com.twelvemonkeys.io.FileSeekableStream Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.io;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
/**
* A {@code SeekableInputStream} implementation that uses random access directly to a {@code File}.
* @see FileCacheSeekableStream
* @see MemoryCacheSeekableStream
* @see RandomAccessFile
*
* @author Harald Kuhr
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/io/FileSeekableStream.java#4 $
*/
public final class FileSeekableStream extends SeekableInputStream {
// TODO: Figure out why this class is SLOWER than FileCacheSeekableStream in
// my tests..?
final RandomAccessFile mRandomAccess;
/**
* Creates a {@code FileSeekableStream} that reads from the given
* {@code File}.
*
* @param pInput file to read from
* @throws FileNotFoundException if {@code pInput} does not exist
*/
public FileSeekableStream(final File pInput) throws FileNotFoundException {
this(new RandomAccessFile(pInput, "r"));
}
/**
* Creates a {@code FileSeekableStream} that reads from the given file.
* The {@code RandomAccessFile} needs only to be open in read
* ({@code "r"}) mode.
*
* @param pInput file to read from
*/
public FileSeekableStream(final RandomAccessFile pInput) {
mRandomAccess = pInput;
}
/// Seekable
public boolean isCached() {
return false;
}
public boolean isCachedFile() {
return false;
}
public boolean isCachedMemory() {
return false;
}
/// InputStream
@Override
public int available() throws IOException {
long length = mRandomAccess.length() - position;
return length > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) length;
}
public void closeImpl() throws IOException {
mRandomAccess.close();
}
public int read() throws IOException {
checkOpen();
int read = mRandomAccess.read();
if (read >= 0) {
position++;
}
return read;
}
@Override
public int read(byte pBytes[], int pOffset, int pLength) throws IOException {
checkOpen();
int read = mRandomAccess.read(pBytes, pOffset, pLength);
if (read > 0) {
position += read;
}
return read;
}
/**
* Does nothing, as we don't really do any caching here.
*
* @param pPosition the position to flush to
*/
protected void flushBeforeImpl(long pPosition) {
}
protected void seekImpl(long pPosition) throws IOException {
mRandomAccess.seek(pPosition);
}
}