Re: [Patch, libfortran] PR 47802 Implementation of CTIME intrinsic

[Janne Blomqvist <blomqvist dot janne at gmail dot com>]

On Wed, Feb 23, 2011 at 20:23, Tobias Burnus
<tobias.burnus@physik.fu-berlin.de> wrote:
> Janne Blomqvist wrote:
>> The attached patch changes the implementation of CTIME and FDATE to
>> use strftime instead.

> Âfdate_sub (char * date, gfc_charlen_type date_len)
> [...]
> + Âfctime (date, date_len, &now);
>
> As convenient as I find that one directly passes the buffer:
> Doesn't this reduce the number of characters effectively
> by one? Assume 'Sat Aug 19 18:13:14 1995'. That's 24 characters.
> If one now does:
> Âcharacter(len=24) :: str
> Âcall fdate(str)
> will this work? I fear that this will produce
> 'Sat Aug 19 18:13:14 199\0'. It seems to work is the string is
> at least one character longer than needed as then memset should
> get rid of the tailing '\0'.
>
>
> + Â not available, gmtime use thread-local storage so it's
>
> s/use/uses/
>
>
>
> libgfortran/intrinsics/time_1.h
> +static struct tm *
> +localtime_r (const time_t * timep, struct tm * result)
> +{
> + Â*result = *localtime (timep);
> + Âreturn result;
> +}
>
> Any reason that you do not mark it as inline?

Patch with the above improvements attached. Ok for trunk?

2011-02-24  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/47802
	* config.h.in: Regenerated.
	* configure: Regenerated.
	* configure.ac: Remove checks for ctime and ctime_r, add check for
	strftime.
	* intrinsics/date_and_time.c (localtime_r): Move fallback
	implementation to time_1.h.
	* intrinsics/time_1.h (localtime_r): Fallback implementation.
	* intrinsics/ctime.c: Include time_1.h.
	(ctime_r): Remove fallback implementation.
	(strctime): New function.
	(fdate): Use strctime instead of ctime_r.
	(fdate_sub): Likewise.
	(ctime): Likewise.
	(ctime_sub): Likewise.



-- 
Janne Blomqvist

diff --git a/libgfortran/configure.ac b/libgfortran/configure.ac
index d25a067..66468db 100644
--- a/libgfortran/configure.ac
+++ b/libgfortran/configure.ac
@@ -248,11 +248,11 @@ AC_CHECK_MEMBERS([struct stat.st_rdev])
 # Check for library functions.
 AC_CHECK_FUNCS(getrusage times mkstemp strtof strtold snprintf ftruncate chsize)
 AC_CHECK_FUNCS(chdir strerror getlogin gethostname kill link symlink perror)
-AC_CHECK_FUNCS(sleep time ttyname signal alarm ctime clock access fork execl)
+AC_CHECK_FUNCS(sleep time ttyname signal alarm clock access fork execl)
 AC_CHECK_FUNCS(wait setmode execvp pipe dup2 close fdopen strcasestr getrlimit)
 AC_CHECK_FUNCS(gettimeofday stat fstat lstat getpwuid vsnprintf dup getcwd)
-AC_CHECK_FUNCS(localtime_r gmtime_r strerror_r getpwuid_r ttyname_r ctime_r)
-AC_CHECK_FUNCS(clock_gettime)
+AC_CHECK_FUNCS(localtime_r gmtime_r strerror_r getpwuid_r ttyname_r)
+AC_CHECK_FUNCS(clock_gettime strftime)
 
 # Check for glibc backtrace functions
 AC_CHECK_FUNCS(backtrace backtrace_symbols)
diff --git a/libgfortran/intrinsics/ctime.c b/libgfortran/intrinsics/ctime.c
index b7b463c..932514e 100644
--- a/libgfortran/intrinsics/ctime.c
+++ b/libgfortran/intrinsics/ctime.c
@@ -25,42 +25,31 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
 #include "libgfortran.h"
 
-#ifdef TIME_WITH_SYS_TIME
-#  include <sys/time.h>
-#  include <time.h>
-#else
-#  if HAVE_SYS_TIME_H
-#    include <sys/time.h>
-#  else
-#    ifdef HAVE_TIME_H
-#      include <time.h>
-#    endif
-#  endif
-#endif
+#include "time_1.h"
 
 #include <string.h>
 
 
-#ifndef HAVE_CTIME_R
-/* Make sure we don't see here a macro.  */
-#undef ctime_r
+/* strftime-like function that fills a C string with %c format which
+   is identical to ctime in the default locale. As ctime and ctime_r
+   are poorly specified and their usage not recommended, the
+   implementation instead uses strftime.  */
 
-static char *
-ctime_r (const time_t * timep, char * buf __attribute__((unused)))
+static size_t
+strctime (char *s, size_t max, const time_t *timep)
 {
-#ifdef HAVE_CTIME
-  char *tmp = ctime (timep);
-  if (tmp)
-    tmp = strcpy (buf, tmp);
-  return tmp;
+#ifdef HAVE_STRFTIME
+  struct tm res;
+  struct tm *ltm = localtime_r (timep, &res);
+  return strftime (s, max, "%c", ltm);
 #else
-  return NULL;
+  return 0;
 #endif
 }
-#endif
 
