/*
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
package com.facebook.imageutils;
import java.io.IOException;
import java.io.InputStream;
/**
* Util for processing Stream.
*/
class StreamProcessor {
/**
* Consumes up to 4 bytes and returns them as int (taking into account endianess).
* Throws exception if specified number of bytes cannot be consumed.
* @param is the input stream to read bytes from
* @param numBytes the number of bytes to read
* @param isLittleEndian whether the bytes should be interpreted in little or big endian format
* @return packed int read from input stream and constructed according to endianess
*/
public static int readPackedInt(InputStream is, int numBytes, boolean isLittleEndian)
throws IOException {
int value = 0;
for (int i = 0; i < numBytes; i++) {
int b = is.read();
if (b == -1) {
throw new IOException("no more bytes");
}
if (isLittleEndian) {
value |= (b & 0xFF) << (i * 8);
} else {
value = (value << 8) | (b & 0xFF);
}
}
return value;
}
}