src/main/java/org/apache/commons/compress/utils/IOUtils.java - platform/external/apache-commons-compress - Git at Google

 /*
  * 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.ByteArrayOutputStream;
 import java.io.Closeable;
 import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.nio.channels.ReadableByteChannel;

 /**
  * Utility functions
  * @Immutable (has mutable data but it is write-only)
  */
 public final class IOUtils {

     private static final int COPY_BUF_SIZE = 8024;
     private static final int SKIP_BUF_SIZE = 4096;

     // This buffer does not need to be synchronised because it is write only; the contents are ignored
     // Does not affect Immutability
     private static final byte[] SKIP_BUF = new byte[SKIP_BUF_SIZE];

     /** Private constructor to prevent instantiation of this utility class. */
     private IOUtils(){
     }

     /**
      * Copies the content of a InputStream into an OutputStream.
      * Uses a default buffer size of 8024 bytes.
      *
      * @param input
      *            the InputStream to copy
      * @param output
      *            the target Stream
      * @return the number of bytes copied
      * @throws IOException
      *             if an error occurs
      */
     public static long copy(final InputStream input, final OutputStream output) throws IOException {
         return copy(input, output, COPY_BUF_SIZE);
     }

     /**
      * Copies the content of a InputStream into an OutputStream
      *
      * @param input
      *            the InputStream to copy
      * @param output
      *            the target Stream
      * @param buffersize
      *            the buffer size to use, must be bigger than 0
      * @return the number of bytes copied
      * @throws IOException
      *             if an error occurs
      * @throws IllegalArgumentException
      *             if buffersize is smaller than or equal to 0
      */
     public static long copy(final InputStream input, final OutputStream output, final int buffersize) throws IOException {
         if (buffersize < 1) {
             throw new IllegalArgumentException("buffersize must be bigger than 0");
         }
         final byte[] buffer = new byte[buffersize];
         int n = 0;
         long count=0;
         while (-1 != (n = input.read(buffer))) {
             output.write(buffer, 0, n);
             count += n;
         }
         return count;
     }

     /**
      * Skips the given number of bytes by repeatedly invoking skip on
      * the given input stream if necessary.
      *
      * <p>In a case where the stream's skip() method returns 0 before
      * the requested number of bytes has been skip this implementation
      * will fall back to using the read() method.</p>
      *
      * <p>This method will only skip less than the requested number of
      * bytes if the end of the input stream has been reached.</p>
      *
      * @param input stream to skip bytes in
      * @param numToSkip the number of bytes to skip
      * @return the number of bytes actually skipped
      * @throws IOException on error
      */
     public static long skip(final InputStream input, long numToSkip) throws IOException {
         final long available = numToSkip;
         while (numToSkip > 0) {
             final long skipped = input.skip(numToSkip);
             if (skipped == 0) {
                 break;
             }
             numToSkip -= skipped;
         }

         while (numToSkip > 0) {
             final int read = readFully(input, SKIP_BUF, 0,
                                  (int) Math.min(numToSkip, SKIP_BUF_SIZE));
             if (read < 1) {
                 break;
             }
             numToSkip -= read;
         }
         return available - numToSkip;
     }

     /**
      * Reads as much from input as possible to fill the given array.
      *
      * <p>This method may invoke read repeatedly to fill the array and
      * only read less bytes than the length of the array if the end of
      * the stream has been reached.</p>
      *
      * @param input stream to read from
      * @param b buffer to fill
      * @return the number of bytes actually read
      * @throws IOException on error
      */
     public static int readFully(final InputStream input, final byte[] b) throws IOException {
         return readFully(input, b, 0, b.length);
     }

     /**
      * Reads as much from input as possible to fill the given array
      * with the given amount of bytes.
      *
      * <p>This method may invoke read repeatedly to read the bytes and
      * only read less bytes than the requested length if the end of
      * the stream has been reached.</p>
      *
      * @param input stream to read from
      * @param b buffer to fill
      * @param offset offset into the buffer to start filling at
      * @param len of bytes to read
      * @return the number of bytes actually read
      * @throws IOException
      *             if an I/O error has occurred
      */
     public static int readFully(final InputStream input, final byte[] b, final int offset, final int len)
         throws IOException {
         if (len < 0 || offset < 0 || len + offset > b.length) {
             throw new IndexOutOfBoundsException();
         }
         int count = 0, x = 0;
         while (count != len) {
             x = input.read(b, offset + count, len - count);
             if (x == -1) {
                 break;
             }
             count += x;
         }
         return count;
     }

