Initial commit

Signed-off-by: Mavridis Philippe <[email protected]>

1 files changed, 1997 insertions, 0 deletions

diff --git a/src/sqlite/vdbeaux.c b/src/sqlite/vdbeaux.c
new file mode 100644
index 0000000..e64831e
--- /dev/null
+++ b/src/sqlite/vdbeaux.c
@@ -0,0 +1,1997 @@
+/*
+** 2003 September 6
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains code used for creating, destroying, and populating
+** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
+** to version 2.8.7, all this code was combined into the vdbe.c source file.
+** But that file was getting too big so this subroutines were split out.
+*/
+#include "sqliteInt.h"
+#include "os.h"
+#include <ctype.h>
+#include "vdbeInt.h"
+
+
+/*
+** When debugging the code generator in a symbolic debugger, one can
+** set the sqlite3_vdbe_addop_trace to 1 and all opcodes will be printed
+** as they are added to the instruction stream.
+*/
+#ifndef NDEBUG
+int sqlite3_vdbe_addop_trace = 0;
+#endif
+
+
+/*
+** Create a new virtual database engine.
+*/
+Vdbe *sqlite3VdbeCreate(sqlite3 *db){
+  Vdbe *p;
+  p = sqliteMalloc( sizeof(Vdbe) );
+  if( p==0 ) return 0;
+  p->db = db;
+  if( db->pVdbe ){
+    db->pVdbe->pPrev = p;
+  }
+  p->pNext = db->pVdbe;
+  p->pPrev = 0;
+  db->pVdbe = p;
+  p->magic = VDBE_MAGIC_INIT;
+  return p;
+}
+
+/*
+** Turn tracing on or off
+*/
+void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
+  p->trace = trace;
+}
+
+/*
+** Resize the Vdbe.aOp array so that it contains at least N
+** elements. If the Vdbe is in VDBE_MAGIC_RUN state, then
+** the Vdbe.aOp array will be sized to contain exactly N 
+** elements.
+*/
+static void resizeOpArray(Vdbe *p, int N){
+  if( p->magic==VDBE_MAGIC_RUN ){
+    assert( N==p->nOp );
+    p->nOpAlloc = N;
+    p->aOp = sqliteRealloc(p->aOp, N*sizeof(Op));
+  }else if( p->nOpAlloc<N ){
+    int oldSize = p->nOpAlloc;
+    p->nOpAlloc = N+100;
+    p->aOp = sqliteRealloc(p->aOp, p->nOpAlloc*sizeof(Op));
+    if( p->aOp ){
+      memset(&p->aOp[oldSize], 0, (p->nOpAlloc-oldSize)*sizeof(Op));
+    }
+  }
+}
+
+/*
+** Add a new instruction to the list of instructions current in the
+** VDBE.  Return the address of the new instruction.
+**
+** Parameters:
+**
+**    p               Pointer to the VDBE
+**
+**    op              The opcode for this instruction
+**
+**    p1, p2          First two of the three possible operands.
+**
+** Use the sqlite3VdbeResolveLabel() function to fix an address and
+** the sqlite3VdbeChangeP3() function to change the value of the P3
+** operand.
+*/
+int sqlite3VdbeAddOp(Vdbe *p, int op, int p1, int p2){
+  int i;
+  VdbeOp *pOp;
+
+  i = p->nOp;
+  p->nOp++;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  resizeOpArray(p, i+1);
+  if( p->aOp==0 ){
+    return 0;
+  }
+  pOp = &p->aOp[i];
+  pOp->opcode = op;
+  pOp->p1 = p1;
+  pOp->p2 = p2;
+  pOp->p3 = 0;
+  pOp->p3type = P3_NOTUSED;
+#ifdef SQLITE_DEBUG
+  if( sqlite3_vdbe_addop_trace ) sqlite3VdbePrintOp(0, i, &p->aOp[i]);
+#endif
+  return i;
+}
+
+/*
+** Add an opcode that includes the p3 value.
+*/
+int sqlite3VdbeOp3(Vdbe *p, int op, int p1, int p2, const char *zP3,int p3type){
+  int addr = sqlite3VdbeAddOp(p, op, p1, p2);
+  sqlite3VdbeChangeP3(p, addr, zP3, p3type);
+  return addr;
+}
+
+/*
+** Create a new symbolic label for an instruction that has yet to be
+** coded.  The symbolic label is really just a negative number.  The
+** label can be used as the P2 value of an operation.  Later, when
+** the label is resolved to a specific address, the VDBE will scan
+** through its operation list and change all values of P2 which match
+** the label into the resolved address.
+**
+** The VDBE knows that a P2 value is a label because labels are
+** always negative and P2 values are suppose to be non-negative.
+** Hence, a negative P2 value is a label that has yet to be resolved.
+**
+** Zero is returned if a malloc() fails.
+*/
+int sqlite3VdbeMakeLabel(Vdbe *p){
+  int i;
+  i = p->nLabel++;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( i>=p->nLabelAlloc ){
+    p->nLabelAlloc = p->nLabelAlloc*2 + 10;
+    p->aLabel = sqliteRealloc( p->aLabel, p->nLabelAlloc*sizeof(p->aLabel[0]));
+  }
+  if( p->aLabel ){
+    p->aLabel[i] = -1;
+  }
+  return -1-i;
+}
+
+/*
+** Resolve label "x" to be the address of the next instruction to
+** be inserted.  The parameter "x" must have been obtained from
+** a prior call to sqlite3VdbeMakeLabel().
+*/
+void sqlite3VdbeResolveLabel(Vdbe *p, int x){
+  int j = -1-x;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  assert( j>=0 && j<p->nLabel );
+  if( p->aLabel ){
+    p->aLabel[j] = p->nOp;
+  }
+}
+
+/*
+** Return non-zero if opcode 'op' is guarenteed not to push more values
+** onto the VDBE stack than it pops off.
+*/
+static int opcodeNoPush(u8 op){
+  /* The 10 NOPUSH_MASK_n constants are defined in the automatically
+  ** generated header file opcodes.h. Each is a 16-bit bitmask, one
+  ** bit corresponding to each opcode implemented by the virtual
+  ** machine in vdbe.c. The bit is true if the word "no-push" appears
+  ** in a comment on the same line as the "case OP_XXX:" in 
+  ** sqlite3VdbeExec() in vdbe.c.
+  **
+  ** If the bit is true, then the corresponding opcode is guarenteed not
+  ** to grow the stack when it is executed. Otherwise, it may grow the
+  ** stack by at most one entry.
+  **
+  ** NOPUSH_MASK_0 corresponds to opcodes 0 to 15. NOPUSH_MASK_1 contains
+  ** one bit for opcodes 16 to 31, and so on.
+  **
+  ** 16-bit bitmasks (rather than 32-bit) are specified in opcodes.h 
+  ** because the file is generated by an awk program. Awk manipulates
+  ** all numbers as floating-point and we don't want to risk a rounding
+  ** error if someone builds with an awk that uses (for example) 32-bit 
+  ** IEEE floats.
+  */ 
+  static const u32 masks[5] = {
+    NOPUSH_MASK_0 + (NOPUSH_MASK_1<<16),
+    NOPUSH_MASK_2 + (NOPUSH_MASK_3<<16),
+    NOPUSH_MASK_4 + (NOPUSH_MASK_5<<16),
+    NOPUSH_MASK_6 + (NOPUSH_MASK_7<<16),
+    NOPUSH_MASK_8 + (NOPUSH_MASK_9<<16)
+  };
+  return (masks[op>>5] & (1<<(op&0x1F)));
+}
+
+#ifndef NDEBUG
+int sqlite3VdbeOpcodeNoPush(u8 op){
+  return opcodeNoPush(op);
+}
+#endif
+
+/*
+** Loop through the program looking for P2 values that are negative.
+** Each such value is a label.  Resolve the label by setting the P2
+** value to its correct non-zero value.
+**
+** This routine is called once after all opcodes have been inserted.
+**
+** Variable *pMaxFuncArgs is set to the maximum value of any P1 argument 
+** to an OP_Function or P2 to an OP_AggFunc opcode. This is used by 
+** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
+**
+** The integer *pMaxStack is set to the maximum number of vdbe stack
+** entries that static analysis reveals this program might need.
+**
+** This routine also does the following optimization:  It scans for
+** Halt instructions where P1==SQLITE_CONSTRAINT or P2==OE_Abort or for
+** IdxInsert instructions where P2!=0.  If no such instruction is
+** found, then every Statement instruction is changed to a Noop.  In
+** this way, we avoid creating the statement journal file unnecessarily.
+*/
+static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs, int *pMaxStack){
+  int i;
+  int nMaxArgs = 0;
+  int nMaxStack = p->nOp;
+  Op *pOp;
+  int *aLabel = p->aLabel;
+  int doesStatementRollback = 0;
+  int hasStatementBegin = 0;
+  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+    u8 opcode = pOp->opcode;
+
+    /* Todo: Maybe OP_AggFunc should change to use P1 in the same
+     * way as OP_Function. 
