Extract music from .vvv file

extract.c

/* 
 * 
 * VVVVVV Music Extractor
 * by Midnoclose
 * 
 * BSD Zero Clause License
 * 
 * Copyright (c) 2021 Midnoclose
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 * 
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define HEADERS 128
#define FILENAME 11

struct header
{
    char name[48];
    int start_UNUSED;
    int size;
    bool valid;
};

int main(int argc, char *argv[]) {
    if (argc != 2) {
        printf("Usage: %s <file.vvv>\n", argv[0]);
        return 1;
    }
    
    struct header files[HEADERS];
    FILE *music, *output;
    char *buffer;
    int i = 0;
    int numfiles = 0;
    
    if ((music = fopen(argv[1], "rb")) == NULL) {
        puts("Unable to open file.");
        return 1;
    }
    
    // list off the files
    do {
        fread(&files[i], sizeof(struct header), 1, music);
        if (!files[i].valid) break;
        printf("%s %dKB\n", files[i].name+FILENAME, files[i].size >> 10); // shift right 10 times to divide by 1024
    } while (files[i++].valid);
    
    numfiles = i - 1;
    
    // seek to actual files
    fseek(music, sizeof(struct header) << 7, SEEK_SET); // shift left 7 times to multiply by HEADERS (128)
    
    for (i = 0; i <= numfiles; i++) {
        if ((output = fopen(files[i].name+FILENAME, "wb")) == NULL) {
            puts("Unable to open file.");
            return 1;
        }
        buffer = malloc(files[i].size);
        fread(buffer, files[i].size, 1, music);
        fwrite(buffer, files[i].size, 1, output);
        free(buffer);
        fclose(output);
    }
    
    fclose(music);
    return 0;
}