From: drh <>
Date: Sat, 7 Dec 2024 19:06:25 +0000 (+0000)
Subject: A cleaner and more robust solution to the floating-point conversion problem
X-Git-Tag: major-relase~78
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8703642803df6dc3920239ed85654e92b4cc5451;p=thirdparty%2Fsqlite.git

A cleaner and more robust solution to the floating-point conversion problem
originally fixed by [81342fa6dd03fffb].

FossilOrigin-Name: 351de57f80b73045448c71d3402d877ff5d72418b1f5fc34c8147a04f7c5cb78
---

diff --git a/manifest b/manifest
index 1442a766fd..8c3849164d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\smore\sharmless\scompiler\swarnings.
-D 2024-12-07T17:08:13.773
+C A\scleaner\sand\smore\srobust\ssolution\sto\sthe\sfloating-point\sconversion\sproblem\noriginally\sfixed\sby\s[81342fa6dd03fffb].
+D 2024-12-07T19:06:25.786
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -844,7 +844,7 @@ F src/trigger.c 0bb986a5b96047fd597c6aac28588853df56064e576e6b81ba777ef2ccaac461
 F src/update.c 0e01aa6a3edf9ec112b33eb714b9016a81241497b1fb7c3e74332f4f71756508
 F src/upsert.c 215328c3f91623c520ec8672c44323553f12caeb4f01b1090ebdca99fdf7b4f1
 F src/utf.c 8b29d9a5956569ea2700f869669b8ef67a9662ee5e724ff77ab3c387e27094ba
-F src/util.c 196a1498ed9ab5d3cca55db73ba10348c058c840b0a534e9d5d90db1862a50a1
+F src/util.c bf4e641c1e2d5cf40501f5f6990df412d2b6c301880a74750e7eefc4315f72bc
 F src/vacuum.c b763b6457bd058d2072ef9364832351fd8d11e8abf70cbb349657360f7d55c40
 F src/vdbe.c 8a6eb02823b424b273614bae41579392a5c495424592b60423dd2c443a583df0
 F src/vdbe.h 9676348d342bd04e21e384c63b57224171ce84fac77853357334ef94c4d33cf4
@@ -2202,8 +2202,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 462700aeb7c183d739ead4d726ce5384b3297bcf7929abd010987fa3a5f64807
-R 9ca7022ab896402e14e56ef4a0122fef
+P f5b8fd77635e5e6d2d88a1ce74e1bd6c4311260a2b695e5055b898b880bf5718
+R 8f59f36dbcd9cf41cdce9fb59aaabbba
 U drh
-Z 5b81dd5db542d45ebbd1ee1a952722cd
+Z 7774bee9e6cea167bb38890889846afb
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index db4908810c..24849f9a8a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-f5b8fd77635e5e6d2d88a1ce74e1bd6c4311260a2b695e5055b898b880bf5718
+351de57f80b73045448c71d3402d877ff5d72418b1f5fc34c8147a04f7c5cb78
diff --git a/src/util.c b/src/util.c
index bb676c5fbb..e134f7a7d8 100644
--- a/src/util.c
+++ b/src/util.c
@@ -539,6 +539,7 @@ int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
   int eValid = 1;  /* True exponent is either not used or is well-formed */
   int nDigit = 0;  /* Number of digits processed */
   int eType = 1;   /* 1: pure integer,  2+: fractional  -1 or less: bad UTF16 */
+  u64 s2;          /* round-tripped significand */
   double rr[2];
 
   assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
@@ -652,16 +653,16 @@ do_atof_calc:
   }
 
   rr[0] = (double)s;
-  if( s<(LARGEST_UINT64-0x7ff) ){
-    u64 s2 = (u64)rr[0];
-#if defined(_MSC_VER) && _MSC_VER<1700
-    if( s2==0x8000000000000000LL ){ s2 = 2*(u64)(0.5*rr[0]); }
-#endif
-    rr[1] = s>=s2 ? (double)(s - s2) : -(double)(s2 - s);
-  }else{
+  s2 = (u64)rr[0];
+  rr[1] = s>=s2 ? (double)(s - s2) : -(double)(s2 - s);
+  if( rr[1]>1e-10*rr[0] ){
+    /* On some floating-point processing units, doing the round
+    ** trip from u64 to double back to u64 can give a wonky value
+    ** when the original u64 is close to LARGEST_UINT64.  If we
+    ** did get an overly large error value, just set it to zero. */
     rr[1] = 0.0;
   }
-
+  
   if( e>0 ){
     while( e>=100  ){
       e -= 100;