+     */
+    if( opcode==OP_Function ){
+      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
+    }else if( opcode==OP_AggFunc ){
+      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
+    }else if( opcode==OP_Halt ){
+      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
+        doesStatementRollback = 1;
+      }
+    }else if( opcode==OP_IdxInsert ){
+      if( pOp->p2 ){
+        doesStatementRollback = 1;
+      }
+    }else if( opcode==OP_Statement ){
+      hasStatementBegin = 1;
+    }
+
+    if( opcodeNoPush(opcode) ){
+      nMaxStack--;
+    }
+
+    if( pOp->p2>=0 ) continue;
+    assert( -1-pOp->p2<p->nLabel );
+    pOp->p2 = aLabel[-1-pOp->p2];
+  }
+  sqliteFree(p->aLabel);
+  p->aLabel = 0;
+
+  *pMaxFuncArgs = nMaxArgs;
+  *pMaxStack = nMaxStack;
+
+  /* If we never rollback a statement transaction, then statement
+  ** transactions are not needed.  So change every OP_Statement
+  ** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()
+  ** which can be expensive on some platforms.
+  */
+  if( hasStatementBegin && !doesStatementRollback ){
+    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
+      if( pOp->opcode==OP_Statement ){
+        pOp->opcode = OP_Noop;
+      }
+    }
+  }
+}
+
+/*
+** Return the address of the next instruction to be inserted.
+*/
+int sqlite3VdbeCurrentAddr(Vdbe *p){
+  assert( p->magic==VDBE_MAGIC_INIT );
+  return p->nOp;
+}
+
+/*
+** Add a whole list of operations to the operation stack.  Return the
+** address of the first operation added.
+*/
+int sqlite3VdbeAddOpList(Vdbe *p, int nOp, VdbeOpList const *aOp){
+  int addr;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  resizeOpArray(p, p->nOp + nOp);
+  if( p->aOp==0 ){
+    return 0;
+  }
+  addr = p->nOp;
+  if( nOp>0 ){
+    int i;
+    VdbeOpList const *pIn = aOp;
+    for(i=0; i<nOp; i++, pIn++){
+      int p2 = pIn->p2;
+      VdbeOp *pOut = &p->aOp[i+addr];
+      pOut->opcode = pIn->opcode;
+      pOut->p1 = pIn->p1;
+      pOut->p2 = p2<0 ? addr + ADDR(p2) : p2;
+      pOut->p3 = pIn->p3;
+      pOut->p3type = pIn->p3 ? P3_STATIC : P3_NOTUSED;
+#ifdef SQLITE_DEBUG
+      if( sqlite3_vdbe_addop_trace ){
+        sqlite3VdbePrintOp(0, i+addr, &p->aOp[i+addr]);
+      }
+#endif
+    }
+    p->nOp += nOp;
+  }
+  return addr;
+}
+
+/*
+** Change the value of the P1 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+*/
+void sqlite3VdbeChangeP1(Vdbe *p, int addr, int val){
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+    p->aOp[addr].p1 = val;
+  }
+}
+
+/*
+** Change the value of the P2 operand for a specific instruction.
+** This routine is useful for setting a jump destination.
+*/
+void sqlite3VdbeChangeP2(Vdbe *p, int addr, int val){
+  assert( val>=0 );
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p && addr>=0 && p->nOp>addr && p->aOp ){
+    p->aOp[addr].p2 = val;
+  }
+}
+
+/*
+** Change the value of the P3 operand for a specific instruction.
+** This routine is useful when a large program is loaded from a
+** static array using sqlite3VdbeAddOpList but we want to make a
+** few minor changes to the program.
+**
+** If n>=0 then the P3 operand is dynamic, meaning that a copy of
+** the string is made into memory obtained from sqliteMalloc().
+** A value of n==0 means copy bytes of zP3 up to and including the
+** first null byte.  If n>0 then copy n+1 bytes of zP3.
+**
+** If n==P3_KEYINFO it means that zP3 is a pointer to a KeyInfo structure.
+** A copy is made of the KeyInfo structure into memory obtained from
+** sqliteMalloc, to be freed when the Vdbe is finalized.
+** n==P3_KEYINFO_HANDOFF indicates that zP3 points to a KeyInfo structure
+** stored in memory that the caller has obtained from sqliteMalloc. The 
+** caller should not free the allocation, it will be freed when the Vdbe is
+** finalized.
+** 
+** Other values of n (P3_STATIC, P3_COLLSEQ etc.) indicate that zP3 points
+** to a string or structure that is guaranteed to exist for the lifetime of
+** the Vdbe. In these cases we can just copy the pointer.
+**
+** If addr<0 then change P3 on the most recently inserted instruction.
+*/
+void sqlite3VdbeChangeP3(Vdbe *p, int addr, const char *zP3, int n){
+  Op *pOp;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p==0 || p->aOp==0 ){
+    if( n==P3_DYNAMIC || n==P3_KEYINFO_HANDOFF ){
+      sqliteFree((void*)zP3);
+    }
+    if( n==P3_MEM ){
+      sqlite3ValueFree((sqlite3_value *)zP3);
+    }
+    return;
+  }
+  if( addr<0 || addr>=p->nOp ){
+    addr = p->nOp - 1;
+    if( addr<0 ) return;
+  }
+  pOp = &p->aOp[addr];
+  if( pOp->p3 && pOp->p3type==P3_DYNAMIC ){
+    sqliteFree(pOp->p3);
+    pOp->p3 = 0;
+  }
+  if( zP3==0 ){
+    pOp->p3 = 0;
+    pOp->p3type = P3_NOTUSED;
+  }else if( n==P3_KEYINFO ){
+    KeyInfo *pKeyInfo;
+    int nField, nByte;
+    nField = ((KeyInfo*)zP3)->nField;
+    nByte = sizeof(*pKeyInfo) + (nField-1)*sizeof(pKeyInfo->aColl[0]);
+    pKeyInfo = sqliteMallocRaw( nByte );
+    pOp->p3 = (char*)pKeyInfo;
+    if( pKeyInfo ){
+      memcpy(pKeyInfo, zP3, nByte);
+      pOp->p3type = P3_KEYINFO;
+    }else{
+      pOp->p3type = P3_NOTUSED;
+    }
+  }else if( n==P3_KEYINFO_HANDOFF ){
+    pOp->p3 = (char*)zP3;
+    pOp->p3type = P3_KEYINFO;
+  }else if( n<0 ){
+    pOp->p3 = (char*)zP3;
+    pOp->p3type = n;
+  }else{
+    if( n==0 ) n = strlen(zP3);
+    pOp->p3 = sqliteStrNDup(zP3, n);
+    pOp->p3type = P3_DYNAMIC;
+  }
+}
+
+#ifndef NDEBUG
+/*
+** Replace the P3 field of the most recently coded instruction with
+** comment text.
+*/
+void sqlite3VdbeComment(Vdbe *p, const char *zFormat, ...){
+  va_list ap;
+  assert( p->nOp>0 );
+  assert( p->aOp==0 || p->aOp[p->nOp-1].p3==0 );
+  va_start(ap, zFormat);
+  sqlite3VdbeChangeP3(p, -1, sqlite3VMPrintf(zFormat, ap), P3_DYNAMIC);
+  va_end(ap);
+}
+#endif
+
+/*
+** If the P3 operand to the specified instruction appears
+** to be a quoted string token, then this procedure removes 
+** the quotes.
+**
+** The quoting operator can be either a grave ascent (ASCII 0x27)
+** or a double quote character (ASCII 0x22).  Two quotes in a row
+** resolve to be a single actual quote character within the string.
+*/
+void sqlite3VdbeDequoteP3(Vdbe *p, int addr){
+  Op *pOp;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  if( p->aOp==0 ) return;
+  if( addr<0 || addr>=p->nOp ){
+    addr = p->nOp - 1;
+    if( addr<0 ) return;
+  }
+  pOp = &p->aOp[addr];
+  if( pOp->p3==0 || pOp->p3[0]==0 ) return;
+  if( pOp->p3type==P3_STATIC ){
+    pOp->p3 = sqliteStrDup(pOp->p3);
+    pOp->p3type = P3_DYNAMIC;
+  }
+  assert( pOp->p3type==P3_DYNAMIC );
+  sqlite3Dequote(pOp->p3);
+}
+
+/*
+** Search the current program starting at instruction addr for the given
+** opcode and P2 value.  Return the address plus 1 if found and 0 if not
+** found.
+*/
+int sqlite3VdbeFindOp(Vdbe *p, int addr, int op, int p2){
+  int i;
+  assert( p->magic==VDBE_MAGIC_INIT );
+  for(i=addr; i<p->nOp; i++){
+    if( p->aOp[i].opcode==op && p->aOp[i].p2==p2 ) return i+1;
+  }
+  return 0;
+}
+
+/*
+** Return the opcode for a given address.
+*/
+VdbeOp *sqlite3VdbeGetOp(Vdbe *p, int addr){
+  assert( p->magic==VDBE_MAGIC_INIT );
+  assert( addr>=0 && addr<p->nOp );
+  return &p->aOp[addr];
+}
+
+#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
+     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Compute a string that describes the P3 parameter for an opcode.
+** Use zTemp for any required temporary buffer space.
