SQLite

/*
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.40 2001/11/21 02:21:12 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

** 1, not 0.)  Thus a minimum database contains 2 pages.
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include <assert.h>





















/*
** Forward declarations of structures used only in this file.
*/
typedef struct PageOne PageOne;
typedef struct MemPage MemPage;
typedef struct PageHdr PageHdr;
typedef struct Cell Cell;

** cannot be two or more cursors open on the same table is any one of
** cursors is a read/write cursor.  But there can be two or more
** read-only cursors open on the same table.
*/
int sqliteBtreeCursor(Btree *pBt, int iTable, int wrFlag, BtCursor **ppCur){
  int rc;
  BtCursor *pCur;
  ptr nLock;

  if( pBt->page1==0 ){
    rc = lockBtree(pBt);
    if( rc!=SQLITE_OK ){
      *ppCur = 0;
      return rc;
    }

  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }
  rc = initPage(pCur->pPage, pCur->pgnoRoot, 0);
  if( rc!=SQLITE_OK ){
    goto create_cursor_exception;
  }
  nLock = (ptr)sqliteHashFind(&pBt->locks, 0, iTable);
  if( nLock<0 || (nLock>0 && wrFlag) ){
    rc = SQLITE_LOCKED;
    goto create_cursor_exception;
  }
  nLock = wrFlag ? -1 : nLock+1;
  sqliteHashInsert(&pBt->locks, 0, iTable, (void*)nLock);
  pCur->pBt = pBt;

}

/*
** Close a cursor.  The read lock on the database file is released
** when the last cursor is closed.
*/
int sqliteBtreeCloseCursor(BtCursor *pCur){
  ptr nLock;
  Btree *pBt = pCur->pBt;
  if( pCur->pPrev ){
    pCur->pPrev->pNext = pCur->pNext;
  }else{
    pBt->pCursor = pCur->pNext;
  }
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur->pPrev;
  }
  if( pCur->pPage ){
    sqlitepager_unref(pCur->pPage);
  }
  unlockBtreeIfUnused(pBt);
  nLock = (ptr)sqliteHashFind(&pBt->locks, 0, pCur->pgnoRoot);
  assert( nLock!=0 || sqlite_malloc_failed );
  nLock = nLock<0 ? 0 : nLock-1;
  sqliteHashInsert(&pBt->locks, 0, pCur->pgnoRoot, (void*)nLock);
  sqliteFree(pCur);
  return SQLITE_OK;
}

}

/*
** Delete all information from a single table in the database.
*/
int sqliteBtreeClearTable(Btree *pBt, int iTable){
  int rc;
  ptr nLock;
  if( !pBt->inTrans ){
    return SQLITE_ERROR;  /* Must start a transaction first */
  }
  nLock = (ptr)sqliteHashFind(&pBt->locks, 0, iTable);
  if( nLock ){
    return SQLITE_LOCKED;
  }
  rc = clearDatabasePage(pBt, (Pgno)iTable, 0);
  if( rc ){
    sqliteBtreeRollback(pBt);
  }

**     COPY
**     VACUUM
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.56 2001/11/21 02:21:12 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called after a single SQL statement has been
** parsed and we want to execute the VDBE code to implement 

/*
** Set the Expr.token field of the given expression to span all
** text between the two given tokens.
*/
void sqliteExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
  if( pExpr ){
    pExpr->span.z = pLeft->z;
    pExpr->span.n = pRight->n + Addr(pRight->z) - Addr(pLeft->z);
  }
}

/*
** Construct a new expression node for a function with multiple
** arguments.
*/

  int i, j;
  int n;
  char *z, **pz;
  if( (p = pParse->pNewTable)==0 ) return;
  i = p->nCol-1;
  if( i<0 ) return;
  pz = &p->aCol[i].zType;
  n = pLast->n + Addr(pLast->z) - Addr(pFirst->z);
  sqliteSetNString(pz, pFirst->z, n, 0);
  z = *pz;
  if( z==0 ) return;
  for(i=j=0; z[i]; i++){
    int c = z[i];
    if( isspace(c) ) continue;
    z[j++] = c;

  */
  if( !pParse->initFlag ){
    int n, addr;
    Vdbe *v;

    v = sqliteGetVdbe(pParse);
    if( v==0 ) return;
    n = Addr(pEnd->z) - Addr(pParse->sFirstToken.z) + 1;
    if( !p->isTemp ){
      sqliteVdbeAddOp(v, OP_NewRecno, 0, 0);
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeChangeP3(v, -1, "table", P3_STATIC);
      sqliteVdbeAddOp(v, OP_String, 0, 0);
      sqliteVdbeChangeP3(v, -1, p->zName, P3_STATIC);
      sqliteVdbeAddOp(v, OP_String, 0, 0);

        sqliteVdbeAddOp(v, OP_Dup, 0, 0);
        sqliteVdbeAddOp(v, OP_OpenWrite, 1, 0);
      }
    }
    if( !isTemp ){
      addr = sqliteVdbeAddOp(v, OP_String, 0, 0);
      if( pStart && pEnd ){
        n = Addr(pEnd->z) - Addr(pStart->z) + 1;
        sqliteVdbeChangeP3(v, addr, pStart->z, n);
      }
      sqliteVdbeAddOp(v, OP_MakeRecord, 5, 0);
      sqliteVdbeAddOp(v, OP_Put, 0, 0);
    }
    if( pTable ){
      sqliteVdbeAddOp(v, isTemp ? OP_OpenAux : OP_Open, 2, pTab->tnum);

