使用输入/输出流的 Java LZ4 压缩

Question

我正在使用 jpountz LZ4 来尝试压缩文件，我想使用 Java 文件输入和输出流读取和输出文件。 我试图在网上找到一个解决方案，但什么也没有，我发现了一个关于如何正确实现 LZ4 的上一个 stackoverflow 问题，我已经接受并尝试修改它以使用流，但我不确定这是否是正确或者它是否有效。

在文本文件上运行压缩时，它会输出一个缺少某些字符或用符号替换的文件

ðHello world Heðo world Hello ðrld Hello worlðHello worl

但是当使用图像文件运行它时，它会引发越界错误。 我也无法使解压缩工作，因为它会引发输入缓冲区的错误解码偏移 3。

这是我的代码，任何帮助将不胜感激，谢谢

public void LZ4Compress(InputStream in, OutputStream out){
    int noBytesRead = 0;        //number of bytes read from input
    int noBytesProcessed = 0;   //number of bytes processed
    try {
        while ((noBytesRead = in.read(inputBuffer)) >= 0) {
            noBytesProcessed = inputBuffer.length;
            decompressedLength = inputBuffer.length;
            outputBuffer = compress(inputBuffer, decompressedLength);
            out.write(outputBuffer, 0, noBytesRead);
        }
        out.flush();
        in.close();
        out.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public void LZ4decompress(InputStream in, OutputStream out){
    int noBytesRead = 0;        //number of bytes read from input
    try {
        while((noBytesRead = in.read(inputBuffer)) >= 0){
            noBytesProcessed = inputBuffer.length;
            outputBuffer = decompress(inputBuffer);
            out.write(outputBuffer, 0, noBytesRead);

        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public static byte[] compress(byte[] src, int srcLen) {
    decompressedLength = srcLen;
    int maxCompressedLength = compressor.maxCompressedLength(decompressedLength);
    byte[] compressed = new byte[maxCompressedLength];
    int compressLen = compressor.compress(src, 0, decompressedLength, compressed, 0, maxCompressedLength);
    byte[] finalCompressedArray = Arrays.copyOf(compressed, compressLen);
    return finalCompressedArray;
}

private static LZ4SafeDecompressor decompressor = factory.safeDecompressor();

public static byte[] decompress(byte[] finalCompressedArray) {
    byte[] restored = new byte[finalCompressedArray.length];
    restored = decompressor.decompress(finalCompressedArray, finalCompressedArray.length);
    return restored;
}

Answer 1

所以我通过使用 LZ4block 输入/输出流解决了我的问题

public static void LZ4compress(String filename, String lz4file){
    byte[] buf = new byte[2048];
    try {
        String outFilename = lz4file;
        LZ4BlockOutputStream out = new LZ4BlockOutputStream(new FileOutputStream(outFilename), 32*1024*1024);
        FileInputStream in = new FileInputStream(filename);
        int len;
        while((len = in.read(buf)) > 0){
            out.write(buf, 0, len);
        }
        in.close();
        out.close();
    } catch (IOException e) {

    }
}

public static void LZ4Uncompress(String lz4file, String filename){
    byte[] buf = new byte[2048];
    try {
        String outFilename = filename;
        LZ4BlockInputStream in = new LZ4BlockInputStream(new FileInputStream(lz4file));
        FileOutputStream out = new FileOutputStream(outFilename);
        int len;
        while((len = in.read(buf)) > 0){
            out.write(buf, 0, len);
        }
        in.close();
        out.close();
    } catch (IOException e) {

    }
}

Answer 2

只看代码，我会说你在这里出错了：

 outputBuffer = compress(inputBuffer, decompressedLength);
 out.write(outputBuffer, 0, noBytesRead);

您已经在压缩中修剪了 outputBuffer。 尝试：

out.write(outputBuffer);