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Diffstat (limited to 'lib/parse-date.y')
| -rw-r--r-- | lib/parse-date.y | 1626 |
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diff --git a/lib/parse-date.y b/lib/parse-date.y new file mode 100644 index 0000000..bb5abb5 --- /dev/null +++ b/lib/parse-date.y @@ -0,0 +1,1626 @@ +%{ +/** + * Parse a string into an internal timestamp. + * + * This file is based on gnulib parse-datetime.y-dd7a871 with + * the other gnulib dependencies removed for use in util-linux. + * + * Copyright (C) 1999-2000, 2002-2017 Free Software Foundation, Inc. + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Originally written by Steven M. Bellovin <smb@research.att.com> while + * at the University of North Carolina at Chapel Hill. Later tweaked by + * a couple of people on Usenet. Completely overhauled by Rich $alz + * <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990. + * + * Modified by Paul Eggert <eggert@twinsun.com> in August 1999 to do + * the right thing about local DST. Also modified by Paul Eggert + * <eggert@cs.ucla.edu> in February 2004 to support + * nanosecond-resolution timestamps, and in October 2004 to support + * TZ strings in dates. + */ + +/** + * FIXME: Check for arithmetic overflow in all cases, not just + * some of them. + */ + +#include <sys/time.h> +#include <time.h> + +#include "c.h" +#include "timeutils.h" + +/** + * There's no need to extend the stack, so there's no need to involve + * alloca. + */ +#define YYSTACK_USE_ALLOCA 0 + +/** + * Tell Bison how much stack space is needed. 20 should be plenty for + * this grammar, which is not right recursive. Beware setting it too + * high, since that might cause problems on machines whose + * implementations have lame stack-overflow checking. + */ +#define YYMAXDEPTH 20 +#define YYINITDEPTH YYMAXDEPTH + +/** + * Since the code of parse-datetime.y is not included in the Emacs executable + * itself, there is no need to #define static in this file. Even if + * the code were included in the Emacs executable, it probably + * wouldn't do any harm to #undef it here; this will only cause + * problems if we try to write to a static variable, which I don't + * think this code needs to do. + */ +#ifdef emacs +# undef static +#endif + +#include <inttypes.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + + +#include <stdarg.h> +#include "cctype.h" +#include "nls.h" + +/** + * Bison's skeleton tests _STDLIB_H, while some stdlib.h headers + * use _STDLIB_H_ as witness. Map the latter to the one bison uses. + * FIXME: this is temporary. Remove when we have a mechanism to ensure + * that the version we're using is fixed, too. + */ +#ifdef _STDLIB_H_ +# undef _STDLIB_H +# define _STDLIB_H 1 +#endif + +/** + * Shift A right by B bits portably, by dividing A by 2**B and + * truncating towards minus infinity. A and B should be free of side + * effects, and B should be in the range 0 <= B <= INT_BITS - 2, where + * INT_BITS is the number of useful bits in an int. GNU code can + * assume that INT_BITS is at least 32. + * + * ISO C99 says that A >> B is implementation-defined if A < 0. Some + * implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift + * right in the usual way when A < 0, so SHR falls back on division if + * ordinary A >> B doesn't seem to be the usual signed shift. + */ +#define SHR(a, b) \ + (-1 >> 1 == -1 \ + ? (a) >> (b) \ + : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0)) + +#define TM_YEAR_BASE 1900 + +#define HOUR(x) ((x) * 60) + +#define STREQ(a, b) (strcmp (a, b) == 0) + +/** + * Convert a possibly-signed character to an unsigned character. This is + * a bit safer than casting to unsigned char, since it catches some type + * errors that the cast doesn't. + */ +static unsigned char to_uchar (char ch) { return ch; } + +/** + * FIXME: It also assumes that signed integer overflow silently wraps around, + * but this is not true any more with recent versions of GCC 4. + */ + +/** + * An integer value, and the number of digits in its textual + * representation. + */ +typedef struct { + int negative; + intmax_t value; + size_t digits; +} textint; + +/* An entry in the lexical lookup table. */ +typedef struct { + char const *name; + int type; + int value; +} table; + +/* Meridian: am, pm, or 24-hour style. */ +enum { MERam, MERpm, MER24 }; + +enum { BILLION = 1000000000, LOG10_BILLION = 9 }; + +/* Relative year, month, day, hour, minutes, seconds, and nanoseconds. */ +typedef struct { + intmax_t year; + intmax_t month; + intmax_t day; + intmax_t hour; + intmax_t minutes; + time_t seconds; + int ns; +} relative_time; + +#if HAVE_COMPOUND_LITERALS +# define RELATIVE_TIME_0 ((relative_time) { 0, 0, 0, 0, 0, 0, 0 }) +#else +static relative_time const RELATIVE_TIME_0; +#endif + +/* Information passed to and from the parser. */ +typedef struct { + /* The input string remaining to be parsed. */ + const char *input; + + /* N, if this is the Nth Tuesday. */ + intmax_t day_ordinal; + + /* Day of week; Sunday is 0. */ + int day_number; + + /* tm_isdst flag for the local