+*/
+static char *displayP3(Op *pOp, char *zTemp, int nTemp){
+  char *zP3;
+  assert( nTemp>=20 );
+  switch( pOp->p3type ){
+    case P3_KEYINFO: {
+      int i, j;
+      KeyInfo *pKeyInfo = (KeyInfo*)pOp->p3;
+      sprintf(zTemp, "keyinfo(%d", pKeyInfo->nField);
+      i = strlen(zTemp);
+      for(j=0; j<pKeyInfo->nField; j++){
+        CollSeq *pColl = pKeyInfo->aColl[j];
+        if( pColl ){
+          int n = strlen(pColl->zName);
+          if( i+n>nTemp-6 ){
+            strcpy(&zTemp[i],",...");
+            break;
+          }
+          zTemp[i++] = ',';
+          if( pKeyInfo->aSortOrder && pKeyInfo->aSortOrder[j] ){
+            zTemp[i++] = '-';
+          }
+          strcpy(&zTemp[i], pColl->zName);
+          i += n;
+        }else if( i+4<nTemp-6 ){
+          strcpy(&zTemp[i],",nil");
+          i += 4;
+        }
+      }
+      zTemp[i++] = ')';
+      zTemp[i] = 0;
+      assert( i<nTemp );
+      zP3 = zTemp;
+      break;
+    }
+    case P3_COLLSEQ: {
+      CollSeq *pColl = (CollSeq*)pOp->p3;
+      sprintf(zTemp, "collseq(%.20s)", pColl->zName);
+      zP3 = zTemp;
+      break;
+    }
+    case P3_FUNCDEF: {
+      FuncDef *pDef = (FuncDef*)pOp->p3;
+      char zNum[30];
+      sprintf(zTemp, "%.*s", nTemp, pDef->zName);
+      sprintf(zNum,"(%d)", pDef->nArg);
+      if( strlen(zTemp)+strlen(zNum)+1<=nTemp ){
+        strcat(zTemp, zNum);
+      }
+      zP3 = zTemp;
+      break;
+    }
+    default: {
+      zP3 = pOp->p3;
+      if( zP3==0 || pOp->opcode==OP_Noop ){
+        zP3 = "";
+      }
+    }
+  }
+  return zP3;
+}
+#endif
+
+
+#if defined(VDBE_PROFILE) || defined(SQLITE_DEBUG)
+/*
+** Print a single opcode.  This routine is used for debugging only.
+*/
+void sqlite3VdbePrintOp(FILE *pOut, int pc, Op *pOp){
+  char *zP3;
+  char zPtr[50];
+  static const char *zFormat1 = "%4d %-13s %4d %4d %s\n";
+  if( pOut==0 ) pOut = stdout;
+  zP3 = displayP3(pOp, zPtr, sizeof(zPtr));
+  fprintf(pOut, zFormat1,
+      pc, sqlite3OpcodeNames[pOp->opcode], pOp->p1, pOp->p2, zP3);
+  fflush(pOut);
+}
+#endif
+
+/*
+** Release an array of N Mem elements
+*/
+static void releaseMemArray(Mem *p, int N){
+  if( p ){
+    while( N-->0 ){
+      sqlite3VdbeMemRelease(p++);
+    }
+  }
+}
+
+#ifndef SQLITE_OMIT_EXPLAIN
+/*
+** Give a listing of the program in the virtual machine.
+**
+** The interface is the same as sqlite3VdbeExec().  But instead of
+** running the code, it invokes the callback once for each instruction.
+** This feature is used to implement "EXPLAIN".
+*/
+int sqlite3VdbeList(
+  Vdbe *p                   /* The VDBE */
+){
+  sqlite3 *db = p->db;
+  int i;
+  int rc = SQLITE_OK;
+
+  assert( p->explain );
+  if( p->magic!=VDBE_MAGIC_RUN ) return SQLITE_MISUSE;
+  assert( db->magic==SQLITE_MAGIC_BUSY );
+  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
+
+  /* Even though this opcode does not put dynamic strings onto the
+  ** the stack, they may become dynamic if the user calls
+  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
+  */
+  if( p->pTos==&p->aStack[4] ){
+    releaseMemArray(p->aStack, 5);
+  }
+  p->resOnStack = 0;
+
+
+  i = p->pc++;
+  if( i>=p->nOp ){
+    p->rc = SQLITE_OK;
+    rc = SQLITE_DONE;
+  }else if( db->flags & SQLITE_Interrupt ){
+    db->flags &= ~SQLITE_Interrupt;
+    p->rc = SQLITE_INTERRUPT;
+    rc = SQLITE_ERROR;
+    sqlite3SetString(&p->zErrMsg, sqlite3ErrStr(p->rc), (char*)0);
+  }else{
+    Op *pOp = &p->aOp[i];
+    Mem *pMem = p->aStack;
+    pMem->flags = MEM_Int;
+    pMem->type = SQLITE_INTEGER;
+    pMem->i = i;                                /* Program counter */
+    pMem++;
+
+    pMem->flags = MEM_Static|MEM_Str|MEM_Term;
+    pMem->z = sqlite3OpcodeNames[pOp->opcode];  /* Opcode */
+    pMem->n = strlen(pMem->z);
+    pMem->type = SQLITE_TEXT;
+    pMem->enc = SQLITE_UTF8;
+    pMem++;
+
+    pMem->flags = MEM_Int;
+    pMem->i = pOp->p1;                          /* P1 */
+    pMem->type = SQLITE_INTEGER;
+    pMem++;
+
+    pMem->flags = MEM_Int;
+    pMem->i = pOp->p2;                          /* P2 */
+    pMem->type = SQLITE_INTEGER;
+    pMem++;
+
+    pMem->flags = MEM_Short|MEM_Str|MEM_Term;   /* P3 */
+    pMem->z = displayP3(pOp, pMem->zShort, sizeof(pMem->zShort));
+    pMem->type = SQLITE_TEXT;
+    pMem->enc = SQLITE_UTF8;
+
+    p->nResColumn = 5;
+    p->pTos = pMem;
+    p->rc = SQLITE_OK;
+    p->resOnStack = 1;
+    rc = SQLITE_ROW;
+  }
+  return rc;
+}
+#endif /* SQLITE_OMIT_EXPLAIN */
+
+/*
+** Print the SQL that was used to generate a VDBE program.
+*/
+void sqlite3VdbePrintSql(Vdbe *p){
+#ifdef SQLITE_DEBUG
+  int nOp = p->nOp;
+  VdbeOp *pOp;
+  if( nOp<1 ) return;
+  pOp = &p->aOp[nOp-1];
+  if( pOp->opcode==OP_Noop && pOp->p3!=0 ){
+    const char *z = pOp->p3;
+    while( isspace(*(u8*)z) ) z++;
+    printf("SQL: [%s]\n", z);
+  }
+#endif
+}
+
+/*
+** Prepare a virtual machine for execution.  This involves things such
+** as allocating stack space and initializing the program counter.
+** After the VDBE has be prepped, it can be executed by one or more
+** calls to sqlite3VdbeExec().  
+**
+** This is the only way to move a VDBE from VDBE_MAGIC_INIT to
+** VDBE_MAGIC_RUN.
+*/
+void sqlite3VdbeMakeReady(
+  Vdbe *p,                       /* The VDBE */
+  int nVar,                      /* Number of '?' see in the SQL statement */
+  int nMem,                      /* Number of memory cells to allocate */
+  int nCursor,                   /* Number of cursors to allocate */
+  int nAgg,                      /* Number of aggregate contexts required */
+  int isExplain                  /* True if the EXPLAIN keywords is present */
+){
+  int n;
+
+  assert( p!=0 );
+  assert( p->magic==VDBE_MAGIC_INIT );
+
+  /* There should be at least one opcode.
+  */
+  assert( p->nOp>0 );
+
+  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. This
+   * is because the call to resizeOpArray() below may shrink the
+   * p->aOp[] array to save memory if called when in VDBE_MAGIC_RUN 
+   * state.
+   */
+  p->magic = VDBE_MAGIC_RUN;
+
+  /* No instruction ever pushes more than a single element onto the
+  ** stack.  And the stack never grows on successive executions of the
+  ** same loop.  So the total number of instructions is an upper bound
+  ** on the maximum stack depth required.  (Added later:)  The
+  ** resolveP2Values() call computes a tighter upper bound on the
+  ** stack size.
+  **
+  ** Allocation all the stack space we will ever need.
