SQLite

  statGet,         /* xSFunc */
  0,               /* xFinalize */
  0, 0,            /* xValue, xInverse */
  "stat_get",      /* zName */
  {0}
};

static void callStatGet(Parse *pParse, int regStat4, int iParam, int regOut){

#ifdef SQLITE_ENABLE_STAT4
  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Integer, iParam, regStat4+1);
#elif SQLITE_DEBUG
  assert( iParam==STAT_GET_STAT1 );
#else
  UNUSED_PARAMETER( iParam );
#endif
  assert( regOut!=regStat4 && regOut!=regStat4+1 );
  sqlite3VdbeAddFunctionCall(pParse, 0, regStat4, regOut, 1+IsStat4,
                             &statGetFuncdef, 0);

}

/*
** Generate code to do an analysis of all indices associated with
** a single table.
*/
static void analyzeOneTable(

    ** The third argument is only used for STAT4
    */
#ifdef SQLITE_ENABLE_STAT4
    sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3);
#endif
    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1);
    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2);
    sqlite3VdbeAddFunctionCall(pParse, 0, regStat4+1, regStat4, 2+IsStat4,
                               &statInitFuncdef, 0);


    /* Implementation of the following:
    **
    **   Rewind csr
    **   if eof(csr) goto end_of_scan;
    **   regChng = 0
    **   goto next_push_0;

        VdbeComment((v, "%s", pTab->aCol[pPk->aiColumn[j]].zName));
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
      sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
    }
#endif
    assert( regChng==(regStat4+1) );
    sqlite3VdbeAddFunctionCall(pParse, 1, regStat4, regTemp, 2+IsStat4,
                               &statPushFuncdef, 0);

    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);

    /* Add the entry to the stat1 table. */
    callStatGet(pParse, regStat4, STAT_GET_STAT1, regStat1);
    assert( "BBB"[0]==SQLITE_AFF_TEXT );
    sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regTemp, "BBB", 0);
    sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regTemp, regNewRowid);
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
    sqlite3VdbeChangeP4(v, -1, (char*)pStat1, P4_TABLE);
#endif

      int addrNext;
      int addrIsNull;
      u8 seekOp = HasRowid(pTab) ? OP_NotExists : OP_NotFound;

      pParse->nMem = MAX(pParse->nMem, regCol+nCol);

      addrNext = sqlite3VdbeCurrentAddr(v);
      callStatGet(pParse, regStat4, STAT_GET_ROWID, regSampleRowid);
      addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regSampleRowid);
      VdbeCoverage(v);
      callStatGet(pParse, regStat4, STAT_GET_NEQ, regEq);
      callStatGet(pParse, regStat4, STAT_GET_NLT, regLt);
      callStatGet(pParse, regStat4, STAT_GET_NDLT, regDLt);
      sqlite3VdbeAddOp4Int(v, seekOp, iTabCur, addrNext, regSampleRowid, 0);
      VdbeCoverage(v);
      for(i=0; i<nCol; i++){
        sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iTabCur, i, regCol+i);
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regCol, nCol, regSample);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regTabname, 6, regTemp);

  regArgs = sqlite3GetTempRange(pParse, 4);
  sqlite3ExprCode(pParse, pFilename, regArgs);
  sqlite3ExprCode(pParse, pDbname, regArgs+1);
  sqlite3ExprCode(pParse, pKey, regArgs+2);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddFunctionCall(pParse, 0, regArgs+3-pFunc->nArg, regArgs+3,


                               pFunc->nArg, pFunc, 0);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).
    */
    sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH));
  }
  

          sqlite3VdbeAddOp3(v, OP_Offset, pArg->iTable, pArg->iColumn, target);
        }else{
          sqlite3VdbeAddOp2(v, OP_Null, 0, target);
        }
      }else
#endif
      {

        sqlite3VdbeAddFunctionCall(pParse, constMask, r1, target, nFarg,

                                   pDef, pParse->iSelfTab);
      }
      if( nFarg && constMask==0 ){
        sqlite3ReleaseTempRange(pParse, r1, nFarg);
      }
      return target;
    }
#ifndef SQLITE_OMIT_SUBQUERY

    if( newMax < (unsigned)pOp->p3 ) newMax = (unsigned)pOp->p3;
  }
  pOut->u.i = sqlite3BtreeMaxPageCount(pBt, newMax);
  break;
}
#endif

