SSB_HighSpeed_Modem/hsmodem/fec/schifra_crc.hpp

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2020-11-05 13:11:57 -05:00
/*
(**************************************************************************)
(* *)
(* 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_CRC_HPP
#define INCLUDE_SCHIFRA_CRC_HPP
#include <iostream>
#include <string>
namespace schifra
{
class crc32
{
public:
typedef std::size_t crc32_t;
crc32(const crc32_t& _key, const crc32_t& _state = 0x00)
: key(_key),
state(_state),
initial_state(_state)
{
initialize_crc32_table();
}
void reset()
{
state = initial_state;
}
void update_1byte(const unsigned char data)
{
state = (state >> 8) ^ table[data];
}
void update(const unsigned char data[], const std::size_t& count)
{
for (std::size_t i = 0; i < count; ++i)
{
update_1byte(data[i]);
}
}
void update(char data[], const std::size_t& count)
{
for (std::size_t i = 0; i < count; ++i)
{
update_1byte(static_cast<unsigned char>(data[i]));
}
}
void update(const std::string& data)
{
for (std::size_t i = 0; i < data.size(); ++i)
{
update_1byte(static_cast<unsigned char>(data[i]));
}
}
void update(const std::size_t& data)
{
update_1byte(static_cast<unsigned char>((data ) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 8) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 16) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 24) & 0xFF));
}
crc32_t crc()
{
return state;
}
private:
crc32& operator=(const crc32&);
void initialize_crc32_table()
{
for (std::size_t i = 0; i < 0xFF; ++i)
{
crc32_t reg = i;
for (int j = 0; j < 0x08; ++j)
{
reg = ((reg & 1) ? (reg >> 1) ^ key : reg >> 1);
}
table[i] = reg;
}
}
protected:
crc32_t key;
crc32_t state;
const crc32_t initial_state;
crc32_t table[256];
};
class schifra_crc : public crc32
{
public:
schifra_crc(const crc32_t _key)
: crc32(_key,0xAAAAAAAA)
{}
void update(const unsigned char& data)
{
state = ((state >> 8) ^ table[data]) ^ ((state << 8) ^ table[~data]);
}
void update(const unsigned char data[], const std::size_t& count)
{
for (std::size_t i = 0; i < count; ++i)
{
update_1byte(data[i]);
}
}
void update(const char data[], const std::size_t& count)
{
for (std::size_t i = 0; i < count; ++i)
{
update_1byte(static_cast<unsigned char>(data[i]));
}
}
void update(const std::string& data)
{
for (std::size_t i = 0; i < data.size(); ++i)
{
update_1byte(static_cast<unsigned char>(data[i]));
}
}
void update(const std::size_t& data)
{
update_1byte(static_cast<unsigned char>((data ) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 8) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 16) & 0xFF));
update_1byte(static_cast<unsigned char>((data >> 24) & 0xFF));
}
};
} // namespace schifra
#endif