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macros.h
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1 /* macros.h
2  *
3  */
4 
5 /* nettle, low-level cryptographics library
6  *
7  * Copyright (C) 2001 Niels Möller
8  *
9  * The nettle library is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or (at your
12  * option) any later version.
13  *
14  * The nettle library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public License
20  * along with the nettle library; see the file COPYING.LIB. If not, write to
21  * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
22  * MA 02111-1307, USA.
23  */
24 
25 #ifndef NETTLE_MACROS_H_INCLUDED
26 #define NETTLE_MACROS_H_INCLUDED
27 
28 /* Reads a 32-bit integer, in network, big-endian, byte order */
29 #define READ_UINT32(p) \
30 ( (((uint32_t) (p)[0]) << 24) \
31  | (((uint32_t) (p)[1]) << 16) \
32  | (((uint32_t) (p)[2]) << 8) \
33  | ((uint32_t) (p)[3]))
34 
35 #define WRITE_UINT32(p, i) \
36 do { \
37  (p)[0] = ((i) >> 24) & 0xff; \
38  (p)[1] = ((i) >> 16) & 0xff; \
39  (p)[2] = ((i) >> 8) & 0xff; \
40  (p)[3] = (i) & 0xff; \
41 } while(0)
42 
43 /* Analogous macros, for 24 and 16 bit numbers */
44 #define READ_UINT24(p) \
45 ( (((uint32_t) (p)[0]) << 16) \
46  | (((uint32_t) (p)[1]) << 8) \
47  | ((uint32_t) (p)[2]))
48 
49 #define WRITE_UINT24(p, i) \
50 do { \
51  (p)[0] = ((i) >> 16) & 0xff; \
52  (p)[1] = ((i) >> 8) & 0xff; \
53  (p)[2] = (i) & 0xff; \
54 } while(0)
55 
56 #define READ_UINT16(p) \
57 ( (((uint32_t) (p)[0]) << 8) \
58  | ((uint32_t) (p)[1]))
59 
60 #define WRITE_UINT16(p, i) \
61 do { \
62  (p)[0] = ((i) >> 8) & 0xff; \
63  (p)[1] = (i) & 0xff; \
64 } while(0)
65 
66 /* And the other, little-endian, byteorder */
67 #define LE_READ_UINT32(p) \
68 ( (((uint32_t) (p)[3]) << 24) \
69  | (((uint32_t) (p)[2]) << 16) \
70  | (((uint32_t) (p)[1]) << 8) \
71  | ((uint32_t) (p)[0]))
72 
73 #define LE_WRITE_UINT32(p, i) \
74 do { \
75  (p)[3] = ((i) >> 24) & 0xff; \
76  (p)[2] = ((i) >> 16) & 0xff; \
77  (p)[1] = ((i) >> 8) & 0xff; \
78  (p)[0] = (i) & 0xff; \
79 } while(0)
80 
81 /* Analogous macros, for 16 bit numbers */
82 #define LE_READ_UINT16(p) \
83  ( (((uint32_t) (p)[1]) << 8) \
84  | ((uint32_t) (p)[0]))
85 
86 #define LE_WRITE_UINT16(p, i) \
87  do { \
88  (p)[1] = ((i) >> 8) & 0xff; \
89  (p)[0] = (i) & 0xff; \
90  } while(0)
91 
92 /* Macro to make it easier to loop over several blocks. */
93 #define FOR_BLOCKS(length, dst, src, blocksize) \
94  assert( !((length) % (blocksize))); \
95  for (; (length); ((length) -= (blocksize), \
96  (dst) += (blocksize), \
97  (src) += (blocksize)) )
98 
99 #endif /* NETTLE_MACROS_H_INCLUDED */
100