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Overview
Comment:Add the vdbe-compress.tcl script which automatically refactors the sqlite3VdbeExec() routine to use less stack space. Use this script when constructing the amalgamation. (CVS 6704)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:7f43391831b03e53d967acee6ae02089740aaedb
User & Date: drh 2009-06-02 15:21:42
Context
2009-06-02
15:47
Add a test case for ticket #3893 and ticket #3894. (CVS 6705) check-in: 2472f6db user: drh tags: trunk
15:21
Add the vdbe-compress.tcl script which automatically refactors the sqlite3VdbeExec() routine to use less stack space. Use this script when constructing the amalgamation. (CVS 6704) check-in: 7f433918 user: drh tags: trunk
2009-06-01
19:53
Avoid allocating large objects on the stack in the incremental BLOB I/O interface. (CVS 6703) check-in: ea7dfde7 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to Makefile.in.

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# all that automatic generation.
#
.target_source:	$(SRC)
	rm -rf tsrc
	mkdir -p tsrc
	cp $(SRC) tsrc
	rm tsrc/sqlite.h.in tsrc/parse.y


	touch .target_source

sqlite3.c:	.target_source $(TOP)/tool/mksqlite3c.tcl
	$(TCLSH_CMD) $(TOP)/tool/mksqlite3c.tcl

# Rules to build the LEMON compiler generator
#







>
>







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# all that automatic generation.
#
.target_source:	$(SRC)
	rm -rf tsrc
	mkdir -p tsrc
	cp $(SRC) tsrc
	rm tsrc/sqlite.h.in tsrc/parse.y
	$(TCLSH_CMD) $(TOP)/tool/vdbe-compress.tcl <tsrc/vdbe.c >vdbe.new
	mv vdbe.new tsrc/vdbe.c
	touch .target_source

sqlite3.c:	.target_source $(TOP)/tool/mksqlite3c.tcl
	$(TCLSH_CMD) $(TOP)/tool/mksqlite3c.tcl

# Rules to build the LEMON compiler generator
#

Changes to main.mk.

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# This target creates a directory named "tsrc" and fills it with
# copies of all of the C source code and header files needed to
# build on the target system.  Some of the C source code and header
# files are automatically generated.  This target takes care of
# all that automatic generation.
#
target_source:	$(SRC)
	rm -rf tsrc
	mkdir tsrc
	cp -f $(SRC) tsrc
	rm tsrc/sqlite.h.in tsrc/parse.y


	touch target_source

sqlite3.c:	target_source $(TOP)/tool/mksqlite3c.tcl
	tclsh $(TOP)/tool/mksqlite3c.tcl
	cp sqlite3.c tclsqlite3.c
	cat $(TOP)/src/tclsqlite.c >>tclsqlite3.c








|




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# This target creates a directory named "tsrc" and fills it with
# copies of all of the C source code and header files needed to
# build on the target system.  Some of the C source code and header
# files are automatically generated.  This target takes care of
# all that automatic generation.
#
target_source:	$(SRC) $(TOP)/tool/vdbe-compress.tcl
	rm -rf tsrc
	mkdir tsrc
	cp -f $(SRC) tsrc
	rm tsrc/sqlite.h.in tsrc/parse.y
	tclsh $(TOP)/tool/vdbe-compress.tcl <tsrc/vdbe.c >vdbe.new
	mv vdbe.new tsrc/vdbe.c
	touch target_source

sqlite3.c:	target_source $(TOP)/tool/mksqlite3c.tcl
	tclsh $(TOP)/tool/mksqlite3c.tcl
	cp sqlite3.c tclsqlite3.c
	cat $(TOP)/src/tclsqlite.c >>tclsqlite3.c

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**
** 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 1.843 2009/05/07 12:17:34 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
................................................................................
#ifdef VDBE_PROFILE
  u64 start;                 /* CPU clock count at start of opcode */
  int origPc;                /* Program counter at start of opcode */
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
#endif

  /* Temporary space into which to unpack a record. */
  char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  assert( db->magic==SQLITE_MAGIC_BUSY );
  sqlite3VdbeMutexArrayEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
................................................................................
** Transfer the values of bound parameters P1..P1+P3-1 into registers
** P2..P2+P3-1.
**
** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {





  int j = pOp->p1 - 1;
  int k = pOp->p2;
  Mem *pVar;
  int n = pOp->p3;
  assert( j>=0 && j+n<=p->nVar );
  assert( k>=1 && k+n-1<=p->nMem );
  assert( pOp->p4.z==0 || pOp->p3==1 );

  while( n-- > 0 ){
    pVar = &p->aVar[j++];
    if( sqlite3VdbeMemTooBig(pVar) ){
      goto too_big;
    }
    pOut = &p->aMem[k++];
    sqlite3VdbeMemReleaseExternal(pOut);
    pOut->flags = MEM_Null;
    sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
    UPDATE_MAX_BLOBSIZE(pOut);
  }
  break;
}
................................................................................
**
** Move the values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P1-1 are
** left holding a NULL.  It is an error for register ranges
** P1..P1+P3-1 and P2..P2+P3-1 to overlap.
*/
case OP_Move: {
  char *zMalloc;




  int n = pOp->p3;
  int p1 = pOp->p1;
  int p2 = pOp->p2;
  assert( n>0 && p1>0 && p2>0 );
  assert( p1+n<=p2 || p2+n<=p1 );

  pIn1 = &p->aMem[p1];
  pOut = &p->aMem[p2];
  while( n-- ){
    assert( pOut<=&p->aMem[p->nMem] );
................................................................................
** If either operand is NULL, the result is NULL.
*/
case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
  int flags;





  applyNumericAffinity(pIn1);
  applyNumericAffinity(pIn2);
  flags = pIn1->flags | pIn2->flags;
  if( (flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
  if( (pIn1->flags & pIn2->flags & MEM_Int)==MEM_Int ){
    i64 a, b;
    a = pIn1->u.i;
    b = pIn2->u.i;
    switch( pOp->opcode ){
      case OP_Add:         b += a;       break;
      case OP_Subtract:    b -= a;       break;
      case OP_Multiply:    b *= a;       break;
      case OP_Divide: {
        if( a==0 ) goto arithmetic_result_is_null;
        /* Dividing the largest possible negative 64-bit integer (1<<63) by 
        ** -1 returns an integer too large to store in a 64-bit data-type. On
        ** some architectures, the value overflows to (1<<63). On others,
        ** a SIGFPE is issued. The following statement normalizes this
        ** behavior so that all architectures behave as if integer 
        ** overflow occurred.
        */
        if( a==-1 && b==SMALLEST_INT64 ) a = 1;
        b /= a;
        break;
      }
      default: {
        if( a==0 ) goto arithmetic_result_is_null;
        if( a==-1 ) a = 1;
        b %= a;
        break;
      }
    }
    pOut->u.i = b;
    MemSetTypeFlag(pOut, MEM_Int);
  }else{
    double a, b;
    a = sqlite3VdbeRealValue(pIn1);
    b = sqlite3VdbeRealValue(pIn2);
    switch( pOp->opcode ){
      case OP_Add:         b += a;       break;
      case OP_Subtract:    b -= a;       break;
      case OP_Multiply:    b *= a;       break;
      case OP_Divide: {
        /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
        if( a==(double)0 ) goto arithmetic_result_is_null;
        b /= a;
        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;
    MemSetTypeFlag(pOut, MEM_Real);
    if( (flags & MEM_Real)==0 ){
      sqlite3VdbeIntegerAffinity(pOut);
    }
  }
  break;

................................................................................
** See also: AggStep and AggFinal
*/
case OP_Function: {
  int i;
  Mem *pArg;
  sqlite3_context ctx;
  sqlite3_value **apVal;
  int n = pOp->p5;


  apVal = p->apArg;
  assert( apVal || n==0 );

  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=p->nMem+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
  pArg = &p->aMem[pOp->p2];
  for(i=0; i<n; i++, pArg++){
................................................................................
** Store the result in register P3.
** If either input is NULL, the result is NULL.
*/
case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
  i64 a, b;


  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
    sqlite3VdbeMemSetNull(pOut);
    break;
  }
  a = sqlite3VdbeIntValue(pIn2);
  b = sqlite3VdbeIntValue(pIn1);
................................................................................
** only.  The KeyInfo elements are used sequentially.
**
** The comparison is a sort comparison, so NULLs compare equal,
** NULLs are less than numbers, numbers are less than strings,
** and strings are less than blobs.
*/
case OP_Compare: {
  int n = pOp->p3;
  int i, p1, p2;








  const KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
  assert( n>0 );
  assert( pKeyInfo!=0 );
  p1 = pOp->p1;
  assert( p1>0 && p1+n<=p->nMem+1 );
  p2 = pOp->p2;
  assert( p2>0 && p2+n<=p->nMem+1 );
  for(i=0; i<n; i++){
    int idx = aPermute ? aPermute[i] : i;
    CollSeq *pColl;    /* Collating sequence to use on this term */
    int bRev;          /* True for DESCENDING sort order */
    REGISTER_TRACE(p1+idx, &p->aMem[p1+idx]);
    REGISTER_TRACE(p2+idx, &p->aMem[p2+idx]);
    assert( i<pKeyInfo->nField );
    pColl = pKeyInfo->aColl[i];
    bRev = pKeyInfo->aSortOrder[i];
    iCompare = sqlite3MemCompare(&p->aMem[p1+idx], &p->aMem[p2+idx], pColl);
    if( iCompare ){
................................................................................
**
** If either P1 or P2 is nonzero (true) then the result is 1 (true)
** even if the other input is NULL.  A NULL and false or two NULLs
** give a NULL output.
*/
case OP_And:              /* same as TK_AND, in1, in2, out3 */
case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
  int v1, v2;    /* 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */


  if( pIn1->flags & MEM_Null ){
    v1 = 2;
  }else{
    v1 = sqlite3VdbeIntValue(pIn1)!=0;
  }
  if( pIn2->flags & MEM_Null ){
................................................................................
**
** If the column contains fewer than P2 fields, then extract a NULL.  Or,
** if the P4 argument is a P4_MEM use the value of the P4 argument as
** the result.
*/
case OP_Column: {
  int payloadSize;   /* Number of bytes in the record */

  int p1 = pOp->p1;  /* P1 value of the opcode */
  int p2 = pOp->p2;  /* column number to retrieve */
  VdbeCursor *pC = 0;/* The VDBE cursor */
  char *zRec;        /* Pointer to complete record-data */
  BtCursor *pCrsr;   /* The BTree cursor */
  u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
  int nField;        /* number of fields in the record */
  int len;           /* The length of the serialized data for the column */
  int i;             /* Loop counter */
  char *zData;       /* Part of the record being decoded */
  Mem *pDest;        /* Where to write the extracted value */
  Mem sMem;          /* For storing the record being decoded */










  memset(&sMem, 0, sizeof(sMem));
  assert( p1<p->nCursor );
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pDest = &p->aMem[pOp->p3];
  MemSetTypeFlag(pDest, MEM_Null);

  /* This block sets the variable payloadSize to be the total number of
................................................................................
    pCrsr = pC->pCursor;
    if( pC->nullRow ){
      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{
................................................................................
  /* Read and parse the table header.  Store the results of the parse
  ** into the record header cache fields of the cursor.
  */
  aType = pC->aType;
  if( pC->cacheStatus==p->cacheCtr ){
    aOffset = pC->aOffset;
  }else{
    u8 *zIdx;        /* Index into header */
    u8 *zEndHdr;     /* Pointer to first byte after the header */
    int offset;      /* Offset into the data */
    int szHdrSz;     /* Size of the header size field at start of record */
    int avail = 0;   /* Number of bytes of available data */

    assert(aType);

    pC->aOffset = aOffset = &aType[nField];
    pC->payloadSize = payloadSize;
    pC->cacheStatus = p->cacheCtr;

    /* Figure out how many bytes are in the header */
    if( zRec ){
      zData = zRec;
................................................................................

