SQLite

    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqlite3VdbeTrace(v, trace);
#endif
    assert( pParse->iCacheLevel==0 );  /* Disables and re-enables match */
    /* A minimum of one cursor is required if autoincrement is used
    *  See ticket [a696379c1f08866] */
    if( pParse->pAinc!=0 && pParse->nTab==0 ) pParse->nTab = 1;
    sqlite3VdbeMakeReady(v, pParse->nVar, pParse->nMem,
                         pParse->nTab, pParse->nMaxArg, pParse->explain,
                         pParse->isMultiWrite && pParse->mayAbort);
    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else{
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;

  z = pExpr->u.zToken;
  assert( z!=0 );
  assert( z[0]!=0 );
  if( z[1]==0 ){
    /* Wildcard of the form "?".  Assign the next variable number */
    assert( z[0]=='?' );
    pExpr->iColumn = (ynVar)(++pParse->nVar);
  }else if( z[0]=='?' ){
    /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
    ** use it as the variable number */
    i64 i;
    int bOk = 0==sqlite3Atoi64(&z[1], &i, sqlite3Strlen30(&z[1]), SQLITE_UTF8);
    pExpr->iColumn = (ynVar)i;
    testcase( i==0 );
    testcase( i==1 );
    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
    testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
    if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
      sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
          db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
    }
    if( i>pParse->nVar ){
      pParse->nVar = (int)i;
    }
  }else{





















    /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
    ** number as the prior appearance of the same name, or if the name
    ** has never appeared before, reuse the same variable number
    */
    int i;
    u32 n;
    n = sqlite3Strlen30(z);
    for(i=0; i<pParse->nVarExpr; i++){
      Expr *pE = pParse->apVarExpr[i];
      assert( pE!=0 );
      if( memcmp(pE->u.zToken, z, n)==0 && pE->u.zToken[n]==0 ){
        pExpr->iColumn = pE->iColumn;
        break;
      }
    }
    if( i>=pParse->nVarExpr ){
      pExpr->iColumn = (ynVar)(++pParse->nVar);

      if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
        pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
        pParse->apVarExpr =

            sqlite3DbReallocOrFree(
              db,

              pParse->apVarExpr,

              pParse->nVarExprAlloc*sizeof(pParse->apVarExpr[0])
            );
      }
      if( !db->mallocFailed ){
        assert( pParse->apVarExpr!=0 );
        pParse->apVarExpr[pParse->nVarExpr++] = pExpr;
      }
    }
  } 
  if( !pParse->nErr && pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
    sqlite3ErrorMsg(pParse, "too many SQL variables");
  }
}

** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
** respectively.
** In other words, the initial ":" or "$" or "@" or "?"
** is included as part of the name.)^
** ^Parameters of the form "?" without a following integer have no name
** and are referred to as "nameless" or "anonymous parameters".
** ^Any parameter that is optimized out of the prepared statement by the 
** query planner becomes a nameless or anonymous parameter.
**
** ^The first host parameter has an index of 1, not 0.
**
** ^If the value N is out of range or if the N-th parameter is
** nameless, then NULL is returned.  ^The returned string is
** always in UTF-8 encoding even if the named parameter was
** originally specified as UTF-16 in [sqlite3_prepare16()] or

  u8 disableTriggers;  /* True to disable triggers */
  double nQueryLoop;   /* Estimated number of iterations of a query */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nVarExpr;        /* Number of used slots in apVarExpr[] */
  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
  Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */
  Vdbe *pReprepare;    /* VM being reprepared (sqlite3Reprepare()) */
  int nAlias;          /* Number of aliased result set columns */
  int nAliasAlloc;     /* Number of allocated slots for aAlias[] */
  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */

  if( pEngine==0 ){
    db->mallocFailed = 1;
    return SQLITE_NOMEM;
  }
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->nVarExpr==0 );
  assert( pParse->nVarExprAlloc==0 );
  assert( pParse->apVarExpr==0 );
  enableLookaside = db->lookaside.bEnabled;
  if( db->lookaside.pStart ) db->lookaside.bEnabled = 1;
  while( !db->mallocFailed && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = &zSql[i];
    pParse->sLastToken.n = sqlite3GetToken((unsigned char*)&zSql[i],&tokenType);
    i += pParse->sLastToken.n;

