**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.795 2008/12/10 19:26:24 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................

/* Opcode:  Return P1 * * * *
**
** Jump to the next instruction after the address in register P1.
*/
case OP_Return: {           /* in1 */
  assert( pIn1->flags & MEM_Int );
  pc = pIn1->u.i;
  break;
}

/* Opcode:  Yield P1 * * * *
**
** Swap the program counter with the value in register P1.
*/
................................................................................
case OP_Yield: {
  int pcDest;
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  assert( (pIn1->flags & MEM_Dyn)==0 );
  pIn1->flags = MEM_Int;
  pcDest = pIn1->u.i;
  pIn1->u.i = pc;
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pcDest;
  break;
}


................................................................................
  ExpandBlob(pIn2);
  Stringify(pIn2, encoding);
  nByte = pIn1->n + pIn2->n;
  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
    goto too_big;
  }
  MemSetTypeFlag(pOut, MEM_Str);
  if( sqlite3VdbeMemGrow(pOut, nByte+2, pOut==pIn2) ){
    goto no_mem;
  }
  if( pOut!=pIn2 ){
    memcpy(pOut->z, pIn2->z, pIn2->n);
  }
  memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
  pOut->z[nByte] = 0;
  pOut->z[nByte+1] = 0;
  pOut->flags |= MEM_Term;
  pOut->n = nByte;
  pOut->enc = encoding;
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Add P1 P2 P3 * *
**
................................................................................
        break;
      }
      default: {
        i64 ia = (i64)a;
        i64 ib = (i64)b;
        if( ia==0 ) goto arithmetic_result_is_null;
        if( ia==-1 ) ia = 1;
        b = ib % ia;
        break;
      }
    }
    if( sqlite3IsNaN(b) ){
      goto arithmetic_result_is_null;
    }
    pOut->r = b;
................................................................................
      payloadSize = 0;
    }else if( pC->cacheStatus==p->cacheCtr ){
      payloadSize = pC->payloadSize;
      zRec = (char*)pC->aRow;
    }else if( pC->isIndex ){
      i64 payloadSize64;
      sqlite3BtreeKeySize(pCrsr, &payloadSize64);
      payloadSize = payloadSize64;
    }else{
      sqlite3BtreeDataSize(pCrsr, (u32 *)&payloadSize);
    }
    nField = pC->nField;
  }else{
    assert( pC->pseudoTable );
    /* The record is the sole entry of a pseudo-table */
................................................................................
  /* Make sure the output register has a buffer large enough to store 
  ** the new record. The output register (pOp->p3) is not allowed to
  ** be one of the input registers (because the following call to
  ** sqlite3VdbeMemGrow() could clobber the value before it is used).
  */
  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
  pOut = &p->aMem[pOp->p3];
  if( sqlite3VdbeMemGrow(pOut, nByte, 0) ){
    goto no_mem;
  }
  zNewRecord = (u8 *)pOut->z;

  /* Write the record */
  i = putVarint32(zNewRecord, nHdr);
  for(pRec=pData0; pRec<=pLast; pRec++){
    serial_type = sqlite3VdbeSerialType(pRec, file_format);
    i += putVarint32(&zNewRecord[i], serial_type);      /* serial type */
  }
  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
    i += sqlite3VdbeSerialPut(&zNewRecord[i], nByte-i, pRec, file_format);
  }
  assert( i==nByte );

