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using System;
using System.Globalization;
namespace System.Web.Util
{
internal static class HttpDate
{
static readonly int[] s_tensDigit = new int[10] { 0, 10, 20, 30, 40, 50, 60, 70, 80, 90 };
/*++
Converts a 2 character string to integer
Arguments:
s String to convert
Returns:
numeric equivalent, 0 on failure.
--*/
static int atoi2(string s, int startIndex)
{
try {
int tens = s[0 + startIndex] - '0';
int ones = s[1 + startIndex] - '0';
return s_tensDigit[tens] + ones;
}
catch {
throw new FormatException(SR.GetString(SR.Atio2BadString, s, startIndex));
}
}
static readonly string[] s_days = new string [7] {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static readonly string[] s_months = new string[12] {
"Jan", "Feb", "Mar", "Apr",
"May", "Jun", "Jul", "Aug",
"Sep", "Oct", "Nov", "Dec"
};
// Custom table for make_month() for mapping "Apr" to 4
static readonly sbyte[] s_monthIndexTable = new sbyte[64] {
-1, (sbyte)'A', 2, 12, -1, -1, -1, 8, // A to G
-1, -1, -1, -1, 7, -1, (sbyte)'N', -1, // H to O
9, -1, (sbyte)'R', -1, 10, -1, 11, -1, // P to W
-1, 5, -1, -1, -1, -1, -1, -1, // X to Z
-1, (sbyte)'A', 2, 12, -1, -1, -1, 8, // a to g
-1, -1, -1, -1, 7, -1, (sbyte)'N', -1, // h to o
9, -1, (sbyte)'R', -1, 10, -1, 11, -1, // p to w
-1, 5, -1, -1, -1, -1, -1, -1 // x to z
};
static int make_month(string s, int startIndex)
{
int i;
sbyte monthIndex;
string monthString;
//
// use the third character as the index
//
i = ((int) s[2 + startIndex] - 0x40) & 0x3F;
monthIndex = s_monthIndexTable[i];
if ( monthIndex >= 13 ) {
//
// ok, we need to look at the second character
//
if ( monthIndex == (sbyte) 'N' ) {
//
// we got an N which we need to resolve further
//
//
// if s[1] is 'u' then Jun, if 'a' then Jan
//
if ( s_monthIndexTable[(s[1 + startIndex]-0x40) & 0x3f] == (sbyte) 'A' ) {
monthIndex = 1;
} else {
monthIndex = 6;
}
} else if ( monthIndex == (sbyte) 'R' ) {
//
// if s[1] is 'a' then Microsoft, if 'p' then April
//
if ( s_monthIndexTable[(s[1 + startIndex]-0x40) & 0x3f] == (sbyte) 'A' ) {
monthIndex = 3;
} else {
monthIndex = 4;
}
} else {
throw new FormatException(SR.GetString(SR.MakeMonthBadString, s, startIndex));
}
}
monthString = s_months[monthIndex-1];
if ( (s[0 + startIndex] == monthString[0]) &&
(s[1 + startIndex] == monthString[1]) &&
(s[2 + startIndex] == monthString[2]) ) {
return(monthIndex);
} else if ( ((Char.ToUpper(s[0 + startIndex], CultureInfo.InvariantCulture)) == monthString[0]) &&
((Char.ToLower(s[1 + startIndex], CultureInfo.InvariantCulture)) == monthString[1]) &&
((Char.ToLower(s[2 + startIndex], CultureInfo.InvariantCulture)) == monthString[2]) ) {
return monthIndex;
}
throw new FormatException(SR.GetString(SR.MakeMonthBadString, s, startIndex));
} // make_month
/*++
Converts a string representation of a GMT time (three different
varieties) to an NT representation of a file time.
We handle the following variations:
Sun, 06 Nov 1994 08:49:37 GMT (RFC 822 updated by RFC 1123)
Sunday, 06-Nov-94 08:49:37 GMT (RFC 850)
Sun Nov 06 08:49:37 1994 (ANSI C's asctime() format
Arguments:
time String representation of time field
Returns:
TRUE on success and FALSE on failure.
History:
Johnl 24-Jan-1995 Modified from WWW library
--*/
static internal DateTime UtcParse(string time)
{
int i;
int year, month, day, hour, minute, second;
if (time == null) {
throw new ArgumentNullException("time");
}
if ((i = time.IndexOf(',')) != -1) {
//
// Thursday, 10-Jun-93 01:29:59 GMT
// or: Thu, 10 Jan 1993 01:29:59 GMT */
//
int length = time.Length - i;
while (--length > 0 && time[++i] == ' ') ;
if (time[i+2] == '-' ) { /* First format */
if (length < 18) {
throw new FormatException(SR.GetString(SR.UtilParseDateTimeBad, time));
}
day = atoi2(time, i);
month = make_month(time, i + 3);
year = atoi2(time, i + 7);
if ( year < 50 ) {
year += 2000;
} else {
year += 1900;
}
hour = atoi2(time, i + 10);
minute = atoi2(time, i + 13);
second = atoi2(time, i +16);
} else { /* Second format */
if (length < 20) {
throw new FormatException(SR.GetString(SR.UtilParseDateTimeBad, time));
}
day = atoi2(time, i);
month = make_month(time, i + 3);
year = atoi2(time, i + 7) * 100 + atoi2(time, i + 9);
hour = atoi2(time, i + 12);
minute = atoi2(time, i + 15);
second = atoi2(time, i + 18);
}
} else { /* Try the other format: Wed Jun 09 01:29:59 1993 GMT */
i = -1;
int length = time.Length + 1;
while (--length > 0 && time[++i] == ' ');
if (length < 24) {
throw new FormatException(SR.GetString(SR.UtilParseDateTimeBad, time));
}
day = atoi2(time, i + 8);
month = make_month(time, i + 4);
year = atoi2(time, i + 20) * 100 + atoi2(time, i + 22);
hour = atoi2(time, i + 11);
minute = atoi2(time, i + 14);
second = atoi2(time, i + 17);
}
return new DateTime(year, month, day, hour, minute, second, DateTimeKind.Utc);
}
}
}
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