BinaryFunctions.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.commons.imaging.common;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.nio.ByteOrder;
import java.util.logging.Logger;
import org.apache.commons.imaging.ImagingException;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.RandomAccessFiles;
/**
* Convenience methods for various binary and I/O operations.
*/
public final class BinaryFunctions {
private static final Logger LOGGER = Logger.getLogger(BinaryFunctions.class.getName());
public static int charsToQuad(final char c1, final char c2, final char c3, final char c4) {
return (0xff & c1) << 24 | (0xff & c2) << 16 | (0xff & c3) << 8 | (0xff & c4) << 0;
}
public static boolean compareBytes(final byte[] a, final int aStart, final byte[] b, final int bStart, final int length) {
if (a.length < aStart + length) {
return false;
}
if (b.length < bStart + length) {
return false;
}
for (int i = 0; i < length; i++) {
if (a[aStart + i] != b[bStart + i]) {
return false;
}
}
return true;
}
public static int findNull(final byte[] src, final int start, final String message) throws ImagingException {
for (int i = start; i < src.length; i++) {
if (src[i] == 0) {
return i;
}
}
throw new ImagingException(message);
}
public static int findNull(final byte[] src, final String message) throws ImagingException {
return findNull(src, 0, message);
}
public static byte[] getBytes(final RandomAccessFile raf, final long pos, final int length, final String exception) throws IOException {
if (length < 0) {
throw new IOException(String.format("%s, invalid length: %d", exception, length));
}
Allocator.checkByteArray(length);
return RandomAccessFiles.read(raf, pos, length);
}
public static byte[] head(final byte[] bytes, int count) {
if (count > bytes.length) {
count = bytes.length;
}
return slice(bytes, 0, count);
}
public static void logByteBits(final String msg, final byte i) {
LOGGER.finest(msg + ": '" + Integer.toBinaryString(0xff & i));
}
public static void logCharQuad(final String msg, final int i) {
LOGGER.finest(msg + ": '" + (char) (0xff & i >> 24) + (char) (0xff & i >> 16) + (char) (0xff & i >> 8) + (char) (0xff & i >> 0) + "'");
}
public static void printCharQuad(final PrintWriter pw, final String msg, final int i) {
pw.println(msg + ": '" + (char) (0xff & i >> 24) + (char) (0xff & i >> 16) + (char) (0xff & i >> 8) + (char) (0xff & i >> 0) + "'");
}
/**
* Convert a quad into a byte array.
*
* @param quad quad
* @return a byte array
*/
public static byte[] quadsToByteArray(final int quad) {
final byte[] arr = new byte[4];
arr[0] = (byte) (quad >> 24);
arr[1] = (byte) (quad >> 16);
arr[2] = (byte) (quad >> 8);
arr[3] = (byte) quad;
return arr;
}
public static int read2Bytes(final String name, final InputStream is, final String exception, final ByteOrder byteOrder) throws IOException {
final int byte0 = is.read();
final int byte1 = is.read();
if ((byte0 | byte1) < 0) {
throw new IOException(exception);
}
final int result;
if (byteOrder == ByteOrder.BIG_ENDIAN) {
result = byte0 << 8 | byte1;
} else {
result = byte1 << 8 | byte0;
}
return result;
}
public static int read3Bytes(final String name, final InputStream is, final String exception, final ByteOrder byteOrder) throws IOException {
final int byte0 = is.read();
final int byte1 = is.read();
final int byte2 = is.read();
if ((byte0 | byte1 | byte2) < 0) {
throw new IOException(exception);
}
final int result;
if (byteOrder == ByteOrder.BIG_ENDIAN) {
result = byte0 << 16 | byte1 << 8 | byte2 << 0;
} else {
result = byte2 << 16 | byte1 << 8 | byte0 << 0;
}
return result;
}
public static int read4Bytes(final String name, final InputStream is, final String exception, final ByteOrder byteOrder) throws IOException {
final int byte0 = is.read();
final int byte1 = is.read();
final int byte2 = is.read();
final int byte3 = is.read();
if ((byte0 | byte1 | byte2 | byte3) < 0) {
throw new IOException(exception);
}
final int result;
if (byteOrder == ByteOrder.BIG_ENDIAN) {
result = byte0 << 24 | byte1 << 16 | byte2 << 8 | byte3 << 0;
} else {
result = byte3 << 24 | byte2 << 16 | byte1 << 8 | byte0 << 0;
}
return result;
}
/**
* Read eight bytes from the specified input stream, adjust for byte order, and return a long integer.
*
* @param name a descriptive identifier used for diagnostic purposes
* @param is a valid input stream
* @param exception application-defined message to be used for constructing an exception if an error condition is triggered.
