org.archive.io.Endian Maven / Gradle / Ivy
/*
* This file is part of the Heritrix web crawler (crawler.archive.org).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA licenses this file to You 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 org.archive.io;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
/**
* Reads integers stored in big or little endian streams.
*
* @author pjack
*/
public class Endian {
/**
* Static utility class.
*/
private Endian() {
}
/**
* Reads the next little-endian unsigned 16 bit integer from the
* given stream.
*
* @param input the input stream to read from
* @return the next 16-bit little-endian integer
* @throws IOException if an IO error occurs
*/
public static char littleChar(InputStream input) throws IOException {
int lo = input.read();
if (lo < 0) {
throw new EOFException();
}
int hi = input.read();
if (hi < 0) {
throw new EOFException();
}
return (char)((hi << 8) | lo);
}
/**
* Reads the next little-endian signed 16-bit integer from the
* given stream.
*
* @param input the input stream to read from
* @return the next 16-bit little-endian integer
* @throws IOException if an IO error occurs
*/
public static short littleShort(InputStream input) throws IOException {
return (short)littleChar(input);
}
/**
* Reads the next little-endian signed 32-bit integer from the
* given stream.
*
* @param input the input stream to read from
* @return the next 32-bit little-endian integer
* @throws IOException if an IO error occurs
*/
public static int littleInt(InputStream input) throws IOException {
char lo = littleChar(input);
char hi = littleChar(input);
return (hi << 16) | lo;
}
/**
* Reads the next big-endian unsigned 16 bit integer from the
* given stream.
*
* @param input the input stream to read from
* @return the next 16-bit big-endian integer
* @throws IOException if an IO error occurs
*/
public static char bigChar(InputStream input) throws IOException {
int hi = input.read();
if (hi < 0) {
throw new EOFException();
}
int lo = input.read();
if (lo < 0) {
throw new EOFException();
}
return (char)((hi << 8) | lo);
}
/**
* Reads the next big-endian signed 32-bit integer from the
* given stream.
*
* @param input the input stream to read from
* @return the next 32-bit big-endian integer
* @throws IOException if an IO error occurs
*/
public static int bigInt(InputStream input) throws IOException {
char hi = bigChar(input);
char lo = bigChar(input);
return (hi << 16) | lo;
}
}