437 lines
11 KiB
C
437 lines
11 KiB
C
/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <localeinfo.h>
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#include <ctype.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#ifndef HAVE_GNU_LD
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#define __tzname tzname
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#define __daylight daylight
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#define __timezone timezone
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#endif
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extern int __use_tzfile;
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extern void EXFUN(__tzfile_read, (CONST char *file));
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extern int EXFUN(__tzfile_compute, (time_t, struct tm));
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char *__tzname[2] = { (char *) "GMT", (char *) "GMT" };
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int __daylight = 0;
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long int __timezone = 0L;
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#define min(a, b) ((a) < (b) ? (a) : (b))
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#define max(a, b) ((a) > (b) ? (a) : (b))
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#define sign(x) ((x) < 0 ? -1 : 1)
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/* This structure contains all the information about a
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timezone given in the POSIX standard TZ envariable. */
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typedef struct
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{
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CONST char *name;
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/* When to change. */
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enum { J0, J1, M } type; /* Interpretation of: */
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unsigned short int m, n, d; /* Month, week, day. */
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unsigned int secs:17; /* Time of day. */
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long int offset; /* Seconds east of GMT (west if < 0). */
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/* We cache the computed time of change for a
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given year so we don't have to recompute it. */
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time_t change; /* When to change to this zone. */
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int computed_for; /* Year above is computed for. */
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} tz_rule;
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/* tz_rules[0] is standard, tz_rules[1] is daylight. */
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static tz_rule tz_rules[2];
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static int tzset_run = 0;
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/* Interpret the TZ envariable. */
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void
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DEFUN_VOID(__tzset)
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{
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register CONST char *tz;
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register size_t l;
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unsigned short int hh, mm, ss;
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unsigned short int whichrule;
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/* Free old storage. */
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if (tz_rules[0].name != NULL && *tz_rules[0].name != '\0')
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free((PTR) tz_rules[0].name);
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if (tz_rules[1].name != NULL && *tz_rules[1].name != '\0' &&
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tz_rules[1].name != tz_rules[0].name)
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free((PTR) tz_rules[1].name);
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tz = getenv("TZ");
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if (tz != NULL && *tz == ':')
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{
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__tzfile_read(tz + 1);
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if (__use_tzfile)
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{
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tzset_run = 1;
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return;
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}
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else
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tz = NULL;
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}
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if (tz == NULL || *tz == '\0')
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tz = _time_info->tz;
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if (tz == NULL || *tz == '\0')
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{
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__tzfile_read((char *) NULL);
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if (!__use_tzfile)
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{
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size_t len = strlen(_time_info->ut0) + 1;
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tz_rules[0].name = (char *) malloc(len);
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if (tz_rules[0].name == NULL)
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return;
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tz_rules[1].name = (char *) malloc(len);
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if (tz_rules[1].name == NULL)
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return;
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memcpy((PTR) tz_rules[0].name, _time_info->ut0, len);
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memcpy((PTR) tz_rules[1].name, _time_info->ut0, len);
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tz_rules[0].type = tz_rules[1].type = J0;
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tz_rules[0].m = tz_rules[0].n = tz_rules[0].d = 0;
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tz_rules[1].m = tz_rules[1].n = tz_rules[1].d = 0;
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tz_rules[0].secs = tz_rules[1].secs = 0;
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tz_rules[0].offset = tz_rules[1].offset = 0L;
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tz_rules[0].change = tz_rules[1].change = (time_t) -1;
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tz_rules[0].computed_for = tz_rules[1].computed_for = 0;
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}
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tzset_run = 1;
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return;
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}
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/* Get the standard timezone name. */
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tz_rules[0].name = (char *) malloc(strlen(tz) + 1);
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if (tz_rules[0].name == NULL)
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return;
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if (sscanf(tz, "%[^0-9,+-]", tz_rules[0].name) != 1 ||
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(l = strlen(tz_rules[0].name)) < 3)
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return;
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tz_rules[0].name = (char *) realloc((PTR) tz_rules[0].name, l + 1);
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if (tz_rules[0].name == NULL)
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return;
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tz += l;
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/* Figure out the standard offset from GMT. */
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if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit(*tz)))
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return;
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if (*tz == '-' || *tz == '+')
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tz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
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else
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tz_rules[0].offset = -1L;
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switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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return;
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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break;
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}
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tz_rules[0].offset *= (min(ss, 59) + (min(mm, 59) * 60) +
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(min(hh, 12) * 60 * 60));
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for (l = 0; l < 3; ++l)
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{
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while (isdigit(*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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/* Get the DST timezone name (if any). */
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if (*tz == '\0')
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tz_rules[1].name = "";
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else
