tyler.durden/snappy-java
1
0
Fork 0
mirror of https://github.com/xerial/snappy-java.git synced 2025-07-22 05:24:27 +02:00
Code Issues Packages Projects Releases Wiki Activity

Add preamble to Snappy stream

Browse Source
This commit is contained in:
Taro L. Saito 2011-03-31 21:47:47 +09:00
parent b1158e563f
commit 0fcb9f8b9a
2 changed files with 81 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
src/main/java/org/xerial/snappy/SnappyInputStream.java Executable file
View File

@ -0,0 +1,75 @@
/*--------------------------------------------------------------------------
* Copyright 2011 Taro L. Saito
*
* Licensed 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.
*--------------------------------------------------------------------------*/
//--------------------------------------
// XerialJ
//
// SnappyInputStream.java
// Since: 2011/03/31 20:14:56
//
// $URL$
// $Author$
//--------------------------------------
package org.xerial.snappy;
import java.io.IOException;
import java.io.InputStream;
/**
* A stream filter for reading data compressed by {@link SnappyOutputStream}.
*
* @author leo
*
*/
public class SnappyInputStream extends InputStream
{
protected final InputStream in;
private int blockSize = SnappyOutputStream.DEFAULT_BLOCK_SIZE;
private byte[] compressed;
private byte[] uncompressed;
public SnappyInputStream(InputStream input) throws IOException {
this.in = input;
readHeader();
}
protected void readHeader() throws IOException {
byte[] header = new byte[SnappyOutputStream.PREAMBLE_SIZE];
int readBytes = in.read(header);
if (readBytes != header.length) {
throw new IOException("Invalid Snappy stream");
}
String headerStr = new String(header, 0, SnappyOutputStream.HEADER_SIZE, "UTF-8");
if (!headerStr.startsWith(SnappyOutputStream.STREAM_FORMAT_VERSION)) {
throw new IOException("Incompatible stream version");
}
blockSize = SnappyOutputStream.readInt(header, SnappyOutputStream.HEADER_SIZE);
if (blockSize < 0) {
throw new IOException("Invalid block size: " + blockSize);
}
compressed = new byte[blockSize];
uncompressed = new byte[blockSize];
}
@Override
public int read() throws IOException {
// TODO Auto-generated method stub
return 0;
}
}

10
src/main/java/org/xerial/snappy/SnappyOutputStream.java
View File

@ -43,13 +43,15 @@ import java.util.Arrays;
*/
public class SnappyOutputStream extends OutputStream
{
public static final int HEADER_SIZE = 16 + 4; // version (16 bytes) & block size (int: 4 bytes)
public final static String STREAM_FORMAT_VERSION = "snappy-1.0.1";
public static final int HEADER_SIZE = 16; // version (16 bytes)
public static final int PREAMBLE_SIZE = HEADER_SIZE + 4; // version (16 bytes) & block size (int: 4 bytes)
private static final int DEFAULT_BLOCK_SIZE = 1 << 15; // use 2^15 = 32KB as block size
static final int DEFAULT_BLOCK_SIZE = 1 << 15; // use 2^15 = 32KB as block size
protected final OutputStream out;
private final int blockSize;
private int cursor = 0;
private int cursor = 0;
protected byte[] uncompressed;
protected byte[] compressed;
@ -68,7 +70,7 @@ public class SnappyOutputStream extends OutputStream
protected void writeHeader() throws IOException {
byte[] header = new byte[16]; // header size
Arrays.fill(header, (byte) 0);
byte[] version = "snappy-1.0.1".getBytes("UTF-8");
byte[] version = STREAM_FORMAT_VERSION.getBytes("UTF-8");
assert (version.length <= 16);
System.arraycopy(version, 0, header, 0, version.length);
out.write(header);