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 1.99 2003/09/06 01:10:47 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function

    case TK_DOT:
    case TK_FUNCTION:
      return 0;
    case TK_NULL:
    case TK_STRING:
    case TK_INTEGER:
    case TK_FLOAT:
    case TK_VARIABLE:
      return 1;
    default: {
      if( p->pLeft && !sqliteExprIsConstant(p->pLeft) ) return 0;
      if( p->pRight && !sqliteExprIsConstant(p->pRight) ) return 0;
      if( p->pList ){
        int i;
        for(i=0; i<p->pList->nExpr; i++){

    case TK_GLOB:
    case TK_LIKE:
      return SQLITE_SO_NUM;

    case TK_STRING:
    case TK_NULL:
    case TK_CONCAT:
    case TK_VARIABLE:
      return SQLITE_SO_TEXT;

    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:

      sqliteVdbeChangeP3(v, addr, pExpr->token.z, pExpr->token.n);
      sqliteVdbeDequoteP3(v, addr);
      break;
    }
    case TK_NULL: {
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      break;
    }
    case TK_VARIABLE: {
      sqliteVdbeAddOp(v, OP_Variable, atoi(&pExpr->token.z[1]), 0);
      break;
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {

** 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 1.31 2003/09/06 01:10:47 drh Exp $
*/
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
#include "sqliteInt.h"
#include "os.h"

  if( p && p->z && p->z!=p->zBuf ){
    sqliteFree(p->z);
  }
}

/****************************************************************************
** Time and date functions.
**
** 1970-01-01 00:00:00 is JD 2440587.5.
** 2000-01-01 00:00:00 is JD 2451544.5
**
** SQLite processes all times and dates as Julian Day numbers.  The
** dates and times are stored as the number of days since noon
** in Greenwich on November 24, 4714 B.C. according to the Gregorian
** calendar system.
**
** This implement requires years to be expressed as a 4-digit number

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.141 2003/09/06 01:10:47 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information

  const char *zSql,           /* The SQL to be executed */
  const char **pzTail,        /* OUT: Next statement after the first */
  sqlite_vm **ppVm,           /* OUT: The virtual machine */
  char **pzErrMsg             /* OUT: Write error messages here */
){
  return sqliteMain(db, zSql, 0, 0, pzTail, ppVm, pzErrMsg);
}

/*
** If the SQL that was handed to sqlite_compile contains variables of
** the form $1, $2, $3, etc. then this routine assigns values to those
** variables.  azValue[0] is assigned to $1.  azValue[1] is assigned
** to $2.  And so forth.  The value of variable $0 will always be NULL.
** The values of any variable $N where N>nValue will be NULL.  If any
** azValue[] is a NULL pointer, then the corresponding variable will be
** NULL.
**
** This routine can only be called immediately after sqlite_compile()
** or sqlite_reset() and before any calls to sqlite_step().
**
** This routine makes copies of all strings in azValue[] so the values
** passed in can be changed or deleted immediately after this call.  The
** copies are deallocated when sqlite_finalize() or sqlite_reset() is
** invoked.
*/
int sqlite_instantiate(
  sqlite_vm *pVm,
  int nValue,
  const char **azValue
){
  return sqliteVdbeSetVariables((Vdbe*)pVm, nValue, azValue);
}


/*
** The following routine destroys a virtual machine that is created by
** the sqlite_compile() routine.
**
** The integer returned is an SQLITE_ success/failure code that describes
** the result of executing the virtual machine.  An error message is

){
  int rc = sqliteVdbeFinalize((Vdbe*)pVm, pzErrMsg);
  sqliteStrRealloc(pzErrMsg);
  return rc;
}

/*
** Terminate the current execution of a virtual machine then
** reset the virtual machine back to its starting state so that it
** can be reused.  Any error message resulting from the prior execution
** is written into *pzErrMsg.  A success code from the prior execution
** is returned.
*/
int sqlite_reset(
  sqlite_vm *pVm,            /* The virtual machine to be destroyed */
  char **pzErrMsg            /* OUT: Write error messages here */

){
  int rc = sqliteVdbeReset((Vdbe*)pVm, pzErrMsg);
  sqliteVdbeMakeReady((Vdbe*)pVm, 0, 0, 0);
  sqliteStrRealloc(pzErrMsg);
  return rc;
}

/*
** Return a static string that describes the kind of error specified in the
** argument.

