| /* |
| * 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.compress.utils; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.OutputStream; |
| |
| /** |
| * Utility methods for reading and writing bytes. |
| * @since 1.14 |
| */ |
| public final class ByteUtils { |
| private ByteUtils() { /* no instances */ } |
| |
| /** |
| * Used to supply bytes. |
| * @since 1.14 |
| */ |
| public interface ByteSupplier { |
| /** |
| * The contract is similar to {@link InputStream#read()}, return |
| * the byte as an unsigned int, -1 if there are no more bytes. |
| * @return the supplied byte or -1 if there are no more bytes |
| * @throws IOException if supplying fails |
| */ |
| int getAsByte() throws IOException; |
| } |
| |
| /** |
| * Used to consume bytes. |
| * @since 1.14 |
| */ |
| public interface ByteConsumer { |
| /** |
| * The contract is similar to {@link OutputStream#write(int)}, |
| * consume the lower eight bytes of the int as a byte. |
| * @param b the byte to consume |
| * @throws IOException if consuming fails |
| */ |
| void accept(int b) throws IOException; |
| } |
| |
| /** |
| * Reads the given byte array as a little endian long. |
| * @param bytes the byte array to convert |
| * @return the number read |
| */ |
| public static long fromLittleEndian(final byte[] bytes) { |
| return fromLittleEndian(bytes, 0, bytes.length); |
| } |
| |
| /** |
| * Reads the given byte array as a little endian long. |
| * @param bytes the byte array to convert |
| * @param off the offset into the array that starts the value |
| * @param length the number of bytes representing the value |
| * @return the number read |
| * @throws IllegalArgumentException if len is bigger than eight |
| */ |
| public static long fromLittleEndian(final byte[] bytes, final int off, final int length) { |
| checkReadLength(length); |
| long l = 0; |
| for (int i = 0; i < length; i++) { |
| l |= (bytes[off + i] & 0xffL) << (8 * i); |
| } |
| return l; |
| } |
| |
| /** |
| * Reads the given number of bytes from the given stream as a little endian long. |
| * @param in the stream to read from |
| * @param length the number of bytes representing the value |
| * @return the number read |
| * @throws IllegalArgumentException if len is bigger than eight |
| * @throws IOException if reading fails or the stream doesn't |
| * contain the given number of bytes anymore |
| */ |
| public static long fromLittleEndian(final InputStream in, final int length) throws IOException { |
| // somewhat duplicates the ByteSupplier version in order to save the creation of a wrapper object |
| checkReadLength(length); |
| long l = 0; |
| for (int i = 0; i < length; i++) { |
| final long b = in.read(); |
| if (b == -1) { |
| throw new IOException("Premature end of data"); |
| } |
| l |= (b << (i * 8)); |
| } |
| return l; |
| } |
| |
| /** |
| * Reads the given number of bytes from the given supplier as a little endian long. |
| * |
| * <p>Typically used by our InputStreams that need to count the |
| * bytes read as well.</p> |
| * |
| * @param supplier the supplier for bytes |
| * @param length the number of bytes representing the value |
| * @return the number read |
| * @throws IllegalArgumentException if len is bigger than eight |
| * @throws IOException if the supplier fails or doesn't supply the |
| * given number of bytes anymore |
| */ |
| public static long fromLittleEndian(final ByteSupplier supplier, final int length) throws IOException { |
| checkReadLength(length); |
| long l = 0; |
| for (int i = 0; i < length; i++) { |
| final long b = supplier.getAsByte(); |
| if (b == -1) { |
| throw new IOException("Premature end of data"); |
| } |
| l |= (b << (i * 8)); |
| } |
| return l; |
| } |
| |
| /** |
| * Reads the given number of bytes from the given input as little endian long. |
| * @param in the input to read from |
| * @param length the number of bytes representing the value |
| * @return the number read |
| * @throws IllegalArgumentException if len is bigger than eight |
