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 1.44 2002/02/24 03:25:15 drh Exp $
*/
#include "sqliteInt.h"


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

        }
      }
      if( i>=pParse->nAgg ){
        i = appendAggInfo(pParse);
        if( i<0 ) return 1;
        pParse->aAgg[i].isAgg = 1;
        pParse->aAgg[i].pExpr = pExpr;
        if( pExpr->iColumn==FN_Unknown ){
          pParse->aAgg[i].pUser = sqliteFindUserFunction(pParse->db,
             pExpr->token.z, pExpr->token.n, pExpr->pList->nExpr, 0);
        }else{
          pParse->aAgg[i].pUser = 0;
        }
      }
      pExpr->iAgg = i;
      break;
    }
    default: {
      if( pExpr->pLeft ){
        nErr = sqliteExprAnalyzeAggregates(pParse, pExpr->pLeft);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.66 2002/02/24 03:25:16 drh Exp $
*/
#include "sqliteInt.h"

/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

    generateColumnNames(pParse, pTabList, pEList);
  }

  /* Reset the aggregator
  */
  if( isAgg ){
    sqliteVdbeAddOp(v, OP_AggReset, 0, pParse->nAgg);
    for(i=0; i<pParse->nAgg; i++){
      UserFunc *pUser;
      if( (pUser = pParse->aAgg[i].pUser)!=0 && pUser->xFinalize!=0 ){
        sqliteVdbeAddOp(v, OP_AggFinalizer, 0, i);
        sqliteVdbeChangeP3(v, -1, (char*)pUser->xFinalize, P3_POINTER);
      }
    }
    if( pGroupBy==0 ){
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeAddOp(v, OP_AggFocus, 0, 0);
      for(i=0; i<pParse->nAgg; i++){
        Expr *pE;
        if( !pParse->aAgg[i].isAgg ) continue;
        pE = pParse->aAgg[i].pExpr;

        sqliteExprCode(pParse, pParse->aAgg[i].pExpr);
        sqliteVdbeAddOp(v, OP_AggSet, 0, i);
      }
      sqliteVdbeResolveLabel(v, lbl1);
    }
    for(i=0; i<pParse->nAgg; i++){
      Expr *pE;
      int op, j;
      if( !pParse->aAgg[i].isAgg ) continue;
      pE = pParse->aAgg[i].pExpr;
      if( pE==0 ){
        sqliteVdbeAddOp(v, OP_AggIncr, 1, i);
        continue;
      }
      assert( pE->op==TK_AGG_FUNCTION );
      assert( pE->pList!=0 );
      for(j=0; j<pE->pList->nExpr; j++){
        sqliteExprCode(pParse, pE->pList->a[j].pExpr);
      }
      sqliteVdbeAddOp(v, OP_AggGet, 0, i);
      switch( pE->iColumn ){
        case FN_Min:      op = OP_Min;     break;
        case FN_Max:      op = OP_Max;     break;
        case FN_Avg:      op = OP_Add;     break;
        case FN_Sum:      op = OP_Add;     break;
        case FN_Unknown:  op = OP_AggFunc; break;
      }
      if( op!=OP_AggFunc ){
        sqliteVdbeAddOp(v, op, 0, 0);
      }else{
        sqliteVdbeAddOp(v, OP_AggFunc, 0, pE->pList->nExpr);
        assert( pParse->aAgg[i].pUser!=0 );
        assert( pParse->aAgg[i].pUser->xStep!=0 );
        sqliteVdbeChangeP3(v,-1,(char*)pParse->aAgg[i].pUser->xStep,P3_POINTER);
      }
      sqliteVdbeAddOp(v, OP_AggSet, 0, i);
    }
  }


  /* End the database scan loop.
  */
  sqliteWhereEnd(pWInfo);

  /* If we are processing aggregates, we need to set up a second loop
  ** over all of the aggregate values and process them.

