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Combine multiple small calls to sqlite3OsWrite into one larger call. (CVS 2910)

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FossilOrigin-Name: e6e6750c24dc8b87be96bdc0e93254d7f0700543
This commit is contained in:
drh
2006-01-10 20:32:32 +00:00
parent fe0f75bb1f
commit 97b5748487
3 changed files with 38 additions and 43 deletions
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67
src/pager.c
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@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.234 2006/01/09 23:40:25 drh Exp $
** @(#) $Id: pager.c,v 1.235 2006/01/10 20:32:32 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -443,16 +443,23 @@ static int read32bits(OsFile *fd, u32 *pRes){
return rc;
}
/*
** Write a 32-bit integer into a string buffer in big-endian byte order.
*/
static void put32bits(char *ac, u32 val){
ac[0] = (val>>24) & 0xff;
ac[1] = (val>>16) & 0xff;
ac[2] = (val>>8) & 0xff;
ac[3] = val & 0xff;
}
/*
** Write a 32-bit integer into the given file descriptor. Return SQLITE_OK
** on success or an error code is something goes wrong.
*/
static int write32bits(OsFile *fd, u32 val){
unsigned char ac[4];
ac[0] = (val>>24) & 0xff;
ac[1] = (val>>16) & 0xff;
ac[2] = (val>>8) & 0xff;
ac[3] = val & 0xff;
put32bits(ac, val);
return sqlite3OsWrite(fd, ac, 4);
}
@@ -463,10 +470,7 @@ static int write32bits(OsFile *fd, u32 val){
static void store32bits(u32 val, PgHdr *p, int offset){
unsigned char *ac;
ac = &((unsigned char*)PGHDR_TO_DATA(p))[offset];
ac[0] = (val>>24) & 0xff;
ac[1] = (val>>16) & 0xff;
ac[2] = (val>>8) & 0xff;
ac[3] = val & 0xff;
put32bits(ac, val);
}
/*
@@ -656,6 +660,7 @@ static int seekJournalHdr(Pager *pPager){
** Followed by (JOURNAL_HDR_SZ - 24) bytes of unused space.
*/
static int writeJournalHdr(Pager *pPager){
char zHeader[sizeof(aJournalMagic)+16];
int rc = seekJournalHdr(pPager);
if( rc ) return rc;
@@ -674,25 +679,17 @@ static int writeJournalHdr(Pager *pPager){
** Actually maybe the whole journal header should be delayed until that
** point. Think about this.
*/
rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
if( rc==SQLITE_OK ){
/* The nRec Field. 0xFFFFFFFF for no-sync journals. */
rc = write32bits(pPager->jfd, pPager->noSync ? 0xffffffff : 0);
}
if( rc==SQLITE_OK ){
/* The random check-hash initialiser */
sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
rc = write32bits(pPager->jfd, pPager->cksumInit);
}
if( rc==SQLITE_OK ){
/* The initial database size */
rc = write32bits(pPager->jfd, pPager->dbSize);
}
if( rc==SQLITE_OK ){
/* The assumed sector size for this process */
rc = write32bits(pPager->jfd, pPager->sectorSize);
}
memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
/* The nRec Field. 0xFFFFFFFF for no-sync journals. */
put32bits(&zHeader[sizeof(aJournalMagic)], pPager->noSync ? 0xffffffff : 0);
/* The random check-hash initialiser */
sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
/* The initial database size */
put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbSize);
/* The assumed sector size for this process */
put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
rc = sqlite3OsWrite(pPager->jfd, zHeader, sizeof(zHeader));
/* The journal header has been written successfully. Seek the journal
** file descriptor to the end of the journal header sector.
@@ -792,7 +789,8 @@ static int writeMasterJournal(Pager *pPager, const char *zMaster){
int rc;
int len;
int i;
u32 cksum = 0;
u32 cksum = 0;
char zBuf[sizeof(aJournalMagic)+2*4];
if( !zMaster || pPager->setMaster) return SQLITE_OK;
pPager->setMaster = 1;
@@ -818,13 +816,10 @@ static int writeMasterJournal(Pager *pPager, const char *zMaster){
rc = sqlite3OsWrite(pPager->jfd, zMaster, len);
if( rc!=SQLITE_OK ) return rc;
rc = write32bits(pPager->jfd, len);
if( rc!=SQLITE_OK ) return rc;
rc = write32bits(pPager->jfd, cksum);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, sizeof(aJournalMagic));
put32bits(zBuf, len);
put32bits(&zBuf[4], cksum);
memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic));
pPager->needSync = !pPager->noSync;
return rc;
}