/*
* 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.
IOException;
import java.io.
InputStream;
import java.util.
ArrayList;
import java.util.
List;
/**
* A {@code SeekableInputStream} implementation that caches data in memory.
* <p/>
*
* @see FileCacheSeekableStream
*
* @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/MemoryCacheSeekableStream.java#3 $
*/
public final class
MemoryCacheSeekableStream extends
AbstractCachedSeekableStream {
/**
* Creates a {@code MemoryCacheSeekableStream}, reading from the given
* {@code InputStream}. Data will be cached in memory.
*
* @param pStream the {@code InputStream} to read from.
*/
public
MemoryCacheSeekableStream(final
InputStream pStream) {
super(
pStream, new
MemoryCache());
}
public final boolean
isCachedMemory() {
return true;
}
public final boolean
isCachedFile() {
return false;
}
final static class
MemoryCache extends
StreamCache {
final static int
BLOCK_SIZE = 1 << 13;
private final
List<byte[]>
cache = new
ArrayList<byte[]>();
private long
length;
private long
position;
private long
start;
private byte[]
getBlock() throws
IOException {
final long
currPos =
position -
start;
if (
currPos < 0) {
throw new
IOException("StreamCache flushed before read position");
}
long
index =
currPos /
BLOCK_SIZE;
if (
index >=
Integer.
MAX_VALUE) {
throw new
IOException("Memory cache max size exceeded");
}
if (
index >=
cache.
size()) {
try {
cache.
add(new byte[
BLOCK_SIZE]);
// System.out.println("Allocating new block, size: " + BLOCK_SIZE);
// System.out.println("New total size: " + cache.size() * BLOCK_SIZE + " (" + cache.size() + " blocks)");
}
catch (
OutOfMemoryError e) {
throw new
IOException("No more memory for cache: " +
cache.
size() *
BLOCK_SIZE);
}
}
//System.out.println("index: " + index);
return
cache.
get((int)
index);
}
public void
write(final int
pByte) throws
IOException {
byte[]
buffer =
getBlock();
int
idx = (int) (
position %
BLOCK_SIZE);
buffer[
idx] = (byte)
pByte;
position++;
if (
position >
length) {
length =
position;
}
}
// TODO: OptimizeMe!!!
@
Override
public void
write(final byte[]
pBuffer, final int
pOffset, final int
pLength) throws
IOException {
byte[]
buffer =
getBlock();
for (int
i = 0;
i <
pLength;
i++) {
int
index = (int)
position %
BLOCK_SIZE;
if (
index == 0) {
buffer =
getBlock();
}
buffer[
index] =
pBuffer[
pOffset +
i];
position++;
}
if (
position >
length) {
length =
position;
}
}
public int
read() throws
IOException {
if (
position >=
length) {
return -1;
}
byte[]
buffer =
getBlock();
int
idx = (int) (
position %
BLOCK_SIZE);
position++;
return
buffer[
idx] & 0xff;
}
// TODO: OptimizeMe!!!
@
Override
public int
read(final byte[]
pBytes, final int
pOffset, final int
pLength) throws
IOException {
if (
position >=
length) {
return -1;
}
byte[]
buffer =
getBlock();
int
bufferPos = (int) (
position %
BLOCK_SIZE);
// Find maxIdx and simplify test in for-loop
int
maxLen = (int)
Math.
min(
Math.
min(
pLength,
buffer.length -
bufferPos),
length -
position);
int
i;
//for (i = 0; i < pLength && i < buffer.length - idx && i < length - position; i++) {
for (
i = 0;
i <
maxLen;
i++) {
pBytes[
pOffset +
i] =
buffer[
bufferPos +
i];
}
position +=
i;
return
i;
}
public void
seek(final long
pPosition) throws
IOException {
if (
pPosition <
start) {
throw new
IOException("Seek before flush position");
}
position =
pPosition;
}
@
Override
public void
flush(final long
pPosition) {
int
firstPos = (int) (
pPosition /
BLOCK_SIZE) - 1;
for (int
i = 0;
i <
firstPos;
i++) {
cache.
remove(0);
}
start =
pPosition;
}
public long
getPosition() {
return
position;
}
}
}