     /**
      * Reads {@code b.remaining()} bytes from the given channel
      * starting at the current channel's position.
      *
      * <p>This method reads repeatedly from the channel until the
      * requested number of bytes are read. This method blocks until
      * the requested number of bytes are read, the end of the channel
      * is detected, or an exception is thrown.</p>
      *
      * @param channel the channel to read from
      * @param b the buffer into which the data is read.
      * @throws IOException - if an I/O error occurs.
      * @throws EOFException - if the channel reaches the end before reading all the bytes.
      */
     public static void readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException {
         final int expectedLength = b.remaining();
         int read = 0;
         while (read < expectedLength) {
             int readNow = channel.read(b);
             if (readNow <= 0) {
                 break;
             }
             read += readNow;
         }
         if (read < expectedLength) {
             throw new EOFException();
         }
     }

     // toByteArray(InputStream) copied from:
     // commons/proper/io/trunk/src/main/java/org/apache/commons/io/IOUtils.java?revision=1428941
     // January 8th, 2013
     //
     // Assuming our copy() works just as well as theirs!  :-)

     /**
      * Gets the contents of an <code>InputStream</code> as a <code>byte[]</code>.
      * <p>
      * This method buffers the input internally, so there is no need to use a
      * <code>BufferedInputStream</code>.
      *
      * @param input  the <code>InputStream</code> to read from
      * @return the requested byte array
      * @throws NullPointerException if the input is null
      * @throws IOException if an I/O error occurs
      * @since 1.5
      */
     public static byte[] toByteArray(final InputStream input) throws IOException {
         final ByteArrayOutputStream output = new ByteArrayOutputStream();
         copy(input, output);
         return output.toByteArray();
     }

     /**
      * Closes the given Closeable and swallows any IOException that may occur.
      * @param c Closeable to close, can be null
      * @since 1.7
      */
     public static void closeQuietly(final Closeable c) {
         if (c != null) {
             try {
                 c.close();
             } catch (final IOException ignored) { // NOPMD
             }
         }
     }
 }
	/*
	* 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.ByteArrayOutputStream;
	import java.io.Closeable;
	import java.io.EOFException;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.nio.ByteBuffer;
	import java.nio.channels.ReadableByteChannel;

	/**
	* Utility functions
	* @Immutable (has mutable data but it is write-only)
	*/
	public final class IOUtils {

	private static final int COPY_BUF_SIZE = 8024;
	private static final int SKIP_BUF_SIZE = 4096;

	// This buffer does not need to be synchronised because it is write only; the contents are ignored
	// Does not affect Immutability
	private static final byte[] SKIP_BUF = new byte[SKIP_BUF_SIZE];

	/** Private constructor to prevent instantiation of this utility class. */
	private IOUtils(){
	}

	/**
	* Copies the content of a InputStream into an OutputStream.
	* Uses a default buffer size of 8024 bytes.
	*
	* @param input
	* the InputStream to copy
	* @param output
	* the target Stream
	* @return the number of bytes copied
	* @throws IOException
	* if an error occurs
	*/
	public static long copy(final InputStream input, final OutputStream output) throws IOException {
	return copy(input, output, COPY_BUF_SIZE);
	}

	/**
	* Copies the content of a InputStream into an OutputStream
	*
	* @param input
	* the InputStream to copy
	* @param output
	* the target Stream
	* @param buffersize
	* the buffer size to use, must be bigger than 0
	* @return the number of bytes copied
	* @throws IOException
	* if an error occurs
	* @throws IllegalArgumentException
	* if buffersize is smaller than or equal to 0
	*/
	public static long copy(final InputStream input, final OutputStream output, final int buffersize) throws IOException {
	if (buffersize < 1) {
	throw new IllegalArgumentException("buffersize must be bigger than 0");
	}
	final byte[] buffer = new byte[buffersize];
	int n = 0;
	long count=0;
	while (-1 != (n = input.read(buffer))) {
	output.write(buffer, 0, n);
	count += n;
	}
	return count;
	}