    /* If we have read more header data than was contained in the header,
    ** or if the end of the last field appears to be past the end of the
    ** record, or if the end of the last field appears to be before the end
    ** of the record (when all fields present), then we must be dealing 
    ** with a corrupt database.
    */
    if( zIdx>zEndHdr || offset>payloadSize 
     || (zIdx==zEndHdr && offset!=payloadSize) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto op_column_out;
    }
  }

  /* Get the column information. If aOffset[p2] is non-zero, then 
................................................................................
** Apply affinities to a range of P2 registers starting with P1.
**
** P4 is a string that is P2 characters long. The nth character of the
** string indicates the column affinity that should be used for the nth
** memory cell in the range.
*/
case OP_Affinity: {





  char *zAffinity = pOp->p4.z;
  Mem *pData0 = &p->aMem[pOp->p1];
  Mem *pLast = &pData0[pOp->p2-1];
  Mem *pRec;

  for(pRec=pData0; pRec<=pLast; pRec++){
    ExpandBlob(pRec);
    applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
  }
  break;
}

................................................................................
**
** The mapping from character to affinity is given by the SQLITE_AFF_
** macros defined in sqliteInt.h.
**
** If P4 is NULL then all index fields have the affinity NONE.
*/
case OP_MakeRecord: {
















  /* Assuming the record contains N fields, the record format looks
  ** like this:
  **
  ** ------------------------------------------------------------------------
  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 
  ** ------------------------------------------------------------------------
  **
................................................................................
  ** and so froth.
  **
  ** Each type field is a varint representing the serial type of the 
  ** corresponding data element (see sqlite3VdbeSerialType()). The
  ** hdr-size field is also a varint which is the offset from the beginning
  ** of the record to data0.
  */
  u8 *zNewRecord;        /* A buffer to hold the data for the new record */
  Mem *pRec;             /* The new record */
  u64 nData = 0;         /* Number of bytes of data space */
  int nHdr = 0;          /* Number of bytes of header space */
  i64 nByte = 0;         /* Data space required for this record */
  int nZero = 0;         /* Number of zero bytes at the end of the record */
  int nVarint;           /* Number of bytes in a varint */
  u32 serial_type;       /* Type field */
  Mem *pData0;           /* First field to be combined into the record */
  Mem *pLast;            /* Last field of the record */
  int nField;            /* Number of fields in the record */
  char *zAffinity;       /* The affinity string for the record */
  int file_format;       /* File format to use for encoding */
  int i;                 /* Space used in zNewRecord[] */

  nField = pOp->p1;
  zAffinity = pOp->p4.z;
  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=p->nMem+1 );
  pData0 = &p->aMem[nField];
  nField = pOp->p2;
  pLast = &pData0[nField-1];
  file_format = p->minWriteFileFormat;

  /* Loop through the elements that will make up the record to figure
  ** out how much space is required for the new record.
  */
  for(pRec=pData0; pRec<=pLast; pRec++){
    int len;
    if( zAffinity ){
      applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
    }
    if( pRec->flags&MEM_Zero && pRec->n>0 ){
      sqlite3VdbeMemExpandBlob(pRec);
    }
    serial_type = sqlite3VdbeSerialType(pRec, file_format);
................................................................................
** will be allocated and initialized.
**
** The statement is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Statement: {


  if( db->autoCommit==0 || db->activeVdbeCnt>1 ){
    int i = pOp->p1;
    Btree *pBt;
    assert( i>=0 && i<db->nDb );
    assert( db->aDb[i].pBt!=0 );
    pBt = db->aDb[i].pBt;
    assert( sqlite3BtreeIsInTrans(pBt) );
    assert( (p->btreeMask & (1<<i))!=0 );
    if( p->iStatement==0 ){
      assert( db->nStatement>=0 && db->nSavepoint>=0 );
................................................................................
/* Opcode: Savepoint P1 * * P4 *
**
** Open, release or rollback the savepoint named by parameter P4, depending
** on the value of P1. To open a new savepoint, P1==0. To release (commit) an
** existing savepoint, P1==1, or to rollback an existing savepoint P1==2.
*/
case OP_Savepoint: {









  int p1 = pOp->p1;
  char *zName = pOp->p4.z;         /* Name of savepoint */

  /* Assert that the p1 parameter is valid. Also that if there is no open
  ** transaction, then there cannot be any savepoints. 
  */
  assert( db->pSavepoint==0 || db->autoCommit==0 );
  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
................................................................................
      /* A new savepoint cannot be created if there are active write 
      ** statements (i.e. open read/write incremental blob handles).
      */
      sqlite3SetString(&p->zErrMsg, db, "cannot open savepoint - "
        "SQL statements in progress");
      rc = SQLITE_BUSY;
    }else{
      int nName = sqlite3Strlen30(zName);
      Savepoint *pNew;

      /* Create a new savepoint structure. */
      pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+nName+1);
      if( pNew ){
        pNew->zName = (char *)&pNew[1];
        memcpy(pNew->zName, zName, nName+1);
    
................................................................................
    
        /* Link the new savepoint into the database handle's list. */
        pNew->pNext = db->pSavepoint;
        db->pSavepoint = pNew;
      }
    }
  }else{
    Savepoint *pSavepoint;
    int iSavepoint = 0;

    /* Find the named savepoint. If there is no such savepoint, then an
    ** an error is returned to the user.  */
    for(
      pSavepoint=db->pSavepoint; 
      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
      pSavepoint=pSavepoint->pNext
    ){
      iSavepoint++;
    }
    if( !pSavepoint ){
      sqlite3SetString(&p->zErrMsg, db, "no such savepoint: %s", zName);
      rc = SQLITE_ERROR;
    }else if( 
................................................................................
          db->autoCommit = 0;
          p->rc = rc = SQLITE_BUSY;
          goto vdbe_return;
        }
        db->isTransactionSavepoint = 0;
        rc = p->rc;
      }else{
        int ii;
        iSavepoint = db->nSavepoint - iSavepoint - 1;
        for(ii=0; ii<db->nDb; ii++){
          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
          }
        }
................................................................................
          sqlite3ResetInternalSchema(db, 0);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
        Savepoint *pTmp = db->pSavepoint;
        db->pSavepoint = pTmp->pNext;
        sqlite3DbFree(db, pTmp);
        db->nSavepoint--;
      }

      /* If it is a RELEASE, then destroy the savepoint being operated on too */
      if( p1==SAVEPOINT_RELEASE ){
................................................................................
** back any currently active btree transactions. If there are any active
** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
** there are active writing VMs or active VMs that use shared cache.
**
** This instruction causes the VM to halt.
*/
case OP_AutoCommit: {
  int desiredAutoCommit = pOp->p1;
  int rollback = pOp->p2;
  int turnOnAC = desiredAutoCommit && !db->autoCommit;




  assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
  assert( desiredAutoCommit==1 || rollback==0 );

  assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */

  if( turnOnAC && rollback && db->activeVdbeCnt>1 ){
    /* If this instruction implements a ROLLBACK and other VMs are
    ** still running, and a transaction is active, return an error indicating
    ** that the other VMs must complete first. 
    */
................................................................................
** write transaction must be started before any changes can be made to the
** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
** on the file.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {
  int i = pOp->p1;
  Btree *pBt;


  assert( i>=0 && i<db->nDb );
  assert( (p->btreeMask & (1<<i))!=0 );
  pBt = db->aDb[i].pBt;

  if( pBt ){
    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
    if( rc==SQLITE_BUSY ){
................................................................................
**
** There must be a read-lock on the database (either a transaction
** must be started or there must be an open cursor) before
** executing this instruction.
*/
case OP_ReadCookie: {               /* out2-prerelease */
  int iMeta;
  int iDb = pOp->p1;
  int iCookie = pOp->p3;



  assert( pOp->p3<SQLITE_N_BTREE_META );
  if( iDb<0 ){
    iDb = (-1*(iDb+1));
    iCookie *= -1;
  }
  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pBt!=0 );
................................................................................
** in read/write mode.  For a given table, there can be one or more read-only
** cursors or a single read/write cursor but not both.
**
** See also OpenRead.
*/
case OP_OpenRead:
case OP_OpenWrite: {
  int nField = 0;
  KeyInfo *pKeyInfo = 0;
  int i = pOp->p1;
  int p2 = pOp->p2;
  int iDb = pOp->p3;
  int wrFlag;
  Btree *pX;
  VdbeCursor *pCur;
  Db *pDb;

  





  assert( iDb>=0 && iDb<db->nDb );
  assert( (p->btreeMask & (1<<iDb))!=0 );
  pDb = &db->aDb[iDb];
  pX = pDb->pBt;
  assert( pX!=0 );
  if( pOp->opcode==OP_OpenWrite ){
    wrFlag = 1;
................................................................................
  switch( rc ){
    case SQLITE_BUSY: {
      p->pc = pc;
      p->rc = rc = SQLITE_BUSY;
      goto vdbe_return;
    }
    case SQLITE_OK: {
      int flags = sqlite3BtreeFlags(pCur->pCursor);
      /* Sanity checking.  Only the lower four bits of the flags byte should
      ** be used.  Bit 3 (mask 0x08) is unpredictable.  The lower 3 bits
      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
      ** 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) ){
................................................................................
** This opcode was once called OpenTemp.  But that created
** confusion because the term "temp table", might refer either
** to a TEMP table at the SQL level, or to a table opened by
** this opcode.  Then this opcode was call OpenVirtual.  But
** that created confusion with the whole virtual-table idea.
*/
case OP_OpenEphemeral: {
  int i = pOp->p1;
  VdbeCursor *pCx;
  static const int openFlags = 
      SQLITE_OPEN_READWRITE |
      SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE |
      SQLITE_OPEN_DELETEONCLOSE |
      SQLITE_OPEN_TRANSIENT_DB;


  assert( i>=0 );
  pCx = allocateCursor(p, i, pOp->p2, -1, 1);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, SQLITE_DEFAULT_TEMP_CACHE_SIZE, openFlags,
                           &pCx->pBt);
  if( rc==SQLITE_OK ){
................................................................................
** memory cell containing the row data is not overwritten until the
** pseudo table is closed (or a new row is inserted into it).
**
** P3 is the number of fields in the records that will be stored by
** the pseudo-table.
*/
case OP_OpenPseudo: {
  int i = pOp->p1;
  VdbeCursor *pCx;


  assert( i>=0 );
  pCx = allocateCursor(p, i, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  pCx->ephemPseudoTable = (u8)pOp->p2;
  pCx->isTable = 1;
................................................................................
**
** See also: Found, NotFound, Distinct, SeekGt, SeekGe, SeekLt
*/
case OP_SeekLt:         /* jump, in3 */
case OP_SeekLe:         /* jump, in3 */
case OP_SeekGe:         /* jump, in3 */
case OP_SeekGt: {       /* jump, in3 */
  int i = pOp->p1;


  VdbeCursor *pC;





  assert( i>=0 && i<p->nCursor );
  assert( pOp->p2!=0 );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    int res, oc;
    oc = pOp->opcode;
    pC->nullRow = 0;
    if( pC->isTable ){
      i64 iKey;      /* The rowid we are to seek to */

      /* The input value in P3 might be of any type: integer, real, string,
      ** blob, or NULL.  But it needs to be an integer before we can do
      ** the seek, so covert it. */
      applyNumericAffinity(pIn3);
      iKey = sqlite3VdbeIntValue(pIn3);
      pC->rowidIsValid = 0;

................................................................................
        goto abort_due_to_error;
      }
      if( res==0 ){
        pC->rowidIsValid = 1;
        pC->lastRowid = iKey;
      }
    }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_SeekGt || oc==OP_SeekLe ){
        r.flags = UNPACKED_INCRKEY;
      }else{
................................................................................
** for P1 to move so that it points to the rowid given by P2.
**
** This is actually a deferred seek.  Nothing actually happens until
** the cursor is used to read a record.  That way, if no reads
** occur, no unnecessary I/O happens.
*/
case OP_Seek: {    /* in2 */
  int i = pOp->p1;
  VdbeCursor *pC;


  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    assert( pC->isTable );
    pC->nullRow = 0;
    pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
................................................................................
** to P2.  If an entry does existing, fall through.  The cursor is left
** pointing to the entry that matches.
**
** See also: Found, NotExists, IsUnique
*/
case OP_NotFound:       /* jump, in3 */
case OP_Found: {        /* jump, in3 */
  int i = pOp->p1;
  int alreadyExists = 0;
  VdbeCursor *pC;






  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){
    int res;
    UnpackedRecord *pIdxKey;

    assert( pC->isTable==0 );
    assert( pIn3->flags & MEM_Blob );
    pIdxKey = sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z,
                                      aTempRec, sizeof(aTempRec));
    if( pIdxKey==0 ){
      goto no_mem;
................................................................................
** See also: NotFound, NotExists, Found
*/
case OP_IsUnique: {        /* jump, in3 */
  u16 ii;
  VdbeCursor *pCx;
  BtCursor *pCrsr;
  u16 nField;
  Mem *aMem = &p->aMem[pOp->p4.i];




