApiColumnText(pCtx, i, &z, &n);
+          if( rc==SQLITE_OK ){
+            rc = sqlite3Fts5Tokenize(
+                pConfig, FTS5_TOKENIZE_AUX, z, n, p, fts5ColumnSizeCb
+            );
+          }
+        }
+      }
+    }
+    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
+  }
+  if( iCol<0 ){
+    int i;
+    *pnToken = 0;
+    for(i=0; i<pConfig->nCol; i++){
+      *pnToken += pCsr->aColumnSize[i];
+    }
+  }else if( iCol<pConfig->nCol ){
+    *pnToken = pCsr->aColumnSize[iCol];
+  }else{
+    *pnToken = 0;
+    rc = SQLITE_RANGE;
+  }
+  return rc;
+}
+
+/*
+** Implementation of the xSetAuxdata() method.
+*/
+static int fts5ApiSetAuxdata(
+  Fts5Context *pCtx,              /* Fts5 context */
+  void *pPtr,                     /* Pointer to save as auxdata */
+  void(*xDelete)(void*)           /* Destructor for pPtr (or NULL) */
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+
+  /* Search through the cursors list of Fts5Auxdata objects for one that
+  ** corresponds to the currently executing auxiliary function.  */
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    if( pData->xDelete ){
+      pData->xDelete(pData->pPtr);
+    }
+  }else{
+    int rc = SQLITE_OK;
+    pData = (Fts5Auxdata*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Auxdata));
+    if( pData==0 ){
+      if( xDelete ) xDelete(pPtr);
+      return rc;
+    }
+    pData->pAux = pCsr->pAux;
+    pData->pNext = pCsr->pAuxdata;
+    pCsr->pAuxdata = pData;
+  }
+
+  pData->xDelete = xDelete;
+  pData->pPtr = pPtr;
+  return SQLITE_OK;
+}
+
+static void *fts5ApiGetAuxdata(Fts5Context *pCtx, int bClear){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Auxdata *pData;
+  void *pRet = 0;
+
+  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
+    if( pData->pAux==pCsr->pAux ) break;
+  }
+
+  if( pData ){
+    pRet = pData->pPtr;
+    if( bClear ){
+      pData->pPtr = 0;
+      pData->xDelete = 0;
+    }
+  }
+
+  return pRet;
+}
+
+static void fts5ApiPhraseNext(
+  Fts5Context *pUnused, 
+  Fts5PhraseIter *pIter, 
+  int *piCol, int *piOff
+){
+  UNUSED_PARAM(pUnused);
+  if( pIter->a>=pIter->b ){
+    *piCol = -1;
+    *piOff = -1;
+  }else{
+    int iVal;
+    pIter->a += fts5GetVarint32(pIter->a, iVal);
+    if( iVal==1 ){
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+      *piCol = iVal;
+      *piOff = 0;
+      pIter->a += fts5GetVarint32(pIter->a, iVal);
+    }
+    *piOff += (iVal-2);
+  }
+}
+
+static int fts5ApiPhraseFirst(
+  Fts5Context *pCtx, 
+  int iPhrase, 
+  Fts5PhraseIter *pIter, 
+  int *piCol, int *piOff
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  int n;
+  int rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+  if( rc==SQLITE_OK ){
+    pIter->b = &pIter->a[n];
+    *piCol = 0;
+    *piOff = 0;
+    fts5ApiPhraseNext(pCtx, pIter, piCol, piOff);
+  }
+  return rc;
+}
+
+static void fts5ApiPhraseNextColumn(
+  Fts5Context *pCtx, 
+  Fts5PhraseIter *pIter, 
+  int *piCol
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    if( pIter->a>=pIter->b ){
+      *piCol = -1;
+    }else{
+      int iIncr;
+      pIter->a += fts5GetVarint32(&pIter->a[0], iIncr);
+      *piCol += (iIncr-2);
+    }
+  }else{
+    while( 1 ){
+      int dummy;
+      if( pIter->a>=pIter->b ){
+        *piCol = -1;
+        return;
+      }
+      if( pIter->a[0]==0x01 ) break;
+      pIter->a += fts5GetVarint32(pIter->a, dummy);
+    }
+    pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+  }
+}
+
+static int fts5ApiPhraseFirstColumn(
+  Fts5Context *pCtx, 
+  int iPhrase, 
+  Fts5PhraseIter *pIter, 
+  int *piCol
+){
+  int rc = SQLITE_OK;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
+
+  if( pConfig->eDetail==FTS5_DETAIL_COLUMNS ){
+    Fts5Sorter *pSorter = pCsr->pSorter;