	/**
	* Skips the given number of bytes by repeatedly invoking skip on
	* the given input stream if necessary.
	*
	* <p>In a case where the stream's skip() method returns 0 before
	* the requested number of bytes has been skip this implementation
	* will fall back to using the read() method.</p>
	*
	* <p>This method will only skip less than the requested number of
	* bytes if the end of the input stream has been reached.</p>
	*
	* @param input stream to skip bytes in
	* @param numToSkip the number of bytes to skip
	* @return the number of bytes actually skipped
	* @throws IOException on error
	*/
	public static long skip(final InputStream input, long numToSkip) throws IOException {
	final long available = numToSkip;
	while (numToSkip > 0) {
	final long skipped = input.skip(numToSkip);
	if (skipped == 0) {
	break;
	}
	numToSkip -= skipped;
	}

	while (numToSkip > 0) {
	final int read = readFully(input, SKIP_BUF, 0,
	(int) Math.min(numToSkip, SKIP_BUF_SIZE));
	if (read < 1) {
	break;
	}
	numToSkip -= read;
	}
	return available - numToSkip;
	}

	/**
	* Reads as much from input as possible to fill the given array.
	*
	* <p>This method may invoke read repeatedly to fill the array and
	* only read less bytes than the length of the array if the end of
	* the stream has been reached.</p>
	*
	* @param input stream to read from
	* @param b buffer to fill
	* @return the number of bytes actually read
	* @throws IOException on error
	*/
	public static int readFully(final InputStream input, final byte[] b) throws IOException {
	return readFully(input, b, 0, b.length);
	}

	/**
	* Reads as much from input as possible to fill the given array
	* with the given amount of bytes.
	*
	* <p>This method may invoke read repeatedly to read the bytes and
	* only read less bytes than the requested length if the end of
	* the stream has been reached.</p>
	*
	* @param input stream to read from
	* @param b buffer to fill
	* @param offset offset into the buffer to start filling at
	* @param len of bytes to read
	* @return the number of bytes actually read
	* @throws IOException
	* if an I/O error has occurred
	*/
	public static int readFully(final InputStream input, final byte[] b, final int offset, final int len)
	throws IOException {
	if (len < 0 \|\| offset < 0 \|\| len + offset > b.length) {
	throw new IndexOutOfBoundsException();
	}
	int count = 0, x = 0;
	while (count != len) {
	x = input.read(b, offset + count, len - count);
	if (x == -1) {
	break;
	}
	count += x;
	}
	return count;
	}

	/**
	* Reads {@code b.remaining()} bytes from the given channel
	* starting at the current channel's position.
	*
	* <p>This method reads repeatedly from the channel until the
	* requested number of bytes are read. This method blocks until
	* the requested number of bytes are read, the end of the channel
	* is detected, or an exception is thrown.</p>
	*
	* @param channel the channel to read from
	* @param b the buffer into which the data is read.
	* @throws IOException - if an I/O error occurs.
	* @throws EOFException - if the channel reaches the end before reading all the bytes.
	*/
	public static void readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException {
	final int expectedLength = b.remaining();
	int read = 0;
	while (read < expectedLength) {
	int readNow = channel.read(b);
	if (readNow <= 0) {
	break;
	}
	read += readNow;
	}
	if (read < expectedLength) {
	throw new EOFException();
	}
	}

	// toByteArray(InputStream) copied from:
	// commons/proper/io/trunk/src/main/java/org/apache/commons/io/IOUtils.java?revision=1428941
	// January 8th, 2013
	//
	// Assuming our copy() works just as well as theirs! :-)

	/**
	* Gets the contents of an <code>InputStream</code> as a <code>byte[]</code>.
	* <p>
	* This method buffers the input internally, so there is no need to use a
	* <code>BufferedInputStream</code>.
	*
	* @param input the <code>InputStream</code> to read from
	* @return the requested byte array
	* @throws NullPointerException if the input is null
	* @throws IOException if an I/O error occurs
	* @since 1.5
	*/
	public static byte[] toByteArray(final InputStream input) throws IOException {
	final ByteArrayOutputStream output = new ByteArrayOutputStream();
	copy(input, output);
	return output.toByteArray();
	}

	/**
	* Closes the given Closeable and swallows any IOException that may occur.
	* @param c Closeable to close, can be null
	* @since 1.7
	*/
	public static void closeQuietly(final Closeable c) {
	if (c != null) {
	try {
	c.close();
	} catch (final IOException ignored) { // NOPMD
	}
	}
	}
	}