SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.128 2004/05/26 16:54:43 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

char const *sqlite3AffinityString(char affinity){
  switch( affinity ){
    case SQLITE_AFF_INTEGER: return "i";

      FuncDef *pDef;
      int nId;
      const char *zId;
      getFunctionName(pExpr, &zId, &nId);
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList);
      /* FIX ME: The following is a temporary hack. */
      if( 0==sqlite3StrNICmp(zId, "classof", nId) ){
        assert( nExpr==1 );
        sqlite3VdbeAddOp(v, OP_Class, nExpr, 0);
      }else{
        sqlite3VdbeOp3(v, OP_Function, nExpr, 0, (char*)pDef, P3_FUNCDEF);
      }
      break;
    }
    case TK_SELECT: {
      sqlite3VdbeAddOp(v, OP_MemLoad, pExpr->iColumn, 0);
      break;
    }
    case TK_IN: {

** This file contains the C functions that implement various SQL
** functions of SQLite.  
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.58 2004/05/26 23:25:31 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "vdbeInt.h"

  mask = (int)sqlite3_user_data(context);
  iBest = 0;
  for(i=1; i<argc; i++){
    if( (sqlite3MemCompare(argv[iBest], argv[i], 0)^mask)<0 ){
      iBest = i;
    }
  }
  sqlite3_result(context, argv[iBest]);
}

/*
** Return the type of the argument.
*/
static void typeofFunc(
  sqlite3_context *context,

** Implementation of the length() function
*/
static void lengthFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const char *z;
  int len;

  assert( argc==1 );
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE3_BLOB:
    case SQLITE3_INTEGER:
    case SQLITE3_FLOAT: {
      sqlite3_result_int32(context, sqlite3_value_bytes(argv[0]));
      break;
    }
    case SQLITE3_TEXT: {
      const char *z = sqlite3_value_text(argv[0]);
      for(len=0; *z; z++){ if( (0xc0&*z)!=0x80 ) len++; }
      sqlite3_result_int32(context, len);
      break;
    }
    default: {
      sqlite3_result_null(context);
      break;
    }
  }
}

/*
** Implementation of the abs() function
*/
static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
  const char *z;
  assert( argc==1 );
  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE3_INTEGER: {
      sqlite3_result_int64(context, -sqlite3_value_int64(argv[0]));
      break;
    }
    case SQLITE3_NULL: {

  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int i;
  for(i=0; i<argc; i++){
    if( SQLITE3_NULL!=sqlite3_value_type(argv[i]) ){
      sqlite3_result(context, argv[i]);
      break;
    }
  }
}

/*
** Implementation of random().  Return a random integer.  
*/
static void randomFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int r;
  sqlite3Randomness(sizeof(r), &r);
  sqlite3_result_int32(context, r);
}

/*
** Implementation of the last_insert_rowid() SQL function.  The return
** value is the same as the sqlite3_last_insert_rowid() API function.
*/
static void last_insert_rowid(

*/
static void change_count(
  sqlite3_context *context,
  int arg,
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int32(context, sqlite3_changes(db));
}

/*
** Implementation of the last_statement_change_count() SQL function.  The
** return value is the same as the sqlite3_last_statement_changes() API
** function.
*/
static void last_statement_change_count(
  sqlite3_context *context, 
  int arg,
  sqlite3_value **argv
){
  sqlite *db = sqlite3_user_data(context);
  sqlite3_result_int32(context, sqlite3_last_statement_changes(db));
}

/*
** Implementation of the like() SQL function.  This function implements
** the build-in LIKE operator.  The first argument to the function is the
** string and the second argument is the pattern.  So, the SQL statements:
**
**       A LIKE B
**
** is implemented as like(A,B).
*/
static void likeFunc(
  sqlite3_context *context, 
  int argc, 
  sqlite3_value **argv
){
  const unsigned char *zA = sqlite3_value_text(argv[0]);
  const unsigned char *zB = sqlite3_value_text(argv[1]);
  if( zA && zB ){
    sqlite3_result_int32(context, sqlite3LikeCompare(zA, zB));
  }
}

/*
** Implementation of the glob() SQL function.  This function implements
** the build-in GLOB operator.  The first argument to the function is the
** string and the second argument is the pattern.  So, the SQL statements:
**
**       A GLOB B
**
** is implemented as glob(A,B).
*/
static void globFunc(sqlite3_context *context, int arg, sqlite3_value **argv){
  const unsigned char *zA = sqlite3_value_text(argv[0]);
  const unsigned char *zB = sqlite3_value_text(argv[1]);
  if( zA && zB ){
    sqlite3_result_int32(context, sqlite3GlobCompare(zA, zB));
  }
}

/*
** Implementation of the NULLIF(x,y) function.  The result is the first
** argument if the arguments are different.  The result is NULL if the
** arguments are equal to each other.
*/
static void nullifFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  if( sqlite3MemCompare(argv[0], argv[1], 0)!=0 ){
    sqlite3_result(context, argv[0]);
  }
}

/*
** Implementation of the VERSION(*) function.  The result is the version
** of the SQLite library that is running.
*/

  switch( sqlite3_value_type(argv[0]) ){
    case SQLITE3_NULL: {
      sqlite3_result_text(context, "NULL", 4, 0);
      break;
    }
    case SQLITE3_INTEGER:
    case SQLITE3_FLOAT: {
      sqlite3_result(context, argv[0]);
      break;
    }
    case SQLITE3_BLOB:  /*** FIX ME.  Use a BLOB encoding ***/
    case SQLITE3_TEXT: {
      int i,j,n;
      const char *zArg = sqlite3_value_text(argv[0]);
      char *z;

  if( (argc==0 || SQLITE3_NULL!=sqlite3_value_type(argv[0])) && p ){
    p->n++;
  }
}   
static void countFinalize(sqlite3_context *context){
  CountCtx *p;
  p = sqlite3_aggregate_context(context, sizeof(*p));
  sqlite3_result_int32(context, p ? p->n : 0);
}