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.90 2003/09/06 01:10:47 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

}

/*
** When this routine is called, the pager has the journal file open and
** a write lock on the database.  This routine releases the database
** write lock and acquires a read lock in its place.  The journal file
** is deleted and closed.
**
** TODO: Consider keeping the journal file open for temporary databases.
** This might give a performance improvement on windows where opening
** a file is an expensive operation.
*/
static int pager_unwritelock(Pager *pPager){
  int rc;
  PgHdr *pPg;
  if( pPager->state<SQLITE_WRITELOCK ) return SQLITE_OK;
  sqlitepager_ckpt_commit(pPager);
  if( pPager->ckptOpen ){

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.100 2003/09/06 01:10:48 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  if( pParse->zErrMsg==0 ){

  A = sqliteExpr(TK_DOT, temp1, temp4, 0);
}
expr(A) ::= expr(B) ORACLE_OUTER_JOIN. 
                             {A = B; ExprSetProperty(A,EP_Oracle8Join);}
expr(A) ::= INTEGER(X).      {A = sqliteExpr(TK_INTEGER, 0, 0, &X);}
expr(A) ::= FLOAT(X).        {A = sqliteExpr(TK_FLOAT, 0, 0, &X);}
expr(A) ::= STRING(X).       {A = sqliteExpr(TK_STRING, 0, 0, &X);}
expr(A) ::= VARIABLE(X).     {A = sqliteExpr(TK_VARIABLE, 0, 0, &X);}
expr(A) ::= ID(X) LP exprlist(Y) RP(E). {
  A = sqliteExprFunction(Y, &X);
  sqliteExprSpan(A,&X,&E);
}
expr(A) ::= ID(X) LP STAR RP(E). {
  A = sqliteExprFunction(0, &X);
  sqliteExprSpan(A,&X,&E);

**    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 1.51 2003/09/06 01:10:48 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++.

**
** Additionally, if ppVm is not NULL, *ppVm is left pointing to a new virtual
** machine loaded with the compiled version of the original query ready for
** execution.
**
** If sqlite_reset() returns SQLITE_SCHEMA, then *ppVm is set to NULL.
**
*/
int sqlite_reset(sqlite_vm *, char **pzErrMsg);

/*
** If the SQL that was handed to sqlite_compile contains variables of
** the form $1, $2, $3, etc. then this routine assigns values to those
** variables.  azValue[0] is assigned to $1.  azValue[1] is assigned
** to $2.  And so forth.  The value of variable $0 will always be NULL.
** The values of any variable $N where N>nValue will be NULL.  If any
** azValue[] is a NULL pointer, then the corresponding variable will be
** NULL.
**
** This routine can only be called immediately after sqlite_compile()
** or sqlite_reset() and before any calls to sqlite_step().
**
** This routine makes copies of all strings in azValue[] so the values
** passed in can be changed or deleted immediately after this call.  The
** copies are deallocated when sqlite_finalize() or sqlite_reset() is
** invoked.
**
******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
*/
int sqlite_instantiate(sqlite_vm*, int, const char**);



#ifdef __cplusplus
}  /* End of the 'extern "C"' block */
#endif

#endif /* _SQLITE_H_ */

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the printf() interface to SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.27 2003/09/06 01:10:48 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

    sprintf(zBuf, "(%d) ", rc);
    Tcl_AppendResult(interp, zBuf, zErrMsg, 0);
    sqlite_freemem(zErrMsg);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite_reset   VM 
**
** Reset a virtual machine and prepare it to be run again.
*/
static int test_reset(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  sqlite_vm *vm;
  int rc;
  char *zErrMsg = 0;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
       " VM\"", 0);
    return TCL_ERROR;
  }
  if( getVmPointer(interp, argv[1], &vm) ) return TCL_ERROR;
  rc = sqlite_reset(vm, &zErrMsg);
  if( rc ){
    char zBuf[50];
    sprintf(zBuf, "(%d) ", rc);
    Tcl_AppendResult(interp, zBuf, zErrMsg, 0);
    sqlite_freemem(zErrMsg);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:  sqlite_instantiate  VM  ARGS...
**
** Set the values of variables (ex: $1, $2, etc) in the original SQL string.
*/
static int test_instantiate(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  sqlite_vm *vm;
  int rc;
  if( argc<2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0], 
       " VM ARGS...\"", 0);
    return TCL_ERROR;
  }
  if( getVmPointer(interp, argv[1], &vm) ) return TCL_ERROR;
  rc = sqlite_instantiate(vm, argc-2, &argv[2]);
  if( rc ){
    char zBuf[50];
    sprintf(zBuf, "(%d) ", rc);
    Tcl_AppendResult(interp, zBuf, sqlite_error_string(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

/*
** Usage:    breakpoint
**
** This routine exists for one purpose - to provide a place to put a
** breakpoint with GDB that can be triggered using TCL code.  The use
** for this is when a particular test fails on (say) the 1485th iteration.