  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pOut->n = nByte;
  pOut->flags = MEM_Blob | MEM_Dyn;
  pOut->xDel = 0;
  if( nZero ){
    pOut->u.nZero = nZero;
    pOut->flags |= MEM_Zero;
  }
  pOut->enc = SQLITE_UTF8;  /* In case the blob is ever converted to text */
................................................................................
      assert( desiredAutoCommit==1 );
      sqlite3RollbackAll(db);
      db->autoCommit = 1;
    }else{
      db->autoCommit = desiredAutoCommit;
      if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
        p->pc = pc;
        db->autoCommit = 1-desiredAutoCommit;
        p->rc = rc = SQLITE_BUSY;
        goto vdbe_return;
      }
    }
    if( p->rc==SQLITE_OK ){
      rc = SQLITE_DONE;
    }else{
................................................................................
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  sqlite3VdbeMemIntegerify(pIn3);
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pIn3->u.i);
  if( pOp->p2==0 ){
    /* When the schema cookie changes, record the new cookie internally */
    pDb->pSchema->schema_cookie = pIn3->u.i;
    db->flags |= SQLITE_InternChanges;
  }else if( pOp->p2==1 ){
    /* Record changes in the file format */
    pDb->pSchema->file_format = pIn3->u.i;
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */
    sqlite3ExpirePreparedStatements(db);
  }
  break;
................................................................................
    wrFlag = 0;
  }
  if( pOp->p5 ){
    assert( p2>0 );
    assert( p2<=p->nMem );
    pIn2 = &p->aMem[p2];
    sqlite3VdbeMemIntegerify(pIn2);
    p2 = pIn2->u.i;
    if( p2<2 ) {
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
  }
  assert( i>=0 );
  pCur = allocateCursor(p, i, &pOp[-1], iDb, 1);
................................................................................
      ** 2 (zerodata for indices).  If these conditions are not met it can
      ** only mean that we are dealing with a corrupt database file
      */
      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
        rc = SQLITE_CORRUPT_BKPT;
        goto abort_due_to_error;
      }
      pCur->isTable = (flags & BTREE_INTKEY)!=0;
      pCur->isIndex = (flags & BTREE_ZERODATA)!=0;
      /* If P4==0 it means we are expected to open a table.  If P4!=0 then
      ** we expect to be opening an index.  If this is not what happened,
      ** then the database is corrupt
      */
      if( (pCur->isTable && pOp->p4type==P4_KEYINFO)
       || (pCur->isIndex && pOp->p4type!=P4_KEYINFO) ){
        rc = SQLITE_CORRUPT_BKPT;
................................................................................
  int i = pOp->p1;
  VdbeCursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i, &pOp[-1], -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  pCx->ephemPseudoTable = pOp->p2;
  pCx->isTable = 1;
  pCx->isIndex = 0;
  break;
}

/* Opcode: Close P1 * * * *
**
................................................................................
        break;
      }
      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, 0, (u64)iKey, 0, &res);
      if( rc!=SQLITE_OK ){
        goto abort_due_to_error;
      }
      pC->lastRowid = iKey;
      pC->rowidIsValid = res==0;
    }else{
      UnpackedRecord r;
      int nField = pOp->p4.i;
      assert( pOp->p4type==P4_INT32 );
      assert( nField>0 );
      r.pKeyInfo = pC->pKeyInfo;
      r.nField = nField;
      if( oc==OP_MoveGt || oc==OP_MoveLe ){
        r.flags = UNPACKED_INCRKEY;
      }else{
        r.flags = 0;
      }
      r.aMem = &p->aMem[pOp->p3];
      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, &r, 0, 0, &res);
................................................................................
    int res;
    u64 iKey;
    assert( pIn3->flags & MEM_Int );
    assert( p->apCsr[i]->isTable );
    iKey = intToKey(pIn3->u.i);
    rc = sqlite3BtreeMovetoUnpacked(pCrsr, 0, iKey, 0,&res);
    pC->lastRowid = pIn3->u.i;
    pC->rowidIsValid = res==0;
    pC->nullRow = 0;
    pC->cacheStatus = CACHE_STALE;
    /* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
    ** processing is about to abort so we really do not care whether or not
    ** the following jump is taken.  (In other words, do not stress over
    ** the error that valgrind sometimes shows on the next statement when
    ** running ioerr.test and similar failure-recovery test scripts.) */
................................................................................
  if( pC->isIndex ){
    i64 n64;
    assert( !pC->isTable );
    sqlite3BtreeKeySize(pCrsr, &n64);
    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
      goto too_big;
    }
    n = n64;
  }else{
    sqlite3BtreeDataSize(pCrsr, &n);
    if( (int)n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
      goto too_big;
    }
  }
  if( sqlite3VdbeMemGrow(pOut, n, 0) ){
................................................................................