/* Opcode: Function P1 P2 P3 P4 *
** Synopsis: r[P3]=func(r[P2@P5])
**
** Invoke a user function (P4 is a pointer to an sqlite3_context object that
** contains a pointer to the function to be run) with arguments taken
** from register P2 and successors.  The number of arguments is in
** the sqlite3_context object that P4 points to.
** The result of the function is stored
** in register P3.  Register P3 must not be one of the function inputs.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** See also: AggStep, AggFinal, PureFunc
*/
/* Opcode: PureFunc P1 P2 P3 P4 *
** Synopsis: r[P3]=func(r[P2@P5])
**
** Invoke a user function (P4 is a pointer to an sqlite3_context object that
** contains a pointer to the function to be run) with arguments taken
** from register P2 and successors.  The number of arguments is in
** the sqlite3_context object that P4 points to.
** The result of the function is stored
** in register P3.  Register P3 must not be one of the function inputs.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** This opcode works exactly like OP_Function.  The only difference is in
** its name.  This opcode is used in places where the function must be
** purely non-deterministic.  Some built-in date/time functions can be
** either determinitic of non-deterministic, depending on their arguments.
** When those function are used in a non-deterministic way, they will check

** to see if they were called using OP_PureFunc instead of OP_Function, and
** if they were, they throw an error.
**
** See also: AggStep, AggFinal, Function
*/

























case OP_PureFunc:              /* group */
case OP_Function: {            /* group */
  int i;
  sqlite3_context *pCtx;

  assert( pOp->p4type==P4_FUNCCTX );
  pCtx = pOp->p4.pCtx;

  /* If this function is inside of a trigger, the register array in aMem[]
  ** might change from one evaluation to the next.  The next block of code
  ** checks to see if the register array has changed, and if so it
  ** reinitializes the relavant parts of the sqlite3_context object */
  pOut = &aMem[pOp->p3];
  if( pCtx->pOut != pOut ){
    pCtx->pVdbe = p;
    pCtx->pOut = pOut;
    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
  }
  assert( pCtx->pVdbe==p );

  memAboutToChange(p, pOut);
#ifdef SQLITE_DEBUG
  for(i=0; i<pCtx->argc; i++){
    assert( memIsValid(pCtx->argv[i]) );
    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
  }

int sqlite3VdbeGoto(Vdbe*,int);
int sqlite3VdbeLoadString(Vdbe*,int,const char*);
void sqlite3VdbeMultiLoad(Vdbe*,int,const char*,...);
int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
int sqlite3VdbeAddOp4Dup8(Vdbe*,int,int,int,int,const u8*,int);
int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
int sqlite3VdbeAddFunctionCall(Parse*,int,int,int,int,const FuncDef*,int);
void sqlite3VdbeEndCoroutine(Vdbe*,int);
#if defined(SQLITE_DEBUG) && !defined(SQLITE_TEST_REALLOC_STRESS)
  void sqlite3VdbeVerifyNoMallocRequired(Vdbe *p, int N);
  void sqlite3VdbeVerifyNoResultRow(Vdbe *p);
#else
# define sqlite3VdbeVerifyNoMallocRequired(A,B)
# define sqlite3VdbeVerifyNoResultRow(A)

*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.) 
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/* Forward references */
static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef);
static void vdbeFreeOpArray(sqlite3 *, Op *, int);

/*
** Create a new virtual database engine.
*/
Vdbe *sqlite3VdbeCreate(Parse *pParse){
  sqlite3 *db = pParse->db;
  Vdbe *p;
  p = sqlite3DbMallocRawNN(db, sizeof(Vdbe) );

  const char *zP4,    /* The P4 operand */
  int p4type          /* P4 operand type */
){
  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
  return addr;
}