#ifdef MEMORY_DEBUG
     { "sqlite_malloc_fail",             (Tcl_CmdProc*)sqlite_malloc_fail    },
     { "sqlite_malloc_stat",             (Tcl_CmdProc*)sqlite_malloc_stat    },
#endif
     { "sqlite_compile",                 (Tcl_CmdProc*)test_compile          },
     { "sqlite_step",                    (Tcl_CmdProc*)test_step             },
     { "sqlite_finalize",                (Tcl_CmdProc*)test_finalize         },
     { "sqlite_instantiate",             (Tcl_CmdProc*)test_instantiate      },
     { "sqlite_reset",                   (Tcl_CmdProc*)test_reset            },
     { "breakpoint",                     (Tcl_CmdProc*)test_breakpoint       },
  };
  int i;

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
  }
  Tcl_LinkVar(interp, "sqlite_search_count", 
      (char*)&sqlite_search_count, TCL_LINK_INT);
  Tcl_LinkVar(interp, "sqlite_open_file_count", 
      (char*)&sqlite_open_file_count, TCL_LINK_INT);
  return TCL_OK;
}

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.61 2003/09/06 01:10:48 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*

      }
      return i;
    }
    case '[': {
      for(i=1; z[i] && z[i-1]!=']'; i++){}
      *tokenType = TK_ID;
      return i;
    }
    case '$': {
      if( !isdigit(z[1]) ) break;
      for(i=1; z[i] && isdigit(z[i]); i++){}
      *tokenType = TK_VARIABLE;
      return i;
    }
    default: {
      if( !isIdChar[*z] ){
        break;
      }
      for(i=1; isIdChar[z[i]]; i++){}
      *tokenType = sqliteKeywordCode((char*)z, i);

**
** 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 1.238 2003/09/06 01:10:48 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following

  char **azColName;   /* Becomes the 4th parameter to callbacks */
  int nCursor;        /* Number of slots in aCsr[] */
  Cursor *aCsr;       /* One element of this array for each open cursor */
  Sorter *pSort;      /* A linked list of objects to be sorted */
  FILE *pFile;        /* At most one open file handler */
  int nField;         /* Number of file fields */
  char **azField;     /* Data for each file field */
  int nVariable;          /* Number of entries in azVariable[] */
  char **azVariable;      /* Values for the OP_Variable opcode */
  char *zLine;            /* A single line from the input file */

  int nLineAlloc;         /* Number of spaces allocated for zLine */
  int magic;              /* Magic number for sanity checking */
  int nMem;               /* Number of memory locations currently allocated */
  Mem *aMem;              /* The memory locations */
  Agg agg;                /* Aggregate information */
  int nSet;               /* Number of sets allocated */
  Set *aSet;              /* An array of sets */
  int nCallback;          /* Number of callbacks invoked so far */
  Keylist *pList;         /* A list of ROWIDs */

    Sorter *pSorter = p->pSort;
    p->pSort = pSorter->pNext;
    sqliteFree(pSorter->zKey);
    sqliteFree(pSorter->pData);
    sqliteFree(pSorter);
  }
}

/*
** Delete the variables in p->azVariable[]
*/
static void ClearVariableArray(Vdbe *p){
  sqliteFree(p->azVariable);
  p->nVariable = 0;
  p->azVariable = 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 azVariable[] array.
*/
static void Cleanup(Vdbe *p){
  int i;
  PopStack(p, p->tos+1);
  closeAllCursors(p);
  if( p->aMem ){
    for(i=0; i<p->nMem; i++){

    }
    sqliteFree(p->keylistStack);
    p->keylistStackDepth = 0;
    p->keylistStack = 0;
  }
  sqliteFree(p->zErrMsg);
  p->zErrMsg = 0;
  ClearVariableArray(p);
}

