ついでにDecoder
#include <stdio.h>
unsigned char f[256];size_t l,r=0xffffffff,c,q,z,u[257],i;main(int a,char**v){
FILE*n=fopen(v[1],"rb"),*o=fopen(v[2],"wb");fread(&z,4,1,n);fread(f,1,256,n);
for(i=0;i<256;i++)u[i+1]=u[i]+f[i];for(i=0;i<4;i++)c=c<<8|fgetc(n);while(z){r
/=u[256];q=(c-l)/r;if(q>=u[256])return;for(i=0;i<256&&q>=u[i+1];i++);if(i>=256
)break;fputc(i,o);z--;l+=u[i]*r;r*=f[i];while((l^l+r)<1<<24||r<1<<16&&((r=~l+1
&65535),1)){c=c<<8|fgetc(n);r<<=8;l<<=8;}}}