/* Note: This is copyrighted by Brian Gladman */
/* This is an independent implementation of the encryption algorithm:   */
/*                                                                      */
/*         TwoFish                                                      */
/*                                                                      */
/* which is a candidate algorithm in the Advanced Encryption Standard   */
/* programme of the US National Institute of Standards and Technology.  */
/*                                                                      */
/* Copyright in this implementation is held by Dr B R Gladman but I     */
/* hereby give permission for its free direct or derivative use subject */
/* to acknowledgment of its origin and compliance with any conditions   */
/* that the originators of the algorithm place on its exploitation.     */
/*                                                                      */
/* Dr Brian Gladman (gladman@seven77.demon.co.uk) 14th January 1999     */

/* RCS CHANGE LOG
 * Revision 1.1  2001/01/06 10:46:00  eric
 * Initial checkin of ocotillo.
 *
 * Revision 1.2  1999/09/13 16:05:23  eric
 * changed RC6_H to TWOFISH_H
 *
 * Revision 1.1  1999/09/10 23:24:21  eric
 * Switched from RC6 to Twofish due to patent concerns. RC6 is far superior
 * to TwoFish in terms of code size, elegance, and efficiency on a PII or above,
 * but there is an RC5 patent that MAY apply to RC6, and there are two more
 * patents pending which specifically apply to RC6. If RC6 is selected as the
 * AES standard then these patents will not be a problem (RSA Labs agreed to
 * give up royalties and allow free use of RC6 if selected as the AES standard),
 * but until then we can't use RC6.
 *
 */

/* 1. Standard types for AES cryptography source code               */
#ifndef TWOFISH_H
#define TWOFISH_H 1

typedef unsigned char   u1byte; /* an 8 bit unsigned character type */
typedef unsigned short  u2byte; /* a 16 bit unsigned integer type   */
typedef unsigned int   u4byte; /* a 32 bit unsigned integer type   */

typedef signed char     s1byte; /* an 8 bit signed character type   */
typedef signed short    s2byte; /* a 16 bit signed integer type     */
typedef signed int     s4byte; /* a 32 bit signed integer type     */

/* 2. Standard interface for AES cryptographic routines             */

/* These are all based on 32 bit unsigned values and will therefore */
/* require endian conversions for big-endian architectures          */

#ifdef  __cplusplus
    extern "C"
    {
#endif

    char **cipher_name(void);
    u4byte *set_key(const u4byte in_key[], const u4byte key_len);
    void encrypt(const u4byte in_blk[4], u4byte out_blk[4]);
    void decrypt(const u4byte in_blk[4], u4byte out_blk[4]);

#ifdef  __cplusplus
    };
#endif

/* 3. Basic macros for speeding up generic operations               */

/* Circular rotate of 32 bit values                                 */

#ifdef _MSC_VER

#  include <stdlib.h>
#  pragma intrinsic(_lrotr,_lrotl)
#  define rotr(x,n) _lrotr(x,n)
#  define rotl(x,n) _lrotl(x,n)

#else

#define rotr(x,n)   (((x) >> ((int)(n))) | ((x) << (32 - (int)(n))))
#define rotl(x,n)   (((x) << ((int)(n))) | ((x) >> (32 - (int)(n))))

#endif

/* Invert byte order in a 32 bit variable                           */

#define bswap(x)    (rotl(x, 8) & 0x00ff00ff | rotr(x, 8) & 0xff00ff00)

/* Extract byte from a 32 bit quantity (little endian notation)     */ 

#define byte(x,n)   ((u1byte)((x) >> (8 * n)))

/* For inverting byte order in input/output 32 bit words if needed  */

#ifdef  BLOCK_SWAP
#define BYTE_SWAP
#define WORD_SWAP
#endif

#ifdef  BYTE_SWAP
#define io_swap(x)  bswap(x)
#else
#define io_swap(x)  (x)
#endif