    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
    ** will take responsibility for freeing the Table structure.
    */
    sqlite3DeleteTable(db, pParse->pNewTable);
  }

  sqlite3DeleteTrigger(db, pParse->pNewTrigger);

  sqlite3DbFree(db, pParse->apVarExpr);
  sqlite3DbFree(db, pParse->aAlias);
  while( pParse->pAinc ){
    AutoincInfo *p = pParse->pAinc;
    pParse->pAinc = p->pNext;
    sqlite3DbFree(db, p);
  }
  while( pParse->pZombieTab ){

void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeDeleteObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int,int);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
  void sqlite3VdbeTrace(Vdbe*,FILE*);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);

int sqlite3VdbeReset(Vdbe*);
void sqlite3VdbeSetNumCols(Vdbe*,int);
int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
void sqlite3VdbeCountChanges(Vdbe*);
sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, int);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);

  u32 magic;              /* Magic number for sanity checking */
  char *zErrMsg;          /* Error message written here */
  Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
  Mem *aVar;              /* Values for the OP_Variable opcode. */
  char **azVar;           /* Name of variables */
  ynVar nVar;             /* Number of entries in aVar[] */

  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
  u8 errorAction;         /* Recovery action to do in case of an error */
  u8 okVar;               /* True if azVar[] has been initialized */
  u8 explain;             /* True if EXPLAIN present on SQL command */
  u8 changeCntOn;         /* True to update the change-counter */
  u8 expired;             /* True if the VM needs to be recompiled */
  u8 runOnlyOnce;         /* Automatically expire on reset */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */

  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeReset(v);
    sqlite3VdbeMakeReady(v, -1, 0, 0, 0, 0, 0);
    assert( (rc & (v->db->errMask))==rc );
    rc = sqlite3ApiExit(v->db, rc);
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

** This routine is added to support DBD::SQLite.  
*/
int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe*)pStmt;
  return p ? p->nVar : 0;
}

/*
** Create a mapping from variable numbers to variable names
** in the Vdbe.azVar[] array, if such a mapping does not already
** exist.
*/
static void createVarMap(Vdbe *p){
  if( !p->okVar ){
    int j;
    Op *pOp;
    sqlite3_mutex_enter(p->db->mutex);
    /* The race condition here is harmless.  If two threads call this
    ** routine on the same Vdbe at the same time, they both might end
    ** up initializing the Vdbe.azVar[] array.  That is a little extra
    ** work but it results in the same answer.
    */
    for(j=0, pOp=p->aOp; j<p->nOp; j++, pOp++){
      if( pOp->opcode==OP_Variable ){
        assert( pOp->p1>0 && pOp->p1<=p->nVar );
        p->azVar[pOp->p1-1] = pOp->p4.z;
      }
    }
    p->okVar = 1;
    sqlite3_mutex_leave(p->db->mutex);
  }
}

/*
** Return the name of a wildcard parameter.  Return NULL if the index
** is out of range or if the wildcard is unnamed.
**
** The result is always UTF-8.
*/
const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
  Vdbe *p = (Vdbe*)pStmt;
  if( p==0 || i<1 || i>p->nVar ){
    return 0;
  }
  createVarMap(p);
  return p->azVar[i-1];
}

/*
** Given a wildcard parameter name, return the index of the variable
** with that name.  If there is no variable with the given name,
** return 0.
*/
int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
  int i;
  if( p==0 ){
    return 0;
  }
  createVarMap(p); 
  if( zName ){
    for(i=0; i<p->nVar; i++){
      const char *z = p->azVar[i];
      if( z && memcmp(z,zName,nName)==0 && z[nName]==0 ){
        return i+1;
      }
    }
  }
  return 0;

  }else{
    *pnByte += nByte;
  }
  return pBuf;
}

/*
** 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.
**
** This function may be called more than once on a single virtual machine.
** The first call is made while compiling the SQL statement. Subsequent
** calls are made as part of the process of resetting a statement to be
** re-executed (from a call to sqlite3_reset()). The nVar, nMem, nCursor 
** and isExplain parameters are only passed correct values the first time
** the function is called. On subsequent calls, from sqlite3_reset(), nVar
** is passed -1 and nMem, nCursor and isExplain are all passed zero.
*/
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 nArg,                      /* Maximum number of args in SubPrograms */
  int isExplain,                 /* True if the EXPLAIN keywords is present */
  int usesStmtJournal            /* True to set Vdbe.usesStmtJournal */
){

  int n;
  sqlite3 *db = p->db;

  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. */
  p->magic = VDBE_MAGIC_RUN;


































































  /* For each cursor required, also allocate a memory cell. Memory
  ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
  ** the vdbe program. Instead they are used to allocate space for
  ** VdbeCursor/BtCursor structures. The blob of memory associated with 
  ** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
  ** stores the blob of memory associated with cursor 1, etc.
  **
  ** See also: allocateCursor().
  */
  nMem += nCursor;

