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// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
package org.xbill.DNS;
/**
* Routines for parsing BIND-style TTL values. These values consist of
* numbers followed by 1 letter units of time (W - week, D - day, H - hour,
* M - minute, S - second).
*
* @author Brian Wellington
*/
public final class TTL {
public static final long MAX_VALUE = 0x7FFFFFFFL;
private
TTL() {}
static void
check(long i) {
if (i < 0 || i > MAX_VALUE)
throw new InvalidTTLException(i);
}
/**
* Parses a TTL-like value, which can either be expressed as a number or a
* BIND-style string with numbers and units.
* @param s The string representing the numeric value.
* @param clamp Whether to clamp values in the range [MAX_VALUE + 1, 2^32 -1]
* to MAX_VALUE. This should be donw for TTLs, but not other values which
* can be expressed in this format.
* @return The value as a number of seconds
* @throws NumberFormatException The string was not in a valid TTL format.
*/
public static long
parse(String s, boolean clamp) {
if (s == null || s.length() == 0 || !Character.isDigit(s.charAt(0)))
throw new NumberFormatException();
long value = 0;
long ttl = 0;
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
long oldvalue = value;
if (Character.isDigit(c)) {
value = (value * 10) + Character.getNumericValue(c);
if (value < oldvalue)
throw new NumberFormatException();
} else {
switch (Character.toUpperCase(c)) {
case 'W': value *= 7;
case 'D': value *= 24;
case 'H': value *= 60;
case 'M': value *= 60;
case 'S': break;
default: throw new NumberFormatException();
}
ttl += value;
value = 0;
if (ttl > 0xFFFFFFFFL)
throw new NumberFormatException();
}
}
if (ttl == 0)
ttl = value;
if (ttl > 0xFFFFFFFFL)
throw new NumberFormatException();
else if (ttl > MAX_VALUE && clamp)
ttl = MAX_VALUE;
return ttl;
}
/**
* Parses a TTL, which can either be expressed as a number or a BIND-style
* string with numbers and units.
* @param s The string representing the TTL
* @return The TTL as a number of seconds
* @throws NumberFormatException The string was not in a valid TTL format.
*/
public static long
parseTTL(String s) {
return parse(s, true);
}
public static String
format(long ttl) {
TTL.check(ttl);
StringBuffer sb = new StringBuffer();
long secs, mins, hours, days, weeks;
secs = ttl % 60;
ttl /= 60;
mins = ttl % 60;
ttl /= 60;
hours = ttl % 24;
ttl /= 24;
days = ttl % 7;
ttl /= 7;
weeks = ttl;
if (weeks > 0)
sb.append(weeks + "W");
if (days > 0)
sb.append(days + "D");
if (hours > 0)
sb.append(hours + "H");
if (mins > 0)
sb.append(mins + "M");
if (secs > 0 || (weeks == 0 && days == 0 && hours == 0 && mins == 0))
sb.append(secs + "S");
return sb.toString();
}
}
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