This repository has been archived on 2023-08-20. You can view files and clone it, but cannot push or open issues or pull requests.
yap-6.3/packages/clib/maildrop/rfc822/rfc822_parsedt.c
Vítor Santos Costa 40febfdf9b clib package
2010-06-17 00:40:25 +01:00

244 lines
4.5 KiB
C

/*
** Copyright 1998 - 1999 Double Precision, Inc.
** See COPYING for distribution information.
*/
/*
** $Id$
*/
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
/*
** time_t rfc822_parsedate(const char *p)
**
** p - contents of the Date: header, attempt to parse it into a time_t.
**
** returns - time_t, or 0 if the date cannot be parsed
*/
static unsigned parsedig(const char **p)
{
unsigned i=0;
while (isdigit((int)(unsigned char)**p))
{
i=i*10 + **p - '0';
++*p;
}
return (i);
}
static const char * const weekdays[7]={
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
} ;
static const char * const mnames[13]={
"Jan", "Feb", "Mar", "Apr",
"May", "Jun", "Jul", "Aug",
"Sep", "Oct", "Nov", "Dec", NULL};
#define leap(y) ( \
((y) % 400) == 0 || \
(((y) % 4) == 0 && (y) % 100) )
static unsigned mlength[]={31,28,31,30,31,30,31,31,30,31,30,31};
#define mdays(m,y) ( (m) != 2 ? mlength[(m)-1] : leap(y) ? 29:28)
static const char * const zonenames[] = {
"UT","GMT",
"EST","EDT",
"CST","CDT",
"MST","MDT",
"PST","PDT",
"Z",
"A", "B", "C", "D", "E", "F", "G", "H", "I", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y",
NULL};
#define ZH(n) ( (n) * 60 * 60 )
static int zoneoffset[] = {
0, 0,
ZH(-5), ZH(-4),
ZH(-6), ZH(-5),
ZH(-7), ZH(-6),
ZH(-8), ZH(-7),
0,
ZH(-1), ZH(-2), ZH(-3), ZH(-4), ZH(-5), ZH(-6), ZH(-7), ZH(-8), ZH(-9), ZH(-10), ZH(-11), ZH(-12),
ZH(1), ZH(2), ZH(3), ZH(4), ZH(5), ZH(6), ZH(7), ZH(8), ZH(9), ZH(10), ZH(11), ZH(12) };
static unsigned parsekey(const char **mon, const char * const *ary)
{
unsigned m, j;
for (m=0; ary[m]; m++)
{
for (j=0; ary[m][j]; j++)
if (tolower(ary[m][j]) != tolower((*mon)[j]))
break;
if (!ary[m][j])
{
*mon += j;
return (m+1);
}
}
return (0);
}
static int parsetime(const char **t)
{
unsigned h,m,s=0;
if (!isdigit((int)(unsigned char)**t)) return (-1);
h=parsedig(t);
if (h > 23) return (-1);
if (**t != ':') return (-1);
++*t;
if (!isdigit((int)(unsigned char)**t)) return (-1);
m=parsedig(t);
if (**t == ':')
{
++*t;
if (!isdigit((int)(unsigned char)**t)) return (-1);
s=parsedig(t);
}
if (m > 59 || s > 59) return (-1);
return (h * 60 * 60 + m * 60 + s);
}
time_t rfc822_parsedt(const char *rfcdt)
{
unsigned day=0, mon=0, year;
int secs;
int offset;
time_t t;
unsigned y;
/* Ignore day of the week. Tolerate "Tue, 25 Feb 1997 ... "
** without the comma. Tolerate "Feb 25 1997 ...".
*/
while (!day || !mon)
{
if (!*rfcdt) return (0);
if (isalpha((int)(unsigned char)*rfcdt))
{
if (mon) return (0);
mon=parsekey(&rfcdt, mnames);
if (!mon)
while (*rfcdt && isalpha((int)(unsigned char)*rfcdt))
++rfcdt;
continue;
}
if (isdigit((int)(unsigned char)*rfcdt))
{
if (day) return (0);
day=parsedig(&rfcdt);
if (!day) return (0);
continue;
}
++rfcdt;
}
while (*rfcdt && isspace((int)(unsigned char)*rfcdt))
++rfcdt;
if (!isdigit((int)(unsigned char)*rfcdt)) return (0);
year=parsedig(&rfcdt);
if (year < 70) year += 2000;
if (year < 100) year += 1900;
while (*rfcdt && isspace((int)(unsigned char)*rfcdt))
++rfcdt;
if (day == 0 || mon == 0 || mon > 12 || day > mdays(mon,year))
return (0);
secs=parsetime(&rfcdt);
if (secs < 0) return (0);
offset=0;
/* RFC822 sez no parenthesis, but I've seen (EST) */
while ( *rfcdt )
{
if (isalnum((int)(unsigned char)*rfcdt) || *rfcdt == '+' || *rfcdt == '-')
break;
++rfcdt;
}
if (isalpha((int)(unsigned char)*rfcdt))
{
int n=parsekey(&rfcdt, zonenames);
if (n > 0) offset= zoneoffset[n-1];
}
else
{
int sign=1;
unsigned n;
switch (*rfcdt) {
case '-':
sign= -1;
case '+':
++rfcdt;
}
if (isdigit((int)(unsigned char)*rfcdt))
{
n=parsedig(&rfcdt);
if (n > 2359 || (n % 100) > 59) n=0;
offset = sign * ( (n % 100) * 60 + n / 100 * 60 * 60);
}
}
if (year < 1970) return (0);
t=0;
for (y=1970; y<year; y++)
{
if ( leap(y) )
{
if (year-y >= 4)
{
y += 3;
t += ( 365*3+366 ) * 24 * 60 * 60;
continue;
}
t += 24 * 60 * 60;
}
t += 365 * 24 * 60 * 60;
}
for (y=1; y < mon; y++)
t += mdays(y, year) * 24 * 60 * 60;
return ( t + (day-1) * 24 * 60 * 60 + secs - offset );
}
const char *rfc822_mkdt(time_t t)
{
static char buf[80];
struct tm *tmptr=gmtime(&t);
buf[0]=0;
if (tmptr)
{
sprintf(buf, "%s, %02d %s %04d %02d:%02d:%02d GMT",
weekdays[tmptr->tm_wday],
tmptr->tm_mday,
mnames[tmptr->tm_mon],
tmptr->tm_year + 1900,
tmptr->tm_hour,
tmptr->tm_min,
tmptr->tm_sec);
}
return (buf);
}