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useful.h
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1 /*
2 *
3 * Copyright 2015, Google Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met:
9 *
10 * * Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * * Redistributions in binary form must reproduce the above
13 * copyright notice, this list of conditions and the following disclaimer
14 * in the documentation and/or other materials provided with the
15 * distribution.
16 * * Neither the name of Google Inc. nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 */
33
34 #ifndef GRPC_SUPPORT_USEFUL_H
35 #define GRPC_SUPPORT_USEFUL_H
36
37 /* useful macros that don't belong anywhere else */
38
39 #define GPR_MIN(a, b) ((a) < (b) ? (a) : (b))
40 #define GPR_MAX(a, b) ((a) > (b) ? (a) : (b))
41 #define GPR_CLAMP(a, min, max) ((a) < (min) ? (min) : (a) > (max) ? (max) : (a))
42 /* rotl, rotr assume x is unsigned */
43 #define GPR_ROTL(x, n) (((x) << (n)) | ((x) >> (sizeof(x) * 8 - (n))))
44 #define GPR_ROTR(x, n) (((x) >> (n)) | ((x) << (sizeof(x) * 8 - (n))))
45
46 #define GPR_ARRAY_SIZE(array) (sizeof(array) / sizeof(*(array)))
47
48 #define GPR_SWAP(type, a, b) \
49 do { \
50 type x = a; \
51 a = b; \
52 b = x; \
53 } while (0)
54
56 #define GPR_BITSET(i, n) ((*(i)) |= (1u << (n)))
57
59 #define GPR_BITCLEAR(i, n) ((*(i)) &= ~(1u << (n)))
60
62 #define GPR_BITGET(i, n) (((i) & (1u << (n))) != 0)
63
64 #define GPR_INTERNAL_HEXDIGIT_BITCOUNT(x) \
65 ((x) - (((x) >> 1) & 0x77777777) - (((x) >> 2) & 0x33333333) - \
66 (((x) >> 3) & 0x11111111))
67
69 #define GPR_BITCOUNT(i) \
70 (((GPR_INTERNAL_HEXDIGIT_BITCOUNT(i) + \
71 (GPR_INTERNAL_HEXDIGIT_BITCOUNT(i) >> 4)) & \
72 0x0f0f0f0f) % \
73 255)
74
75 #endif /* GRPC_SUPPORT_USEFUL_H */