Small performance increase and size reduction in sqlite3FpDecode() by using

local variables instead of structure elements.

FossilOrigin-Name: b4c378bba582205aa676e45b21ffa17ad6199e2a017ec73cf41a0243f693b589

diff --git a/manifest b/manifest
index 30469cdd112f4c2390069f36bd668cc1a135a156..d449f79dbe3ad6c81e0b20cfae6a848f5c9d2568 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Inconsequential\schanges\sto\sfloating-point\sconversion,\samounting\sto\smere\ncode\scleanup\sto\said\scomprehension.
-D 2026-02-20T20:43:25.912
+C Small\sperformance\sincrease\sand\ssize\sreduction\sin\ssqlite3FpDecode()\sby\susing\nlocal\svariables\sinstead\sof\sstructure\selements.
+D 2026-02-21T00:20:29.013
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -803,7 +803,7 @@ F src/trigger.c a40440614bdf523090cc07223f4878f7e3c892bcd1a13afe18f90190daa5945d
 F src/update.c 3e5e7ff66fa19ebe4d1b113d480639a24cc1175adbefabbd1a948a07f28e37cf
 F src/upsert.c 215328c3f91623c520ec8672c44323553f12caeb4f01b1090ebdca99fdf7b4f1
 F src/utf.c 7267c3fb9e2467020507601af3354c2446c61f444387e094c779dccd5ca62165
-F src/util.c 64c047521e35adc402e6f2a8dcd20732392c02641418becfc4387a1c02f5e042
+F src/util.c 2578230d8c15e11cb86b7e6c4c069e5ea880a058d1d9aa25887fb607ac6942cd
 F src/vacuum.c d3d35d8ae893d419ade5fa196d761a83bddcbb62137a1a157ae751ef38b26e82
 F src/vdbe.c 5328c99dd256ee8132383565a86e253543a85daccfd7477c52f20bac6b385a7f
 F src/vdbe.h 966d0677a540b7ea6549b7c4e1312fc0d830fce3a235a58c801f2cc31cf5ecf9
@@ -2195,8 +2195,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh d924598cf2f55a4ecbc2aeb055c10bd5f48114793e7ba25f9585435da29e7e98
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P cb24edf1afc3f9083a4963c5fe232933eccc7c0cb8872aa5fcd336d226b885ef
-R 5dc7d1cf9df5b4fd3583425b84bcab00
+P 6d9c29123b6b143b0f7c8f5d018f170c72edfc5b1a4d67edd45e5552def2af6c
+R ab113b7f537cba0046252b74a0cfbdbd
 U drh
-Z a28f337e825428b6e4dfea35f10cb54e
+Z eb44db8829fa7401363a7a2fe662819e
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index f7d89da18276dbabfaebc53199816c38e46c7fcd..fa0737e469654207af2a06730185daf0821d9771 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-6d9c29123b6b143b0f7c8f5d018f170c72edfc5b1a4d67edd45e5552def2af6c
+b4c378bba582205aa676e45b21ffa17ad6199e2a017ec73cf41a0243f693b589

diff --git a/src/util.c b/src/util.c
index c39a1da16bcb0fd14b97a74e15063d11aad3820d..e0de0abf07000d4e75310d273f83aa2f688ac0bf 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -1174,9 +1174,10 @@ int sqlite3Atoi(const char *z){
 ** The p->z[] array is *not* zero-terminated.
 */
 void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
-  int i;
+  int i, n;
   u64 v;
   int e, exp = 0;
+  char *zBuf;
 
   p->isSpecial = 0;
   p->z = p->zBuf;
@@ -1206,9 +1207,9 @@ void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
   }
   v &= 0x000fffffffffffffULL;
   if( e==0 ){
-    int n = countLeadingZeros(v);
-    v <<= n;
-    e = -1074 - n;
+    int nn = countLeadingZeros(v);
+    v <<= nn;
+    e = -1074 - nn;
   }else{
     v = (v<<11) | U64_BIT(63);
     e -= 1086;
@@ -1217,38 +1218,39 @@ void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
 
   /* Extract significant digits. */
   i = sizeof(p->zBuf)-1;
+  zBuf = p->zBuf;
   assert( v>0 );
   while( v>=10 ){
     int kk = (v%100)*2;
     assert( TWO_BYTE_ALIGNMENT(&sqlite3DigitPairs.a[kk]) );
-    assert( TWO_BYTE_ALIGNMENT(&p->zBuf[i-1]) );
-    *(u16*)(&p->zBuf[i-1]) = *(u16*)&sqlite3DigitPairs.a[kk];
+    assert( TWO_BYTE_ALIGNMENT(&zBuf[i-1]) );
+    *(u16*)(&zBuf[i-1]) = *(u16*)&sqlite3DigitPairs.a[kk];
     i -= 2;
     v /= 100;
   }
   if( v ){
     assert( v<10 );
-    p->zBuf[i--] = v + '0';
+    zBuf[i--] = v + '0';
   }
   assert( i>=0 && i<sizeof(p->zBuf)-1 );
-  p->n = sizeof(p->zBuf) - 1 - i;
-  assert( p->n>0 );
-  assert( p->n<sizeof(p->zBuf) );
-  testcase( p->n==sizeof(p->zBuf)-1 );
-  p->iDP = p->n + exp;
+  n = sizeof(p->zBuf) - 1 - i;
+  assert( n>0 );
+  assert( n<sizeof(p->zBuf) );
+  testcase( n==sizeof(p->zBuf)-1 );
+  p->iDP = n + exp;
   if( iRound<=0 ){
     iRound = p->iDP - iRound;
-    if( iRound==0 && p->zBuf[i+1]>='5' ){
+    if( iRound==0 && zBuf[i+1]>='5' ){
       iRound = 1;
-      p->zBuf[i--] = '0';
-      p->n++;
+      zBuf[i--] = '0';
+      n++;
       p->iDP++;
     }
   }
-  if( iRound>0 && (iRound<p->n || p->n>mxRound) ){
-    char *z = &p->zBuf[i+1];
+  if( iRound>0 && (iRound<n || n>mxRound) ){
+    char *z = &zBuf[i+1];
     if( iRound>mxRound ) iRound = mxRound;
-    p->n = iRound;
+    n = iRound;
     if( z[iRound]>='5' ){
       int j = iRound-1;
       while( 1 /*exit-by-break*/ ){
@@ -1257,7 +1259,7 @@ void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
         z[j] = '0';
         if( j==0 ){
           p->z[i--] = '1';
-          p->n++;
+          n++;
           p->iDP++;
           break;
         }else{
@@ -1266,13 +1268,15 @@ void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
       }
     }
   }
-  p->z = &p->zBuf[i+1];
-  assert( i+p->n < sizeof(p->zBuf) );
-  assert( p->n>0 );
-  while( p->z[p->n-1]=='0' ){
-    p->n--;
-    assert( p->n>0 );
+  p->z = &zBuf[i+1];
+  assert( i+n < sizeof(p->zBuf) );
+  assert( n>0 );
+  zBuf = p->z;
+  while( zBuf[n-1]=='0' ){
+    n--;
+    assert( n>0 );
   }
+  p->n = n;
 }
 
 /*