/*
* 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}.
* <p/>
* @see FileCacheSeekableStream
* @see MemoryCacheSeekableStream
* @see RandomAccessFile
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @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);
}
}