#include "config.h" #include "slrnfeat.h" /* Copyright (c) 1998 John E. Davis (davis@space.mit.edu) * * This file is part of slrn. * * Slrn 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 2, or (at your option) any * later version. * * Slrn 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 Slrn; see the file COPYING. If not, write to the Free * Software Foundation, 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #include #include #include #include "slrn.h" #include "util.h" #ifndef isdigit # define isdigit(x) (((x)>='0')&&((x)<='9')) #endif #ifndef isalpha # define isalpha(x) ((((x)>='A')&&((x)<='Z')) || (((x)>='A')&&((x)<='Z'))) #endif /* This routine parses the date field of a header and returns it as a time_t * object. The main difficulity is the lack of uniformity in the date formats * and the fact that there are leap years, etc... * * Grepping my news spool of more than 12000 articles revealed that the * date headers of the vast majority of headers appear in one of the * following forms: * * 03 Feb 1997 10:09:58 +0100 * 5 Feb 1997 15:32:05 GMT * Wed, 05 Feb 1997 11:58:33 -0800 * * A few look like: * Fri, 3 Jan 1997 07:35:15 -0800 (PST) * * and very few (less than 1 percent) of the articles had Date headers of the * form: * * Tue, 21 Jan 1997 14:17:31 UNDEFINED * 02 Feb 97 14:20:35 EDT * Tue, 4 Feb 1997 19:06:46 LOCAL * Tue, 3 Feb 1997 11:51:27 UT * * This means that the timezone can be assumed to be GMT or specified via an * offset from GMT. All of the above dates have the format: * * [Weekday,] Day Month Year Hour:Min:Sec Timezone * * which will make the parsing somewhat simple. * * Beware: the calculations involving leap years, etc... are naive. */ #define THE_YEAR_0 1992L /* leap year */ #define IS_LEAP_YEAR(y) (((y) % 4) == 0) typedef struct { char name[5]; int tz; } Timezone_Table_Type; static Timezone_Table_Type Timezone_Table [] = { {"EDT", -500}, {"PST", -800}, {"CST", -600}, {"MST", -700}, {"MET", 100}, /* Middle European */ {"MEZ", 100}, /* Middle European */ {"MSK", 300}, /* Moscow */ {"CET", 100}, /* Central European */ {"HKT", 800}, /* Central European */ {"JST", 900}, /* Central European */ {"CAST", 930}, /* Central Autsralian */ {"EAST", 1000}, /* Eastern Autsralian */ {"NZST", 1200}, /* New Zealand Autsralian */ {"EET", 200}, /* Eastern European */ {"", 0} }; static int parse_timezone (char *t) { char ch; Timezone_Table_Type *table; table = Timezone_Table; while (0 != (ch = table->name [0])) { if ((*t == ch) && (0 == strncmp (t, table->name, sizeof (table->name)))) return table->tz; table++; } return 0; } long slrn_date_to_order_parm (char *date) { char ch; long day, month, year, minutes, seconds, hours, tz; int sign; date = slrn_skip_whitespace (date); if ((date == NULL) || (*date == 0)) return 0; /* Look for a weekday, if found skip it */ while (isalpha (*date)) date++; if (*date == ',') date++; date = slrn_skip_whitespace (date); /* expecting "03 Feb 1997 10:09:58 +0100" */ day = 0; while (ch = *date, isdigit (ch)) { day = 10 * day + (long) (ch - '0'); date++; } if ((day == 0) || (day > 31)) return 0; day--; date = slrn_skip_whitespace (date); month = 0; switch (*date++) { default: return 0; case 'J': /* Jan, Jun, Jul */ ch = *date++; if ((ch == 'u') || (ch == 'U')) { ch = *date++; if ((ch == 'n') || (ch == 'N')) month = 6; else if ((ch == 'l') || (ch == 'L')) month = 7; } else if ((ch == 'a') || (ch == 'A')) month = 1; break; case 'F': case 'f': /* Feb */ month = 2; break; case 'M': case 'm': /* May, Mar */ ch = *date++; if ((ch == 'a') || (ch == 'A')) { ch = *date++; if ((ch == 'y') || (ch == 'Y')) month = 5; else if ((ch == 'r') || (ch == 'R')) month = 3; } break; case 'A': case 'a': /* Apr, Aug */ ch = *date++; if ((ch == 'p') || (ch == 'P')) month = 4; else if ((ch == 'u') || (ch == 'U')) month = 8; break; case 'S': case 's': /* Sep */ month = 9; break; case 'O': case 'o': /* Oct */ month = 10; break; case 'N': case 'n': /* Nov */ month = 11; break; case 'D': case 'd': /* Dec */ month = 12; break; } if (month == 0) return 0; month--; /* skip past month onto year. */ while (isalpha (*date)) date++; date = slrn_skip_whitespace (date); year = 0; if (*date == '9') year = 19; while (ch = *date, isdigit (ch)) { year = year * 10 + (long) (ch - '0'); date++; } date = slrn_skip_whitespace (date); /* Now parse hh:mm:ss */ hours = 0; while (ch = *date, isdigit (ch)) { hours = hours * 10 + (long) (ch - '0'); date++; } if ((ch != ':') || (hours >= 24)) return 0; date++; minutes = 0; while (ch = *date, isdigit (ch)) { minutes = minutes * 10 + (long) (ch - '0'); date++; } if (minutes >= 60) return 0; /* Seconds may not be present */ seconds = 0; if (ch == ':') { date++; while (ch = *date, isdigit (ch)) { seconds = seconds * 10 + (long) (ch - '0'); date++; } if (seconds >= 60) return 0; } /* Now timezone */ date = slrn_skip_whitespace (date); sign = 1; if (*date == '+') date++; else if (*date == '-') { sign = -1; date++; } tz = 0; while (ch = *date, isdigit(ch)) { tz = tz * 10 + (long) (ch - '0'); date++; } tz = sign * tz; date = slrn_skip_whitespace (date); if (isalpha (*date)) { sign = 1; if ((*date != 'G') && (*date != 'M') && (*date != 'T')) tz = parse_timezone (date); } /* Compute the number of days since beginning of year. */ day = 31 * month + day; if (month > 1) { day -= (month * 4 + 27)/10; if (IS_LEAP_YEAR(year)) day++; } /* add that to number of days since beginning of time */ year -= THE_YEAR_0; day += year * 365 + year / 4; if ((year % 4) == 1) day++; /* Adjust hours for timezone */ hours -= tz / 100; minutes -= tz % 100; /* ?? */ /* Now convert to secs */ seconds += 60L * (minutes + 60L * (hours + 24L * day)); return seconds; }