enum { CRC_TABLE_SIZE = 0x100 }; static inline uint32_t crc_reflect(uint32_t input) { uint32_t reflected = 0; for (int i = 0; i < 32; i++) { reflected <<= 1; reflected |= input & 1; input >>= 1; } return reflected; } static inline void crc_be_fill_table(uint32_t *table, uint32_t polynomial) { const uint32_t lsb = 1 << 31; uint32_t poly = polynomial; for (int c = 0; c < CRC_TABLE_SIZE; c++) { uint32_t v = c << 24; for (int i = 0; i < 8; i++) { if (v & lsb) { v <<= 1; v ^= poly; } else { v <<= 1; } } *table++ = v; } } static inline void crc_le_fill_table(uint32_t *table, uint32_t polynomial) { const uint32_t lsb = 1; uint32_t poly = crc_reflect(polynomial); for (int c = 0; c < CRC_TABLE_SIZE; c++) { uint32_t v = c; for (int i = 0; i < 8; i++) { if (v & lsb) { v >>= 1; v ^= poly; } else { v >>= 1; } } *table++ = v; } } static inline void crc_be_cycle(uint32_t *table, uint32_t *remainder, uint8_t c) { const uint8_t i = (*remainder >> 24) ^ c; *remainder = (*remainder << 8) ^ table[i]; } static inline void crc_le_cycle(uint32_t *table, uint32_t *remainder, uint8_t c) { const uint8_t i = (*remainder & 0xFF) ^ c; *remainder = (*remainder >> 8) ^ table[i]; }