zone. */ + int local_isdst; + + /* Time zone, in minutes east of UTC. */ + int time_zone; + + /* Style used for time. */ + int meridian; + + /* Gregorian year, month, day, hour, minutes, seconds, and ns. */ + textint year; + intmax_t month; + intmax_t day; + intmax_t hour; + intmax_t minutes; + struct timespec seconds; /* includes nanoseconds */ + + /* Relative year, month, day, hour, minutes, seconds, and ns. */ + relative_time rel; + + /* Presence or counts of some nonterminals parsed so far. */ + int timespec_seen; + int rels_seen; + size_t dates_seen; + size_t days_seen; + size_t local_zones_seen; + size_t dsts_seen; + size_t times_seen; + size_t zones_seen; + + /* Table of local time zone abbreviations, null terminated. */ + table local_time_zone_table[3]; +} parser_control; + +union YYSTYPE; +static int yylex (union YYSTYPE *, parser_control *); +static int yyerror (parser_control const *, char const *); +static int time_zone_hhmm (parser_control *, textint, textint); + +/** + * Extract into *PC any date and time info from a string of digits + * of the form e.g., YYYYMMDD, YYMMDD, HHMM, HH (and sometimes YYY, + * YYYY, ...). + */ +static void digits_to_date_time(parser_control *pc, textint text_int) +{ + if (pc->dates_seen && ! pc->year.digits + && ! pc->rels_seen && (pc->times_seen || 2 < text_int.digits)) { + pc->year = text_int; + } else { + if (4 < text_int.digits) { + pc->dates_seen++; + pc->day = text_int.value % 100; + pc->month = (text_int.value / 100) % 100; + pc->year.value = text_int.value / 10000; + pc->year.digits = text_int.digits - 4; + } else { + pc->times_seen++; + if (text_int.digits <= 2) { + pc->hour = text_int.value; + pc->minutes = 0; + } + else { + pc->hour = text_int.value / 100; + pc->minutes = text_int.value % 100; + } + pc->seconds.tv_sec = 0; + pc->seconds.tv_nsec = 0; + pc->meridian = MER24; + } + } +} + +/* Increment PC->rel by FACTOR * REL (FACTOR is 1 or -1). */ +static void apply_relative_time(parser_control *pc, relative_time rel, + int factor) +{ + pc->rel.ns += factor * rel.ns; + pc->rel.seconds += factor * rel.seconds; + pc->rel.minutes += factor * rel.minutes; + pc->rel.hour += factor * rel.hour; + pc->rel.day += factor * rel.day; + pc->rel.month += factor * rel.month; + pc->rel.year += factor * rel.year; + pc->rels_seen = 1; +} + +/* Set PC-> hour, minutes, seconds and nanoseconds members from arguments. */ +static void +set_hhmmss(parser_control *pc, intmax_t hour, intmax_t minutes, + time_t sec, int nsec) +{ + pc->hour = hour; + pc->minutes = minutes; + pc->seconds.tv_sec = sec; + pc->seconds.tv_nsec = nsec; +} + +%} + +/** + * We want a reentrant parser, even if the TZ manipulation and the calls to + * localtime and gmtime are not reentrant. + */ +%pure-parser +%parse-param { parser_control *pc } +%lex-param { parser_control *pc } + +/* This grammar has 31 shift/reduce conflicts. */ +%expect 31 + +%union { + intmax_t intval; + textint textintval; + struct timespec timespec; + relative_time rel; +} + +%token <intval> tAGO +%token tDST + +%token tYEAR_UNIT tMONTH_UNIT tHOUR_UNIT tMINUTE_UNIT tSEC_UNIT +%token <intval> tDAY_UNIT tDAY_SHIFT + +%token <intval> tDAY tDAYZONE tLOCAL_ZONE tMERIDIAN +%token <intval> tMONTH tORDINAL tZONE + +%token <textintval> tSNUMBER tUNUMBER +%token <timespec> tSDECIMAL_NUMBER tUDECIMAL_NUMBER + +%type <textintval> o_colon_minutes +%type <timespec> seconds signed_seconds unsigned_seconds + +%type <rel> relunit relunit_snumber dayshift + +%% + +spec: + timespec + | items +; + +timespec: + '@' seconds { + pc->seconds = $2; + pc->timespec_seen = 1; + } +; + +items: + /* empty */ + | items item +; + +item: + datetime { + pc->times_seen++; pc->dates_seen++; + } + | time { + pc->times_seen++; + } + | local_zone { + pc->local_zones_seen++; + } + | zone { + pc->zones_seen++; + } + | date { + pc->dates_seen++; + } + | day { + pc->days_seen++; + } + | rel + | number + | hybrid +; + +datetime: + iso_8601_datetime +; + +iso_8601_datetime: + iso_8601_date 'T' iso_8601_time +; + +time: + tUNUMBER tMERIDIAN { + set_hhmmss (pc, $1.value, 0, 0, 0); + pc->meridian = $2; + } + | tUNUMBER ':' tUNUMBER tMERIDIAN { + set_hhmmss (pc, $1.value, $3.value, 0, 0); + pc->meridian = $4; + } + | tUNUMBER ':' tUNUMBER ':' unsigned_seconds tMERIDIAN { + set_hhmmss (pc, $1.value, $3.value, $5.tv_sec, $5.tv_nsec); + pc->meridian = $6; + } + | iso_8601_time +; + +iso_8601_time: + tUNUMBER zone_offset { + set_hhmmss (pc, $1.value, 0, 0, 0); + pc->meridian = MER24; + } + | tUNUMBER ':' tUNUMBER o_zone_offset { + set_hhmmss (pc, $1.value, $3.value, 0, 0); + pc->meridian = MER24; + } + | tUNUMBER ':' tUNUMBER ':' unsigned_seconds o_zone_offset { + set_hhmmss (pc, $1.value, $3.value, $5.tv_sec, $5.tv_nsec); + pc->meridian = MER24; + } +; + +o_zone_offset: + /* empty */ + | zone_offset +; + +zone_offset: + tSNUMBER o_colon_minutes { + pc->zones_seen++; + if (! time_zone_hhmm (pc, $1, $2)) YYABORT; + } +; + +/** + * Local zone strings only affect DST setting, + * and only take affect if the current TZ setting is relevant. + * + * Example 1: + * 'EEST' is