Ex-Ranza bitswap

#include <cstdio>
#include <algorithm>

unsigned char rom[0x100000];
int count[256];
int idx[256];

char str[] = "hdebcgfa";

bool cmp(int a, int b)
{
    return count[a]<count[b];
}

int convert(int a)
{
    int r = 0;
    for (int i=0; i<8; ++i)
    {
        if (a&(1<<(7-i)))
            r|=(1<<(7-(strchr(str,'a'+i)-str)));
    }
    return r;
}

char str2[] = "akcdspgoilbjmnhfqret";

int convert2(int a)
{
    int r = 0;
    for (int i=0; i<20; ++i)
    {
        if (a&(1<<(19-(strchr(str2,'a'+i)-str2))))
            r|=(1<<(19-i));
    }
    return r;
}

int main()
{
    FILE *f = fopen("Ex-Ranza.bin","rb");
    fread(rom,1,sizeof(rom),f);
    fclose(f);

    for (int i=0; i<sizeof(rom); ++i)
    {
        rom[i] = convert(rom[i]);
        ++count[rom[i]];
    }

    f = fopen("Ex-Ranza__.bin","wb");
    for (int i=0; i<sizeof(rom); ++i)
    {
        unsigned char q = rom[convert2(i)];
        fwrite(&q,1,1,f);
    }
    fclose(f);

    for (int i=0; i<256; ++i)
        idx[i]=i;
    std::sort(idx,idx+256, cmp);
    for (int j=0; j<256; ++j)
    {
        int i = idx[j];
        printf("%02X: %d\n",i,count[i]);
    }
    return 0;
}