package com.gh.common.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GzipUtils {

    private final static int BUFFER = 1024;

    public static byte[] compressBytes(byte[] compressed) {
        ByteArrayInputStream bais = null;
        ByteArrayOutputStream baos = null;
        try {
            bais = new ByteArrayInputStream(compressed);
            baos = new ByteArrayOutputStream();
            compress(bais, baos);
            return baos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
            return compressed;
        } finally {
            if (bais != null) {
                try {
                    bais.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (baos != null) {
                try {
                    baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /*
     * 数据压缩
     */
    public static void compress(InputStream is, OutputStream os) throws IOException {
        GZIPOutputStream gos = null;
        try {
            gos = new GZIPOutputStream(os);
            int count;
            byte data[] = new byte[BUFFER];
            while ((count = is.read(data, 0, BUFFER)) != -1) {
                gos.write(data, 0, count);
            }
            gos.flush();
            gos.finish();
            gos.close();
        } finally {
            if (gos != null) {
                gos.close();
            }
        }
    }

    public static byte[] decompressBytes(byte[] compressed) {
        ByteArrayInputStream bais = null;
        ByteArrayOutputStream baos = null;
        try {
            bais = new ByteArrayInputStream(compressed);
            baos = new ByteArrayOutputStream();
            decompress(bais, baos);
            return baos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
            return compressed;
        } finally {
            if (bais != null) {
                try {
                    bais.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (baos != null) {
                try {
                    baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    /*
     * 数据解压缩
     */
    public static void decompress(InputStream is, OutputStream os) throws IOException {
        GZIPInputStream gis = null;
        try {
            gis = new GZIPInputStream(is);
            int count;
            byte data[] = new byte[BUFFER];
            while ((count = gis.read(data, 0, BUFFER)) != -1) {
                os.write(data, 0, count);
            }
        } finally {
            if (gis != null) {
                gis.close();
            }
        }
    }

}