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 * \copyright 2-Clause BSD License
37 */
38
39 #ifndef UCX_UTILS_H
40 #define UCX_UTILS_H
41
42 #include "common.h"
43
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
47
48 /**
49 * Convenience macro for a for loop that counts from zero to n-1.
50 */
51 #define cx_for_n(varname, n) for (size_t varname = 0 ; (varname) < (n) ; (varname)++)
52
53 /**
54 * Convenience macro for swapping two pointers.
55 */
56 #ifdef __cplusplus
57 #define cx_swap_ptr(left, right) do {auto cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
58 #else
59 #define cx_swap_ptr(left, right) do {void *cx_tmp_swap_var = left; left = right; right = cx_tmp_swap_var;} while(0)
60 #endif
61
62 // cx_szmul() definition
63
64 #if (__GNUC__ >= 5 || defined(__clang__)) && !defined(CX_NO_SZMUL_BUILTIN)
65 #define CX_SZMUL_BUILTIN
66
67 /**
68 * Alias for \c __builtin_mul_overflow.
69 *
70 * Performs a multiplication of size_t values and checks for overflow.
71 *
72 * @param a first operand
73 * @param b second operand
74 * @param result a pointer to a size_t, where the result should
75 * be stored
76 * @return zero, if no overflow occurred and the result is correct, non-zero
77 * otherwise
78 */
79 #define cx_szmul(a, b, result) __builtin_mul_overflow(a, b, result)
80
81 #else // no GNUC or clang bultin
82
83 /**
84 * Performs a multiplication of size_t values and checks for overflow.
85 *
86 * @param a first operand
87 * @param b second operand
88 * @param result a pointer to a size_t, where the result should
89 * be stored
90 * @return zero, if no overflow occurred and the result is correct, non-zero
91 * otherwise
92 */
93 #define cx_szmul(a, b, result) cx_szmul_impl(a, b, result)
94
95 /**
96 * Performs a multiplication of size_t values and checks for overflow.
97 *
98 * This is a custom implementation in case there is no compiler builtin
99 * available.
100 *
101 * @param a first operand
102 * @param b second operand
103 * @param result a pointer to a size_t where the result should be stored
104 * @return zero, if no overflow occurred and the result is correct, non-zero
105 * otherwise
106 */
107 int cx_szmul_impl(size_t a, size_t b, size_t *result);
108
109 #endif // cx_szmul
110
111
112 /**
113 * Reads data from a stream and writes it to another stream.
114 *
115 * @param src the source stream
116 * @param dest the destination stream
117 * @param rfnc the read function
118 * @param wfnc the write function
119 * @param buf a pointer to the copy buffer or \c NULL if a buffer
120 * shall be implicitly created on the heap
121 * @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
122 * set this to zero to let the implementation decide
123 * @param n the maximum number of bytes that shall be copied.
124 * If this is larger than \p bufsize, the content is copied over multiple
125 * iterations.
126 * @return the total number of bytes copied
127 */
128 __attribute__((__nonnull__(1, 2, 3, 4)))
129 size_t cx_stream_bncopy(
130 void *src,
131 void *dest,
132 cx_read_func rfnc,
133 cx_write_func wfnc,
134 char *buf,
135 size_t bufsize,
136 size_t n
137 );
138
139 /**
140 * Reads data from a stream and writes it to another stream.
141 *
142 * @param src the source stream
143 * @param dest the destination stream
144 * @param rfnc the read function
145 * @param wfnc the write function
146 * @param buf a pointer to the copy buffer or \c NULL if a buffer
147 * shall be implicitly created on the heap
148 * @param bufsize the size of the copy buffer - if \p buf is \c NULL you can
149 * set this to zero to let the implementation decide
150 * @return total number of bytes copied
151 */
152 #define cx_stream_bcopy(src, dest, rfnc, wfnc, buf, bufsize) \
153 cx_stream_bncopy(src, dest, rfnc, wfnc, buf, bufsize, SIZE_MAX)
154
155 /**
156 * Reads data from a stream and writes it to another stream.
157 *
158 * The data is temporarily stored in a stack allocated buffer.
159 *
160 * @param src the source stream
161 * @param dest the destination stream
162 * @param rfnc the read function
163 * @param wfnc the write function
164 * @param n the maximum number of bytes that shall be copied.
165 * @return total number of bytes copied
166 */
167 __attribute__((__nonnull__))
168 size_t cx_stream_ncopy(
169 void *src,
170 void *dest,
171 cx_read_func rfnc,
172 cx_write_func wfnc,
173 size_t n
174 );
175
176 /**
177 * Reads data from a stream and writes it to another stream.
178 *
179 * The data is temporarily stored in a stack allocated buffer.
180 *
181 * @param src the source stream
182 * @param dest the destination stream
183 * @param rfnc the read function
184 * @param wfnc the write function
185 * @return total number of bytes copied
186 */
187 #define cx_stream_copy(src, dest, rfnc, wfnc) \
188 cx_stream_ncopy(src, dest, rfnc, wfnc, SIZE_MAX)
189
190 #ifdef __cplusplus
191 }
192 #endif
193
194 #endif // UCX_UTILS_H
195