.. _program_listing_file_libspookyaction_include_pn532_checksum.hpp:

Program Listing for File checksum.hpp
=====================================

|exhale_lsh| :ref:`Return to documentation for file <file_libspookyaction_include_pn532_checksum.hpp>` (``libspookyaction/include/pn532/checksum.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   //
   // Created by Pietro Saccardi on 22/12/2020.
   //
   
   #ifndef PN532_BITS_ALGO_HPP
   #define PN532_BITS_ALGO_HPP
   
   #include <array>
   #include <cstdint>
   #include <numeric>
   #include <pn532/bits.hpp>
   
   namespace pn532 {
   
       [[nodiscard]] inline std::uint8_t compute_checksum(std::uint8_t byte);
   
       template <class ByteIterator>
       [[nodiscard]] std::uint8_t compute_checksum(ByteIterator begin, ByteIterator end);
   
       template <class ByteIterator>
       [[nodiscard]] std::uint8_t compute_checksum(std::uint8_t sum_init, ByteIterator begin, ByteIterator end);
   
       template <class ByteIterator>
       [[nodiscard]] bool checksum(ByteIterator begin, ByteIterator end);
   
   #ifndef DOXYGEN_SHOULD_SKIP_THIS
       namespace bits {
   
           [[nodiscard]] inline std::array<std::uint8_t, 2> length_and_checksum_short(std::uint8_t length);
   
           [[nodiscard]] inline std::array<std::uint8_t, 3> length_and_checksum_long(std::uint16_t length);
   
           [[nodiscard]] inline std::pair<std::uint8_t, bool> check_length_checksum(std::array<std::uint8_t, 2> const &data);
   
           [[nodiscard]] inline std::pair<std::uint16_t, bool> check_length_checksum(std::array<std::uint8_t, 3> const &data);
   
           [[nodiscard]] inline std::uint8_t host_to_pn532_command(command_code cmd);
   
           [[nodiscard]] inline command_code pn532_to_host_command(std::uint8_t cmd);
       }// namespace bits
   #endif
   }// namespace pn532
   
   namespace pn532 {
   
       std::uint8_t compute_checksum(std::uint8_t byte) {
           return ~byte + 1;
       }
   
       template <class ByteIterator>
       std::uint8_t compute_checksum(ByteIterator begin, ByteIterator end) {
           return compute_checksum(0, begin, end);
       }
   
       template <class ByteIterator>
       std::uint8_t compute_checksum(std::uint8_t sum_init, ByteIterator begin, ByteIterator end) {
           return compute_checksum(std::accumulate(begin, end, sum_init));
       }
   
       template <class ByteIterator>
       bool checksum(ByteIterator begin, ByteIterator end) {
           return (std::accumulate(begin, end, 0) & 0xff) == 0;
       }
   
       namespace bits {
           std::array<std::uint8_t, 2> length_and_checksum_short(std::uint8_t length) {
               return {length, compute_checksum(length)};
           }
   
           std::array<std::uint8_t, 3> length_and_checksum_long(std::uint16_t length) {
               const std::array<std::uint8_t, 2> bits = {std::uint8_t(length >> 8), std::uint8_t(length & 0xff)};
               return {bits[0], bits[1], compute_checksum(std::begin(bits), std::end(bits))};
           }
   
           std::pair<std::uint8_t, bool> check_length_checksum(std::array<std::uint8_t, 2> const &data) {
               return {data[0], checksum(std::begin(data), std::end(data))};
           }
   
           std::pair<std::uint16_t, bool> check_length_checksum(std::array<std::uint8_t, 3> const &data) {
               return {(std::uint16_t(data[0]) << 8) | data[1],
                       checksum(std::begin(data), std::end(data))};
           }
   
           std::uint8_t host_to_pn532_command(command_code cmd) {
               return static_cast<std::uint8_t>(cmd);
           }
   
           command_code pn532_to_host_command(std::uint8_t cmd) {
               return static_cast<command_code>(cmd - 1);
           }
       }// namespace bits
   }// namespace pn532
   
   #endif//PN532_BITS_ALGO_HPP