io.polaris.core.compress.Deflate Maven / Gradle / Ivy
package io.polaris.core.compress;
import io.polaris.core.io.IO;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterOutputStream;
/**
* Deflate算法
* Deflate是同时使用了LZ77算法与哈夫曼编码（Huffman Coding）的一个无损数据压缩算法。
*
* @author Qt
* @since 1.8
*/
public class Deflate implements Closeable {
private final InputStream source;
private OutputStream target;
private final boolean nowrap;
/**
* 创建Deflate
*
* @param source 源流
* @param target 目标流
* @param nowrap {@code true}表示兼容Gzip压缩
* @return this
*/
public static Deflate of(InputStream source, OutputStream target, boolean nowrap) {
return new Deflate(source, target, nowrap);
}
/**
* 构造
*
* @param source 源流
* @param target 目标流
* @param nowrap {@code true}表示兼容Gzip压缩
*/
public Deflate(InputStream source, OutputStream target, boolean nowrap) {
this.source = source;
this.target = target;
this.nowrap = nowrap;
}
/**
* 获取目标流
*
* @return 目标流
*/
public OutputStream getTarget() {
return this.target;
}
/**
* 将普通数据流压缩
*
* @param level 压缩级别，0~9
* @return this
*/
public Deflate deflate(int level) throws IOException {
target = (target instanceof DeflaterOutputStream) ?
(DeflaterOutputStream) target : new DeflaterOutputStream(target, new Deflater(level, nowrap));
IO.copy(source, target);
((DeflaterOutputStream) target).finish();
return this;
}
/**
* 将压缩流解压到target中
*
* @return this
*/
public Deflate inflate() throws IOException {
target = (target instanceof InflaterOutputStream) ?
(InflaterOutputStream) target : new InflaterOutputStream(target, new Inflater(nowrap));
IO.copy(source, target);
((InflaterOutputStream) target).finish();
return this;
}
@Override
public void close() {
IO.close(this.target);
IO.close(this.source);
}
}