sqlite3/vdbe.h

   1 /*
   2 ** 2001 September 15
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 *************************************************************************
  12 ** Header file for the Virtual DataBase Engine (VDBE)
  13 **
  14 ** This header defines the interface to the virtual database engine
  15 ** or VDBE.  The VDBE implements an abstract machine that runs a
  16 ** simple program to access and modify the underlying database.
  17 **
  18 ** $Id$
  19 */
  20 #ifndef _SQLITE_VDBE_H_
  21 #define _SQLITE_VDBE_H_
  22 #include <stdio.h>
  23
  24 /*
  25 ** A single VDBE is an opaque structure named "Vdbe".  Only routines
  26 ** in the source file sqliteVdbe.c are allowed to see the insides
  27 ** of this structure.
  28 */
  29 typedef struct Vdbe Vdbe;
  30
  31 /*
  32 ** A single instruction of the virtual machine has an opcode
  33 ** and as many as three operands.  The instruction is recorded
  34 ** as an instance of the following structure:
  35 */
  36 struct VdbeOp {
  37   u8 opcode;          /* What operation to perform */
  38   int p1;             /* First operand */
  39   int p2;             /* Second parameter (often the jump destination) */
  40   char *p3;           /* Third parameter */
  41   int p3type;         /* One of the P3_xxx constants defined below */
  42 #ifdef VDBE_PROFILE
  43   int cnt;            /* Number of times this instruction was executed */
  44   long long cycles;   /* Total time spend executing this instruction */
  45 #endif
  46 };
  47 typedef struct VdbeOp VdbeOp;
  48
  49 /*
  50 ** A smaller version of VdbeOp used for the VdbeAddOpList() function because
  51 ** it takes up less space.
  52 */
  53 struct VdbeOpList {
  54   u8 opcode;          /* What operation to perform */
  55   signed char p1;     /* First operand */
  56   short int p2;       /* Second parameter (often the jump destination) */
  57   char *p3;           /* Third parameter */
  58 };
  59 typedef struct VdbeOpList VdbeOpList;
  60
  61 /*
  62 ** Allowed values of VdbeOp.p3type
  63 */
  64 #define P3_NOTUSED    0   /* The P3 parameter is not used */
  65 #define P3_DYNAMIC  (-1)  /* Pointer to a string obtained from sqliteMalloc() */
  66 #define P3_STATIC   (-2)  /* Pointer to a static string */
  67 #define P3_COLLSEQ  (-4)  /* P3 is a pointer to a CollSeq structure */
  68 #define P3_FUNCDEF  (-5)  /* P3 is a pointer to a FuncDef structure */
  69 #define P3_KEYINFO  (-6)  /* P3 is a pointer to a KeyInfo structure */
  70 #define P3_VDBEFUNC (-7)  /* P3 is a pointer to a VdbeFunc structure */
  71 #define P3_MEM      (-8)  /* P3 is a pointer to a Mem*    structure */
  72
  73 /* When adding a P3 argument using P3_KEYINFO, a copy of the KeyInfo structure
  74 ** is made.  That copy is freed when the Vdbe is finalized.  But if the
  75 ** argument is P3_KEYINFO_HANDOFF, the passed in pointer is used.  It still
  76 ** gets freed when the Vdbe is finalized so it still should be obtained
  77 ** from a single sqliteMalloc().  But no copy is made and the calling
  78 ** function should *not* try to free the KeyInfo.
  79 */
  80 #define P3_KEYINFO_HANDOFF (-9)
  81
  82 /*
  83 ** The following macro converts a relative address in the p2 field
  84 ** of a VdbeOp structure into a negative number so that
  85 ** sqlite3VdbeAddOpList() knows that the address is relative.  Calling
  86 ** the macro again restores the address.
  87 */
  88 #define ADDR(X)  (-1-(X))
  89
  90 /*
  91 ** The makefile scans the vdbe.c source file and creates the "opcodes.h"
  92 ** header file that defines a number for each opcode used by the VDBE.
  93 */
  94 #include "opcodes.h"
  95
  96 /*
  97 ** Prototypes for the VDBE interface.  See comments on the implementation
  98 ** for a description of what each of these routines does.
  99 */
 100 Vdbe *sqlite3VdbeCreate(sqlite3*);
 101 void sqlite3VdbeCreateCallback(Vdbe*, int*);
 102 int sqlite3VdbeAddOp(Vdbe*,int,int,int);
 103 int sqlite3VdbeOp3(Vdbe*,int,int,int,const char *zP3,int);
 104 int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
 105 void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
 106 void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
 107 void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
 108 void sqlite3VdbeDequoteP3(Vdbe*, int addr);
 109 int sqlite3VdbeFindOp(Vdbe*, int, int, int);
 110 VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
 111 int sqlite3VdbeMakeLabel(Vdbe*);
 112 void sqlite3VdbeDelete(Vdbe*);
 113 void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int,int);
 114 int sqlite3VdbeFinalize(Vdbe*);
 115 void sqlite3VdbeResolveLabel(Vdbe*, int);
 116 int sqlite3VdbeCurrentAddr(Vdbe*);
 117 void sqlite3VdbeTrace(Vdbe*,FILE*);
 118 int sqlite3VdbeReset(Vdbe*);
 119 int sqliteVdbeSetVariables(Vdbe*,int,const char**);
 120 void sqlite3VdbeSetNumCols(Vdbe*,int);
 121 int sqlite3VdbeSetColName(Vdbe*, int, const char *, int);
 122 void sqlite3VdbeCountChanges(Vdbe*);
 123 sqlite3 *sqlite3VdbeDb(Vdbe*);
 124
 125 #ifndef NDEBUG
 126   void sqlite3VdbeComment(Vdbe*, const char*, ...);
 127 # define VdbeComment(X)  sqlite3VdbeComment X
 128 #else
 129 # define VdbeComment(X)
 130 #endif
 131
 132 #endif