  /* Assert that the values of parameters P1 and P4 are in range. */
  assert( pOp->p4type==P4_INT32 );
  assert( pOp->p4.i>0 && pOp->p4.i<=p->nMem );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );

  /* Find the index cursor. */
  pCx = p->apCsr[pOp->p1];
................................................................................
      pCrsr = 0;
      break;
    }
  }
  assert( (aMem[nField].flags & MEM_Null)==0 );

  if( pCrsr!=0 ){
    UnpackedRecord r;                  /* B-Tree index search key */
    i64 R;                             /* Rowid stored in register P3 */

    /* Populate the index search key. */
    r.pKeyInfo = pCx->pKeyInfo;
    r.nField = nField + 1;
    r.flags = UNPACKED_PREFIX_SEARCH;
    r.aMem = aMem;

    /* Extract the value of R from register P3. */
................................................................................
** operation assumes the key is an integer and that P1 is a table whereas
** NotFound assumes key is a blob constructed from MakeRecord and
** P1 is an index.
**
** See also: Found, NotFound, IsUnique
*/
case OP_NotExists: {        /* jump, in3 */
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;




  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res = 0;
    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;
................................................................................
** generated record number.  No new record numbers are allowed to be less
** than this value.  When this value reaches its maximum, a SQLITE_FULL
** error is generated.  The P3 register is updated with the generated
** record number.  This P3 mechanism is used to help implement the
** AUTOINCREMENT feature.
*/
case OP_NewRowid: {           /* out2-prerelease */
  int i = pOp->p1;
  i64 v = 0;
  VdbeCursor *pC;










  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor==0 ){
    /* The zero initialization above is all that is needed */
  }else{
    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
................................................................................
    ** random number generator based on the RC4 algorithm.
    **
    ** To promote locality of reference for repetitive inserts, the
    ** first few attempts at choosing a random rowid pick values just a little
    ** larger than the previous rowid.  This has been shown experimentally
    ** to double the speed of the COPY operation.
    */
    int res=0, rx=SQLITE_OK, cnt;
    i64 x;
    cnt = 0;
    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
          BTREE_INTKEY ){
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
................................................................................
            v++;
          }
        }
      }

#ifndef SQLITE_OMIT_AUTOINCREMENT
      if( pOp->p3 ){
        Mem *pMem;
        assert( pOp->p3>0 && pOp->p3<=p->nMem ); /* P3 is a valid memory cell */
        pMem = &p->aMem[pOp->p3];
	REGISTER_TRACE(pOp->p3, pMem);
        sqlite3VdbeMemIntegerify(pMem);
        assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
        if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
          rc = SQLITE_FULL;
................................................................................
** value of register P2 will then change.  Make sure this does not
** cause any problems.)
**
** This instruction only works on tables.  The equivalent instruction
** for indices is OP_IdxInsert.
*/
case OP_Insert: {
  Mem *pData = &p->aMem[pOp->p2];
  Mem *pKey = &p->aMem[pOp->p3];

  i64 iKey;   /* The integer ROWID or key for the record to be inserted */
  int i = pOp->p1;
  VdbeCursor *pC;









  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  assert( pC->pCursor!=0 || pC->pseudoTable );
  assert( pKey->flags & MEM_Int );
  assert( pC->isTable );
  REGISTER_TRACE(pOp->p2, pData);
................................................................................
      if( !pC->pData ) goto no_mem;
      memcpy(pC->pData, pData->z, pC->nData);
      pC->pData[pC->nData] = 0;
      pC->pData[pC->nData+1] = 0;
    }
    pC->nullRow = 0;
  }else{
    int nZero;
    int seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
    if( pData->flags & MEM_Zero ){
      nZero = pData->u.nZero;
    }else{
      nZero = 0;
    }
    sqlite3BtreeSetCachedRowid(pC->pCursor, 0);
    rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
................................................................................
  
  pC->rowidIsValid = 0;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;

  /* Invoke the update-hook if required. */
  if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
    const char *zDb = db->aDb[pC->iDb].zName;
    const char *zTbl = pOp->p4.z;
    int op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
    assert( pC->isTable );
    db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
    assert( pC->iDb>=0 );
  }
  break;
}

................................................................................
**
** If P4 is not NULL, then it is the name of the table that P1 is
** pointing to.  The update hook will be invoked, if it exists.
** If P4 is not NULL then the P1 cursor must have been positioned
** using OP_NotFound prior to invoking this opcode.
*/
case OP_Delete: {
  int i = pOp->p1;
  i64 iKey = 0;
  VdbeCursor *pC;



  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */

  /* If the update-hook will be invoked, set iKey to the rowid of the
  ** row being deleted.
................................................................................
** it is found in the database file.
**
** If the P1 cursor must be pointing to a valid row (not a NULL row)
** of a real table, not a pseudo-table.
*/
case OP_RowKey:
case OP_RowData: {
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  u32 n;



  pOut = &p->aMem[pOp->p2];

  /* Note that RowKey and RowData are really exactly the same instruction */
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC->isTable || pOp->opcode==OP_RowKey );
  assert( pC->isIndex || pOp->opcode==OP_RowData );
................................................................................
  assert( pC->nullRow==0 );
  assert( pC->pseudoTable==0 );
  assert( pC->pCursor!=0 );
  pCrsr = pC->pCursor;
  rc = sqlite3VdbeCursorMoveto(pC);
  if( rc ) goto abort_due_to_error;
  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{
................................................................................
** P1 is currently point to.
**
** P1 can be either an ordinary table or a virtual table.  There used to
** be a separate OP_VRowid opcode for use with virtual tables, but this
** one opcode now works for both table types.
*/
case OP_Rowid: {                 /* out2-prerelease */
  int i = pOp->p1;
  VdbeCursor *pC;
  i64 v;




  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->nullRow ){
    /* Do nothing so that reg[P2] remains NULL */
    break;
  }else if( pC->deferredMoveto ){
    v = pC->movetoTarget;
  }else if( pC->pseudoTable ){
    v = keyToInt(pC->iKey);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  }else if( pC->pVtabCursor ){
    sqlite3_vtab *pVtab;
    const sqlite3_module *pModule;
    pVtab = pC->pVtabCursor->pVtab;
    pModule = pVtab->pModule;
    assert( pModule->xRowid );
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    rc = pModule->xRowid(pC->pVtabCursor, &v);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
................................................................................
/* Opcode: NullRow P1 * * * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always
** write a NULL.
*/
case OP_NullRow: {
  int i = pOp->p1;
  VdbeCursor *pC;


  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->nullRow = 1;
  pC->rowidIsValid = 0;
  if( pC->pCursor ){
    sqlite3BtreeClearCursor(pC->pCursor);
................................................................................
** The next use of the Rowid or Column or Next instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Last: {        /* jump */
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;


  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;
................................................................................
** The next use of the Rowid or Column or Next instruction for P1 
** will refer to the first entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Rewind: {        /* jump */
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  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;
................................................................................
** P3 is a flag that provides a hint to the b-tree layer that this
** insert is likely to be an append.
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_IdxInsert: {        /* in2 */
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;




  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pIn2->flags & MEM_Blob );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    assert( pC->isTable==0 );
    rc = ExpandBlob(pIn2);
    if( rc==SQLITE_OK ){
      int nKey = pIn2->n;
      const char *zKey = pIn2->z;
      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3, 
          ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
      );
      assert( pC->deferredMoveto==0 );
      pC->cacheStatus = CACHE_STALE;
    }
  }
................................................................................
/* Opcode: IdxDelete P1 P2 P3 * *
**
** The content of P3 registers starting at register P2 form
** an unpacked index key. This opcode removes that entry from the 
** index opened by cursor P1.
*/
case OP_IdxDelete: {
  int i = pOp->p1;
  VdbeCursor *pC;
  BtCursor *pCrsr;


  assert( pOp->p3>0 );
  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem+1 );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    UnpackedRecord r;
................................................................................
** Write into register P2 an integer which is the last entry in the record at
** the end of the index key pointed to by cursor P1.  This integer should be
** the rowid of the table entry to which this index entry points.
**
** See also: Rowid, MakeRecord.
*/
case OP_IdxRowid: {              /* out2-prerelease */
  int i = pOp->p1;
  BtCursor *pCrsr;
  VdbeCursor *pC;




  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    i64 rowid;
    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    assert( pC->deferredMoveto==0 );
    assert( pC->isTable==0 );
    if( !pC->nullRow ){
      rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
      if( rc!=SQLITE_OK ){
................................................................................
** Otherwise fall through to the next instruction.
**
** If P5 is non-zero then the key value is increased by an epsilon prior 
** to the comparison.  This makes the opcode work like IdxLE.
*/
case OP_IdxLT:          /* jump, in3 */
case OP_IdxGE: {        /* jump, in3 */
  int i= pOp->p1;
  VdbeCursor *pC;




  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=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;
................................................................................
** If AUTOVACUUM is disabled then a zero is stored in register P2.
**
** See also: Clear
*/
case OP_Destroy: {     /* out2-prerelease */
  int iMoved;
  int iCnt;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Vdbe *pVdbe;


  iCnt = 0;
  for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
    if( pVdbe->magic==VDBE_MAGIC_RUN && pVdbe->inVtabMethod<2 && pVdbe->pc>=0 ){
      iCnt++;
    }
  }
#else
  iCnt = db->activeVdbeCnt;
#endif
  if( iCnt>1 ){
    rc = SQLITE_LOCKED;
    p->errorAction = OE_Abort;
  }else{
    int iDb = pOp->p3;
    assert( iCnt==1 );
    assert( (p->btreeMask & (1<<iDb))!=0 );
    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
    MemSetTypeFlag(pOut, MEM_Int);
    pOut->u.i = iMoved;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( rc==SQLITE_OK && iMoved!=0 ){
................................................................................
** count is incremented by the number of rows in the table being cleared. 
** If P3 is greater than zero, then the value stored in register P3 is
** also incremented by the number of rows in the table being cleared.
**
** See also: Destroy
*/
case OP_Clear: {


  int nChange = 0;
  assert( (p->btreeMask & (1<<pOp->p2))!=0 );
  rc = sqlite3BtreeClearTable(
      db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &nChange : 0)
  );
  if( pOp->p3 ){
    p->nChange += nChange;
    if( pOp->p3>0 ){
................................................................................
** P1>1.  Write the root page number of the new table into
** register P2.
**
** See documentation on OP_CreateTable for additional information.
*/
case OP_CreateIndex:            /* out2-prerelease */
case OP_CreateTable: {          /* out2-prerelease */
  int pgno = 0;
  int flags;
  Db *pDb;


  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  if( pOp->opcode==OP_CreateTable ){
    /* flags = BTREE_INTKEY; */
    flags = BTREE_LEAFDATA|BTREE_INTKEY;
................................................................................
** is false, the SQLITE_MASTER table is only parsed if the rest of the
** schema is already loaded into the symbol table.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {





  int iDb = pOp->p1;
  assert( iDb>=0 && iDb<db->nDb );

  /* If pOp->p2 is 0, then this opcode is being executed to read a
  ** single row, for example the row corresponding to a new index
  ** created by this VDBE, from the sqlite_master table. It only
  ** does this if the corresponding in-memory schema is currently
  ** loaded. Otherwise, the new index definition can be loaded along
................................................................................
  ** will not be reloaded becuase the db->init.busy flag is set. This
  ** can result in a "no such table: sqlite_master" or "malformed
  ** database schema" error being returned to the user.
  */
  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
  sqlite3BtreeEnterAll(db);
  if( pOp->p2 || DbHasProperty(db, iDb, DB_SchemaLoaded) ){
    const char *zMaster = SCHEMA_TABLE(iDb);
    char *zSql;
    InitData initData;
    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
       db->aDb[iDb].zName, zMaster, pOp->p4.z);
    if( zSql==0 ){
................................................................................
/* Opcode: LoadAnalysis P1 * * * *
**
** Read the sqlite_stat1 table for database P1 and load the content
** of that table into the internal index hash table.  This will cause
** the analysis to be used when preparing all subsequent queries.
*/
case OP_LoadAnalysis: {
  int iDb = pOp->p1;
  assert( iDb>=0 && iDb<db->nDb );
  rc = sqlite3AnalysisLoad(db, iDb);
  break;  
}
#endif /* !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)  */

/* Opcode: DropTable P1 * * P4 *
**
** Remove the internal (in-memory) data structures that describe
................................................................................
** (b) when P4==-1 there is no need to insert the value, as it will
** never be tested for, and (c) when a value that is part of set X is
** inserted, there is no need to search to see if the same value was
** previously inserted as part of set X (only if it was previously
** inserted as part of some other set).
*/
case OP_RowSetTest: {                     /* jump, in1, in3 */



  int iSet = pOp->p4.i;
  assert( pIn3->flags&MEM_Int );

