diff options
Diffstat (limited to 'time')
| -rw-r--r-- | time/tzfile.c | 107 |
1 files changed, 81 insertions, 26 deletions
diff --git a/time/tzfile.c b/time/tzfile.c index 841f598c87..8ee48960f1 100644 --- a/time/tzfile.c +++ b/time/tzfile.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc. +/* Copyright (C) 1991, 1992, 1993, 1995 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -26,12 +26,6 @@ Cambridge, MA 02139, USA. */ #define NOID #include <tzfile.h> -#ifndef HAVE_GNU_LD -#define __tzname tzname -#define __daylight daylight -#define __timezone timezone -#endif - int __use_tzfile = 0; struct ttinfo @@ -39,7 +33,8 @@ struct ttinfo long int offset; /* Seconds east of GMT. */ unsigned char isdst; /* Used to set tm_isdst. */ unsigned char idx; /* Index into `zone_names'. */ - unsigned char isstd; /* Transition times are standard time. */ + unsigned char isstd; /* Transition times are in standard time. */ + unsigned char isgmt; /* Transition times are in GMT. */ }; struct leap @@ -67,7 +62,7 @@ static struct leap *leaps = NULL; void DEFUN(__tzfile_read, (file), CONST char *file) { - size_t num_isstd; + size_t num_isstd, num_isgmt; register FILE *f; struct tzhead tzhead; size_t chars; @@ -113,10 +108,11 @@ DEFUN(__tzfile_read, (file), CONST char *file) goto lose; num_transitions = (size_t) uc2ul(tzhead.tzh_timecnt); - num_types = (size_t) uc2ul(tzhead.tzh_typecnt); - chars = (size_t) uc2ul(tzhead.tzh_charcnt); - num_leaps = (size_t) uc2ul(tzhead.tzh_leapcnt); - num_isstd = (size_t) uc2ul(tzhead.tzh_ttisstdcnt); + num_types = (size_t) uc2ul (tzhead.tzh_typecnt); + chars = (size_t) uc2ul (tzhead.tzh_charcnt); + num_leaps = (size_t) uc2ul (tzhead.tzh_leapcnt); + num_isstd = (size_t) uc2ul (tzhead.tzh_ttisstdcnt); + num_isgmt = (size_t) uc2ul (tzhead.tzh_ttisgmtcnt); if (num_transitions > 0) { @@ -188,6 +184,16 @@ DEFUN(__tzfile_read, (file), CONST char *file) while (i < num_types) types[i++].isstd = 0; + for (i = 0; i < num_isgmt; ++i) + { + char c = getc(f); + if (c == EOF) + goto lose; + types[i].isgmt = c != 0; + } + while (i < num_types) + types[i++].isgmt = 0; + (void) fclose(f); compute_tzname_max (chars); @@ -199,12 +205,18 @@ DEFUN(__tzfile_read, (file), CONST char *file) (void) fclose(f); } +/* The user specified a hand-made timezone, but not its DST rules. + We will use the names and offsets from the user, and the rules + from the TZDEFRULES file. */ + void DEFUN(__tzfile_default, (std, dst, stdoff, dstoff), char *std AND char *dst AND long int stdoff AND long int dstoff) { size_t stdlen, dstlen, i; + long int rule_offset, rule_stdoff, rule_dstoff; + int isdst; __tzfile_read (TZDEFRULES); if (!__use_tzfile) @@ -216,8 +228,10 @@ DEFUN(__tzfile_default, (std, dst, stdoff, dstoff), return; } + /* Ignore the zone names read from the file. */ free (zone_names); + /* Use the names the user specified. */ stdlen = strlen (std) + 1; dstlen = strlen (dst) + 1; zone_names = malloc (stdlen + dstlen); @@ -229,19 +243,60 @@ DEFUN(__tzfile_default, (std, dst, stdoff, dstoff), memcpy (zone_names, std, stdlen); memcpy (&zone_names[stdlen], dst, dstlen); - for (i = 0; i < num_types; ++i) - if (types[i].isdst) - { - types[i].idx = stdlen; - if (dst[0] != '\0') - types[i].offset = dstoff; - } - else - { - types[i].idx = 0; - if (dst[0] != '\0') - types[i].offset = stdoff; - } + /* Find the standard and daylight time offsets used by the rule file. + We choose the offsets in the types of each flavor that are + transitioned to earliest in time. */ + rule_dstoff = 0; + for (i = 0; i < num_transitions; ++i) + { + if (!rule_stdoff && !types[type_idxs[i]].isdst) + rule_stdoff = types[type_idxs[i]].offset; + if (!rule_dstoff && types[type_idxs[i]].isdst) + rule_dstoff = types[type_idxs[i]].offset; + if (rule_stdoff && rule_dstoff) + break; + } + + /* Now correct the transition times for the user-specified standard and + daylight offsets from GMT. */ + isdst = 0; + rule_offset = rule_offset; + for (i = 0; i < num_transitions; ++i) + { + struct ttinfo *trans_type = &types[type_idxs[i]]; + + /* We will use only types 0 (standard) and 1 (daylight). + Fix up this transition to point to whichever matches + the flavor of its original type. */ + type_idxs[i] = trans_type->isdst; + + if (trans_type->isgmt) + /* The transition time is in GMT. No correction to apply. */ ; + else if (isdst && !trans_type->isstd) + /* The type says this transition is in "local wall clock time", and + wall clock time as of the previous transition was DST. Correct + for the difference between the rule's DST offset and the user's + DST offset. */ + transitions[i] += dstoff - rule_dstoff; + else + /* This transition is in "local wall clock time", and wall clock + time as of this iteration is non-DST. Correct for the + difference between the rule's standard offset and the user's + standard offset. */ + transitions[i] += stdoff - rule_stdoff; + + /* The DST state of "local wall clock time" for the next iteration is + as specified by this transition. */ + isdst = trans_type->isdst; + } + + /* Reset types 0 and 1 to describe the user's settings. */ + types[0].idx = 0; + types[0].offset = stdoff; + types[0].isdst = 0; + types[1].idx = stdlen; + types[1].offset = dstoff; + types[1].isdst = 1; compute_tzname_max (stdlen + dstlen); } |