+    int n;
+    if( pSorter ){
+      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
+      n = pSorter->aIdx[iPhrase] - i1;
+      pIter->a = &pSorter->aPoslist[i1];
+    }else{
+      rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, iPhrase, &pIter->a, &n);
+    }
+    if( rc==SQLITE_OK ){
+      pIter->b = &pIter->a[n];
+      *piCol = 0;
+      fts5ApiPhraseNextColumn(pCtx, pIter, piCol);
+    }
+  }else{
+    int n;
+    rc = fts5CsrPoslist(pCsr, iPhrase, &pIter->a, &n);
+    if( rc==SQLITE_OK ){
+      pIter->b = &pIter->a[n];
+      if( n<=0 ){
+        *piCol = -1;
+      }else if( pIter->a[0]==0x01 ){
+        pIter->a += 1 + fts5GetVarint32(&pIter->a[1], *piCol);
+      }else{
+        *piCol = 0;
+      }
+    }
+  }
+
+  return rc;
+}
+
+
+static int fts5ApiQueryPhrase(Fts5Context*, int, void*, 
+    int(*)(const Fts5ExtensionApi*, Fts5Context*, void*)
+);
+
+static const Fts5ExtensionApi sFts5Api = {
+  2,                            /* iVersion */
+  fts5ApiUserData,
+  fts5ApiColumnCount,
+  fts5ApiRowCount,
+  fts5ApiColumnTotalSize,
+  fts5ApiTokenize,
+  fts5ApiPhraseCount,
+  fts5ApiPhraseSize,
+  fts5ApiInstCount,
+  fts5ApiInst,
+  fts5ApiRowid,
+  fts5ApiColumnText,
+  fts5ApiColumnSize,
+  fts5ApiQueryPhrase,
+  fts5ApiSetAuxdata,
+  fts5ApiGetAuxdata,
+  fts5ApiPhraseFirst,
+  fts5ApiPhraseNext,
+  fts5ApiPhraseFirstColumn,
+  fts5ApiPhraseNextColumn,
+};
+
+/*
+** Implementation of API function xQueryPhrase().
+*/
+static int fts5ApiQueryPhrase(
+  Fts5Context *pCtx, 
+  int iPhrase, 
+  void *pUserData,
+  int(*xCallback)(const Fts5ExtensionApi*, Fts5Context*, void*)
+){
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
+  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
+  int rc;
+  Fts5Cursor *pNew = 0;
+
+  rc = fts5OpenMethod(pCsr->base.pVtab, (sqlite3_vtab_cursor**)&pNew);
+  if( rc==SQLITE_OK ){
+    pNew->ePlan = FTS5_PLAN_MATCH;
+    pNew->iFirstRowid = SMALLEST_INT64;
+    pNew->iLastRowid = LARGEST_INT64;
+    pNew->base.pVtab = (sqlite3_vtab*)pTab;
+    rc = sqlite3Fts5ExprClonePhrase(pCsr->pExpr, iPhrase, &pNew->pExpr);
+  }
+
+  if( rc==SQLITE_OK ){
+    for(rc = fts5CursorFirst(pTab, pNew, 0);
+        rc==SQLITE_OK && CsrFlagTest(pNew, FTS5CSR_EOF)==0;
+        rc = fts5NextMethod((sqlite3_vtab_cursor*)pNew)
+    ){
+      rc = xCallback(&sFts5Api, (Fts5Context*)pNew, pUserData);
+      if( rc!=SQLITE_OK ){
+        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
+        break;
+      }
+    }
+  }
+
+  fts5CloseMethod((sqlite3_vtab_cursor*)pNew);
+  return rc;
+}
+
+static void fts5ApiInvoke(
+  Fts5Auxiliary *pAux,
+  Fts5Cursor *pCsr,
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert( pCsr->pAux==0 );
+  pCsr->pAux = pAux;
+  pAux->xFunc(&sFts5Api, (Fts5Context*)pCsr, context, argc, argv);
+  pCsr->pAux = 0;
+}
+
+static Fts5Cursor *fts5CursorFromCsrid(Fts5Global *pGlobal, i64 iCsrId){
+  Fts5Cursor *pCsr;
+  for(pCsr=pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
+    if( pCsr->iCsrId==iCsrId ) break;
+  }
+  return pCsr;
+}
+
+static void fts5ApiCallback(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+
+  Fts5Auxiliary *pAux;
+  Fts5Cursor *pCsr;
+  i64 iCsrId;
+
+  assert( argc>=1 );
+  pAux = (Fts5Auxiliary*)sqlite3_user_data(context);
+  iCsrId = sqlite3_value_int64(argv[0]);
+
+  pCsr = fts5CursorFromCsrid(pAux->pGlobal, iCsrId);
+  if( pCsr==0 ){
+    char *zErr = sqlite3_mprintf("no such cursor: %lld", iCsrId);
+    sqlite3_result_error(context, zErr, -1);
+    sqlite3_free(zErr);
+  }else{
+    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
+  }
+}
+
+
+/*
+** Given cursor id iId, return a pointer to the corresponding Fts5Index 
+** object. Or NULL If the cursor id does not exist.
