#ifndef CRC32_NOLOOKUP_H
#define CRC32_NOLOOKUP_H

#include <stddef.h>
#include <stdint.h>

/*
 * CRC-32 (IEEE 802.3) implementation
 * Polynomial: 0xEDB88320 (reflected)
 * Initial value: 0xFFFFFFFF
 * Final XOR: 0xFFFFFFFF
 * Input reflected: Yes
 * Output reflected: Yes
 */

static inline uint32_t crc32_ieee(const void *data, size_t len) {
    const uint8_t *p = (const uint8_t *)data;
    uint32_t       crc = 0xFFFFFFFF;

    while (len--) {
        crc ^= *p++;
        for (int i = 0; i < 8; i++) {
            if (crc & 1)
                crc = (crc >> 1) ^ 0xEDB88320;
            else
                crc >>= 1;
        }
    }

    return crc ^ 0xFFFFFFFF;
}

#endif // CRC32_H