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pCrsr = pC->pCursor;
  assert( pCrsr!=0 );
  rc = sqlite3BtreeLast(pCrsr, &res);
  pC->nullRow = res;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  if( res && pOp->p2>0 ){
    pc = pOp->p2 - 1;
  }
  break;
}
................................................................................
  int res;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( (pCrsr = pC->pCursor)!=0 ){
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->atFirst = res==0;
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
  }else{
    res = 1;
  }
  pC->nullRow = res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){
    pc = pOp->p2 - 1;
  }
  break;
}

................................................................................
  }
  pCrsr = pC->pCursor;
  assert( pCrsr );
  res = 1;
  assert( pC->deferredMoveto==0 );
  rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
                              sqlite3BtreePrevious(pCrsr, &res);
  pC->nullRow = res;
  pC->cacheStatus = CACHE_STALE;
  if( res==0 ){
    pc = pOp->p2 - 1;
    if( pOp->p5 ) p->aCounter[pOp->p5-1]++;
#ifdef SQLITE_TEST
    sqlite3_search_count++;
#endif
................................................................................
  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    UnpackedRecord r;
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = pOp->p3;
    r.flags = 0;
    r.aMem = &p->aMem[pOp->p2];
    rc = sqlite3BtreeMovetoUnpacked(pCrsr, &r, 0, 0, &res);
    if( rc==SQLITE_OK && res==0 ){
      rc = sqlite3BtreeDelete(pCrsr);
    }
    assert( pC->deferredMoveto==0 );
................................................................................
  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res;
    UnpackedRecord r;
    assert( pC->deferredMoveto==0 );
    assert( pOp->p5==0 || pOp->p5==1 );
    assert( pOp->p4type==P4_INT32 );
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = pOp->p4.i;
    if( pOp->p5 ){
      r.flags = UNPACKED_INCRKEY | UNPACKED_IGNORE_ROWID;
    }else{
      r.flags = UNPACKED_IGNORE_ROWID;
    }
    r.aMem = &p->aMem[pOp->p3];
    rc = sqlite3VdbeIdxKeyCompare(pC, &r, &res);
................................................................................
  if( aRoot==0 ) goto no_mem;
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pnErr = &p->aMem[pOp->p3];
  assert( (pnErr->flags & MEM_Int)!=0 );
  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
  pIn1 = &p->aMem[pOp->p1];
  for(j=0; j<nRoot; j++){
    aRoot[j] = sqlite3VdbeIntValue(&pIn1[j]);
  }
  aRoot[j] = 0;
  assert( pOp->p5<db->nDb );
  assert( (p->btreeMask & (1<<pOp->p5))!=0 );
  z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, aRoot, nRoot,
                                 pnErr->u.i, &nErr);
  sqlite3DbFree(db, aRoot);
  pnErr->u.i -= nErr;
  sqlite3VdbeMemSetNull(pIn1);
  if( nErr==0 ){
    assert( z==0 );
  }else if( z==0 ){
    goto no_mem;
................................................................................
** P2 contains the root-page of the table to lock.
**
** P4 contains a pointer to the name of the table being locked. This is only
** used to generate an error message if the lock cannot be obtained.
*/
case OP_TableLock: {
  int p1 = pOp->p1; 
  u8 isWriteLock = pOp->p3;
  assert( p1>=0 && p1<db->nDb );
  assert( (p->btreeMask & (1<<p1))!=0 );
  assert( isWriteLock==0 || isWriteLock==1 );
  rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
  if( rc==SQLITE_LOCKED ){
    const char *z = pOp->p4.z;
    sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
................................................................................
  assert( pCur->pVtabCursor );
  pVtabCursor = pCur->pVtabCursor;
  pVtab = pVtabCursor->pVtab;
  pModule = pVtab->pModule;

  /* Grab the index number and argc parameters */
  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
  nArg = pArgc->u.i;
  iQuery = pQuery->u.i;

  /* Invoke the xFilter method */
  {
    int res = 0;
    int i;
    Mem **apArg = p->apArg;
    for(i = 0; i<nArg; i++){

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.796 2008/12/10 22:32:56 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................

