#include <cstdio>
#include <cstdlib>

#include <ctime>
#include <climits>

int main(int argc, char **argv) {
    const char *filename = "a.bin";
    int bytes_count = 256;

    if (argc > 1)
        filename = argv[1];
    
    if (argc > 2)
        bytes_count = atoi(argv[2]);

    auto hex_file = fopen(filename, "wb");

    if (hex_file == NULL) {
        return -1;
    }

    srand(time(NULL));

    constexpr int chunk_size = 0x400;
    unsigned char buffer[chunk_size];
    for (int total_bytes = bytes_count; chunk_size < total_bytes; total_bytes -= chunk_size) {
        memset(buffer, 0, chunk_size);

        for (int i = 0; i < chunk_size; ++ i) {
            buffer[i] = rand() % UCHAR_MAX;
        }

        fwrite(buffer, chunk_size, 1, hex_file);
    }

    memset(buffer, 0, chunk_size);
    for (int i = 0; i < bytes_count % chunk_size; ++ i) {
        buffer[i] = rand() % UCHAR_MAX;
    }
    fwrite(buffer, bytes_count % chunk_size, 1, hex_file);

    fclose(hex_file);

    return 0;
}