Replace the atoi() library routine with a faster home-grown version in the

VDBE.  This gives a dramatic speed improvement for some kinds of queries. (CVS 784)

FossilOrigin-Name: 263a8ca40f7ff66fbdcb43bf9032391d5b1e68bd

manifest

@@ -1,5 +1,5 @@
-C Two\soptimizations\sto\sthe\spager:\s(1)\sWrite\sdirty\spages\sback\sto\sthe\sdatabase\nfile\sin\sorder\sand\s(2)\sKeep\sa\sseparate\slist\sof\sin-memory\spages\sthat\sare\sin\nthe\scheckpoint\sjournal\sin\sorder\sto\sspeed\sa\scheckpoint\scommit.\s(CVS\s783)
-D 2002-11-10T23:32:57
+C Replace\sthe\satoi()\slibrary\sroutine\swith\sa\sfaster\shome-grown\sversion\sin\sthe\nVDBE.\s\sThis\sgives\sa\sdramatic\sspeed\simprovement\sfor\ssome\skinds\sof\squeries.\s(CVS\s784)
+D 2002-11-11T00:05:43
 F Makefile.in d6c9a85c2a5e696843201d090dcf8bf2f8716f2a
 F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
 F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@@ -52,7 +52,7 @@ F src/tokenize.c 75e3bb37305b64e118e709752066f494c4f93c30
 F src/trigger.c 5ba917fc226b96065108da28186c2efaec53e481
 F src/update.c 881e4c8e7c786545da4fd2d95da19252b2e31137
 F src/util.c ca7650ef2cc2d50241e48029fca109a3016144ee
-F src/vdbe.c a187467bc4e9ef7793969b5010d7297341b19394
+F src/vdbe.c 7d46f087c1da55ba9be38f70d92a03c52c8a2ccb
 F src/vdbe.h b7584044223104ba7896a7f87b66daebdd6022ba
 F src/where.c 615a0f0bed305bcb27073c69347ea75018e8b58d
 F test/all.test efd958d048c70a3247997c482f0b33561f7759f0
@@ -149,7 +149,7 @@ F www/speed.tcl a20a792738475b68756ea7a19321600f23d1d803
 F www/sqlite.tcl ae3dcfb077e53833b59d4fcc94d8a12c50a44098
 F www/tclsqlite.tcl 1db15abeb446aad0caf0b95b8b9579720e4ea331
 F www/vdbe.tcl 2013852c27a02a091d39a766bc87cff329f21218
-P a29d60ecc5ee3f535142a81f56eecbef7875ef22
-R 52d1e18697b72d70d44fdac37bed7445
+P a6ef6657a4377684dc2fce7be2bbf009fd2d2f37
+R 185b0bc33f10b4a768e6cfb7280605c4
 U drh
-Z 7623b80b72f443af5ce24d861a13e847
+Z f3f9009eb197efb6353cb5684648e29d

manifest.uuid

@@ -1 +1 @@
-a6ef6657a4377684dc2fce7be2bbf009fd2d2f37
+263a8ca40f7ff66fbdcb43bf9032391d5b1e68bd

src/vdbe.c

@@ -36,7 +36,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.183 2002/11/01 01:55:38 drh Exp $
+** $Id: vdbe.c,v 1.184 2002/11/11 00:05:43 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -834,6 +834,33 @@ static void hardRelease(Vdbe *p, int i){
   p->aStack[i].flags &= ~(STK_Str|STK_Dyn|STK_Static|STK_Ephem);
 }
 