  /* Allocate space for memory registers, SQL variables, VDBE cursors and 
  ** an array to marshal SQL function arguments in. This is only done the
  ** first time this function is called for a given VDBE, not when it is
  ** being called from sqlite3_reset() to reset the virtual machine.
  */
  if( nVar>=0 && ALWAYS(db->mallocFailed==0) ){
    u8 *zCsr = (u8 *)&p->aOp[p->nOp];       /* Memory avaliable for alloation */
    u8 *zEnd = (u8 *)&p->aOp[p->nOpAlloc];  /* First byte past available mem */
    int nByte;                              /* How much extra memory needed */

    resolveP2Values(p, &nArg);
    p->usesStmtJournal = (u8)usesStmtJournal;
    if( isExplain && nMem<10 ){
      nMem = 10;
    }
    memset(zCsr, 0, zEnd-zCsr);
    zCsr += (zCsr - (u8*)0)&7;
    assert( EIGHT_BYTE_ALIGNMENT(zCsr) );

    /* Memory for registers, parameters, cursor, etc, is allocated in two
    ** passes.  On the first pass, we try to reuse unused space at the 
    ** end of the opcode array.  If we are unable to satisfy all memory
    ** requirements by reusing the opcode array tail, then the second
    ** pass will fill in the rest using a fresh allocation.  
    **
    ** This two-pass approach that reuses as much memory as possible from
    ** the leftover space at the end of the opcode array can significantly
    ** reduce the amount of memory held by a prepared statement.
    */
    do {
      nByte = 0;
      p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
      p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
      p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
      p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
      p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                            &zCsr, zEnd, &nByte);
      if( nByte ){
        p->pFree = sqlite3DbMallocZero(db, nByte);
      }
      zCsr = p->pFree;
      zEnd = &zCsr[nByte];
    }while( nByte && !db->mallocFailed );

    p->nCursor = (u16)nCursor;
    if( p->aVar ){
      p->nVar = (ynVar)nVar;
      for(n=0; n<nVar; n++){
        p->aVar[n].flags = MEM_Null;
        p->aVar[n].db = db;
      }
    }





    if( p->aMem ){
      p->aMem--;                      /* aMem[] goes from 1..nMem */
      p->nMem = nMem;                 /*       not from 0..nMem-1 */
      for(n=1; n<=nMem; n++){
        p->aMem[n].flags = MEM_Null;
        p->aMem[n].db = db;
      }
    }
  }
#ifdef SQLITE_DEBUG
  for(n=1; n<p->nMem; n++){
    assert( p->aMem[n].db==db );
  }
#endif

  p->pc = -1;
  p->rc = SQLITE_OK;
  p->errorAction = OE_Abort;
  p->explain |= isExplain;
  p->magic = VDBE_MAGIC_RUN;
  p->nChange = 0;
  p->cacheCtr = 1;
  p->minWriteFileFormat = 255;
  p->iStatement = 0;
  p->nFkConstraint = 0;
#ifdef VDBE_PROFILE
  {
    int i;
    for(i=0; i<p->nOp; i++){
      p->aOp[i].cnt = 0;
      p->aOp[i].cycles = 0;
    }
  }
#endif
}

/*
** Close a VDBE cursor and release all the resources that cursor 
** happens to hold.
*/
void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){

** Free all memory associated with the Vdbe passed as the second argument.
** The difference between this function and sqlite3VdbeDelete() is that
** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
** the database connection.
*/
void sqlite3VdbeDeleteObject(sqlite3 *db, Vdbe *p){
  SubProgram *pSub, *pNext;

  assert( p->db==0 || p->db==db );
  releaseMemArray(p->aVar, p->nVar);
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  for(pSub=p->pProgram; pSub; pSub=pNext){
    pNext = pSub->pNext;
    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
    sqlite3DbFree(db, pSub);
  }

  vdbeFreeOpArray(db, p->aOp, p->nOp);
  sqlite3DbFree(db, p->aLabel);
  sqlite3DbFree(db, p->aColName);
  sqlite3DbFree(db, p->zSql);
  sqlite3DbFree(db, p->pFree);
  sqlite3DbFree(db, p);
}

      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){



        sqlite3VdbeMakeReady(v, 1, 1, 1, 0, 0, 0);
      }
    }
   
    pBlob->flags = flags;
    pBlob->iCol = iCol;
    pBlob->db = db;
    sqlite3BtreeLeaveAll(db);