/*

 ** 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