/* Opcode:  Return P1 * * * *
**
** Jump to the next instruction after the address in register P1.
*/
case OP_Return: {           /* in1 */
  assert( pIn1->flags & MEM_Int );
  pc = (int)pIn1->u.i;
  break;
}

/* Opcode:  Yield P1 * * * *
**
** Swap the program counter with the value in register P1.
*/
................................................................................
case OP_Yield: {
  int pcDest;
  assert( pOp->p1>0 );
  assert( pOp->p1<=p->nMem );
  pIn1 = &p->aMem[pOp->p1];
  assert( (pIn1->flags & MEM_Dyn)==0 );
  pIn1->flags = MEM_Int;
  pcDest = (int)pIn1->u.i;
  pIn1->u.i = pc;
  REGISTER_TRACE(pOp->p1, pIn1);
  pc = pcDest;
  break;
}


................................................................................
  ExpandBlob(pIn2);
  Stringify(pIn2, encoding);
  nByte = pIn1->n + pIn2->n;
  if( nByte>db->aLimit[SQLITE_LIMIT_LENGTH] ){
    goto too_big;
  }
  MemSetTypeFlag(pOut, MEM_Str);
  if( sqlite3VdbeMemGrow(pOut, (int)nByte+2, pOut==pIn2) ){
    goto no_mem;
  }
  if( pOut!=pIn2 ){
    memcpy(pOut->z, pIn2->z, pIn2->n);
  }
  memcpy(&pOut->z[pIn2->n], pIn1->z, pIn1->n);
  pOut->z[nByte] = 0;
  pOut->z[nByte+1] = 0;
  pOut->flags |= MEM_Term;
  pOut->n = (int)nByte;
  pOut->enc = encoding;
  UPDATE_MAX_BLOBSIZE(pOut);
  break;
}

/* Opcode: Add P1 P2 P3 * *
**
................................................................................
        break;
      }
      default: {
        i64 ia = (i64)a;
        i64 ib = (i64)b;
        if( ia==0 ) goto arithmetic_result_is_null;
        if( ia==-1 ) ia = 1;
        b = (double)(ib % ia);
        break;
      }
    }
    if( sqlite3IsNaN(b) ){
      goto arithmetic_result_is_null;
    }
    pOut->r = b;
................................................................................
      payloadSize = 0;
    }else if( pC->cacheStatus==p->cacheCtr ){
      payloadSize = pC->payloadSize;
      zRec = (char*)pC->aRow;
    }else if( pC->isIndex ){
      i64 payloadSize64;
      sqlite3BtreeKeySize(pCrsr, &payloadSize64);
      payloadSize = (int)payloadSize64;
    }else{
      sqlite3BtreeDataSize(pCrsr, (u32 *)&payloadSize);
    }
    nField = pC->nField;
  }else{
    assert( pC->pseudoTable );
    /* The record is the sole entry of a pseudo-table */
................................................................................
  /* Make sure the output register has a buffer large enough to store 
  ** the new record. The output register (pOp->p3) is not allowed to
  ** be one of the input registers (because the following call to
  ** sqlite3VdbeMemGrow() could clobber the value before it is used).
  */
  assert( pOp->p3<pOp->p1 || pOp->p3>=pOp->p1+pOp->p2 );
  pOut = &p->aMem[pOp->p3];
  if( sqlite3VdbeMemGrow(pOut, (int)nByte, 0) ){
    goto no_mem;
  }
  zNewRecord = (u8 *)pOut->z;

  /* Write the record */
  i = putVarint32(zNewRecord, nHdr);
  for(pRec=pData0; pRec<=pLast; pRec++){
    serial_type = sqlite3VdbeSerialType(pRec, file_format);
    i += putVarint32(&zNewRecord[i], serial_type);      /* serial type */
  }
  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
    i += sqlite3VdbeSerialPut(&zNewRecord[i], (int)(nByte-i), pRec,file_format);
  }
  assert( i==nByte );

