From: drh <drh@noemail.net>
Date: Tue, 19 Jun 2012 03:11:25 +0000 (+0000)
Subject: Improved accuracy on text-to-real and real-to-text conversions.  Most
X-Git-Tag: version-3.7.14~74^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=72b3fbc7b5b5bbe783ca6a6b14532770f6eb011d;p=thirdparty%2Fsqlite.git

Improved accuracy on text-to-real and real-to-text conversions.  Most
conversions now round-trip correctly.  Still need to fix some corner
cases.

FossilOrigin-Name: 8ecffca900cd6a8922001fd458a266ce8c83fb66
---

diff --git a/manifest b/manifest
index 9606896e10..92463ef29e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improved\srounding\saccuracy\son\stest-to-float\sconversions.
-D 2012-06-19T00:45:16.776
+C Improved\saccuracy\son\stext-to-real\sand\sreal-to-text\sconversions.\s\sMost\nconversions\snow\sround-trip\scorrectly.\s\sStill\sneed\sto\sfix\ssome\scorner\ncases.
+D 2012-06-19T03:11:25.621
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in d17fddaa4e81f93a7c9c7c0808aacb3fc95f79f4
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -135,7 +135,7 @@ F src/delete.c 4c20ea4f6213b3bc1c6a510586864b679946e05e
 F src/expr.c 06a7733d19dc725dc46ba51afd9feadb4b85d991
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c 657212460bf5cfd3ae607d12ea62092844c227b5
-F src/func.c c6b3c94320253a35bda43fb69cc292618e3285d6
+F src/func.c 22a180ac02e725a16aed586c3ae1c1c0f7c79cfd
 F src/global.c 4cfdca5cb0edd33c4d021baec4ede958cb2c793b
 F src/hash.c 458488dcc159c301b8e7686280ab209f1fb915af
 F src/hash.h 2894c932d84d9f892d4b4023a75e501f83050970
@@ -174,7 +174,7 @@ F src/pcache.h 1b5dcc3dc8103d03e625b177023ee67764fa6b7c
 F src/pcache1.c 2234d84f9c003d800a57f00f8535c91667fa4f6c
 F src/pragma.c eee3e3161f82a1e06f632a8d2a82b29ba3c45889
 F src/prepare.c 33291b83cca285718048d219c67b8298501fa3a5
-F src/printf.c 7ffb4ebb8b341f67e049695ba031da717b3d2699
+F src/printf.c 263748c3b1e41f9f16a567ef2cbe4cf95b897a1a
 F src/random.c cd4a67b3953b88019f8cd4ccd81394a8ddfaba50
 F src/resolve.c b3c70ab28cac60de33684c9aa9e5138dcf71d6dd
 F src/rowset.c f6a49f3e9579428024662f6e2931832511f831a1
@@ -274,7 +274,7 @@ F test/async2.test c0a9bd20816d7d6a2ceca7b8c03d3d69c28ffb8b
 F test/async3.test d73a062002376d7edc1fe3edff493edbec1fc2f7
 F test/async4.test 1787e3952128aa10238bf39945126de7ca23685a
 F test/async5.test 0dd8701bd588bf6e70c2557a22ae3f22b2567b4c
-F test/atof1.test 1f6dc0f47f6697e32fa51dd154412e1172984928
+F test/atof1.test 6e6d41337133cb98e61262fa385780e04e9de165
 F test/attach.test 0d112b7713611fdf0340260192749737135fda5f
 F test/attach2.test e54436ed956d3d88bdee61221da59bf3935a0966
 F test/attach3.test d89ccfe4fe6e2b5e368d480fcdfe4b496c54cf4e
@@ -364,7 +364,7 @@ F test/crashtest1.c 09c1c7d728ccf4feb9e481671e29dda5669bbcc2
 F test/createtab.test b5de160630b209c4b8925bdcbbaf48cc90b67fe8
 F test/cse.test 277350a26264495e86b1785f34d2d0c8600e021c
 F test/ctime.test 7bd009071e242aac4f18521581536b652b789a47
-F test/date.test a18a2ce81add84b17b06559e82ad7bb91bc6ddff
+F test/date.test f3228180c87bbe5d39c9397bf001c0095c3821b9
 F test/dbstatus.test 207e5b63fcb7b9c3bb8e1fdf38ebd4654ad0e54b
 F test/dbstatus2.test b1de8250fde1f3474d6b86f0e89de38d84794f56
 F test/default.test 6faf23ccb300114924353007795aa9a8ec0aa9dc
@@ -1006,7 +1006,10 @@ F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