/*
** Delete an entire VDBE.
*/
void sqliteVdbeDelete(Vdbe *p){
  int i;

    if( p->aOp[i].p3type==P3_DYNAMIC ){
      sqliteFree(p->aOp[i].p3);
    }
  }
  sqliteFree(p->aOp);
  sqliteFree(p->aLabel);
  sqliteFree(p->aStack);
  p->magic = VDBE_MAGIC_DEAD;
  sqliteFree(p);
}

/*
** Give a listing of the program in the virtual machine.
**
** The interface is the same as sqliteVdbeExec().  But instead of

  assert( p!=0 );
  assert( p->aStack==0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  /* Add a HALT instruction to the very end of the program.
  */
  if( p->nOp==0 || (p->aOp && p->aOp[p->nOp-1].opcode!=OP_Halt) ){
    sqliteVdbeAddOp(p, OP_Halt, 0, 0);
  }

  /* 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.
  **
  ** Allocation all the stack space we will ever need.

  p->uniqueCnt = 0;
  p->returnDepth = 0;
  p->errorAction = OE_Abort;
  p->undoTransOnError = 0;
  p->xCallback = xCallback;
  p->pCbArg = pCallbackArg;
  p->popStack =  0;
  p->explain |= isExplain;
  p->magic = VDBE_MAGIC_RUN;
#ifdef VDBE_PROFILE
  for(i=0; i<p->nOp; i++){
    p->aOp[i].cnt = 0;
    p->aOp[i].cycles = 0;
  }
#endif

  }else{
    zStack[i] = z;
    aStack[i].n = strlen(z) + 1;
    aStack[i].flags = STK_Str | STK_Static;
  }
  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 sqlite_compile().
** The first variable is $1, the second is $2, and so forth.  The
** value of the variables is determined by sqlite_instantiate().
*/
case OP_Variable: {
  int i = ++p->tos;
  if( pOp->p1>0 && pOp->p1<=p->nVariable && p->azVariable[pOp->p1-1]!=0 ){
    zStack[i] = p->azVariable[pOp->p1-1];
    aStack[i].n = strlen(zStack[i]) + 1;
    aStack[i].flags = STK_Str | STK_Static;
  }else{
    zStack[i] = 0;
    aStack[i].n = 0;
    aStack[i].flags = STK_Null;
  }
  break;
}

/* Opcode: Pop P1 * *
**
** P1 elements are popped off of the top of stack and discarded.
*/
case OP_Pop: {
  assert( p->tos+1>=pOp->p1 );

**
** If P2 is not zero, then the original entries remain on the stack
** and the new key is pushed on top.  If P2 is zero, the original
** data is popped off the stack first then the new key is pushed
** back in its place.
**
** P3 is a string that is P1 characters long.  Each character is either
** an 'n' or a 't' to indicates if the argument should be intepreted as
** numeric or text type.  The first character of P3 corresponds to the
** lowest element on the stack.  If P3 is NULL then all arguments are
** assumed to be of the numeric type.
**
** The type makes a difference in that text-type fields may not be 
** introduced by 'b' (as described in the next paragraph).  The
** first character of a text-type field must be either 'a' (if it is NULL)
** or 'c'.  Numeric fields will be introduced by 'b' if their content
** looks like a well-formed number.  Otherwise the 'a' or 'c' will be
** used.
**
** The key is a concatenation of fields.  Each field is terminated by
** a single 0x00 character.  A NULL field is introduced by an 'a' and
** is followed immediately by its 0x00 terminator.  A numeric field is
** introduced by a single character 'b' and is followed by a sequence
** of characters that represent the number such that a comparison of
** the character string using memcpy() sorts the numbers in numerical
** order.  The character strings for numbers are generated using the
** sqliteRealToSortable() function.  A text field is introduced by a
** 'c' character and is followed by the exact text of the field.  The
** use of an 'a', 'b', or 'c' character at the beginning of each field
** guarantees that NULLs sort before numbers and that numbers sort
** before text.  0x00 characters do not occur except as separators
** between fields.
**
** See also: MakeIdxKey, SortMakeKey
*/
/* Opcode: MakeIdxKey P1 P2 P3
**

  rc = SQLITE_INTERNAL;
  goto vdbe_halt;
)
}


/*
** 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.
*/
int sqliteVdbeReset(Vdbe *p, char **pzErrMsg){
  sqlite *db = p->db;
  int i;

  if( p->magic!=VDBE_MAGIC_RUN && p->magic!=VDBE_MAGIC_HALT ){
    sqliteSetString(pzErrMsg, sqlite_error_string(SQLITE_MISUSE), 0);
    return SQLITE_MISUSE;
  }
  if( p->zErrMsg ){
    if( pzErrMsg && *pzErrMsg==0 ){

