/*
** 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.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem. The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.1.1.1 2004/08/08 15:03:57 matt Exp $
*/
/*
** The size of one page
**
** You can change this value to another (reasonable) value you want.
** It need not be a power of two, though the interface to the disk
** will likely be faster if it is.
**
** Experiments show that a page size of 1024 gives the best speed
** for common usages. The speed differences for different sizes
** such as 512, 2048, 4096, an so forth, is minimal. Note, however,
** that changing the page size results in a completely imcompatible
** file format.
*/
#ifndef SQLITE_PAGE_SIZE
#define SQLITE_PAGE_SIZE 1024
#endif
/*
** Number of extra bytes of data allocated at the end of each page and
** stored on disk but not used by the higher level btree layer. Changing
** this value results in a completely incompatible file format.
*/
#ifndef SQLITE_PAGE_RESERVE
#define SQLITE_PAGE_RESERVE 0
#endif
/*
** The total number of usable bytes stored on disk for each page.
** The usable bytes come at the beginning of the page and the reserve
** bytes come at the end.
*/
#define SQLITE_USABLE_SIZE (SQLITE_PAGE_SIZE-SQLITE_PAGE_RESERVE)
/*
** Maximum number of pages in one database. (This is a limitation of
** imposed by 4GB files size limits.)
*/
#define SQLITE_MAX_PAGE 1073741823
/*
** The type used to represent a page number. The first page in a file
** is called page 1. 0 is used to represent "not a page".
*/
typedef
unsigned
int
Pgno;
/*
** Each open file is managed by a separate instance of the "Pager" structure.
*/
typedef
struct
Pager Pager;
/*
** See source code comments for a detailed description of the following
** routines:
*/
int
sqlitepager_open(Pager **ppPager,
const
char
*zFilename,
int
nPage,
int
nExtra,
int
useJournal);
void
sqlitepager_set_destructor(Pager*,
void
(*)(
void
*));
void
sqlitepager_set_cachesize(Pager*,
int
);
int
sqlitepager_close(Pager *pPager);
int
sqlitepager_get(Pager *pPager, Pgno pgno,
void
**ppPage);
void
*sqlitepager_lookup(Pager *pPager, Pgno pgno);
int
sqlitepager_ref(
void
*);
int
sqlitepager_unref(
void
*);
Pgno sqlitepager_pagenumber(
void
*);
int
sqlitepager_write(
void
*);
int
sqlitepager_iswriteable(
void
*);
int
sqlitepager_overwrite(Pager *pPager, Pgno pgno,
void
*);
int
sqlitepager_pagecount(Pager*);
int
sqlitepager_truncate(Pager*,Pgno);
int
sqlitepager_begin(
void
*);
int
sqlitepager_commit(Pager*);
int
sqlitepager_rollback(Pager*);
int
sqlitepager_isreadonly(Pager*);
int
sqlitepager_ckpt_begin(Pager*);
int
sqlitepager_ckpt_commit(Pager*);
int
sqlitepager_ckpt_rollback(Pager*);
void
sqlitepager_dont_rollback(
void
*);
void
sqlitepager_dont_write(Pager*, Pgno);
int
*sqlitepager_stats(Pager*);
void
sqlitepager_set_safety_level(Pager*,
int
);
const
char
*sqlitepager_filename(Pager*);
int
sqlitepager_rename(Pager*,
const
char
*zNewName);
void
sqlitepager_set_codec(Pager*,
void
(*)(
void
*,
void
*,Pgno,
int
),
void
*);
#ifdef SQLITE_TEST
void
sqlitepager_refdump(Pager*);
int
pager_refinfo_enable;
int
journal_format;
#endif