lavu: add CHK_OFFS as AV_CHECK_OFFSET to check struct member offsets
[libav.git] / libavutil / internal.h
1 /*
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of Libav.
5 *
6 * Libav is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * Libav is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * common internal API header
24 */
25
26 #ifndef AVUTIL_INTERNAL_H
27 #define AVUTIL_INTERNAL_H
28
29 #if !defined(DEBUG) && !defined(NDEBUG)
30 # define NDEBUG
31 #endif
32
33 #include <limits.h>
34 #include <stdint.h>
35 #include <stddef.h>
36 #include <assert.h>
37 #include "config.h"
38 #include "attributes.h"
39 #include "dict.h"
40
41 #if ARCH_X86
42 # include "x86/emms.h"
43 #endif
44
45 #ifndef emms_c
46 # define emms_c()
47 #endif
48
49 #ifndef attribute_align_arg
50 #if ARCH_X86_32 && AV_GCC_VERSION_AT_LEAST(4,2)
51 # define attribute_align_arg __attribute__((force_align_arg_pointer))
52 #else
53 # define attribute_align_arg
54 #endif
55 #endif
56
57 #if defined(_MSC_VER) && CONFIG_SHARED
58 # define av_export __declspec(dllimport)
59 #else
60 # define av_export
61 #endif
62
63 #if HAVE_PRAGMA_DEPRECATED
64 # if defined(__ICL)
65 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:1478))
66 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
67 # elif defined(_MSC_VER)
68 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:4996))
69 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
70 # else
71 # define FF_DISABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
72 # define FF_ENABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic warning \"-Wdeprecated-declarations\"")
73 # endif
74 #else
75 # define FF_DISABLE_DEPRECATION_WARNINGS
76 # define FF_ENABLE_DEPRECATION_WARNINGS
77 #endif
78
79 #ifndef INT_BIT
80 # define INT_BIT (CHAR_BIT * sizeof(int))
81 #endif
82
83 // Some broken preprocessors need a second expansion
84 // to be forced to tokenize __VA_ARGS__
85 #define E1(x) x
86
87 /* Check if the hard coded offset of a struct member still matches reality.
88 * Induce a compilation failure if not.
89 */
90 #define AV_CHECK_OFFSET(s, m, o) struct check_##o { \
91 int x_##o[offsetof(s, m) == o? 1: -1]; \
92 }
93
94 #define LOCAL_ALIGNED_A(a, t, v, s, o, ...) \
95 uint8_t la_##v[sizeof(t s o) + (a)]; \
96 t (*v) o = (void *)FFALIGN((uintptr_t)la_##v, a)
97
98 #define LOCAL_ALIGNED_D(a, t, v, s, o, ...) \
99 DECLARE_ALIGNED(a, t, la_##v) s o; \
100 t (*v) o = la_##v
101
102 #define LOCAL_ALIGNED(a, t, v, ...) E1(LOCAL_ALIGNED_A(a, t, v, __VA_ARGS__,,))
103
104 #if HAVE_LOCAL_ALIGNED_8
105 # define LOCAL_ALIGNED_8(t, v, ...) E1(LOCAL_ALIGNED_D(8, t, v, __VA_ARGS__,,))
106 #else
107 # define LOCAL_ALIGNED_8(t, v, ...) LOCAL_ALIGNED(8, t, v, __VA_ARGS__)
108 #endif
109
110 #if HAVE_LOCAL_ALIGNED_16
111 # define LOCAL_ALIGNED_16(t, v, ...) E1(LOCAL_ALIGNED_D(16, t, v, __VA_ARGS__,,))
112 #else
113 # define LOCAL_ALIGNED_16(t, v, ...) LOCAL_ALIGNED(16, t, v, __VA_ARGS__)
114 #endif
115
116 #define FF_ALLOC_OR_GOTO(ctx, p, size, label)\
117 {\
118 p = av_malloc(size);\
119 if (p == NULL && (size) != 0) {\
120 av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
121 goto label;\
122 }\
123 }
124
125 #define FF_ALLOCZ_OR_GOTO(ctx, p, size, label)\
126 {\
127 p = av_mallocz(size);\
128 if (p == NULL && (size) != 0) {\
129 av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
130 goto label;\
131 }\
132 }
133
134 #include "libm.h"
135
136 #if defined(_MSC_VER)
137 #pragma comment(linker, "/include:"EXTERN_PREFIX"avpriv_strtod")
138 #pragma comment(linker, "/include:"EXTERN_PREFIX"avpriv_snprintf")
139 #endif
140
141 /**
142 * Return NULL if CONFIG_SMALL is true, otherwise the argument
143 * without modification. Used to disable the definition of strings
144 * (for example AVCodec long_names).
145 */
146 #if CONFIG_SMALL
147 # define NULL_IF_CONFIG_SMALL(x) NULL
148 #else
149 # define NULL_IF_CONFIG_SMALL(x) x
150 #endif
151
152
153 /**
154 * Define a function with only the non-default version specified.
155 *
156 * On systems with ELF shared libraries, all symbols exported from
157 * Libav libraries are tagged with the name and major version of the
158 * library to which they belong. If a function is moved from one
159 * library to another, a wrapper must be retained in the original
160 * location to preserve binary compatibility.
161 *
162 * Functions defined with this macro will never be used to resolve
163 * symbols by the build-time linker.
164 *
165 * @param type return type of function
166 * @param name name of function
167 * @param args argument list of function
168 * @param ver version tag to assign function
169 */
170 #if HAVE_SYMVER_ASM_LABEL
171 # define FF_SYMVER(type, name, args, ver) \
172 type ff_##name args __asm__ (EXTERN_PREFIX #name "@" ver); \
173 type ff_##name args
174 #elif HAVE_SYMVER_GNU_ASM
175 # define FF_SYMVER(type, name, args, ver) \
176 __asm__ (".symver ff_" #name "," EXTERN_PREFIX #name "@" ver); \
177 type ff_##name args; \
178 type ff_##name args
179 #endif
180
181 /**
182 * Return NULL if a threading library has not been enabled.
183 * Used to disable threading functions in AVCodec definitions
184 * when not needed.
185 */
186 #if HAVE_THREADS
187 # define ONLY_IF_THREADS_ENABLED(x) x
188 #else
189 # define ONLY_IF_THREADS_ENABLED(x) NULL
190 #endif
191
192 /**
193 * Log a generic warning message about a missing feature.
194 *
195 * @param[in] avc a pointer to an arbitrary struct of which the first
196 * field is a pointer to an AVClass struct
197 * @param[in] msg string containing the name of the missing feature
198 */
199 void avpriv_report_missing_feature(void *avc,
200 const char *msg, ...) av_printf_format(2, 3);
201
202 /**
203 * Log a generic warning message about a missing feature.
204 * Additionally request that a sample showcasing the feature be uploaded.
205 *
206 * @param[in] avc a pointer to an arbitrary struct of which the first field is
207 * a pointer to an AVClass struct
208 * @param[in] msg string containing the name of the missing feature
209 */
210 void avpriv_request_sample(void *avc,
211 const char *msg, ...) av_printf_format(2, 3);
212
213 #if HAVE_LIBC_MSVCRT
214 #define avpriv_open ff_open
215 #endif
216
217 /**
218 * A wrapper for open() setting O_CLOEXEC.
219 */
220 int avpriv_open(const char *filename, int flags, ...);
221
222 #endif /* AVUTIL_INTERNAL_H */