SQLite

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** This file contains C code routines used for processing expressions
**
** $Id: expr.c,v 1.15 2000/06/11 23:50:13 drh Exp $
*/
#include "sqliteInt.h"

/*
** Walk an expression tree.  Return 1 if the expression is constant
** and 0 if it involves variables.
*/

     int id;
  } aFunc[] = {
     { "count",  5, FN_Count },
     { "min",    3, FN_Min   },
     { "max",    3, FN_Max   },
     { "sum",    3, FN_Sum   },
     { "avg",    3, FN_Avg   },
     { "fcnt",   4, FN_Fcnt  },  /* Used for testing only */
  };
  int i;
  for(i=0; i<ArraySize(aFunc); i++){
    if( aFunc[i].len==pToken->n 
     && sqliteStrNICmp(pToken->z, aFunc[i].zName, aFunc[i].len)==0 ){
       return aFunc[i].id;
    }

        case FN_Avg:
        case FN_Sum: {
          no_such_func = !allowAgg;
          too_many_args = n>1;
          too_few_args = n<1;
          is_agg = 1;
          break;
        }
        /* The "fcnt(*)" function always returns the number of fetch
        ** operations that have occurred so far while processing the
        ** SQL statement.  This information can be used by test procedures
        ** to verify that indices are being used properly to minimize
        ** searching.  All arguments to fcnt() are ignored.  fcnt() has
        ** no use (other than testing) that we are aware of.
        */
        case FN_Fcnt: {
          n = 0;
          break;
        }
        default: break;
      }
      if( no_such_func ){
        sqliteSetNString(&pParse->zErrMsg, "no such function: ", -1,
           pExpr->token.z, pExpr->token.n, 0);
        pParse->nErr++;

      break;
    }
    case TK_FUNCTION: {
      int id = pExpr->iField;
      int op;
      int i;
      ExprList *pList = pExpr->pList;
      if( id==FN_Fcnt ){
        sqliteVdbeAddOp(v, OP_Fcnt, 0, 0, 0, 0);
        break;
      }
      op = id==FN_Min ? OP_Min : OP_Max;
      for(i=0; i<pList->nExpr; i++){
        sqliteExprCode(pParse, pList->a[i].pExpr);
        if( i>0 ){
          sqliteVdbeAddOp(v, op, 0, 0, 0, 0);
        }
      }

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.24 2000/06/11 23:50:13 drh Exp $
*/
#include "sqlite.h"
#include "dbbe.h"
#include "vdbe.h"
#include "parse.h"
#include <gdbm.h>
#include <stdio.h>

*/
#define FN_Unknown    0
#define FN_Count      1
#define FN_Min        2
#define FN_Max        3
#define FN_Sum        4
#define FN_Avg        5
#define FN_Fcnt       6

/*
** Forward references to structures
*/
typedef struct Column Column;
typedef struct Table Table;
typedef struct Index Index;

** inplicit conversion from one 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 1.33 2000/06/11 23:50:13 drh Exp $
*/
#include "sqliteInt.h"
#include <unistd.h>

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance

  char *zLine;        /* A single line from the input file */
  int nLineAlloc;     /* Number of spaces allocated for zLine */
  int nMem;           /* Number of memory locations currently allocated */
  Mem *aMem;          /* The memory locations */
  Agg agg;            /* Aggregate information */
  int nSet;           /* Number of sets allocated */
  Set *aSet;          /* An array of sets */
  int nFetch;         /* Number of OP_Fetch instructions executed */
};

/*
** Create a new virtual database engine.
*/
Vdbe *sqliteVdbeCreate(Dbbe *pBe){
  Vdbe *p;

**
** If any of the numeric OP_ values for opcodes defined in sqliteVdbe.h
** change, be sure to change this array to match.  You can use the
** "opNames.awk" awk script which is part of the source tree to regenerate
** this array, then copy and paste it into this file, if you want.
*/
static char *zOpName[] = { 0,
  "Open",           "Close",          "Fetch",          "Fcnt",
  "New",            "Put",            "Distinct",       "Found",
  "NotFound",       "Delete",         "Field",          "KeyAsData",
  "Key",            "Rewind",         "Next",           "Destroy",
  "Reorganize",     "ResetIdx",       "NextIdx",        "PutIdx",
  "DeleteIdx",      "MemLoad",        "MemStore",       "ListOpen",
  "ListWrite",      "ListRewind",     "ListRead",       "ListClose",
  "SortOpen",       "SortPut",        "SortMakeRec",    "SortMakeKey",
  "Sort",           "SortNext",       "SortKey",        "SortCallback",
  "SortClose",      "FileOpen",       "FileRead",       "FileField",
  "FileClose",      "AggReset",       "AggFocus",       "AggIncr",
  "AggNext",        "AggSet",         "AggGet",         "SetInsert",
  "SetFound",       "SetNotFound",    "SetClear",       "MakeRecord",
  "MakeKey",        "Goto",           "If",             "Halt",
  "ColumnCount",    "ColumnName",     "Callback",       "Integer",
  "String",         "Null",           "Pop",            "Dup",
  "Pull",           "Add",            "AddImm",         "Subtract",
  "Multiply",       "Divide",         "Min",            "Max",
  "Like",           "Glob",           "Eq",             "Ne",
  "Lt",             "Le",             "Gt",             "Ge",
  "IsNull",         "NotNull",        "Negative",       "And",
  "Or",             "Not",            "Concat",         "Noop",
};

