From: H.Merijn Brand <h.m.brand@xs4all.nl>
Date: Tue, 8 Jul 2008 20:00:24 +0000 (+0000)
Subject: Fine-grained sGMTIME_min/max detection
X-Git-Tag: 5.26.1~290
X-Git-Url: https://perl5.git.perl.org/metaconfig.git/commitdiff_plain/9b50610285ca710e1c177b9aea43da09b9d2a960?ds=sidebyside

Fine-grained sGMTIME_min/max detection

p4raw-id: //depot/metaconfig@34113
---

diff --git a/U/perl/time_size.U b/U/perl/time_size.U
index 0b206b9..c2b9611 100644
--- a/U/perl/time_size.U
+++ b/U/perl/time_size.U
@@ -5,7 +5,7 @@
 ?RCS: You may distribute under the terms of either the GNU General Public
 ?RCS: License or the Artistic License, as specified in the README file.
 ?RCS:
-?MAKE:sGMTIME_max sGMTIME_min: cat rm_try Setvar Compile run
+?MAKE:sGMTIME_max sGMTIME_min: cat rm_try Setvar Compile run i_values
 ?MAKE:	-pick add $@ %<
 ?S:sGMTIME_max:
 ?S:	This variable defines the maximum value of the time_t offset that
@@ -29,74 +29,84 @@
 ?D:sGMTIME_max=0
 ?D:sGMTIME_min=0
 ?F:!try
+?T:yyy
 : Check the max offset that gmtime accepts
-echo "Checking max offset that gmtime () accepts"
+echo "Checking max offsets that gmtime () accepts"
 
-$cat >try.c <<'EOCP'
+case $i_values in
+    define) yyy="#include <values.h>" ;;
+    *)      yyy="" ;;
+    esac
+
+$cat >try.c <<EOCP
 #include <sys/types.h>
 #include <stdio.h>
 #include <time.h>
-int main () {
-  struct tm *tmp;
-  int i, y = 0;
-  time_t pt = 0;
+$yyy
+
+int i;
+struct tm *tmp;
+time_t pt;
 
-  for (i = 0; i < 78; i++) {
-    time_t t = ((time_t)1 << i) - 1;
+void gm_check (time_t t)
+{
     tmp = gmtime (&t);
-    if (tmp == NULL || tmp->tm_year < y) {
-      i--;
-      printf ("%ld\n", pt);
-      return (i);
-      }
+    if (tmp == NULL || tmp->tm_year < -1900)
+	tmp = NULL;
+    else
+	pt = t;
+    } /* gm_check */
 
-    y = tmp->tm_year;
-    pt = t;
+int check_max ()
+{
+  tmp = NULL;
+  pt  = 0;
+#ifdef MAXLONG
+  gm_check (MAXLONG);
+#endif
+  if (tmp == NULL || tmp->tm_year < 0) {
+    for (i = 63; i >= 0; i--) {
+      time_t x = pt | ((time_t)1 << i);
+      if (x < 0) continue;
+      gm_check (x);
+      }
     }
-  printf ("%ld\n", pt);
+  printf ("sGMTIME_max=%ld\n", pt);
   return (0);
   }
-EOCP
-set try
-if eval $compile; then
-    sGMTIME_max=`$run ./try`
-else
-    echo "Cannot determine sGMTIME_max"
-    fi
-$rm_try
 
-echo "Checking min offset that gmtime () accepts"
-
-$cat >try.c <<'EOCP'
-#include <sys/types.h>
-#include <stdio.h>
-#include <time.h>
-int main () {
-  struct tm *tmp;
-  int i, y = 70;
-  time_t pt = 0;
-
-  for (i = 0; i < 78; i++) {
-    time_t t = - ((time_t)1 << i);
-    tmp = gmtime (&t);
-    if (tmp == NULL || tmp->tm_year > y) {
-      i--;
-      printf ("%ld\n", pt);
-      return (i);
+int check_min ()
+{
+  tmp = NULL;
+  pt  = 0;
+#ifdef MINLONG
+  gm_check (MINLONG);
+#endif
+  if (tmp == NULL) {
+    for (i = 36; i >= 0; i--) {
+      time_t x = pt - ((time_t)1 << i);
+      if (x > 0) continue;
+      gm_check (x);
       }
-
-    y = tmp->tm_year;
-    pt = t;
     }
-  printf ("%ld\n", pt);
+  printf ("sGMTIME_min=%ld\n", pt);
   return (0);
   }
+
+int main (int argc, char *argv[])
+{
+  fprintf (stderr, "Sizeof time_t = %ld\n", sizeof (time_t));
+  check_max ();
+  check_min ();
+  return (0);
+  } /* main */
 EOCP
 set try
 if eval $compile; then
-    sGMTIME_min=`$run ./try`
+    yyy=`$run ./try`
+    eval $yyy
 else
-    echo "Cannot determine sGMTIME_min"
+    echo "Cannot determine sGMTIME_max and sGMTIME_min." >&4
     fi
 $rm_try