/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.internal.http;
import android.text.format.Time;
import java.util.Calendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Helper for parsing an HTTP date.
*/
public final class HttpDateTime {
/*
* Regular expression for parsing HTTP-date.
*
* Wdy, DD Mon YYYY HH:MM:SS GMT
* RFC 822, updated by RFC 1123
*
* Weekday, DD-Mon-YY HH:MM:SS GMT
* RFC 850, obsoleted by RFC 1036
*
* Wdy Mon DD HH:MM:SS YYYY
* ANSI C's asctime() format
*
* with following variations
*
* Wdy, DD-Mon-YYYY HH:MM:SS GMT
* Wdy, (SP)D Mon YYYY HH:MM:SS GMT
* Wdy,DD Mon YYYY HH:MM:SS GMT
* Wdy, DD-Mon-YY HH:MM:SS GMT
* Wdy, DD Mon YYYY HH:MM:SS -HHMM
* Wdy, DD Mon YYYY HH:MM:SS
* Wdy Mon (SP)D HH:MM:SS YYYY
* Wdy Mon DD HH:MM:SS YYYY GMT
*
* HH can be H if the first digit is zero.
*
* Mon can be the full name of the month.
*/
private static final String HTTP_DATE_RFC_REGEXP =
"([0-9]{1,2})[- ]([A-Za-z]{3,9})[- ]([0-9]{2,4})[ ]"
+ "([0-9]{1,2}:[0-9][0-9]:[0-9][0-9])";
private static final String HTTP_DATE_ANSIC_REGEXP =
"[ ]([A-Za-z]{3,9})[ ]+([0-9]{1,2})[ ]"
+ "([0-9]{1,2}:[0-9][0-9]:[0-9][0-9])[ ]([0-9]{2,4})";
/**
* The compiled version of the HTTP-date regular expressions.
*/
private static final Pattern HTTP_DATE_RFC_PATTERN =
Pattern.compile(HTTP_DATE_RFC_REGEXP);
private static final Pattern HTTP_DATE_ANSIC_PATTERN =
Pattern.compile(HTTP_DATE_ANSIC_REGEXP);
private static class TimeOfDay {
TimeOfDay(int h, int m, int s) {
this.hour = h;
this.minute = m;
this.second = s;
}
int hour;
int minute;
int second;
}
public static long parse(String timeString)
throws IllegalArgumentException {
int date = 1;
int month = Calendar.JANUARY;
int year = 1970;
TimeOfDay timeOfDay;
Matcher rfcMatcher = HTTP_DATE_RFC_PATTERN.matcher(timeString);
if (rfcMatcher.find()) {
date = getDate(rfcMatcher.group(1));
month = getMonth(rfcMatcher.group(2));
year = getYear(rfcMatcher.group(3));
timeOfDay = getTime(rfcMatcher.group(4));
} else {
Matcher ansicMatcher = HTTP_DATE_ANSIC_PATTERN.matcher(timeString);
if (ansicMatcher.find()) {
month = getMonth(ansicMatcher.group(1));
date = getDate(ansicMatcher.group(2));
timeOfDay = getTime(ansicMatcher.group(3));
year = getYear(ansicMatcher.group(4));
} else {
throw new IllegalArgumentException();
}
}
// FIXME: Y2038 BUG!
if (year >= 2038) {
year = 2038;
month = Calendar.JANUARY;
date = 1;
}
Time time = new Time(Time.TIMEZONE_UTC);
time.set(timeOfDay.second, timeOfDay.minute, timeOfDay.hour, date,
month, year);
return time.toMillis(false /* use isDst */);
}
private static int getDate(String dateString) {
if (dateString.length() == 2) {
return (dateString.charAt(0) - '0') * 10
+ (dateString.charAt(1) - '0');
} else {
return (dateString.charAt(0) - '0');
}
}
/*
* jan = 9 + 0 + 13 = 22
* feb = 5 + 4 + 1 = 10
* mar = 12 + 0 + 17 = 29
* apr = 0 + 15 + 17 = 32
* may = 12 + 0 + 24 = 36
* jun = 9 + 20 + 13 = 42
* jul = 9 + 20 + 11 = 40
* aug = 0 + 20 + 6 = 26
* sep = 18 + 4 + 15 = 37
* oct = 14 + 2 + 19 = 35
* nov = 13 + 14 + 21 = 48
* dec = 3 + 4 + 2 = 9
*/
private static int getMonth(String monthString) {
int hash = Character.toLowerCase(monthString.charAt(0)) +
Character.toLowerCase(monthString.charAt(1)) +
Character.toLowerCase(monthString.charAt(2)) - 3 * 'a';
switch (hash) {
case 22:
return Calendar.JANUARY;
case 10:
return Calendar.FEBRUARY;
case 29:
return Calendar.MARCH;
case 32:
return Calendar.APRIL;
case 36:
return Calendar.MAY;
case 42:
return Calendar.JUNE;
case 40:
return Calendar.JULY;
case 26:
return Calendar.AUGUST;
case 37:
return Calendar.SEPTEMBER;
case 35:
return Calendar.OCTOBER;
case 48:
return Calendar.NOVEMBER;
case 9:
return Calendar.DECEMBER;
default:
throw new IllegalArgumentException();
}
}
private static int getYear(String yearString) {
if (yearString.length() == 2) {
int year = (yearString.charAt(0) - '0') * 10
+ (yearString.charAt(1) - '0');
if (year >= 70) {
return year + 1900;
} else {
return year + 2000;
}
} else if (yearString.length() == 3) {
// According to RFC 2822, three digit years should be added to 1900.
int year = (yearString.charAt(0) - '0') * 100
+ (yearString.charAt(1) - '0') * 10
+ (yearString.charAt(2) - '0');
return year + 1900;
} else if (yearString.length() == 4) {
return (yearString.charAt(0) - '0') * 1000
+ (yearString.charAt(1) - '0') * 100
+ (yearString.charAt(2) - '0') * 10
+ (yearString.charAt(3) - '0');
} else {
return 1970;
}
}
private static TimeOfDay getTime(String timeString) {
// HH might be H
int i = 0;
int hour = timeString.charAt(i++) - '0';
if (timeString.charAt(i) != ':')
hour = hour * 10 + (timeString.charAt(i++) - '0');
// Skip ':'
i++;
int minute = (timeString.charAt(i++) - '0') * 10
+ (timeString.charAt(i++) - '0');
// Skip ':'
i++;
int second = (timeString.charAt(i++) - '0') * 10
+ (timeString.charAt(i++) - '0');
return new TimeOfDay(hour, minute, second);
}
}