/*
** This function tracks state information for the min() and max()
** aggregate functions.
*/
typedef struct MinMaxCtx MinMaxCtx;

    sqlite3VdbeMemCopy(pBest, pArg);
  }
}
static void minMaxFinalize(sqlite3_context *context){
  sqlite3_value *pRes;
  pRes = (sqlite3_value *)sqlite3_aggregate_context(context, sizeof(Mem));
  if( pRes->flags ){
    sqlite3_result(context, pRes);
  }
}

/*
** This function registered all of the above C functions as SQL
** functions.  This should be the only routine in this file with
** external linkage.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.82 2004/05/26 23:25:31 drh Exp $
*/
#ifndef _SQLITE_H_
#define _SQLITE_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

  sqlite3 *db,            /* Database handle */
  const void *zSql,       /* SQL statement, UTF-16 encoded */
  int nBytes,             /* Length of zSql in bytes. */
  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
);








/*
** In the SQL strings input to sqlite3_prepare() and sqlite3_prepare16(),
** one or more literals can be replace by a wildcard "?" or ":N:" where
** N is an integer.  These value of these wildcard literals can be set
** using the routines listed below.
**
** In every case, the first parameter is a pointer to the sqlite3_stmt
** structure returned from sqlite3_prepare().  The second parameter is the
** index of the wildcard.  The first "?" has an index of 1.  ":N:" wildcards
** use the index N.
**
** When the eCopy parameter is true, a copy of the value is made into
** memory obtained and managed by SQLite.  When eCopy is false, SQLite
** assumes that the value is a constant and just stores a pointer to the
** value without making a copy.
**
** The sqlite3_bind_* routine must be called before sqlite3_step() after
** an sqlite3_prepare() or sqlite3_reset().  Unbound wildcards are interpreted
** as NULL.
*/
void sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, int eCopy);
void sqlite3_bind_double(sqlite3_stmt*, int, double);
void sqlite3_bind_int(sqlite3_stmt*, int, int);
void sqlite3_bind_int64(sqlite3_stmt*, int, long long int);
void sqlite3_bind_null(sqlite3_stmt*, int);
void sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, int eCopy);
void sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int n, int eCopy);
void sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);

/*
** Return the number of columns in the result set returned by the compiled
** SQL statement. This routine returns 0 if pStmt is an SQL statement
** that does not return data (for example an UPDATE).
*/
int sqlite3_column_count(sqlite3_stmt *pStmt);

*/
int sqlite3_data_count(sqlite3_stmt *pStmt);

/*
** Values are stored in the database in one of the following fundamental
** types.
*/
#define SQLITE_INTEGER  1
#define SQLITE_FLOAT    2
#define SQLITE_TEXT     3
#define SQLITE_BLOB     4
#define SQLITE_NULL     5

/*
** The next group of routines returns information about the information
** in a single column of the current result row of a query.  In every
** case the first parameter is a pointer to the SQL statement that is being
** executed (the sqlite_stmt* that was returned from sqlite3_prepare()) and
** the second argument is the index of the column for which information 

** _int()      Return an INTEGER value in the host computer's native
**             integer representation.  This might be either a 32- or 64-bit
**             integer depending on the host.
** _int64()    Return an INTEGER value as a 64-bit signed integer.
** _text()     Return the value as UTF-8 text.
** _text16()   Return the value as UTF-16 text.
*/
void *sqlite3_column_blob(sqlite3_stmt*, int iCol)
int sqlite3_column_bytes(sqlite3_stmt*, int iCol)
int sqlite3_column_bytes16(sqlite3_stmt*, int iCol)
double sqlite3_column_double(sqlite3_stmt*, int iCol)
int sqlite3_column_int(sqlite3_stmt*, int iCol)
long long int sqlite3_column_int64(sqlite3_stmt*, int iCol)
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol)
const void *sqlite3_column_text16(sqlite3_stmt*, int iCol)
int sqlite3_column_type(sqlite3_stmt*, int iCol);

/*
** The sqlite3_finalize() function is called to delete a compiled
** SQL statement obtained by a previous call to sqlite3_prepare()
** or sqlite3_prepare16(). If the statement was executed successfully, or
** not executed at all, then SQLITE_OK is returned. If execution of the

** statement obtained by a previous call to sqlite3_prepare() or
** sqlite3_prepare16() back to it's initial state, ready to be re-executed.
** Any SQL statement variables that had values bound to them using
** the sqlite3_bind_*() API retain their values.
*/
int sqlite3_reset(sqlite3_stmt *pStmt);

/*
** Pointers to the following two opaque structures are used to communicate
** with the implementations of user-defined functions.
*/
typedef struct sqlite3_context sqlite3_context;
typedef struct Mem sqlite3_value;

/*
** The following two functions are used to add user functions or aggregates
** implemented in C to the SQL langauge interpreted by SQLite. The
** difference only between the two is that the second parameter, the
** name of the (scalar) function or aggregate, is encoded in UTF-8 for
** sqlite3_create_function() and UTF-16 for sqlite3_create_function16().
**

** The next group of routines returns information about parameters to
** a user-defined function.  Function implementations use these routines
** to access their parameters.  These routines are the same as the
** sqlite3_column_* routines except that these routines take a single
** sqlite3_value* pointer instead of an sqlite3_stmt* and an integer
** column number.
*/
void *sqlite3_value_blob(sqlite3_value*)
int sqlite3_value_bytes(sqlite3_value*)
int sqlite3_value_bytes16(sqlite3_value*)
double sqlite3_value_double(sqlite3_value*)
int sqlite3_value_int(sqlite3_value*)
long long int sqlite3_value_int64(sqlite3_value*)
const unsigned char *sqlite3_value_text(sqlite3_value*)
const void *sqlite3_value_text16(sqlite3_value*)
int sqlite3_value_type(sqlite3_value*);

/*
** Aggregate functions use the following routine to allocate
** a structure for storing their state.  The first time this routine
** is called for a particular aggregate, a new structure of size nBytes
** is allocated, zeroed, and returned.  On subsequent calls (for the

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.89 2004/05/27 01:53:56 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** If malloc() ever fails, this global variable gets set to 1.

