| .. default-domain:: cpp |
| |
| .. highlight:: sh |
| |
| ----------- |
| pw_checksum |
| ----------- |
| The ``pw_checksum`` module provides functions for calculating checksums. |
| |
| pw_checksum/ccitt_crc16.h |
| ========================= |
| |
| .. cpp:namespace:: pw::checksum |
| |
| .. cpp:var:: constexpr uint16_t kCcittCrc16DefaultInitialValue = 0xFFFF |
| |
| The default initial value for the CRC16. |
| |
| .. cpp:function:: uint16_t CcittCrc16(span<const std::byte> data, uint16_t initial_value = kCcittCrc16DefaultInitialValue) |
| |
| Calculates the CRC16 of the provided data using polynomial 0x1021, with a |
| default initial value of :cpp:expr:`0xFFFF`. |
| |
| To incrementally calculate a CRC16, use the previous value as the initial |
| value. |
| |
| .. code-block:: cpp |
| |
| uint16_t crc = CcittCrc16(my_data); |
| |
| crc = CcittCrc16(more_data, crc); |
| |
| pw_checksum/crc32.h |
| =================== |
| |
| .. cpp:var:: constexpr uint32_t kCrc32InitialValue = 0xFFFFFFFF |
| |
| The initial value for the CRC32. |
| |
| .. cpp:function:: uint32_t Crc32(span<const std::byte> data) |
| |
| Calculates the initial / one-time CRC32 of the provided data using polynomial |
| 0x4C11DB7, with an initial value of :cpp:expr:`0xFFFFFFFF`. |
| |
| .. code-block:: cpp |
| |
| uint32_t crc = Crc32(my_data); |
| |
| .. cpp:function:: uint32_t Crc32(span<const std::byte> data, uint32_t previous_result) |
| |
| Incrementally append calculation of a CRC32, need to pass in the previous |
| result. |
| |
| .. code-block:: cpp |
| |
| uint32_t crc = Crc32(my_data); |
| crc = Crc32(more_data, crc); |
| |
| Compatibility |
| ============= |
| * C |
| * C++17 |
| |
| Dependencies |
| ============ |
| * ``pw_span`` |