parsed as tLOCAL_ZONE, as it relates to the effective TZ: + * TZ=Europe/Helsinki date -d '2016-12-30 EEST' + * + * Example 2: + * 'EEST' is parsed as 'zone' (TZ=+03:00): + * TZ=Asia/Tokyo ./src/date --debug -d '2011-06-11 EEST' + * + * This is implemented by probing the next three calendar quarters + * of the effective timezone and looking for DST changes - + * if found, the timezone name (EEST) is inserted into + * the lexical lookup table with type tLOCAL_ZONE. + * (Search for 'quarter' comment in 'parse_date'). + */ +local_zone: + tLOCAL_ZONE { + pc->local_isdst = $1; + pc->dsts_seen += (0 < $1); + } + | tLOCAL_ZONE tDST { + pc->local_isdst = 1; + pc->dsts_seen += (0 < $1) + 1; + } +; + +/** + * Note 'T' is a special case, as it is used as the separator in ISO + * 8601 date and time of day representation. + */ +zone: + tZONE { + pc->time_zone = $1; + } + | 'T' { + pc->time_zone = HOUR(7); + } + | tZONE relunit_snumber { + pc->time_zone = $1; + apply_relative_time (pc, $2, 1); + } + | 'T' relunit_snumber { + pc->time_zone = HOUR(7); + apply_relative_time (pc, $2, 1); + } + | tZONE tSNUMBER o_colon_minutes { + if (! time_zone_hhmm (pc, $2, $3)) YYABORT; + pc->time_zone += $1; + } + | tDAYZONE { + pc->time_zone = $1 + 60; + } + | tZONE tDST { + pc->time_zone = $1 + 60; + } +; + +day: + tDAY { + pc->day_ordinal = 0; + pc->day_number = $1; + } + | tDAY ',' { + pc->day_ordinal = 0; + pc->day_number = $1; + } + | tORDINAL tDAY { + pc->day_ordinal = $1; + pc->day_number = $2; + } + | tUNUMBER tDAY { + pc->day_ordinal = $1.value; + pc->day_number = $2; + } +; + +date: + tUNUMBER '/' tUNUMBER { + pc->month = $1.value; + pc->day = $3.value; + } + | tUNUMBER '/' tUNUMBER '/' tUNUMBER { + /** + * Interpret as YYYY/MM/DD if the first value has 4 or more digits, + * otherwise as MM/DD/YY. + * The goal in recognizing YYYY/MM/DD is solely to support legacy + * machine-generated dates like those in an RCS log listing. If + * you want portability, use the ISO 8601 format. + */ + if (4 <= $1.digits) { + pc->year = $1; + pc->month = $3.value; + pc->day = $5.value; + } else { + pc->month = $1.value; + pc->day = $3.value; + pc->year = $5; + } + } + | tUNUMBER tMONTH tSNUMBER { + /* e.g. 17-JUN-1992. */ + pc->day = $1.value; + pc->month = $2; + pc->year.value = -$3.value; + pc->year.digits = $3.digits; + } + | tMONTH tSNUMBER tSNUMBER { + /* e.g. JUN-17-1992. */ + pc->month = $1; + pc->day = -$2.value; + pc->year.value = -$3.value; + pc->year.digits = $3.digits; + } + | tMONTH tUNUMBER { + pc->month = $1; + pc->day = $2.value; + } + | tMONTH tUNUMBER ',' tUNUMBER { + pc->month = $1; + pc->day = $2.value; + pc->year = $4; + } + | tUNUMBER tMONTH { + pc->day = $1.value; + pc->month = $2; + } + | tUNUMBER tMONTH tUNUMBER { + pc->day = $1.value; + pc->month = $2; + pc->year = $3; + } + | iso_8601_date +; + +iso_8601_date: + tUNUMBER tSNUMBER tSNUMBER { + /* ISO 8601 format.YYYY-MM-DD. */ + pc->year = $1; + pc->month = -$2.value; + pc->day = -$3.value; + } +; + +rel: + relunit tAGO + { apply_relative_time (pc, $1, $2); } + | relunit + { apply_relative_time (pc, $1, 1); } + | dayshift + { apply_relative_time (pc, $1, 1); } +; + +relunit: + tORDINAL tYEAR_UNIT + { $$ = RELATIVE_TIME_0; $$.year = $1; } + | tUNUMBER tYEAR_UNIT + { $$ = RELATIVE_TIME_0; $$.year = $1.value; } + | tYEAR_UNIT + { $$ = RELATIVE_TIME_0; $$.year = 1; } + | tORDINAL tMONTH_UNIT + { $$ = RELATIVE_TIME_0; $$.month = $1; } + | tUNUMBER tMONTH_UNIT + { $$ = RELATIVE_TIME_0; $$.month = $1.value; } + | tMONTH_UNIT + { $$ = RELATIVE_TIME_0; $$.month = 1; } + | tORDINAL tDAY_UNIT + { $$ = RELATIVE_TIME_0; $$.day = $1 * $2; } + | tUNUMBER tDAY_UNIT + { $$ = RELATIVE_TIME_0; $$.day = $1.value * $2; } + | tDAY_UNIT + { $$ = RELATIVE_TIME_0; $$.day = $1; } + | tORDINAL tHOUR_UNIT + { $$ = RELATIVE_TIME_0; $$.hour = $1; } + | tUNUMBER tHOUR_UNIT + { $$ = RELATIVE_TIME_0; $$.hour = $1.value; } + | tHOUR_UNIT + { $$ = RELATIVE_TIME_0; $$.hour = 1; } + | tORDINAL tMINUTE_UNIT + { $$ = RELATIVE_TIME_0; $$.minutes = $1; } + | tUNUMBER tMINUTE_UNIT + { $$ = RELATIVE_TIME_0; $$.minutes = $1.value; } + | tMINUTE_UNIT + { $$ = RELATIVE_TIME_0; $$.minutes = 1; } + | tORDINAL tSEC_UNIT + { $$ = RELATIVE_TIME_0; $$.seconds = $1; } + | tUNUMBER tSEC_UNIT + { $$ = RELATIVE_TIME_0; $$.seconds = $1.value; } + | tSDECIMAL_NUMBER tSEC_UNIT { + $$ = RELATIVE_TIME_0; + $$.seconds = $1.tv_sec; + $$.ns = $1.tv_nsec; + } + | tUDECIMAL_NUMBER tSEC_UNIT { + $$ = RELATIVE_TIME_0; + $$.seconds = $1.tv_sec; + $$.ns = $1.tv_nsec; + } + | tSEC_UNIT + { $$ = RELATIVE_TIME_0; $$.seconds = 1; } + | relunit_snumber +; + +relunit_snumber: + tSNUMBER tYEAR_UNIT + { $$ = RELATIVE_TIME_0; $$.year = $1.value; } + | tSNUMBER tMONTH_UNIT + { $$ = RELATIVE_TIME_0; $$.month = $1.value; } + | tSNUMBER tDAY_UNIT + { $$ = RELATIVE_TIME_0; $$.day = $1.value * $2; } + | tSNUMBER tHOUR_UNIT + { $$ = RELATIVE_TIME_0; $$.hour = $1.value; } + | tSNUMBER tMINUTE_UNIT + { $$ = RELATIVE_TIME_0; $$.minutes = $1.value; } + | tSNUMBER tSEC_UNIT + { $$ = RELATIVE_TIME_0; $$.seconds = $1.value; } +; + +dayshift: + tDAY_SHIFT + { $$ = RELATIVE_TIME_0; $$.day = $1; } +; + +seconds: signed_seconds | unsigned_seconds; + +signed_seconds: + tSDECIMAL_NUMBER + | tSNUMBER + { $$.tv_sec = $1.value; $$.tv_nsec = 0; } +; + +unsigned_seconds: + tUDECIMAL_NUMBER + | tUNUMBER + { $$.tv_sec = $1.value; $$.tv_nsec = 0; } +; + +number: + tUNUMBER + { digits_to_date_time (pc, $1); } +; + +hybrid: + tUNUMBER relunit_snumber { + /** + * Hybrid all-digit and relative offset, so that we accept e.g., + * "YYYYMMDD +N days" as well as "YYYYMMDD N days". + */ + digits_to_date_time (pc, $1); + apply_relative_time (pc, $2, 1); + } +; + +o_colon_minutes: + /* empty */ + { $$.value = $$.digits = 0; } + | ':' tUNUMBER { + $$ = $2; + } +; + +%% + +static table const meridian_table[] = { + { "AM", tMERIDIAN, MERam }, + { "A.M.", tMERIDIAN, MERam }, + { "PM", tMERIDIAN, MERpm }, + { "P.M.", tMERIDIAN, MERpm }, + { NULL, 0, 0 } +}; + +static table const dst_table[] = { + { "DST", tDST, 0 } +}; + +static table const month_and_day_table[] = { + { "JANUARY", tMONTH, 1 }, + { "FEBRUARY", tMONTH, 2 }, + { "MARCH", tMONTH, 3 }, + { "APRIL", tMONTH, 4 }, + { "MAY", tMONTH, 5 }, + { "JUNE", tMONTH, 6 }, + { "JULY", tMONTH, 7 }, + { "AUGUST", tMONTH, 8 }, + { "SEPTEMBER",tMONTH, 9 }, + { "SEPT", tMONTH, 9 }, + { "OCTOBER", tMONTH, 10 }, + { "NOVEMBER", tMONTH, 11 }, + { "DECEMBER", tMONTH, 12 }, + { "SUNDAY", tDAY, 0 }, + { "MONDAY", tDAY, 1 }, + { "TUESDAY", tDAY, 2 }, + { "TUES", tDAY, 2 }, + { "WEDNESDAY",tDAY, 3 }, + { "WEDNES", tDAY, 3 }, + { "THURSDAY", tDAY, 4 }, + { "THUR", tDAY, 4 }, + { "THURS", tDAY, 4 }, + { "FRIDAY", tDAY, 5 }, + { "SATURDAY", tDAY, 6 }, + { NULL, 0, 0 } +}; + +static table const time_units_table[] = { + { "YEAR", tYEAR_UNIT, 1 }, + { "MONTH", tMONTH_UNIT, 1 }, + { "FORTNIGHT",tDAY_UNIT, 14 }, + { "WEEK", tDAY_UNIT, 7 }, + { "DAY", tDAY_UNIT, 1 }, + { "HOUR", tHOUR_UNIT, 1 }, + { "MINUTE", tMINUTE_UNIT, 1 }, + { "MIN", tMINUTE_UNIT, 1 }, + { "SECOND", tSEC_UNIT, 1 }, + { "SEC", tSEC_UNIT, 1 }, + { NULL, 0, 0 } +}; + +/* Assorted relative-time words. */ +static table const relative_time_table[] = { + { "TOMORROW", tDAY_SHIFT, 1 }, + { "YESTERDAY",tDAY_SHIFT, -1 }, + { "TODAY", tDAY_SHIFT, 0 }, + { "NOW", tDAY_SHIFT, 0 }, + { "LAST", tORDINAL, -1 }, + { "THIS", tORDINAL, 0 }, + { "NEXT", tORDINAL, 1 }, + { "FIRST", tORDINAL, 1 }, + /*{ "SECOND", tORDINAL, 2 }, */ + { "THIRD", tORDINAL, 3 }, + { "FOURTH", tORDINAL, 4 }, + { "FIFTH", tORDINAL, 5 }, + { "SIXTH", tORDINAL, 6 }, + { "SEVENTH", tORDINAL, 7 }, + { "EIGHTH", tORDINAL, 8 }, + { "NINTH", tORDINAL, 9 }, + { "TENTH", tORDINAL, 10 }, + { "ELEVENTH", tORDINAL, 11 }, + { "TWELFTH", tORDINAL, 12 }, + { "AGO", tAGO, -1 }, + { "HENCE", tAGO, 1 }, + { NULL, 0, 0 } +}; + +/** + * The universal time zone table. These labels can be used even for + * timestamps that would not otherwise be valid, e.g., GMT timestamps + * in London during summer. + */ +static table const universal_time_zone_table[] = { + { "GMT", tZONE, HOUR ( 0) }, /* Greenwich Mean */ + { "UT", tZONE, HOUR ( 0) }, /* Universal (Coordinated) */ + { "UTC", tZONE, HOUR ( 0) }, + { NULL, 0, 0 } +}; + +/** + * The time zone table. This table is necessarily incomplete, as time + * zone abbreviations are ambiguous; e.g. Australians interpret "EST" + * as Eastern time in Australia, not as US Eastern Standard Time. + * You cannot rely on parse_date to handle arbitrary time zone + * abbreviations; use numeric abbreviations like "-0500" instead. + */ +static table const time_zone_table[] = { + { "WET", tZONE, HOUR ( 0) }, /* Western European */ + { "WEST", tDAYZONE, HOUR ( 0) }, /* Western European Summer */ + { "BST", tDAYZONE, HOUR ( 0) }, /* British Summer */ + { "ART", tZONE, -HOUR ( 3) }, /* Argentina */ + { "BRT", tZONE, -HOUR ( 3) }, /* Brazil */ + { "BRST", tDAYZONE, -HOUR ( 3) }, /* Brazil Summer */ + { "NST", tZONE, -(HOUR ( 3) + 30) }, /* Newfoundland Standard */ + { "NDT", tDAYZONE,-(HOUR ( 3) + 30) }, /* Newfoundland Daylight */ + { "AST", tZONE, -HOUR ( 4) }, /* Atlantic Standard */ + { "ADT", tDAYZONE, -HOUR ( 4) }, /* Atlantic Daylight */ + { "CLT", tZONE, -HOUR ( 4) }, /* Chile */ + { "CLST", tDAYZONE, -HOUR ( 4) }, /* Chile Summer */ + { "EST", tZONE, -HOUR ( 5) }, /* Eastern Standard */ + { "EDT", tDAYZONE, -HOUR ( 5) }, /* Eastern Daylight */ + { "CST", tZONE, -HOUR ( 6) }, /* Central Standard */ + { "CDT", tDAYZONE, -HOUR ( 6) }, /* Central Daylight */ + { "MST", tZONE, -HOUR ( 7) }, /* Mountain Standard */ + { "MDT", tDAYZONE, -HOUR ( 7) }, /* Mountain Daylight */ + { "PST", tZONE, -HOUR ( 8) }, /* Pacific Standard */ + { "PDT", tDAYZONE, -HOUR ( 8) }, /* Pacific Daylight */ + { "AKST", tZONE, -HOUR ( 9) }, /* Alaska Standard */ + { "AKDT", tDAYZONE, -HOUR ( 9) }, /* Alaska Daylight */ + { "HST", tZONE, -HOUR (10) }, /* Hawaii Standard */ + { "HAST", tZONE, -HOUR (10) }, /* Hawaii-Aleutian Standard */ + { "HADT", tDAYZONE, -HOUR (10) }, /* Hawaii-Aleutian Daylight */ + { "SST", tZONE, -HOUR (12) }, /* Samoa Standard */ + { "WAT", tZONE, HOUR ( 1) }, /* West Africa */ + { "CET", tZONE, HOUR ( 1) }, /* Central European */ + { "CEST", tDAYZONE, HOUR ( 1) }, /* Central European Summer */ + { "MET", tZONE, HOUR ( 1) }, /* Middle European */ + { "MEZ", tZONE, HOUR ( 1) }, /* Middle European */ + { "MEST", tDAYZONE, HOUR ( 1) }, /* Middle European Summer */ + { "MESZ", tDAYZONE, HOUR ( 1) }, /* Middle European Summer */ + { "EET", tZONE, HOUR ( 2) }, /* Eastern European */ + { "EEST", tDAYZONE, HOUR ( 2) }, /* Eastern European Summer */ + { "CAT", tZONE, HOUR ( 2) }, /* Central Africa */ + { "SAST", tZONE, HOUR ( 2) }, /* South Africa Standard */ + { "EAT", tZONE, HOUR ( 3) }, /* East Africa */ + { "MSK", tZONE, HOUR ( 3) }, /* Moscow */ + { "MSD", tDAYZONE, HOUR ( 3) }, /* Moscow Daylight */ + { "IST", tZONE, (HOUR ( 5) + 30) }, /* India Standard */ + { "SGT", tZONE, HOUR ( 8) }, /* Singapore */ + { "KST", tZONE, HOUR ( 9) }, /* Korea Standard */ + { "JST", tZONE, HOUR ( 9) }, /* Japan Standard */ + { "GST", tZONE, HOUR (10) }, /* Guam Standard */ + { "NZST", tZONE, HOUR (12) }, /* New Zealand Standard */ + { "NZDT", tDAYZONE, HOUR (12) }, /* New Zealand Daylight */ + { NULL, 0, 0 } +}; + +/** + * Military time zone table. + * + * Note 'T' is a special case, as it is used as the separator in ISO + * 8601 date and time of day representation. + */ +static table const military_table[] = { + { "A", tZONE, -HOUR ( 1) }, + { "B", tZONE, -HOUR ( 2) }, + { "C", tZONE, -HOUR ( 3) }, + { "D", tZONE, -HOUR ( 4) }, + { "E", tZONE, -HOUR ( 5) }, + { "F", tZONE, -HOUR ( 6) }, + { "G", tZONE, -HOUR ( 7) }, + { "H", tZONE, -HOUR ( 8) }, + { "I", tZONE, -HOUR ( 9) }, + { "K", tZONE, -HOUR (10) }, + { "L", tZONE, -HOUR (11) }, + { "M", tZONE, -HOUR (12) }, + { "N", tZONE, HOUR ( 1) }, + { "O", tZONE, HOUR ( 2) }, + { "P", tZONE, HOUR ( 3) }, + { "Q", tZONE, HOUR ( 4) }, + { "R", tZONE, HOUR ( 5) }, + { "S", tZONE, HOUR ( 6) }, + { "T", 'T', 0 }, + { "U", tZONE, HOUR ( 8) }, + { "V", tZONE, HOUR ( 9) }, + { "W", tZONE, HOUR (10) }, + { "X", tZONE, HOUR (11) }, + { "Y", tZONE, HOUR (12) }, + { "Z", tZONE, HOUR ( 0) }, + { NULL, 0, 0 } +}; + +/** + * Convert a time offset expressed as HH:MM or HHMM into an integer count of + * minutes. If hh is more than 2 digits then it is of the form HHMM and must be + * delimited; in that case 'mm' is required to be absent. Otherwise, hh and mm + * are used ('mm' contains digits that were prefixed with a colon). + * + * POSIX TZ and ISO 8601 both define the maximum offset as 24:59. POSIX also + * allows seconds, but currently the parser rejects them. Both require minutes + * to be zero padded (2 digits). ISO requires hours to be zero padded, POSIX + * does not, either is accepted; which means an invalid ISO offset could pass. + */ + +static int time_zone_hhmm(parser_control *pc, textint hh, textint mm) +{ + int h, m; + + if (hh.digits > 2 && hh.digits < 5 && mm.digits == 0) { + h = hh.value / 100; + m = hh.value % 100; + } else if (hh.digits < 3 && (mm.digits == 0 || mm.digits == 2)) { + h = hh.value; + m = hh.negative ? -mm.value : mm.value; + } else + return 0; + + if (abs(h) > 24 || abs(m) > 59) + return 0; + + pc->time_zone = h * 60 + m; + return 1; +} + +static int to_hour(intmax_t hours, int meridian) +{ + switch (meridian) { + default: /* Pacify GCC. */ + case MER24: + return 0 <= hours && hours < 24 ? hours : -1; + case MERam: + return 0 < hours && hours < 12 ? hours : hours == 12 ? 0 : -1; + case MERpm: + return 0 < hours && hours < 12 ? hours + 12 : hours == 12 ? 12 : -1; + } +} + +static long int to_year(textint textyear) +{ + intmax_t year = textyear.value; + + if (year < 0) + year = -year; + + /** + * XPG4 suggests that years 00-68 map to 2000-2068, and + * years 69-99 map to 1969-1999. + */ + else if (textyear.digits == 2) + year += year < 69 ? 2000 : 1900; + + return year; +} + +static table const * lookup_zone(parser_control const *pc, char const *name) +{ + table const *tp; + + for (tp = universal_time_zone_table; tp->name; tp++) + if (strcmp (name, tp->name) == 0) + return tp; + + /** + * Try local zone abbreviations before those in time_zone_table, as + * the local ones are more likely to be right. + */ + for (tp = pc->local_time_zone_table; tp->name; tp++) + if (strcmp (name, tp->name) == 0) + return tp; + + for (tp = time_zone_table; tp->name; tp++) + if (strcmp (name, tp->name) == 0) + return tp; + + return NULL; +} + +#if ! HAVE_TM_GMTOFF +/** + * Yield the difference between *A and *B, + * measured in seconds, ignoring leap seconds. + * The body of this function is taken directly from the GNU C Library; + * see src/strftime.c. + */ +static int tm_diff(struct tm const *a, struct tm const *b) +{ + /** + * Compute intervening leap days correctly even if year is negative. + * Take care to avoid int overflow in leap day calculations. + */ + int a4 = SHR (a->tm_year, 2) + SHR (TM_YEAR_BASE, 2) - ! (a->tm_year & 3); + int b4 = SHR (b->tm_year, 2) + SHR (TM_YEAR_BASE, 2) - ! (b->tm_year & 3); + int a100 = a4 / 25 - (a4 % 25 < 0); + int b100 = b4 / 25 - (b4 % 25 < 0); + int a400 = SHR (a100, 2); + int b400 = SHR (b100, 