Final Fantasy VII (WINDOW.BIN)

/*
FF7 .bin packer/unpacker
Developed by Xeeynamo

The extracted files are GZip deflate files. To recompress them with a format
that the game accepts, compress them back to .gz format, remove the header (it
usually finish with the name of the file with NULL terminating character) and
replace it with the original header used from the game: 1F8B 0800 0000 0000 0003

I tried this on ./INIT/WINDOW.BIN, but I'm sure that it works also for
KERNEL.BIN, SCENE.BIN etc.
*/

#include <stdio.h>
#define MODE_REPACK

size_t CalcFileSize(FILE* f)
{
    size_t prevPos = ftell(f);
    size_t fileSize;
    fseek(f, 0, SEEK_END);
    fileSize = ftell(f);
    fseek(f, prevPos, SEEK_SET);
    return fileSize;
}
int FileToMemory(const char* filename, void** memory, size_t* size)
{
    FILE* f = fopen(filename, "r+b");
    if (f == NULL) return 0;
    *memory = malloc( *size = CalcFileSize(f) );
    fread(*memory, *size, 1, f);
    fclose(f);
    return 1;
}

int main()
{
    typedef struct
    {
        unsigned short compressedSize;
        unsigned short uncompressedSize;
        unsigned short fileType;
    } Header;

    int i;
    char tmpStr[0x100];
    Header* header[256];
    FILE* fOut;
    size_t fileSize;
    FILE* fGz;
    size_t fileGzSize;
    void* data;
    void* datagz;

    if (FileToMemory("WINDOW.BIN", &data, &fileSize) == 0)
        return -1;

#ifdef MODE_REPACK
    fOut = fopen("WINDOW.BIN", "w+b");
#endif // MODE_REPACK

    // Parse data
    header[0] = (Header*)data;
    for(i = 0; header[i]->compressedSize != 0; i++)
    {
        header[i + 1] = (char*)header[i] +
            header[i]->compressedSize + sizeof(Header);

        sprintf(tmpStr, "WINDOW_%i.BIN.GZ", i);
#ifdef MODE_REPACK
        if (FileToMemory(tmpStr, &datagz, &fileGzSize))
        {
            header[i]->compressedSize = fileGzSize;
            fwrite(header[i], sizeof(Header), 1, fOut);
            fwrite(datagz, fileGzSize, 1, fOut);
            free(datagz);
        }
#else
        fGz = fopen(tmpStr, "w+b");
        fwrite(((char*)header[i]) + sizeof(Header),
        header[i]->compressedSize, 1, fGz);
        fclose(fGz);

#endif // MODE_REPACK
    }
#ifdef MODE_REPACK
    short empty = 0;
    fwrite(&empty, 2, 1, fOut);
    fclose(fOut);
#endif // MODE_REPACK

    free(data);
    return 0;
}