/*
** If zNum represents an integer that will fit in 64-bits, then set
** *pValue to that integer and return true.  Otherwise return false.
*/
int sqlite3GetInt64(const char *zNum, i64 *pValue){
  if( sqlite3FitsIn64Bits(zNum) ){
    sqlite3atoi64(zNum, pValue, TEXT_Utf8);
    return 1;
  }
  return 0;
}

/* This comparison routine is what we use for comparison operations
** between numeric values in an SQL expression.  "Numeric" is a little

**
** 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 1.337 2004/05/27 01:53:56 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

#define Release(P) if((P)->flags&MEM_Dyn){ sqliteFree((P)->z); }

/*
** Convert the given stack entity into a string if it isn't one
** already. Return non-zero if a malloc() fails.
*/
#define Stringify(P, enc) \
      (!((P)->flags&(MEM_Str|MEM_Blob)) && sqlite3VdbeMemStringify(P,enc))


/*
** Convert the given stack entity into a string that has been obtained
** from sqliteMalloc().  This is different from Stringify() above in that
** Stringify() will use the NBFS bytes of static string space if the string
** will fit but this routine always mallocs for space.
** Return non-zero if we run out of memory.

    case SQLITE_AFF_TEXT:
      /* Only attempt the conversion if there is an integer or real
      ** representation (blob and NULL do not get converted) but no string
      ** representation.
      */
      if( 0==(pRec->flags&MEM_Str) && (pRec->flags&(MEM_Real|MEM_Int)) ){
        Stringify(pRec, enc);
      }
      pRec->flags &= ~(MEM_Real|MEM_Int);

      break;

    case SQLITE_AFF_NONE:
      /* Affinity NONE. Do nothing. */

  if( zData ){
    pMem->z = &zData[offset];
    pMem->n = amt;
    pMem->flags = MEM_Blob|MEM_Ephem;
  }else{
    int rc;
    if( amt>NBFS ){
      zData = (char *)sqliteMallocRaw(amt);
      if( !zData ){
        return SQLITE_NOMEM;
      }
      pMem->flags = MEM_Blob|MEM_Dyn;
    }else{
      zData = &(pMem->zShort[0]);
      pMem->flags = MEM_Blob|MEM_Short;
    }
    pMem->z = zData;



    if( key ){
      rc = sqlite3BtreeKey(pCur, offset, amt, zData);
    }else{
      rc = sqlite3BtreeData(pCur, offset, amt, zData);
    }


    if( rc!=SQLITE_OK ){
      if( amt>NBFS ){
        sqliteFree(zData);
      }
      return rc;
    }
  }

    return SQLITE_ERROR;
  }else{
    p->rc = SQLITE_OK;
    return SQLITE_DONE;
  }
}

/* Opcode: String * * P3
**
** The string value P3 is pushed onto the stack.  If P3==0 then a
** NULL is pushed onto the stack.
*/
/* Opcode: Real * * P3
**
** The string value P3 is converted to a real and pushed on to the stack.
*/
/* Opcode: Integer P1 * P3
**
** The integer value P1 is pushed onto the stack.  If P3 is not zero
** then it is assumed to be a string representation of the same integer.
** If P1 is zero and P3 is not zero, then the value is derived from P3.
*/
case OP_Integer:
case OP_Real:
case OP_String: {
  char *z = pOp->p3;
  u8 op = pOp->opcode;

  pTos++;
  pTos->flags = 0;
 
  /* If this is an OP_Real or OP_Integer opcode, set the pTos->r or pTos->i
  ** values respectively.
  */
  if( op==OP_Real ){
    assert( z );
    assert( sqlite3IsNumber(z, 0, TEXT_Utf8) );
    pTos->r = sqlite3AtoF(z, 0);
    pTos->flags = MEM_Real;
  }else if( op==OP_Integer ){
    pTos->flags = MEM_Int;
    pTos->i = pOp->p1;
    if( pTos->i==0 && pOp->p3 ){


      sqlite3GetInt64(pOp->p3, &pTos->i);



    }

  }

  if( z ){
    /* FIX ME: For now the code in expr.c always puts UTF-8 in P3. It
    ** should transform text to the native encoding before doing so.



    */
    if( db->enc!=TEXT_Utf8 ){
      rc = sqlite3utfTranslate(z, -1, TEXT_Utf8, (void **)&pTos->z, 

          &pTos->n, db->enc);
      if( rc!=SQLITE_OK ){
        assert( !pTos->z );
        goto abort_due_to_error;
      }
      pTos->flags |= MEM_Str | MEM_Dyn | MEM_Term;
    }else{
      pTos->z = z;
      pTos->n = strlen(z) + 1;
      pTos->flags |= MEM_Str | MEM_Static | MEM_Term;


    }






  }else if( op==OP_String ){

    pTos->flags = MEM_Null;
  }




  break;
}

/* Opcode: Variable P1 * *
**
** Push the value of variable P1 onto the stack.  A variable is
** an unknown in the original SQL string as handed to sqlite3_compile().