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

            sqliteDbbeFetch(p->aTab[i].pTable, sizeof(int), 
                           (char*)&p->aStack[tos].i);
          }else{
            if( Stringify(p, tos) ) goto no_mem;
            sqliteDbbeFetch(p->aTab[i].pTable, p->aStack[tos].n, 
                           p->zStack[tos]);
          }
          p->nFetch++;
        }
        PopStack(p, 1);
        break;
      }

      /* Opcode: Fcnt * * *
      **
      ** Push an integer onto the stack which is the total number of
      ** OP_Fetch opcodes that have been executed by this virtual machine.
      **
      ** This instruction is used to implement the special fcnt() function
      ** in the SQL dialect that SQLite understands.  fcnt() is used for
      ** testing purposes.
      */
      case OP_Fcnt: {
        int i = ++p->tos;
        if( NeedStack(p, p->tos) ) goto no_mem;
        p->aStack[i].i = p->nFetch;
        p->aStack[i].flags = STK_Int;
        break;
      }

      /* Opcode: Distinct P1 P2 *
      **
      ** Use the top of the stack as a key.  If a record with that key
      ** does not exist in table P1, then jump to P2.  If the record
      ** does already exist, then fall thru.  The record is not retrieved.
      ** The key is not popped from the stack.

      ** more entries, rewind P1 and jump to location P2.
      */
      case OP_Next: {
        int i = pOp->p1;
        if( i>=0 && i<p->nTable && p->aTab[i].pTable!=0 ){
          if( sqliteDbbeNextKey(p->aTab[i].pTable)==0 ){
            pc = pOp->p2 - 1;
          }else{
            p->nFetch++;
          }
        }
        break;
      }

      /* Opcode: ResetIdx P1 * *
      **

*************************************************************************
** 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 1.10 2000/06/11 23:50:13 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

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

**
** The source tree contains an AWK script named renumberOps.awk that
** can be used to renumber these opcodes when new opcodes are inserted.
*/
#define OP_Open                1
#define OP_Close               2
#define OP_Fetch               3
#define OP_Fcnt                4
#define OP_New                 5
#define OP_Put                 6
#define OP_Distinct            7
#define OP_Found               8
#define OP_NotFound            9
#define OP_Delete             10
#define OP_Field              11
#define OP_KeyAsData          12
#define OP_Key                13
#define OP_Rewind             14
#define OP_Next               15

#define OP_Destroy            16
#define OP_Reorganize         17

#define OP_ResetIdx           18
#define OP_NextIdx            19
#define OP_PutIdx             20
#define OP_DeleteIdx          21

#define OP_MemLoad            22
#define OP_MemStore           23

#define OP_ListOpen           24
#define OP_ListWrite          25
#define OP_ListRewind         26
#define OP_ListRead           27
#define OP_ListClose          28

#define OP_SortOpen           29
#define OP_SortPut            30
#define OP_SortMakeRec        31
#define OP_SortMakeKey        32
#define OP_Sort               33
#define OP_SortNext           34
#define OP_SortKey            35
#define OP_SortCallback       36
#define OP_SortClose          37

#define OP_FileOpen           38
#define OP_FileRead           39
#define OP_FileField          40
#define OP_FileClose          41

#define OP_AggReset           42
#define OP_AggFocus           43
#define OP_AggIncr            44
#define OP_AggNext            45
#define OP_AggSet             46
#define OP_AggGet             47

#define OP_SetInsert          48
#define OP_SetFound           49
#define OP_SetNotFound        50
#define OP_SetClear           51

#define OP_MakeRecord         52
#define OP_MakeKey            53

#define OP_Goto               54
#define OP_If                 55
#define OP_Halt               56

#define OP_ColumnCount        57
#define OP_ColumnName         58
#define OP_Callback           59

#define OP_Integer            60
#define OP_String             61
#define OP_Null               62
#define OP_Pop                63
#define OP_Dup                64
#define OP_Pull               65

#define OP_Add                66
#define OP_AddImm             67
#define OP_Subtract           68
#define OP_Multiply           69
#define OP_Divide             70
#define OP_Min                71
#define OP_Max                72
#define OP_Like               73
#define OP_Glob               74
#define OP_Eq                 75
#define OP_Ne                 76
#define OP_Lt                 77
#define OP_Le                 78
#define OP_Gt                 79
#define OP_Ge                 80
#define OP_IsNull             81
#define OP_NotNull            82
#define OP_Negative           83
#define OP_And                84
#define OP_Or                 85
#define OP_Not                86
#define OP_Concat             87
#define OP_Noop               88

#define OP_MAX                88

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
*/
Vdbe *sqliteVdbeCreate(Dbbe*);
int sqliteVdbeAddOp(Vdbe*,int,int,int,const char*,int);