From: drh <drh@noemail.net>
Date: Wed, 23 Aug 2017 14:45:59 +0000 (+0000)
Subject: Smaller and faster implementation of the fillInCell() routine.
X-Git-Tag: version-3.21.0~133
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5e27e1dc499097272615b0591c457b7967aedf24;p=thirdparty%2Fsqlite.git

Smaller and faster implementation of the fillInCell() routine.

FossilOrigin-Name: 77074990edef6c42bdfe7ccce1affc8ed64a86dde3ad4fa50b60ba0a6d851eea
---

diff --git a/manifest b/manifest
index 55217ab212..79af87c73a 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Update\sdocumentation\sto\smake\sit\sclear\sthat\sSQLITE_SOURCE_ID\sand\nsqlite3_sourceid()\smight\schanges\sif\sthe\ssource\scode\sis\sedited.
-D 2017-08-22T21:23:02.258
+C Smaller\sand\sfaster\simplementation\sof\sthe\sfillInCell()\sroutine.
+D 2017-08-23T14:45:59.667
 F Makefile.in c644bbe8ebe4aae82ad6783eae6b6beea4c727b99ff97568b847ced5e2ac7afb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 25b154da7f0b3d4924f27378c1f8d006285b80811f1ccf3ed953dbebf6282136
@@ -399,7 +399,7 @@ F src/auth.c 6277d63837357549fe14e723490d6dc1a38768d71c795c5eb5c0f8a99f918f73
 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
 F src/btmutex.c 0e9ce2d56159b89b9bc8e197e023ee11e39ff8ca
-F src/btree.c e1a98bef27d6189df5c5b8b3c9b5e53d6b74bf9a936af97757c21e9ea6a5c6b2
+F src/btree.c ea10ca63430533c358da32e5d2b8b22aa3c6a9e84f295139e4e5bb00f635726d
 F src/btree.h 32ef5d3f25dc70ef1ee9cecf84a023c21378f06a57cd701d2e866e141b150f09
 F src/btreeInt.h 55b702efce17e5d1941865464227d3802cfc9c7c832fac81d4c94dced47a71fc
 F src/build.c b47a0320c6d237718b8f493ac97d37d1071bce12aca668b15219187150c41295
@@ -1650,7 +1650,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 564c7340a3368501c3da885afde52123ed7f558801f6190cbe6173dfe9704b70
-R b1a5f4a03931a03b3cf49a93760947b3
+P e69c0c8770d3cc2fcdc779c6290caf1575644d457326caa00327b9070251d620
+R 66591a7ad128e50f7a0c04de7cb52832
 U drh
-Z 80eecc829d5290754bef086590571027
+Z 50b9a412665b926c36fcdf17b0a625f8
diff --git a/manifest.uuid b/manifest.uuid
index 0e97d0f48f..0e5f5791b5 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-e69c0c8770d3cc2fcdc779c6290caf1575644d457326caa00327b9070251d620
\ No newline at end of file
+77074990edef6c42bdfe7ccce1affc8ed64a86dde3ad4fa50b60ba0a6d851eea
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index ecdbb6d0a3..b6e5fbc508 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -6218,21 +6218,20 @@ static int fillInCell(
 ){
   int nPayload;
   const u8 *pSrc;
-  int nSrc, n, rc;
+  int nSrc, n, rc, mn;
   int spaceLeft;
-  MemPage *pOvfl = 0;
-  MemPage *pToRelease = 0;
+  MemPage *pToRelease;
   unsigned char *pPrior;
   unsigned char *pPayload;
-  BtShared *pBt = pPage->pBt;
-  Pgno pgnoOvfl = 0;
+  BtShared *pBt;
+  Pgno pgnoOvfl;
   int nHeader;
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
 
   /* pPage is not necessarily writeable since pCell might be auxiliary
   ** buffer space that is separate from the pPage buffer area */
-  assert( pCell<pPage->aData || pCell>=&pPage->aData[pBt->pageSize]
+  assert( pCell<pPage->aData || pCell>=&pPage->aData[pPage->pBt->pageSize]
             || sqlite3PagerIswriteable(pPage->pDbPage) );
 