  pTos++;
  memcpy(pTos, pFrom, sizeof(*pFrom)-NBFS);
  if( pTos->flags & (MEM_Str|MEM_Blob) ){
    if( pOp->p2 && (pTos->flags & (MEM_Dyn|MEM_Ephem)) ){
      pTos->flags &= ~MEM_Dyn;
      pTos->flags |= MEM_Ephem;
    }else if( pTos->flags & MEM_Short ){
      memcpy(pTos->zShort, pFrom->zShort, pTos->n);
      pTos->z = pTos->zShort;
    }else if( (pTos->flags & MEM_Static)==0 ){
      pTos->z = sqliteMallocRaw(pFrom->n);
      if( sqlite3_malloc_failed ) goto no_mem;
      memcpy(pTos->z, pFrom->z, pFrom->n);

      pTos->flags &= ~(MEM_Static|MEM_Ephem|MEM_Short);
      pTos->flags |= MEM_Dyn;
    }
  }
  break;
}

/* Opcode: Pull P1 * *
**

*/
case OP_Callback: {
  int i;
  assert( p->nResColumn==pOp->p1 );

  for(i=0; i<pOp->p1; i++){
    Mem *pVal = &pTos[0-i];
    SetEncodingFlags(pVal, db->enc);
    sqlite3VdbeMemNulTerminate(pVal);
  }

  p->resOnStack = 1;
  p->nCallback++;
  p->popStack = pOp->p1;
  p->pc = pc + 1;

    assert( j==nByte-1 );

    if( pOp->p2==0 ){
      popStack(&pTos, nField);
    }
    pTos++;
    pTos->n = j;
    pTos->flags = MEM_Str|MEM_Dyn|MEM_Term
    pTos->enc = db->enc;
    pTos->type = SQLITE3_TEXT;
    pTos->z = zNew;
  }
  break;
}

  n = pOp->p1;
  apVal = p->apArg;
  assert( apVal || n==0 );

  pArg = &pTos[1-n];
  for(i=0; i<n; i++, pArg++){
    SetEncodingFlags(pArg, db->enc);
    apVal[i] = pArg;
  }

  ctx.pFunc = (FuncDef*)pOp->p3;
  ctx.s.flags = MEM_Null;
  ctx.s.z = 0;
  ctx.isError = 0;

  }
  /* If the function returned an error, throw an exception */
  if( ctx.isError ){
    sqlite3SetString(&p->zErrMsg, 
       (pTos->flags & MEM_Str)!=0 ? pTos->z : "user function error", (char*)0);
    rc = SQLITE_ERROR;
  }

  if( pTos->flags&MEM_Str ){
    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }

  break;
}

/* Opcode: BitAnd * * *
**
** Pop the top two elements from the stack.  Convert both elements
** to integers.  Push back onto the stack the bit-wise AND of the

    if( r!=pTos->r ){
      goto mismatch;
    }
    pTos->i = i;
  }else if( pTos->flags & MEM_Str ){
    i64 v;
    if( sqlite3VdbeChangeEncoding(pTos, TEXT_Utf8)
       || sqlite3VdbeNulTerminate(pTos) ){
      goto no_mem;
    }
    if( !sqlite3atoi64(pTos->z, &v) ){
      double r;
      if( !sqlite3IsNumber(pTos->z, 0, TEXT_Utf8) ){
        goto mismatch;
      }

  int i, cnt;
  cnt = pOp->p1;
  if( cnt<0 ) cnt = -cnt;
  assert( &pTos[1-cnt] >= p->aStack );
  for(i=0; i<cnt && (pTos[1+i-cnt].flags & MEM_Null)==0; i++){}
  if( i>=cnt ) pc = pOp->p2-1;
  if( pOp->p1>0 ) popStack(&pTos, cnt);
  break;
}

/* Opcode: Class * * *
**
** Pop a single value from the top of the stack and push on one of the
** following strings, according to the storage class of the value just
** popped:
**
** "NULL", "INTEGER", "REAL", "TEXT", "BLOB"
**
** This opcode is probably temporary.
*/
case OP_Class: {
  int flags = pTos->flags;
  int i;

  struct {
    int mask;
    char * zClass;
    char * zClass16;
  } classes[] = {
    {MEM_Null, "NULL", "\0N\0U\0L\0L\0\0\0"},
    {MEM_Int, "INTEGER", "\0I\0N\0T\0E\0G\0E\0R\0\0\0"},
    {MEM_Real, "REAL", "\0R\0E\0A\0L\0\0\0"},
    {MEM_Str, "TEXT", "\0T\0E\0X\0T\0\0\0"},
    {MEM_Blob, "BLOB", "\0B\0L\0O\0B\0\0\0"}
  };

  Release(pTos);
  pTos->flags = MEM_Str|MEM_Static|MEM_Term;

  for(i=0; i<5; i++){
    if( classes[i].mask&flags ){
      switch( db->enc ){
        case TEXT_Utf8: 
          pTos->z = classes[i].zClass;
          break;
        case TEXT_Utf16be: 
          pTos->z = classes[i].zClass16;
          break;
        case TEXT_Utf16le: 
          pTos->z = &(classes[i].zClass16[1]);
          break;
        default:
          assert(0);
      }
      break;
    }
  }
  assert( i<5 );

  if( db->enc==TEXT_Utf8 ){
    pTos->n = strlen(pTos->z) + 1;
  }else{
    pTos->n = sqlite3utf16ByteLen(pTos->z, -1) + 2;
  }

  break;
}

/* Opcode: SetNumColumns P1 P2 *
**
** Before the OP_Column opcode can be executed on a cursor, this
** opcode must be called to set the number of fields in the table.

  assert( offset==nByte );

  /* Pop the consumed values off the stack and push on the new key. */
  if( addRowid||(pOp->p2==0) ){
    popStack(&pTos, nField+addRowid);
  }
  pTos++;
  pTos->flags = MEM_Blob|MEM_Dyn; /* TODO: should eventually be MEM_Blob */
  pTos->z = zKey;
  pTos->n = nByte;

