usr/src/lib/libast/common/tm/tmgoff.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * Glenn Fowler
  25  * AT&T Bell Laboratories
  26  *
  27  * time conversion support
  28  */
  29
  30 #include <ast.h>
  31 #include <tm.h>
  32 #include <ctype.h>
  33
  34 /*
  35  * return minutes offset from absolute timezone expression
  36  *
  37  *      [[-+]hh[:mm[:ss]]]
  38  *      [-+]hhmm
  39  *
  40  * if e is non-null then it points to the first unrecognized char in s
  41  * d returned if no offset in s
  42  */
  43
  44 int
  45 tmgoff(register const char* s, char** e, int d)
  46 {
  47         register int    n = d;
  48         int             east;
  49         const char*     t = s;
  50
  51         if ((east = *s == '+') || *s == '-')
  52         {
  53                 s++;
  54                 if (isdigit(*s) && isdigit(*(s + 1)))
  55                 {
  56                         n = ((*s - '0') * 10 + (*(s + 1) - '0')) * 60;
  57                         s += 2;
  58                         if (*s == ':')
  59                                 s++;
  60                         if (isdigit(*s) && isdigit(*(s + 1)))
  61                         {
  62                                 n += ((*s - '0') * 10 + (*(s + 1) - '0'));
  63                                 s += 2;
  64                                 if (*s == ':')
  65                                         s++;
  66                                 if (isdigit(*s) && isdigit(*(s + 1)))
  67                                         s += 2;
  68                         }
  69                         if (east)
  70                                 n = -n;
  71                         t = s;
  72                 }
  73         }
  74         if (e)
  75                 *e = (char*)t;
  76         return n;
  77 }