lib/posixtm.c

   1 /* Parse dates for touch and date.
   2    Copyright (C) 1989, 1990, 1991, 1998, 2000 Free Software Foundation Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Yacc-based version written by Jim Kingdon and David MacKenzie.
  19    Rewritten by Jim Meyering.  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #include <stdio.h>
  26 #if HAVE_STDLIB_H
  27 # include <stdlib.h>
  28 #endif
  29 #include <sys/types.h>
  30 #if HAVE_STRING_H
  31 # include <string.h>
  32 #else
  33 # include <strings.h>
  34 #endif
  35
  36 #ifdef TM_IN_SYS_TIME
  37 # include <sys/time.h>
  38 #else
  39 # include <time.h>
  40 #endif
  41
  42 #include "posixtm.h"
  43
  44 /* ISDIGIT differs from isdigit, as follows:
  45    - Its arg may be any int or unsigned int; it need not be an unsigned char.
  46    - It's guaranteed to evaluate its argument exactly once.
  47    - It's typically faster.
  48    Posix 1003.2-1992 section 2.5.2.1 page 50 lines 1556-1558 says that
  49    only '0' through '9' are digits.  Prefer ISDIGIT to isdigit unless
  50    it's important to use the locale's definition of `digit' even when the
  51    host does not conform to Posix.  */
  52 #define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)
  53
  54 /* The return value. */
  55 static struct tm t;
  56
  57 time_t mktime ();
  58
  59 /*
  60   POSIX requires:
  61
  62   touch -t [[CC]YY]mmddhhmm[.ss] FILE...
  63     8, 10, or 12 digits, followed by optional .ss
  64     (PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS)
  65
  66   touch mmddhhmm[YY] FILE... (obsolescent)
  67     8 or 10 digits
  68     (PDS_TRAILING_YEAR)
  69
  70   date mmddhhmm[[CC]YY]
  71     8, 10, or 12 digits
  72     (PDS_TRAILING_YEAR | PDS_CENTURY)
  73
  74 */
  75
  76 static int
  77 year (const int *digit_pair, size_t n, int allow_century)
  78 {
  79   switch (n)
  80     {
  81     case 1:
  82       t.tm_year = *digit_pair;
  83       /* Deduce the century based on the year.
  84          See POSIX.2 section 4.63.3.  */
  85       if (digit_pair[0] <= 68)
  86         t.tm_year += 100;
  87       break;
  88
  89     case 2:
  90       if (!allow_century)
  91         return 1;
  92       t.tm_year = digit_pair[0] * 100 + digit_pair[1];
  93       if (t.tm_year < 1900)
  94         return 1;
  95       t.tm_year -= 1900;
  96       break;
  97
  98     case 0:
  99       {
 100         time_t now;
 101         struct tm *tmp;
 102
 103         /* Use current year.  */
 104         time (&now);
 105         tmp = localtime (&now);
 106         t.tm_year = tmp->tm_year;
 107       }
 108       break;
 109
 110     default:
 111       abort ();
 112     }
 113
 114   return 0;
 115 }
 116
 117 static int
 118 posix_time_parse (const char *s, unsigned int syntax_bits)
 119 {
 120   const char *dot = NULL;
 121   int pair[6];
 122   int *p;
 123   unsigned int i;
 124
 125   size_t s_len = strlen (s);
 126   size_t len = (((syntax_bits & PDS_SECONDS) && (dot = strchr (s, '.')))