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{
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tz_rules[1].name = (char *) malloc(strlen(tz) + 1);
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if (tz_rules[1].name == NULL)
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return;
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if (sscanf(tz, "%[^0-9,+-]", tz_rules[1].name) != 1 ||
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(l = strlen(tz_rules[1].name)) < 3)
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return;
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tz_rules[1].name = (char *) realloc((PTR) tz_rules[1].name, l + 1);
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if (tz_rules[1].name == NULL)
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return;
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}
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tz += l;
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/* Figure out the DST offset from GMT. */
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if (*tz == '-' || *tz == '+')
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tz_rules[1].offset = *tz++ == '-' ? 1L : -1L;
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else
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tz_rules[1].offset = -1L;
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switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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/* Default to one hour later than standard time. */
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tz_rules[1].offset *= abs (tz_rules[0].offset);
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hh = 1;
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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break;
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}
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tz_rules[1].offset *= (min(ss, 59) + (min(mm, 59) * 60) +
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(min(hh, 12) * (60 * 60)));
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for (l = 0; l < 3; ++l)
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{
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while (isdigit(*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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/* If no standard or DST offset was given, default to GMT
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for standard and one hour later than standard for DST. */
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if (*tz_rules[0].name == '\0')
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tz_rules[0].offset = 0L;
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if (*tz_rules[1].name == '\0')
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tz_rules[1].offset = tz_rules[0].offset + (60 * 60);
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if (*tz == '\0' || tz[0] == ',' && tz[1] == '\0')
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{
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/* There is no rule. See if there is a default rule file. */
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__tzfile_default (tz_rules[0].name, tz_rules[1].name,
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tz_rules[0].offset, tz_rules[1].offset);
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if (__use_tzfile)
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return;
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}
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/* Figure out the standard <-> DST rules. */
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for (whichrule = 0; whichrule < 2; ++whichrule)
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{
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register tz_rule *tzr = &tz_rules[whichrule];
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if (*tz != '\0' && *tz == ',')
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{
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++tz;
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if (*tz == '\0')
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return;
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}
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/* Get the date of the change. */
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if (*tz == 'J' || isdigit(*tz))
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{
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char *end;
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tzr->type = *tz == 'J' ? J1 : J0;
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if (tzr->type == J1 && !isdigit(*++tz))
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return;
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tzr->n = (unsigned short int) strtoul(tz, &end, 10);
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if (end == tz || tzr->n > 365)
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return;
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else if (tzr->type == J1 && tzr->n == 0)
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return;
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if (tzr->type == J1 && tzr->n == 60)
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/* Can't do February 29. */
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++tzr->n;
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tz = end;
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}
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else if (*tz == 'M')
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{
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int n;
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tzr->type = M;
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if (sscanf (tz, "M%hu.%hu.%hu%n",
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&tzr->m, &tzr->n, &tzr->d, &n) != 3 ||
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tzr->m < 1 || tzr->m > 12 ||
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tzr->n < 1 || tzr->n > 5 || tzr->d > 6)
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return;
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tz += n;
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}
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else if (*tz == '\0')
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{
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/* United States Federal Law, the equivalent of "M3.1.0,M8.5.0". */
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tzr->type = M;
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if (tzr == &tz_rules[0])
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{
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tzr->m = 4;
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tzr->n = 1;
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tzr->d = 0;
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}
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else
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{
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tzr->m = 10;
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tzr->n = 5;
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tzr->d = 0;
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}
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}
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else
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return;
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if (*tz != '\0' && *tz != '/' && *tz != ',')
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return;
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else if (*tz == '/')
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{
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/* Get the time of day of the change. */
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++tz;
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if (*tz == '\0')
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return;
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switch (sscanf(tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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return;
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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break;
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}
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for (l = 0; l < 3; ++l)
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{
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while (isdigit(*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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tzr->secs = (hh * 60 * 60) + (mm * 60) + ss;
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}
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else
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/* Default to 2:00 AM. */
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tzr->secs = 2 * 60 * 60;
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tzr->computed_for = -1;
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}
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tzset_run = 1;
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}
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/* Figure out the exact time (as a time_t) in YEAR
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when the change described by RULE will occur and
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put it in RULE->change, saving YEAR in RULE->computed_for.
