[PATCH] Return minus_zero for strtod ("-0", NULL)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

Until recently strtod ("-0", NULL) returned -0.0, not because the code
tried to handle it, but because of a bug:
http://sourceware.org/cgi-bin/cvsweb.cgi/libc/stdlib/strtod_l.c.diff?cvsroot=glibc&r1=1.16&r2=1.18
When we don't take any of the shortpaths, round_and_return still return
-0.0, so I think we should handle it even in the shortpaths.
strtod ("-0.0", NULL) even in current glibc returns -0.0.

2007-08-03  Jakub Jelinek  <jakub@redhat.com>

	* stdlib/strtod_l.c (____STRTOF_INTERNAL): Properly handle -0.
	* stdlib/Makefile (tests): Add tst-strtod5.
	(tst-strtod5-ENV): New.
	* stdlib/tst-strtod5.c: New test.

--- libc/stdlib/strtod_l.c.jj	2007-02-22 08:46:24.000000000 +0100
+++ libc/stdlib/strtod_l.c	2007-08-03 17:56:30.000000000 +0200
@@ -700,7 +700,8 @@ ____STRTOF_INTERNAL (nptr, endptr, group
 #endif
       /* If TP is at the start of the digits, there was no correctly
 	 grouped prefix of the string; so no number found.  */
-      RETURN (0.0, tp == start_of_digits ? (base == 16 ? cp - 1 : nptr) : tp);
+      RETURN (negative ? -0.0 : 0.0,
+	      tp == start_of_digits ? (base == 16 ? cp - 1 : nptr) : tp);
     }
 
   /* Remember first significant digit and read following characters until the
@@ -759,7 +760,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group
 	  if (tp < startp)
 	    /* The number is validly grouped, but consists
 	       only of zeroes.  The whole value is zero.  */
-	    RETURN (0.0, tp);
+	    RETURN (negative ? -0.0 : 0.0, tp);
 
 	  /* Recompute DIG_NO so we won't read more digits than
 	     are properly grouped.  */
@@ -862,7 +863,7 @@ ____STRTOF_INTERNAL (nptr, endptr, group
 		    {
 		      /* Overflow or underflow.  */
 		      __set_errno (ERANGE);
-		      result = (exp_negative ? 0.0 :
+		      result = (exp_negative ? (negative ? -0.0 : 0.0) :
 				negative ? -FLOAT_HUGE_VAL : FLOAT_HUGE_VAL);
 		    }
 
--- libc/stdlib/Makefile.jj	2007-01-15 23:25:30.000000000 +0100
+++ libc/stdlib/Makefile	2007-08-03 18:12:18.000000000 +0200
@@ -68,7 +68,7 @@ tests		:= tst-strtol tst-strtod testmb t
 		   tst-limits tst-rand48 bug-strtod tst-setcontext	    \
 		   test-a64l tst-qsort tst-system testmb2 bug-strtod2	    \
 		   tst-atof1 tst-atof2 tst-strtod2 tst-strtod3 tst-rand48-2 \
-		   tst-makecontext tst-strtod4
+		   tst-makecontext tst-strtod4 tst-strtod5
 
 include ../Makeconfig
 
@@ -115,6 +115,7 @@ test-canon-ARGS = --test-dir=${common-ob
 tst-strtod-ENV = LOCPATH=$(common-objpfx)localedata
 tst-strtod3-ENV = LOCPATH=$(common-objpfx)localedata
 tst-strtod4-ENV = LOCPATH=$(common-objpfx)localedata
+tst-strtod5-ENV = LOCPATH=$(common-objpfx)localedata
 testmb2-ENV = LOCPATH=$(common-objpfx)localedata
 
 # Run a test on the header files we use.
--- libc/stdlib/tst-strtod5.c.jj	2007-08-03 18:03:43.000000000 +0200
+++ libc/stdlib/tst-strtod5.c	2007-08-03 18:21:37.000000000 +0200
@@ -0,0 +1,88 @@
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#define NBSP "\xc2\xa0"
+
+static const struct
+{
+  const char *in;
+  int group;
+  double expected;
+} tests[] =
+  {
+    { "0", 0, 0.0 },
+    { "000", 0, 0.0 },
+    { "-0", 0, -0.0 },
+    { "-000", 0, -0.0 },
+    { "0,", 0, 0.0 },
+    { "-0,", 0, -0.0 },
+    { "0,0", 0, 0.0 },
+    { "-0,0", 0, -0.0 },
+    { "0e-10", 0, 0.0 },
+    { "-0e-10", 0, -0.0 },
+    { "0,e-10", 0, 0.0 },
+    { "-0,e-10", 0, -0.0 },
+    { "0,0e-10", 0, 0.0 },
+    { "-0,0e-10", 0, -0.0 },
+    { "0e-1000000", 0, 0.0 },
+    { "-0e-1000000", 0, -0.0 },
+    { "0,0e-1000000", 0, 0.0 },
+    { "-0,0e-1000000", 0, -0.0 },
+    { "0", 1, 0.0 },
+    { "000", 1, 0.0 },
+    { "-0", 1, -0.0 },
+    { "-000", 1, -0.0 },
+    { "0e-10", 1, 0.0 },
+    { "-0e-10", 1, -0.0 },
+    { "0e-1000000", 1, 0.0 },
+    { "-0e-1000000", 1, -0.0 },
+    { "000"NBSP"000"NBSP"000", 1, 0.0 },
+    { "-000"NBSP"000"NBSP"000", 1, -0.0 }
+  };
+#define NTESTS (sizeof (tests) / sizeof (tests[0]))
+
+
+static int
+do_test (void)
+{
+  if (setlocale (LC_ALL, "cs_CZ.UTF-8") == NULL)
+    {
+      puts ("could not set locale");
+      return 1;
+    }
+
+  int status = 0;
+
+  for (int i = 0; i < NTESTS; ++i)
+    {
+      char *ep;
+      double r;
+
+      if (tests[i].group)
+	r = __strtod_internal (tests[i].in, &ep, 1);
+      else
+	r = strtod (tests[i].in, &ep);
+
+      if (*ep != '\0')
+	{
+	  printf ("%d: got rest string \"%s\", expected \"\"\n", i, ep);
+	  status = 1;
+	}
+
+      if (r != tests[i].expected
+	  || copysign (10.0, r) != copysign (10.0, tests[i].expected))
+	{
+	  printf ("%d: got wrong results %g, expected %g\n",
+		  i, r, tests[i].expected);
+	  status = 1;
+	}
+    }
+
+  return status;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

	Jakub