| * @throws IOException if reading fails or the stream doesn't |
| * contain the given number of bytes anymore |
| */ |
| public static long fromLittleEndian(final DataInput in, final int length) throws IOException { |
| // somewhat duplicates the ByteSupplier version in order to save the creation of a wrapper object |
| checkReadLength(length); |
| long l = 0; |
| for (int i = 0; i < length; i++) { |
| final long b = in.readUnsignedByte(); |
| l |= (b << (i * 8)); |
| } |
| return l; |
| } |
| |
| /** |
| * Inserts the given value into the array as a little endian |
| * sequence of the given length starting at the given offset. |
| * @param b the array to write into |
| * @param value the value to insert |
| * @param off the offset into the array that receives the first byte |
| * @param length the number of bytes to use to represent the value |
| */ |
| public static void toLittleEndian(final byte[] b, final long value, final int off, final int length) { |
| long num = value; |
| for (int i = 0; i < length; i++) { |
| b[off + i] = (byte) (num & 0xff); |
| num >>= 8; |
| } |
| } |
| |
| /** |
| * Writes the given value to the given stream as a little endian |
| * array of the given length. |
| * @param out the stream to write to |
| * @param value the value to write |
| * @param length the number of bytes to use to represent the value |
| * @throws IOException if writing fails |
| */ |
| public static void toLittleEndian(final OutputStream out, final long value, final int length) |
| throws IOException { |
| // somewhat duplicates the ByteConsumer version in order to save the creation of a wrapper object |
| long num = value; |
| for (int i = 0; i < length; i++) { |
| out.write((int) (num & 0xff)); |
| num >>= 8; |
| } |
| } |
| |
| /** |
| * Provides the given value to the given consumer as a little endian |
| * sequence of the given length. |
| * @param consumer the consumer to provide the bytes to |
| * @param value the value to provide |
| * @param length the number of bytes to use to represent the value |
| * @throws IOException if writing fails |
| */ |
| public static void toLittleEndian(final ByteConsumer consumer, final long value, final int length) |
| throws IOException { |
| long num = value; |
| for (int i = 0; i < length; i++) { |
| consumer.accept((int) (num & 0xff)); |
| num >>= 8; |
| } |
| } |
| |
| /** |
| * Writes the given value to the given stream as a little endian |
| * array of the given length. |
| * @param out the output to write to |
| * @param value the value to write |
| * @param length the number of bytes to use to represent the value |
| * @throws IOException if writing fails |
| */ |
| public static void toLittleEndian(final DataOutput out, final long value, final int length) |
| throws IOException { |
| // somewhat duplicates the ByteConsumer version in order to save the creation of a wrapper object |
| long num = value; |
| for (int i = 0; i < length; i++) { |
| out.write((int) (num & 0xff)); |
| num >>= 8; |
| } |
| } |
| |
| /** |
| * {@link ByteSupplier} based on {@link InputStream}. |
| * @since 1.14 |
| */ |
| public static class InputStreamByteSupplier implements ByteSupplier { |
| private final InputStream is; |
| public InputStreamByteSupplier(final InputStream is) { |
| this.is = is; |
| } |
| @Override |
| public int getAsByte() throws IOException { |
| return is.read(); |
| } |
| } |
| |
| /** |
| * {@link ByteConsumer} based on {@link OutputStream}. |
| * @since 1.14 |
| */ |
| public static class OutputStreamByteConsumer implements ByteConsumer { |
| private final OutputStream os; |
| public OutputStreamByteConsumer(final OutputStream os) { |
| this.os = os; |
| } |
| @Override |
| public void accept(final int b) throws IOException { |
| os.write(b); |
| } |
| } |
| |
| private static void checkReadLength(final int length) { |
| if (length > 8) { |
| throw new IllegalArgumentException("Can't read more than eight bytes into a long value"); |
| } |
| } |
| } |