SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the implementation of generic hash-tables
** used in SQLite.
**
** $Id: hash.c,v 1.6 2002/01/14 09:28:20 drh Exp $
*/
#include "sqliteInt.h"
#include <assert.h>

/* Turn bulk memory into a hash table object by initializing the
** fields of the Hash structure.
**

** single parameter "keyClass".  The return value of hashFunction()
** is a pointer to another function.  Specifically, the return value
** of hashFunction() is a pointer to a function that takes two parameters
** with types "const void*" and "int" and returns an "int".
*/
static int (*hashFunction(int keyClass))(const void*,int){
  switch( keyClass ){
    case SQLITE_HASH_INT:     return &intHash;
    case SQLITE_HASH_POINTER: return &ptrHash;
    case SQLITE_HASH_STRING:  return &strHash;
    case SQLITE_HASH_BINARY:  return &binHash;;
    default: break;
  }
  return 0;
}

/*
** Return a pointer to the appropriate hash function given the key class.
**
** For help in interpreted the obscure C code in the function definition,
** see the header comment on the previous function.
*/
static int (*compareFunction(int keyClass))(const void*,int,const void*,int){
  switch( keyClass ){
    case SQLITE_HASH_INT:     return &intCompare;
    case SQLITE_HASH_POINTER: return &ptrCompare;
    case SQLITE_HASH_STRING:  return &strCompare;
    case SQLITE_HASH_BINARY:  return &binCompare;
    default: break;
  }
  return 0;
}


/* Resize the hash table so that it cantains "new_size" buckets.

  wrote = write(id->fd, pBuf, amt);
  if( wrote<amt ) return SQLITE_FULL;
  return SQLITE_OK;
#endif
#if OS_WIN
  DWORD wrote;
  SimulateIOError(SQLITE_IOERR);
  if( !WriteFile(id->h, pBuf, amt, &wrote, 0) || (int)wrote<amt ){
    return SQLITE_FULL;
  }
  return SQLITE_OK;
#endif
}

/*

**
** This header file (together with is companion C source-code file
** "os.c") attempt to abstract the underlying operating system so that
** the SQLite library will work on both POSIX and windows systems.
*/
#ifndef _SQLITE_OS_H_
#define _SQLITE_OS_H_

#ifdef WIN32
#  define OS_WIN 1
#  undef  OS_UNIX
#else
#  define OS_UNIX 1
#  undef  OS_WIN
#endif

/*
** A handle for an open file is stored in an OsFile object.
*/
#if OS_UNIX
  typedef struct OsFile OsFile;
  struct OsFile {

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.36 2002/01/14 09:28:20 drh Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "os.h"
#include <assert.h>
#include <string.h>

        assert( pPager->aHash[h]==pPg );
        pPager->aHash[h] = pPg->pNextHash;
      }
      pPg->pNextHash = pPg->pPrevHash = 0;
      pPager->nOvfl++;
    }
    pPg->pgno = pgno;
    if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
      pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
    }else{
      pPg->inJournal = 0;
    }
    pPg->dirty = 0;
    pPg->nRef = 1;
    REFINFO(pPg);
    pPager->nRef++;
    h = pager_hash(pgno);
    pPg->pNextHash = pPager->aHash[h];
    pPager->aHash[h] = pPg;
    if( pPg->pNextHash ){
      assert( pPg->pNextHash->pPrevHash==0 );
      pPg->pNextHash->pPrevHash = pPg;
    }
    if( pPager->dbSize<0 ) sqlitepager_pagecount(pPager);
    if( pPager->dbSize<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, SQLITE_PAGE_SIZE);
    }else{
      int rc;
      sqliteOsSeek(&pPager->fd, (pgno-1)*SQLITE_PAGE_SIZE);
      rc = sqliteOsRead(&pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
      if( rc!=SQLITE_OK ){
        return rc;

  }
  assert( pPager->state==SQLITE_WRITELOCK );
  assert( pPager->journalOpen );

  /* The journal now exists and we have a write lock on the
  ** main database file.  Write the current page to the journal.
  */
  if( (int)pPg->pgno <= pPager->origDbSize ){
    rc = sqliteOsWrite(&pPager->jfd, &pPg->pgno, sizeof(Pgno));
    if( rc==SQLITE_OK ){
      rc = sqliteOsWrite(&pPager->jfd, pData, SQLITE_PAGE_SIZE);
    }
    if( rc!=SQLITE_OK ){
      sqlitepager_rollback(pPager);
      pPager->errMask |= PAGER_ERR_FULL;
      return rc;
    }
    assert( pPager->aInJournal!=0 );
    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
    pPager->needSync = 1;
  }

  /* Mark the current page as being in the journal and return.
  */
  pPg->inJournal = 1;
  if( pPager->dbSize<(int)pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}

/*
** Return TRUE if the page given in the argument was previously passed

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.35 2002/01/14 09:28:20 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** If malloc() ever fails, this global variable gets set to 1.

    return;
  }
  *z++ = zDigit[(exp>>6)&0x3f];
  *z++ = zDigit[exp & 0x3f];
  while( r>0.0 && cnt<10 ){
    int digit;
    r *= 64.0;
    digit = (int)r;
    assert( digit>=0 && digit<64 );
    *z++ = zDigit[digit & 0x3f];
    r -= digit;
    cnt++;
  }
  *z = 0;
}

** 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 1.106 2002/01/14 09:28:20 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

** Any prior string or real representation is invalidated.  
** NULLs are converted into 0.
*/
#define Integerify(P,I) \
    if(((P)->aStack[(I)].flags&STK_Int)==0){ hardIntegerify(P,I); }
static void hardIntegerify(Vdbe *p, int i){
  if( p->aStack[i].flags & STK_Real ){
    p->aStack[i].i = (int)p->aStack[i].r;
    Release(p, i);
  }else if( p->aStack[i].flags & STK_Str ){
    p->aStack[i].i = atoi(p->zStack[i]);
    Release(p, i);
  }else{
    p->aStack[i].i = 0;
  }

      case OP_Multiply:    b *= a;       break;
      case OP_Divide: {
        if( a==0.0 ) goto divide_by_zero;
        b /= a;
        break;
      }
      default: {
        int ia = (int)a;
        int ib = (int)b;
        if( ia==0.0 ) goto divide_by_zero;
        b = ib % ia;
        break;
      }
    }
    POPSTACK;
    Release(p, nos);

  if( pFocus==0 ) goto no_mem;
  if( i>=0 && i<p->agg.nMem ){
    Mem *pMem = &pFocus->aMem[i];
    if( pMem->s.flags!=STK_Int ){
      if( pMem->s.flags & STK_Int ){
        /* Do nothing */
      }else if( pMem->s.flags & STK_Real ){
        pMem->s.i = (int)pMem->s.r;
      }else if( pMem->s.flags & STK_Str ){
        pMem->s.i = atoi(pMem->z);
      }else{
        pMem->s.i = 0;
      }
      if( pMem->s.flags & STK_Dyn ) sqliteFree(pMem->z);
      pMem->z = 0;

  sprintf(zBuf,"%d",pc);
  sqliteSetString(pzErrMsg, "too few operands on stack at ", zBuf, 0);
  rc = SQLITE_INTERNAL;
  goto cleanup;

  /* Jump here if an illegal or illformed instruction is executed.
  */
VERIFY(
bad_instruction:
  sprintf(zBuf,"%d",pc);
  sqliteSetString(pzErrMsg, "illegal operation at ", zBuf, 0);
  rc = SQLITE_INTERNAL;
  goto cleanup;
)
}