  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pOut->n = (int)nByte;
  pOut->flags = MEM_Blob | MEM_Dyn;
  pOut->xDel = 0;
  if( nZero ){
    pOut->u.nZero = nZero;
    pOut->flags |= MEM_Zero;
  }
  pOut->enc = SQLITE_UTF8;  /* In case the blob is ever converted to text */
................................................................................
      assert( desiredAutoCommit==1 );
      sqlite3RollbackAll(db);
      db->autoCommit = 1;
    }else{
      db->autoCommit = desiredAutoCommit;
      if( sqlite3VdbeHalt(p)==SQLITE_BUSY ){
        p->pc = pc;
        db->autoCommit = (u8)(1-desiredAutoCommit);
        p->rc = rc = SQLITE_BUSY;
        goto vdbe_return;
      }
    }
    if( p->rc==SQLITE_OK ){
      rc = SQLITE_DONE;
    }else{
................................................................................
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  sqlite3VdbeMemIntegerify(pIn3);
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, 1+pOp->p2, (int)pIn3->u.i);
  if( pOp->p2==0 ){
    /* When the schema cookie changes, record the new cookie internally */
    pDb->pSchema->schema_cookie = (int)pIn3->u.i;
    db->flags |= SQLITE_InternChanges;
  }else if( pOp->p2==1 ){
    /* Record changes in the file format */
    pDb->pSchema->file_format = (u8)pIn3->u.i;
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */
    sqlite3ExpirePreparedStatements(db);
  }
  break;
................................................................................
    wrFlag = 0;
  }
  if( pOp->p5 ){
    assert( p2>0 );
    assert( p2<=p->nMem );
    pIn2 = &p->aMem[p2];
    sqlite3VdbeMemIntegerify(pIn2);
    p2 = (int)pIn2->u.i;
    if( p2<2 ) {
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
  }
  assert( i>=0 );
  pCur = allocateCursor(p, i, &pOp[-1], iDb, 1);
................................................................................
      ** 2 (zerodata for indices).  If these conditions are not met it can
      ** only mean that we are dealing with a corrupt database file
      */
      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
        rc = SQLITE_CORRUPT_BKPT;
        goto abort_due_to_error;
      }
      pCur->isTable = (flags & BTREE_INTKEY)!=0 ?1:0;
      pCur->isIndex = (flags & BTREE_ZERODATA)!=0 ?1:0;
      /* If P4==0 it means we are expected to open a table.  If P4!=0 then
      ** we expect to be opening an index.  If this is not what happened,
      ** then the database is corrupt
      */
      if( (pCur->isTable && pOp->p4type==P4_KEYINFO)
       || (pCur->isIndex && pOp->p4type!=P4_KEYINFO) ){
        rc = SQLITE_CORRUPT_BKPT;
................................................................................
  int i = pOp->p1;
  VdbeCursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i, &pOp[-1], -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  pCx->ephemPseudoTable = (u8)pOp->p2;
  pCx->isTable = 1;
  pCx->isIndex = 0;
  break;
}

/* Opcode: Close P1 * * * *
**
................................................................................
        break;
      }
      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, 0, (u64)iKey, 0, &res);
      if( rc!=SQLITE_OK ){
        goto abort_due_to_error;
      }
      pC->lastRowid = iKey;
      pC->rowidIsValid = res==0 ?1:0;
    }else{
      UnpackedRecord r;
      int nField = pOp->p4.i;
      assert( pOp->p4type==P4_INT32 );
      assert( nField>0 );
      r.pKeyInfo = pC->pKeyInfo;
      r.nField = (u16)nField;
      if( oc==OP_MoveGt || oc==OP_MoveLe ){
        r.flags = UNPACKED_INCRKEY;
      }else{
        r.flags = 0;
      }
      r.aMem = &p->aMem[pOp->p3];
      rc = sqlite3BtreeMovetoUnpacked(pC->pCursor, &r, 0, 0, &res);
................................................................................
    int res;
    u64 iKey;
    assert( pIn3->flags & MEM_Int );
    assert( p->apCsr[i]->isTable );
    iKey = intToKey(pIn3->u.i);
    rc = sqlite3BtreeMovetoUnpacked(pCrsr, 0, iKey, 0,&res);
    pC->lastRowid = pIn3->u.i;
    pC->rowidIsValid = res==0 ?1:0;
    pC->nullRow = 0;
    pC->cacheStatus = CACHE_STALE;
    /* res might be uninitialized if rc!=SQLITE_OK.  But if rc!=SQLITE_OK
    ** processing is about to abort so we really do not care whether or not
    ** the following jump is taken.  (In other words, do not stress over
    ** the error that valgrind sometimes shows on the next statement when
    ** running ioerr.test and similar failure-recovery test scripts.) */
................................................................................
  if( pC->isIndex ){
    i64 n64;
    assert( !pC->isTable );
    sqlite3BtreeKeySize(pCrsr, &n64);
    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
      goto too_big;
    }
    n = (int)n64;
  }else{
    sqlite3BtreeDataSize(pCrsr, &n);
    if( (int)n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
      goto too_big;
    }
  }
  if( sqlite3VdbeMemGrow(pOut, n, 0) ){
................................................................................

