hadoop RSLegacyRawEncoder 源码
haddop RSLegacyRawEncoder 代码
文件路径:/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/rawcoder/RSLegacyRawEncoder.java
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.io.erasurecode.rawcoder;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.io.erasurecode.ErasureCoderOptions;
import org.apache.hadoop.io.erasurecode.rawcoder.util.RSUtil;
import java.nio.ByteBuffer;
import java.util.Arrays;
/**
* A raw erasure encoder in RS code scheme in pure Java in case native one
* isn't available in some environment. Please always use native implementations
* when possible.
*/
@InterfaceAudience.Private
public class RSLegacyRawEncoder extends RawErasureEncoder {
private int[] generatingPolynomial;
public RSLegacyRawEncoder(ErasureCoderOptions coderOptions) {
super(coderOptions);
assert (getNumDataUnits() + getNumParityUnits() < RSUtil.GF.getFieldSize());
int[] primitivePower = RSUtil.getPrimitivePower(getNumDataUnits(),
getNumParityUnits());
// compute generating polynomial
int[] gen = {1};
int[] poly = new int[2];
for (int i = 0; i < getNumParityUnits(); i++) {
poly[0] = primitivePower[i];
poly[1] = 1;
gen = RSUtil.GF.multiply(gen, poly);
}
// generating polynomial has all generating roots
generatingPolynomial = gen;
}
@Override
protected void doEncode(ByteBufferEncodingState encodingState) {
CoderUtil.resetOutputBuffers(encodingState.outputs,
encodingState.encodeLength);
// parity units + data units
ByteBuffer[] all = new ByteBuffer[encodingState.outputs.length +
encodingState.inputs.length];
if (allowChangeInputs()) {
System.arraycopy(encodingState.outputs, 0, all, 0,
encodingState.outputs.length);
System.arraycopy(encodingState.inputs, 0, all,
encodingState.outputs.length, encodingState.inputs.length);
} else {
System.arraycopy(encodingState.outputs, 0, all, 0,
encodingState.outputs.length);
/**
* Note when this coder would be really (rarely) used in a production
* system, this can be optimized to cache and reuse the new allocated
* buffers avoiding reallocating.
*/
ByteBuffer tmp;
for (int i = 0; i < encodingState.inputs.length; i++) {
tmp = ByteBuffer.allocate(encodingState.inputs[i].remaining());
tmp.put(encodingState.inputs[i]);
tmp.flip();
all[encodingState.outputs.length + i] = tmp;
}
}
// Compute the remainder
RSUtil.GF.remainder(all, generatingPolynomial);
}
@Override
protected void doEncode(ByteArrayEncodingState encodingState) {
int dataLen = encodingState.encodeLength;
CoderUtil.resetOutputBuffers(encodingState.outputs,
encodingState.outputOffsets, dataLen);
// parity units + data units
byte[][] all = new byte[encodingState.outputs.length +
encodingState.inputs.length][];
int[] allOffsets = new int[encodingState.outputOffsets.length +
encodingState.inputOffsets.length];
if (allowChangeInputs()) {
System.arraycopy(encodingState.outputs, 0, all, 0,
encodingState.outputs.length);
System.arraycopy(encodingState.inputs, 0, all,
encodingState.outputs.length, encodingState.inputs.length);
System.arraycopy(encodingState.outputOffsets, 0, allOffsets, 0,
encodingState.outputOffsets.length);
System.arraycopy(encodingState.inputOffsets, 0, allOffsets,
encodingState.outputOffsets.length,
encodingState.inputOffsets.length);
} else {
System.arraycopy(encodingState.outputs, 0, all, 0,
encodingState.outputs.length);
System.arraycopy(encodingState.outputOffsets, 0, allOffsets, 0,
encodingState.outputOffsets.length);
for (int i = 0; i < encodingState.inputs.length; i++) {
all[encodingState.outputs.length + i] =
Arrays.copyOfRange(encodingState.inputs[i],
encodingState.inputOffsets[i],
encodingState.inputOffsets[i] + dataLen);
}
}
// Compute the remainder
RSUtil.GF.remainder(all, allOffsets, dataLen, generatingPolynomial);
}
}
相关信息
相关文章
hadoop AbstractNativeRawDecoder 源码
hadoop AbstractNativeRawEncoder 源码
hadoop ByteArrayDecodingState 源码
hadoop ByteArrayEncodingState 源码
hadoop ByteBufferDecodingState 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