// IBM PC Implementation of the DES Cryptographic Algorithm by
// Dr B. R. Gladman (gladman@seven77.demon.co.uk)
//
// Some of the techniques in this DES source code are derived
// from ideas developed by Richard Outerbridge and Eric Young.
// I gratefully acknowledge their contribution.
//
// Note on Bit Numbering. The DES bit numbering is the reverse of that
// used on the intel series processors. Thus to translate between bits
// and numeric values requires a reversal of bit sequences. To achieve
// this for external numbers the initial and final DES permutations and
// the initial key permutation are adjusted to take care of the changed
// bit order. The other changes required are in the calculation of the
// s_box inputs and outputs. The bits numbering reversal on s_box input
// is obtained by reordering the s_box tables. The bit reversal within
// output nibbles is done by reordering the exit permutation.
#ifndef byte
#define byte(x,n) ((unsigned char)((x) >> (8 * (n))))
#endif
#ifndef _MSC_VER
#define rotr(x,n) (((x) >> ((int)(n))) | ((x) << (32 - (int)(n)))) //循环右移
#define rotl(x,n) (((x) << ((int)(n))) | ((x) >> (32 - (int)(n)))) //循环左移
#else
#include <stdlib.h>
#pragma intrinsic(_lrotr,_lrotl)
#define rotr(x,n) _lrotr(x,n)
#define rotl(x,n) _lrotl(x,n)
#endif
//m中是一的位就交换a的高32-n位和b，是0的位不交换
#define bit_swap(a,b,n,m) \
(tt) = (((a) >> (n)) ^ (b)) & (m); \
(b) ^= (tt); (a) ^= ((tt) << (n))
#define ip_old(x,y) \
bit_swap((x),(y), 4, 0x0f0f0f0fL); \
bit_swap((y),(x), 16, 0x0000ffffL); \
bit_swap((x),(y), 2, 0x33333333L); \
bit_swap((y),(x), 8, 0x00ff00ffL); \
bit_swap((x),(y), 1, 0x55555555L); \
(x) = rotl((x), 1); \
(y) = rotl((y), 1)
#define fp_old(x,y) \
(y) = rotr((y), 1); \
(x) = rotr((x), 1); \
bit_swap((x),(y), 1, 0x55555555L); \
bit_swap((y),(x), 8, 0x00ff00ffL); \
bit_swap((x),(y), 2, 0x33333333L); \
bit_swap((y),(x), 16, 0x0000ffffL); \
bit_swap((x),(y), 4, 0x0f0f0f0fL)
//初始置换
#define ip(x,y) \
(x) = rotr((x), 4); \
tt = ((x) ^ (y)) & 0x0f0f0f0fL; \
(y) ^= tt; \
(x) = rotr((x) ^ tt, 12); \
tt = ((y) ^ (x)) & 0xffff0000L; \
(y) ^= tt; \
(x) = rotr((x) ^ tt, 18); \
tt = ((x) ^ (y)) & 0x33333333L; \
(y) ^= tt; \
(x) = rotr((x) ^ tt, 22); \
tt = ((y) ^ (x)) & 0xff00ff00L; \
(y) ^= tt; \
(x) = rotr((x) ^ tt, 9); \
tt = ((x) ^ (y)) & 0x55555555L; \
(x) = rotl((x) ^ tt, 2); \
(y) = rotl((y) ^ tt, 1)
//置换回来
#define fp(x,y) \
(y) = rotr((y), 1); \
(x) = rotr((x), 2); \
tt = ((x) ^ (y)) & 0x55555555L; \
(y) ^= tt; \
(x) = rotl((x) ^ tt, 9); \
tt = ((y) ^ (x)) & 0xff00ff00L; \
(y) ^= tt; \
(x) = rotl((x) ^ tt, 22); \
tt = ((x) ^ (y)) & 0x33333333L; \
(y) ^= tt; \
(x) = rotl((x) ^ tt, 18); \
tt = ((y) ^ (x)) & 0xffff0000L; \
(y) ^= tt; \
(x) = rotl((x) ^ tt, 12); \
tt = ((x) ^ (y)) & 0x0f0f0f0fL; \
(y) ^= tt; \
(x) = rotl((x) ^ tt, 4)
#ifdef BIG_TABLES
//
#define round(x0,x1,ki) \
l1 = (rotr(x1, 4) ^ *(((unsigned long*)key) + ki + 1)); \
l0 = (x1 ^ *(((unsigned long*)key) + ki)); \
x0 ^= sx_tab[0][byte(l0,0)] | sx_tab[1][byte(l1,0)] \
| sx_tab[2][byte(l0,1)] | sx_tab[3][byte(l1,1)] \
| sx_tab[4][byte(l0,2)] | sx_tab[5][byte(l1,2)] \
| sx_tab[6][byte(l0,3)] | sx_tab[7][byte(l1,3)]
#else
#define round(x0,x1,ki) \
l1 = (rotr(x1, 4) ^ *(((unsigned long*)key) + ki + 1)) & 0x3f3f3f3f; \
l0 = (x1 ^ *(((unsigned long*)key) + ki)) & 0x3f3f3f3f; \
x0 ^= sx_tab[0][byte(l0,0)] | sx_tab[1][byte(l1,0)] \
| sx_tab[2][byte(l0,1)] | sx_tab[3][byte(l1,1)] \
| sx_tab[4][byte(l0,2)] | sx_tab[5][byte(l1,2)] \
| sx_tab[6][byte(l0,3)] | sx_tab[7][byte(l1,3)]
#endif
#ifdef __cplusplus
extern "C"
{
void des_ky(void *kval, void *key);
void des_ec(const void *i_blk, void *o_blk, void *key);
void des_dc(const void *i_blk, void *o_blk, void *key);
};
#else
void des_ky(void *kval, void *key);
void des_ec(const void *i_blk, void *o_blk, void *key);
void des_dc(const void *i_blk, void *o_blk, void *key);
#endif