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pCrsr = pC->pCursor;
  assert( pCrsr!=0 );
  rc = sqlite3BtreeLast(pCrsr, &res);
  pC->nullRow = (u8)res;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  if( res && pOp->p2>0 ){
    pc = pOp->p2 - 1;
  }
  break;
}
................................................................................
  int res;

  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( (pCrsr = pC->pCursor)!=0 ){
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->atFirst = res==0 ?1:0;
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
  }else{
    res = 1;
  }
  pC->nullRow = (u8)res;
  assert( pOp->p2>0 && pOp->p2<p->nOp );
  if( res ){
    pc = pOp->p2 - 1;
  }
  break;
}

................................................................................
  }
  pCrsr = pC->pCursor;
  assert( pCrsr );
  res = 1;
  assert( pC->deferredMoveto==0 );
  rc = pOp->opcode==OP_Next ? sqlite3BtreeNext(pCrsr, &res) :
                              sqlite3BtreePrevious(pCrsr, &res);
  pC->nullRow = (u8)res;
  pC->cacheStatus = CACHE_STALE;
  if( res==0 ){
    pc = pOp->p2 - 1;
    if( pOp->p5 ) p->aCounter[pOp->p5-1]++;
#ifdef SQLITE_TEST
    sqlite3_search_count++;
#endif
................................................................................
  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    UnpackedRecord r;
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p3;
    r.flags = 0;
    r.aMem = &p->aMem[pOp->p2];
    rc = sqlite3BtreeMovetoUnpacked(pCrsr, &r, 0, 0, &res);
    if( rc==SQLITE_OK && res==0 ){
      rc = sqlite3BtreeDelete(pCrsr);
    }
    assert( pC->deferredMoveto==0 );
................................................................................
  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res;
    UnpackedRecord r;
    assert( pC->deferredMoveto==0 );
    assert( pOp->p5==0 || pOp->p5==1 );
    assert( pOp->p4type==P4_INT32 );
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p4.i;
    if( pOp->p5 ){
      r.flags = UNPACKED_INCRKEY | UNPACKED_IGNORE_ROWID;
    }else{
      r.flags = UNPACKED_IGNORE_ROWID;
    }
    r.aMem = &p->aMem[pOp->p3];
    rc = sqlite3VdbeIdxKeyCompare(pC, &r, &res);
................................................................................
  if( aRoot==0 ) goto no_mem;
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pnErr = &p->aMem[pOp->p3];
  assert( (pnErr->flags & MEM_Int)!=0 );
  assert( (pnErr->flags & (MEM_Str|MEM_Blob))==0 );
  pIn1 = &p->aMem[pOp->p1];
  for(j=0; j<nRoot; j++){
    aRoot[j] = (int)sqlite3VdbeIntValue(&pIn1[j]);
  }
  aRoot[j] = 0;
  assert( pOp->p5<db->nDb );
  assert( (p->btreeMask & (1<<pOp->p5))!=0 );
  z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p5].pBt, aRoot, nRoot,
                                 (int)pnErr->u.i, &nErr);
  sqlite3DbFree(db, aRoot);
  pnErr->u.i -= nErr;
  sqlite3VdbeMemSetNull(pIn1);
  if( nErr==0 ){
    assert( z==0 );
  }else if( z==0 ){
    goto no_mem;
................................................................................
** P2 contains the root-page of the table to lock.
**
** P4 contains a pointer to the name of the table being locked. This is only
** used to generate an error message if the lock cannot be obtained.
*/
case OP_TableLock: {
  int p1 = pOp->p1; 
  u8 isWriteLock = (u8)pOp->p3;
  assert( p1>=0 && p1<db->nDb );
  assert( (p->btreeMask & (1<<p1))!=0 );
  assert( isWriteLock==0 || isWriteLock==1 );
  rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
  if( rc==SQLITE_LOCKED ){
    const char *z = pOp->p4.z;
    sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
................................................................................
  assert( pCur->pVtabCursor );
  pVtabCursor = pCur->pVtabCursor;
  pVtab = pVtabCursor->pVtab;
  pModule = pVtab->pModule;

  /* Grab the index number and argc parameters */
  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
  nArg = (int)pArgc->u.i;
  iQuery = (int)pQuery->u.i;

  /* Invoke the xFilter method */
  {
    int res = 0;
    int i;
    Mem **apArg = p->apArg;
    for(i = 0; i<nArg; i++){