-/* ctime_r() buffer size needs to be at least 26 bytes.  */
-#define CSZ 26
+/* In the default locale, the date and time representation fits in 26
+   bytes. However, other locales might need more space.  */
+#define CSZ 100
 
 extern void fdate (char **, gfc_charlen_type *);
 export_proto(fdate);
@@ -68,29 +57,15 @@ export_proto(fdate);
 void
 fdate (char ** date, gfc_charlen_type * date_len)
 {
-#if defined(HAVE_TIME) && defined(HAVE_CTIME)
-  char cbuf[CSZ];
-  int i;
+#if defined(HAVE_TIME)
   time_t now = time(NULL);
-  *date = ctime_r (&now, cbuf);
-  if (*date != NULL)
-    {
-      *date = strdup (*date);
-      *date_len = strlen (*date);
-
-      i = 0;
-      while ((*date)[i])
-       {
-         if ((*date)[i] == '\n')
-           (*date)[i] = ' ';
-         i++;
-       }
-      return;
-    }
-#endif
+  *date = get_mem (CSZ);
+  *date_len = strctime (*date, CSZ, &now);
+#else
 
   *date = NULL;
   *date_len = 0;
+#endif
 }
 
 
@@ -100,22 +75,14 @@ export_proto(fdate_sub);
 void
 fdate_sub (char * date, gfc_charlen_type date_len)
 {
-#if defined(HAVE_TIME) && defined(HAVE_CTIME)
-  char cbuf[CSZ];
-  int i;
-  char *d;
+#if defined(HAVE_TIME)
   time_t now = time(NULL);
-#endif
-  
+  char *s = get_mem (date_len + 1);
+  size_t n = strctime (s, date_len + 1, &now);
+  fstrcpy (date, date_len, s, n);
+  free (s);
+#else
   memset (date, ' ', date_len);
-#if defined(HAVE_TIME) && defined(HAVE_CTIME)
-  d = ctime_r (&now, cbuf);
-  if (d != NULL)
-    {
-      i = 0;
-      while (*d && *d != '\n' && i < date_len)
-       date[i++] = *(d++);
-    }
 #endif
 }
 
@@ -127,29 +94,15 @@ export_proto_np(PREFIX(ctime));
 void
 PREFIX(ctime) (char ** date, gfc_charlen_type * date_len, GFC_INTEGER_8 t)
 {
-#if defined(HAVE_CTIME)
-  char cbuf[CSZ];
+#if defined(HAVE_TIME)
   time_t now = t;
-  int i;
-  *date = ctime_r (&now, cbuf);
-  if (*date != NULL)
-    {
-      *date = strdup (*date);
-      *date_len = strlen (*date);
-
-      i = 0;
-      while ((*date)[i])
-       {
-         if ((*date)[i] == '\n')
-           (*date)[i] = ' ';
-         i++;
-       }
-      return;
-    }
-#endif
+  *date = get_mem (CSZ);
+  *date_len = strctime (*date, CSZ, &now);
+#else
 
   *date = NULL;
   *date_len = 0;
+#endif
 }
 
 
@@ -159,21 +112,8 @@ export_proto(ctime_sub);
 void
 ctime_sub (GFC_INTEGER_8 * t, char * date, gfc_charlen_type date_len)
 {
-#if defined(HAVE_CTIME)
-  char cbuf[CSZ];
-  int i;
-  char *d;
   time_t now = *t;
-#endif
-  
-  memset (date, ' ', date_len);
-#if defined(HAVE_CTIME)
-  d = ctime_r (&now, cbuf);
-  if (d != NULL)
-    {
-      i = 0;
-      while (*d && *d != '\n' && i < date_len)
-       date[i++] = *(d++);
-    }
-#endif
+  char *s = get_mem (date_len + 1);
+  size_t n = strctime (s, date_len + 1, &now);
+  fstrcpy (date, date_len, s, n);
 }
diff --git a/libgfortran/intrinsics/date_and_time.c b/libgfortran/intrinsics/date_and_time.c
index c58d114..793df68 100644
--- a/libgfortran/intrinsics/date_and_time.c
+++ b/libgfortran/intrinsics/date_and_time.c
@@ -36,24 +36,10 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #endif
 
 
-/* If the re-entrant versions of localtime and gmtime are not
-   available, provide fallback implementations.  On some targets where
-   the _r versions are not available, localtime and gmtime use
-   thread-local storage so they are threadsafe.  */
-
-#ifndef HAVE_LOCALTIME_R
-/* If _POSIX is defined localtime_r gets defined by mingw-w64 headers.  */
-#ifdef localtime_r
-#undef localtime_r
-#endif
-
-static struct tm *
-localtime_r (const time_t * timep, struct tm * result)
-{
-  *result = *localtime (timep);
-  return result;
-}
-#endif
+/* If the re-entrant version of gmtime is not available, provide a
+   fallback implementation.  On some targets where the _r version is
+   not available, gmtime uses thread-local storage so it's
+   threadsafe.  */
 
 #ifndef HAVE_GMTIME_R
 /* If _POSIX is defined gmtime_r gets defined by mingw-w64 headers.  */
diff --git a/libgfortran/intrinsics/time_1.h b/libgfortran/intrinsics/time_1.h
index 073595a..12d79eb 100644
--- a/libgfortran/intrinsics/time_1.h
+++ b/libgfortran/intrinsics/time_1.h
@@ -84,6 +84,26 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #endif  /* !HAVE_GETRUSAGE || !HAVE_SYS_RESOURCE_H  */
 
 
+/* If the re-entrant version of localtime is not available, provide a
+   fallback implementation.  On some targets where the _r version is
+   not available, localtime uses thread-local storage so it's
+   threadsafe.  */
+
+#ifndef HAVE_LOCALTIME_R
+/* If _POSIX is defined localtime_r gets defined by mingw-w64 headers.  */
+#ifdef localtime_r
+#undef localtime_r
+#endif
+
+static inline struct tm *
+localtime_r (const time_t * timep, struct tm * result)
+{
+  *result = *localtime (timep);
+  return result;
+}
+#endif
+
+
 #if defined (__GNUC__) && (__GNUC__ >= 3)
 #  define ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
 #else