Sun, 20 Nov 2022 21:08:36 +0100
use //-style single line comments everywhere
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann 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 met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
29 /**
30 * \file utils.h
31 *
32 * \brief General purpose utility functions.
33 *
34 * \author Mike Becker
35 * \author Olaf Wintermann
36 * \version 3.0
37 * \copyright 2-Clause BSD License
38 */
40 #ifndef UCX_UTILS_H
41 #define UCX_UTILS_H
43 #include "common.h"
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
49 /**
50 * Convenience macro for a for loop that counts from zero to n-1.
51 */
52 #define cx_for_n(varname, n) for (size_t varname = 0 ; (varname) < (n) ; (varname)++)
54 // cx_szmul() definition
56 #if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)
57 #define CX_SZMUL_BUILTIN
59 #if __WORDSIZE == 32
60 /**
61 * Alias for \c __builtin_umul_overflow.
62 *
63 * Performs a multiplication of size_t values and checks for overflow.
64 *
65 * @param a first operand
66 * @param b second operand
67 * @param result a pointer to a size_t, where the result should
68 * be stored
69 * @return zero, if no overflow occurred and the result is correct, non-zero
70 * otherwise
71 */
72 #define cx_szmul(a, b, result) __builtin_umul_overflow(a, b, result)
73 #else // __WORDSIZE != 32
74 /**
75 * Alias for \c __builtin_umull_overflow.
76 *
77 * Performs a multiplication of size_t values and checks for overflow.
78 *
79 * @param a first operand
80 * @param b second operand
81 * @param result a pointer to a size_t, where the result should
82 * be stored
83 * @return zero, if no overflow occurred and the result is correct, non-zero
84 * otherwise
85 */
86 #define cx_szmul(a, b, result) __builtin_umull_overflow(a, b, result)
87 #endif // __WORDSIZE
89 #else // no GNUC or clang bultin
91 /**
92 * Performs a multiplication of size_t values and checks for overflow.
93 *
94 * @param a first operand
95 * @param b second operand
96 * @param result a pointer to a size_t, where the result should
97 * be stored
98 * @return zero, if no overflow occurred and the result is correct, non-zero
99 * otherwise
100 */
101 #define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)
103 /**
104 * Performs a multiplication of size_t values and checks for overflow.
105 *
106 * This is a custom implementation in case there is no compiler builtin
107 * available.
108 *
109 * @param a first operand
110 * @param b second operand
111 * @param result a pointer to a size_t where the result should be stored
112 * @return zero, if no overflow occurred and the result is correct, non-zero
113 * otherwise
114 */
115 int cx_szmul_impl(size_t a, size_t b, size_t *result);
117 #endif
119 #ifdef __cplusplus
120 }
121 #endif
123 #endif // UCX_UTILS_H