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php5  5.3.10
pager.h
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00001 /*
00002 ** 2001 September 15
00003 **
00004 ** The author disclaims copyright to this source code.  In place of
00005 ** a legal notice, here is a blessing:
00006 **
00007 **    May you do good and not evil.
00008 **    May you find forgiveness for yourself and forgive others.
00009 **    May you share freely, never taking more than you give.
00010 **
00011 *************************************************************************
00012 ** This header file defines the interface that the sqlite page cache
00013 ** subsystem.  The page cache subsystem reads and writes a file a page
00014 ** at a time and provides a journal for rollback.
00015 **
00016 ** @(#) $Id: pager.h 195361 2005-09-07 15:11:33Z iliaa $
00017 */
00018 
00019 /*
00020 ** The size of one page
00021 **
00022 ** You can change this value to another (reasonable) value you want.
00023 ** It need not be a power of two, though the interface to the disk
00024 ** will likely be faster if it is.
00025 **
00026 ** Experiments show that a page size of 1024 gives the best speed
00027 ** for common usages.  The speed differences for different sizes
00028 ** such as 512, 2048, 4096, an so forth, is minimal.  Note, however,
00029 ** that changing the page size results in a completely imcompatible
00030 ** file format.
00031 */
00032 #ifndef SQLITE_PAGE_SIZE
00033 #define SQLITE_PAGE_SIZE 1024
00034 #endif
00035 
00036 /*
00037 ** Number of extra bytes of data allocated at the end of each page and
00038 ** stored on disk but not used by the higher level btree layer.  Changing
00039 ** this value results in a completely incompatible file format.
00040 */
00041 #ifndef SQLITE_PAGE_RESERVE
00042 #define SQLITE_PAGE_RESERVE 0
00043 #endif
00044 
00045 /*
00046 ** The total number of usable bytes stored on disk for each page.
00047 ** The usable bytes come at the beginning of the page and the reserve
00048 ** bytes come at the end.
00049 */
00050 #define SQLITE_USABLE_SIZE (SQLITE_PAGE_SIZE-SQLITE_PAGE_RESERVE)
00051 
00052 /*
00053 ** Maximum number of pages in one database.  (This is a limitation of
00054 ** imposed by 4GB files size limits.)
00055 */
00056 #define SQLITE_MAX_PAGE 1073741823
00057 
00058 /*
00059 ** The type used to represent a page number.  The first page in a file
00060 ** is called page 1.  0 is used to represent "not a page".
00061 */
00062 typedef unsigned int Pgno;
00063 
00064 /*
00065 ** Each open file is managed by a separate instance of the "Pager" structure.
00066 */
00067 typedef struct Pager Pager;
00068 
00069 /*
00070 ** See source code comments for a detailed description of the following
00071 ** routines:
00072 */
00073 int sqlitepager_open(Pager **ppPager, const char *zFilename,
00074                      int nPage, int nExtra, int useJournal);
00075 void sqlitepager_set_destructor(Pager*, void(*)(void*));
00076 void sqlitepager_set_cachesize(Pager*, int);
00077 int sqlitepager_close(Pager *pPager);
00078 int sqlitepager_get(Pager *pPager, Pgno pgno, void **ppPage);
00079 void *sqlitepager_lookup(Pager *pPager, Pgno pgno);
00080 int sqlitepager_ref(void*);
00081 int sqlitepager_unref(void*);
00082 Pgno sqlitepager_pagenumber(void*);
00083 int sqlitepager_write(void*);
00084 int sqlitepager_iswriteable(void*);
00085 int sqlitepager_overwrite(Pager *pPager, Pgno pgno, void*);
00086 int sqlitepager_pagecount(Pager*);
00087 int sqlitepager_truncate(Pager*,Pgno);
00088 int sqlitepager_begin(void*);
00089 int sqlitepager_commit(Pager*);
00090 int sqlitepager_rollback(Pager*);
00091 int sqlitepager_isreadonly(Pager*);
00092 int sqlitepager_ckpt_begin(Pager*);
00093 int sqlitepager_ckpt_commit(Pager*);
00094 int sqlitepager_ckpt_rollback(Pager*);
00095 void sqlitepager_dont_rollback(void*);
00096 void sqlitepager_dont_write(Pager*, Pgno);
00097 int *sqlitepager_stats(Pager*);
00098 void sqlitepager_set_safety_level(Pager*,int);
00099 const char *sqlitepager_filename(Pager*);
00100 int sqlitepager_rename(Pager*, const char *zNewName);
00101 void sqlitepager_set_codec(Pager*,void(*)(void*,void*,Pgno,int),void*);
00102 
00103 #ifdef SQLITE_TEST
00104 void sqlitepager_refdump(Pager*);
00105 int pager_refinfo_enable;
00106 int journal_format;
00107 #endif