From 64426f1a89450a0f79b723a4d966f7f9c7492c60 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Sat, 12 Mar 2022 22:43:10 -0500 Subject: Don't shadow standard headers @italic on the AUR stated that bfs from the AUR fails to build on Manjaro. From the build log, it seems like doesn't get included properly. I assume it's picking up ./time.h instead. I couldn't reproduce the build issue in the default configuration, but it does fail with EXTRA_CFLAGS="-I." which isn't good. So rename everything with an x prefix to stop clashing. Link: https://aur.archlinux.org/packages/bfs#comment-856102 Link: https://paste.rs/eqR --- xtime.c | 323 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 323 insertions(+) create mode 100644 xtime.c (limited to 'xtime.c') diff --git a/xtime.c b/xtime.c new file mode 100644 index 0000000..b83bf20 --- /dev/null +++ b/xtime.c @@ -0,0 +1,323 @@ +/**************************************************************************** + * bfs * + * Copyright (C) 2020 Tavian Barnes * + * * + * Permission to use, copy, modify, and/or distribute this software for any * + * purpose with or without fee is hereby granted. * + * * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * + ****************************************************************************/ + +#include "xtime.h" +#include +#include +#include +#include +#include + +/** Whether tzset() has been called. */ +static bool tz_is_set = false; + +int xlocaltime(const time_t *timep, struct tm *result) { + // Should be called before localtime_r() according to POSIX.1-2004 + if (!tz_is_set) { + tzset(); + tz_is_set = true; + } + + if (localtime_r(timep, result)) { + return 0; + } else { + return -1; + } +} + +int xgmtime(const time_t *timep, struct tm *result) { + // Should be called before gmtime_r() according to POSIX.1-2004 + if (!tz_is_set) { + tzset(); + tz_is_set = true; + } + + if (gmtime_r(timep, result)) { + return 0; + } else { + return -1; + } +} + +int xmktime(struct tm *tm, time_t *timep) { + *timep = mktime(tm); + + if (*timep == -1) { + int error = errno; + + struct tm tmp; + if (xlocaltime(timep, &tmp) != 0) { + return -1; + } + + if (tm->tm_year != tmp.tm_year || tm->tm_yday != tmp.tm_yday + || tm->tm_hour != tmp.tm_hour || tm->tm_min != tmp.tm_min || tm->tm_sec != tmp.tm_sec) { + errno = error; + return -1; + } + } + + return 0; +} + +static int safe_add(int *value, int delta) { + if (*value >= 0) { + if (delta > INT_MAX - *value) { + return -1; + } + } else { + if (delta < INT_MIN - *value) { + return -1; + } + } + + *value += delta; + return 0; +} + +static int floor_div(int n, int d) { + int a = n < 0; + return (n + a)/d - a; +} + +static int wrap(int *value, int max, int *next) { + int carry = floor_div(*value, max); + *value -= carry * max; + return safe_add(next, carry); +} + +static int month_length(int year, int month) { + static const int month_lengths[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; + int ret = month_lengths[month]; + if (month == 1 && year%4 == 0 && (year%100 != 0 || (year + 300)%400 == 0)) { + ++ret; + } + return ret; +} + +int xtimegm(struct tm *tm, time_t *timep) { + tm->tm_isdst = 0; + + if (wrap(&tm->tm_sec, 60, &tm->tm_min) != 0) { + goto overflow; + } + if (wrap(&tm->tm_min, 60, &tm->tm_hour) != 0) { + goto overflow; + } + if (wrap(&tm->tm_hour, 24, &tm->tm_mday) != 0) { + goto overflow; + } + + // In order to wrap the days of the month, we first need to know what + // month it is + if (wrap(&tm->tm_mon, 12, &tm->tm_year) != 0) { + goto overflow; + } + + if (tm->tm_mday < 1) { + do { + --tm->tm_mon; + if (wrap(&tm->tm_mon, 12, &tm->tm_year) != 0) { + goto overflow; + } + + tm->tm_mday += month_length(tm->tm_year, tm->tm_mon); + } while (tm->tm_mday < 1); + } else { + while (true) { + int days = month_length(tm->tm_year, tm->tm_mon); + if (tm->tm_mday <= days) { + break; + } + + tm->tm_mday -= days; + ++tm->tm_mon; + if (wrap(&tm->tm_mon, 12, &tm->tm_year) != 0) { + goto overflow; + } + } + } + + tm->tm_yday = 0; + for (int i = 0; i < tm->tm_mon; ++i) { + tm->tm_yday += month_length(tm->tm_year, i); + } + tm->tm_yday += tm->tm_mday - 1; + + int leap_days; + // Compute floor((year - 69)/4) - floor((year - 1)/100) + floor((year + 299)/400) without overflows + if (tm->tm_year >= 0) { + leap_days = floor_div(tm->tm_year - 69, 4) - floor_div(tm->tm_year - 1, 100) + floor_div(tm->tm_year - 101, 400) + 1; + } else { + leap_days = floor_div(tm->tm_year + 3, 4) - floor_div(tm->tm_year + 99, 100) + floor_div(tm->tm_year + 299, 400) - 17; + } + + long long epoch_days = 365LL*(tm->tm_year - 70) + leap_days + tm->tm_yday; + tm->tm_wday = (epoch_days + 4)%7; + if (tm->tm_wday < 0) { + tm->tm_wday += 7; + } + + long long epoch_time = tm->tm_sec + 60*(tm->tm_min + 60*(tm->tm_hour + 24*epoch_days)); + *timep = (time_t)epoch_time; + if ((long long)*timep != epoch_time) { + goto overflow; + } + return 0; + +overflow: + errno = EOVERFLOW; + return -1; +} + +/** Parse some digits from a timestamp. */ +static int parse_timestamp_part(const char **str, size_t n, int *result) { + char buf[n + 1]; + for (size_t i = 0; i < n; ++i, ++*str) { + char c = **str; + if (c < '0' || c > '9') { + return -1; + } + buf[i] = c; + } + buf[n] = '\0'; + + *result = atoi(buf); + return 0; +} + +int parse_timestamp(const char *str, struct timespec *result) { + struct tm tm = { + .tm_isdst = -1, + }; + + int tz_hour = 0; + int tz_min = 0; + bool tz_negative = false; + bool local = true; + + // YYYY + if (parse_timestamp_part(&str, 4, &tm.tm_year) != 0) { + goto invalid; + } + tm.tm_year -= 1900; + + // MM + if (*str == '-') { + ++str; + } + if (parse_timestamp_part(&str, 2, &tm.tm_mon) != 0) { + goto invalid; + } + tm.tm_mon -= 1; + + // DD + if (*str == '-') { + ++str; + } + if (parse_timestamp_part(&str, 2, &tm.tm_mday) != 0) { + goto invalid; + } + + if (!*str) { + goto end; + } else if (*str == 'T') { + ++str; + } + + // hh + if (parse_timestamp_part(&str, 2, &tm.tm_hour) != 0) { + goto invalid; + } + + // mm + if (!*str) { + goto end; + } else if (*str == ':') { + ++str; + } + if (parse_timestamp_part(&str, 2, &tm.tm_min) != 0) { + goto invalid; + } + + // ss + if (!*str) { + goto end; + } else if (*str == ':') { + ++str; + } + if (parse_timestamp_part(&str, 2, &tm.tm_sec) != 0) { + goto invalid; + } + + if (!*str) { + goto end; + } else if (*str == 'Z') { + local = false; + ++str; + } else if (*str == '+' || *str == '-') { + local = false; + tz_negative = *str == '-'; + ++str; + + // hh + if (parse_timestamp_part(&str, 2, &tz_hour) != 0) { + goto invalid; + } + + // mm + if (!*str) { + goto end; + } else if (*str == ':') { + ++str; + } + if (parse_timestamp_part(&str, 2, &tz_min) != 0) { + goto invalid; + } + } else { + goto invalid; + } + + if (*str) { + goto invalid; + } + +end: + if (local) { + if (xmktime(&tm, &result->tv_sec) != 0) { + goto error; + } + } else { + if (xtimegm(&tm, &result->tv_sec) != 0) { + goto error; + } + + int offset = 60*tz_hour + tz_min; + if (tz_negative) { + result->tv_sec -= offset; + } else { + result->tv_sec += offset; + } + } + + result->tv_nsec = 0; + return 0; + +invalid: + errno = EINVAL; +error: + return -1; +} -- cgit v1.2.3