+  */
+  if( p->aStack==0 ){
+    int nArg;       /* Maximum number of args passed to a user function. */
+    int nStack;     /* Maximum number of stack entries required */
+    resolveP2Values(p, &nArg, &nStack);
+    resizeOpArray(p, p->nOp);
+    assert( nVar>=0 );
+    assert( nStack<p->nOp );
+    nStack = isExplain ? 10 : nStack;
+    p->aStack = sqliteMalloc(
+        nStack*sizeof(p->aStack[0])    /* aStack */
+      + nArg*sizeof(Mem*)              /* apArg */
+      + nVar*sizeof(Mem)               /* aVar */
+      + nVar*sizeof(char*)             /* azVar */
+      + nMem*sizeof(Mem)               /* aMem */
+      + nCursor*sizeof(Cursor*)        /* apCsr */
+      + nAgg*sizeof(Agg)               /* Aggregate contexts */
+    );
+    if( !sqlite3_malloc_failed ){
+      p->aMem = &p->aStack[nStack];
+      p->nMem = nMem;
+      p->aVar = &p->aMem[nMem];
+      p->nVar = nVar;
+      p->okVar = 0;
+      p->apArg = (Mem**)&p->aVar[nVar];
+      p->azVar = (char**)&p->apArg[nArg];
+      p->apCsr = (Cursor**)&p->azVar[nVar];
+      if( nAgg>0 ){
+        p->nAgg = nAgg;
+        p->apAgg = (Agg*)&p->apCsr[nCursor];
+      }
+      p->nCursor = nCursor;
+      for(n=0; n<nVar; n++){
+        p->aVar[n].flags = MEM_Null;
+      }
+    }
+  }
+  p->pAgg = p->apAgg;
+  for(n=0; n<p->nMem; n++){
+    p->aMem[n].flags = MEM_Null;
+  }
+
+#ifdef SQLITE_DEBUG
+  if( (p->db->flags & SQLITE_VdbeListing)!=0
+    || sqlite3OsFileExists("vdbe_explain")
+  ){
+    int i;
+    printf("VDBE Program Listing:\n");
+    sqlite3VdbePrintSql(p);
+    for(i=0; i<p->nOp; i++){
+      sqlite3VdbePrintOp(stdout, i, &p->aOp[i]);
+    }
+  }
+  if( sqlite3OsFileExists("vdbe_trace") ){
+    p->trace = stdout;
+  }
+#endif
+  p->pTos = &p->aStack[-1];
+  p->pc = -1;
+  p->rc = SQLITE_OK;
+  p->uniqueCnt = 0;
+  p->returnDepth = 0;
+  p->errorAction = OE_Abort;
+  p->popStack =  0;
+  p->explain |= isExplain;
+  p->magic = VDBE_MAGIC_RUN;
+  p->nChange = 0;
+#ifdef VDBE_PROFILE
+  {
+    int i;
+    for(i=0; i<p->nOp; i++){
+      p->aOp[i].cnt = 0;
+      p->aOp[i].cycles = 0;
+    }
+  }
+#endif
+}
+
+
+/*
+** Remove any elements that remain on the sorter for the VDBE given.
+*/
+void sqlite3VdbeSorterReset(Vdbe *p){
+  while( p->pSort ){
+    Sorter *pSorter = p->pSort;
+    p->pSort = pSorter->pNext;
+    sqliteFree(pSorter->zKey);
+    sqlite3VdbeMemRelease(&pSorter->data);
+    sqliteFree(pSorter);
+  }
+  p->pSortTail = 0;
+}
+
+/*
+** Free all resources allociated with AggElem pElem, an element of
+** aggregate pAgg.
+*/
+static void freeAggElem(AggElem *pElem, Agg *pAgg){
+  int i;
+  for(i=0; i<pAgg->nMem; i++){
+    Mem *pMem = &pElem->aMem[i];
+    if( pAgg->apFunc && pAgg->apFunc[i] && (pMem->flags & MEM_AggCtx)!=0 ){
+      sqlite3_context ctx;
+      ctx.pFunc = pAgg->apFunc[i];
+      ctx.s.flags = MEM_Null;
+      ctx.pAgg = pMem->z;
+      ctx.cnt = pMem->i;
+      ctx.isError = 0;
+      (*ctx.pFunc->xFinalize)(&ctx);
+      pMem->z = ctx.pAgg;
+      if( pMem->z!=0 && pMem->z!=pMem->zShort ){
+        sqliteFree(pMem->z);
+      }
+      sqlite3VdbeMemRelease(&ctx.s);
+    }else{
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  sqliteFree(pElem);
+}
+
+/*
+** Reset an Agg structure.  Delete all its contents.
+**
+** For installable aggregate functions, if the step function has been
+** called, make sure the finalizer function has also been called.  The
+** finalizer might need to free memory that was allocated as part of its
+** private context.  If the finalizer has not been called yet, call it
+** now.
+**
+** If db is NULL, then this is being called from sqliteVdbeReset(). In
+** this case clean up all references to the temp-table used for
+** aggregates (if it was ever opened).
+**
+** If db is not NULL, then this is being called from with an OP_AggReset
+** opcode. Open the temp-table, if it has not already been opened and
+** delete the contents of the table used for aggregate information, ready
+** for the next round of aggregate processing.
+*/
+int sqlite3VdbeAggReset(sqlite3 *db, Agg *pAgg, KeyInfo *pKeyInfo){
+  int rc = 0;
+  BtCursor *pCsr;
+
+  if( !pAgg ) return SQLITE_OK;
+  pCsr = pAgg->pCsr;
+  assert( (pCsr && pAgg->nTab>0) || (!pCsr && pAgg->nTab==0)
+         || sqlite3_malloc_failed );
+
+  /* If pCsr is not NULL, then the table used for aggregate information
+  ** is open. Loop through it and free the AggElem* structure pointed at
+  ** by each entry. If the finalizer has not been called for an AggElem,
+  ** do that too. Finally, clear the btree table itself.
+  */
+  if( pCsr ){
+    int res;
+    assert( pAgg->pBtree );
+    assert( pAgg->nTab>0 );
+
+    rc=sqlite3BtreeFirst(pCsr, &res);
+    while( res==0 && rc==SQLITE_OK ){
+      AggElem *pElem;
+      rc = sqlite3BtreeData(pCsr, 0, sizeof(AggElem*), (char *)&pElem);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
+      assert( pAgg->apFunc!=0 );
+      freeAggElem(pElem, pAgg);
+      rc=sqlite3BtreeNext(pCsr, &res);
+    }
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    sqlite3BtreeCloseCursor(pCsr);
+    sqlite3BtreeClearTable(pAgg->pBtree, pAgg->nTab);
+  }else{ 
+    /* The cursor may not be open because the aggregator was never used,
+    ** or it could be that it was used but there was no GROUP BY clause.
+    */
+    if( pAgg->pCurrent ){
+      freeAggElem(pAgg->pCurrent, pAgg);
+    }
+  }
+
+  /* If db is not NULL and we have not yet and we have not yet opened
+  ** the temporary btree then do so and create the table to store aggregate
+  ** information.
+  **
+  ** If db is NULL, then close the temporary btree if it is open.
+  */
+  if( db ){
+    if( !pAgg->pBtree ){
+      assert( pAgg->nTab==0 );
+#ifndef SQLITE_OMIT_MEMORYDB
+      rc = sqlite3BtreeFactory(db, ":memory:", 0, TEMP_PAGES, &pAgg->pBtree);
+#else
+      rc = sqlite3BtreeFactory(db, 0, 0, TEMP_PAGES, &pAgg->pBtree);
+#endif
+      if( rc!=SQLITE_OK ) return rc;
+      sqlite3BtreeBeginTrans(pAgg->pBtree, 1);
+      rc = sqlite3BtreeCreateTable(pAgg->pBtree, &pAgg->nTab, 0);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    assert( pAgg->nTab!=0 );
+
+    rc = sqlite3BtreeCursor(pAgg->pBtree, pAgg->nTab, 1,
+        sqlite3VdbeRecordCompare, pKeyInfo, &pAgg->pCsr);
+    if( rc!=SQLITE_OK ) return rc;
+  }else{
+    if( pAgg->pBtree ){
+      sqlite3BtreeClose(pAgg->pBtree);
+      pAgg->pBtree = 0;
+      pAgg->nTab = 0;
+    }
+    pAgg->pCsr = 0;
+  }
+
+  if( pAgg->apFunc ){ 
+    sqliteFree(pAgg->apFunc);
+    pAgg->apFunc = 0;
+  }
+  pAgg->pCurrent = 0;
+  pAgg->nMem = 0;
+  pAgg->searching = 0;
+  return SQLITE_OK;
+}
+
+
+/*
+** Delete a keylist
+*/
+void sqlite3VdbeKeylistFree(Keylist *p){
+  while( p ){
+    Keylist *pNext = p->pNext;
+    sqliteFree(p);
+    p = pNext;
+  }
+}
+
+/*
+** Close a cursor and release all the resources that cursor happens
+** to hold.
+*/
+void sqlite3VdbeFreeCursor(Cursor *pCx){
+  if( pCx==0 ){
+    return;
+  }
+  if( pCx->pCursor ){
+    sqlite3BtreeCloseCursor(pCx->pCursor);
+  }
+  if( pCx->pBt ){
+    sqlite3BtreeClose(pCx->pBt);
+  }
+  sqliteFree(pCx->pData);
+  sqliteFree(pCx->aType);
+  sqliteFree(pCx);
+}
+
+/*
+** Close all cursors
+*/
+static void closeAllCursors(Vdbe *p){
+  int i;
+  if( p->apCsr==0 ) return;
+  for(i=0; i<p->nCursor; i++){
+    sqlite3VdbeFreeCursor(p->apCsr[i]);
+    p->apCsr[i] = 0;
+  }
+}
+
+/*
+** Clean up the VM after execution.
+**
+** This routine will automatically close any cursors, lists, and/or
+** sorters that were left open.  It also deletes the values of
+** variables in the aVar[] array.
