libgfortran/intrinsics/ctime.c

   1 /* Implementation of the CTIME and FDATE g77 intrinsics.
   2    Copyright (C) 2005-2018 Free Software Foundation, Inc.
   3    Contributed by François-Xavier Coudert <coudert@clipper.ens.fr>
   4
   5 This file is part of the GNU Fortran runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU General Public
   9 License as published by the Free Software Foundation; either
  10 version 3 of the License, or (at your option) any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgfortran.h"
  27
  28 #include "time_1.h"
  29
  30 #include <string.h>
  31
  32
  33 /* Maximum space a ctime-like string might need. A "normal" ctime
  34    string is 26 bytes, and in our case 24 bytes as we don't include
  35    the trailing newline and null. However, the longest possible year
  36    number is -2,147,481,748 (1900 - 2,147,483,648, since tm_year is a
  37    32-bit signed integer) so an extra 7 bytes are needed. */
  38 #define CTIME_BUFSZ 31
  39
  40
  41 /* Thread-safe ctime-like function that fills a Fortran
  42    string. ctime_r is a portability headache and marked as obsolescent
  43    in POSIX 2008, which recommends strftime in its place. However,
  44    strftime(..., "%c",...)  doesn't produce ctime-like output on
  45    MinGW, so do it manually with snprintf.  */
  46
  47 static int
  48 gf_ctime (char *s, size_t max, const time_t timev)
  49 {
  50   struct tm ltm;
  51   int failed;
  52   char buf[CTIME_BUFSZ + 1];
  53   /* Some targets provide a localtime_r based on a draft of the POSIX
  54      standard where the return type is int rather than the
  55      standardized struct tm*.  */
  56   __builtin_choose_expr (__builtin_classify_type (localtime_r (&timev, &ltm))
  57                          == 5,
  58                          failed = localtime_r (&timev, &ltm) == NULL,
  59                          failed = localtime_r (&timev, &ltm) != 0);
  60   if (failed)
  61     goto blank;
  62   int n = snprintf (buf, sizeof (buf),
  63                     "%3.3s %3.3s%3d %.2d:%.2d:%.2d %d",
  64                     "SunMonTueWedThuFriSat" + ltm.tm_wday * 3,
  65                     "JanFebMarAprMayJunJulAugSepOctNovDec" + ltm.tm_mon * 3,
  66                     ltm.tm_mday, ltm.tm_hour, ltm.tm_min, ltm.tm_sec,
  67                     1900 + ltm.tm_year);
  68   if (n < 0)
  69     goto blank;
  70   if ((size_t) n <= max)
  71     {
  72       cf_strcpy (s, max, buf);
  73       return n;
  74     }
  75  blank:
  76   memset (s, ' ', max);
  77   return 0;
  78 }
  79
  80
  81 extern void fdate (char **, gfc_charlen_type *);
  82 export_proto(fdate);
  83
  84 void
  85 fdate (char ** date, gfc_charlen_type * date_len)
  86 {
  87   time_t now = time(NULL);
  88   *date = xmalloc (CTIME_BUFSZ);
  89   *date_len = gf_ctime (*date, CTIME_BUFSZ, now);
  90 }
  91
  92
  93 extern void fdate_sub (char *, gfc_charlen_type);
  94 export_proto(fdate_sub);
  95
  96 void
  97 fdate_sub (char * date, gfc_charlen_type date_len)
  98 {
  99   time_t now = time(NULL);
 100   gf_ctime (date, date_len, now);
 101 }
 102
 103
 104
 105 extern void PREFIX(ctime) (char **, gfc_charlen_type *, GFC_INTEGER_8);
 106 export_proto_np(PREFIX(ctime));
 107
 108 void
 109 PREFIX(ctime) (char ** date, gfc_charlen_type * date_len, GFC_INTEGER_8 t)
 110 {
 111   time_t now = t;
 112   *date = xmalloc (CTIME_BUFSZ);
 113   *date_len = gf_ctime (*date, CTIME_BUFSZ, now);
 114 }
 115
 116
 117 extern void ctime_sub (GFC_INTEGER_8 *, char *, gfc_charlen_type);
 118 export_proto(ctime_sub);
 119
 120 void
 121 ctime_sub (GFC_INTEGER_8 * t, char * date, gfc_charlen_type date_len)
 122 {
 123   time_t now = *t;
 124   gf_ctime (date, date_len, now);
 125 }