  /* If P2 is non-zero, and if the key contains a NULL value, and if this
  ** was an OP_MakeIdxKey instruction, not OP_MakeKey, jump to P2.
  */
  if( pOp->p2 && containsNull && addRowid ){

      sqliteFree(pC->pData);
      pC->iKey = iKey;
      pC->nData = pTos->n;
      if( pTos->flags & MEM_Dyn ){
        pC->pData = pTos->z;
        pTos->flags = MEM_Null;
      }else{
        pC->pData = sqliteMallocRaw( pC->nData );
        if( pC->pData ){
          memcpy(pC->pData, pTos->z, pC->nData);
        }


      }
      pC->nullRow = 0;
    }else{
      rc = sqlite3BtreeInsert(pC->pCursor, zKey, nKey, pTos->z, pTos->n);
    }
    pC->recnoIsValid = 0;
    pC->deferredMoveto = 0;

  aRoot[j] = 0;
  popStack(&pTos, nRoot);
  pTos++;
  z = sqlite3BtreeIntegrityCheck(db->aDb[pOp->p2].pBt, aRoot, nRoot);
  if( z==0 || z[0]==0 ){
    if( z ) sqliteFree(z);
    pTos->z = "ok";
    pTos->n = 3;
    pTos->flags = MEM_Str | MEM_Static;
  }else{
    pTos->z = z;
    pTos->n = strlen(z) + 1;
    pTos->flags = MEM_Str | MEM_Dyn;
  }
  if( db->enc!=TEXT_Utf8 ){
    SetEncodingFlags(pTos, TEXT_Utf8);
    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }
  sqliteFree(aRoot);
  break;
}

/* Opcode: ListWrite * * *
**
** Write the integer on the top of the stack

/* Opcode: FileColumn P1 * *
**
** Push onto the stack the P1-th column of the most recently read line
** from the input file.
*/
case OP_FileColumn: {

  int i = pOp->p1;
  char *z;
  assert( i>=0 && i<p->nField );
  if( p->azField ){
    z = p->azField[i];
  }else{
    z = 0;
  }
  pTos++;
  if( z ){
    pTos->n = strlen(z) + 1;
    pTos->z = z;
    pTos->flags = MEM_Utf8 | MEM_Str | MEM_Ephem | MEM_Term;
    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }else{
    pTos->flags = MEM_Null;
  }

  break;
}

/* Opcode: MemStore P1 P2 *
**
** Write the top of the stack into memory location P1.
** P1 should be a small integer since space is allocated

  pMem = &p->aMem[i];
  Release(pMem);
  *pMem = *pTos;
  if( pMem->flags & MEM_Dyn ){
    if( pOp->p2 ){
      pTos->flags = MEM_Null;
    }else{
      pMem->z = sqliteMallocRaw( pMem->n );
      if( pMem->z==0 ) goto no_mem;
      memcpy(pMem->z, pTos->z, pMem->n);


    }
  }else if( pMem->flags & MEM_Short ){
    pMem->z = pMem->zShort;
  }
  if( pOp->p2 ){
    Release(pTos);
    pTos--;

  assert( pRec>=p->aStack );

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

  for(i=0; i<n; i++, pRec++){
      apVal[i] = pRec;
      SetEncodingFlags(pRec, db->enc);
  }
  i = pTos->i;
  assert( i>=0 && i<p->agg.nMem );
  ctx.pFunc = (FuncDef*)pOp->p3;
  pMem = &p->agg.pCurrent->aMem[i];
  ctx.s.z = pMem->zShort;  /* Space used for small aggregate contexts */
  ctx.pAgg = pMem->z;

  Release(pMem);
  *pMem = *pTos;
  if( pMem->flags & MEM_Dyn ){
    pTos->flags = MEM_Null;
  }else if( pMem->flags & MEM_Short ){
    pMem->z = pMem->zShort;
  }
  SetEncodingFlags(pMem, db->enc);
  SetEncoding(pMem, MEM_Utf8|MEM_Term);
  Release(pTos);
  pTos--;
  break;
}

/* Opcode: AggGet * P2 *
**
** Push a new entry onto the stack which is a copy of the P2-th field

  pMem = &pFocus->aMem[i];
  *pTos = *pMem;
  if( pTos->flags & (MEM_Str|MEM_Blob) ){
    pTos->flags &= ~(MEM_Dyn|MEM_Static|MEM_Short);
    pTos->flags |= MEM_Ephem;
  }
  if( pTos->flags&MEM_Str ){
    SetEncodingFlags(pTos, TEXT_Utf8);
    SetEncoding(pTos, encToFlags(db->enc)|MEM_Term);
  }
  break;
}

/* Opcode: AggNext * P2 *
**
** Make the next aggregate value the current aggregate.  The prior

        int x = pTos->flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
        assert( x!=0 );            /* Strings must define a string subtype */
        assert( (x & (x-1))==0 );  /* Only one string subtype can be defined */
        assert( pTos->z!=0 );      /* Strings must have a value */
        /* Mem.z points to Mem.zShort iff the subtype is MEM_Short */
        assert( (pTos->flags & MEM_Short)==0 || pTos->z==pTos->zShort );
        assert( (pTos->flags & MEM_Short)!=0 || pTos->z!=pTos->zShort );


