/*

** 2001 September 15

**

** The author disclaims copyright to this source code.  In place of

** a legal notice, here is a blessing:

**

**    May you do good and not evil.

**    May you find forgiveness for yourself and forgive others.

**    May you share freely, never taking more than you give.

**

*************************************************************************

** 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.

**

** $Id$

*/

#ifndef _SQLITE_VDBE_H_

#define _SQLITE_VDBE_H_

#include <stdio.h>

/*

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

** in the source file sqliteVdbe.c are allowed to see the insides

** of this structure.

*/

typedef struct Vdbe Vdbe;

/*

** A single instruction of the virtual machine has an opcode

** and as many as three operands.  The instruction is recorded

** as an instance of the following structure:

*/

struct VdbeOp {

  u8 opcode;          /* What operation to perform */

  int p1;             /* First operand */

  int p2;             /* Second parameter (often the jump destination) */

  char *p3;           /* Third parameter */

  int p3type;         /* One of the P3_xxx constants defined below */

#ifdef VDBE_PROFILE

  int cnt;            /* Number of times this instruction was executed */

  long long cycles;   /* Total time spend executing this instruction */

#endif

};

typedef struct VdbeOp VdbeOp;

/*

** A smaller version of VdbeOp used for the VdbeAddOpList() function because

** it takes up less space.

*/

struct VdbeOpList {

  u8 opcode;          /* What operation to perform */

  signed char p1;     /* First operand */

  short int p2;       /* Second parameter (often the jump destination) */

  char *p3;           /* Third parameter */

};

typedef struct VdbeOpList VdbeOpList;

/*

** Allowed values of VdbeOp.p3type

*/

#define P3_NOTUSED    0   /* The P3 parameter is not used */

#define P3_DYNAMIC  (-1)  /* Pointer to a string obtained from sqliteMalloc() */

#define P3_STATIC   (-2)  /* Pointer to a static string */

#define P3_COLLSEQ  (-4)  /* P3 is a pointer to a CollSeq structure */

#define P3_FUNCDEF  (-5)  /* P3 is a pointer to a FuncDef structure */

#define P3_KEYINFO  (-6)  /* P3 is a pointer to a KeyInfo structure */

#define P3_VDBEFUNC (-7)  /* P3 is a pointer to a VdbeFunc structure */

#define P3_MEM      (-8)  /* P3 is a pointer to a Mem*    structure */

#define P3_TRANSIENT (-9) /* P3 is a pointer to a transient string */

#define P3_VTAB     (-10) /* P3 is a pointer to an sqlite3_vtab structure */

#define P3_MPRINTF  (-11) /* P3 is a string obtained from sqlite3_mprintf() */

/* When adding a P3 argument using P3_KEYINFO, a copy of the KeyInfo structure

** is made.  That copy is freed when the Vdbe is finalized.  But if the

** argument is P3_KEYINFO_HANDOFF, the passed in pointer is used.  It still

** gets freed when the Vdbe is finalized so it still should be obtained

** from a single sqliteMalloc().  But no copy is made and the calling

** function should *not* try to free the KeyInfo.

*/

#define P3_KEYINFO_HANDOFF (-9)

/*

** The Vdbe.aColName array contains 5n Mem structures, where n is the 

** number of columns of data returned by the statement.

*/

#define COLNAME_NAME     0

#define COLNAME_DECLTYPE 1

#define COLNAME_DATABASE 2

#define COLNAME_TABLE    3

#define COLNAME_COLUMN   4

#define COLNAME_N        5      /* Number of COLNAME_xxx symbols */

/*

** The following macro converts a relative address in the p2 field

** of a VdbeOp structure into a negative number so that 

** sqlite3VdbeAddOpList() knows that the address is relative.  Calling

** the macro again restores the address.

*/

#define ADDR(X)  (-1-(X))

/*

** The makefile scans the vdbe.c source file and creates the "opcodes.h"

** header file that defines a number for each opcode used by the VDBE.

*/

#include "opcodes.h"

/*

** Prototypes for the VDBE interface.  See comments on the implementation

** for a description of what each of these routines does.

*/

Vdbe *sqlite3VdbeCreate(sqlite3*);

int sqlite3VdbeAddOp(Vdbe*,int,int,int);

int sqlite3VdbeOp3(Vdbe*,int,int,int,const char *zP3,int);

int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);

void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);

void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);

void sqlite3VdbeJumpHere(Vdbe*, int addr);

void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);

void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);

void sqlite3VdbeUsesBtree(Vdbe*, int);

VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);

int sqlite3VdbeMakeLabel(Vdbe*);

void sqlite3VdbeDelete(Vdbe*);

void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int);

int sqlite3VdbeFinalize(Vdbe*);

void sqlite3VdbeResolveLabel(Vdbe*, int);

int sqlite3VdbeCurrentAddr(Vdbe*);

#ifdef SQLITE_DEBUG

  void sqlite3VdbeTrace(Vdbe*,FILE*);

#endif

void sqlite3VdbeResetStepResult(Vdbe*);

int sqlite3VdbeReset(Vdbe*);

void sqlite3VdbeSetNumCols(Vdbe*,int);

int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, int);

void sqlite3VdbeCountChanges(Vdbe*);

sqlite3 *sqlite3VdbeDb(Vdbe*);

void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);

const char *sqlite3VdbeGetSql(Vdbe*);

void sqlite3VdbeSwap(Vdbe*,Vdbe*);

#ifndef NDEBUG

  void sqlite3VdbeComment(Vdbe*, const char*, ...);

# define VdbeComment(X)  sqlite3VdbeComment X

#else

# define VdbeComment(X)

#endif

#endif