+**
+** If successful, set *ppConfig to point to the associated config object 
+** before returning.
+*/
+Fts5Index *sqlite3Fts5IndexFromCsrid(
+  Fts5Global *pGlobal,            /* FTS5 global context for db handle */
+  i64 iCsrId,                     /* Id of cursor to find */
+  Fts5Config **ppConfig           /* OUT: Configuration object */
+){
+  Fts5Cursor *pCsr;
+  Fts5Table *pTab;
+
+  pCsr = fts5CursorFromCsrid(pGlobal, iCsrId);
+  pTab = (Fts5Table*)pCsr->base.pVtab;
+  *ppConfig = pTab->pConfig;
+
+  return pTab->pIndex;
+}
+
+/*
+** Return a "position-list blob" corresponding to the current position of
+** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
+** the current position-list for each phrase in the query associated with
+** cursor pCsr.
+**
+** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
+** the number of phrases in the query. Following the varints are the
+** concatenated position lists for each phrase, in order.
+**
+** The first varint (if it exists) contains the size of the position list
+** for phrase 0. The second (same disclaimer) contains the size of position
+** list 1. And so on. There is no size field for the final position list,
+** as it can be derived from the total size of the blob.
+*/
+static int fts5PoslistBlob(sqlite3_context *pCtx, Fts5Cursor *pCsr){
+  int i;
+  int rc = SQLITE_OK;
+  int nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
+  Fts5Buffer val;
+
+  memset(&val, 0, sizeof(Fts5Buffer));
+  switch( ((Fts5Table*)(pCsr->base.pVtab))->pConfig->eDetail ){
+    case FTS5_DETAIL_FULL:
+
+      /* Append the varints */
+      for(i=0; i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &dummy);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        nPoslist = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &pPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    case FTS5_DETAIL_COLUMNS:
+
+      /* Append the varints */
+      for(i=0; rc==SQLITE_OK && i<(nPhrase-1); i++){
+        const u8 *dummy;
+        int nByte;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &dummy, &nByte);
+        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
+      }
+
+      /* Append the position lists */
+      for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
+        const u8 *pPoslist;
+        int nPoslist;
+        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &pPoslist, &nPoslist);
+        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
+      }
+      break;
+
+    default:
+      break;
+  }
+
+  sqlite3_result_blob(pCtx, val.p, val.n, sqlite3_free);
+  return rc;
+}
+
+/* 
+** This is the xColumn method, called by SQLite to request a value from
+** the row that the supplied cursor currently points to.
+*/
+static int fts5ColumnMethod(
+  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
+  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
+  int iCol                        /* Index of column to read value from */
+){
+  Fts5Table *pTab = (Fts5Table*)(pCursor->pVtab);
+  Fts5Config *pConfig = pTab->pConfig;
+  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
+  int rc = SQLITE_OK;
+  
+  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
+
+  if( pCsr->ePlan==FTS5_PLAN_SPECIAL ){
+    if( iCol==pConfig->nCol ){
+      sqlite3_result_int64(pCtx, pCsr->iSpecial);
+    }
+  }else
+
+  if( iCol==pConfig->nCol ){
+    /* User is requesting the value of the special column with the same name
+    ** as the table. Return the cursor integer id number. This value is only
+    ** useful in that it may be passed as the first argument to an FTS5
+    ** auxiliary function.  */
+    sqlite3_result_int64(pCtx, pCsr->iCsrId);
+  }else if( iCol==pConfig->nCol+1 ){
+
+    /* The value of the "rank" column. */
+    if( pCsr->ePlan==FTS5_PLAN_SOURCE ){
+      fts5PoslistBlob(pCtx, pCsr);
+    }else if( 
+        pCsr->ePlan==FTS5_PLAN_MATCH
+     || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
+    ){
+      if( pCsr->pRank || SQLITE_OK==(rc = fts5FindRankFunction(pCsr)) ){
+        fts5ApiInvoke(pCsr->pRank, pCsr, pCtx, pCsr->nRankArg, pCsr->apRankArg);
+      }
+    }
+  }else if( !fts5IsContentless(pTab) ){
+    rc = fts5SeekCursor(pCsr, 1);
+    if( rc==SQLITE_OK ){
+      sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1));
+    }
+  }
+  return rc;
+}
+
+
+/*
+** This routine implements the xFindFunction method for the FTS3
+** virtual table.