2); + int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400); + int years = a->tm_year - b->tm_year; + int days = (365 * years + intervening_leap_days + + (a->tm_yday - b->tm_yday)); + return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour)) + + (a->tm_min - b->tm_min)) + + (a->tm_sec - b->tm_sec)); +} +#endif /* ! HAVE_TM_GMTOFF */ + +static table const * lookup_word(parser_control const *pc, char *word) +{ + char *p; + char *q; + size_t wordlen; + table const *tp; + int period_found; + int abbrev; + + /* Make it uppercase. */ + for (p = word; *p; p++) + *p = c_toupper (to_uchar (*p)); + + for (tp = meridian_table; tp->name; tp++) + if (strcmp (word, tp->name) == 0) + return tp; + + /* See if we have an abbreviation for a month. */ + wordlen = strlen (word); + abbrev = wordlen == 3 || (wordlen == 4 && word[3] == '.'); + + for (tp = month_and_day_table; tp->name; tp++) + if ((abbrev ? strncmp (word, tp->name, 3) : + strcmp (word, tp->name)) == 0) + return tp; + + if ((tp = lookup_zone (pc, word))) + return tp; + + if (strcmp (word, dst_table[0].name) == 0) + return dst_table; + + for (tp = time_units_table; tp->name; tp++) + if (strcmp (word, tp->name) == 0) + return tp; + + /* Strip off any plural and try the units table again. */ + if (word[wordlen - 1] == 'S') { + word[wordlen - 1] = '\0'; + for (tp = time_units_table; tp->name; tp++) + if (strcmp (word, tp->name) == 0) + return tp; + word[wordlen - 1] = 'S'; /* For "this" in relative_time_table. */ + } + + for (tp = relative_time_table; tp->name; tp++) + if (strcmp (word, tp->name) == 0) + return tp; + + /* Military time zones. */ + if (wordlen == 1) + for (tp = military_table; tp->name; tp++) + if (word[0] == tp->name[0]) + return tp; + + /* Drop out any periods and try the time zone table again. */ + for (period_found = 0, p = q = word; (*p = *q); q++) + if (*q == '.') + period_found = 1; + else + p++; + if (period_found && (tp = lookup_zone (pc, word))) + return tp; + + return NULL; +} + +static int yylex (union YYSTYPE *lvalp, parser_control *pc) +{ + unsigned char c; + size_t count; + + for (;;) { + while (c = *pc->input, c_isspace (c)) + pc->input++; + + if (c_isdigit (c) || c == '-' || c == '+') { + char const *p; + int sign; + uintmax_t value; + if (c == '-' || c == '+') { + sign = c == '-' ? -1 : 1; + while (c = *++pc->input, c_isspace (c)) + continue; + if (! c_isdigit (c)) + /* skip the '-' sign */ + continue; + } else + sign = 0; + p = pc->input; + for (value = 0; ; value *= 10) { + uintmax_t value1 = value + (c - '0'); + if (value1 < value) + return '?'; + value = value1; + c = *++p; + if (! c_isdigit (c)) + break; + if (UINTMAX_MAX / 10 < value) + return '?'; + } + if ((c == '.' || c == ',') && c_isdigit (p[1])) { + time_t s; + int ns; + int digits; + uintmax_t value1; + + /* Check for overflow when converting value to + * time_t. + */ + if (sign < 0) { + s = - value; + if (0 < s) + return '?'; + value1 = -s; + } else { + s = value; + if (s < 0) + return '?'; + value1 = s; + } + if (value != value1) + return '?'; + + /* Accumulate fraction, to ns precision. */ + p++; + ns = *p++ - '0'; + for (digits = 2; + digits <= LOG10_BILLION; digits++) { + ns *= 10; + if (c_isdigit (*p)) + ns += *p++ - '0'; + } + + /* Skip excess digits, truncating toward + * -Infinity. + */ + if (sign < 0) + for (; c_isdigit (*p); p++) + if (*p != '0') { + ns++; + break; + } + while (c_isdigit (*p)) + p++; + + /* Adjust to the timespec convention, which is + * that tv_nsec is always a positive offset even + * if tv_sec is negative. + */ + if (sign < 0 && ns) { + s--; + if (! (s < 0)) + return '?'; + ns = BILLION - ns; + } + + lvalp->timespec.tv_sec = s; + lvalp->timespec.tv_nsec = ns; + pc->input = p; + return + sign ? tSDECIMAL_NUMBER : tUDECIMAL_NUMBER; + } else { + lvalp->textintval.negative = sign < 0; + if (sign < 0) { + lvalp->textintval.value = - value; + if (0 < lvalp->textintval.value) + return '?'; + } else { + lvalp->textintval.value = value; + if (lvalp->textintval.value < 0) + return '?'; + } + lvalp->textintval.digits = p - pc->input; + pc->input = p; + return sign ? tSNUMBER : tUNUMBER; + } + } + + if (c_isalpha (c)) { + char buff[20]; + char *p = buff; + table const *tp; + + do { + if (p < buff + sizeof buff - 1) + *p++ = c; + c = *++pc->input; + } + while (c_isalpha (c) || c == '.'); + + *p = '\0'; + tp = lookup_word (pc, buff); + if (! tp) { + return '?'; + } + lvalp->intval = tp->value; + return tp->type; + } + + if (c != '(') + return to_uchar (*pc->input++); + + count = 0; + do { + c = *pc->input++; + if (c == '\0') + return c; + if (c == '(') + count++; + else if (c == ')') + count--; + } + while (count != 0); + } +} + +/* Do nothing if the parser reports an error. */ +static int yyerror(parser_control const *pc __attribute__((__unused__)), + char const *s __attribute__((__unused__))) +{ + return 0; +} + +/** + * If *TM0 is the old and *TM1 is the new value of a struct tm after + * passing it to mktime, return 1 if it's OK that mktime returned T. + * It's not OK if *TM0 has out-of-range members. + */ + +static int mktime_ok(struct tm const *tm0, struct tm const *tm1, time_t t) +{ + if (t == (time_t) -1) { + /** + * Guard against falsely reporting an error when parsing a + * timestamp that happens to equal (time_t) -1, on a host that + * supports such a timestamp. + */ + tm1 = localtime (&t); + if (!tm1) + return 0; + } + + return ! ((tm0->tm_sec ^ tm1->tm_sec) + | (tm0->tm_min ^ tm1->tm_min) + | (tm0->tm_hour ^ tm1->tm_hour) + | (tm0->tm_mday ^ tm1->tm_mday) + | (tm0->tm_mon ^ tm1->tm_mon) + | (tm0->tm_year ^ tm1->tm_year)); +} + +/** + * A reasonable upper bound for the size of ordinary TZ strings. + * Use heap allocation if TZ's length exceeds this. + */ +enum { TZBUFSIZE = 100 }; + +/** + * Return a copy of TZ, stored in TZBUF if it fits, and heap-allocated + * otherwise. + */ +static char * get_tz(char tzbuf[TZBUFSIZE]) +{ + char *tz = getenv ("TZ"); + if (tz) { + size_t tzsize = strlen (tz) + 1; + tz = (tzsize <= TZBUFSIZE + ? memcpy (tzbuf, tz, tzsize) + : strdup (tz)); + } + return tz; +} + +/** + * Parse a date/time string, storing the resulting time value into *result. + * The string itself is pointed to by *p. Return 1 if successful. + * *p can be an incomplete or relative time specification; if so, use + * *now as the basis for the returned time. + */ +int parse_date(struct timespec *result, char const *p, + struct timespec const *now) +{ + time_t Start; + intmax_t Start_ns; + struct tm const *tmp; + struct tm tm; + struct tm tm0; + parser_control pc; + struct timespec gettime_buffer; + unsigned char c; + int tz_was_altered = 0; + char *tz0 = NULL; + char tz0buf[TZBUFSIZE]; + int ok = 1; + struct timeval tv; + + if (! now) { + gettimeofday (&tv, NULL); + gettime_buffer.tv_sec = tv.tv_sec; + gettime_buffer.tv_nsec = tv.tv_usec * 1000; + now = &gettime_buffer; + } + + Start = now->tv_sec; + Start_ns = now->tv_nsec; + + tmp = localtime (&now->tv_sec); + if (! tmp) + return 0; + + while (c = *p, c_isspace (c)) + p++; + + if (strncmp (p, "TZ=\"", 4) == 0) { + char const *tzbase = p + 4; + size_t tzsize = 1; + char const *s; + + for (s = tzbase; *s; s++, tzsize++) + if (*s == '\\') { + s++; + if (! (*s == '\\' || *s == '"')) + break; + } else if (*s == '"') { + char *z; + char *tz1; + char tz1buf[TZBUFSIZE]; + int large_tz = TZBUFSIZE < tzsize; + int setenv_ok; + + tz0 = get_tz (tz0buf); + if (!tz0) + goto fail; + + if (large_tz) { + z = tz1 = malloc (tzsize); + if (!tz1) + goto fail; + } else + z = tz1 = tz1buf; + + for (s = tzbase; *s != '"'; s++) + *z++ = *(s += *s == '\\'); + *z = '\0'; + setenv_ok = setenv ("TZ", tz1, 1) == 0; + if (large_tz) + free (tz1); + if (!setenv_ok) + goto fail; + tz_was_altered = 1; + + p = s + 1; + while (c = *p, c_isspace (c)) + p++; + + break; + } + } + + /** + * As documented, be careful to treat the empty string just like + * a date string of "0". Without this, an empty string would be + * declared invalid when parsed during a DST transition. + */ + if (*p == '\0') + p = "0"; + + pc.input = p; + pc.year.value = tmp->tm_year; + pc.year.value += TM_YEAR_BASE; + pc.year.digits = 0; + pc.month = tmp->tm_mon + 1; + pc.day = tmp->tm_mday; + pc.hour = tmp->tm_hour; + pc.minutes = tmp->tm_min; + pc.seconds.tv_sec = tmp->tm_sec; + pc.seconds.tv_nsec = Start_ns; + tm.tm_isdst = tmp->tm_isdst; + + pc.meridian = MER24; + pc.rel = RELATIVE_TIME_0; + pc.timespec_seen = 0; + pc.rels_seen = 0; + pc.dates_seen = 0; + pc.days_seen = 0; + pc.times_seen = 0; + pc.local_zones_seen = 0; + pc.dsts_seen = 0; + pc.zones_seen = 0; + +#if HAVE_STRUCT_TM_TM_ZONE + pc.local_time_zone_table[0].name = tmp->tm_zone; + pc.local_time_zone_table[0].type = tLOCAL_ZONE; + pc.local_time_zone_table[0].value = tmp->tm_isdst; + pc.local_time_zone_table[1].name = NULL; + + /** + * Probe the names used in the next three calendar quarters, looking + * for a tm_isdst different from the one we already have. + */ + { + int quarter; + for (quarter = 1; quarter <= 3; quarter++) { + time_t probe = Start + quarter * (90 * 24 * 60 * 60); + struct tm const *probe_tm = localtime (&probe); + if (probe_tm && probe_tm->tm_zone + && probe_tm->tm_isdst + != pc.local_time_zone_table[0].value) { + { + pc.local_time_zone_table[1].name + = probe_tm->tm_zone; + pc.local_time_zone_table[1].type + = tLOCAL_ZONE; + pc.local_time_zone_table[1].value + = probe_tm->tm_isdst; + pc.local_time_zone_table[2].name + = NULL; + } + break; + } + } + } +#else +#if HAVE_TZNAME + { +# if !HAVE_DECL_TZNAME + extern char *tzname[]; +# endif + int i; + for (i = 0; i < 2; i++) { + pc.local_time_zone_table[i].name = tzname[i]; + pc.local_time_zone_table[i].type = tLOCAL_ZONE; + pc.local_time_zone_table[i].value = i; + } + pc.local_time_zone_table[i].name = NULL; + } +#else + pc.local_time_zone_table[0].name = NULL; +#endif +#endif + + if (pc.local_time_zone_table[0].name && pc.local_time_zone_table[1].name + && ! strcmp (pc.local_time_zone_table[0].name, + pc.local_time_zone_table[1].name)) { + /** + * This locale uses the same abbreviation for standard and + * daylight times. So if we see that abbreviation, we don't + * know whether it's daylight time. + */ + pc.local_time_zone_table[0].value = -1; + pc.local_time_zone_table[1].name = NULL; + } + + if (yyparse (&pc) != 0) { + goto fail; + } + + if (pc.timespec_seen) + *result = pc.seconds; + else { + if (1 < (pc.times_seen | pc.dates_seen | pc.days_seen + | pc.dsts_seen + | (pc.local_zones_seen + pc.zones_seen))) { + goto fail; + } + + tm.tm_year = to_year (pc.year) - TM_YEAR_BASE; + tm.tm_mon = pc.month - 1; + tm.tm_mday = pc.day; + if (pc.times_seen || (pc.rels_seen && + ! pc.dates_seen && ! pc.days_seen)) { + tm.tm_hour = to_hour (pc.hour, pc.meridian); + if (tm.tm_hour < 0) { + goto fail; + } + tm.tm_min = pc.minutes; + tm.tm_sec = pc.seconds.tv_sec; + } else { + tm.tm_hour = tm.tm_min = tm.tm_sec = 0; + pc.seconds.tv_nsec = 0; + } + + /** + * Let mktime deduce tm_isdst if we have an absolute timestamp. + */ + if (pc.dates_seen | pc.days_seen | pc.times_seen) + tm.tm_isdst = -1; + + /** + * But if the input explicitly specifies local time with or + * without DST, give mktime that information. + */ + if (pc.local_zones_seen) + tm.tm_isdst = pc.local_isdst; + + tm0 = tm; + + Start = mktime (&tm); + + if (! mktime_ok (&tm0, &tm, Start)) { + if (! pc.zones_seen) { + goto fail; + } else { + /** Guard against falsely reporting errors near + * the time_t boundaries when parsing times in + * other time zones. For example, suppose the + * input string "1969-12-31 23:00:00 -0100", the + * current time zone is 8 hours ahead of UTC, + * and the min time_t value is 1970-01-01 + * 00:00:00 UTC. Then the min localtime value + * is 1970-01-01 08:00:00, and mktime will + * therefore fail on 1969-12-31 23:00:00. To + * work around the problem, set the time zone to + * 1 hour behind UTC temporarily by setting + * TZ="XXX1:00" and try mktime again. + */ + + intmax_t time_zone = pc.time_zone; + + intmax_t abs_time_zone = time_zone < 0 + ? - time_zone : time_zone; + + intmax_t abs_time_zone_hour + = abs_time_zone / 60; + + int abs_time_zone_min = abs_time_zone % 60; + + char tz1buf[sizeof "XXX+0:00" + + sizeof pc.time_zone + * CHAR_BIT / 3]; + + if (!tz_was_altered) + tz0 = get_tz (tz0buf); + sprintf (tz1buf, "XXX%s%jd:%02d", + &"-"[time_zone < 0], + abs_time_zone_hour, + abs_time_zone_min); + if (setenv ("TZ", tz1buf, 1) != 0) { + goto fail; + } + tz_was_altered = 1; + tm = tm0; + Start = mktime (&tm); + if (! mktime_ok (&tm0, &tm, Start)) { + goto fail; + } + } + } + + if (pc.days_seen && ! pc.dates_seen) { + tm.tm_mday += ((pc.day_number - tm.tm_wday + 7) % 7 + 7 + * (pc.day_ordinal + - (0 < pc.day_ordinal + && tm.tm_wday != pc.day_number))); + tm.tm_isdst = -1; + Start = mktime (&tm); + if (Start == (time_t) -1) { + goto fail; + } + } + /* Add relative date. */ + if (pc.rel.year | pc.rel.month | pc.rel.day) { + int year = tm.tm_year + pc.rel.year; + int month = tm.tm_mon + pc.rel.month; + int day = tm.tm_mday + pc.rel.day; + if (((year < tm.tm_year) ^ (pc.rel.year < 0)) + | ((month < tm.tm_mon) ^ (pc.rel.month < 0)) + | ((day < tm.tm_mday) ^ (pc.rel.day < 0))) { + goto fail; + } + tm.tm_year = year; + tm.tm_mon = month; + tm.tm_mday = day; + tm.tm_hour = tm0.tm_hour; + tm.tm_min = tm0.tm_min; + tm.tm_sec = tm0.tm_sec; + tm.tm_isdst = tm0.tm_isdst; + Start = mktime (&tm); + if (Start == (time_t) -1) { + goto fail; + } + } + + /** + * The only "output" of this if-block is an updated Start value, + * so this block must follow others that clobber Start. + */ + if (pc.zones_seen) { + intmax_t delta = pc.time_zone * 60; + time_t t1; +#ifdef HAVE_TM_GMTOFF + delta -= tm.tm_gmtoff; +#else + time_t t = Start; + struct tm const *gmt = gmtime (&t); + if (! gmt) { + goto fail; + } + delta -= tm_diff (&tm, gmt); +#endif + t1 = Start - delta; + if ((Start < t1) != (delta < 0)) { + goto fail; /* time_t overflow */ + } + Start = t1; + } + + /** + * Add relative hours, minutes, and seconds. On hosts that + * support leap seconds, ignore the possibility of leap seconds; + * e.g., "+ 10 minutes" adds 600 seconds, even if one of them is + * a leap second. Typically this is not what the user wants, + * but it's too hard to do it the other way, because the time + * zone indicator must be applied before relative times, and if + * mktime is applied again the time zone will be lost. + */ + intmax_t sum_ns = pc.seconds.tv_nsec + pc.rel.ns; + intmax_t normalized_ns = (sum_ns % BILLION + BILLION) % BILLION; + time_t t0 = Start; + intmax_t d1 = 60 * 60 * pc.rel.hour; + time_t t1 = t0 + d1; + intmax_t d2 = 60 * pc.rel.minutes; + time_t t2 = t1 + d2; + time_t d3 = pc.rel.seconds; + time_t t3 = t2 + d3; + intmax_t d4 = (sum_ns - normalized_ns) / BILLION; + time_t t4 = t3 + d4; + time_t t5 = t4; + + if ((d1 / (60 * 60) ^ pc.rel.hour) + | (d2 / 60 ^ pc.rel.minutes) + | ((t1 < t0) ^ (d1 < 0)) + | ((t2 < t1) ^ (d2 < 0)) + | ((t3 < t2) ^ (d3 < 0)) + | ((t4 < t3) ^ (d4 < 0)) + | (t5 != t4)) { + goto fail; + } + result->tv_sec = t5; + result->tv_nsec = normalized_ns; + } + + goto done; + + fail: + ok = 0; + done: + if (tz_was_altered) + ok &= (tz0 ? setenv ("TZ", tz0, 1) + : unsetenv ("TZ")) == 0; + if (tz0 != tz0buf) + free (tz0); + return ok; +} |