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

struct initrd_header {
    unsigned char magic;
    char name[64];
    unsigned int offset;
    unsigned int length;
};

int main(char argc, char **argv) {
    int nheaders = (argc - 1) / 2;
    struct initrd_header headers[64];
    printf("size of header: %d\n", (int) sizeof(struct initrd_header));
    unsigned int off = sizeof(struct initrd_header) * 64 + sizeof(int);

    for (int i = 0; i < nheaders; i++) {
        printf("writing file %s->%s at 0x%x\n", argv[i * 2 + 1], argv[i * 2 + 2], off);
        strcpy(headers[i].name, argv[i * 2 + 2]);
        headers[i].name[strlen(argv[i * 2 + 2])] = '\0';
        headers[i].offset = off;
        FILE *stream = fopen(argv[i * 2 + 1], "r");
        if (stream == 0) {
            printf("Error: file not found: %s\n", argv[i * 2 + 1]);
            return 1;
        }
        fseek(stream, 0, SEEK_END);
        headers[i].length = ftell(stream);
        off += headers[i].length;
        fclose(stream);
        headers[i].magic = 0xBF;
    }

    FILE *wstream = fopen("./initrd.img", "w");
    unsigned char *data = (unsigned char *) malloc(off);
    fwrite(&nheaders, sizeof(int), 1, wstream);
    fwrite(headers, sizeof(struct initrd_header), 64, wstream);

    for (int i = 0; i < nheaders; i++) {
        FILE *stream = fopen(argv[i * 2 + 1], "r");
        unsigned char *buf = (unsigned char *) malloc(headers[i].length);
        fread(buf, 1, headers[i].length, stream);
        fwrite(buf, 1, headers[i].length, wstream);
        fclose(stream);
        free(buf);
    }

    fclose(wstream);
    free(data);

    return 0;
}