+*/
+static void Cleanup(Vdbe *p){
+  int i;
+  if( p->aStack ){
+    releaseMemArray(p->aStack, 1 + (p->pTos - p->aStack));
+    p->pTos = &p->aStack[-1];
+  }
+  closeAllCursors(p);
+  releaseMemArray(p->aMem, p->nMem);
+  if( p->pList ){
+    sqlite3VdbeKeylistFree(p->pList);
+    p->pList = 0;
+  }
+  if( p->contextStack ){
+    for(i=0; i<p->contextStackTop; i++){
+      sqlite3VdbeKeylistFree(p->contextStack[i].pList);
+    }
+    sqliteFree(p->contextStack);
+  }
+  sqlite3VdbeSorterReset(p);
+  for(i=0; i<p->nAgg; i++){
+    sqlite3VdbeAggReset(0, &p->apAgg[i], 0);
+  }
+  p->contextStack = 0;
+  p->contextStackDepth = 0;
+  p->contextStackTop = 0;
+  sqliteFree(p->zErrMsg);
+  p->zErrMsg = 0;
+}
+
+/*
+** Set the number of result columns that will be returned by this SQL
+** statement. This is now set at compile time, rather than during
+** execution of the vdbe program so that sqlite3_column_count() can
+** be called on an SQL statement before sqlite3_step().
+*/
+void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
+  Mem *pColName;
+  int n;
+  assert( 0==p->nResColumn );
+  p->nResColumn = nResColumn;
+  n = nResColumn*2;
+  p->aColName = pColName = (Mem*)sqliteMalloc( sizeof(Mem)*n );
+  if( p->aColName==0 ) return;
+  while( n-- > 0 ){
+    (pColName++)->flags = MEM_Null;
+  }
+}
+
+/*
+** Set the name of the idx'th column to be returned by the SQL statement.
+** zName must be a pointer to a nul terminated string.
+**
+** This call must be made after a call to sqlite3VdbeSetNumCols().
+**
+** If N==P3_STATIC  it means that zName is a pointer to a constant static
+** string and we can just copy the pointer. If it is P3_DYNAMIC, then 
+** the string is freed using sqliteFree() when the vdbe is finished with
+** it. Otherwise, N bytes of zName are copied.
+*/
+int sqlite3VdbeSetColName(Vdbe *p, int idx, const char *zName, int N){
+  int rc;
+  Mem *pColName;
+  assert( idx<(2*p->nResColumn) );
+  if( sqlite3_malloc_failed ) return SQLITE_NOMEM;
+  assert( p->aColName!=0 );
+  pColName = &(p->aColName[idx]);
+  if( N==P3_DYNAMIC || N==P3_STATIC ){
+    rc = sqlite3VdbeMemSetStr(pColName, zName, -1, SQLITE_UTF8, SQLITE_STATIC);
+  }else{
+    rc = sqlite3VdbeMemSetStr(pColName, zName, N, SQLITE_UTF8,SQLITE_TRANSIENT);
+  }
+  if( rc==SQLITE_OK && N==P3_DYNAMIC ){
+    pColName->flags = (pColName->flags&(~MEM_Static))|MEM_Dyn;
+    pColName->xDel = 0;
+  }
+  return rc;
+}
+
+/*
+** A read or write transaction may or may not be active on database handle
+** db. If a transaction is active, commit it. If there is a
+** write-transaction spanning more than one database file, this routine
+** takes care of the master journal trickery.
+*/
+static int vdbeCommit(sqlite3 *db){
+  int i;
+  int nTrans = 0;  /* Number of databases with an active write-transaction */
+  int rc = SQLITE_OK;
+  int needXcommit = 0;
+
+  for(i=0; i<db->nDb; i++){ 
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt && sqlite3BtreeIsInTrans(pBt) ){
+      needXcommit = 1;
+      if( i!=1 ) nTrans++;
+    }
+  }
+
+  /* If there are any write-transactions at all, invoke the commit hook */
+  if( needXcommit && db->xCommitCallback ){
+    int rc;
+    sqlite3SafetyOff(db);
+    rc = db->xCommitCallback(db->pCommitArg);
+    sqlite3SafetyOn(db);
+    if( rc ){
+      return SQLITE_CONSTRAINT;
+    }
+  }
+
+  /* The simple case - no more than one database file (not counting the
+  ** TEMP database) has a transaction active.   There is no need for the
+  ** master-journal.
+  **
+  ** If the return value of sqlite3BtreeGetFilename() is a zero length
+  ** string, it means the main database is :memory:.  In that case we do
+  ** not support atomic multi-file commits, so use the simple case then
+  ** too.
+  */
+  if( 0==strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt)) || nTrans<=1 ){
+    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        rc = sqlite3BtreeSync(pBt, 0);
+      }
+    }
+
+    /* Do the commit only if all databases successfully synced */
+    if( rc==SQLITE_OK ){
+      for(i=0; i<db->nDb; i++){
+        Btree *pBt = db->aDb[i].pBt;
+        if( pBt ){
+          sqlite3BtreeCommit(pBt);
+        }
+      }
+    }
+  }
+
+  /* The complex case - There is a multi-file write-transaction active.
+  ** This requires a master journal file to ensure the transaction is
+  ** committed atomicly.
+  */
+#ifndef SQLITE_OMIT_DISKIO
+  else{
+    char *zMaster = 0;   /* File-name for the master journal */
+    char const *zMainFile = sqlite3BtreeGetFilename(db->aDb[0].pBt);
+    OsFile master;
+
+    /* Select a master journal file name */
+    do {
+      u32 random;
+      sqliteFree(zMaster);
+      sqlite3Randomness(sizeof(random), &random);
+      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
+      if( !zMaster ){
+        return SQLITE_NOMEM;
+      }
+    }while( sqlite3OsFileExists(zMaster) );
+
+    /* Open the master journal. */
+    memset(&master, 0, sizeof(master));
+    rc = sqlite3OsOpenExclusive(zMaster, &master, 0);
+    if( rc!=SQLITE_OK ){
+      sqliteFree(zMaster);
+      return rc;
+    }
+ 
+    /* Write the name of each database file in the transaction into the new
+    ** master journal file. If an error occurs at this point close
+    ** and delete the master journal file. All the individual journal files
+    ** still have 'null' as the master journal pointer, so they will roll
+    ** back independently if a failure occurs.
+    */
+    for(i=0; i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( i==1 ) continue;   /* Ignore the TEMP database */
+      if( pBt && sqlite3BtreeIsInTrans(pBt) ){
+        char const *zFile = sqlite3BtreeGetJournalname(pBt);
+        if( zFile[0]==0 ) continue;  /* Ignore :memory: databases */
+        rc = sqlite3OsWrite(&master, zFile, strlen(zFile)+1);
+        if( rc!=SQLITE_OK ){
+          sqlite3OsClose(&master);
+          sqlite3OsDelete(zMaster);
+          sqliteFree(zMaster);
+          return rc;
+        }
+      }
+    }
+
+
+    /* Sync the master journal file. Before doing this, open the directory
+    ** the master journal file is store in so that it gets synced too.
+    */
+    zMainFile = sqlite3BtreeGetDirname(db->aDb[0].pBt);
+    rc = sqlite3OsOpenDirectory(zMainFile, &master);
+    if( rc!=SQLITE_OK || (rc = sqlite3OsSync(&master))!=SQLITE_OK ){
+      sqlite3OsClose(&master);
+      sqlite3OsDelete(zMaster);
+      sqliteFree(zMaster);
+      return rc;
+    }
+
+    /* Sync all the db files involved in the transaction. The same call
+    ** sets the master journal pointer in each individual journal. If
+    ** an error occurs here, do not delete the master journal file.
+    **
+    ** If the error occurs during the first call to sqlite3BtreeSync(),
+    ** then there is a chance that the master journal file will be
+    ** orphaned. But we cannot delete it, in case the master journal
+    ** file name was written into the journal file before the failure
+    ** occured.
+    */
+    for(i=0; i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt && sqlite3BtreeIsInTrans(pBt) ){
+        rc = sqlite3BtreeSync(pBt, zMaster);
+        if( rc!=SQLITE_OK ){
+          sqlite3OsClose(&master);
+          sqliteFree(zMaster);
+          return rc;
+        }
+      }
+    }
+    sqlite3OsClose(&master);
+
+    /* Delete the master journal file. This commits the transaction. After
+    ** doing this the directory is synced again before any individual
+    ** transaction files are deleted.
+    */
+    rc = sqlite3OsDelete(zMaster);
+    assert( rc==SQLITE_OK );
+    sqliteFree(zMaster);
+    zMaster = 0;
+    rc = sqlite3OsSyncDirectory(zMainFile);
+    if( rc!=SQLITE_OK ){
+      /* This is not good. The master journal file has been deleted, but
+      ** the directory sync failed. There is no completely safe course of
+      ** action from here. The individual journals contain the name of the
+      ** master journal file, but there is no way of knowing if that
+      ** master journal exists now or if it will exist after the operating
+      ** system crash that may follow the fsync() failure.