        );
        vdbePrintOp(out, i, &p->aOp[i]);
      }
      fclose(out);
    }
  }
#endif
  p->magic = VDBE_MAGIC_INIT;
  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 sqliteVdbeFinalize(Vdbe *p, char **pzErrMsg){
  int rc;
  sqlite *db;

  if( p->magic!=VDBE_MAGIC_RUN && p->magic!=VDBE_MAGIC_HALT ){
    sqliteSetString(pzErrMsg, sqlite_error_string(SQLITE_MISUSE), 0);
    return SQLITE_MISUSE;
  }
  db = p->db;
  rc = sqliteVdbeReset(p, pzErrMsg);
  sqliteVdbeDelete(p);
  if( db->want_to_close && db->pVdbe==0 ){
    sqlite_close(db);
  }
  return rc;
}

/*
** Set the values of all variables.  Variable $1 in the original SQL will
** be the string azValue[0].  $2 will have the value azValue[1].  And
** so forth.  If a value is out of range (for example $3 when nValue==2)
** then its value will be NULL.
**
** This routine overrides any prior call.
*/
int sqliteVdbeSetVariables(Vdbe *p, int nValue, const char **azValue){
  int i, n;
  char *z;
  if( p->magic!=VDBE_MAGIC_RUN || p->pc!=0 || p->nVariable!=0 ){
    return SQLITE_MISUSE;
  }
  ClearVariableArray(p);
  if( nValue==0 ){
    p->nVariable = 0;
    p->azVariable = 0;
  }
  for(i=n=0; i<nValue; i++){
    if( azValue[i] ) n += strlen(azValue[i]) + 1;
  }
  p->azVariable = sqliteMalloc( sizeof(p->azVariable[0])*nValue + n );
  if( p->azVariable==0 ){
    p->nVariable = 0;
    return SQLITE_NOMEM;
  }
  z = (char*)&p->azVariable[nValue];
  for(i=0; i<nValue; i++){
    if( azValue[i]==0 ){
      p->azVariable[i] = 0;
    }else{
      p->azVariable[i] = z;
      n = strlen(azValue[i]);
      memcpy(z, azValue[i], n+1);
      z += n+1;
    }
  }
  p->nVariable = nValue;
  return SQLITE_OK;
}


#if 0
/*
** Create a new Vdbe in *pOut and populate it with the program from p. Then
** pass p to sqliteVdbeFinalize().
*/
int sqliteVdbeReset(Vdbe *p, char ** pErrMsg, Vdbe** pOut){

  if( pOut && p->rc != SQLITE_SCHEMA ){

    /* Create a new VDBE and populate it with the program used by the old
    ** VDBE. Don't copy the last instruction of the program, as this is an 
    ** OP_Halt coded by sqliteVdbeMakeReady(). 
    */
    *pOut = sqliteVdbeCreate( p->db );
    (*pOut)->aOp = p->aOp;
    (*pOut)->nOp = p->nOp-1;
    (*pOut)->nOpAlloc = p->nOpAlloc;
    sqliteVdbeMakeReady( *pOut, p->xCallback, p->pCbArg, (int)p->explain );
    p->aOp = 0;
    p->nOp = 0;
    p->nOpAlloc = 0;
  }else if( pOut ){
    *pOut = NULL;
  }
  return sqliteVdbeFinalize(p, pErrMsg);
}
#endif

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.67 2003/09/06 01:10:49 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines

int sqliteVdbeExec(Vdbe*);
int sqliteVdbeList(Vdbe*);
int sqliteVdbeFinalize(Vdbe*,char**);
void sqliteVdbeResolveLabel(Vdbe*, int);
int sqliteVdbeCurrentAddr(Vdbe*);
void sqliteVdbeTrace(Vdbe*,FILE*);
void sqliteVdbeCompressSpace(Vdbe*,int);
int sqliteVdbeReset(Vdbe*,char **);
int sqliteVdbeSetVariables(Vdbe*,int,const char**);

#endif