#include <stdio.h>

#ifndef WIN32
/* We use memory mapping in Linux. It's fast. */
#include <sys/mman.h>
#define USE_MMAP 1
#endif


static unsigned char* ROM = NULL;
static unsigned known_romsize;

static void LoadROM(FILE *fp)
{
    fprintf(stderr, "Loading ROM...");
    unsigned hdrskip = 0;

    fseek(fp, 0, SEEK_END);
    unsigned romsize = ftell(fp);
    hdrskip = romsize & 1023;
    romsize &= ~1023;
    romsize -= hdrskip;
    
    fprintf(stderr, " $%X bytes...", romsize);
    ROM = NULL;
#ifdef USE_MMAP
    /* This takes about 0.0001s on my computer over nfs */
    ROM = (unsigned char *)mmap(NULL, romsize, PROT_READ, MAP_PRIVATE, fileno(fp), hdrskip);
#endif
    /* mmap could have failed, so revert to reading */
    if(ROM == NULL || ROM == (unsigned char*)(-1))
    {
        /* This takes about 5s on my computer over nfs */
        ROM = (unsigned char*)malloc(romsize);
        fseek(fp, hdrskip, SEEK_SET);
        fread(ROM, 1, romsize, fp);
    }
    else
        fprintf(stderr, " memmap succesful (%p),", (const void *)ROM);
    fprintf(stderr, " done");
    
    known_romsize = romsize;
    
    fprintf(stderr, "\n");
}

static void PokeROM()
{
    printf("Game name: %.23s\n", ROM+0x7FC0);
}

int main(void)
{
    FILE* fp = fopen("smw.smc", "rb");
    if(!fp)
    {
        perror("smw.smc");
        return -1;
    }
    LoadROM(fp);
    fclose(fp); // after the file has been mmapped, fd isn't needed anymore!
    
    PokeROM();
}