-P 892b74116a3b23268895b96433d18ef00c1433d8
-R f92cf3b5f19c2cdf0a1f4043259e76e0
+P 699b792c6a0e989994549959b11ec1bfad8bbd92
+R 9adb61fbfc8a4b0255b08c19fe781f44
+T *branch * floating-point-conversions
+T *sym-floating-point-conversions *
+T -sym-trunk *
 U drh
-Z 37917877b4f7a2aac8f4f47ec8031274
+Z 93861bbc3afe941842927198b8f68ac0
diff --git a/manifest.uuid b/manifest.uuid
index 9a76fd8178..630caf4294 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-699b792c6a0e989994549959b11ec1bfad8bbd92
\ No newline at end of file
+8ecffca900cd6a8922001fd458a266ce8c83fb66
\ No newline at end of file
diff --git a/src/func.c b/src/func.c
index 6ffc7184b0..7aaef2b38f 100644
--- a/src/func.c
+++ b/src/func.c
@@ -863,8 +863,19 @@ static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
   assert( argc==1 );
   UNUSED_PARAMETER(argc);
   switch( sqlite3_value_type(argv[0]) ){
-    case SQLITE_INTEGER:
     case SQLITE_FLOAT: {
+      double r1, r2;
+      r1 = sqlite3_value_double(argv[0]);
+      char zBuf[50];
+      sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.15g", r1);
+      sqlite3AtoF(zBuf, &r2, 20, SQLITE_UTF8);
+      if( r1!=r2 ){
+        sqlite3_snprintf(sizeof(zBuf), zBuf, "%!.20e", r1);
+      }
+      sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
+      break;
+    }
+    case SQLITE_INTEGER: {
       sqlite3_result_value(context, argv[0]);
       break;
     }
diff --git a/src/printf.c b/src/printf.c
index 58cfd2bd41..75febb286f 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -124,7 +124,8 @@ static const et_info fmtinfo[] = {
 static char et_getdigit(LONGDOUBLE_TYPE *val, int *cnt){
   int digit;
   LONGDOUBLE_TYPE d;
-  if( (*cnt)++ >= 16 ) return '0';
+  if( (*cnt)<=0 ) return '0';
+  (*cnt)--;
   digit = (int)*val;
   d = digit;
   digit += '0';
@@ -428,9 +429,11 @@ void sqlite3VXPrintf(
           break;
         }
         if( realvalue>0.0 ){
-          while( realvalue>=1e32 && exp<=350 ){ realvalue *= 1e-32; exp+=32; }
-          while( realvalue>=1e8 && exp<=350 ){ realvalue *= 1e-8; exp+=8; }
-          while( realvalue>=10.0 && exp<=350 ){ realvalue *= 0.1; exp++; }
+          LONGDOUBLE_TYPE scale = 1.0;
+          while( realvalue>=1e64*scale && exp<=350 ){ scale *= 1e64; exp+=64; }
+          while( realvalue>=1e8*scale && exp<=350 ){ scale *= 1e8; exp+=8; }
+          while( realvalue>=10.0*scale && exp<=350 ){ scale *= 10.0; exp++; }
+          realvalue /= scale;
           while( realvalue<1e-8 ){ realvalue *= 1e8; exp-=8; }
           while( realvalue<1.0 ){ realvalue *= 10.0; exp--; }
           if( exp>350 ){
@@ -463,7 +466,7 @@ void sqlite3VXPrintf(
             xtype = etFLOAT;
           }
         }else{
-          flag_rtz = 0;
+          flag_rtz = flag_altform2;
         }
         if( xtype==etEXP ){
           e2 = 0;
@@ -478,7 +481,7 @@ void sqlite3VXPrintf(
           }
         }
         zOut = bufpt;
-        nsd = 0;
+        nsd = 16 + flag_altform2*10;
         flag_dp = (precision>0 ?1:0) | flag_alternateform | flag_altform2;
         /* The sign in front of the number */
         if( prefix ){
diff --git a/test/atof1.test b/test/atof1.test
index dff5e2a3d8..f1635789a6 100644
--- a/test/atof1.test
+++ b/test/atof1.test
@@ -17,10 +17,14 @@ source $testdir/tester.tcl
 
