FFmpeg
internal.h
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1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 // This can be enabled to allow detection of additional integer overflows with ubsan
34 //#define CHECKED
35 
36 #include <limits.h>
37 #include <stdint.h>
38 #include <stddef.h>
39 #include <assert.h>
40 #include "config.h"
41 #include "attributes.h"
42 #include "timer.h"
43 #include "cpu.h"
44 #include "dict.h"
45 #include "macros.h"
46 #include "pixfmt.h"
47 #include "version.h"
48 
49 #if ARCH_X86
50 # include "x86/emms.h"
51 #endif
52 
53 #ifndef emms_c
54 # define emms_c() do {} while(0)
55 #endif
56 
57 #ifndef attribute_align_arg
58 #if ARCH_X86_32 && AV_GCC_VERSION_AT_LEAST(4,2)
59 # define attribute_align_arg __attribute__((force_align_arg_pointer))
60 #else
61 # define attribute_align_arg
62 #endif
63 #endif
64 
65 #if defined(_WIN32) && CONFIG_SHARED && !defined(BUILDING_avutil)
66 # define av_export_avutil __declspec(dllimport)
67 #else
68 # define av_export_avutil
69 #endif
70 
71 #if HAVE_PRAGMA_DEPRECATED
72 # if defined(__ICL) || defined (__INTEL_COMPILER)
73 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:1478))
74 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
75 # elif defined(_MSC_VER)
76 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:4996))
77 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
78 # else
79 # define FF_DISABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
80 # define FF_ENABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic pop")
81 # endif
82 #else
83 # define FF_DISABLE_DEPRECATION_WARNINGS
84 # define FF_ENABLE_DEPRECATION_WARNINGS
85 #endif
86 
87 
88 #define FF_MEMORY_POISON 0x2a
89 
90 #define MAKE_ACCESSORS(str, name, type, field) \
91  type av_##name##_get_##field(const str *s) { return s->field; } \
92  void av_##name##_set_##field(str *s, type v) { s->field = v; }
93 
94 /* Check if the hard coded offset of a struct member still matches reality.
95  * Induce a compilation failure if not.
96  */
97 #define AV_CHECK_OFFSET(s, m, o) struct check_##o { \
98  int x_##o[offsetof(s, m) == o? 1: -1]; \
99  }
100 
101 
102 #define FF_ALLOC_TYPED_ARRAY(p, nelem) (p = av_malloc_array(nelem, sizeof(*p)))
103 #define FF_ALLOCZ_TYPED_ARRAY(p, nelem) (p = av_mallocz_array(nelem, sizeof(*p)))
104 
105 #include "libm.h"
106 
107 /**
108  * Return NULL if CONFIG_SMALL is true, otherwise the argument
109  * without modification. Used to disable the definition of strings
110  * (for example AVCodec long_names).
111  */
112 #if CONFIG_SMALL
113 # define NULL_IF_CONFIG_SMALL(x) NULL
114 #else
115 # define NULL_IF_CONFIG_SMALL(x) x
116 #endif
117 
118 /**
119  * Define a function with only the non-default version specified.
120  *
121  * On systems with ELF shared libraries, all symbols exported from
122  * FFmpeg libraries are tagged with the name and major version of the
123  * library to which they belong. If a function is moved from one
124  * library to another, a wrapper must be retained in the original
125  * location to preserve binary compatibility.
126  *
127  * Functions defined with this macro will never be used to resolve
128  * symbols by the build-time linker.
129  *
130  * @param type return type of function
131  * @param name name of function
132  * @param args argument list of function
133  * @param ver version tag to assign function
134  */
135 #if HAVE_SYMVER_ASM_LABEL
136 # define FF_SYMVER(type, name, args, ver) \
137  type ff_##name args __asm__ (EXTERN_PREFIX #name "@" ver); \
138  type ff_##name args
139 #elif HAVE_SYMVER_GNU_ASM
140 # define FF_SYMVER(type, name, args, ver) \
141  __asm__ (".symver ff_" #name "," EXTERN_PREFIX #name "@" ver); \
142  type ff_##name args; \
143  type ff_##name args
144 #endif
145 
146 /**
147  * Return NULL if a threading library has not been enabled.
148  * Used to disable threading functions in AVCodec definitions
149  * when not needed.
150  */
151 #if HAVE_THREADS
152 # define ONLY_IF_THREADS_ENABLED(x) x
153 #else
154 # define ONLY_IF_THREADS_ENABLED(x) NULL
155 #endif
156 
157 /**
158  * Log a generic warning message about a missing feature.
159  *
160  * @param[in] avc a pointer to an arbitrary struct of which the first
161  * field is a pointer to an AVClass struct
162  * @param[in] msg string containing the name of the missing feature
163  */
164 void avpriv_report_missing_feature(void *avc,
165  const char *msg, ...) av_printf_format(2, 3);
166 
167 /**
168  * Log a generic warning message about a missing feature.
169  * Additionally request that a sample showcasing the feature be uploaded.