/*
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.93 2002/02/24 03:25:16 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>

** up.  Do not try to delete the expression attached to AggExpr.pExpr.
**
** If AggExpr.pExpr==0, that means the expression is "count(*)".
*/
struct AggExpr {
  int isAgg;        /* if TRUE contains an aggregate function */
  Expr *pExpr;      /* The expression */
  UserFunc *pUser;  /* User-defined aggregate function */
};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
*/

** type to the other occurs as necessary.
** 
** Most of the code in this file is taken up by the sqliteVdbeExec()
** function which does the work of interpreting a VDBE program.
** But other routines are also provided to help in building up
** a program instruction by instruction.
**
** $Id: vdbe.c,v 1.123 2002/02/24 03:25:16 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_MoveTo or the OP_Next opcode.  The test

#define STK_Null      0x0001   /* Value is NULL */
#define STK_Str       0x0002   /* Value is a string */
#define STK_Int       0x0004   /* Value is an integer */
#define STK_Real      0x0008   /* Value is a real number */
#define STK_Dyn       0x0010   /* Need to call sqliteFree() on zStack[*] */
#define STK_Static    0x0020   /* zStack[] points to a static string */

/* The following STK_ value appears only in AggElem.aMem.s.flag fields.
** It indicates that the corresponding AggElem.aMem.z points to a
** user-defined aggregate context that needs to be finalized.
*/
#define STK_AggCtx    0x0040   /* zStack[] points to an user function context */

/*
** The "context" argument for a user-defined function.
*/
struct UserFuncContext {
  Stack s;       /* Small string, integer, and floating point values go here */
  char *z;       /* Space for holding dynamic string results */
  int isError;   /* Set to true for an error */

typedef struct Agg Agg;
typedef struct AggElem AggElem;
struct Agg {
  int nMem;            /* Number of values stored in each AggElem */
  AggElem *pCurrent;   /* The AggElem currently in focus */
  HashElem *pSearch;   /* The hash element for pCurrent */
  Hash hash;           /* Hash table of all aggregate elements */
  void (**axFinalize)(void*,void*);  /* Array of nMem finalizers */
};
struct AggElem {
  char *zKey;          /* The key to this AggElem */
  int nKey;            /* Number of bytes in the key, including '\0' at end */
  Mem aMem[1];         /* The values for this AggElem */
};

** Reset an Agg structure.  Delete all its contents.
*/
static void AggReset(Agg *pAgg){
  int i;
  HashElem *p;
  for(p = sqliteHashFirst(&pAgg->hash); p; p = sqliteHashNext(p)){
    AggElem *pElem = sqliteHashData(p);
    assert( pAgg->axFinalize!=0 );
    for(i=0; i<pAgg->nMem; i++){
      if( pElem->aMem[i].s.flags & STK_Dyn ){
        sqliteFree(pElem->aMem[i].z);
      }else if( pAgg->axFinalize[i] && (pElem->aMem[i].s.flags & STK_AggCtx) ){
        (pAgg->axFinalize[i])((void*)pElem->aMem[i].z, 0);
      }
    }
    sqliteFree(pElem);
  }
  sqliteHashClear(&pAgg->hash);
  sqliteFree(pAgg->axFinalize);
  pAgg->axFinalize = 0;
  pAgg->pCurrent = 0;
  pAgg->pSearch = 0;
  pAgg->nMem = 0;
}

/*
** Insert a new element and make it the current element.  