 127                 ? dot - s
 128                 : s_len);
 129
 130   if (len != 8 && len != 10 && len != 12)
 131     return 1;
 132
 133   if (dot)
 134     {
 135       if (!(syntax_bits & PDS_SECONDS))
 136         return 1;
 137
 138       if (s_len - len != 3)
 139         return 1;
 140     }
 141
 142   for (i = 0; i < len; i++)
 143     if (!ISDIGIT (s[i]))
 144       return 1;
 145
 146   len /= 2;
 147   for (i = 0; i < len; i++)
 148     pair[i] = 10 * (s[2*i] - '0') + s[2*i + 1] - '0';
 149
 150   p = pair;
 151   if (syntax_bits & PDS_LEADING_YEAR)
 152     {
 153       if (year (p, len - 4, syntax_bits & PDS_CENTURY))
 154         return 1;
 155       p += len - 4;
 156       len = 4;
 157     }
 158
 159   /* Handle 8 digits worth of `MMDDhhmm'.  */
 160   if (*p < 1 || *p > 12)
 161     return 1;
 162   t.tm_mon = *p - 1;
 163   ++p; --len;
 164
 165   if (*p < 1 || *p > 31)
 166     return 1;
 167   t.tm_mday = *p;
 168   ++p; --len;
 169
 170   if (*p < 0 || *p > 23)
 171     return 1;
 172   t.tm_hour = *p;
 173   ++p; --len;
 174
 175   if (*p < 0 || *p > 59)
 176     return 1;
 177   t.tm_min = *p;
 178   ++p; --len;
 179
 180   /* Handle any trailing year.  */
 181   if (syntax_bits & PDS_TRAILING_YEAR)
 182     {
 183       if (year (p, len, syntax_bits & PDS_CENTURY))
 184         return 1;
 185     }
 186
 187   /* Handle seconds.  */
 188   if (!dot)
 189     {
 190       t.tm_sec = 0;
 191     }
 192   else
 193     {
 194       int seconds;
 195
 196       ++dot;
 197       if (!ISDIGIT (dot[0]) || !ISDIGIT (dot[1]))
 198         return 1;
 199       seconds = 10 * (dot[0] - '0') + dot[1] - '0';
 200
 201       if (seconds < 0 || seconds > 61)
 202         return 1;
 203       t.tm_sec = seconds;
 204     }
 205
 206   return 0;
 207 }
 208
 209 /* Parse a POSIX-style date and return it, or (time_t)-1 for an error.  */
 210
 211 time_t
 212 posixtime (const char *s, unsigned int syntax_bits)
 213 {
 214   t.tm_isdst = -1;
 215   if (posix_time_parse (s, syntax_bits))
 216     return (time_t)-1;
 217   else
 218     return mktime (&t);
 219 }
 220
 221 /* Parse a POSIX-style date and return it, or NULL for an error.  */
 222
 223 struct tm *
 224 posixtm (const char *s, unsigned int syntax_bits)
 225 {
 226   if (posixtime (s, syntax_bits) == -1)
 227     return NULL;
 228   return &t;
 229 }
 230
 231 #ifdef TEST_POSIXTIME
 232 /*
 233     Test mainly with syntax_bits == 13
 234     (aka: (PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS))
 235
 236 BEGIN-DATA
 237 1112131415      13 1323807300 Tue Dec 13 14:15:00 2011
 238 1112131415.16   13 1323807316 Tue Dec 13 14:15:16 2011
 239 201112131415.16 13 1323807316 Tue Dec 13 14:15:16 2011
 240 191112131415.16 13 -1 ***
 241 203712131415.16 13 2144348116 Sun Dec 13 14:15:16 2037
 242 3712131415.16   13 2144348116 Sun Dec 13 14:15:16 2037
 243 6812131415.16   13 -1 ***
 244 6912131415.16   13 -1 ***
 245 7012131415.16   13 29967316 Sun Dec 13 14:15:16 1970
 246 12131415.16     13 913580116 Sun Dec 13 14:15:16 1998
 247
 248 1213141599       2 945116100 Mon Dec 13 14:15:00 1999
 249 1213141500       2 976738500 Wed Dec 13 14:15:00 2000
 250 END-DATA
 251
 252 */
 253
 254 # define MAX_BUFF_LEN 1024
 255
 256 int
 257 main ()
 258 {
 259   char buff[MAX_BUFF_LEN + 1];
 260
 261   buff[MAX_BUFF_LEN] = 0;
 262   while (fgets (buff, MAX_BUFF_LEN, stdin) && buff[0])
 263     {
 264       char time_str[MAX_BUFF_LEN];
 265       unsigned int syntax_bits;
 266       time_t t;
 267       char *result;
 268       sscanf (buff, "%s %u", time_str, &syntax_bits);
 269       t = posixtime (time_str, syntax_bits);
 270       result = (t == (time_t) -1 ? "***" : ctime (&t));
 271       printf ("%d %s\n", (int) t, result);
 272     }
 273   exit (0);
 274
 275 }
 276 #endif