diff options
Diffstat (limited to 'date.c')
| -rw-r--r-- | date.c | 184 |
1 files changed, 184 insertions, 0 deletions
@@ -0,0 +1,184 @@ +/* + * GIT - The information manager from hell + * + * Copyright (C) Linus Torvalds, 2005 + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include <time.h> + +static time_t my_mktime(struct tm *tm) +{ + static const int mdays[] = { + 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 + }; + int year = tm->tm_year - 70; + int month = tm->tm_mon; + int day = tm->tm_mday; + + if (year < 0 || year > 129) /* algo only works for 1970-2099 */ + return -1; + if (month < 0 || month > 11) /* array bounds */ + return -1; + if (month < 2 || (year + 2) % 4) + day--; + return (year * 365 + (year + 1) / 4 + mdays[month] + day) * 24*60*60UL + + tm->tm_hour * 60*60 + tm->tm_min * 60 + tm->tm_sec; +} + +static const char *month_names[] = { + "Jan", "Feb", "Mar", "Apr", "May", "Jun", + "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" +}; + +static const char *weekday_names[] = { + "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" +}; + + +static char *skipfws(char *str) +{ + while (isspace(*str)) + str++; + return str; +} + + +/* Gr. strptime is crap for this; it doesn't have a way to require RFC2822 + (i.e. English) day/month names, and it doesn't work correctly with %z. */ +void parse_date(char *date, char *result, int maxlen) +{ + struct tm tm; + char *p, *tz; + int i, offset; + time_t then; + + memset(&tm, 0, sizeof(tm)); + + /* Skip day-name */ + p = skipfws(date); + if (!isdigit(*p)) { + for (i=0; i<7; i++) { + if (!strncmp(p,weekday_names[i],3) && p[3] == ',') { + p = skipfws(p+4); + goto day; + } + } + return; + } + + /* day */ + day: + tm.tm_mday = strtoul(p, &p, 10); + + if (tm.tm_mday < 1 || tm.tm_mday > 31) + return; + + if (!isspace(*p)) + return; + + p = skipfws(p); + + /* month */ + + for (i=0; i<12; i++) { + if (!strncmp(p, month_names[i], 3) && isspace(p[3])) { + tm.tm_mon = i; + p = skipfws(p+strlen(month_names[i])); + goto year; + } + } + return; /* Error -- bad month */ + + /* year */ + year: + tm.tm_year = strtoul(p, &p, 10); + + if (!tm.tm_year && !isspace(*p)) + return; + + if (tm.tm_year > 1900) + tm.tm_year -= 1900; + + p=skipfws(p); + + /* hour */ + if (!isdigit(*p)) + return; + tm.tm_hour = strtoul(p, &p, 10); + + if (tm.tm_hour > 23) + return; + + if (*p != ':') + return; /* Error -- bad time */ + p++; + + /* minute */ + if (!isdigit(*p)) + return; + tm.tm_min = strtoul(p, &p, 10); + + if (tm.tm_min > 59) + return; + + if (*p != ':') + goto zone; + p++; + + /* second */ + if (!isdigit(*p)) + return; + tm.tm_sec = strtoul(p, &p, 10); + + if (tm.tm_sec > 60) + return; + + zone: + if (!isspace(*p)) + return; + + p = skipfws(p); + + if (*p == '-') + offset = -60; + else if (*p == '+') + offset = 60; + else + return; + + if (!isdigit(p[1]) || !isdigit(p[2]) || !isdigit(p[3]) || !isdigit(p[4])) + return; + + tz = p; + i = strtoul(p+1, NULL, 10); + offset *= ((i % 100) + ((i / 100) * 60)); + + p = skipfws(p + 5); + if (*p && *p != '(') /* trailing comment like (EDT) is ok */ + return; + + then = my_mktime(&tm); /* mktime uses local timezone */ + if (then == -1) + return; + + then -= offset; + + snprintf(result, maxlen, "%lu %5.5s", then, tz); +} + +void datestamp(char *buf, int bufsize) +{ + time_t now; + int offset; + + time(&now); + + offset = my_mktime(localtime(&now)) - now; + offset /= 60; + + snprintf(buf, bufsize, "%lu %+05d", now, offset/60*100 + offset%60); +} |