ESP32-CAM-Video-Recorder/vA1/CRC32.h

78 wiersze
2.2 KiB
C++

// mods by James Zahary Dec 28, 2021 https://github.com/jameszah/ESPxWebFlMgr
// based on https://github.com/holgerlembke/ESPxWebFlMgr
//
// Copyright (c) 2013 Christopher Baker <https://christopherbaker.net>
//
// SPDX-License-Identifier: MIT
//
#pragma once
#include "Arduino.h"
/// \brief A class for calculating the CRC32 checksum from arbitrary data.
/// \sa http://forum.arduino.cc/index.php?topic=91179.0
class CRC32
{
public:
/// \brief Initialize an empty CRC32 checksum.
CRC32();
/// \brief Reset the checksum claculation.
void reset();
/// \brief Update the current checksum caclulation with the given data.
/// \param data The data to add to the checksum.
void update(const uint8_t& data);
/// \brief Update the current checksum caclulation with the given data.
/// \tparam Type The data type to read.
/// \param data The data to add to the checksum.
template <typename Type>
void update(const Type& data)
{
update(&data, 1);
}
/// \brief Update the current checksum caclulation with the given data.
/// \tparam Type The data type to read.
/// \param data The array to add to the checksum.
/// \param size Size of the array to add.
template <typename Type>
void update(const Type* data, size_t size)
{
size_t nBytes = size * sizeof(Type);
const uint8_t* pData = (const uint8_t*)data;
for (size_t i = 0; i < nBytes; i++)
{
update(pData[i]);
}
}
/// \returns the caclulated checksum.
uint32_t finalize() const;
/// \brief Calculate the checksum of an arbitrary data array.
/// \tparam Type The data type to read.
/// \param data A pointer to the data to add to the checksum.
/// \param size The size of the data to add to the checksum.
/// \returns the calculated checksum.
template <typename Type>
static uint32_t calculate(const Type* data, size_t size)
{
CRC32 crc;
crc.update(data, size);
return crc.finalize();
}
private:
/// \brief The internal checksum state.
uint32_t _state = ~0L;
};