+*/
+static int fts5FindFunctionMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nUnused,                    /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* OUT: User data for *pxFunc */
+){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  Fts5Auxiliary *pAux;
+
+  UNUSED_PARAM(nUnused);
+  pAux = fts5FindAuxiliary(pTab, zName);
+  if( pAux ){
+    *pxFunc = fts5ApiCallback;
+    *ppArg = (void*)pAux;
+    return 1;
+  }
+
+  /* No function of the specified name was found. Return 0. */
+  return 0;
+}
+
+/*
+** Implementation of FTS5 xRename method. Rename an fts5 table.
+*/
+static int fts5RenameMethod(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  const char *zName               /* New name of table */
+){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  return sqlite3Fts5StorageRename(pTab->pStorage, zName);
+}
+
+/*
+** The xSavepoint() method.
+**
+** Flush the contents of the pending-terms table to disk.
+*/
+static int fts5SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  UNUSED_PARAM(iSavepoint);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState(pTab, FTS5_SAVEPOINT, iSavepoint);
+  fts5TripCursors(pTab);
+  return sqlite3Fts5StorageSync(pTab->pStorage, 0);
+}
+
+/*
+** The xRelease() method.
+**
+** This is a no-op.
+*/
+static int fts5ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  UNUSED_PARAM(iSavepoint);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState(pTab, FTS5_RELEASE, iSavepoint);
+  fts5TripCursors(pTab);
+  return sqlite3Fts5StorageSync(pTab->pStorage, 0);
+}
+
+/*
+** The xRollbackTo() method.
+**
+** Discard the contents of the pending terms table.
+*/
+static int fts5RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
+  Fts5Table *pTab = (Fts5Table*)pVtab;
+  UNUSED_PARAM(iSavepoint);  /* Call below is a no-op for NDEBUG builds */
+  fts5CheckTransactionState(pTab, FTS5_ROLLBACKTO, iSavepoint);
+  fts5TripCursors(pTab);
+  return sqlite3Fts5StorageRollback(pTab->pStorage);
+}
+
+/*
+** Register a new auxiliary function with global context pGlobal.
+*/
+static int fts5CreateAux(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_extension_function xFunc,  /* Aux. function implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  int rc = sqlite3_overload_function(pGlobal->db, zName, -1);
+  if( rc==SQLITE_OK ){
+    Fts5Auxiliary *pAux;
+    int nName;                      /* Size of zName in bytes, including \0 */
+    int nByte;                      /* Bytes of space to allocate */
+
+    nName = (int)strlen(zName) + 1;
+    nByte = sizeof(Fts5Auxiliary) + nName;
+    pAux = (Fts5Auxiliary*)sqlite3_malloc(nByte);
+    if( pAux ){
+      memset(pAux, 0, nByte);
+      pAux->zFunc = (char*)&pAux[1];
+      memcpy(pAux->zFunc, zName, nName);
+      pAux->pGlobal = pGlobal;
+      pAux->pUserData = pUserData;
+      pAux->xFunc = xFunc;
+      pAux->xDestroy = xDestroy;
+      pAux->pNext = pGlobal->pAux;
+      pGlobal->pAux = pAux;
+    }else{
+      rc = SQLITE_NOMEM;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Register a new tokenizer. This is the implementation of the 
+** fts5_api.xCreateTokenizer() method.