  /* If there is anything other than a rowset object in memory cell P1,
  ** delete it now and initialize P1 with an empty rowset
  */
  if( (pIn1->flags & MEM_RowSet)==0 ){
    sqlite3VdbeMemSetRowSet(pIn1);
    if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
  }

  assert( pOp->p4type==P4_INT32 );
  assert( iSet==-1 || iSet>=0 );
  if( iSet ){
    int exists;
    exists = sqlite3RowSetTest(pIn1->u.pRowSet, 
                               (u8)(iSet>=0 ? iSet & 0xf : 0xff),
                               pIn3->u.i);
    if( exists ){
      pc = pOp->p2 - 1;
      break;
    }
................................................................................
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
case OP_ContextPush: {
  int i = p->contextStackTop++;
  Context *pContext;


  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
    p->contextStack = sqlite3DbReallocOrFree(db, p->contextStack,
                                          sizeof(Context)*(i+1));
    if( p->contextStack==0 ) goto no_mem;
................................................................................
/* Opcode: ContextPop * * * 
**
** Restore the Vdbe context to the state it was in when contextPush was last
** executed. The context stores the last insert row id, the last statement
** change count, and the current statement change count.
*/
case OP_ContextPop: {

  Context *pContext = &p->contextStack[--p->contextStackTop];
  assert( p->contextStackTop>=0 );
  db->lastRowid = pContext->lastRowid;
  p->nChange = pContext->nChange;
  break;
}
#endif /* #ifndef SQLITE_OMIT_TRIGGER */

................................................................................
** structure that specifies the function.  Use register
** P3 as the accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.
*/
case OP_AggStep: {
  int n = pOp->p5;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;


  assert( n>=0 );
  pRec = &p->aMem[pOp->p2];
  apVal = p->apArg;
  assert( apVal || n==0 );
  for(i=0; i<n; i++, pRec++){
    apVal[i] = pRec;
    storeTypeInfo(pRec, encoding);
................................................................................
**
** 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&0xFF)==SQLITE_LOCKED ){
    const char *z = pOp->p4.z;
    sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
................................................................................
** xBegin method for that table.
**
** Also, whether or not P4 is set, check that this is not being called from
** within a callback to a virtual table xSync() method. If it is, the error
** code will be set to SQLITE_LOCKED.
*/
case OP_VBegin: {

  sqlite3_vtab *pVtab = pOp->p4.pVtab;
  rc = sqlite3VtabBegin(db, pVtab);
  if( pVtab ){
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
    pVtab->zErrMsg = 0;
  }
  break;
................................................................................
/* Opcode: VOpen P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** P1 is a cursor number.  This opcode opens a cursor to the virtual
** table and stores that cursor in P1.
*/
case OP_VOpen: {
  VdbeCursor *pCur = 0;
  sqlite3_vtab_cursor *pVtabCursor = 0;





  sqlite3_vtab *pVtab = pOp->p4.pVtab;
  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;

  assert(pVtab && pModule);
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xOpen(pVtab, &pVtabCursor);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
................................................................................
**
** A jump is made to P2 if the result set after filtering would be empty.
*/
case OP_VFilter: {   /* jump */
  int nArg;
  int iQuery;
  const sqlite3_module *pModule;
  Mem *pQuery = &p->aMem[pOp->p3];
  Mem *pArgc = &pQuery[1];
  sqlite3_vtab_cursor *pVtabCursor;
  sqlite3_vtab *pVtab;







  VdbeCursor *pCur = p->apCsr[pOp->p1];

  REGISTER_TRACE(pOp->p3, pQuery);
  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++){
      apArg[i] = &pArgc[i+1];
      storeTypeInfo(apArg[i], 0);
    }

    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    sqlite3VtabLock(pVtab);
................................................................................
** jump to instruction P2.  Or, if the virtual table has reached
** the end of its result set, then fall through to the next instruction.
*/
case OP_VNext: {   /* jump */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  int res = 0;


  VdbeCursor *pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xNext );
................................................................................
/* Opcode: VRename P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xRename method. The value
** in register P1 is passed as the zName argument to the xRename method.
*/
case OP_VRename: {



  sqlite3_vtab *pVtab = pOp->p4.pVtab;
  Mem *pName = &p->aMem[pOp->p1];
  assert( pVtab->pModule->xRename );
  REGISTER_TRACE(pOp->p1, pName);

  Stringify(pName, encoding);

  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  sqlite3VtabLock(pVtab);
................................................................................
** a row to delete.
**
** P1 is a boolean flag. If it is set to true and the xUpdate call
** is successful, then the value returned by sqlite3_last_insert_rowid() 
** is set to the value of the rowid for the row just inserted.
*/
case OP_VUpdate: {








  sqlite3_vtab *pVtab = pOp->p4.pVtab;
  sqlite3_module *pModule = (sqlite3_module *)pVtab->pModule;
  int nArg = pOp->p2;
  assert( pOp->p4type==P4_VTAB );
  if( pModule->xUpdate==0 ){
    sqlite3SetString(&p->zErrMsg, db, "read-only table");
    rc = SQLITE_ERROR;
  }else{
    int i;
    sqlite_int64 rowid;
    Mem **apArg = p->apArg;
    Mem *pX = &p->aMem[pOp->p3];
    for(i=0; i<nArg; i++){
      storeTypeInfo(pX, 0);
      apArg[i] = pX;
      pX++;
    }
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    sqlite3VtabLock(pVtab);
................................................................................

#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
/* Opcode: Pagecount P1 P2 * * *
**
** Write the current number of pages in database P1 to memory cell P2.
*/
case OP_Pagecount: {            /* out2-prerelease */
  int p1 = pOp->p1; 
  int nPage;
  Pager *pPager = sqlite3BtreePager(db->aDb[p1].pBt);



  rc = sqlite3PagerPagecount(pPager, &nPage);
  if( rc==SQLITE_OK ){
    pOut->flags = MEM_Int;
    pOut->u.i = nPage;
  }
  break;
}
................................................................................
#ifndef SQLITE_OMIT_TRACE
/* Opcode: Trace * * * P4 *
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
*/
case OP_Trace: {


  char *zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
  if( zTrace ){
    if( db->xTrace ){
      db->xTrace(db->pTraceArg, zTrace);
    }
#ifdef SQLITE_DEBUG
    if( (db->flags & SQLITE_SqlTrace)!=0 ){
      sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);







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39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
...
560
561
562
563
564
565
566
567


568
569
570
571
572
573
574
...
976
977
978
979
980
981
982
983
984
985
986
987
988
989

990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
....
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
....
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232

1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261

1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
....
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
....
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
....
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791


1792
1793
1794
1795
1796
1797
1798
....
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
....
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
....
2056
2057
2058
2059
2060
2061
2062

2063
2064
2065
2066
2067
2068
2069
....
2091
2092
2093
2094
2095
2096
2097






2098
2099
2100
2101
2102
2103
2104
2105
2106
....
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
....
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253


2254
2255
2256
2257
2258
2259
2260
....
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
....
2304
2305
2306
2307
2308
2309
2310


2311
2312
2313
2314









2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326

2327
2328
2329
2330
2331
2332
2333
....
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439

2440
2441
2442
2443
2444
2445
2446
....
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
....
2484
2485
2486
2487
2488
2489
2490
2491

2492
2493
2494
2495
2496
2497
2498
....
2507
2508
2509
2510
2511
2512
2513

2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
....
2551
2552
2553
2554
2555
2556
2557

2558
2559
2560
2561
2562
2563
2564
....
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
....
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613

2614
2615
2616
2617
2618
2619
2620
....
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
....
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
....
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
....
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
....
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
....
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
....
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179

3180
3181
3182


3183
3184
3185
3186
3187
3188
3189
....
3233
3234
3235
3236
3237
3238
3239

3240
3241
3242
3243
3244
3245
3246
3247
....
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
....
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368


3369
3370
3371
3372
3373
3374
3375
....
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
....
3449
3450
3451
3452
3453
3454
3455



3456
3457
3458
3459
3460
3461
3462
....
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504

3505
3506
3507
3508
3509
3510
3511
....
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
....
3605
3606
3607
3608
3609
3610
3611


3612
3613
3614
3615
3616
3617
3618
....
3646
3647
3648
3649
3650
3651
3652

3653
3654
3655
3656
3657
3658
3659
....
3722
3723
3724
3725
3726
3727
3728
3729
3730

3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
....
3776
3777
3778
3779
3780
3781
3782

3783
3784
3785
3786
3787
3788
3789
3790
....
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
....
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
....
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
....
3922
3923
3924
3925
3926
3927
3928

3929
3930
3931
3932
3933
3934
3935
....
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984


3985
3986
3987
3988
3989
3990
3991
....
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
....
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
....
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
....
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
....
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
....
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256

4257
4258
4259
4260

4261
4262
4263
4264
4265
4266
4267
....
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313


4314
4315
4316
4317
4318
4319
4320
....
4355
4356
4357
4358
4359
4360
4361

4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
....
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
....
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
....
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
....
4511
4512
4513
4514
4515
4516
4517
4518


4519
4520
4521
4522
4523
4524
4525
....
4548
4549
4550
4551
4552
4553
4554
4555

4556
4557
4558
4559
4560
4561
4562
4563
....
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750

4751
4752
4753
4754
4755
4756
4757
....
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
....
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
....
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
....
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
....
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
....
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107

5108
5109
5110
5111
5112
5113
5114
....
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
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5167

5168
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5175
5176
5177
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5179
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5181

5182
5183
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5186
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5188
5189
....
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
....
5322
5323
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5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
....
5370
5371
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5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392


5393
5394
5395
5396
5397
5398
5399
5400
5401
....
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
....
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
**
** 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 1.844 2009/06/02 15:21:42 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
................................................................................
#ifdef VDBE_PROFILE
  u64 start;                 /* CPU clock count at start of opcode */
  int origPc;                /* Program counter at start of opcode */
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  int nProgressOps = 0;      /* Opcodes executed since progress callback. */
#endif
  /*** INSERT STACK UNION HERE ***/



  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  assert( db->magic==SQLITE_MAGIC_BUSY );
  sqlite3VdbeMutexArrayEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
................................................................................
** Transfer the values of bound parameters P1..P1+P3-1 into registers
** P2..P2+P3-1.
**
** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {
  int p1;          /* Variable to copy from */
  int p2;          /* Register to copy to */
  int n;           /* Number of values left to copy */
  Mem *pVar;       /* Value being transferred */

  p1 = pOp->p1 - 1;
  p2 = pOp->p2;

  n = pOp->p3;
  assert( p1>=0 && p1+n<=p->nVar );
  assert( p2>=1 && p2+n-1<=p->nMem );
  assert( pOp->p4.z==0 || pOp->p3==1 );

  while( n-- > 0 ){
    pVar = &p->aVar[p1++];
    if( sqlite3VdbeMemTooBig(pVar) ){
      goto too_big;
    }
    pOut = &p->aMem[p2++];
    sqlite3VdbeMemReleaseExternal(pOut);
    pOut->flags = MEM_Null;
    sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
    UPDATE_MAX_BLOBSIZE(pOut);
  }
  break;
}
................................................................................
**
** Move the values in register P1..P1+P3-1 over into
** registers P2..P2+P3-1.  Registers P1..P1+P1-1 are
** left holding a NULL.  It is an error for register ranges
** P1..P1+P3-1 and P2..P2+P3-1 to overlap.
*/
case OP_Move: {
  char *zMalloc;   /* Holding variable for allocated memory */
  int n;           /* Number of registers left to copy */
  int p1;          /* Register to copy from */
  int p2;          /* Register to copy to */

  n = pOp->p3;
  p1 = pOp->p1;
  p2 = pOp->p2;
  assert( n>0 && p1>0 && p2>0 );
  assert( p1+n<=p2 || p2+n<=p1 );

  pIn1 = &p->aMem[p1];
  pOut = &p->aMem[p2];
  while( n-- ){
    assert( pOut<=&p->aMem[p->nMem] );
................................................................................
** If either operand is NULL, the result is NULL.
*/
case OP_Add:                   /* same as TK_PLUS, in1, in2, out3 */
case OP_Subtract:              /* same as TK_MINUS, in1, in2, out3 */
case OP_Multiply:              /* same as TK_STAR, in1, in2, out3 */
case OP_Divide:                /* same as TK_SLASH, in1, in2, out3 */
case OP_Remainder: {           /* same as TK_REM, in1, in2, out3 */
  int flags;      /* Combined MEM_* flags from both inputs */
  i64 iA;         /* Integer value of left operand */
  i64 iB;         /* Integer value of right operand */
  double rA;      /* Real value of left operand */
  double rB;      /* Real value of right operand */

