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encoder.cpp
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encoder.cpp
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/*
Copyright 2013 sweetbomber (ffrogger0@yahoo.com)
This file is part of the Library of Online-Codes (LOnC).
The Library of Online-Codes is free software:
you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
The Library of Online-Codes is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with the Library of Online-Codes.
If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <boost/random/uniform_real.hpp>
#include <math.h>
#include "codec.h"
OcdEncoder::OcdEncoder(const uint8_t *inputBuffer,
uint32_t inputBufferSize,
uint32_t blockSize,
uint32_t q,
double epsilon) {
mRhoList.clear();
mBlockSize = blockSize;
mQ = q;
SetEpsilon(epsilon);
/* Calculate total memory, including auxiliary blocks */
mNumberOfSourceBlocks = ((inputBufferSize + mBlockSize - 1)/mBlockSize);
mNumberOfAuxiliaryBlocks = mNumberOfSourceBlocks*(mQ*mEpsilon*0.55);
mNumberOfIntermediateBlocks = mNumberOfSourceBlocks + mNumberOfAuxiliaryBlocks;
/* Redirect source data */
mSourceBuffer.buffer = (uint8_t *)inputBuffer;
mSourceBuffer.bufferSize = inputBufferSize;
/* Allocate required memory */
mIntermediateBuffer.bufferSize = mNumberOfIntermediateBlocks*mBlockSize;
mIntermediateBuffer.buffer = (uint8_t *) malloc(sizeof(uint8_t)*mIntermediateBuffer.bufferSize);
/* Copy source data to intermediate data, and fill remaining space */
memcpy(mIntermediateBuffer.buffer, inputBuffer, inputBufferSize);
memset((mIntermediateBuffer.buffer) + inputBufferSize, 0, mIntermediateBuffer.bufferSize - inputBufferSize);
PreEncode();
}
OcdEncoder::~OcdEncoder() {
free(mIntermediateBuffer.buffer);
mRhoList.clear();
}
void OcdEncoder::PreEncode() {
uint32_t blockIdx, qCounter;
uint8_t *srcBlock, *dstBlock;
SeedCodec(1); /* Ill probably let the seed to be a free parameter */
for(blockIdx = 0; blockIdx < mNumberOfSourceBlocks; blockIdx++) {
GetBlock(mIntermediateBuffer.buffer, blockIdx, &srcBlock);
for(qCounter = 0; qCounter < mQ; qCounter++) {
GetBlock(mIntermediateBuffer.buffer, mNumberOfSourceBlocks + Random(mNumberOfAuxiliaryBlocks), &dstBlock);
BlockXor(dstBlock, srcBlock);
}
}
}
void OcdEncoder::Encode(uint8_t *checkBlock, blockID_t blockID) {
uint32_t degree, i;
uint8_t *srcBlock;
SeedCodec(blockID);
degree = GetDegree();
/* Clear checkBlock */
memset(checkBlock, 0, mBlockSize);
/* Pick 'degree' random blocks, and xor them. */
for(i = 0; i < degree; i++) {
/* Get a block */
GetBlock(mIntermediateBuffer.buffer, Random(mNumberOfIntermediateBlocks), &srcBlock);
/* Xor srcBlock with checkblock, and store the result in the later */
BlockXor(checkBlock, srcBlock);
}
printf("ID: %08X deg: %d\n", blockID, degree);
}