+*/
+static int fts5CreateTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void *pUserData,                /* User data for aux. function */
+  fts5_tokenizer *pTokenizer,     /* Tokenizer implementation */
+  void(*xDestroy)(void*)          /* Destructor for pUserData */
+){
+  Fts5Global *pGlobal = (Fts5Global*)pApi;
+  Fts5TokenizerModule *pNew;
+  int nName;                      /* Size of zName and its \0 terminator */
+  int nByte;                      /* Bytes of space to allocate */
+  int rc = SQLITE_OK;
+
+  nName = (int)strlen(zName) + 1;
+  nByte = sizeof(Fts5TokenizerModule) + nName;
+  pNew = (Fts5TokenizerModule*)sqlite3_malloc(nByte);
+  if( pNew ){
+    memset(pNew, 0, nByte);
+    pNew->zName = (char*)&pNew[1];
+    memcpy(pNew->zName, zName, nName);
+    pNew->pUserData = pUserData;
+    pNew->x = *pTokenizer;
+    pNew->xDestroy = xDestroy;
+    pNew->pNext = pGlobal->pTok;
+    pGlobal->pTok = pNew;
+    if( pNew->pNext==0 ){
+      pGlobal->pDfltTok = pNew;
+    }
+  }else{
+    rc = SQLITE_NOMEM;
+  }
+
+  return rc;
+}
+
+static Fts5TokenizerModule *fts5LocateTokenizer(
+  Fts5Global *pGlobal, 
+  const char *zName
+){
+  Fts5TokenizerModule *pMod = 0;
+
+  if( zName==0 ){
+    pMod = pGlobal->pDfltTok;
+  }else{
+    for(pMod=pGlobal->pTok; pMod; pMod=pMod->pNext){
+      if( sqlite3_stricmp(zName, pMod->zName)==0 ) break;
+    }
+  }
+
+  return pMod;
+}
+
+/*
+** Find a tokenizer. This is the implementation of the 
+** fts5_api.xFindTokenizer() method.
+*/
+static int fts5FindTokenizer(
+  fts5_api *pApi,                 /* Global context (one per db handle) */
+  const char *zName,              /* Name of new function */
+  void **ppUserData,
+  fts5_tokenizer *pTokenizer      /* Populate this object */
+){
+  int rc = SQLITE_OK;
+  Fts5TokenizerModule *pMod;
+
+  pMod = fts5LocateTokenizer((Fts5Global*)pApi, zName);
+  if( pMod ){
+    *pTokenizer = pMod->x;
+    *ppUserData = pMod->pUserData;
+  }else{
+    memset(pTokenizer, 0, sizeof(fts5_tokenizer));
+    rc = SQLITE_ERROR;
+  }
+
+  return rc;
+}
+
+int sqlite3Fts5GetTokenizer(
+  Fts5Global *pGlobal, 
+  const char **azArg,
+  int nArg,
+  Fts5Tokenizer **ppTok,
+  fts5_tokenizer **ppTokApi,
+  char **pzErr
+){
+  Fts5TokenizerModule *pMod;
+  int rc = SQLITE_OK;
+
+  pMod = fts5LocateTokenizer(pGlobal, nArg==0 ? 0 : azArg[0]);
+  if( pMod==0 ){
+    assert( nArg>0 );
+    rc = SQLITE_ERROR;
+    *pzErr = sqlite3_mprintf("no such tokenizer: %s", azArg[0]);
+  }else{
+    rc = pMod->x.xCreate(pMod->pUserData, &azArg[1], (nArg?nArg-1:0), ppTok);
+    *ppTokApi = &pMod->x;
+    if( rc!=SQLITE_OK && pzErr ){
+      *pzErr = sqlite3_mprintf("error in tokenizer constructor");
+    }
+  }
+
+  if( rc!=SQLITE_OK ){
+    *ppTokApi = 0;
+    *ppTok = 0;
+  }
+
+  return rc;
+}
+
+static void fts5ModuleDestroy(void *pCtx){
+  Fts5TokenizerModule *pTok, *pNextTok;
+  Fts5Auxiliary *pAux, *pNextAux;
+  Fts5Global *pGlobal = (Fts5Global*)pCtx;
+
+  for(pAux=pGlobal->pAux; pAux; pAux=pNextAux){
+    pNextAux = pAux->pNext;
+    if( pAux->xDestroy ) pAux->xDestroy(pAux->pUserData);
+    sqlite3_free(pAux);
+  }
+
+  for(pTok=pGlobal->pTok; pTok; pTok=pNextTok){
+    pNextTok = pTok->pNext;
+    if( pTok->xDestroy ) pTok->xDestroy(pTok->pUserData);
+    sqlite3_free(pTok);
+  }
+
+  sqlite3_free(pGlobal);
+}
+
+static void fts5Fts5Func(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apUnused        /* Function arguments */
+){
+  Fts5Global *pGlobal = (Fts5Global*)sqlite3_user_data(pCtx);
+  char buf[8];
+  UNUSED_PARAM2(nArg, apUnused);
+  assert( nArg==0 );
+  assert( sizeof(buf)>=sizeof(pGlobal) );
+  memcpy(buf, (void*)&pGlobal, sizeof(pGlobal));
+  sqlite3_result_blob(pCtx, buf, sizeof(pGlobal), SQLITE_TRANSIENT);
+}
+
+/*
+** Implementation of fts5_source_id() function.
