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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.compress;
import org.apache.lucene.store.IndexInput;
import org.elasticsearch.common.util.BigArrays;
import org.elasticsearch.common.util.LongArray;
import java.io.EOFException;
import java.io.IOException;
/**
* @deprecated Used only for backward comp. to read old compressed files, since we now use codec based compression
*/
@Deprecated
public abstract class CompressedIndexInput<T extends CompressorContext> extends IndexInput {
private IndexInput in;
protected final T context;
private int version;
private long totalUncompressedLength;
private LongArray offsets;
private boolean closed;
protected byte[] uncompressed;
protected int uncompressedLength;
private int position = 0;
private int valid = 0;
private int currentOffsetIdx;
private long currentUncompressedChunkPointer;
public CompressedIndexInput(IndexInput in, T context) throws IOException {
super("compressed(" + in.toString() + ")");
this.in = in;
this.context = context;
readHeader(in);
this.version = in.readInt();
long metaDataPosition = in.readLong();
long headerLength = in.getFilePointer();
in.seek(metaDataPosition);
this.totalUncompressedLength = in.readVLong();
int size = in.readVInt();
offsets = BigArrays.newLongArray(size);
for (int i = 0; i < size; i++) {
offsets.set(i, in.readVLong());
}
this.currentOffsetIdx = -1;
this.currentUncompressedChunkPointer = 0;
in.seek(headerLength);
}
/**
* Method is overridden to report number of bytes that can now be read
* from decoded data buffer, without reading bytes from the underlying
* stream.
* Never throws an exception; returns number of bytes available without
* further reads from underlying source; -1 if stream has been closed, or
* 0 if an actual read (and possible blocking) is needed to find out.
*/
public int available() throws IOException {
// if closed, return -1;
if (closed) {
return -1;
}
int left = (valid - position);
return (left <= 0) ? 0 : left;
}
@Override
public byte readByte() throws IOException {
if (!readyBuffer()) {
throw new EOFException();
}
return uncompressed[position++];
}
public int read(byte[] buffer, int offset, int length, boolean fullRead) throws IOException {
if (length < 1) {
return 0;
}
if (!readyBuffer()) {
return -1;
}
// First let's read however much data we happen to have...
int chunkLength = Math.min(valid - position, length);
System.arraycopy(uncompressed, position, buffer, offset, chunkLength);
position += chunkLength;
if (chunkLength == length || !fullRead) {
return chunkLength;
}
// Need more data, then
int totalRead = chunkLength;
do {
offset += chunkLength;
if (!readyBuffer()) {
break;
}
chunkLength = Math.min(valid - position, (length - totalRead));
System.arraycopy(uncompressed, position, buffer, offset, chunkLength);
position += chunkLength;
totalRead += chunkLength;
} while (totalRead < length);
return totalRead;
}
@Override
public void readBytes(byte[] b, int offset, int len) throws IOException {
int result = read(b, offset, len, true /* we want to have full reads, thats the contract... */);
if (result < len) {
throw new EOFException();
}
}
@Override
public long getFilePointer() {
return currentUncompressedChunkPointer + position;
}
@Override
public void seek(long pos) throws IOException {
int idx = (int) (pos / uncompressedLength);
if (idx >= offsets.size()) {
// set the next "readyBuffer" to EOF
currentOffsetIdx = idx;
position = 0;
valid = 0;
return;
}
// TODO: optimize so we won't have to readyBuffer on seek, can keep the position around, and set it on readyBuffer in this case
if (idx != currentOffsetIdx) {
long pointer = offsets.get(idx);
in.seek(pointer);
position = 0;
valid = 0;
currentOffsetIdx = idx - 1; // we are going to increase it in readyBuffer...
readyBuffer();
}
position = (int) (pos % uncompressedLength);
}
@Override
public long length() {
return totalUncompressedLength;
}
@Override
public void close() throws IOException {
position = valid = 0;
if (!closed) {
closed = true;
doClose();
in.close();
}
}
protected abstract void doClose() throws IOException;
protected boolean readyBuffer() throws IOException {
if (position < valid) {
return true;
}
if (closed) {
return false;
}
// we reached the end...
if (currentOffsetIdx + 1 >= offsets.size()) {
return false;
}
valid = uncompress(in, uncompressed);
if (valid < 0) {
return false;
}
currentOffsetIdx++;
currentUncompressedChunkPointer = ((long) currentOffsetIdx) * uncompressedLength;
position = 0;
return (position < valid);
}
protected abstract void readHeader(IndexInput in) throws IOException;
/**
* Uncompress the data into the out array, returning the size uncompressed
*/
protected abstract int uncompress(IndexInput in, byte[] out) throws IOException;
@Override
public IndexInput clone() {
// we clone and we need to make sure we keep the same positions!
CompressedIndexInput cloned = (CompressedIndexInput) super.clone();
cloned.uncompressed = new byte[uncompressedLength];
System.arraycopy(uncompressed, 0, cloned.uncompressed, 0, uncompressedLength);
cloned.in = (IndexInput) cloned.in.clone();
return cloned;
}
}
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