SQLite

** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.50 2001/09/15 14:43:39 drh Exp $
*/
#include "sqlite.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>
#include <stdlib.h>

** Integers of known sizes.  These typedefs much change for architectures
** where the sizes very.
*/
typedef unsigned int u32;             /* 4-byte unsigned integer */
typedef unsigned short int u16;       /* 2-byte unsigned integer */
typedef unsigned char u8;             /* 1-byte unsigned integer */

/*
** The maximum number of bytes of data that can be put into a single
** row of a single table.
*/
#define MAX_BYTES_PER_ROW  65535

/*
** If memory allocation problems are found, recompile with
**
**      -DMEMORY_DEBUG=1
**
** to enable some sanity checking on malloc() and free().  To
** check for memory leaks, recompile with

** 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 1.69 2001/09/15 14:43:39 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include <unistd.h>

/*
** SQL is translated into a sequence of instructions to be

  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( (aStack[i].flags & STK_Null)==0 ){
      if( Stringify(p, i) ) goto no_mem;
      nByte += aStack[i].n;
    }
  }
  nByte += sizeof(addr)*nField;
  if( nByte>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  zNewRecord = sqliteMalloc( nByte );
  if( zNewRecord==0 ) goto no_mem;
  j = 0;
  addr = sizeof(addr)*nField;

  break;
}

/* Opcode: MakeKey P1 P2 *
**
** Convert the top P1 entries of the stack into a single entry suitable
** for use as the key in an index or a sort.  The top P1 records are
** converted to strings and merged.  The null-terminator on each string
** is retained and used as a separator.  The entire string is also
** null-terminated.
** The lowest entry in the stack is the first field and the top of the
** stack becomes the last.
**
** If P2 is not zero, then the original entries remain on the stack
** and the new key is pushed on top.  If P2 is zero, the original
** data is popped off the stack first then the new key is pushed
** back in its place.
**

  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      nByte++;
    }else{
      if( Stringify(p, i) ) goto no_mem;
      nByte += aStack[i].n;
    }
  }
  if( nByte+sizeof(u32)>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  zNewKey = sqliteMalloc( nByte );
  if( zNewKey==0 ) goto no_mem;
  j = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zNewKey[j++] = 0;
    }else{
      memcpy(&zNewKey[j], zStack[i], aStack[i].n);
      j += aStack[i].n;
    }

  }

  if( pOp->p2==0 ) PopStack(p, nField);
  VERIFY( NeedStack(p, p->tos+1); )
  p->tos++;
  aStack[p->tos].n = nByte;
  aStack[p->tos].flags = STK_Str|STK_Dyn;
  zStack[p->tos] = zNewKey;
  break;
}

/* Opcode: MakeIdxKey P1 * *
**
** Convert the top P1 entries of the stack into a single entry suitable
** for use as the key in an index.  In addition, take one additional integer
** off of the stack, treat that integer as a four-byte record number, and
** append the four bytes to the key.  Thus a total of P1+1 entries are
** popped from the stack for this instruction and a single entry is pushed
** back.  The first P1 entries that are popped are strings and the last
** entry (the lowest on the stack) is an integer record number.
**
** The converstion of the first P1 string entries occurs just like in
** MakeKey.  Each entry is separated from the others by a null.
** The entire concatenation is null-terminated.  The lowest entry
** in the stack is the first field and the top of the stack becomes the
** last.
**
** See also:  MakeKey, SortMakeKey
*/
case OP_MakeIdxKey: {

  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      nByte++;
    }else{
      if( Stringify(p, i) ) goto no_mem;
      nByte += aStack[i].n;
    }
  }
  if( nByte>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  zNewKey = sqliteMalloc( nByte );
  if( zNewKey==0 ) goto no_mem;
  j = 0;
  for(i=p->tos-nField+1; i<=p->tos; i++){
    if( aStack[i].flags & STK_Null ){
      zNewKey[j++] = 0;
    }else{
      memcpy(&zNewKey[j], zStack[i], aStack[i].n);
      j += aStack[i].n;
    }

  }

  Integerify(p, p->tos-nField);
  memcpy(&zNewKey[j], &aStack[p->tos-nField].i, sizeof(u32));
  PopStack(p, nField+1);
  VERIFY( NeedStack(p, p->tos+1); )
  p->tos++;
  aStack[p->tos].n = nByte;
  aStack[p->tos].flags = STK_Str|STK_Dyn;

