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schifra_reed_solomon_file_decoder.hpp
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schifra_reed_solomon_file_decoder.hpp
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/*
(**************************************************************************)
(* *)
(* Schifra *)
(* Reed-Solomon Error Correcting Code Library *)
(* *)
(* Release Version 0.0.1 *)
(* http://www.schifra.com *)
(* Copyright (c) 2000-2020 Arash Partow, All Rights Reserved. *)
(* *)
(* The Schifra Reed-Solomon error correcting code library and all its *)
(* components are supplied under the terms of the General Schifra License *)
(* agreement. The contents of the Schifra Reed-Solomon error correcting *)
(* code library and all its components may not be copied or disclosed *)
(* except in accordance with the terms of that agreement. *)
(* *)
(* URL: http://www.schifra.com/license.html *)
(* *)
(**************************************************************************)
*/
#ifndef INCLUDE_SCHIFRA_REED_SOLOMON_FILE_DECODER_HPP
#define INCLUDE_SCHIFRA_REED_SOLOMON_FILE_DECODER_HPP
#include <iostream>
#include <fstream>
#include "schifra_reed_solomon_block.hpp"
#include "schifra_reed_solomon_decoder.hpp"
#include "schifra_fileio.hpp"
namespace schifra
{
namespace reed_solomon
{
template <std::size_t code_length, std::size_t fec_length, std::size_t data_length = code_length - fec_length>
class file_decoder
{
public:
typedef decoder<code_length,fec_length> decoder_type;
typedef typename decoder_type::block_type block_type;
file_decoder(const decoder_type& decoder,
const std::string& input_file_name,
const std::string& output_file_name)
: current_block_index_(0)
{
std::size_t remaining_bytes = schifra::fileio::file_size(input_file_name);
if (remaining_bytes == 0)
{
std::cout << "reed_solomon::file_decoder() - Error: input file has ZERO size." << std::endl;
return;
}
std::ifstream in_stream(input_file_name.c_str(),std::ios::binary);
if (!in_stream)
{
std::cout << "reed_solomon::file_decoder() - Error: input file could not be opened." << std::endl;
return;
}
std::ofstream out_stream(output_file_name.c_str(),std::ios::binary);
if (!out_stream)
{
std::cout << "reed_solomon::file_decoder() - Error: output file could not be created." << std::endl;
return;
}
current_block_index_ = 0;
while (remaining_bytes >= code_length)
{
process_complete_block(decoder,in_stream,out_stream);
remaining_bytes -= code_length;
current_block_index_++;
}
if (remaining_bytes > 0)
{
process_partial_block(decoder,in_stream,out_stream,remaining_bytes);
}
in_stream.close();
out_stream.close();
}
private:
inline void process_complete_block(const decoder_type& decoder,
std::ifstream& in_stream,
std::ofstream& out_stream)
{
in_stream.read(&buffer_[0],static_cast<std::streamsize>(code_length));
copy<char,code_length,fec_length>(buffer_,code_length,block_);
if (!decoder.decode(block_))
{
std::cout << "reed_solomon::file_decoder.process_complete_block() - Error during decoding of block " << current_block_index_ << "!" << std::endl;
return;
}
for (std::size_t i = 0; i < data_length; ++i)
{
buffer_[i] = static_cast<char>(block_[i]);
}
out_stream.write(&buffer_[0],static_cast<std::streamsize>(data_length));
}
inline void process_partial_block(const decoder_type& decoder,
std::ifstream& in_stream,
std::ofstream& out_stream,
const std::size_t& read_amount)
{
if (read_amount <= fec_length)
{
std::cout << "reed_solomon::file_decoder.process_partial_block() - Error during decoding of block " << current_block_index_ << "!" << std::endl;
return;
}
in_stream.read(&buffer_[0],static_cast<std::streamsize>(read_amount));
for (std::size_t i = 0; i < (read_amount - fec_length); ++i)
{
block_.data[i] = static_cast<typename block_type::symbol_type>(buffer_[i]);
}
if ((read_amount - fec_length) < data_length)
{
for (std::size_t i = (read_amount - fec_length); i < data_length; ++i)
{
block_.data[i] = 0;
}
}
for (std::size_t i = 0; i < fec_length; ++i)
{
block_.fec(i) = static_cast<typename block_type::symbol_type>(buffer_[(read_amount - fec_length) + i]);
}
if (!decoder.decode(block_))
{
std::cout << "reed_solomon::file_decoder.process_partial_block() - Error during decoding of block " << current_block_index_ << "!" << std::endl;
return;
}
for (std::size_t i = 0; i < (read_amount - fec_length); ++i)
{
buffer_[i] = static_cast<char>(block_.data[i]);
}
out_stream.write(&buffer_[0],static_cast<std::streamsize>(read_amount - fec_length));
}
block_type block_;
std::size_t current_block_index_;
char buffer_[code_length];
};
} // namespace reed_solomon
} // namespace schifra
#endif