engine/sqlite/src/vdbe.h
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1:5f8e5adbbed9 2:29cda98b007e
       
     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: vdbe.h 1282 2008-11-13 09:31:33Z LarsPson $
       
    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 #define P3_TRANSIENT (-9) /* P3 is a pointer to a transient string */
       
    73 #define P3_VTAB     (-10) /* P3 is a pointer to an sqlite3_vtab structure */
       
    74 #define P3_MPRINTF  (-11) /* P3 is a string obtained from sqlite3_mprintf() */
       
    75 #define P3_REAL     (-12) /* P3 is a 64-bit floating point value */
       
    76 #define P3_INT64    (-13) /* P3 is a 64-bit signed integer */
       
    77 
       
    78 /* When adding a P3 argument using P3_KEYINFO, a copy of the KeyInfo structure
       
    79 ** is made.  That copy is freed when the Vdbe is finalized.  But if the
       
    80 ** argument is P3_KEYINFO_HANDOFF, the passed in pointer is used.  It still
       
    81 ** gets freed when the Vdbe is finalized so it still should be obtained
       
    82 ** from a single sqliteMalloc().  But no copy is made and the calling
       
    83 ** function should *not* try to free the KeyInfo.
       
    84 */
       
    85 #define P3_KEYINFO_HANDOFF (-9)
       
    86 
       
    87 /*
       
    88 ** The Vdbe.aColName array contains 5n Mem structures, where n is the 
       
    89 ** number of columns of data returned by the statement.
       
    90 */
       
    91 #define COLNAME_NAME     0
       
    92 #define COLNAME_DECLTYPE 1
       
    93 #define COLNAME_DATABASE 2
       
    94 #define COLNAME_TABLE    3
       
    95 #define COLNAME_COLUMN   4
       
    96 #define COLNAME_N        5      /* Number of COLNAME_xxx symbols */
       
    97 
       
    98 /*
       
    99 ** The following macro converts a relative address in the p2 field
       
   100 ** of a VdbeOp structure into a negative number so that 
       
   101 ** sqlite3VdbeAddOpList() knows that the address is relative.  Calling
       
   102 ** the macro again restores the address.
       
   103 */
       
   104 #define ADDR(X)  (-1-(X))
       
   105 
       
   106 /*
       
   107 ** The makefile scans the vdbe.c source file and creates the "opcodes.h"
       
   108 ** header file that defines a number for each opcode used by the VDBE.
       
   109 */
       
   110 #include "opcodes.h"
       
   111 
       
   112 /*
       
   113 ** Prototypes for the VDBE interface.  See comments on the implementation
       
   114 ** for a description of what each of these routines does.
       
   115 */
       
   116 Vdbe *sqlite3VdbeCreate(sqlite3*);
       
   117 int sqlite3VdbeAddOp(Vdbe*,int,int,int);
       
   118 int sqlite3VdbeOp3(Vdbe*,int,int,int,const char *zP3,int);
       
   119 int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp);
       
   120 void sqlite3VdbeChangeP1(Vdbe*, int addr, int P1);
       
   121 void sqlite3VdbeChangeP2(Vdbe*, int addr, int P2);
       
   122 void sqlite3VdbeJumpHere(Vdbe*, int addr);
       
   123 void sqlite3VdbeChangeToNoop(Vdbe*, int addr, int N);
       
   124 void sqlite3VdbeChangeP3(Vdbe*, int addr, const char *zP1, int N);
       
   125 void sqlite3VdbeUsesBtree(Vdbe*, int);
       
   126 VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
       
   127 int sqlite3VdbeMakeLabel(Vdbe*);
       
   128 void sqlite3VdbeDelete(Vdbe*);
       
   129 void sqlite3VdbeMakeReady(Vdbe*,int,int,int,int);
       
   130 int sqlite3VdbeFinalize(Vdbe*);
       
   131 void sqlite3VdbeResolveLabel(Vdbe*, int);
       
   132 int sqlite3VdbeCurrentAddr(Vdbe*);
       
   133 #ifdef SQLITE_DEBUG
       
   134   void sqlite3VdbeTrace(Vdbe*,FILE*);
       
   135 #endif
       
   136 void sqlite3VdbeResetStepResult(Vdbe*);
       
   137 int sqlite3VdbeReset(Vdbe*);
       
   138 void sqlite3VdbeSetNumCols(Vdbe*,int);
       
   139 int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, int);
       
   140 void sqlite3VdbeCountChanges(Vdbe*);
       
   141 sqlite3 *sqlite3VdbeDb(Vdbe*);
       
   142 void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
       
   143 void sqlite3VdbeSwap(Vdbe*,Vdbe*);
       
   144 
       
   145 #ifndef NDEBUG
       
   146   void sqlite3VdbeComment(Vdbe*, const char*, ...);
       
   147 # define VdbeComment(X)  sqlite3VdbeComment X
       
   148 #else
       
   149 # define VdbeComment(X)
       
   150 #endif
       
   151 
       
   152 #endif