/*
 * Copyright (c) Souldbminer, Lightos_ and Horizon OC Contributors
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 */

#pragma once
#include <stdio.h>
#include <stdint.h>

uint32_t crc32(const uint8_t *data, size_t length) {
    uint32_t crc = 0xFFFFFFFF;
    
    for (size_t i = 0; i < length; i++) {
        crc ^= data[i];
        for (int j = 0; j < 8; j++) {
            crc = (crc >> 1) ^ (0xEDB88320 & -(crc & 1));
        }
    }
    return ~crc;
}

uint32_t checksum_file(const char *filename) {
    FILE *file = fopen(filename, "rb");
    if (!file) {
        perror("[crc32] Error opening file");
        return 0;
    }
    
    uint8_t buffer[1024];
    uint32_t crc = 0xFFFFFFFF;
    size_t bytes_read;
    
    while ((bytes_read = fread(buffer, 1, sizeof(buffer), file)) > 0) {
        for (size_t i = 0; i < bytes_read; i++) {
            crc ^= buffer[i];
            for (int j = 0; j < 8; j++) {
                crc = (crc >> 1) ^ (0xEDB88320 & -(crc & 1));
            }
        }
    }
    
    fclose(file);
    return ~crc;
}