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 */
28
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 */
39
40 #ifndef UCX_UTILS_H
41 #define UCX_UTILS_H
42
43 #include "common.h"
44
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48
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)++)
53
54 /**
55 * Convenience macro for swapping two pointers.
56 */
57 #ifdef __cplusplus
58 #define cx_swap_ptr(left, right) do {auto cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
59 #else
60 #define cx_swap_ptr(left, right) do {void *cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
61 #endif
62
63 // cx_szmul() definition
64
65 #if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)
66 #define CX_SZMUL_BUILTIN
67
68 /**
69 * Alias for \c __builtin_mul_overflow.
70 *
71 * Performs a multiplication of size_t values and checks for overflow.
72 *
73 * @param a first operand
74 * @param b second operand
75 * @param result a pointer to a size_t, where the result should
76 * be stored
77 * @return zero, if no overflow occurred and the result is correct, non-zero
78 * otherwise
79 */
80 #define cx_szmul(a, b, result) __builtin_mul_overflow(a, b, result)
81
82 #else // no GNUC or clang bultin
83
84 /**
85 * Performs a multiplication of size_t values and checks for overflow.
86 *
87 * @param a first operand
88 * @param b second operand
89 * @param result a pointer to a size_t, where the result should
90 * be stored
91 * @return zero, if no overflow occurred and the result is correct, non-zero
92 * otherwise
93 */
94 #define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)
95
96 /**
97 * Performs a multiplication of size_t values and checks for overflow.
98 *
99 * This is a custom implementation in case there is no compiler builtin
100 * available.
101 *
102 * @param a first operand
103 * @param b second operand
104 * @param result a pointer to a size_t where the result should be stored
105 * @return zero, if no overflow occurred and the result is correct, non-zero
106 * otherwise
107 */
108 int cx_szmul_impl(size_t a, size_t b, size_t *result);
109
110 #endif // cx_szmul
111
112
113 /**
114 * Reads data from a stream and writes it to another stream.
115 *
116 * @param src the source stream
117 * @param dest the destination stream
118 * @param rfnc the read function
119 * @param wfnc the write function
120 * @param buf a pointer to the copy buffer or \c NULL if a buffer
121 * shall be implicitly created on the heap
122 * @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
123 * set this to zero to let the implementation decide
124 * @param n the maximum number of bytes that shall be copied.
125 * If this is larger than \p bufsize, the content is copied over multiple
126 * iterations.
127 * @return the total number of bytes
opied
128 */
129 __attribute__((__nonnull__(1, 2, 3, 4)))
130 size_t cx_stream_bncopy(
131 void *src,
132 void *dest,
133 cx_read_func rfnc,
134 cx_write_func wfnc,
135 char *buf,
136 size_t bufsize,
137 size_t n
138 );
139
140 /**
141 * Reads data from a stream and writes it to another stream.
142 *
143 * @param src the source stream
144 * @param dest the destination stream
145 * @param rfnc the read function
146 * @param wfnc the write function
147 * @param buf a pointer to the copy buffer or \c NULL if a buffer
148 * shall be implicitly created on the heap
149 * @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
150 * set this to zero to let the implementation decide
151 * @return total number of bytes copied
152 */
153 #define cx_stream_bcopy(src, dest, rfnc, wfnc, buf, bufsize) \
154 cx_stream_bncopy(src, dest, rfnc, wfnc, buf, bufsize, SIZE_MAX)
155
156 /**
157 * Reads data from a stream and writes it to another stream.
158 *
159 * The data is temporarily stored in a stack allocated buffer.
160 *
161 * @param src the source stream
162 * @param dest the destination stream
163 * @param rfnc the read function
164 * @param wfnc the write function
165 * @param n the maximum number of bytes that shall be copied.
166 * @return total number of bytes copied
167 */
168 __attribute__((__nonnull__))
169 size_t cx_stream_ncopy(
170 void *src,
171 void *dest,
172 cx_read_func rfnc,
173 cx_write_func wfnc,
174 size_t n
175 );
176
177 /**
178 * Reads data from a stream and writes it to another stream.
179 *
180 * The data is temporarily stored in a stack allocated buffer.
181 *
182 * @param src the source stream
183 * @param dest the destination stream
184 * @param rfnc the read function
185 * @param wfnc the write function
186 * @return total number of bytes copied
187 */
188 #define cx_stream_copy(src, dest, rfnc, wfnc) \
189 cx_stream_ncopy(src, dest, rfnc, wfnc, SIZE_MAX)
190
191 #ifdef __cplusplus
192 }
193 #endif
194
195 #endif // UCX_UTILS_H
196