+      */
+      return rc;
+    }
+
+    /* All files and directories have already been synced, so the following
+    ** calls to sqlite3BtreeCommit() are only closing files and deleting
+    ** journals. If something goes wrong while this is happening we don't
+    ** really care. The integrity of the transaction is already guaranteed,
+    ** but some stray 'cold' journals may be lying around. Returning an
+    ** error code won't help matters.
+    */
+    for(i=0; i<db->nDb; i++){ 
+      Btree *pBt = db->aDb[i].pBt;
+      if( pBt ){
+        sqlite3BtreeCommit(pBt);
+      }
+    }
+  }
+#endif
+
+  return rc;
+}
+
+/*
+** Find every active VM other than pVdbe and change its status to
+** aborted.  This happens when one VM causes a rollback due to an
+** ON CONFLICT ROLLBACK clause (for example).  The other VMs must be
+** aborted so that they do not have data rolled out from underneath
+** them leading to a segfault.
+*/
+static void abortOtherActiveVdbes(Vdbe *pVdbe){
+  Vdbe *pOther;
+  for(pOther=pVdbe->db->pVdbe; pOther; pOther=pOther->pNext){
+    if( pOther==pVdbe ) continue;
+    if( pOther->magic!=VDBE_MAGIC_RUN || pOther->pc<0 ) continue;
+    closeAllCursors(pOther);
+    pOther->aborted = 1;
+  }
+}
+
+/* 
+** This routine checks that the sqlite3.activeVdbeCnt count variable
+** matches the number of vdbe's in the list sqlite3.pVdbe that are
+** currently active. An assertion fails if the two counts do not match.
+** This is an internal self-check only - it is not an essential processing
+** step.
+**
+** This is a no-op if NDEBUG is defined.
+*/
+#ifndef NDEBUG
+static void checkActiveVdbeCnt(sqlite3 *db){
+  Vdbe *p;
+  int cnt = 0;
+  p = db->pVdbe;
+  while( p ){
+    if( p->magic==VDBE_MAGIC_RUN && p->pc>=0 ){
+      cnt++;
+    }
+    p = p->pNext;
+  }
+  assert( cnt==db->activeVdbeCnt );
+}
+#else
+#define checkActiveVdbeCnt(x)
+#endif
+
+/*
+** This routine is called the when a VDBE tries to halt.  If the VDBE
+** has made changes and is in autocommit mode, then commit those
+** changes.  If a rollback is needed, then do the rollback.
+**
+** This routine is the only way to move the state of a VM from
+** SQLITE_MAGIC_RUN to SQLITE_MAGIC_HALT.
+**
+** Return an error code.  If the commit could not complete because of
+** lock contention, return SQLITE_BUSY.  If SQLITE_BUSY is returned, it
+** means the close did not happen and needs to be repeated.
+*/
+int sqlite3VdbeHalt(Vdbe *p){
+  sqlite3 *db = p->db;
+  int i;
+  int (*xFunc)(Btree *pBt) = 0;  /* Function to call on each btree backend */
+
+  if( p->magic!=VDBE_MAGIC_RUN ){
+    /* Already halted.  Nothing to do. */
+    assert( p->magic==VDBE_MAGIC_HALT );
+    return SQLITE_OK;
+  }
+  closeAllCursors(p);
+  checkActiveVdbeCnt(db);
+  if( p->pc<0 ){
+    /* No commit or rollback needed if the program never started */
+  }else if( db->autoCommit && db->activeVdbeCnt==1 ){
+    if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+      /* The auto-commit flag is true, there are no other active queries
+      ** using this handle and the vdbe program was successful or hit an
+      ** 'OR FAIL' constraint. This means a commit is required.
+      */
+      int rc = vdbeCommit(db);
+      if( rc==SQLITE_BUSY ){
+        return SQLITE_BUSY;
+      }else if( rc!=SQLITE_OK ){
+        p->rc = rc;
+        xFunc = sqlite3BtreeRollback;
+      }
+    }else{
+      xFunc = sqlite3BtreeRollback;
+    }
+  }else{
+    if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
+      xFunc = sqlite3BtreeCommitStmt;
+    }else if( p->errorAction==OE_Abort ){
+      xFunc = sqlite3BtreeRollbackStmt;
+    }else{
+      xFunc = sqlite3BtreeRollback;
+      db->autoCommit = 1;
+      abortOtherActiveVdbes(p);
+    }
+  }
+
+  /* If xFunc is not NULL, then it is one of sqlite3BtreeRollback,
+  ** sqlite3BtreeRollbackStmt or sqlite3BtreeCommitStmt. Call it once on
+  ** each backend. If an error occurs and the return code is still
+  ** SQLITE_OK, set the return code to the new error value.
+  */
+  for(i=0; xFunc && i<db->nDb; i++){ 
+    int rc;
+    Btree *pBt = db->aDb[i].pBt;
+    if( pBt ){
+      rc = xFunc(pBt);
+      if( p->rc==SQLITE_OK ) p->rc = rc;
+    }
+  }
+
+  /* If this was an INSERT, UPDATE or DELETE, set the change counter. */
+  if( p->changeCntOn && p->pc>=0 ){
+    if( !xFunc || xFunc==sqlite3BtreeCommitStmt ){
+      sqlite3VdbeSetChanges(db, p->nChange);
+    }else{
+      sqlite3VdbeSetChanges(db, 0);
+    }
+    p->nChange = 0;
+  }
+
+  /* Rollback or commit any schema changes that occurred. */
+  if( p->rc!=SQLITE_OK ){
+    sqlite3RollbackInternalChanges(db);
+  }else if( db->flags & SQLITE_InternChanges ){
+    sqlite3CommitInternalChanges(db);
+  }
+
+  /* We have successfully halted and closed the VM.  Record this fact. */
+  if( p->pc>=0 ){
+    db->activeVdbeCnt--;
+  }
+  p->magic = VDBE_MAGIC_HALT;
+  checkActiveVdbeCnt(db);
+
+  return SQLITE_OK;
+}
+
+/*
+** Clean up a VDBE after execution but do not delete the VDBE just yet.
+** Write any error messages into *pzErrMsg.  Return the result code.
+**
+** After this routine is run, the VDBE should be ready to be executed
+** again.
+**
+** To look at it another way, this routine resets the state of the
+** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
+** VDBE_MAGIC_INIT.
+*/
+int sqlite3VdbeReset(Vdbe *p){
+  if( p->magic!=VDBE_MAGIC_RUN && p->magic!=VDBE_MAGIC_HALT ){
+    sqlite3Error(p->db, SQLITE_MISUSE, 0);
+    return SQLITE_MISUSE;
+  }
+
+  /* If the VM did not run to completion or if it encountered an
+  ** error, then it might not have been halted properly.  So halt
+  ** it now.
+  */
+  sqlite3VdbeHalt(p);
+
+  /* If the VDBE has be run even partially, then transfer the error code
+  ** and error message from the VDBE into the main database structure.  But
+  ** if the VDBE has just been set to run but has not actually executed any
+  ** instructions yet, leave the main database error information unchanged.
+  */
+  if( p->pc>=0 ){
+    if( p->zErrMsg ){
+      sqlite3Error(p->db, p->rc, "%s", p->zErrMsg);
+      sqliteFree(p->zErrMsg);
+      p->zErrMsg = 0;
+    }else if( p->rc ){
+      sqlite3Error(p->db, p->rc, 0);
+    }else{
+      sqlite3Error(p->db, SQLITE_OK, 0);
+    }
+  }else if( p->rc && p->expired ){
+    /* The expired flag was set on the VDBE before the first call
+    ** to sqlite3_step(). For consistency (since sqlite3_step() was
+    ** called), set the database error in this case as well.
+    */
+    sqlite3Error(p->db, p->rc, 0);
+  }
+
+  /* Reclaim all memory used by the VDBE
+  */
+  Cleanup(p);
+
+  /* Save profiling information from this VDBE run.
+  */
+  assert( p->pTos<&p->aStack[p->pc<0?0:p->pc] || sqlite3_malloc_failed==1 );
+#ifdef VDBE_PROFILE
+  {
+    FILE *out = fopen("vdbe_profile.out", "a");
+    if( out ){
+      int i;
+      fprintf(out, "---- ");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%02x", p->aOp[i].opcode);
+      }
+      fprintf(out, "\n");
+      for(i=0; i<p->nOp; i++){
+        fprintf(out, "%6d %10lld %8lld ",
+           p->aOp[i].cnt,
+           p->aOp[i].cycles,
+           p->aOp[i].cnt>0 ? p->aOp[i].cycles/p->aOp[i].cnt : 0
+        );
+        sqlite3VdbePrintOp(out, i, &p->aOp[i]);
+      }
+      fclose(out);
+    }
+  }
+#endif
+  p->magic = VDBE_MAGIC_INIT;
+  p->aborted = 0;
+  if( p->rc==SQLITE_SCHEMA ){
+    sqlite3ResetInternalSchema(p->db, 0);
+  }
+  return p->rc;
+}
+ 
+/*
+** Clean up and delete a VDBE after execution.  Return an integer which is
+** the result code.  Write any error message text into *pzErrMsg.