** record numbers onto the stack until all records with the same key
** have been returned.
**
** Note that the key for this opcode should be built using MakeKey
** but the key used for PutIdx and DeleteIdx should be built using
** MakeIdxKey.  The difference is that MakeIdxKey adds a 4-bytes
** record number to the end of the key in order to specify a particular
** entry in the index.  MakeKey omits the 4-byte record number.
** The search that this BeginIdx instruction initiates will span all
** entries in the index where the MakeKey generated key matches all
** but the last four bytes of the MakeIdxKey generated key.
*/
case OP_BeginIdx: {
  int i = pOp->p1;
  int tos = p->tos;
  int res, rx;
  Cursor *pCrsr;
  VERIFY( if( tos<0 ) goto not_enough_stack; )
  if( i>=0 && i<p->nCursor && (pCrsr = &p->aCsr[i])->pCursor!=0 ){
    if( Stringify(p, tos) ) goto no_mem;
    if( pCrsr->zKey ) sqliteFree(pCrsr->zKey);
    pCrsr->nKey = aStack[tos].n;
    pCrsr->zKey = sqliteMalloc( 2*pCrsr->nKey );
    if( pCrsr->zKey==0 ) goto no_mem;
    pCrsr->zBuf = &pCrsr->zKey[pCrsr->nKey];
    memcpy(pCrsr->zKey, zStack[tos], aStack[tos].n);
    pCrsr->zKey[aStack[tos].n] = 0;
    rx = sqliteBtreeMoveto(pCrsr->pCursor, zStack[tos], aStack[tos].n, &res);
    pCrsr->atFirst = rx==SQLITE_OK && res>0;
    pCrsr->recnoIsValid = 0;
  }
  POPSTACK;
  break;
}

/* Opcode: NextIdx P1 P2 *
**
** The P1 cursor points to an SQL index for which a BeginIdx operation
** has been issued.  This operation retrieves the next record from that
** cursor and verifies that the key on the record matches the key that
** was pulled from the stack by the BeginIdx instruction.  If they do
** match, then the last 4 bytes of the key on the record hold a record
** number and that record number is extracted and pushed on the stack.

** If the keys do not match, there is an immediate jump to instruction P2.
*/
case OP_NextIdx: {
  int i = pOp->p1;
  int tos = ++p->tos;
  Cursor *pCrsr;
  BtCursor *pCur;
  int rx, res, size;

    }else{
      rx = sqliteBtreeNext(pCur, &res);
      if( rx!=SQLITE_OK ) goto abort_due_to_error;
    }
    sqliteBtreeKeySize(pCur, &size);
    if( res>0 || size!=pCrsr->nKey+sizeof(u32) ||
      sqliteBtreeKey(pCur, 0, pCrsr->nKey, pCrsr->zBuf)!=pCrsr->nKey ||
      memcmp(pCrsr->zKey, pCrsr->zBuf, pCrsr->nKey)!=0
    ){
      pc = pOp->p2 - 1;
      POPSTACK;
    }else{
      int recno;
      sqliteBtreeKey(pCur, pCrsr->nKey, sizeof(u32), (char*)&recno);
      p->aCsr[i].lastRecno = aStack[tos].i = recno;

        }else if( aStack[i].flags & STK_Real ){
          fprintf(p->trace, " r:%g", aStack[i].r);
        }else if( aStack[i].flags & STK_Str ){
          int j, k;
          char zBuf[100];
          zBuf[0] = ' ';
          zBuf[1] = (aStack[i].flags & STK_Dyn)!=0 ? 'z' : 's';
          zBuf[2] = '[';
          k = 3;
          for(j=0; j<20 && j<aStack[i].n; j++){
            int c = zStack[i][j];
            if( c==0 && j==aStack[i].n-1 ) break;
            if( isprint(c) && !isspace(c) ){
              zBuf[k++] = c;
            }else{
              zBuf[k++] = '.';
            }
          }
          zBuf[k++] = ']';
          zBuf[k++] = 0;
          fprintf(p->trace, "%s", zBuf);
        }else{
          fprintf(p->trace, " ???");
        }
      }
      fprintf(p->trace,"\n");