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snappy-java
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Write a version header and block size information to the output of SnappyOutputStream

This commit is contained in:
Taro L. Saito 2011-03-31 20:14:40 +09:00
parent a63251ac04
commit b1158e563f
2 changed files with 26 additions and 7 deletions
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31
src/main/java/org/xerial/snappy/SnappyOutputStream.java
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@ -26,6 +26,7 @@ package org.xerial.snappy;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
/**
* This class implements a stream filter for writing compressed data using
@ -42,18 +43,36 @@ import java.io.OutputStream;
*/
public class SnappyOutputStream extends OutputStream
{
protected final OutputStream out;
public static final int HEADER_SIZE = 16 + 4; // version (16 bytes) & block size (int: 4 bytes)
private int cursor = 0;
private 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;
protected byte[] uncompressed;
protected byte[] compressed;
protected final int BLOCK_SIZE = 1 << 15; // use 2^15 = 32KB as block size
public SnappyOutputStream(OutputStream out) throws IOException {
this(out, DEFAULT_BLOCK_SIZE);
}
public SnappyOutputStream(OutputStream out) {
public SnappyOutputStream(OutputStream out, int blockSize) throws IOException {
this.out = out;
uncompressed = new byte[BLOCK_SIZE];
compressed = new byte[Snappy.maxCompressedLength(BLOCK_SIZE) + 4];
this.blockSize = blockSize;
uncompressed = new byte[blockSize];
compressed = new byte[Snappy.maxCompressedLength(blockSize)];
writeHeader();
}
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");
assert (version.length <= 16);
System.arraycopy(version, 0, header, 0, version.length);
out.write(header);
writeInt(out, blockSize);
}
@Override

2
src/test/java/org/xerial/snappy/SnappyOutputStreamTest.java
View File

@ -61,7 +61,7 @@ public class SnappyOutputStreamTest
ByteArrayOutputStream decompressed = new ByteArrayOutputStream();
byte[] compressed = buf.toByteArray();
// decompress
for (int cursor = 0; cursor < compressed.length;) {
for (int cursor = SnappyOutputStream.HEADER_SIZE; cursor < compressed.length;) {
int chunkSize = SnappyOutputStream.readInt(compressed, cursor);
cursor += 4;
byte[] tmpOut = new byte[Snappy.uncompressedLength(compressed, cursor, chunkSize)];