      }else{
        /* Cannot define a string subtype for non-string objects */
        assert( (pTos->flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short))==0 );
      }
      /* MEM_Null excludes all other types */
      assert( (pTos->flags&(MEM_Str|MEM_Int|MEM_Real|MEM_Blob))==0
              || (pTos->flags&MEM_Null)==0 );

int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*);
int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3VdbeKeyCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeRowCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeSetEncoding(Mem *, u8);
int sqlite3VdbeMemCopy(Mem*, const Mem*);
int sqlite3VdbeMemNulTerminate(Mem *);
int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, int);
int sqlite3VdbeMemSetInt64(Mem*, long long int);
int sqlite3VdbeMemSetDouble(Mem*, double);

int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemDynamicify(Mem*);
int sqlite3VdbeMemStringify(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
int sqlite3VdbeMemRealify(Mem*);

  if( (p->flags & MEM_Blob)!=0 || sqlite3_value_text16(pVal) ){
    return ((Mem *)pVal)->n;
  }
  return 0;
}
double sqlite3_value_double(sqlite3_value *pVal){
  Mem *pMem = (Mem *)pVal;
  Realify(pMem, flagsToEnc(pMem->flags));
  return pMem->r;
}
int sqlite3_value_int(sqlite3_value *pVal){
  Mem *pMem = (Mem *)pVal;
  Integerify(pMem, flagsToEnc(pMem->flags));
  return (int)pVal->i;
}
long long int sqlite3_value_int64(sqlite3_value *pVal){
  Mem *pMem = (Mem *)pVal;
  Integerify(pMem, flagsToEnc(pMem->flags));
  return pVal->i;
}
const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
  if( pVal->flags&MEM_Null ){
    /* For a NULL return a NULL Pointer */
    return 0;
  }

  if( pVal->flags&MEM_Str ){
    /* If there is already a string representation, make sure it is in
    ** encoded in UTF-8.
    */
    SetEncoding(pVal, MEM_Utf8|MEM_Term);
  }else if( !(pVal->flags&MEM_Blob) ){
    /* Otherwise, unless this is a blob, convert it to a UTF-8 string */
    Stringify(pVal, TEXT_Utf8);
  }

  return pVal->z;
}
const void *sqlite3_value_text16(sqlite3_value* pVal){
  if( pVal->flags&MEM_Null ){
    /* For a NULL return a NULL Pointer */
    return 0;
  }

  if( pVal->flags&MEM_Str ){
    /* If there is already a string representation, make sure it is in
    ** encoded in UTF-16 machine byte order.
    */
    SetEncoding(pVal, encToFlags(TEXT_Utf16)|MEM_Term);
  }else if( !(pVal->flags&MEM_Blob) ){
    /* Otherwise, unless this is a blob, convert it to a UTF-16 string */
    Stringify(pVal, TEXT_Utf16);
  }

  return (const void *)(pVal->z);
}
int sqlite3_value_type(sqlite3_value* pVal){


  int f = ((Mem *)pVal)->flags;
  if( f&MEM_Null ){
    return SQLITE3_NULL;
  }
  if( f&MEM_Int ){
    return SQLITE3_INTEGER;
  }
  if( f&MEM_Real ){
    return SQLITE3_FLOAT;
  }
  if( f&MEM_Str ){
    return SQLITE3_TEXT;
  }
  if( f&MEM_Blob ){
    return SQLITE3_BLOB;
  }
  assert(0);

}

/**************************** sqlite3_result_  *******************************
** The following routines are used by user-defined functions to specify
** the function result.
*/
void sqlite3_result_blob(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  int eCopy
){
  assert( n>0 );
  MemSetStr(&pCtx->s, z, n, 0, eCopy);
}
void sqlite3_result_double(sqlite3_context *pCtx, double rVal){
  sqlite3VdbeMemSetDouble(&pCtx->s, rVal);
}
void sqlite3_result_error(sqlite3_context *pCtx, const char *z, int n){
  pCtx->isError = 1;
  sqlite3VdbeMemSetStr(&pCtx->s, z, n, TEXT_Utf8, 1);
}
void sqlite3_result_error16(sqlite3_context *pCtx, const void *z, int n){
  pCtx->isError = 1;
  sqlite3VdbeMemSetStr(&pCtx->s, z, n, TEXT_Utf16, 1);
}
void sqlite3_result_int32(sqlite3_context *pCtx, int iVal){
  sqlite3VdbeMemSetInt64(&pCtx->s, (i64)iVal);
}
void sqlite3_result_int64(sqlite3_context *pCtx, i64 iVal){
  sqlite3VdbeMemSetInt64(&pCtx->s, iVal);
}
void sqlite3_result_null(sqlite3_context *pCtx){
  sqilte3VdbeMemSetNull(&pCtx->s);
}
void sqlite3_result_text(
  sqlite3_context *pCtx, 
  const char *z, 
  int n,
  int eCopy
){
  MemSetStr(&pCtx->s, z, n, TEXT_Utf8, eCopy);
}
void sqlite3_result_text16(
  sqlite3_context *pCtx, 
  const void *z, 
  int n, 
  int eCopy
){
  MemSetStr(&pCtx->s, z, n, TEXT_Utf16, eCopy);
}
void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
  sqlite3VdbeMemCopy(&pCtx->s, pValue);
}


/*

  return SQLITE_OK;
}

/*
** Bind a blob value to an SQL statement variable.
*/
int sqlite3_bind_blob(
  sqlite3_stmt *p, 
  int i, 
  const void *zData, 
  int nData, 
  int eCopy
){
  Vdbe *p = (Vdbe *)pStmt;
  Mem *pVar;
  int rc;

