Example usage for org.apache.hadoop.io.erasurecode.rawcoder RawErasureDecoder decode

Introduction

In this page you can find the example usage for org.apache.hadoop.io.erasurecode.rawcoder RawErasureDecoder decode.

Prototype

public void decode(ECChunk[] inputs, int[] erasedIndexes, ECChunk[] outputs) throws IOException 

Source Link

Document

Decode with inputs and erasedIndexes, generates outputs.

Usage

From source file:com.mellanox.erasurecode.rawcoder.RawErasureCoderValidationTest.java

License:Apache License

public static void performDecode(RawErasureDecoder decoder, RandomAccessFile inputFileReader, String inputFile,
        RandomAccessFile encodedFileReader, int[] erasuresArray, int[] redundantArray) throws IOException {

    boolean isDirect = (Boolean) decoder.getCoderOption(CoderOption.PREFER_DIRECT_BUFFER);

    ByteBuffer[] inputFileInputs = allocateBuffers(isDirect, numData);
    ByteBuffer[] encodedFileInputs = allocateBuffers(isDirect, numCode);
    ByteBuffer[] decodeInputs = allocateBuffers(isDirect, numData + numCode);
    ByteBuffer[] decodeOutputs = allocateBuffers(isDirect, erasuresArray.length);

    FileChannel inputFileChannel = inputFileReader.getChannel();
    FileChannel encodedFileChannel = encodedFileReader.getChannel();

    FileOutputStream inputfileOutputStream = new FileOutputStream(
            new File(inputFile + "." + coderIndex + ".decode.data"));
    FileChannel inputfileOutChannel = inputfileOutputStream.getChannel();

    FileOutputStream encodedFileOutputStream = new FileOutputStream(
            new File(inputFile + "." + coderIndex + ".decode.code"));
    FileChannel encodedFileOutChannel = encodedFileOutputStream.getChannel();

    long bytesLeft;

    ByteBuffer buffer;//from   www.j  ava 2 s .  c o  m

    // // read input files
    while ((bytesLeft = inputFileChannel.read(inputFileInputs)) > 0
            && encodedFileChannel.read(encodedFileInputs) > 0) {

        // memset unfull buffers and reset all input and encoded buffers
        resetBuffers(inputFileInputs, chunkSizeB);
        resetBuffers(encodedFileInputs, chunkSizeB);

        // prepare the decode inputs
        for (int i = 0; i < numData + numCode; i++) {
            decodeInputs[i] = i < numData ? inputFileInputs[i].duplicate()
                    : encodedFileInputs[i - numData].duplicate();
        }

        // unset erased indexes
        for (int erasedIndex : erasuresArray) {
            decodeInputs[erasedIndex] = null;
        }

        // unset redundant indexes
        for (int redundant : redundantArray) {
            decodeInputs[redundant] = null;
        }

        // perform decode
        decoder.decode(decodeInputs, erasuresArray, decodeOutputs);

        // reset positions
        resetBuffers(decodeInputs);
        resetBuffers(decodeOutputs);

        // set redundant indexes
        for (int redundant : redundantArray) {
            decodeInputs[redundant] = redundant < numData ? inputFileInputs[redundant].duplicate()
                    : encodedFileInputs[redundant - numData].duplicate();
        }

        // write to data file
        for (int i = 0; i < numData; i++) {
            buffer = decodeInputs[i] != null ? decodeInputs[i]
                    : decodeOutputs[getPlaceInArray(erasuresArray, i)];
            buffer.limit(Math.min(buffer.limit(), (int) bytesLeft));
            bytesLeft -= bytesLeft > 0 ? inputfileOutChannel.write(buffer) : 0;
        }

        // write to code file
        for (int i = numData; i < numData + numCode; i++) {
            buffer = decodeInputs[i] != null ? decodeInputs[i]
                    : decodeOutputs[getPlaceInArray(erasuresArray, i)];
            encodedFileOutChannel.write(buffer);
        }

        // reset decodeOutputs positions
        resetBuffers(decodeOutputs);
    }

    decoder.release();
    inputFileChannel.close();
    encodedFileChannel.close();
    inputfileOutputStream.close();
    encodedFileOutputStream.close();
}

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