  "Clear",             "CreateIndex",       "CreateTable",       "IntegrityCk",
  "IdxPut",            "IdxDelete",         "IdxRecno",          "IdxGT",
  "IdxGE",             "MemLoad",           "MemStore",          "ListWrite",
  "ListRewind",        "ListRead",          "ListReset",         "SortPut",
  "SortMakeRec",       "SortMakeKey",       "Sort",              "SortNext",
  "SortCallback",      "SortReset",         "FileOpen",          "FileRead",
  "FileColumn",        "AggReset",          "AggFocus",          "AggIncr",
  "AggNext",           "AggSet",            "AggGet",            "AggFinalizer",
  "AggFunc",           "SetInsert",         "SetFound",          "SetNotFound",
  "MakeRecord",        "MakeKey",           "MakeIdxKey",        "IncrKey",
  "Goto",              "If",                "Halt",              "ColumnCount",
  "ColumnName",        "Callback",          "NullCallback",      "Integer",
  "String",            "Pop",               "Dup",               "Pull",
  "Push",              "MustBeInt",         "Add",               "AddImm",
  "Subtract",          "Multiply",          "Divide",            "Remainder",
  "BitAnd",            "BitOr",             "BitNot",            "ShiftLeft",
  "ShiftRight",        "AbsValue",          "Precision",         "Min",
  "Max",               "Like",              "Glob",              "Eq",
  "Ne",                "Lt",                "Le",                "Gt",
  "Ge",                "IsNull",            "NotNull",           "Negative",
  "And",               "Or",                "Not",               "Concat",
  "Noop",              "Strlen",            "Substr",            "UserFunc",
  "Limit",           
};

/*
** Given the name of an opcode, return its number.  Return 0 if
** there is no match.
**
** This routine is used for testing and debugging.

**
** Reset the aggregator so that it no longer contains any data.
** Future aggregator elements will contain P2 values each.
*/
case OP_AggReset: {
  AggReset(&p->agg);
  p->agg.nMem = pOp->p2;
  p->agg.axFinalize = sqliteMalloc( p->agg.nMem*sizeof(p->agg.axFinalize[0]) );
  break;
}

/* Opcode: AggFinalizer * P2 P3
**
** Register a finializer function for the P2-th column of the aggregate.
** The P3 parameter is a pointer to the finalizer.
** There should be one instance of this opcode immediately following
** each AggReset for each user defined aggregate function that is used
** in a SELECT.
**
** All finalizers must be registered so that user-defined aggregate
** function contexts can be deallocated if the VDBE aborts.
*/
case OP_AggFinalizer: {
  int i = pOp->p2;
  VERIFY( if( p->agg.nMem<=i ) goto bad_instruction; );
  p->agg.axFinalize[i] = (void(*)(void*,void*))pOp->p3;
  break;
}

/* Opcode: AggFunc * P2 P3
**
** Execute the step function for a user-defined aggregate.  The
** function has P2 arguments.  P3 is a pointer to the step function.
**
** The top of the stack should be the function context.  The P2
** parameters occur below the function context on the stack.  The
** revised function context remains on the stack after this op-code
** finishes.
*/
case OP_AggFunc: {
  int n = pOp->p2;
  int i;
  void *pCtx;
  void *(*xStep)(void*,int,const char**);

  if( aStack[p->tos].flags & STK_AggCtx ){
    pCtx = zStack[p->tos];
  }else{
    pCtx = 0;
  }
  VERIFY( if( n<=0 ) goto bad_instruction; )
  VERIFY( if( p->tos+1<n ) goto not_enough_stack; )
  for(i=p->tos-n; i<p->tos; i++){
    if( (aStack[i].flags & STK_Null)==0 ){
      if( Stringify(p, i) ) goto no_mem;
    }
  }
  xStep = (void*(*)(void*,int,const char**))pOp->p3;
  pCtx = xStep(pCtx, n, (const char**)&zStack[p->tos-n]);
  PopStack(p, n+1);
  VERIFY( NeedStack(p, p->tos+1); )
  p->tos++;
  aStack[p->tos].flags = STK_AggCtx;
  zStack[p->tos] = (char*)pCtx;
  break;
}

