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

#define rot( x, k ) (((x)<<(k))|((x)>>(32-(k))))

typedef unsigned int u4;
struct triple { u4 a, b, c; };

int main() {
	const u4 rot1 = 7, rot2 = 14, rot3 = 29;
	triple tgt, pre;
	
	tgt.a = 0x12345678;
	tgt.b = 0x87654321;
	tgt.c = 0xabcdef30;

	pre.a = 0xabababab;
	pre.b = 0xdededede;
	pre.c = 0xdeadbeef;

	for ( u4 test = 0; test < 0xffffffff; test++ ) {
		u4 data0 = ( ( tgt.a ^ rot( ( ( tgt.b ^ rot( ( tgt.c - ( pre.c ^ rot( test, rot1 ) ) ), rot3 ) ) - pre.b ), rot2 ) ) - pre.a );
		
		if ( data0 == test ) {
			u4 data2 = ( tgt.c - ( pre.c ^ rot( data0, rot1 ) ) );
			u4 data1 = ( tgt.b ^ rot( data2, rot3 ) ) - pre.b;
			
			triple post = pre;
			u4 t = data0; post.a += t; t = rot(t, rot1); post.c ^= t;
			t = data1; post.b += t; t = rot(t, rot2); post.a ^= t;
			t = data2; post.c += t; t = rot(t, rot3); post.b ^= t;
			printf( "target: %x %x %x, result: %x %x %x (data: %x %x %x)\n", 
				tgt.a, tgt.b, tgt.c, 
				post.a, post.b, post.c,
				data0, data1, data2 );
		}
	}
	
	return ( 0 );
}

/*
	t = data[0]; a += t; t = rotate(t, const1); c ^= t;
	t = data[1]; b += t; t = rotate(t, const2); a ^= t;
	t = data[2]; c += t; t = rotate(t, const3); b ^= t;

	data[0] = ( A ^ rotate(data[1],rot2) ) - a
	data[1] = ( B ^ rotate(data[2],rot3) ) - b
	data[2] = ( C - ( c ^ rotate(data[0],rot1) ) )
*/