[PATCH 2/2] strftime: fix a bug in yesterday's change

[Jim Meyering]

Yesterday's strftime change caused some problems.
It would have introduced a dozen or so failures in coreutils'
"make check" tests.

I've added the barest framework for testing -- just enough
to demonstrate the failure, and fixed the bug:

Note: the test module probably needs added dependencies,
but I had limited time for this.

>From 353179dd0bd257c9b62e9c6fc0565b2028890b55 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Mon, 21 Mar 2011 15:09:10 +0100
Subject: [PATCH 1/2] tests: add strftime-tests module

* tests/test-strftime.c: New file.
* modules/strftime-tests: New module.
---
 ChangeLog              |    6 +++
 modules/strftime-tests |   12 +++++++
 tests/test-strftime.c  |   82 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+), 0 deletions(-)
 create mode 100644 modules/strftime-tests
 create mode 100644 tests/test-strftime.c

diff --git a/ChangeLog b/ChangeLog
index 3b24b8b..a266bbe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-03-21  Jim Meyering  <address@hidden>
+
+       tests: add strftime-testing module
+       * tests/test-strftime.c: New file.
+       * modules/strftime-tests: New module.
+
 2011-03-20  Paul Eggert  <address@hidden>

        strftime: don't assume a byte count fits in 'int'
diff --git a/modules/strftime-tests b/modules/strftime-tests
new file mode 100644
index 0000000..96ad213
--- /dev/null
+++ b/modules/strftime-tests
@@ -0,0 +1,12 @@
+Files:
+tests/test-strftime.c
+tests/macros.h
+
+Depends-on:
+strftime
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-strftime
+check_PROGRAMS += test-strftime
diff --git a/tests/test-strftime.c b/tests/test-strftime.c
new file mode 100644
index 0000000..2578550
--- /dev/null
+++ b/tests/test-strftime.c
@@ -0,0 +1,82 @@
+/* Test that posixtime works as required.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Jim Meyering.  */
+
+#include <config.h>
+
+#include "strftime.h"
+
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+
+#include "macros.h"
+#define STREQ(a, b) (strcmp (a, b) == 0)
+
+struct posixtm_test
+{
+  time_t in;
+  int in_ns;
+  char const *fmt;
+  char const *exp;
+};
+
+static struct posixtm_test const T[] =
+  {
+    { 1300000000, 0,            "%F", "2011-03-13" },
+    { 0,          0,            NULL, NULL }
+  };
+
+int
+main (void)
+{
+  int fail = 0;
+  unsigned int i;
+
+  for (i = 0; T[i].fmt; i++)
+    {
+      char buf[1000];
+      time_t t = T[i].in;
+      struct tm *tm = gmtime (&t);
+      size_t n;
+      int utc = 1;
+
+      ASSERT (tm);
+
+      n = nstrftime (buf, sizeof buf, T[i].fmt, tm, utc, T[i].in_ns);
+      if (n == 0)
+        {
+          fail = 1;
+          printf ("nstrftime failed with format %s\n", T[i].fmt);
+        }
+
+      if (! STREQ (buf, T[i].exp))
+        {
+          fail = 1;
+          printf ("%s: result mismatch: got %s, expected %s\n",
+                  T[i].fmt, buf, T[i].exp);
+        }
+    }
+
+  return fail;
+}
+
+/*
+Local Variables:
+indent-tabs-mode: nil
+End:
+*/
--
1.7.4.1.514.ga171c


>From 7878398c3bb9a823d5faab79258d17ea598d13ef Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Mon, 21 Mar 2011 15:32:54 +0100
Subject: [PATCH 2/2] strftime: fix a bug in yesterday's change

* lib/strftime.c (add): Accommodate width's initial value of -1.
Otherwise, nstrftime would copy uninitialized data into
the result buffer.
---
 ChangeLog      |    5 +++++
 lib/strftime.c |    5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index a266bbe..39ec021 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2011-03-21  Jim Meyering  <address@hidden>

+       strftime: fix a bug in yesterday's change
+       * lib/strftime.c (add): Accommodate width's initial value of -1.
+       Otherwise, nstrftime would copy uninitialized data into
+       the result buffer.
+
        tests: add strftime-testing module
        * tests/test-strftime.c: New file.
        * modules/strftime-tests: New module.
diff --git a/lib/strftime.c b/lib/strftime.c
index 95d5bee..acebc9a 100644
--- a/lib/strftime.c
+++ b/lib/strftime.c
@@ -173,12 +173,13 @@ extern char *tzname[];
   do                                                                          \
     {                                                                         \
       size_t _n = (n);                                                        \
-      size_t _incr = _n < width ? width : _n;                                 \
+      size_t _w = (width < 0 ? 0 : width);                                    \
+      size_t _incr = _n < _w ? _w : _n;                                       \
       if (_incr >= maxsize - i)                                               \
         return 0;                                                             \
       if (p)                                                                  \
         {                                                                     \
-          if (digits == 0 && _n < width)                                      \
+          if (digits == 0 && _n < _w)                                         \
             {                                                                 \
               size_t _delta = width - _n;                                     \
               if (pad == L_('0'))                                             \
--
1.7.4.1.514.ga171c