  rc = vdbeUnbind(p, i);
  if( rc ){
    return rc;
  }
  pVar = &p->apVar[i-1];
  rc = sqlite3VdbeMemSetStr(pVar, zData, nData, 0, eCopy);
  return rc;
}
int sqlite3_bind_double(sqlite3_stmt *pStmt, int i, double rValue){
  int rc;
  Vdbe *p = (Vdbe *)pStmt;
  Mem *pVar;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3VdbeMemSetReal(&p->apVar[i-1], rValue);
  }
  return SQLITE_OK;
}
int sqlite3_bind_int(sqlite3_stmt *p, int i, int iValue){
  return sqlite3_bind_int64(p, i, (long long int)iValue);
}
int sqlite3_bind_int64(sqlite3_stmt *pStmt, int i, long long int iValue){
  int rc;
  Vdbe *p = (Vdbe *)pStmt;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3VdbeMemSetInt(&p->apVar[i-1], iValue);
  }
  return rc;
}
int sqlite3_bind_null(sqlite3_stmt* p, int i){
  return vdbeUnbind((Vdbe *)p, i);
}
int sqlite3_bind_text( 

    return rc;
  }
  pVar = &p->apVar[i-1];
  rc = sqlite3VdbeMemSetStr(pVar, zData, nData, TEXT_Utf8, eCopy);
  if( rc ){
    return rc;
  }
  rc = sqlite3VdbeSetEncoding(pVar, p->db->enc);
  return rc;
}
int sqlite3_bind_text16(
  sqlite3_stmt *pStmt, 
  int i, 
  const void *zData, 
  int nData, 
  int eCopy
){
  Vdbe *p = (Vdbe *)pStmt;
  Mem *pVar;
  int rc;

  rc = vdbeUnbind(p, i);
  if( rc ){
    return rc;
  }
  Mem *pVar = &p->apVar[i-1];

  /* There may or may not be a byte order mark at the start of the UTF-16.
  ** Either way set 'txt_enc' to the TEXT_Utf16* value indicating the 
  ** actual byte order used by this string. If the string does happen
  ** to contain a BOM, then move zData so that it points to the first
  ** byte after the BOM.
  */
  txt_enc = sqlite3UtfReadBom(zData, nData);
  if( txt_enc ){
    zData = (void *)(((u8 *)zData) + 2);
    nData -= 2;
  }else{
    txt_enc = SQLITE3_BIGENDIAN?TEXT_Utf16be:TEXT_Utf16le;
  }
  rc = sqlite3VdbeMemSetStr(pVar, zData, nData, txt_enc, eCopy);
  if( rc ){
    return rc;
  }
  rc = sqlite3VdbeSetEncoding(pVar, p->db->enc);
  return rc;
}

    }
    rc = SQLITE_ERROR;
    sqlite3SetString(&p->zErrMsg, sqlite3_error_string(p->rc), (char*)0);
  }else{
    Op *pOp = &p->aOp[i];
    Mem *pMem = p->aStack;
    pMem->flags = MEM_Int;
    pMem->type = SQLITE3_INT;
    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 = SQLITE3_TEXT;
    pMem->enc = TEXT_Utf8;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->i = pOp->p1;                          /* P1 */
    pMem->type = SQLITE3_INT;
    pMem++;

    pMem->flags = MEM_Int;
    pMem->i = pOp->p2;                          /* P2 */
    pMem->type = SQLITE_INT;
    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 = TEXT_Utf8;

    p->nResColumn = 5;
    p->pTos = pMem;
    p->rc = SQLITE_OK;
    p->resOnStack = 1;
    rc = SQLITE_ROW;

    for(i=0; i<p->nResColumn; i++){
      p->aColName[i].flags = MEM_Null;
    }
  }

  pColName = &(p->aColName[idx]);
  if( N==0 ){
    rc = MemSetStr(pColName, zName, -1, TEXT_Utf8, 1);
  }else{
    rc = MemSetStr(pColName, zName, N, TEXT_Utf8, N>0);
  }
  if( rc==SQLITE_OK && N==P3_DYNAMIC ){
    pColName->flags = (pColName->flags&(~MEM_Static))|MEM_Dyn;
  }
  return rc;
}

** desiredEnc.
**
** SQLITE_OK is returned if the conversion is successful (or not required).
** SQLITE_NOMEM may be returned if a malloc() fails during conversion
** between formats.
*/
int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
  u8 oldEnd;    /* 

  /* If this is not a string, or if it is a string but the encoding is
  ** already correct, do nothing. */
  if( !(pMem->flags&MEM_Str) || pMem->enc==desiredEnc ){
    return SQLITE_OK;
  }

  if( pMem->enc==TEXT_Utf8 || desiredEnd==TEXT_Utf8 ){
    /* If the current encoding does not match the desired encoding, then
    ** we will need to do some translation between encodings.
    */
    char *z;
    int n;
    int rc = sqlite3utfTranslate(pMem->z, pMem->n, pMem->enc,
                                 (void **)&z, &n, desiredEnd);
    if( rc!=SQLITE_OK ){
      return rc;
    }
  
    /* Result of sqlite3utfTranslate is currently always dynamically
    ** allocated and nul terminated. This might be altered as a performance
    ** enhancement later.
    */
    pMem->z = z;
    pMem->n = n;
    pMem->flags &= ~(MEM_Ephem | MEM_Short | MEM_Static);
    pMem->flags |= MEM_Str | MEM_Dyn | MEM_Term;
  }else{
    /* Must be translating between UTF-16le and UTF-16be. */
    int i;
    u8 *pFrom, *pTo;
    sqlite3VdbeMemMakeWritable(pMem);
    for(i=0, pFrom=pMem->z, pTo=&pMem->z[1]; i<pMem->n; i+=2, pFrom++, pTo++){
      u8 temp = *pFrom;
      *pFrom = *pTo;
      *pTo = temp;
    }
  }
  pMem->enc = desiredEnc;
  return SQLITE_OK;
}