+*/
+int sqlite3VdbeFinalize(Vdbe *p){
+  int rc = SQLITE_OK;
+
+  if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
+    rc = sqlite3VdbeReset(p);
+  }else if( p->magic!=VDBE_MAGIC_INIT ){
+    return SQLITE_MISUSE;
+  }
+  sqlite3VdbeDelete(p);
+  return rc;
+}
+
+/*
+** Call the destructor for each auxdata entry in pVdbeFunc for which
+** the corresponding bit in mask is clear.  Auxdata entries beyond 31
+** are always destroyed.  To destroy all auxdata entries, call this
+** routine with mask==0.
+*/
+void sqlite3VdbeDeleteAuxData(VdbeFunc *pVdbeFunc, int mask){
+  int i;
+  for(i=0; i<pVdbeFunc->nAux; i++){
+    struct AuxData *pAux = &pVdbeFunc->apAux[i];
+    if( (i>31 || !(mask&(1<<i))) && pAux->pAux ){
+      if( pAux->xDelete ){
+        pAux->xDelete(pAux->pAux);
+      }
+      pAux->pAux = 0;
+    }
+  }
+}
+
+/*
+** Delete an entire VDBE.
+*/
+void sqlite3VdbeDelete(Vdbe *p){
+  int i;
+  if( p==0 ) return;
+  Cleanup(p);
+  if( p->pPrev ){
+    p->pPrev->pNext = p->pNext;
+  }else{
+    assert( p->db->pVdbe==p );
+    p->db->pVdbe = p->pNext;
+  }
+  if( p->pNext ){
+    p->pNext->pPrev = p->pPrev;
+  }
+  if( p->aOp ){
+    for(i=0; i<p->nOp; i++){
+      Op *pOp = &p->aOp[i];
+      if( pOp->p3type==P3_DYNAMIC || pOp->p3type==P3_KEYINFO ){
+        sqliteFree(pOp->p3);
+      }
+      if( pOp->p3type==P3_VDBEFUNC ){
+        VdbeFunc *pVdbeFunc = (VdbeFunc *)pOp->p3;
+        sqlite3VdbeDeleteAuxData(pVdbeFunc, 0);
+        sqliteFree(pVdbeFunc);
+      }
+      if( pOp->p3type==P3_MEM ){
+        sqlite3ValueFree((sqlite3_value*)pOp->p3);
+      }
+    }
+    sqliteFree(p->aOp);
+  }
+  releaseMemArray(p->aVar, p->nVar);
+  sqliteFree(p->aLabel);
+  sqliteFree(p->aStack);
+  releaseMemArray(p->aColName, p->nResColumn*2);
+  sqliteFree(p->aColName);
+  p->magic = VDBE_MAGIC_DEAD;
+  sqliteFree(p);
+}
+
+/*
+** If a MoveTo operation is pending on the given cursor, then do that
+** MoveTo now.  Return an error code.  If no MoveTo is pending, this
+** routine does nothing and returns SQLITE_OK.
+*/
+int sqlite3VdbeCursorMoveto(Cursor *p){
+  if( p->deferredMoveto ){
+    int res, rc;
+    extern int sqlite3_search_count;
+    assert( p->isTable );
+    if( p->isTable ){
+      rc = sqlite3BtreeMoveto(p->pCursor, 0, p->movetoTarget, &res);
+    }else{
+      rc = sqlite3BtreeMoveto(p->pCursor,(char*)&p->movetoTarget,
+                              sizeof(i64),&res);
+    }
+    if( rc ) return rc;
+    *p->pIncrKey = 0;
+    p->lastRowid = keyToInt(p->movetoTarget);
+    p->rowidIsValid = res==0;
+    if( res<0 ){
+      rc = sqlite3BtreeNext(p->pCursor, &res);
+      if( rc ) return rc;
+    }
+    sqlite3_search_count++;
+    p->deferredMoveto = 0;
+    p->cacheValid = 0;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The following functions:
+**
+** sqlite3VdbeSerialType()
+** sqlite3VdbeSerialTypeLen()
+** sqlite3VdbeSerialRead()
+** sqlite3VdbeSerialLen()
+** sqlite3VdbeSerialWrite()
+**
+** encapsulate the code that serializes values for storage in SQLite
+** data and index records. Each serialized value consists of a
+** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
+** integer, stored as a varint.
+**
+** In an SQLite index record, the serial type is stored directly before
+** the blob of data that it corresponds to. In a table record, all serial
+** types are stored at the start of the record, and the blobs of data at
+** the end. Hence these functions allow the caller to handle the
+** serial-type and data blob seperately.
+**
+** The following table describes the various storage classes for data:
+**
+**   serial type        bytes of data      type
+**   --------------     ---------------    ---------------
+**      0                     0            NULL
+**      1                     1            signed integer
+**      2                     2            signed integer
+**      3                     3            signed integer
+**      4                     4            signed integer
+**      5                     6            signed integer
+**      6                     8            signed integer
+**      7                     8            IEEE float
+**     8-11                                reserved for expansion
+**    N>=12 and even       (N-12)/2        BLOB
+**    N>=13 and odd        (N-13)/2        text
+**
+*/
+
+/*
+** Return the serial-type for the value stored in pMem.
+*/
+u32 sqlite3VdbeSerialType(Mem *pMem){
+  int flags = pMem->flags;
+
+  if( flags&MEM_Null ){
+    return 0;
+  }
+  if( flags&MEM_Int ){
+    /* Figure out whether to use 1, 2, 4, 6 or 8 bytes. */
+#   define MAX_6BYTE ((((i64)0x00001000)<<32)-1)
+    i64 i = pMem->i;
+    u64 u = i<0 ? -i : i;
+    if( u<=127 ) return 1;
+    if( u<=32767 ) return 2;
+    if( u<=8388607 ) return 3;
+    if( u<=2147483647 ) return 4;
+    if( u<=MAX_6BYTE ) return 5;
+    return 6;
+  }
+  if( flags&MEM_Real ){
+    return 7;
+  }
+  if( flags&MEM_Str ){
+    int n = pMem->n;
+    assert( n>=0 );
+    return ((n*2) + 13);
+  }
+  if( flags&MEM_Blob ){
+    return (pMem->n*2 + 12);
+  }
+  return 0;
+}
+
+/*
+** Return the length of the data corresponding to the supplied serial-type.
+*/
+int sqlite3VdbeSerialTypeLen(u32 serial_type){
+  if( serial_type>=12 ){
+    return (serial_type-12)/2;
+  }else{
+    static const u8 aSize[] = { 0, 1, 2, 3, 4, 6, 8, 8, 0, 0, 0, 0 };
+    return aSize[serial_type];
+  }
+}
+
+/*
+** Write the serialized data blob for the value stored in pMem into 
+** buf. It is assumed that the caller has allocated sufficient space.
+** Return the number of bytes written.
+*/ 
+int sqlite3VdbeSerialPut(unsigned char *buf, Mem *pMem){
+  u32 serial_type = sqlite3VdbeSerialType(pMem);
+  int len;
+
+  /* NULL */
+  if( serial_type==0 ){
+    return 0;
+  }
+ 
+  /* Integer and Real */
+  if( serial_type<=7 ){
+    u64 v;
+    int i;
+    if( serial_type==7 ){
+      v = *(u64*)&pMem->r;
+    }else{
+      v = *(u64*)&pMem->i;
+    }
+    len = i = sqlite3VdbeSerialTypeLen(serial_type);
+    while( i-- ){
+      buf[i] = (v&0xFF);
+      v >>= 8;
+    }
+    return len;
+  }
+  
+  /* String or blob */
+  assert( serial_type>=12 );
+  len = sqlite3VdbeSerialTypeLen(serial_type);
+  memcpy(buf, pMem->z, len);
+  return len;
+}
+
+/*
+** Deserialize the data blob pointed to by buf as serial type serial_type
+** and store the result in pMem.  Return the number of bytes read.
