CRC-16 / OPENSAFETY-B

/* 
 * Model: CRC-16 / OPENSAFETY-B (16-bit)
 * Poly: 0x755B, Init: 0x0000, XorOut: 0x0000
 * CRC Table C Source Code & Lookup Table Generator
 */
#include <stdint.h>
#include <stddef.h>

const uint16_t crc_table[256] = {
  0x0000, 0x755B, 0xEAB6, 0x9FED, 0xA037, 0xD56C, 0x4A81, 0x3FDA, 
  0x3535, 0x406E, 0xDF83, 0xAAD8, 0x9502, 0xE059, 0x7FB4, 0x0AEF, 
  0x6A6A, 0x1F31, 0x80DC, 0xF587, 0xCA5D, 0xBF06, 0x20EB, 0x55B0, 
  0x5F5F, 0x2A04, 0xB5E9, 0xC0B2, 0xFF68, 0x8A33, 0x15DE, 0x6085, 
  0xD4D4, 0xA18F, 0x3E62, 0x4B39, 0x74E3, 0x01B8, 0x9E55, 0xEB0E, 
  0xE1E1, 0x94BA, 0x0B57, 0x7E0C, 0x41D6, 0x348D, 0xAB60, 0xDE3B, 
  0xBEBE, 0xCBE5, 0x5408, 0x2153, 0x1E89, 0x6BD2, 0xF43F, 0x8164, 
  0x8B8B, 0xFED0, 0x613D, 0x1466, 0x2BBC, 0x5EE7, 0xC10A, 0xB451, 
  0xDCF3, 0xA9A8, 0x3645, 0x431E, 0x7CC4, 0x099F, 0x9672, 0xE329, 
  0xE9C6, 0x9C9D, 0x0370, 0x762B, 0x49F1, 0x3CAA, 0xA347, 0xD61C, 
  0xB699, 0xC3C2, 0x5C2F, 0x2974, 0x16AE, 0x63F5, 0xFC18, 0x8943, 
  0x83AC, 0xF6F7, 0x691A, 0x1C41, 0x239B, 0x56C0, 0xC92D, 0xBC76, 
  0x0827, 0x7D7C, 0xE291, 0x97CA, 0xA810, 0xDD4B, 0x42A6, 0x37FD, 
  0x3D12, 0x4849, 0xD7A4, 0xA2FF, 0x9D25, 0xE87E, 0x7793, 0x02C8, 
  0x624D, 0x1716, 0x88FB, 0xFDA0, 0xC27A, 0xB721, 0x28CC, 0x5D97, 
  0x5778, 0x2223, 0xBDCE, 0xC895, 0xF74F, 0x8214, 0x1DF9, 0x68A2, 
  0xCCBD, 0xB9E6, 0x260B, 0x5350, 0x6C8A, 0x19D1, 0x863C, 0xF367, 
  0xF988, 0x8CD3, 0x133E, 0x6665, 0x59BF, 0x2CE4, 0xB309, 0xC652, 
  0xA6D7, 0xD38C, 0x4C61, 0x393A, 0x06E0, 0x73BB, 0xEC56, 0x990D, 
  0x93E2, 0xE6B9, 0x7954, 0x0C0F, 0x33D5, 0x468E, 0xD963, 0xAC38, 
  0x1869, 0x6D32, 0xF2DF, 0x8784, 0xB85E, 0xCD05, 0x52E8, 0x27B3, 
  0x2D5C, 0x5807, 0xC7EA, 0xB2B1, 0x8D6B, 0xF830, 0x67DD, 0x1286, 
  0x7203, 0x0758, 0x98B5, 0xEDEE, 0xD234, 0xA76F, 0x3882, 0x4DD9, 
  0x4736, 0x326D, 0xAD80, 0xD8DB, 0xE701, 0x925A, 0x0DB7, 0x78EC, 
  0x104E, 0x6515, 0xFAF8, 0x8FA3, 0xB079, 0xC522, 0x5ACF, 0x2F94, 
  0x257B, 0x5020, 0xCFCD, 0xBA96, 0x854C, 0xF017, 0x6FFA, 0x1AA1, 
  0x7A24, 0x0F7F, 0x9092, 0xE5C9, 0xDA13, 0xAF48, 0x30A5, 0x45FE, 
  0x4F11, 0x3A4A, 0xA5A7, 0xD0FC, 0xEF26, 0x9A7D, 0x0590, 0x70CB, 
  0xC49A, 0xB1C1, 0x2E2C, 0x5B77, 0x64AD, 0x11F6, 0x8E1B, 0xFB40, 
  0xF1AF, 0x84F4, 0x1B19, 0x6E42, 0x5198, 0x24C3, 0xBB2E, 0xCE75, 
  0xAEF0, 0xDBAB, 0x4446, 0x311D, 0x0EC7, 0x7B9C, 0xE471, 0x912A, 
  0x9BC5, 0xEE9E, 0x7173, 0x0428, 0x3BF2, 0x4EA9, 0xD144, 0xA41F
};

uint16_t calculate_crc(const uint8_t *data, size_t length) {
    uint16_t crc = 0x0000;
    for (size_t i = 0; i < length; i++) {
        #if 0
        uint8_t idx = (uint8_t)(crc ^ data[i]);
        crc = (crc >> 8) ^ crc_table[idx];
        #else
        uint8_t idx = (uint8_t)((crc >> 8) ^ data[i]);
        crc = (crc << 8) ^ crc_table[idx];
        #endif
    }
    return crc ^ 0x0000;
}