使用輸入/輸出流的 Java LZ4 壓縮

Question

我正在使用 jpountz LZ4 來嘗試壓縮文件，我想使用 Java 文件輸入和輸出流讀取和輸出文件。 我試圖在網上找到一個解決方案，但什么也沒有，我發現了一個關於如何正確實現 LZ4 的上一個 stackoverflow 問題，我已經接受並嘗試修改它以使用流，但我不確定這是否是正確或者它是否有效。

在文本文件上運行壓縮時，它會輸出一個缺少某些字符或用符號替換的文件

ðHello world Heðo world Hello ðrld Hello worlðHello worl

但是當使用圖像文件運行它時，它會引發越界錯誤。 我也無法使解壓縮工作，因為它會引發輸入緩沖區的錯誤解碼偏移 3。

這是我的代碼，任何幫助將不勝感激，謝謝

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

所以我通過使用 LZ4block 輸入/輸出流解決了我的問題

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

只看代碼，我會說你在這里出錯了：

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

您已經在壓縮中修剪了 outputBuffer。 嘗試：

out.write(outputBuffer);