+*/
+static void fts5SourceIdFunc(
+  sqlite3_context *pCtx,          /* Function call context */
+  int nArg,                       /* Number of args */
+  sqlite3_value **apUnused        /* Function arguments */
+){
+  assert( nArg==0 );
+  UNUSED_PARAM2(nArg, apUnused);
+  sqlite3_result_text(pCtx, "--FTS5-SOURCE-ID--", -1, SQLITE_TRANSIENT);
+}
+
+static int fts5Init(sqlite3 *db){
+  static const sqlite3_module fts5Mod = {
+    /* iVersion      */ 2,
+    /* xCreate       */ fts5CreateMethod,
+    /* xConnect      */ fts5ConnectMethod,
+    /* xBestIndex    */ fts5BestIndexMethod,
+    /* xDisconnect   */ fts5DisconnectMethod,
+    /* xDestroy      */ fts5DestroyMethod,
+    /* xOpen         */ fts5OpenMethod,
+    /* xClose        */ fts5CloseMethod,
+    /* xFilter       */ fts5FilterMethod,
+    /* xNext         */ fts5NextMethod,
+    /* xEof          */ fts5EofMethod,
+    /* xColumn       */ fts5ColumnMethod,
+    /* xRowid        */ fts5RowidMethod,
+    /* xUpdate       */ fts5UpdateMethod,
+    /* xBegin        */ fts5BeginMethod,
+    /* xSync         */ fts5SyncMethod,
+    /* xCommit       */ fts5CommitMethod,
+    /* xRollback     */ fts5RollbackMethod,
+    /* xFindFunction */ fts5FindFunctionMethod,
+    /* xRename       */ fts5RenameMethod,
+    /* xSavepoint    */ fts5SavepointMethod,
+    /* xRelease      */ fts5ReleaseMethod,
+    /* xRollbackTo   */ fts5RollbackToMethod,
+  };
+
+  int rc;
+  Fts5Global *pGlobal = 0;
+
+  pGlobal = (Fts5Global*)sqlite3_malloc(sizeof(Fts5Global));
+  if( pGlobal==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    void *p = (void*)pGlobal;
+    memset(pGlobal, 0, sizeof(Fts5Global));
+    pGlobal->db = db;
+    pGlobal->api.iVersion = 2;
+    pGlobal->api.xCreateFunction = fts5CreateAux;
+    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
+    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
+    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5TokenizerInit(&pGlobal->api);
+    if( rc==SQLITE_OK ) rc = sqlite3Fts5VocabInit(pGlobal, db);
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5", 0, SQLITE_UTF8, p, fts5Fts5Func, 0, 0
+      );
+    }
+    if( rc==SQLITE_OK ){
+      rc = sqlite3_create_function(
+          db, "fts5_source_id", 0, SQLITE_UTF8, p, fts5SourceIdFunc, 0, 0
+      );
+    }
+  }
+
+  /* If SQLITE_FTS5_ENABLE_TEST_MI is defined, assume that the file
+  ** fts5_test_mi.c is compiled and linked into the executable. And call
+  ** its entry point to enable the matchinfo() demo.  */
+#ifdef SQLITE_FTS5_ENABLE_TEST_MI
+  if( rc==SQLITE_OK ){
+    extern int sqlite3Fts5TestRegisterMatchinfo(sqlite3*);
+    rc = sqlite3Fts5TestRegisterMatchinfo(db);
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** The following functions are used to register the module with SQLite. If
+** this module is being built as part of the SQLite core (SQLITE_CORE is
+** defined), then sqlite3_open() will call sqlite3Fts5Init() directly.
+**
+** Or, if this module is being built as a loadable extension, 
+** sqlite3Fts5Init() is omitted and the two standard entry points
+** sqlite3_fts_init() and sqlite3_fts5_init() defined instead.
+*/
+#ifndef SQLITE_CORE
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_fts_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_fts5_init(
+  sqlite3 *db,
+  char **pzErrMsg,
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return fts5Init(db);
+}
+#else
+int sqlite3Fts5Init(sqlite3 *db){
+  return fts5Init(db);
+}
+#endif