/*
** Make the given Mem object MEM_Dyn.
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemMakeDynamicify(Mem *pMem){
  int n;
  u8 *z;
  if( (pMem->flags & (MEM_Ephem|MEM_Static|MEM_Short))==0 ){
    return SQLITE_OK;
  }
  assert( (pMem->flags & MEM_Dyn)==0 );
  assert( pMem->flags & (MEM_Str|MEM_Blob) );
  z = sqliteMallocRaw( n+2 )
  if( z==0 ){
    return SQLITE_NOMEM;
  }
  pMem->flags |= MEM_Dyn|MEM_Term;
  memcpy(z, pMem->z, n );
  z[n] = 0;
  z[n+1] = 0;
  pMem->z = z;
  pMem->flags &= ~(MEM_Ephem|MEM_Static|MEM_Short);

}

/*
** Make the given Mem object either MEM_Short or MEM_Dyn so that bytes
** of the Mem.z[] array can be modified.
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemMakeWritable(Mem *pMem){
  int n;
  u8 *z;
  if( (pMem->flags & (MEM_Ephem|MEM_Static))==0 ){
    return SQLITE_OK;
  }
  assert( (pMem->flags & MEM_Dyn)==0 );
  assert( pMem->flags & (MEM_Str|MEM_Blob) );
  if( (n = pMem->n)+2<sizeof(pMem->zShort) ){
    z = pMem->zShort;
    pMem->flags |= MEM_Short|MEM_Term;
  }else{
    z = sqliteMallocRaw( n+2 )
    if( z==0 ){
      return SQLITE_NOMEM;
    }
    pMem->flags |= MEM_Dyn|MEM_Term;
  }
  memcpy(z, pMem->z, n );
  z[n] = 0;
  z[n+1] = 0;
  pMem->z = z;
  pMem->flags &= ~(MEM_Ephem|MEM_Static);

}

/*
** Make sure the given Mem is \u0000 terminated.
*/
int sqlite3VdbeMemNulTerminate(Mem *pMem){
  if( (pMem->flags & MEM_Term)!=0 || pMem->flags & (MEM_Str|MEM_Blob))==0 ){
    return SQLITE_OK;   /* Nothing to do */
  }
  /* Only static or ephemeral strings can be unterminated */
  assert( (pMem->flags & (MEM_Static|MEM_Ephem))!=0 );
  sqlite3VdbeMemMakeWriteable(pMem);
}

/*
** Add MEM_Str to the set of representations for the given Mem.
** A NULL is converted into an empty string.  Numbers are converted
** using sqlite3_snprintf().  Converting a BLOB to a string is a
** no-op.

    if( fg & MEM_Real ){
      sqlite3_snprintf(NBFS, z, "%.15g", pMem->r);
    }else{
      assert( fg & MEM_Int );
      sqlite3_snprintf(NBFS, z, "%lld", pMem->i);
    }
    pMem->n = strlen(z);
    pMem->z = n;
    pMem->enc = TEXT_Utf8;
    pMem->flags |= MEM_Str | MEM_Short | MEM_Term;
    sqlite3VdbeMemChangeEncoding(pMem, enc);
  }
  return rc;
}










/*
** Convert the Mem to have representation MEM_Int only.  All
** prior representations are invalidated.  NULL is converted into 0.
*/
int sqlite3VdbeMemIntegerify(Mem *pMem){
  if( pMem->flags & MEM_Int ){
    /* Do nothing */
  }else if( pMem->flags & MEM_Real ){
    pMem->i = (i64)pMem->r;
  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
    if( sqlite3VdbeChangeEncoding(pMem, TEXT_Utf8)
       || sqlite3VdbeNulTerminate(pMem) ){
      return SQLITE_NOMEM;
    }
    assert( pMem->z );
    sqlite3atoi64(pMem->z, &pMem->i);
  }else{
    pMem->i = 0;
  }
  Release(pMem);
  pMem->flags = MEM_Int;
  pMem->type = SQLITE3_INTEGER;

}

/*
** Add MEM_Real to the set of representations for pMem.  Prior
** prior representations other than MEM_Null retained.  NULL is
** converted into 0.0.
*/
int sqlite3VdbeMemRealify(Mem *pMem){
  if( pMem->flags & MEM_Int ){
    pMem->r = pMem->r;
    pMem->flags |= MEM_Real;
  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
    if( sqlite3VdbeChangeEncoding(pMem, TEXT_Utf8)
       || sqlite3VdbeNulTerminate(pMem) ){
      return SQLITE_NOMEM;
    }
    assert( pMem->z );
    pMem->r = sqlite3AtoF(pMem->z, 0);
    Release(pMem);
    pMem->flags = MEM_Real;
    pMem->type = SQLITE3_INTEGER;
  }else{
    pMem->r = 0.0;
    pMem->flags = MEM_Real;
    pMem->type = SQLITE3_INTEGER;
  }
}

/*
** Release any memory held by the Mem
*/
static void releaseMem(Mem *p){
  if( p->flags & MEM_Dyn ){
    sqliteFree(p);
  }
}

/*
** Delete any previous value and set the value stored in *pMem to NULL.
*/
void sqlite3VdbeMemSetNull(Mem *pMem){
  releaseMem(pMem);

int sqlite3VdbeMemSetStr(
  Mem *pMem,          /* Memory cell to set to string value */
  const char *z,      /* String pointer */
  int n,              /* Bytes in string, or negative */
  u8 enc,             /* Encoding of z.  0 for BLOBs */
  int eCopy           /* True if this function should make a copy of z */
){
  Mem tmp;

  releaseMem(pMem);
  if( !z ){
    pMem->flags = MEM_Null;
    pMem->type = SQLITE3_NULL;
    return SQLITE_OK;
  }

      }
      break;

    default:
      assert(0);
  }
  if( eCopy ){
    sqlite3VdbeMemMakeWriteable(pMem);
  }

}

/*
** Compare the values contained by the two memory cells, returning
** negative, zero or positive if pMem1 is less than, equal to, or greater
** than pMem2. Sorting order is NULL's first, followed by numbers (integers
** and reals) sorted numerically, followed by text ordered by the collating