From: drh <drh@noemail.net>
Date: Tue, 10 Jan 2006 20:32:32 +0000 (+0000)
Subject: Combine multiple small calls to sqlite3OsWrite into one larger call. (CVS 2910)
X-Git-Tag: version-3.6.10~3257
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97b574848714faed837372c67274e4654d176da0;p=thirdparty%2Fsqlite.git

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

FossilOrigin-Name: e6e6750c24dc8b87be96bdc0e93254d7f0700543
---

diff --git a/manifest b/manifest
index 06e726519e..b4153d014d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improved\scomments\son\sthe\sserver\sand\sasynchronous\sI/O\sdemo\sprograms.\s(CVS\s2909)
-D 2006-01-10T20:01:19
+C Combine\smultiple\ssmall\scalls\sto\ssqlite3OsWrite\sinto\sone\slarger\scall.\s(CVS\s2910)
+D 2006-01-10T20:32:32
 F Makefile.in ab3ffd8d469cef4477257169b82810030a6bb967
 F Makefile.linux-gcc aee18d8a05546dcf1888bd4547e442008a49a092
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -59,7 +59,7 @@ F src/os_unix.c 8943febbedc79649d21ec1ed14de14ad8214c899
 F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
 F src/os_win.c 8ef250a0965a55dbcd8ef785e03f9f3292e6ade2
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c f84488fa616f1279761aaf06b0acc42af345d3a5
+F src/pager.c 0a59a320b0da6b22d2dd4411d16e300ff1b947c8
 F src/pager.h e0acb095b3ad0bca48f2ab00c87346665643f64f
 F src/parse.y 83df51fea35f68f7e07384d75dce83d1ed30434c
 F src/pragma.c 711992e440ce78569322dd625d2cfe1cd696ccfb
@@ -340,7 +340,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl a99cf5f6d8bd4d5537584a2b342f0fb9fa601d8b
 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
-P 1cf6855430352ffbf921a977186345d7272fe272
-R c77d71bb3bbb59cc1b67cf59dbab5a91
+P c0f47ccbc915f20d56f393383c21b4026785e6a5
+R 47f576a3900e4c28937875b78f472e44
 U drh
-Z 85b6b185878e0427b46314ea83850303
+Z b4dc310261f3df513fff82ddf0ae5002
diff --git a/manifest.uuid b/manifest.uuid
index b1df334272..55db504846 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c0f47ccbc915f20d56f393383c21b4026785e6a5
\ No newline at end of file
+e6e6750c24dc8b87be96bdc0e93254d7f0700543
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 08582ef01f..a8d601e526 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -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"
@@ -444,15 +444,22 @@ static int read32bits(OsFile *fd, u32 *pRes){
 }
 
 /*
-** Write a 32-bit integer into the given file descriptor.  Return SQLITE_OK
-** on success or an error code is something goes wrong.
+** Write a 32-bit integer into a string buffer in big-endian byte order.
 */
-static int write32bits(OsFile *fd, u32 val){
-  unsigned char ac[4];
+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];
+  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;
 }