+*/ 
+int sqlite3VdbeSerialGet(
+  const unsigned char *buf,     /* Buffer to deserialize from */
+  u32 serial_type,              /* Serial type to deserialize */
+  Mem *pMem                     /* Memory cell to write value into */
+){
+  switch( serial_type ){
+    case 8:    /* Reserved for future use */
+    case 9:    /* Reserved for future use */
+    case 10:   /* Reserved for future use */
+    case 11:   /* Reserved for future use */
+    case 0: {  /* NULL */
+      pMem->flags = MEM_Null;
+      break;
+    }
+    case 1: { /* 1-byte signed integer */
+      pMem->i = (signed char)buf[0];
+      pMem->flags = MEM_Int;
+      return 1;
+    }
+    case 2: { /* 2-byte signed integer */
+      pMem->i = (((signed char)buf[0])<<8) | buf[1];
+      pMem->flags = MEM_Int;
+      return 2;
+    }
+    case 3: { /* 3-byte signed integer */
+      pMem->i = (((signed char)buf[0])<<16) | (buf[1]<<8) | buf[2];
+      pMem->flags = MEM_Int;
+      return 3;
+    }
+    case 4: { /* 4-byte signed integer */
+      pMem->i = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+      pMem->flags = MEM_Int;
+      return 4;
+    }
+    case 5: { /* 6-byte signed integer */
+      u64 x = (((signed char)buf[0])<<8) | buf[1];
+      u32 y = (buf[2]<<24) | (buf[3]<<16) | (buf[4]<<8) | buf[5];
+      x = (x<<32) | y;
+      pMem->i = *(i64*)&x;
+      pMem->flags = MEM_Int;
+      return 6;
+    }
+    case 6:   /* 6-byte signed integer */
+    case 7: { /* IEEE floating point */
+      u64 x = (buf[0]<<24) | (buf[1]<<16) | (buf[2]<<8) | buf[3];
+      u32 y = (buf[4]<<24) | (buf[5]<<16) | (buf[6]<<8) | buf[7];
+      x = (x<<32) | y;
+      if( serial_type==6 ){
+        pMem->i = *(i64*)&x;
+        pMem->flags = MEM_Int;
+      }else{
+        pMem->r = *(double*)&x;
+        pMem->flags = MEM_Real;
+      }
+      return 8;
+    }
+    default: {
+      int len = (serial_type-12)/2;
+      pMem->z = (char *)buf;
+      pMem->n = len;
+      pMem->xDel = 0;
+      if( serial_type&0x01 ){
+        pMem->flags = MEM_Str | MEM_Ephem;
+      }else{
+        pMem->flags = MEM_Blob | MEM_Ephem;
+      }
+      return len;
+    }
+  }
+  return 0;
+}
+
+/*
+** This function compares the two table rows or index records specified by 
+** {nKey1, pKey1} and {nKey2, pKey2}, returning a negative, zero
+** or positive integer if {nKey1, pKey1} is less than, equal to or 
+** greater than {nKey2, pKey2}.  Both Key1 and Key2 must be byte strings
+** composed by the OP_MakeRecord opcode of the VDBE.
+*/
+int sqlite3VdbeRecordCompare(
+  void *userData,
+  int nKey1, const void *pKey1, 
+  int nKey2, const void *pKey2
+){
+  KeyInfo *pKeyInfo = (KeyInfo*)userData;
+  u32 d1, d2;          /* Offset into aKey[] of next data element */
+  u32 idx1, idx2;      /* Offset into aKey[] of next header element */
+  u32 szHdr1, szHdr2;  /* Number of bytes in header */
+  int i = 0;
+  int nField;
+  int rc = 0;
+  const unsigned char *aKey1 = (const unsigned char *)pKey1;
+  const unsigned char *aKey2 = (const unsigned char *)pKey2;
+
+  Mem mem1;
+  Mem mem2;
+  mem1.enc = pKeyInfo->enc;
+  mem2.enc = pKeyInfo->enc;
+  
+  idx1 = sqlite3GetVarint32(pKey1, &szHdr1);
+  d1 = szHdr1;
+  idx2 = sqlite3GetVarint32(pKey2, &szHdr2);
+  d2 = szHdr2;
+  nField = pKeyInfo->nField;
+  while( idx1<szHdr1 && idx2<szHdr2 ){
+    u32 serial_type1;
+    u32 serial_type2;
+
+    /* Read the serial types for the next element in each key. */
+    idx1 += sqlite3GetVarint32(&aKey1[idx1], &serial_type1);
+    if( d1>=nKey1 && sqlite3VdbeSerialTypeLen(serial_type1)>0 ) break;
+    idx2 += sqlite3GetVarint32(&aKey2[idx2], &serial_type2);
+    if( d2>=nKey2 && sqlite3VdbeSerialTypeLen(serial_type2)>0 ) break;
+
+    /* Assert that there is enough space left in each key for the blob of
+    ** data to go with the serial type just read. This assert may fail if
+    ** the file is corrupted.  Then read the value from each key into mem1
+    ** and mem2 respectively.
+    */
+    d1 += sqlite3VdbeSerialGet(&aKey1[d1], serial_type1, &mem1);
+    d2 += sqlite3VdbeSerialGet(&aKey2[d2], serial_type2, &mem2);
+
+    rc = sqlite3MemCompare(&mem1, &mem2, i<nField ? pKeyInfo->aColl[i] : 0);
+    if( mem1.flags & MEM_Dyn ) sqlite3VdbeMemRelease(&mem1);
+    if( mem2.flags & MEM_Dyn ) sqlite3VdbeMemRelease(&mem2);
+    if( rc!=0 ){
+      break;
+    }
+    i++;
+  }
+
+  /* One of the keys ran out of fields, but all the fields up to that point
+  ** were equal. If the incrKey flag is true, then the second key is
+  ** treated as larger.
+  */
+  if( rc==0 ){
+    if( pKeyInfo->incrKey ){
+      rc = -1;
+    }else if( d1<nKey1 ){
+      rc = 1;
+    }else if( d2<nKey2 ){
+      rc = -1;
+    }
+  }
+
+  if( pKeyInfo->aSortOrder && i<pKeyInfo->nField && pKeyInfo->aSortOrder[i] ){
+    rc = -rc;
+  }
+
+  return rc;
+}
+
+/*
+** The argument is an index entry composed using the OP_MakeRecord opcode.
+** The last entry in this record should be an integer (specifically
+** an integer rowid).  This routine returns the number of bytes in
+** that integer.
+*/
+int sqlite3VdbeIdxRowidLen(int nKey, const u8 *aKey){
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+
+  sqlite3GetVarint32(aKey, &szHdr);
+  sqlite3GetVarint32(&aKey[szHdr-1], &typeRowid);
+  return sqlite3VdbeSerialTypeLen(typeRowid);
+}
+  
+
+/*
+** pCur points at an index entry created using the OP_MakeRecord opcode.
+** Read the rowid (the last field in the record) and store it in *rowid.
+** Return SQLITE_OK if everything works, or an error code otherwise.
+*/
+int sqlite3VdbeIdxRowid(BtCursor *pCur, i64 *rowid){
+  i64 nCellKey;
+  int rc;
+  u32 szHdr;        /* Size of the header */
+  u32 typeRowid;    /* Serial type of the rowid */
+  u32 lenRowid;     /* Size of the rowid */
+  Mem m, v;
+
+  sqlite3BtreeKeySize(pCur, &nCellKey);
+  if( nCellKey<=0 ){
+    return SQLITE_CORRUPT;
+  }
+  rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
+  if( rc ){
+    return rc;
+  }
+  sqlite3GetVarint32(m.z, &szHdr);
+  sqlite3GetVarint32(&m.z[szHdr-1], &typeRowid);
+  lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
+  sqlite3VdbeSerialGet(&m.z[m.n-lenRowid], typeRowid, &v);
+  *rowid = v.i;
+  sqlite3VdbeMemRelease(&m);
+  return SQLITE_OK;
+}
+
+/*
+** Compare the key of the index entry that cursor pC is point to against
+** the key string in pKey (of length nKey).  Write into *pRes a number
+** that is negative, zero, or positive if pC is less than, equal to,
+** or greater than pKey.  Return SQLITE_OK on success.
+**
+** pKey is either created without a rowid or is truncated so that it
+** omits the rowid at the end.  The rowid at the end of the index entry
+** is ignored as well.
+*/
+int sqlite3VdbeIdxKeyCompare(
+  Cursor *pC,                 /* The cursor to compare against */
+  int nKey, const u8 *pKey,   /* The key to compare */
+  int *res                    /* Write the comparison result here */
+){
+  i64 nCellKey;
+  int rc;
+  BtCursor *pCur = pC->pCursor;
+  int lenRowid;
+  Mem m;
+
+  sqlite3BtreeKeySize(pCur, &nCellKey);
+  if( nCellKey<=0 ){
+    *res = 0;
+    return SQLITE_OK;
+  }
+  rc = sqlite3VdbeMemFromBtree(pC->pCursor, 0, nCellKey, 1, &m);
+  if( rc ){
+    return rc;
+  }
+  lenRowid = sqlite3VdbeIdxRowidLen(m.n, m.z);
+  *res = sqlite3VdbeRecordCompare(pC->pKeyInfo, m.n-lenRowid, m.z, nKey, pKey);
+  sqlite3VdbeMemRelease(&m);
+  return SQLITE_OK;
+}
+
+/*
+** This routine sets the value to be returned by subsequent calls to
+** sqlite3_changes() on the database handle 'db'. 
+*/
+void sqlite3VdbeSetChanges(sqlite3 *db, int nChange){
+  db->nChange = nChange;
+  db->nTotalChange += nChange;
+}
+
+/*
+** Set a flag in the vdbe to update the change counter when it is finalised
+** or reset.
+*/
+void sqlite3VdbeCountChanges(Vdbe *v){
+  v->changeCntOn = 1;
+}
+
+/*
+** Mark every prepared statement associated with a database connection
+** as expired.
+**
+** An expired statement means that recompilation of the statement is
+** recommend.  Statements expire when things happen that make their
+** programs obsolete.  Removing user-defined functions or collating
+** sequences, or changing an authorization function are the types of
+** things that make prepared statements obsolete.
+*/
+void sqlite3ExpirePreparedStatements(sqlite3 *db){
+  Vdbe *p;
+  for(p = db->pVdbe; p; p=p->pNext){
+    p->expired = 1;
+  }
+}
+
+/*
+** Return the database associated with the Vdbe.
+*/
+sqlite3 *sqlite3VdbeDb(Vdbe *v){
+  return v->db;
+}