+/*
+** Return TRUE if zNum is an integer and write
+** the value of the integer into *pNum.
+**
+** Under Linux (RedHat 7.2) this routine is much faster than atoi()
+** for converting strings into integers.
+*/
+static int toInt(const char *zNum, int *pNum){
+  int v = 0;
+  int neg;
+  if( *zNum=='-' ){
+    neg = 1;
+    zNum++;
+  }else if( *zNum=='+' ){
+    neg = 0;
+    zNum++;
+  }else{
+    neg = 0;
+  }
+  while( isdigit(*zNum) ){
+    v = v*10 + *zNum - '0';
+    zNum++;
+  }
+  *pNum = neg ? -v : v;
+  return *zNum==0;
+}
+
 /*
 ** Convert the given stack entity into a integer if it isn't one
 ** already.
@@ -848,7 +875,7 @@ static void hardIntegerify(Vdbe *p, int i){
     p->aStack[i].i = (int)p->aStack[i].r;
     Release(p, i);
   }else if( p->aStack[i].flags & STK_Str ){
-    p->aStack[i].i = atoi(p->zStack[i]);
+    toInt(p->zStack[i], &p->aStack[i].i);
     Release(p, i);
   }else{
     p->aStack[i].i = 0;
@@ -967,15 +994,6 @@ static int isNumber(const char *zNum){
   return *zNum==0;
 }
 
-/*
-** Return TRUE if zNum is an integer.
-*/
-static int isInteger(const char *zNum){
-  if( *zNum=='-' || *zNum=='+' ) zNum++;
-  while( isdigit(*zNum) ) zNum++;
-  return *zNum==0;
-}
-
 /*
 ** Delete a keylist
 */
@@ -2109,10 +2127,11 @@ case OP_MustBeInt: {
     }
     aStack[tos].i = i;
   }else if( aStack[tos].flags & STK_Str ){
-    if( !isInteger(zStack[tos]) ){
+    int v;
+    if( !toInt(zStack[tos], &v) ){
       goto mismatch;
     }
-    p->aStack[tos].i = atoi(p->zStack[tos]);
+    p->aStack[tos].i = v;
   }else{
     goto mismatch;
   }
@@ -2250,7 +2269,7 @@ case OP_Gt:
 case OP_Ge: {
   int tos = p->tos;
   int nos = tos - 1;
-  int c;
+  int c, v;
   int ft, fn;
   VERIFY( if( nos<0 ) goto not_enough_stack; )
   ft = aStack[tos].flags;
@@ -2267,11 +2286,15 @@ case OP_Ge: {
     break;
   }else if( (ft & fn & STK_Int)==STK_Int ){
     c = aStack[nos].i - aStack[tos].i;
-  }else if( (ft & STK_Int)!=0 && (fn & STK_Str)!=0 && isInteger(zStack[nos]) ){
-    Integerify(p, nos);
+  }else if( (ft & STK_Int)!=0 && (fn & STK_Str)!=0 && toInt(zStack[nos],&v) ){
+    Release(p, nos);
+    aStack[nos].i = v;
+    aStack[nos].flags = STK_Int;
     c = aStack[nos].i - aStack[tos].i;
-  }else if( (fn & STK_Int)!=0 && (ft & STK_Str)!=0 && isInteger(zStack[tos]) ){
-    Integerify(p, tos);
+  }else if( (fn & STK_Int)!=0 && (ft & STK_Str)!=0 && toInt(zStack[tos],&v) ){
+    Release(p, tos);
+    aStack[tos].i = v;
+    aStack[tos].flags = STK_Int;
     c = aStack[nos].i - aStack[tos].i;
   }else{
     if( Stringify(p, tos) || Stringify(p, nos) ) goto no_mem;
@@ -4274,7 +4297,7 @@ case OP_IntegrityCk: {
   nRoot = sqliteHashCount(&pSet->hash);
   aRoot = sqliteMalloc( sizeof(int)*(nRoot+1) );
   for(j=0, i=sqliteHashFirst(&pSet->hash); i; i=sqliteHashNext(i), j++){
-    aRoot[j] = atoi((char*)sqliteHashKey(i));
+    toInt((char*)sqliteHashKey(i), &aRoot[j]);
   }
   aRoot[j] = 0;
   z = sqliteBtreeIntegrityCheck(pOp->p2 ? db->pBeTemp : pBt, aRoot, nRoot);