From 59bf00cb54fa87425444013fb732f68be69f71a1 Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Sun, 8 Dec 2013 23:33:28 +0000
Subject: [PATCH] Another simplification to the OP_MakeRecord opcode, making it
 slightly faster and very slightly smaller.

FossilOrigin-Name: f2f5a3ce9d075c4b1ac586c5db3a623d9035402d
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/vdbe.c    | 29 +++++++++++++++++++----------
 3 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/manifest b/manifest
index 19fb8c1241..65c6431388 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Avoid\sunnecessary\scalls\sto\ssqlite3VarintLen()\sfrom\sthe\sOP_MakeRecord\sopcode.
-D 2013-12-08T22:59:29.482
+C Another\ssimplification\sto\sthe\sOP_MakeRecord\sopcode,\smaking\sit\sslightly\nfaster\sand\svery\sslightly\ssmaller.
+D 2013-12-08T23:33:28.824
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in e1a9b4258bbde53f5636f4e238c65b7e11459e2b
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -280,7 +280,7 @@ F src/update.c d1c2477dcf14d90999d1935af4efb4806553250b
 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269
 F src/util.c 76ed0519296e3f62e97e57dab1999e34184c8e49
 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179
-F src/vdbe.c 7f51e9d422aefe6bcbaf7bf680e0d4ca9f6288cb
+F src/vdbe.c 6ccb107de55a34b7676a9eaa0aeb827015723fa4
 F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644
 F src/vdbeInt.h 05fbda0e061dbc4aaa2709a8cccf3515c245b263
 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed
@@ -1146,7 +1146,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P fbcc1a3ebb016225c3580181c908a2904cc184a5
-R 09b58c480760cc431d5e01573bf9e4b3
+P 7a234fc3c5e7970ffe0b8d6ac33c26acb64b5c4d
+R 57ac1272f14efea499bd7c6c07bb251b
 U drh
-Z 1bf421a053293bdaa5254a0efb062c9a
+Z f1f04177179428a44e2d9de7658a5211
diff --git a/manifest.uuid b/manifest.uuid
index d22393ad7f..2faf99014f 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-7a234fc3c5e7970ffe0b8d6ac33c26acb64b5c4d
\ No newline at end of file
+f2f5a3ce9d075c4b1ac586c5db3a623d9035402d
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index b0b56c4567..5133591e3c 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2560,7 +2560,8 @@ case OP_MakeRecord: {
   int nField;            /* Number of fields in the record */
   char *zAffinity;       /* The affinity string for the record */
   int file_format;       /* File format to use for encoding */
-  int i;                 /* Space used in zNewRecord[] */
+  int i;                 /* Space used in zNewRecord[] header */
+  int j;                 /* Space used in zNewRecord[] content */
   int len;               /* Length of a field */
 
   /* Assuming the record contains N fields, the record format looks
@@ -2597,17 +2598,21 @@ case OP_MakeRecord: {
   /* Loop through the elements that will make up the record to figure
   ** out how much space is required for the new record.
   */
-  for(pRec=pData0; pRec<=pLast; pRec++){
+  assert( pData0<=pLast );
+  pRec = pData0;
+  do{
     assert( memIsValid(pRec) );
     if( zAffinity ){
       applyAffinity(pRec, zAffinity[pRec-pData0], encoding);
     }
-    if( pRec->flags&MEM_Zero && pRec->n>0 ){
+    if( (pRec->flags&MEM_Zero)!=0 && pRec->n>0 ){
       sqlite3VdbeMemExpandBlob(pRec);
     }
     serial_type = sqlite3VdbeSerialType(pRec, file_format);
     len = sqlite3VdbeSerialTypeLen(serial_type);
     nData += len;
+    testcase( serial_type==127 );
+    testcase( serial_type==128 );
     nHdr += serial_type<=127 ? 1 : sqlite3VarintLen(serial_type);
     if( pRec->flags & MEM_Zero ){
       /* Only pure zero-filled BLOBs can be input to this Opcode.
@@ -2616,9 +2621,11 @@ case OP_MakeRecord: {
     }else if( len ){
       nZero = 0;
     }
-  }
+  }while( (++pRec)<=pLast );
 
   /* Add the initial header varint and total the size */
+  testcase( nHdr==126 );
+  testcase( nHdr==127 );
   if( nHdr<=126 ){
     /* The common case */
     nHdr += 1;
@@ -2645,14 +2652,16 @@ case OP_MakeRecord: {
 
   /* Write the record */
   i = putVarint32(zNewRecord, nHdr);
-  for(pRec=pData0; pRec<=pLast; pRec++){
+  j = nHdr;
+  assert( pData0<=pLast );
+  pRec = pData0;
+  do{
     serial_type = sqlite3VdbeSerialType(pRec, file_format);
     i += putVarint32(&zNewRecord[i], serial_type);      /* serial type */
-  }
-  for(pRec=pData0; pRec<=pLast; pRec++){  /* serial data */
-    i += sqlite3VdbeSerialPut(&zNewRecord[i], (int)(nByte-i), pRec,file_format);
-  }
-  assert( i==nByte );
+    j += sqlite3VdbeSerialPut(&zNewRecord[j], (int)(nByte-j), pRec,file_format);
+  }while( (++pRec)<=pLast );
+  assert( i==nHdr );
+  assert( j==nByte );
 
   assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
   pOut->n = (int)nByte;