  applyNumericAffinity(pIn1);
  applyNumericAffinity(pIn2);
  flags = pIn1->flags | pIn2->flags;
  if( (flags & MEM_Null)!=0 ) goto arithmetic_result_is_null;
  if( (pIn1->flags & pIn2->flags & MEM_Int)==MEM_Int ){

    iA = pIn1->u.i;
    iB = pIn2->u.i;
    switch( pOp->opcode ){
      case OP_Add:         iB += iA;       break;
      case OP_Subtract:    iB -= iA;       break;
      case OP_Multiply:    iB *= iA;       break;
      case OP_Divide: {
        if( iA==0 ) goto arithmetic_result_is_null;
        /* Dividing the largest possible negative 64-bit integer (1<<63) by 
        ** -1 returns an integer too large to store in a 64-bit data-type. On
        ** some architectures, the value overflows to (1<<63). On others,
        ** a SIGFPE is issued. The following statement normalizes this
        ** behavior so that all architectures behave as if integer 
        ** overflow occurred.
        */
        if( iA==-1 && iB==SMALLEST_INT64 ) iA = 1;
        iB /= iA;
        break;
      }
      default: {
        if( iA==0 ) goto arithmetic_result_is_null;
        if( iA==-1 ) iA = 1;
        iB %= iA;
        break;
      }
    }
    pOut->u.i = iB;
    MemSetTypeFlag(pOut, MEM_Int);
  }else{

    rA = sqlite3VdbeRealValue(pIn1);
    rB = sqlite3VdbeRealValue(pIn2);
    switch( pOp->opcode ){
      case OP_Add:         rB += rA;       break;
      case OP_Subtract:    rB -= rA;       break;
      case OP_Multiply:    rB *= rA;       break;
      case OP_Divide: {
        /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
        if( rA==(double)0 ) goto arithmetic_result_is_null;
        rB /= rA;
        break;
      }
      default: {
        iA = rA;
        iB = rB;
        if( iA==0 ) goto arithmetic_result_is_null;
        if( iA==-1 ) iA = 1;
        rB = (double)(iB % iA);
        break;
      }
    }
    if( sqlite3IsNaN(rB) ){
      goto arithmetic_result_is_null;
    }
    pOut->r = rB;
    MemSetTypeFlag(pOut, MEM_Real);
    if( (flags & MEM_Real)==0 ){
      sqlite3VdbeIntegerAffinity(pOut);
    }
  }
  break;

................................................................................
** See also: AggStep and AggFinal
*/
case OP_Function: {
  int i;
  Mem *pArg;
  sqlite3_context ctx;
  sqlite3_value **apVal;
  int n;

  n = pOp->p5;
  apVal = p->apArg;
  assert( apVal || n==0 );

  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=p->nMem+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
  pArg = &p->aMem[pOp->p2];
  for(i=0; i<n; i++, pArg++){
................................................................................
** Store the result in register P3.
** If either input is NULL, the result is NULL.
*/
case OP_BitAnd:                 /* same as TK_BITAND, in1, in2, out3 */
case OP_BitOr:                  /* same as TK_BITOR, in1, in2, out3 */
case OP_ShiftLeft:              /* same as TK_LSHIFT, in1, in2, out3 */
case OP_ShiftRight: {           /* same as TK_RSHIFT, in1, in2, out3 */
  i64 a;
  i64 b;

  if( (pIn1->flags | pIn2->flags) & MEM_Null ){
    sqlite3VdbeMemSetNull(pOut);
    break;
  }
  a = sqlite3VdbeIntValue(pIn2);
  b = sqlite3VdbeIntValue(pIn1);
................................................................................
** only.  The KeyInfo elements are used sequentially.
**
** The comparison is a sort comparison, so NULLs compare equal,
** NULLs are less than numbers, numbers are less than strings,
** and strings are less than blobs.
*/
case OP_Compare: {
  int n;
  int i;
  int p1;
  int p2;
  const KeyInfo *pKeyInfo;
  int idx;
  CollSeq *pColl;    /* Collating sequence to use on this term */
  int bRev;          /* True for DESCENDING sort order */

  n = pOp->p3;
  pKeyInfo = pOp->p4.pKeyInfo;
  assert( n>0 );
  assert( pKeyInfo!=0 );
  p1 = pOp->p1;
  assert( p1>0 && p1+n<=p->nMem+1 );
  p2 = pOp->p2;
  assert( p2>0 && p2+n<=p->nMem+1 );
  for(i=0; i<n; i++){
    idx = aPermute ? aPermute[i] : i;


    REGISTER_TRACE(p1+idx, &p->aMem[p1+idx]);
    REGISTER_TRACE(p2+idx, &p->aMem[p2+idx]);
    assert( i<pKeyInfo->nField );
    pColl = pKeyInfo->aColl[i];
    bRev = pKeyInfo->aSortOrder[i];
    iCompare = sqlite3MemCompare(&p->aMem[p1+idx], &p->aMem[p2+idx], pColl);
    if( iCompare ){
................................................................................
**
** If either P1 or P2 is nonzero (true) then the result is 1 (true)
** even if the other input is NULL.  A NULL and false or two NULLs
** give a NULL output.
*/
case OP_And:              /* same as TK_AND, in1, in2, out3 */
case OP_Or: {             /* same as TK_OR, in1, in2, out3 */
  int v1;    /* Left operand:  0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */
  int v2;    /* Right operand: 0==FALSE, 1==TRUE, 2==UNKNOWN or NULL */

  if( pIn1->flags & MEM_Null ){
    v1 = 2;
  }else{
    v1 = sqlite3VdbeIntValue(pIn1)!=0;
  }
  if( pIn2->flags & MEM_Null ){
................................................................................
**
** If the column contains fewer than P2 fields, then extract a NULL.  Or,
** if the P4 argument is a P4_MEM use the value of the P4 argument as
** the result.
*/
case OP_Column: {
  int payloadSize;   /* Number of bytes in the record */
  i64 payloadSize64; /* Number of bytes in the record */
  int p1;            /* P1 value of the opcode */
  int p2;            /* column number to retrieve */
  VdbeCursor *pC;    /* The VDBE cursor */
  char *zRec;        /* Pointer to complete record-data */
  BtCursor *pCrsr;   /* The BTree cursor */
  u32 *aType;        /* aType[i] holds the numeric type of the i-th column */
  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
  int nField;        /* number of fields in the record */
  int len;           /* The length of the serialized data for the column */
  int i;             /* Loop counter */
  char *zData;       /* Part of the record being decoded */
  Mem *pDest;        /* Where to write the extracted value */
  Mem sMem;          /* For storing the record being decoded */
  u8 *zIdx;         /* Index into header */
  u8 *zEndHdr;      /* Pointer to first byte after the header */
  int offset;       /* Offset into the data */
  int szHdrSz;      /* Size of the header size field at start of record */
  int avail;        /* Number of bytes of available data */


  p1 = pOp->p1;
  p2 = pOp->p2;
  pC = 0;
  memset(&sMem, 0, sizeof(sMem));
  assert( p1<p->nCursor );
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pDest = &p->aMem[pOp->p3];
  MemSetTypeFlag(pDest, MEM_Null);

  /* This block sets the variable payloadSize to be the total number of
................................................................................
    pCrsr = pC->pCursor;
    if( pC->nullRow ){
      payloadSize = 0;
    }else if( pC->cacheStatus==p->cacheCtr ){
      payloadSize = pC->payloadSize;
      zRec = (char*)pC->aRow;
    }else if( pC->isIndex ){

      sqlite3BtreeKeySize(pCrsr, &payloadSize64);
      payloadSize = (int)payloadSize64;
    }else{
      sqlite3BtreeDataSize(pCrsr, (u32 *)&payloadSize);
    }
    nField = pC->nField;
  }else{
................................................................................
  /* Read and parse the table header.  Store the results of the parse
  ** into the record header cache fields of the cursor.
  */
  aType = pC->aType;
  if( pC->cacheStatus==p->cacheCtr ){
    aOffset = pC->aOffset;
  }else{






    assert(aType);
    avail = 0;
    pC->aOffset = aOffset = &aType[nField];
    pC->payloadSize = payloadSize;
    pC->cacheStatus = p->cacheCtr;

    /* Figure out how many bytes are in the header */
    if( zRec ){
      zData = zRec;
................................................................................

    /* If we have read more header data than was contained in the header,
    ** or if the end of the last field appears to be past the end of the
    ** record, or if the end of the last field appears to be before the end
    ** of the record (when all fields present), then we must be dealing 
    ** with a corrupt database.
    */
    if( (zIdx > zEndHdr)|| (offset > payloadSize)
     || (zIdx==zEndHdr && offset!=payloadSize) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto op_column_out;
    }
  }

  /* Get the column information. If aOffset[p2] is non-zero, then 
................................................................................
** Apply affinities to a range of P2 registers starting with P1.
**
** P4 is a string that is P2 characters long. The nth character of the
** string indicates the column affinity that should be used for the nth
** memory cell in the range.
*/
case OP_Affinity: {
  char *zAffinity;   /* The affinity to be applied */
  Mem *pData0;       /* First register to which to apply affinity */
  Mem *pLast;        /* Last register to which to apply affinity */
  Mem *pRec;         /* Current register */

  zAffinity = pOp->p4.z;
  pData0 = &p->aMem[pOp->p1];
  pLast = &pData0[pOp->p2-1];


  for(pRec=pData0; pRec<=pLast; pRec++){
    ExpandBlob(pRec);
    applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
  }
  break;
}

................................................................................
**
** The mapping from character to affinity is given by the SQLITE_AFF_
** macros defined in sqliteInt.h.
**
** If P4 is NULL then all index fields have the affinity NONE.
*/
case OP_MakeRecord: {
  u8 *zNewRecord;        /* A buffer to hold the data for the new record */
  Mem *pRec;             /* The new record */
  u64 nData;             /* Number of bytes of data space */
  int nHdr;              /* Number of bytes of header space */
  i64 nByte;             /* Data space required for this record */
  int nZero;             /* Number of zero bytes at the end of the record */
  int nVarint;           /* Number of bytes in a varint */
  u32 serial_type;       /* Type field */
  Mem *pData0;           /* First field to be combined into the record */
  Mem *pLast;            /* Last field of the record */
  int nField;            /* Number of fields in the record */
  char *zAffinity;       /* The affinity string for the record */
  int file_format;       /* File format to use for encoding */
  int i;                 /* Space used in zNewRecord[] */
  int len;               /* Length of a field */

  /* Assuming the record contains N fields, the record format looks
  ** like this:
  **
  ** ------------------------------------------------------------------------
  ** | hdr-size | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 
  ** ------------------------------------------------------------------------
  **
................................................................................
  ** and so froth.
  **
  ** Each type field is a varint representing the serial type of the 
  ** corresponding data element (see sqlite3VdbeSerialType()). The
  ** hdr-size field is also a varint which is the offset from the beginning
  ** of the record to data0.
  */


  nData = 0;         /* Number of bytes of data space */
  nHdr = 0;          /* Number of bytes of header space */
  nByte = 0;         /* Data space required for this record */
  nZero = 0;         /* Number of zero bytes at the end of the record */









  nField = pOp->p1;
  zAffinity = pOp->p4.z;
  assert( nField>0 && pOp->p2>0 && pOp->p2+nField<=p->nMem+1 );
  pData0 = &p->aMem[nField];
  nField = pOp->p2;
  pLast = &pData0[nField-1];
  file_format = p->minWriteFileFormat;

  /* Loop through the elements that will make up the record to figure
  ** out how much space is required for the new record.
  */
  for(pRec=pData0; pRec<=pLast; pRec++){

    if( zAffinity ){
      applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
    }
    if( pRec->flags&MEM_Zero && pRec->n>0 ){
      sqlite3VdbeMemExpandBlob(pRec);
    }
    serial_type = sqlite3VdbeSerialType(pRec, file_format);
................................................................................
** will be allocated and initialized.
**
** The statement is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Statement: {
  int i;
  Btree *pBt;
  if( db->autoCommit==0 || db->activeVdbeCnt>1 ){
    i = pOp->p1;

    assert( i>=0 && i<db->nDb );
    assert( db->aDb[i].pBt!=0 );
    pBt = db->aDb[i].pBt;
    assert( sqlite3BtreeIsInTrans(pBt) );
    assert( (p->btreeMask & (1<<i))!=0 );
    if( p->iStatement==0 ){
      assert( db->nStatement>=0 && db->nSavepoint>=0 );
................................................................................
/* Opcode: Savepoint P1 * * P4 *
**
** Open, release or rollback the savepoint named by parameter P4, depending
** on the value of P1. To open a new savepoint, P1==0. To release (commit) an
** existing savepoint, P1==1, or to rollback an existing savepoint P1==2.
*/
case OP_Savepoint: {
  int p1;                         /* Value of P1 operand */
  char *zName;                    /* Name of savepoint */
  int nName;
  Savepoint *pNew;
  Savepoint *pSavepoint;
  Savepoint *pTmp;
  int iSavepoint;
  int ii;

  p1 = pOp->p1;
  zName = pOp->p4.z;

  /* Assert that the p1 parameter is valid. Also that if there is no open
  ** transaction, then there cannot be any savepoints. 
  */
  assert( db->pSavepoint==0 || db->autoCommit==0 );
  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
................................................................................
      /* A new savepoint cannot be created if there are active write 
      ** statements (i.e. open read/write incremental blob handles).
      */
      sqlite3SetString(&p->zErrMsg, db, "cannot open savepoint - "
        "SQL statements in progress");
      rc = SQLITE_BUSY;
    }else{
      nName = sqlite3Strlen30(zName);


      /* Create a new savepoint structure. */
      pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+nName+1);
      if( pNew ){
        pNew->zName = (char *)&pNew[1];
        memcpy(pNew->zName, zName, nName+1);
    
................................................................................
    