* @param byteOrder the order in which the InputStream marshals data
* @return a long integer interpreted from next 8 bytes in the InputStream
* @throws IOException in the event of a non-recoverable error, such as an attempt to read past the end of file.
*/
public static long read8Bytes(final String name, final InputStream is, final String exception, final ByteOrder byteOrder) throws IOException {
final long byte0 = is.read();
final long byte1 = is.read();
final long byte2 = is.read();
final long byte3 = is.read();
final long byte4 = is.read();
final long byte5 = is.read();
final long byte6 = is.read();
final long byte7 = is.read();
if ((byte0 | byte1 | byte2 | byte3 | byte4 | byte5 | byte6 | byte7) < 0) {
throw new IOException(exception);
}
final long result;
if (byteOrder == ByteOrder.BIG_ENDIAN) {
result = byte0 << 56 | byte1 << 48 | byte2 << 40 | byte3 << 32 | byte4 << 24 | byte5 << 16 | byte6 << 8 | byte7 << 0;
} else {
result = byte7 << 56 | byte6 << 48 | byte5 << 40 | byte4 << 32 | byte3 << 24 | byte2 << 16 | byte1 << 8 | byte0 << 0;
}
return result;
}
public static void readAndVerifyBytes(final InputStream is, final BinaryConstant expected, final String exception) throws ImagingException, IOException {
for (int i = 0; i < expected.size(); i++) {
final int data = is.read();
final byte b = (byte) (0xff & data);
if (data < 0) {
throw new ImagingException("Unexpected EOF.");
}
if (b != expected.get(i)) {
throw new ImagingException(exception);
}
}
}
public static void readAndVerifyBytes(final InputStream is, final byte[] expected, final String exception) throws ImagingException, IOException {
for (final byte element : expected) {
final int data = is.read();
final byte b = (byte) (0xff & data);
if (data < 0) {
throw new ImagingException("Unexpected EOF.");
}
if (b != element) {
throw new ImagingException(exception);
}
}
}
public static byte readByte(final String name, final InputStream is, final String exceptionMessage) throws IOException {
final int result = is.read();
if (result < 0) {
throw new IOException(exceptionMessage);
}
return (byte) (0xff & result);
}
public static byte[] readBytes(final InputStream is, final int count) throws IOException {
return readBytes("", is, count, "Unexpected EOF");
}
public static byte[] readBytes(final String name, final InputStream is, final int length) throws IOException {
return readBytes(name, is, length, name + " could not be read.");
}
public static byte[] readBytes(final String name, final InputStream is, final int length, final String exception) throws IOException {
try {
return IOUtils.toByteArray(is, Allocator.check(length));
} catch (final IOException e) {
throw new IOException(exception + ", name: " + name + ", length: " + length);
}
}
public static byte[] remainingBytes(final String name, final byte[] bytes, final int count) {
return slice(bytes, count, bytes.length - count);
}
/**
* Consumes the {@code InputStream} (without closing it) searching for a quad. It will stop either when the quad is found, or when there are no more bytes
* in the input stream.
*
* <p>
* Returns {@code true} if it found the quad, and {@code false} otherwise.
*
* @param quad a quad (the needle)
* @param bis an input stream (the haystack)
* @return {@code true} if it found the quad, and {@code false} otherwise
* @throws IOException if it fails to read from the given input stream
*/
public static boolean searchQuad(final int quad, final InputStream bis) throws IOException {
final byte[] needle = BinaryFunctions.quadsToByteArray(quad);
int b = -1;
int position = 0;
while ((b = bis.read()) != -1) {
if (needle[position] == b) {
position++;
if (position == needle.length) {
return true;
}
} else {
position = 0;
}
}
return false;
}
public static long skipBytes(final InputStream is, final long length) throws IOException {
return skipBytes(is, length, "Couldn't skip bytes");
}
public static long skipBytes(final InputStream is, final long length, final String exMessage) throws IOException {
try {
return IOUtils.skip(is, length);
} catch (final IOException e) {
throw new IOException(exMessage, e);
}
}
public static byte[] slice(final byte[] bytes, final int start, final int count) {
final byte[] result = Allocator.byteArray(count);
System.arraycopy(bytes, start, result, 0, count);
return result;
}
public static boolean startsWith(final byte[] buffer, final BinaryConstant search) {
if (buffer == null || buffer.length < search.size()) {
return false;
}
for (int i = 0; i < search.size(); i++) {
if (buffer[i] != search.get(i)) {
return false;
}
}
return true;
}
public static boolean startsWith(final byte[] buffer, final byte[] search) {
if (search == null) {
return false;
}
if (buffer == null) {
return false;
}
if (search.length > buffer.length) {
return false;
}
for (int i = 0; i < search.length; i++) {
if (search[i] != buffer[i]) {
return false;
}
}
return true;
}
private BinaryFunctions() {
}
}