/*
** Add an OP_Function or OP_PureFunc opcode.
**
** The eCallCtx argument is information (typically taken from Expr.op2)
** that describes the calling context of the function.  0 means a general
** function call.  NC_IsCheck means called by a check constraint,
** NC_IdxExpr means called as part of an index expression.  NC_PartIdx
** means in the WHERE clause of a partial index.  NC_GenCol means called
** while computing a generated column value.  0 is the usual case.
*/
int sqlite3VdbeAddFunctionCall(
  Parse *pParse,        /* Parsing context */
  int p1,               /* Constant argument mask */
  int p2,               /* First argument register */
  int p3,               /* Register into which results are written */
  int nArg,             /* Number of argument */
  const FuncDef *pFunc, /* The function to be invoked */
  int eCallCtx          /* Calling context */
){
  Vdbe *v = pParse->pVdbe;
  int nByte;
  int addr;
  sqlite3_context *pCtx;
  assert( v );
  nByte = sizeof(*pCtx) + (nArg-1)*sizeof(sqlite3_value*);
  pCtx = sqlite3DbMallocRawNN(pParse->db, nByte);
  if( pCtx==0 ){
    assert( pParse->db->mallocFailed );
    freeEphemeralFunction(pParse->db, (FuncDef*)pFunc);
    return 0;
  }
  pCtx->pOut = 0;
  pCtx->pFunc = (FuncDef*)pFunc;
  pCtx->pVdbe = v;
  pCtx->isError = 0;
  pCtx->argc = nArg;
  addr = sqlite3VdbeAddOp4(v, eCallCtx ? OP_PureFunc : OP_Function,
                           p1, p2, p3, (char*)pCtx, P4_FUNCCTX);
  pCtx->iOp = addr;
  return addr;
}

/*
** Add an opcode that includes the p4 value with a P4_INT64 or
** P4_REAL type.
*/
int sqlite3VdbeAddOp4Dup8(
  Vdbe *p,            /* Add the opcode to this VM */

*/
static void freeEphemeralFunction(sqlite3 *db, FuncDef *pDef){
  if( (pDef->funcFlags & SQLITE_FUNC_EPHEM)!=0 ){
    sqlite3DbFreeNN(db, pDef);
  }
}



/*
** Delete a P4 value if necessary.
*/
static SQLITE_NOINLINE void freeP4Mem(sqlite3 *db, Mem *p){
  if( p->szMalloc ) sqlite3DbFree(db, p->zMalloc);
  sqlite3DbFreeNN(db, p);
}
static SQLITE_NOINLINE void freeP4FuncCtx(sqlite3 *db, sqlite3_context *p){
  freeEphemeralFunction(db, p->pFunc);
  sqlite3DbFreeNN(db, p);
}
static void freeP4(sqlite3 *db, int p4type, void *p4){
  assert( db );
  switch( p4type ){
    case P4_FUNCCTX: {
      freeP4FuncCtx(db, (sqlite3_context*)p4);
      break;

      break;
    }
    case P4_FUNCDEF: {
      FuncDef *pDef = pOp->p4.pFunc;
      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
      break;
    }

    case P4_FUNCCTX: {
      FuncDef *pDef = pOp->p4.pCtx->pFunc;
      sqlite3_str_appendf(&x, "%s(%d)", pDef->zName, pDef->nArg);
      break;
    }

    case P4_INT64: {
      sqlite3_str_appendf(&x, "%lld", *pOp->p4.pI64);
      break;
    }
    case P4_INT32: {
      sqlite3_str_appendf(&x, "%d", pOp->p4.i);
      break;

** features such as 'now'.
*/
int sqlite3NotPureFunc(sqlite3_context *pCtx){
#ifdef SQLITE_ENABLE_STAT4
  if( pCtx->pVdbe==0 ) return 1;
#endif
  if( pCtx->pVdbe->aOp[pCtx->iOp].opcode==OP_PureFunc ){
#if 0
    char *zMsg = sqlite3_mprintf(
       "non-deterministic use of %s() in an index, CHECK constraint, "
       "or generated column", pCtx->pFunc->zName);
    sqlite3_result_error(pCtx, zMsg, -1);
    sqlite3_free(zMsg);
#else
    sqlite3_result_error(pCtx, 
       "non-deterministic function in index expression or CHECK constraint",
       -1);
#endif
    return 0;
  }
  return 1;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*