        /* Link the new savepoint into the database handle's list. */
        pNew->pNext = db->pSavepoint;
        db->pSavepoint = pNew;
      }
    }
  }else{

    iSavepoint = 0;

    /* Find the named savepoint. If there is no such savepoint, then an
    ** an error is returned to the user.  */
    for(
      pSavepoint = db->pSavepoint; 
      pSavepoint && sqlite3StrICmp(pSavepoint->zName, zName);
      pSavepoint = pSavepoint->pNext
    ){
      iSavepoint++;
    }
    if( !pSavepoint ){
      sqlite3SetString(&p->zErrMsg, db, "no such savepoint: %s", zName);
      rc = SQLITE_ERROR;
    }else if( 
................................................................................
          db->autoCommit = 0;
          p->rc = rc = SQLITE_BUSY;
          goto vdbe_return;
        }
        db->isTransactionSavepoint = 0;
        rc = p->rc;
      }else{

        iSavepoint = db->nSavepoint - iSavepoint - 1;
        for(ii=0; ii<db->nDb; ii++){
          rc = sqlite3BtreeSavepoint(db->aDb[ii].pBt, p1, iSavepoint);
          if( rc!=SQLITE_OK ){
            goto abort_due_to_error;
          }
        }
................................................................................
          sqlite3ResetInternalSchema(db, 0);
        }
      }
  
      /* Regardless of whether this is a RELEASE or ROLLBACK, destroy all 
      ** savepoints nested inside of the savepoint being operated on. */
      while( db->pSavepoint!=pSavepoint ){
        pTmp = db->pSavepoint;
        db->pSavepoint = pTmp->pNext;
        sqlite3DbFree(db, pTmp);
        db->nSavepoint--;
      }

      /* If it is a RELEASE, then destroy the savepoint being operated on too */
      if( p1==SAVEPOINT_RELEASE ){
................................................................................
** back any currently active btree transactions. If there are any active
** VMs (apart from this one), then a ROLLBACK fails.  A COMMIT fails if
** there are active writing VMs or active VMs that use shared cache.
**
** This instruction causes the VM to halt.
*/
case OP_AutoCommit: {
  int desiredAutoCommit;
  int rollback;
  int turnOnAC;

  desiredAutoCommit = pOp->p1;
  rollback = pOp->p2;
  turnOnAC = desiredAutoCommit && !db->autoCommit;
  assert( desiredAutoCommit==1 || desiredAutoCommit==0 );
  assert( desiredAutoCommit==1 || rollback==0 );

  assert( db->activeVdbeCnt>0 );  /* At least this one VM is active */

  if( turnOnAC && rollback && db->activeVdbeCnt>1 ){
    /* If this instruction implements a ROLLBACK and other VMs are
    ** still running, and a transaction is active, return an error indicating
    ** that the other VMs must complete first. 
    */
................................................................................
** write transaction must be started before any changes can be made to the
** database.  If P2 is 2 or greater then an EXCLUSIVE lock is also obtained
** on the file.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {
  int i;
  Btree *pBt;

  i = pOp->p1;
  assert( i>=0 && i<db->nDb );
  assert( (p->btreeMask & (1<<i))!=0 );
  pBt = db->aDb[i].pBt;

  if( pBt ){
    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
    if( rc==SQLITE_BUSY ){
................................................................................
**
** There must be a read-lock on the database (either a transaction
** must be started or there must be an open cursor) before
** executing this instruction.
*/
case OP_ReadCookie: {               /* out2-prerelease */
  int iMeta;
  int iDb;
  int iCookie;

  iDb = pOp->p1;
  iCookie = pOp->p3;
  assert( pOp->p3<SQLITE_N_BTREE_META );
  if( iDb<0 ){
    iDb = (-1*(iDb+1));
    iCookie *= -1;
  }
  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pBt!=0 );
................................................................................
** in read/write mode.  For a given table, there can be one or more read-only
** cursors or a single read/write cursor but not both.
**
** See also OpenRead.
*/
case OP_OpenRead:
case OP_OpenWrite: {
  int nField;
  KeyInfo *pKeyInfo;
  int i;
  int p2;
  int iDb;
  int wrFlag;
  Btree *pX;
  VdbeCursor *pCur;
  Db *pDb;
  int flags;

  nField = 0;
  pKeyInfo = 0;
  i = pOp->p1;
  p2 = pOp->p2;
  iDb = pOp->p3;
  assert( iDb>=0 && iDb<db->nDb );
  assert( (p->btreeMask & (1<<iDb))!=0 );
  pDb = &db->aDb[iDb];
  pX = pDb->pBt;
  assert( pX!=0 );
  if( pOp->opcode==OP_OpenWrite ){
    wrFlag = 1;
................................................................................
  switch( rc ){
    case SQLITE_BUSY: {
      p->pc = pc;
      p->rc = rc = SQLITE_BUSY;
      goto vdbe_return;
    }
    case SQLITE_OK: {
      flags = sqlite3BtreeFlags(pCur->pCursor);
      /* Sanity checking.  Only the lower four bits of the flags byte should
      ** be used.  Bit 3 (mask 0x08) is unpredictable.  The lower 3 bits
      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
      ** 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) ){
................................................................................
** This opcode was once called OpenTemp.  But that created
** confusion because the term "temp table", might refer either
** to a TEMP table at the SQL level, or to a table opened by
** this opcode.  Then this opcode was call OpenVirtual.  But
** that created confusion with the whole virtual-table idea.
*/
case OP_OpenEphemeral: {
  int i;
  VdbeCursor *pCx;
  static const int openFlags = 
      SQLITE_OPEN_READWRITE |
      SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE |
      SQLITE_OPEN_DELETEONCLOSE |
      SQLITE_OPEN_TRANSIENT_DB;

  i = pOp->p1;
  assert( i>=0 );
  pCx = allocateCursor(p, i, pOp->p2, -1, 1);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, SQLITE_DEFAULT_TEMP_CACHE_SIZE, openFlags,
                           &pCx->pBt);
  if( rc==SQLITE_OK ){
................................................................................
** memory cell containing the row data is not overwritten until the
** pseudo table is closed (or a new row is inserted into it).
**
** P3 is the number of fields in the records that will be stored by
** the pseudo-table.
*/
case OP_OpenPseudo: {
  int i;
  VdbeCursor *pCx;

  i = pOp->p1;
  assert( i>=0 );
  pCx = allocateCursor(p, i, pOp->p3, -1, 0);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->pseudoTable = 1;
  pCx->ephemPseudoTable = (u8)pOp->p2;
  pCx->isTable = 1;
................................................................................
**
** See also: Found, NotFound, Distinct, SeekGt, SeekGe, SeekLt
*/
case OP_SeekLt:         /* jump, in3 */
case OP_SeekLe:         /* jump, in3 */
case OP_SeekGe:         /* jump, in3 */
case OP_SeekGt: {       /* jump, in3 */
  int i;
  int res;
  int oc;
  VdbeCursor *pC;
  UnpackedRecord r;
  int nField;
  i64 iKey;      /* The rowid we are to seek to */

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  assert( pOp->p2!=0 );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){

    oc = pOp->opcode;
    pC->nullRow = 0;
    if( pC->isTable ){


      /* The input value in P3 might be of any type: integer, real, string,
      ** blob, or NULL.  But it needs to be an integer before we can do
      ** the seek, so covert it. */
      applyNumericAffinity(pIn3);
      iKey = sqlite3VdbeIntValue(pIn3);
      pC->rowidIsValid = 0;

................................................................................
        goto abort_due_to_error;
      }
      if( res==0 ){
        pC->rowidIsValid = 1;
        pC->lastRowid = iKey;
      }
    }else{

      nField = pOp->p4.i;
      assert( pOp->p4type==P4_INT32 );
      assert( nField>0 );
      r.pKeyInfo = pC->pKeyInfo;
      r.nField = (u16)nField;
      if( oc==OP_SeekGt || oc==OP_SeekLe ){
        r.flags = UNPACKED_INCRKEY;
      }else{
................................................................................
** for P1 to move so that it points to the rowid given by P2.
**
** This is actually a deferred seek.  Nothing actually happens until
** the cursor is used to read a record.  That way, if no reads
** occur, no unnecessary I/O happens.
*/
case OP_Seek: {    /* in2 */
  int i;
  VdbeCursor *pC;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->pCursor!=0 ){
    assert( pC->isTable );
    pC->nullRow = 0;
    pC->movetoTarget = sqlite3VdbeIntValue(pIn2);
................................................................................
** to P2.  If an entry does existing, fall through.  The cursor is left
** pointing to the entry that matches.
**
** See also: Found, NotExists, IsUnique
*/
case OP_NotFound:       /* jump, in3 */
case OP_Found: {        /* jump, in3 */
  int i;
  int alreadyExists;
  VdbeCursor *pC;
  int res;
  UnpackedRecord *pIdxKey;
  char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];

  i = pOp->p1;
  alreadyExists = 0;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){



    assert( pC->isTable==0 );
    assert( pIn3->flags & MEM_Blob );
    pIdxKey = sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z,
                                      aTempRec, sizeof(aTempRec));
    if( pIdxKey==0 ){
      goto no_mem;
................................................................................
** See also: NotFound, NotExists, Found
*/
case OP_IsUnique: {        /* jump, in3 */
  u16 ii;
  VdbeCursor *pCx;
  BtCursor *pCrsr;
  u16 nField;
  Mem *aMem;
  UnpackedRecord r;                  /* B-Tree index search key */
  i64 R;                             /* Rowid stored in register P3 */

  aMem = &p->aMem[pOp->p4.i];
  /* Assert that the values of parameters P1 and P4 are in range. */
  assert( pOp->p4type==P4_INT32 );
  assert( pOp->p4.i>0 && pOp->p4.i<=p->nMem );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );

  /* Find the index cursor. */
  pCx = p->apCsr[pOp->p1];
................................................................................
      pCrsr = 0;
      break;
    }
  }
  assert( (aMem[nField].flags & MEM_Null)==0 );

  if( pCrsr!=0 ){



    /* Populate the index search key. */
    r.pKeyInfo = pCx->pKeyInfo;
    r.nField = nField + 1;
    r.flags = UNPACKED_PREFIX_SEARCH;
    r.aMem = aMem;

    /* Extract the value of R from register P3. */
................................................................................
** operation assumes the key is an integer and that P1 is a table whereas
** NotFound assumes key is a blob constructed from MakeRecord and
** P1 is an index.
**
** See also: Found, NotFound, IsUnique
*/
case OP_NotExists: {        /* jump, in3 */
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;
  u64 iKey;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    res = 0;