**    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 1.4 2001/11/21 02:21:12 drh Exp $
*/
#include "sqliteInt.h"
#include <assert.h>

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

  return n2 - n1;
}

/*
** Hash and comparison functions when the mode is SQLITE_HASH_POINTER
*/
static int ptrHash(const void *pKey, int nKey){
  uptr x = Addr(pKey);
  return x ^ (x<<8) ^ (x>>8);
}
static int ptrCompare(const void *pKey1, int n1, const void *pKey2, int n2){
  if( pKey1==pKey2 ) return 0;
  if( pKey1<pKey2 ) return -1;
  return 1;
}

/*
** Hash and comparison functions when the mode is SQLITE_HASH_STRING
*/
static int strHash(const void *pKey, int nKey){
  return sqliteHashNoCase((const char*)pKey, nKey); 

/*
** 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 1.70 2001/11/21 02:21:12 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables.
*/
#define MAX_PAGES   100
#define TEMP_PAGES   25

/*
** Integers of known sizes.  These typedefs might change for architectures
** where the sizes very.  Preprocessor macros are available so that the
** types can be conveniently redefined at compile-type.  Like this:
**
**         cc '-DUINTPTR_TYPE=long long int' ...
*/
#ifndef UINT32_TYPE
# define UINT32_TYPE unsigned int
#endif
#ifndef UINT16_TYPE
# define UINT16_TYPE unsigned short int
#endif
#ifndef UINT8_TYPE
# define UINT8_TYPE unsigned char
#endif
#ifndef INTPTR_TYPE
# define INTPTR_TYPE int
#endif
typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
typedef INTPTR_TYPE ptr;           /* Big enough to hold a pointer */
typedef unsigned INTPTR_TYPE uptr; /* Big enough to hold a pointer */

/*
** This macro casts a pointer to an integer.  Useful for doing
** pointer arithmetic.
*/
#define Addr(X)  ((uptr)X)

/*
** The maximum number of bytes of data that can be put into a single
** row of a single table.  The upper bound on this limit is 16777215
** bytes (or 16MB-1).  We have arbitrarily set the limit to just 1MB
** here because the overflow page chain is inefficient for really big
** records and we want to discourage people from thinking that 

**    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 UPDATE statements.
**
** $Id: update.c,v 1.22 2001/11/21 02:21:12 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process an UPDATE statement.
*/
void sqliteUpdate(

      sqliteSetString(&pParse->zErrMsg, "no such column: ", 
         pChanges->a[i].zName, 0);
      pParse->nErr++;
      goto update_cleanup;
    }
  }

  /* Allocate memory for the array apIdx[] and fill it with pointers to every
  ** index that needs to be updated.  Indices only need updating if their
  ** key includes one of the columns named in pChanges.
  */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    for(i=0; i<pIdx->nColumn; i++){
      if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
    }

    for(j=0; j<pIdx->nColumn; j++){
      sqliteVdbeAddOp(v, OP_Column, base, pIdx->aiColumn[j]);
    }
    sqliteVdbeAddOp(v, OP_MakeIdxKey, pIdx->nColumn, 0);
    sqliteVdbeAddOp(v, OP_IdxDelete, base+i+1, 0);
  }

  /* Compute new data for this record.  
  */
  for(i=0; i<pTab->nCol; i++){
    j = aXRef[i];
    if( j<0 ){
      sqliteVdbeAddOp(v, OP_Column, base, i);
    }else{
      sqliteExprCode(pParse, pChanges->a[j].pExpr);

**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
** $Id: util.c,v 1.32 2001/11/21 02:21:12 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

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

#define _64e63 (_64e15 * _64e16 * _64e16 * _64e16)
#define _64e64 (_64e16 * _64e16 * _64e16 * _64e16)

/*
** The following procedure converts a double-precision floating point
** number into a string.  The resulting string has the property that
** two such strings comparied using strcmp() or memcmp() will give the
** same results as a numeric comparison of the original floating point
** numbers.
**
** This routine is used to generate database keys from floating point
** numbers such that the keys sort in the same order as the original
** floating point numbers even though the keys are compared using
** memcmp().
**
** The calling function should have allocated at least 14 characters

}


proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}

chng {2001 Nov ?? (2.1.2)} {
<li>Changes to support 64-bit architectures.</li>
}

chng {2001 Nov 13 (2.1.1)} {
<li>Bug fix: Sometimes arbirary strings were passed to the callback
    function when the actual value of a column was NULL.</li>
}

chng {2001 Nov 12 (2.1.0)} {

#
# Run this Tcl script to generate the vdbe.html file.
#
set rcsid {$Id: vdbe.tcl,v 1.8 2001/11/21 02:21:13 drh Exp $}

puts {<html>
<head>
  <title>The Virtual Database Engine of SQLite</title>
</head>
<body bgcolor=white>
<h1 align=center>

code using a script so you can also get information about the
various opcodes directly from the <b>vdbe.c</b> source file.
If you have successfully read this far, you should have little
difficulty understanding the rest.</p>

<p>If you find errors in either the documentation or the code,
feel free to fix them and/or contact the author at
<a href="mailto:drh@hwaci.com">drh@hwaci.com</a>.  Your bug fixes or
suggestions are always welcomed.</p>
}

puts {
<p><hr /></p>
<p><a href="index.html"><img src="/goback.jpg" border=0 />
Back to the SQLite Home Page</a>
</p>

</body></html>}