/* Opcode: AggFocus * P2 *
**
** Pop the top of the stack and use that as an aggregator key.  If
** an aggregator with that same key already exists, then make the

      zOld = 0;
    }
    pMem->s = aStack[tos];
    if( pMem->s.flags & STK_Dyn ){
      pMem->z = zStack[tos];
      zStack[tos] = 0;
      aStack[tos].flags = 0;
    }else if( pMem->s.flags & (STK_Static|STK_AggCtx) ){
      pMem->z = zStack[tos];
    }else if( pMem->s.flags & STK_Str ){
      pMem->z = pMem->s.z;
    }
    if( zOld ) sqliteFree(zOld);
  }
  POPSTACK;

    p->agg.pSearch = sqliteHashFirst(&p->agg.hash);
  }else{
    p->agg.pSearch = sqliteHashNext(p->agg.pSearch);
  }
  if( p->agg.pSearch==0 ){
    pc = pOp->p2 - 1;
  } else {
    int i;
    UserFuncContext ctx;
    void *pCtx;
    Mem *aMem;
    int nErr = 0;
    p->agg.pCurrent = sqliteHashData(p->agg.pSearch);
    aMem = p->agg.pCurrent->aMem;
    for(i=0; i<p->agg.nMem; i++){
      if( p->agg.axFinalize[i]==0 ) continue;
      if( (aMem[i].s.flags & STK_AggCtx)==0 ) continue;
      ctx.s.flags = STK_Null;
      ctx.z = 0;
      pCtx = (void*)aMem[i].z;
      (*p->agg.axFinalize[i])(pCtx, &ctx);
      aMem[i].s = ctx.s;
      aMem[i].z = ctx.z;
      if( (aMem[i].s.flags & STK_Str) &&
              (aMem[i].s.flags & (STK_Dyn|STK_Static))==0 ){
        aMem[i].z = aMem[i].s.z;
      }
      nErr += ctx.isError;
    }
  }
  break;
}

/* Opcode: SetInsert P1 * P3
**
** If Set P1 does not exist then create it.  Then insert value

*************************************************************************
** 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 1.46 2002/02/24 03:25:16 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

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

#define OP_AggReset           58
#define OP_AggFocus           59
#define OP_AggIncr            60
#define OP_AggNext            61
#define OP_AggSet             62
#define OP_AggGet             63
#define OP_AggFinalizer       64
#define OP_AggFunc            65

#define OP_SetInsert          66
#define OP_SetFound           67
#define OP_SetNotFound        68

#define OP_MakeRecord         69
#define OP_MakeKey            70
#define OP_MakeIdxKey         71
#define OP_IncrKey            72

#define OP_Goto               73
#define OP_If                 74
#define OP_Halt               75

#define OP_ColumnCount        76
#define OP_ColumnName         77
#define OP_Callback           78
#define OP_NullCallback       79

#define OP_Integer            80
#define OP_String             81
#define OP_Pop                82
#define OP_Dup                83
#define OP_Pull               84
#define OP_Push               85
#define OP_MustBeInt          86

#define OP_Add                87
#define OP_AddImm             88
#define OP_Subtract           89
#define OP_Multiply           90
#define OP_Divide             91
#define OP_Remainder          92
#define OP_BitAnd             93
#define OP_BitOr              94
#define OP_BitNot             95
#define OP_ShiftLeft          96
#define OP_ShiftRight         97
#define OP_AbsValue           98
#define OP_Precision          99
#define OP_Min               100
#define OP_Max               101
#define OP_Like              102
#define OP_Glob              103
#define OP_Eq                104
#define OP_Ne                105
#define OP_Lt                106
#define OP_Le                107
#define OP_Gt                108
#define OP_Ge                109
#define OP_IsNull            110
#define OP_NotNull           111
#define OP_Negative          112
#define OP_And               113
#define OP_Or                114
#define OP_Not               115
#define OP_Concat            116
#define OP_Noop              117
#define OP_Strlen            118
#define OP_Substr            119
#define OP_UserFunc          120


#define OP_Limit             121

#define OP_MAX               121

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/
Vdbe *sqliteVdbeCreate(sqlite*);
void sqliteVdbeCreateCallback(Vdbe*, int*);