    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;
................................................................................
** generated record number.  No new record numbers are allowed to be less
** than this value.  When this value reaches its maximum, a SQLITE_FULL
** error is generated.  The P3 register is updated with the generated
** record number.  This P3 mechanism is used to help implement the
** AUTOINCREMENT feature.
*/
case OP_NewRowid: {           /* out2-prerelease */
  int i;
  i64 v;
  VdbeCursor *pC;
  int res;
  int rx;
  int cnt;
  i64 x;
  Mem *pMem;

  i = pOp->p1;
  v = 0;
  res = 0;
  rx = SQLITE_OK;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor==0 ){
    /* The zero initialization above is all that is needed */
  }else{
    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
................................................................................
    ** random number generator based on the RC4 algorithm.
    **
    ** To promote locality of reference for repetitive inserts, the
    ** first few attempts at choosing a random rowid pick values just a little
    ** larger than the previous rowid.  This has been shown experimentally
    ** to double the speed of the COPY operation.
    */


    cnt = 0;
    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
          BTREE_INTKEY ){
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
................................................................................
            v++;
          }
        }
      }

#ifndef SQLITE_OMIT_AUTOINCREMENT
      if( pOp->p3 ){

        assert( pOp->p3>0 && pOp->p3<=p->nMem ); /* P3 is a valid memory cell */
        pMem = &p->aMem[pOp->p3];
	REGISTER_TRACE(pOp->p3, pMem);
        sqlite3VdbeMemIntegerify(pMem);
        assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
        if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
          rc = SQLITE_FULL;
................................................................................
** value of register P2 will then change.  Make sure this does not
** cause any problems.)
**
** This instruction only works on tables.  The equivalent instruction
** for indices is OP_IdxInsert.
*/
case OP_Insert: {
  Mem *pData;
  Mem *pKey;

  i64 iKey;   /* The integer ROWID or key for the record to be inserted */
  int i;
  VdbeCursor *pC;
  int nZero;
  int seekResult;
  const char *zDb;
  const char *zTbl;
  int op;

  pData = &p->aMem[pOp->p2];
  pKey = &p->aMem[pOp->p3];
  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  assert( pC->pCursor!=0 || pC->pseudoTable );
  assert( pKey->flags & MEM_Int );
  assert( pC->isTable );
  REGISTER_TRACE(pOp->p2, pData);
................................................................................
      if( !pC->pData ) goto no_mem;
      memcpy(pC->pData, pData->z, pC->nData);
      pC->pData[pC->nData] = 0;
      pC->pData[pC->nData+1] = 0;
    }
    pC->nullRow = 0;
  }else{

    seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
    if( pData->flags & MEM_Zero ){
      nZero = pData->u.nZero;
    }else{
      nZero = 0;
    }
    sqlite3BtreeSetCachedRowid(pC->pCursor, 0);
    rc = sqlite3BtreeInsert(pC->pCursor, 0, iKey,
................................................................................
  
  pC->rowidIsValid = 0;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;

  /* Invoke the update-hook if required. */
  if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
    zDb = db->aDb[pC->iDb].zName;
    zTbl = pOp->p4.z;
    op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
    assert( pC->isTable );
    db->xUpdateCallback(db->pUpdateArg, op, zDb, zTbl, iKey);
    assert( pC->iDb>=0 );
  }
  break;
}

................................................................................
**
** If P4 is not NULL, then it is the name of the table that P1 is
** pointing to.  The update hook will be invoked, if it exists.
** If P4 is not NULL then the P1 cursor must have been positioned
** using OP_NotFound prior to invoking this opcode.
*/
case OP_Delete: {
  int i;
  i64 iKey;
  VdbeCursor *pC;

  i = pOp->p1;
  iKey = 0;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */

  /* If the update-hook will be invoked, set iKey to the rowid of the
  ** row being deleted.
................................................................................
** it is found in the database file.
**
** If the P1 cursor must be pointing to a valid row (not a NULL row)
** of a real table, not a pseudo-table.
*/
case OP_RowKey:
case OP_RowData: {
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  u32 n;
  i64 n64;

  i = pOp->p1;
  pOut = &p->aMem[pOp->p2];

  /* Note that RowKey and RowData are really exactly the same instruction */
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC->isTable || pOp->opcode==OP_RowKey );
  assert( pC->isIndex || pOp->opcode==OP_RowData );
................................................................................
  assert( pC->nullRow==0 );
  assert( pC->pseudoTable==0 );
  assert( pC->pCursor!=0 );
  pCrsr = pC->pCursor;
  rc = sqlite3VdbeCursorMoveto(pC);
  if( rc ) goto abort_due_to_error;
  if( pC->isIndex ){

    assert( !pC->isTable );
    sqlite3BtreeKeySize(pCrsr, &n64);
    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
      goto too_big;
    }
    n = (int)n64;
  }else{
................................................................................
** P1 is currently point to.
**
** P1 can be either an ordinary table or a virtual table.  There used to
** be a separate OP_VRowid opcode for use with virtual tables, but this
** one opcode now works for both table types.
*/
case OP_Rowid: {                 /* out2-prerelease */
  int i;
  VdbeCursor *pC;
  i64 v;
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  if( pC->nullRow ){
    /* Do nothing so that reg[P2] remains NULL */
    break;
  }else if( pC->deferredMoveto ){
    v = pC->movetoTarget;
  }else if( pC->pseudoTable ){
    v = keyToInt(pC->iKey);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  }else if( pC->pVtabCursor ){


    pVtab = pC->pVtabCursor->pVtab;
    pModule = pVtab->pModule;
    assert( pModule->xRowid );
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    rc = pModule->xRowid(pC->pVtabCursor, &v);
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
................................................................................
/* Opcode: NullRow P1 * * * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always
** write a NULL.
*/
case OP_NullRow: {
  int i;
  VdbeCursor *pC;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  pC = p->apCsr[i];
  assert( pC!=0 );
  pC->nullRow = 1;
  pC->rowidIsValid = 0;
  if( pC->pCursor ){
    sqlite3BtreeClearCursor(pC->pCursor);
................................................................................
** The next use of the Rowid or Column or Next instruction for P1 
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Last: {        /* jump */
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;

  i = pOp->p1;
  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;
................................................................................
** The next use of the Rowid or Column or Next instruction for P1 
** will refer to the first entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
*/
case OP_Rewind: {        /* jump */
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;

  i = pOp->p1;
  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;
................................................................................
** P3 is a flag that provides a hint to the b-tree layer that this
** insert is likely to be an append.
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_IdxInsert: {        /* in2 */
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int nKey;
  const char *zKey;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  assert( pIn2->flags & MEM_Blob );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    assert( pC->isTable==0 );
    rc = ExpandBlob(pIn2);
    if( rc==SQLITE_OK ){
      nKey = pIn2->n;
      zKey = pIn2->z;
      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3, 
          ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
      );
      assert( pC->deferredMoveto==0 );
      pC->cacheStatus = CACHE_STALE;
    }
  }
................................................................................
/* Opcode: IdxDelete P1 P2 P3 * *
**
** The content of P3 registers starting at register P2 form
** an unpacked index key. This opcode removes that entry from the 
** index opened by cursor P1.
*/
case OP_IdxDelete: {
  int i;
  VdbeCursor *pC;
  BtCursor *pCrsr;

  i = pOp->p1;
  assert( pOp->p3>0 );
  assert( pOp->p2>0 && pOp->p2+pOp->p3<=p->nMem+1 );
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res;
    UnpackedRecord r;
................................................................................
** Write into register P2 an integer which is the last entry in the record at
** the end of the index key pointed to by cursor P1.  This integer should be
** the rowid of the table entry to which this index entry points.
**
** See also: Rowid, MakeRecord.
*/
case OP_IdxRowid: {              /* out2-prerelease */
  int i;
  BtCursor *pCrsr;
  VdbeCursor *pC;
  i64 rowid;


  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){

    rc = sqlite3VdbeCursorMoveto(pC);
    if( rc ) goto abort_due_to_error;
    assert( pC->deferredMoveto==0 );
    assert( pC->isTable==0 );
    if( !pC->nullRow ){
      rc = sqlite3VdbeIdxRowid(pCrsr, &rowid);
      if( rc!=SQLITE_OK ){
................................................................................
** Otherwise fall through to the next instruction.
**
** If P5 is non-zero then the key value is increased by an epsilon prior 
** to the comparison.  This makes the opcode work like IdxLE.
*/
case OP_IdxLT:          /* jump, in3 */
case OP_IdxGE: {        /* jump, in3 */
  int i;
  VdbeCursor *pC;
  int res;
  UnpackedRecord r;

  i = pOp->p1;
  assert( i>=0 && i<p->nCursor );
  assert( p->apCsr[i]!=0 );
  if( (pC = p->apCsr[i])->pCursor!=0 ){


    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;
................................................................................
** If AUTOVACUUM is disabled then a zero is stored in register P2.
**
** See also: Clear
*/
case OP_Destroy: {     /* out2-prerelease */
  int iMoved;
  int iCnt;

  Vdbe *pVdbe;
  int iDb;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  iCnt = 0;
  for(pVdbe=db->pVdbe; pVdbe; pVdbe = pVdbe->pNext){
    if( pVdbe->magic==VDBE_MAGIC_RUN && pVdbe->inVtabMethod<2 && pVdbe->pc>=0 ){
      iCnt++;
    }
  }
#else
  iCnt = db->activeVdbeCnt;
#endif
  if( iCnt>1 ){
    rc = SQLITE_LOCKED;
    p->errorAction = OE_Abort;
  }else{
    iDb = pOp->p3;
    assert( iCnt==1 );
    assert( (p->btreeMask & (1<<iDb))!=0 );
    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
    MemSetTypeFlag(pOut, MEM_Int);
    pOut->u.i = iMoved;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( rc==SQLITE_OK && iMoved!=0 ){
................................................................................
** count is incremented by the number of rows in the table being cleared. 
** If P3 is greater than zero, then the value stored in register P3 is
** also incremented by the number of rows in the table being cleared.
**
** See also: Destroy
*/
case OP_Clear: {
  int nChange;
 
  nChange = 0;
  assert( (p->btreeMask & (1<<pOp->p2))!=0 );
  rc = sqlite3BtreeClearTable(
      db->aDb[pOp->p2].pBt, pOp->p1, (pOp->p3 ? &nChange : 0)
  );
  if( pOp->p3 ){
    p->nChange += nChange;
    if( pOp->p3>0 ){
................................................................................
** P1>1.  Write the root page number of the new table into
** register P2.
**
** See documentation on OP_CreateTable for additional information.
*/
case OP_CreateIndex:            /* out2-prerelease */
case OP_CreateTable: {          /* out2-prerelease */
  int pgno;
  int flags;
  Db *pDb;

  pgno = 0;
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (1<<pOp->p1))!=0 );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  if( pOp->opcode==OP_CreateTable ){
    /* flags = BTREE_INTKEY; */
    flags = BTREE_LEAFDATA|BTREE_INTKEY;
................................................................................
** is false, the SQLITE_MASTER table is only parsed if the rest of the
** schema is already loaded into the symbol table.
**
** This opcode invokes the parser to create a new virtual machine,
** then runs the new virtual machine.  It is thus a re-entrant opcode.
*/
case OP_ParseSchema: {
  int iDb;
  const char *zMaster;
  char *zSql;
  InitData initData;

  iDb = pOp->p1;
  assert( iDb>=0 && iDb<db->nDb );

  /* If pOp->p2 is 0, then this opcode is being executed to read a
  ** single row, for example the row corresponding to a new index
  ** created by this VDBE, from the sqlite_master table. It only
  ** does this if the corresponding in-memory schema is currently
  ** loaded. Otherwise, the new index definition can be loaded along
................................................................................
  ** will not be reloaded becuase the db->init.busy flag is set. This
  ** can result in a "no such table: sqlite_master" or "malformed
  ** database schema" error being returned to the user.
  */
  assert( sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
  sqlite3BtreeEnterAll(db);
  if( pOp->p2 || DbHasProperty(db, iDb, DB_SchemaLoaded) ){
    zMaster = SCHEMA_TABLE(iDb);


    initData.db = db;
    initData.iDb = pOp->p1;
    initData.pzErrMsg = &p->zErrMsg;
    zSql = sqlite3MPrintf(db,
       "SELECT name, rootpage, sql FROM '%q'.%s WHERE %s",
       db->aDb[iDb].zName, zMaster, pOp->p4.z);
    if( zSql==0 ){
................................................................................
/* Opcode: LoadAnalysis P1 * * * *
**
** Read the sqlite_stat1 table for database P1 and load the content
** of that table into the internal index hash table.  This will cause
** the analysis to be used when preparing all subsequent queries.
*/
case OP_LoadAnalysis: {
  assert( pOp->p1>=0 && pOp->p1<db->nDb );

  rc = sqlite3AnalysisLoad(db, pOp->p1);
  break;  
}
#endif /* !defined(SQLITE_OMIT_ANALYZE) && !defined(SQLITE_OMIT_PARSER)  */

