chiark / gitweb /
Static buffers: Provide new rotating static buffer macros
[secnet] / u64.h
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1/* uint64_t-like operations that work even on hosts lacking uint64_t
2
3 Copyright (C) 2006, 2009, 2010 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17
18/* Written by Paul Eggert. */
19
20#include <stddef.h>
21#include <stdint.h>
22
23/* Return X rotated left by N bits, where 0 < N < 64. */
24#define u64rol(x, n) u64or (u64shl (x, n), u64shr (x, 64 - n))
25
26#ifdef UINT64_MAX
27
28/* Native implementations are trivial. See below for comments on what
29 these operations do. */
30typedef uint64_t u64;
31# define u64hilo(hi, lo) ((u64) (((u64) (hi) << 32) + (lo)))
32# define u64init(hi, lo) u64hilo (hi, lo)
33# define u64lo(x) ((u64) (x))
34# define u64lt(x, y) ((x) < (y))
35# define u64and(x, y) ((x) & (y))
36# define u64or(x, y) ((x) | (y))
37# define u64xor(x, y) ((x) ^ (y))
38# define u64plus(x, y) ((x) + (y))
39# define u64shl(x, n) ((x) << (n))
40# define u64shr(x, n) ((x) >> (n))
41
42#else
43
44/* u64 is a 64-bit unsigned integer value.
45 u64init (HI, LO), is like u64hilo (HI, LO), but for use in
46 initializer contexts. */
47# ifdef WORDS_BIGENDIAN
48typedef struct { uint32_t hi, lo; } u64;
49# define u64init(hi, lo) { hi, lo }
50# else
51typedef struct { uint32_t lo, hi; } u64;
52# define u64init(hi, lo) { lo, hi }
53# endif
54
55/* Given the high and low-order 32-bit quantities HI and LO, return a u64
56 value representing (HI << 32) + LO. */
57static inline u64
58u64hilo (uint32_t hi, uint32_t lo)
59{
60 u64 r;
61 r.hi = hi;
62 r.lo = lo;
63 return r;
64}
65
66/* Return a u64 value representing LO. */
67static inline u64
68u64lo (uint32_t lo)
69{
70 u64 r;
71 r.hi = 0;
72 r.lo = lo;
73 return r;
74}
75
76/* Return X < Y. */
77static inline int
78u64lt (u64 x, u64 y)
79{
80 return x.hi < y.hi || (x.hi == y.hi && x.lo < y.lo);
81}
82
83/* Return X & Y. */
84static inline u64
85u64and (u64 x, u64 y)
86{
87 u64 r;
88 r.hi = x.hi & y.hi;
89 r.lo = x.lo & y.lo;
90 return r;
91}
92
93/* Return X | Y. */
94static inline u64
95u64or (u64 x, u64 y)
96{
97 u64 r;
98 r.hi = x.hi | y.hi;
99 r.lo = x.lo | y.lo;
100 return r;
101}
102
103/* Return X ^ Y. */
104static inline u64
105u64xor (u64 x, u64 y)
106{
107 u64 r;
108 r.hi = x.hi ^ y.hi;
109 r.lo = x.lo ^ y.lo;
110 return r;
111}
112
113/* Return X + Y. */
114static inline u64
115u64plus (u64 x, u64 y)
116{
117 u64 r;
118 r.lo = x.lo + y.lo;
119 r.hi = x.hi + y.hi + (r.lo < x.lo);
120 return r;
121}
122
123/* Return X << N. */
124static inline u64
125u64shl (u64 x, int n)
126{
127 u64 r;
128 if (n < 32)
129 {
130 r.hi = (x.hi << n) | (x.lo >> (32 - n));
131 r.lo = x.lo << n;
132 }
133 else
134 {
135 r.hi = x.lo << (n - 32);
136 r.lo = 0;
137 }
138 return r;
139}
140
141/* Return X >> N. */
142static inline u64
143u64shr (u64 x, int n)
144{
145 u64 r;
146 if (n < 32)
147 {
148 r.hi = x.hi >> n;
149 r.lo = (x.hi << (32 - n)) | (x.lo >> n);
150 }
151 else
152 {
153 r.hi = 0;
154 r.lo = x.hi >> (n - 32);
155 }
156 return r;
157}
158
159#endif