 expr srand(1)
 for {set i 1} {$i<10000} {incr i} {
-  do_test 1.$i {
-    set pow [expr {int((rand()-0.5)*100)}]
-    set x [expr {pow((rand()-0.5)*2*rand(),$pow)}]
-    set xf [format %.45e $x]
+  set pow [expr {int((rand()-0.5)*100)}]
+  set x [expr {pow((rand()-0.5)*2*rand(),$pow)}]
+  set xf [format %.32e $x]
+
+  # Verify that text->real conversions get exactly same ieee754 floating-
+  # point value in SQLite as they do in TCL.
+  #
+  do_test 1.$i.1 {
     set y [db eval "SELECT $xf=\$x"]
     if {!$y} {
       puts -nonewline \173[db eval "SELECT real2hex($xf), real2hex(\$x)"]\175
@@ -30,6 +34,26 @@ for {set i 1} {$i<10000} {incr i} {
     }
     set y
   } {1}
+
+  # FIX ME.  The following tests (real->text->real round-trips) sometimes
+  # fail for large floating-point values.  Skip them for now...
+  #
+  if {abs($x)>1e50} continue
+
+  # Verify that round-trip real->text->real conversions using the quote()
+  # function preserve the bits of the numeric value exactly.
+  #
+  do_test 1.$i.2 {
+    set y [db eval {SELECT $x=CAST(quote($x) AS real)}]
+    if {!$y} {
+      db eval {SELECT real2hex($x) a, real2hex(CAST(quote($x) AS real)) b} {}
+      puts "\nIN:    $a $xf"
+      puts [format {QUOTE: %16s %s} {} [db eval {SELECT quote($x)}]]
+      db eval {SELECT CAST(quote($x) AS real) c} {}
+      puts "OUT:   $b [format %.32e $c]"
+    }
+    set y
+  } {1}
 }
 
 
diff --git a/test/date.test b/test/date.test
index 9bfec12626..a30402c0d6 100644
--- a/test/date.test
+++ b/test/date.test
@@ -151,7 +151,7 @@ datetest 3.2.1 {strftime('pre%fpost','2003-10-31 12:34:56.432')} pre56.432post
 datetest 3.2.2 {strftime('%f','2003-10-31 12:34:59.9999999')} 59.999
 datetest 3.3 {strftime('%H','2003-10-31 12:34:56.432')} 12
 datetest 3.4 {strftime('%j','2003-10-31 12:34:56.432')} 304
-datetest 3.5 {strftime('%J','2003-10-31 12:34:56.432')} 2452944.02426426
+datetest 3.5 {strftime('%J','2003-10-31 12:34:56.432')} 2452944.024264259
 datetest 3.6 {strftime('%m','2003-10-31 12:34:56.432')} 10
 datetest 3.7 {strftime('%M','2003-10-31 12:34:56.432')} 34
 datetest 3.8.1 {strftime('%s','2003-10-31 12:34:56.432')} 1067603696