/* Opcode: DropTable P1 * * P4 *
**
** Remove the internal (in-memory) data structures that describe
................................................................................
** (b) when P4==-1 there is no need to insert the value, as it will
** never be tested for, and (c) when a value that is part of set X is
** inserted, there is no need to search to see if the same value was
** previously inserted as part of set X (only if it was previously
** inserted as part of some other set).
*/
case OP_RowSetTest: {                     /* jump, in1, in3 */
  int iSet;
  int exists;

  iSet = pOp->p4.i;
  assert( pIn3->flags&MEM_Int );

  /* If there is anything other than a rowset object in memory cell P1,
  ** delete it now and initialize P1 with an empty rowset
  */
  if( (pIn1->flags & MEM_RowSet)==0 ){
    sqlite3VdbeMemSetRowSet(pIn1);
    if( (pIn1->flags & MEM_RowSet)==0 ) goto no_mem;
  }

  assert( pOp->p4type==P4_INT32 );
  assert( iSet==-1 || iSet>=0 );
  if( iSet ){

    exists = sqlite3RowSetTest(pIn1->u.pRowSet, 
                               (u8)(iSet>=0 ? iSet & 0xf : 0xff),
                               pIn3->u.i);
    if( exists ){
      pc = pOp->p2 - 1;
      break;
    }
................................................................................
/* Opcode: ContextPush * * * 
**
** Save the current Vdbe context such that it can be restored by a ContextPop
** opcode. The context stores the last insert row id, the last statement change
** count, and the current statement change count.
*/
case OP_ContextPush: {
  int i;
  Context *pContext;

  i = p->contextStackTop++;
  assert( i>=0 );
  /* FIX ME: This should be allocated as part of the vdbe at compile-time */
  if( i>=p->contextStackDepth ){
    p->contextStackDepth = i+1;
    p->contextStack = sqlite3DbReallocOrFree(db, p->contextStack,
                                          sizeof(Context)*(i+1));
    if( p->contextStack==0 ) goto no_mem;
................................................................................
/* Opcode: ContextPop * * * 
**
** Restore the Vdbe context to the state it was in when contextPush was last
** executed. The context stores the last insert row id, the last statement
** change count, and the current statement change count.
*/
case OP_ContextPop: {
  Context *pContext;
  pContext = &p->contextStack[--p->contextStackTop];
  assert( p->contextStackTop>=0 );
  db->lastRowid = pContext->lastRowid;
  p->nChange = pContext->nChange;
  break;
}
#endif /* #ifndef SQLITE_OMIT_TRIGGER */

................................................................................
** structure that specifies the function.  Use register
** P3 as the accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.
*/
case OP_AggStep: {
  int n;
  int i;
  Mem *pMem, *pRec;
  sqlite3_context ctx;
  sqlite3_value **apVal;

  n = pOp->p5;
  assert( n>=0 );
  pRec = &p->aMem[pOp->p2];
  apVal = p->apArg;
  assert( apVal || n==0 );
  for(i=0; i<n; i++, pRec++){
    apVal[i] = pRec;
    storeTypeInfo(pRec, encoding);
................................................................................
**
** 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;
  u8 isWriteLock;

  p1 = pOp->p1; 
  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&0xFF)==SQLITE_LOCKED ){
    const char *z = pOp->p4.z;
    sqlite3SetString(&p->zErrMsg, db, "database table is locked: %s", z);
................................................................................
** xBegin method for that table.
**
** Also, whether or not P4 is set, check that this is not being called from
** within a callback to a virtual table xSync() method. If it is, the error
** code will be set to SQLITE_LOCKED.
*/
case OP_VBegin: {
  sqlite3_vtab *pVtab;
  pVtab = pOp->p4.pVtab;
  rc = sqlite3VtabBegin(db, pVtab);
  if( pVtab ){
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
    pVtab->zErrMsg = 0;
  }
  break;
................................................................................
/* Opcode: VOpen P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** P1 is a cursor number.  This opcode opens a cursor to the virtual
** table and stores that cursor in P1.
*/
case OP_VOpen: {
  VdbeCursor *pCur;
  sqlite3_vtab_cursor *pVtabCursor;
  sqlite3_vtab *pVtab;
  sqlite3_module *pModule;

  pCur = 0;
  pVtabCursor = 0;
  pVtab = pOp->p4.pVtab;
  pModule = (sqlite3_module *)pVtab->pModule;

  assert(pVtab && pModule);
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xOpen(pVtab, &pVtabCursor);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
................................................................................
**
** A jump is made to P2 if the result set after filtering would be empty.
*/
case OP_VFilter: {   /* jump */
  int nArg;
  int iQuery;
  const sqlite3_module *pModule;
  Mem *pQuery;
  Mem *pArgc;
  sqlite3_vtab_cursor *pVtabCursor;
  sqlite3_vtab *pVtab;
  VdbeCursor *pCur;
  int res;
  int i;
  Mem **apArg;

  pQuery = &p->aMem[pOp->p3];
  pArgc = &pQuery[1];
  pCur = p->apCsr[pOp->p1];

  REGISTER_TRACE(pOp->p3, pQuery);
  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 */
  {
    res = 0;

    apArg = p->apArg;
    for(i = 0; i<nArg; i++){
      apArg[i] = &pArgc[i+1];
      storeTypeInfo(apArg[i], 0);
    }

    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    sqlite3VtabLock(pVtab);
................................................................................
** jump to instruction P2.  Or, if the virtual table has reached
** the end of its result set, then fall through to the next instruction.
*/
case OP_VNext: {   /* jump */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  int res = 0;
  VdbeCursor *pCur;

  pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xNext );
................................................................................
/* Opcode: VRename P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xRename method. The value
** in register P1 is passed as the zName argument to the xRename method.
*/
case OP_VRename: {
  sqlite3_vtab *pVtab;
  Mem *pName;

  pVtab = pOp->p4.pVtab;
  pName = &p->aMem[pOp->p1];
  assert( pVtab->pModule->xRename );
  REGISTER_TRACE(pOp->p1, pName);

  Stringify(pName, encoding);

  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  sqlite3VtabLock(pVtab);
................................................................................
** a row to delete.
**
** P1 is a boolean flag. If it is set to true and the xUpdate call
** is successful, then the value returned by sqlite3_last_insert_rowid() 
** is set to the value of the rowid for the row just inserted.
*/
case OP_VUpdate: {
  sqlite3_vtab *pVtab;
  sqlite3_module *pModule;
  int nArg;
  int i;
  sqlite_int64 rowid;
  Mem **apArg;
  Mem *pX;

  pVtab = pOp->p4.pVtab;
  pModule = (sqlite3_module *)pVtab->pModule;
  nArg = pOp->p2;
  assert( pOp->p4type==P4_VTAB );
  if( pModule->xUpdate==0 ){
    sqlite3SetString(&p->zErrMsg, db, "read-only table");
    rc = SQLITE_ERROR;
  }else{


    apArg = p->apArg;
    pX = &p->aMem[pOp->p3];
    for(i=0; i<nArg; i++){
      storeTypeInfo(pX, 0);
      apArg[i] = pX;
      pX++;
    }
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    sqlite3VtabLock(pVtab);
................................................................................

#ifndef  SQLITE_OMIT_PAGER_PRAGMAS
/* Opcode: Pagecount P1 P2 * * *
**
** Write the current number of pages in database P1 to memory cell P2.
*/
case OP_Pagecount: {            /* out2-prerelease */
  int p1;
  int nPage;
  Pager *pPager;

  p1 = pOp->p1; 
  pPager = sqlite3BtreePager(db->aDb[p1].pBt);
  rc = sqlite3PagerPagecount(pPager, &nPage);
  if( rc==SQLITE_OK ){
    pOut->flags = MEM_Int;
    pOut->u.i = nPage;
  }
  break;
}
................................................................................
#ifndef SQLITE_OMIT_TRACE
/* Opcode: Trace * * * P4 *
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
*/
case OP_Trace: {
  char *zTrace;

  zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
  if( zTrace ){
    if( db->xTrace ){
      db->xTrace(db->pTraceArg, zTrace);
    }
#ifdef SQLITE_DEBUG
    if( (db->flags & SQLITE_SqlTrace)!=0 ){
      sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);

Added tool/vdbe-compress.tcl.

























































































































































































































































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#!/usr/bin/tcl
#
# This script makes modifications to the vdbe.c source file which reduce
# the amount of stack space required by the sqlite3VdbeExec() routine.
#
# The modifications performed by this script are optional.  The vdbe.c
# source file will compile correctly with and without the modifications
# performed by this script.  And all routines within vdbe.c will compute
# the same result.  The modifications made by this script merely help
# the C compiler to generate code for sqlite3VdbeExec() that uses less
# stack space.
#
# Script usage:
#
#          mv vdbe.c vdbe.c.template
#          tclsh vdbe-compress.tcl <vdbe.c.template >vdbe.c
#
# Modifications made:
#
# All modifications are within the sqlite3VdbeExec() function.  The
# modifications seek to reduce the amount of stack space allocated by
# this routine by moving local variable declarations out of individual
# opcode implementations and into a single large union.  The union contains
# a separate structure for each opcode and that structure contains the
# local variables used by that opcode.  In this way, the total amount
# of stack space required by sqlite3VdbeExec() is reduced from the
# sum of all local variables to the maximum of the local variable space
# required for any single opcode.
#
# In order to be recognized by this script, local variables must appear
# on the first line after the open curly-brace that begins a new opcode
# implementation.  Local variables must not have initializers, though they
# may be commented.
#
# The union definition is inserted in place of a special marker comment
# in the preamble to the sqlite3VdbeExec() implementation.
#
#############################################################################
#
set beforeUnion {}   ;# C code before union
set unionDef {}      ;# C code of the union
set afterUnion {}    ;# C code after the union
set sCtr 0           ;# Context counter

# Read program text up to the spot where the union should be
# inserted.
#
while {![eof stdin]} {
  set line [gets stdin]
  if {[regexp {INSERT STACK UNION HERE} $line]} break
  append beforeUnion $line\n
}

# Process the remaining text.  Build up the union definition as we go.
#
set vlist {}
set seenDecl 0
set namechars {abcdefghijklmnopqrstuvwxyz}
set nnc [string length $namechars]
while {![eof stdin]} {
  set line [gets stdin]
  if {[regexp "^case (OP_\\w+): \173" $line all operator]} {
    append afterUnion $line\n
    set vlist {}
    while {![eof stdin]} {
      set line [gets stdin]
      if {[regexp {^ +(const )?\w+ \*?(\w+)(\[.*\])?;} $line \
           all constKeyword vname notused1]} {
        if {!$seenDecl} {
          set sname {}
          append sname [string index $namechars [expr {$sCtr/$nnc}]]
          append sname [string index $namechars [expr {$sCtr%$nnc}]]
          incr sCtr
          append unionDef "    struct ${operator}_stack_vars \173\n"
          append afterUnion \
             "#if 0  /* local variables moved into u.$sname */\n"
          set seenDecl 1
        }
        append unionDef "    $line\n"
        append afterUnion $line\n
        lappend vlist $vname
      } else {
        break
      }
    }
    if {$seenDecl} {
      append unionDef   "    \175 $sname;\n"
      append afterUnion "#endif /* local variables moved into u.$sname */\n"
    }
    set seenDecl 0
  }
  if {[regexp "^\175" $line]} {
    append afterUnion $line\n
    set vlist {}
  } elseif {[llength $vlist]>0} {
    append line " "
    foreach v $vlist {
      regsub -all "(\[^a-zA-Z0-9>.\])${v}(\\W)" $line "\\1u.$sname.$v\\2" line
    }
    append afterUnion [string trimright $line]\n
  } elseif {$line=="" && [eof stdin]} {
    # no-op
  } else {
    append afterUnion $line\n
  }
}

# Output the resulting text.
#
puts -nonewline $beforeUnion
puts "  /********************************************************************"
puts "  ** Automatically generated code"
puts "  **"
puts "  ** The following union is automatically generated by the"
puts "  ** vdbe-compress.tcl script.  The purpose of this union is to"
puts "  ** reduce the amount of stack space required by this function."
puts "  ** See comments in the vdbe-compress.tcl script for details."
puts "  */"
puts "  union vdbeExecUnion \173"
puts -nonewline $unionDef
puts "  \175 u;"
puts "  /* End automatically generated code"
puts "  ********************************************************************/"
puts -nonewline $afterUnion