   /* Fill in the header. */
@@ -6252,25 +6251,36 @@ static int fillInCell(
   }
   
   /* Fill in the payload */
+  pPayload = &pCell[nHeader];
   if( nPayload<=pPage->maxLocal ){
+    /* This is the common case where everything fits on the btree page
+    ** and no overflow pages are required. */
     n = nHeader + nPayload;
     testcase( n==3 );
     testcase( n==4 );
     if( n<4 ) n = 4;
     *pnSize = n;
-    spaceLeft = nPayload;
-    pPrior = pCell;
-  }else{
-    int mn = pPage->minLocal;
-    n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
-    testcase( n==pPage->maxLocal );
-    testcase( n==pPage->maxLocal+1 );
-    if( n > pPage->maxLocal ) n = mn;
-    spaceLeft = n;
-    *pnSize = n + nHeader + 4;
-    pPrior = &pCell[nHeader+n];
+    assert( nSrc<=nPayload );
+    testcase( nSrc<nPayload );
+    memcpy(pPayload, pSrc, nSrc);
+    memset(pPayload+nSrc, 0, nPayload-nSrc);
+    return SQLITE_OK;
   }
-  pPayload = &pCell[nHeader];
+
+  /* If we reach this point, it means that some of the content will need
+  ** to spill onto overflow pages.
+  */
+  mn = pPage->minLocal;
+  n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
+  testcase( n==pPage->maxLocal );
+  testcase( n==pPage->maxLocal+1 );
+  if( n > pPage->maxLocal ) n = mn;
+  spaceLeft = n;
+  *pnSize = n + nHeader + 4;
+  pPrior = &pCell[nHeader+n];
+  pToRelease = 0;
+  pgnoOvfl = 0;
+  pBt = pPage->pBt;
 
   /* At this point variables should be set as follows:
   **
@@ -6296,8 +6306,35 @@ static int fillInCell(
 #endif
 
   /* Write the payload into the local Cell and any extra into overflow pages */
-  while( nPayload>0 ){
+  while( 1 ){
+    n = nPayload;
+    if( n>spaceLeft ) n = spaceLeft;
+
+    /* If pToRelease is not zero than pPayload points into the data area
+    ** of pToRelease.  Make sure pToRelease is still writeable. */
+    assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
+
+    /* If pPayload is part of the data area of pPage, then make sure pPage
+    ** is still writeable */
+    assert( pPayload<pPage->aData || pPayload>=&pPage->aData[pBt->pageSize]
+            || sqlite3PagerIswriteable(pPage->pDbPage) );
+
+    if( nSrc>=n ){
+      memcpy(pPayload, pSrc, n);
+    }else if( nSrc>0 ){
+      n = nSrc;
+      memcpy(pPayload, pSrc, n);
+    }else{
+      memset(pPayload, 0, n);
+    }
+    nPayload -= n;
+    if( nPayload<=0 ) break;
+    pPayload += n;
+    pSrc += n;
+    nSrc -= n;
+    spaceLeft -= n;
     if( spaceLeft==0 ){
+      MemPage *pOvfl = 0;
 #ifndef SQLITE_OMIT_AUTOVACUUM
       Pgno pgnoPtrmap = pgnoOvfl; /* Overflow page pointer-map entry page */
       if( pBt->autoVacuum ){
@@ -6350,30 +6387,6 @@ static int fillInCell(
       pPayload = &pOvfl->aData[4];
       spaceLeft = pBt->usableSize - 4;
     }
-    n = nPayload;
-    if( n>spaceLeft ) n = spaceLeft;
-
-    /* If pToRelease is not zero than pPayload points into the data area
-    ** of pToRelease.  Make sure pToRelease is still writeable. */
-    assert( pToRelease==0 || sqlite3PagerIswriteable(pToRelease->pDbPage) );
-
-    /* If pPayload is part of the data area of pPage, then make sure pPage
-    ** is still writeable */
-    assert( pPayload<pPage->aData || pPayload>=&pPage->aData[pBt->pageSize]
-            || sqlite3PagerIswriteable(pPage->pDbPage) );
-
-    if( nSrc>0 ){
-      if( n>nSrc ) n = nSrc;
-      assert( pSrc );
-      memcpy(pPayload, pSrc, n);
-    }else{
-      memset(pPayload, 0, n);
-    }
-    nPayload -= n;
-    pPayload += n;
-    pSrc += n;
-    nSrc -= n;
-    spaceLeft -= n;
   }
   releasePage(pToRelease);
   return SQLITE_OK;