/* For inverting the byte order of input/output blocks if needed    */

#ifdef  WORD_SWAP

#define get_block(x)                            \
    ((u4byte*)(x))[0] = io_swap(in_blk[3]);     \
    ((u4byte*)(x))[1] = io_swap(in_blk[2]);     \
    ((u4byte*)(x))[2] = io_swap(in_blk[1]);     \
    ((u4byte*)(x))[3] = io_swap(in_blk[0])

#define put_block(x)                            \
    out_blk[3] = io_swap(((u4byte*)(x))[0]);    \
    out_blk[2] = io_swap(((u4byte*)(x))[1]);    \
    out_blk[1] = io_swap(((u4byte*)(x))[2]);    \
    out_blk[0] = io_swap(((u4byte*)(x))[3])

#define get_key(x,len)                          \
    ((u4byte*)(x))[4] = ((u4byte*)(x))[5] =     \
    ((u4byte*)(x))[6] = ((u4byte*)(x))[7] = 0;  \
    switch((((len) + 63) / 64)) {               \
    case 2:                                     \
    ((u4byte*)(x))[0] = io_swap(in_key[3]);     \
    ((u4byte*)(x))[1] = io_swap(in_key[2]);     \
    ((u4byte*)(x))[2] = io_swap(in_key[1]);     \
    ((u4byte*)(x))[3] = io_swap(in_key[0]);     \
    break;                                      \
    case 3:                                     \
    ((u4byte*)(x))[0] = io_swap(in_key[5]);     \
    ((u4byte*)(x))[1] = io_swap(in_key[4]);     \
    ((u4byte*)(x))[2] = io_swap(in_key[3]);     \
    ((u4byte*)(x))[3] = io_swap(in_key[2]);     \
    ((u4byte*)(x))[4] = io_swap(in_key[1]);     \
    ((u4byte*)(x))[5] = io_swap(in_key[0]);     \
    break;                                      \
    case 4:                                     \
    ((u4byte*)(x))[0] = io_swap(in_key[7]);     \
    ((u4byte*)(x))[1] = io_swap(in_key[6]);     \
    ((u4byte*)(x))[2] = io_swap(in_key[5]);     \
    ((u4byte*)(x))[3] = io_swap(in_key[4]);     \
    ((u4byte*)(x))[4] = io_swap(in_key[3]);     \
    ((u4byte*)(x))[5] = io_swap(in_key[2]);     \
    ((u4byte*)(x))[6] = io_swap(in_key[1]);     \
    ((u4byte*)(x))[7] = io_swap(in_key[0]);     \
    }

#else

#define get_block(x)                            \
    ((u4byte*)(x))[0] = io_swap(in_blk[0]);     \
    ((u4byte*)(x))[1] = io_swap(in_blk[1]);     \
    ((u4byte*)(x))[2] = io_swap(in_blk[2]);     \
    ((u4byte*)(x))[3] = io_swap(in_blk[3])

#define put_block(x)                            \
    out_blk[0] = io_swap(((u4byte*)(x))[0]);    \
    out_blk[1] = io_swap(((u4byte*)(x))[1]);    \
    out_blk[2] = io_swap(((u4byte*)(x))[2]);    \
    out_blk[3] = io_swap(((u4byte*)(x))[3])

#define get_key(x,len)                          \
    ((u4byte*)(x))[4] = ((u4byte*)(x))[5] =     \
    ((u4byte*)(x))[6] = ((u4byte*)(x))[7] = 0;  \
    switch((((len) + 63) / 64)) {               \
    case 4:                                     \
    ((u4byte*)(x))[6] = io_swap(in_key[6]);     \
    ((u4byte*)(x))[7] = io_swap(in_key[7]);     \
    case 3:                                     \
    ((u4byte*)(x))[4] = io_swap(in_key[4]);     \
    ((u4byte*)(x))[5] = io_swap(in_key[5]);     \
    case 2:                                     \
    ((u4byte*)(x))[0] = io_swap(in_key[0]);     \
    ((u4byte*)(x))[1] = io_swap(in_key[1]);     \
    ((u4byte*)(x))[2] = io_swap(in_key[2]);     \
    ((u4byte*)(x))[3] = io_swap(in_key[3]);     \
    }

#endif

#endif
