/** 
 * \file	xtea.c
 * \brief	XTEA implemantation 
 *   copy'n'pasted from http://en.wikipedia.org/wiki/XTEA
 *   and slightly modified
 */
 
#include <stdint.h> 
 

void xtea_enc(uint32_t* dest, uint32_t* v, uint32_t* k) {
    uint32_t v0=v[0], v1=v[1], i;
    uint32_t sum=0, delta=0x9E3779B9;
    for(i=0; i<32; i++) {
        v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
        sum += delta;
        v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
    }
    dest[0]=v0; dest[1]=v1;
}

void xtea_dec(uint32_t* dest, uint32_t* v, uint32_t* k) {
    uint32_t v0=v[0], v1=v[1], i;
    uint32_t sum=0xC6EF3720, delta=0x9E3779B9;
    for(i=0; i<32; i++) {
        v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
        sum -= delta;
        v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
    }
    dest[0]=v0; dest[1]=v1;
}