From: drh <>
Date: Tue, 11 Jun 2024 22:47:33 +0000 (+0000)
Subject: A second approach to working on the round() function so that it gives a
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=83725149c5e5bc2851a222acc603f2eb6f919472;p=thirdparty%2Fsqlite.git

A second approach to working on the round() function so that it gives a
small boost to numbers that are ...49999999 such that they round up.

FossilOrigin-Name: 44dd632896e688a7d73707f43261577b237628a587800b94f1b77d3ab0cedc2e
---

diff --git a/manifest b/manifest
index 2724500b35..7e95f13f30 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Remove\ssome\sdead\sJS\scode\sand\supdate\ssome\sJS\sdocs.
-D 2024-06-11T17:04:43.812
+C A\ssecond\sapproach\sto\sworking\son\sthe\sround()\sfunction\sso\sthat\sit\sgives\sa\nsmall\sboost\sto\snumbers\sthat\sare\s...49999999\ssuch\sthat\sthey\sround\sup.
+D 2024-06-11T22:47:33.094
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -708,7 +708,7 @@ F src/delete.c cb766727c78e715f9fb7ec8a7d03658ed2a3016343ca687acfcec9083cdca500
 F src/expr.c af9c9242be0df17280faf36c9810339de9df3d7a64ac8d33a5190a1400086ee5
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 852f93c0ef995e0c2b8983059a2b97151c194cc8259e21f5bc2b7ac508348c2a
-F src/func.c 1f61e32e7a357e615b5d2e774bee563761fce4f2fd97ecb0f72c33e62a2ada5f
+F src/func.c a7c6f4af5fa85ece25e5ff3228d182b4928461aaf5e5450e3c6f88767ff01d64
 F src/global.c 61a419dd9e993b9be0f91de4c4ccf322b053eb829868e089f0321dd669be3b90
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
@@ -2195,8 +2195,11 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 06e6f64533563ab9c059b773e5f0d78085df716f2624e547b7259f6789c3ffe0
-R 79d342ace6fd539450d6954e121ef97a
-U stephan
-Z 878c1bfba19ab8a7570c53af656f275c
+P 6935ac71bad3d36cc519f0325ae4447a674f257309d020cdc0741160fcce0580
+R 20f10f21aa5a26361938ba3edec94cb0
+T *branch * round-up-2
+T *sym-round-up-2 *
+T -sym-trunk *
+U drh
+Z 72a6e77fd70156feb2a1bdd4868e4b54
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 214309359d..7bbac74375 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-6935ac71bad3d36cc519f0325ae4447a674f257309d020cdc0741160fcce0580
\ No newline at end of file
+44dd632896e688a7d73707f43261577b237628a587800b94f1b77d3ab0cedc2e
\ No newline at end of file
diff --git a/src/func.c b/src/func.c
index 8fcda11dc0..99949dd44e 100644
--- a/src/func.c
+++ b/src/func.c
@@ -435,40 +435,60 @@ static void substrFunc(
   }
 }
 
+/*
+** The library round() function is only available if
+** SQLITE_ENABLE_MATH_FUNCTIONS is defined.  Without that macro, we
+** have to grow our own.
+**
+** The sqlite3Round(x) routine only needs to deal with non-negative
+** numbers.
+*/
+#ifdef SQLITE_ENABLE_MATH_FUNCTIONS
+# define sqlite3Round(X) round(X)
+#else
+static double sqlite3Round(double x){
+  assert( x>=0.0 );
+  if( x>+4503599627370496.0 ){
+    return x;
+  }else{
+    sqlite3_int64 ii = (sqlite3_int64)(x+0.5);
+    return (double)ii;
+  }
+}
+#endif
+
 /*
 ** Implementation of the round() function
 */
 #ifndef SQLITE_OMIT_FLOATING_POINT
 static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
-  int n = 0;
-  double r;
-  char *zBuf;
+  int n = 0;        /* Second argument. Digits to the right of decimal point */
+  double r;         /* First argument.  Value to be rounded */
+  double rX = 1.0;  /* Scaling factor.  pow(10,n) */
+  double rSgn;      /* Sign of the first first */
+  static const double rTwoPowerMinus52 =  /* pow(2,-52) */
+                           2.220446049250313080847263336181640625e-16;
   assert( argc==1 || argc==2 );
   if( argc==2 ){
+    double rY = 10;
+    int i;
     if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
     n = sqlite3_value_int(argv[1]);
     if( n>30 ) n = 30;
     if( n<0 ) n = 0;
+    for(i=n, rY=10; i>0; i>>=1, rY=rY*rY){
+      if( i&1 ) rX *= rY;
+    }
   }
   if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
   r = sqlite3_value_double(argv[0]);
-  /* If Y==0 and X will fit in a 64-bit int,
-  ** handle the rounding directly,
-  ** otherwise use printf.
-  */
-  if( r<-4503599627370496.0 || r>+4503599627370496.0 ){
-    /* The value has no fractional part so there is nothing to round */
-  }else if( n==0 ){ 
-    r = (double)((sqlite_int64)(r+(r<0?-0.5:+0.5)));
+  if( r<0 ){
+    rSgn = -1.0;
+    r = -r;
   }else{
-    zBuf = sqlite3_mprintf("%!.*f",n,r);
-    if( zBuf==0 ){
-      sqlite3_result_error_nomem(context);
-      return;
-    }
-    sqlite3AtoF(zBuf, &r, sqlite3Strlen30(zBuf), SQLITE_UTF8);
-    sqlite3_free(zBuf);
+    rSgn = 1.0;
   }
+  r = rSgn*sqlite3Round(r*rX + rX*r*rTwoPowerMinus52)/rX;
   sqlite3_result_double(context, r);
 }
 #endif
@@ -2505,7 +2525,6 @@ static void piFunc(
   (void)argv;
   sqlite3_result_double(context, M_PI);
 }
-
 #endif /* SQLITE_ENABLE_MATH_FUNCTIONS */
 
 /*