int byteswap(const char* filename){
    int ERROR = 1;
    FILE* f = NULL;
    unsigned long recordsize = 2;
    uint8_t* buf = NULL;
    size_t buffersize = 0;
    size_t buffersize_min = 8192;
    //
    // Figure out how big the buffer should be
    //
    buffersize = ((size_t)(recordsize));
    std::cout << buffersize;
    if(buffersize < buffersize_min) {
        buffersize = buffersize_min - (buffersize_min % ((size_t)(recordsize)));
    }

    //
    // Allocate buffer
    //
    //buf = static_cast<uint8_t *>(malloc(buffersize)); //That's a C++ Fix
    buf = malloc(buffersize); //C code
    if(!buf) {
        printf("Error: Out of memoryn");
        return ERROR;
    }

    f = fopen(filename, "r+b");
    if(!f) { return ERROR; }

    for(;;) {
        size_t rec;
        size_t size;
        //
        // Read
        //
        clearerr(f);
        size = fread(buf, 1, buffersize, f);
        if(size == 0) {
            // Check for error
            if(ferror(f)) {
                return ERROR;
            }
            // Otherwise, done
            break;
        }
        //
        // Seek backwards
        //
        if(fseek(f, -((off_t)size), SEEK_CUR) != 0) {
            return ERROR;
        }

        if(size > buffersize) { size = buffersize; }
        if(size < buffersize) {
            //
            // Round up to the next record, filling with zeroes as we go
            //
            size_t extra = size % recordsize;
            if(extra) {
                for(; extra < recordsize; extra++) {
                    buf[size++] = 0;
                }
            }
        }
        //
        // Reverse each record in memory
        //
        for(rec = 0; rec < size; rec += recordsize) {
            size_t a = rec;
            size_t b = rec + recordsize - 1;
            for(; a < b; a++, b--) {
                uint8_t t = buf[a];
                buf[a] = buf[b];
                buf[b] =  t;
            }
        }
        //
        // Write
        //
        if(fwrite(buf, 1, size, f) != size) {
            return ERROR;
        }
        fflush(f);
    }
    printf("%s: Donen", filename);

    if(f != NULL) {
        fclose(f);
    }
    return 0;
}