mirror of
https://github.com/QuasarApp/QuasarAppLib.git
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84 lines
2.7 KiB
C
84 lines
2.7 KiB
C
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/*
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* Copyright (C) 2025-2025 QuasarApp.
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* Distributed under the lgplv3 software license, see the accompanying
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* Everyone is permitted to copy and distribute verbatim copies
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* of this license document, but changing it is not allowed.
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*/
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#ifndef CRC32CONSTEXPER_H
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#define CRC32CONSTEXPER_H
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#include <array>
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#include <cstddef>
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#include <cstdint>
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namespace QuasarAppUtils {
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/**
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* @brief generateCrc32Table This method generate crc32 table for fast calculate crc32 hash.
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* @param polynomial This is polynomial for crc32 hash.
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* @return return table for fast calculate crc32 hash.
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* @note This method is constexpr and available in compile time.
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*/
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constexpr std::array<uint32_t, 256> generateCrc32Table(uint32_t polynomial = 0xEDB88320) {
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std::array<uint32_t, 256> table{};
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for (uint32_t i = 0; i < 256; ++i) {
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uint32_t crc = i;
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for (int j = 0; j < 8; ++j) {
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crc = (crc >> 1) ^ (-(crc & 1) & polynomial);
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}
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table[i] = crc;
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}
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return table;
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}
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/**
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* @brief crc32Table This is crc32 table for fast calculate crc32 hash.
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* @note This table is used for fast calculate crc32 hash.
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*/
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constexpr std::array<uint32_t, 256> crc32Table = generateCrc32Table();
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/**
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* @brief calculateCrc32 This method calculate crc32 hash for data.
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* @param data This is data for calculate crc32 hash.
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* @param size This is size of data.
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* @param initialCrc This is initial crc value.
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* @return return crc32 hash for data.
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* @note This method is constexpr and available in compile time.
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*/
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constexpr uint32_t calculateCrc32(const char* data, size_t size, uint32_t initialCrc = 0xFFFFFFFF) {
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uint32_t crc = initialCrc;
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for (size_t i = 0; i < size; ++i) {
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crc = crc32Table[(crc ^ data[i]) & 0xFF] ^ (crc >> 8);
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}
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return crc ^ 0xFFFFFFFF;
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}
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/**
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* @brief calculateCrc16 This method calculate crc16 hash for data.
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* @param data This is data for calculate crc16 hash.
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* @param size This is size of data.
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* @param initialCrc This is initial crc value.
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* @return return crc16 hash for data.
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* @note This method is constexpr and available in compile time.
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*/
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constexpr uint16_t calculateCrc16(const char* data, size_t size, uint32_t initialCrc = 0xFFFFFFFF) {
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return calculateCrc32(data, size, initialCrc) % 0xFFFF;
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}
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/**
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* @brief calculateCrc8 This method calculate crc8 hash for data.
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* @param data This is data for calculate crc8 hash.
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* @param size This is size of data.
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* @param initialCrc This is initial crc value.
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* @return return crc8 hash for data.
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* @note This method is constexpr and available in compile time.
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*/
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constexpr uint16_t calculateCrc8(const char* data, size_t size, uint32_t initialCrc = 0xFFFFFFFF) {
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return calculateCrc32(data, size, initialCrc) % 0xFF;
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}
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}
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#endif // CRC32CONSTEXPER_H
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