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Return nonzero if successful, zero on failure. */
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static int
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DEFUN(compute_change, (rule, year), tz_rule *rule AND int year)
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{
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register unsigned short int m = rule->m, n = rule->n, d = rule->d;
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struct tm tbuf;
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register time_t t;
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if (year != -1 && rule->computed_for == year)
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/* Operations on times in 1969 will be slower. Oh well. */
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return 1;
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memset((PTR) &tbuf, 0, sizeof(tbuf));
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tbuf.tm_year = year;
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if (rule->type == M)
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{
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/* Defined in _offtime.c. */
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extern CONST unsigned short int __mon_lengths[2][12];
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unsigned short int ml = __mon_lengths[__isleap(tbuf.tm_year)][m - 1];
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tbuf.tm_mon = m - 1;
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if (n == 5)
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tbuf.tm_mday = ml;
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else
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tbuf.tm_mday = max((n - 1) * 7, 1);
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tbuf.tm_sec = rule->secs;
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t = mktime(&tbuf);
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if (t == (time_t) -1)
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return 0;
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if (tbuf.tm_wday != d)
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{
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if (d > tbuf.tm_wday)
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{
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tbuf.tm_mday -= 7;
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tbuf.tm_mday += tbuf.tm_wday - d;
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}
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else
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tbuf.tm_mday -= tbuf.tm_wday - d;
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if (tbuf.tm_mday < 1)
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tbuf.tm_mday += 7;
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else
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if (tbuf.tm_mday > ml) tbuf.tm_mday -= 7;
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t = mktime(&tbuf);
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if (t == (time_t) -1)
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return 0;
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}
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}
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else
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{
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tbuf.tm_mon = 0;
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if (rule->type == J1)
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--n;
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tbuf.tm_mday = n;
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tbuf.tm_sec = rule->secs;
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t = mktime(&tbuf);
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if (t == (time_t) -1)
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return 0;
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}
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rule->change = t;
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rule->computed_for = year;
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return 1;
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}
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/* Figure out the correct timezone for *TIMER and TM (which must be the same)
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and set `__tzname', `__timezone', and `__daylight' accordingly.
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Return nonzero on success, zero on failure. */
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int
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DEFUN(__tz_compute, (timer, tm),
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time_t timer AND struct tm tm)
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{
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if (!tzset_run)
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__tzset();
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if (__use_tzfile)
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return __tzfile_compute(timer, tm);
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if (!compute_change(&tz_rules[0], tm.tm_year) ||
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!compute_change(&tz_rules[1], tm.tm_year))
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return 0;
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__daylight = timer >= tz_rules[0].change && timer < tz_rules[1].change;
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__timezone = tz_rules[__daylight ? 1 : 0].offset;
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__tzname[0] = (char *) tz_rules[0].name;
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__tzname[1] = (char *) tz_rules[1].name;
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return 1;
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}
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long int
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DEFUN_VOID (__tzname_max)
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{
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size_t len0 = strlen (__tzname[0]), len1 = strlen (__tzname[1]);
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return len0 > len1 ? len0 : len1;
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}
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