170  *
171  * @param[in] avc a pointer to an arbitrary struct of which the first field is
172  * a pointer to an AVClass struct
173  * @param[in] msg string containing the name of the missing feature
174  */
175 void avpriv_request_sample(void *avc,
176  const char *msg, ...) av_printf_format(2, 3);
177 
178 #if HAVE_LIBC_MSVCRT
179 #include <crtversion.h>
180 #if defined(_VC_CRT_MAJOR_VERSION) && _VC_CRT_MAJOR_VERSION < 14
181 #pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_strtod")
182 #pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_snprintf")
183 #endif
184 
185 #define avpriv_open ff_open
186 #define avpriv_tempfile ff_tempfile
187 #define PTRDIFF_SPECIFIER "Id"
188 #define SIZE_SPECIFIER "Iu"
189 #else
190 #define PTRDIFF_SPECIFIER "td"
191 #define SIZE_SPECIFIER "zu"
192 #endif
193 
194 #ifdef DEBUG
195 # define ff_dlog(ctx, ...) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__)
196 #else
197 # define ff_dlog(ctx, ...) do { if (0) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__); } while (0)
198 #endif
199 
200 // For debuging we use signed operations so overflows can be detected (by ubsan)
201 // For production we use unsigned so there are no undefined operations
202 #ifdef CHECKED
203 #define SUINT int
204 #define SUINT32 int32_t
205 #else
206 #define SUINT unsigned
207 #define SUINT32 uint32_t
208 #endif
209 
210 /**
211  * Clip and convert a double value into the long long amin-amax range.
212  * This function is needed because conversion of floating point to integers when
213  * it does not fit in the integer's representation does not necessarily saturate
214  * correctly (usually converted to a cvttsd2si on x86) which saturates numbers
215  * > INT64_MAX to INT64_MIN. The standard marks such conversions as undefined
216  * behavior, allowing this sort of mathematically bogus conversions. This provides
217  * a safe alternative that is slower obviously but assures safety and better
218  * mathematical behavior.
219  * @param a value to clip
220  * @param amin minimum value of the clip range
221  * @param amax maximum value of the clip range
222  * @return clipped value
223  */
224 static av_always_inline av_const int64_t ff_rint64_clip(double a, int64_t amin, int64_t amax)
225 {
226  int64_t res;
227 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
228  if (amin > amax) abort();
229 #endif
230  // INT64_MAX+1,INT64_MIN are exactly representable as IEEE doubles
231  // do range checks first
232  if (a >= 9223372036854775808.0)
233  return amax;
234  if (a <= -9223372036854775808.0)
235  return amin;
236 
237  // safe to call llrint and clip accordingly
238  res = llrint(a);
239  if (res > amax)
240  return amax;
241  if (res < amin)
242  return amin;
243  return res;
244 }
245 
246 /**
247  * A wrapper for open() setting O_CLOEXEC.
248  */
250 int avpriv_open(const char *filename, int flags, ...);
251 
252 /**
253  * Wrapper to work around the lack of mkstemp() on mingw.
254  * Also, tries to create file in /tmp first, if possible.
255  * *prefix can be a character constant; *filename will be allocated internally.
256  * @return file descriptor of opened file (or negative value corresponding to an
257  * AVERROR code on error)
258  * and opened file name in **filename.
259  * @note On very old libcs it is necessary to set a secure umask before
260  * calling this, av_tempfile() can't call umask itself as it is used in
261  * libraries and could interfere with the calling application.
262  */
263 int avpriv_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx);
264 
265 int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt);
266 
267 static av_always_inline av_const int avpriv_mirror(int x, int w)
268 {
269  if (!w)
270  return 0;
271 
272  while ((unsigned)x > (unsigned)w) {
273  x = -x;
274  if (x < 0)
275  x += 2 * w;
276  }
277  return x;
278 }
279 
280 void ff_check_pixfmt_descriptors(void);
281 
282 /**
283  * Set a dictionary value to an ISO-8601 compliant timestamp string.
284  *
285  * @param dict pointer to a pointer to a dictionary struct. If *dict is NULL
286  * a dictionary struct is allocated and put in *dict.
287  * @param key metadata key
288  * @param timestamp unix timestamp in microseconds
289  * @return <0 on error
290  */
291 int avpriv_dict_set_timestamp(AVDictionary **dict, const char *key, int64_t timestamp);
292 
293 // Helper macro for AV_PIX_FMT_FLAG_PSEUDOPAL deprecation. Code inside FFmpeg
294 // should always use FF_PSEUDOPAL. Once the public API flag gets removed, all
295 // code using it is dead code.
296 #if FF_API_PSEUDOPAL
297 #define FF_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
298 #else
299 #define FF_PSEUDOPAL 0
300 #endif
301 
302 #endif /* AVUTIL_INTERNAL_H */
#define av_const
Definition: attributes.h:82
av_warn_unused_result int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
static enum AVPixelFormat pix_fmt
static av_always_inline av_const int64_t ff_rint64_clip(double a, int64_t amin, int64_t amax)
Clip and convert a double value into the long long amin-amax range.
Definition: internal.h:224
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
const char * key
Macro definitions for various function/variable attributes.
Public dictionary API.
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
high precision timer, useful to profile code
Utility Preprocessor macros.
int avpriv_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx)
Wrapper to work around the lack of mkstemp() on mingw.
Definition: file_open.c:110
Libavutil version macros.
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:161
uint8_t w
Definition: llviddspenc.c:39
int avpriv_dict_set_timestamp(AVDictionary **dict, const char *key, int64_t timestamp)
Set a dictionary value to an ISO-8601 compliant timestamp string.
Definition: dict.c:258
static av_always_inline av_const int avpriv_mirror(int x, int w)
Definition: internal.h:267
#define llrint(x)
Definition: libm.h:394
Replacements for frequently missing libm functions.
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
#define flags(name, subs,...)
Definition: cbs_av1.c:561
#define av_warn_unused_result
Definition: attributes.h:62
void ff_check_pixfmt_descriptors(void)
Definition: pixdesc.c:2628
pixel format definitions
int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
Definition: imgutils.c:176
#define av_always_inline
Definition: attributes.h:45
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64