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 "dict.h"
44 #include "macros.h"
45 #include "pixfmt.h"
46 #include "version.h"
47 
48 #if ARCH_X86
49 # include "x86/emms.h"
50 #endif
51 
52 #ifndef emms_c
53 # define emms_c() do {} while(0)
54 #endif
55 
56 #ifndef attribute_align_arg
57 #if ARCH_X86_32 && AV_GCC_VERSION_AT_LEAST(4,2)
58 # define attribute_align_arg __attribute__((force_align_arg_pointer))
59 #else
60 # define attribute_align_arg
61 #endif
62 #endif
63 
64 #if defined(_WIN32) && CONFIG_SHARED && !defined(BUILDING_avutil)
65 # define av_export_avutil __declspec(dllimport)
66 #else
67 # define av_export_avutil
68 #endif
69 
70 #if HAVE_PRAGMA_DEPRECATED
71 # if defined(__ICL) || defined (__INTEL_COMPILER)
72 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:1478))
73 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
74 # elif defined(_MSC_VER)
75 # define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:4996))
76 # define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
77 # else
78 # define FF_DISABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
79 # define FF_ENABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic pop")
80 # endif
81 #else
82 # define FF_DISABLE_DEPRECATION_WARNINGS
83 # define FF_ENABLE_DEPRECATION_WARNINGS
84 #endif
85 
86 
87 #define FF_MEMORY_POISON 0x2a
88 
89 /* Check if the hard coded offset of a struct member still matches reality.
90  * Induce a compilation failure if not.
91  */
92 #define AV_CHECK_OFFSET(s, m, o) struct check_##o { \
93  int x_##o[offsetof(s, m) == o? 1: -1]; \
94  }
95 
96 
97 #define FF_ALLOC_TYPED_ARRAY(p, nelem) (p = av_malloc_array(nelem, sizeof(*p)))
98 #define FF_ALLOCZ_TYPED_ARRAY(p, nelem) (p = av_calloc(nelem, sizeof(*p)))
99 
100 #define FF_PTR_ADD(ptr, off) ((off) ? (ptr) + (off) : (ptr))
101 
102 /**
103  * Access a field in a structure by its offset.
104  */
105 #define FF_FIELD_AT(type, off, obj) (*(type *)((char *)&(obj) + (off)))
106 
107 #include "libm.h"
108 
109 /**
110  * Return NULL if CONFIG_SMALL is true, otherwise the argument
111  * without modification. Used to disable the definition of strings
112  * (for example AVCodec long_names).
113  */
114 #if CONFIG_SMALL
115 # define NULL_IF_CONFIG_SMALL(x) NULL
116 #else
117 # define NULL_IF_CONFIG_SMALL(x) x
118 #endif
119 
120 /**
121  * Define a function with only the non-default version specified.
122  *
123  * On systems with ELF shared libraries, all symbols exported from
124  * FFmpeg libraries are tagged with the name and major version of the
125  * library to which they belong. If a function is moved from one
126  * library to another, a wrapper must be retained in the original
127  * location to preserve binary compatibility.
128  *
129  * Functions defined with this macro will never be used to resolve
130  * symbols by the build-time linker.
131  *
132  * @param type return type of function
133  * @param name name of function
134  * @param args argument list of function
135  * @param ver version tag to assign function
136  */
137 #if HAVE_SYMVER_ASM_LABEL
138 # define FF_SYMVER(type, name, args, ver) \
139  type ff_##name args __asm__ (EXTERN_PREFIX #name "@" ver); \
140  type ff_##name args
141 #elif HAVE_SYMVER_GNU_ASM
142 # define FF_SYMVER(type, name, args, ver) \
143  __asm__ (".symver ff_" #name "," EXTERN_PREFIX #name "@" ver); \
144  type ff_##name args; \
145  type ff_##name args
146 #endif
147 
148 /**
149  * Return NULL if a threading library has not been enabled.
150  * Used to disable threading functions in AVCodec definitions
151  * when not needed.
152  */
153 #if HAVE_THREADS
154 # define ONLY_IF_THREADS_ENABLED(x) x
155 #else
156 # define ONLY_IF_THREADS_ENABLED(x) NULL
157 #endif
158 
159 /**
160  * Log a generic warning message about a missing feature.
161  *
162  * @param[in] avc a pointer to an arbitrary struct of which the first
163  * field is a pointer to an AVClass struct
164  * @param[in] msg string containing the name of the missing feature
165  */
166 void avpriv_report_missing_feature(void *avc,
167  const char *msg, ...) av_printf_format(2, 3);
168 
169 /**
170  * Log a generic warning message about a missing feature.
171  * Additionally request that a sample showcasing the feature be uploaded.
172  *
173  * @param[in] avc a pointer to an arbitrary struct of which the first field is
174  * a pointer to an AVClass struct
175  * @param[in] msg string containing the name of the missing feature
176  */
177 void avpriv_request_sample(void *avc,
178  const char *msg, ...) av_printf_format(2, 3);
179 
180 #if HAVE_LIBC_MSVCRT
181 #include <crtversion.h>
182 #if defined(_VC_CRT_MAJOR_VERSION) && _VC_CRT_MAJOR_VERSION < 14
183 #pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_strtod")
184 #pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_snprintf")
185 #endif
186 
187 #define avpriv_open ff_open
188 #define avpriv_tempfile ff_tempfile
189 #define PTRDIFF_SPECIFIER "Id"
190 #define SIZE_SPECIFIER "Iu"
191 #else
192 #define PTRDIFF_SPECIFIER "td"
193 #define SIZE_SPECIFIER "zu"
194 #endif
195 
196 #ifdef DEBUG
197 # define ff_dlog(ctx, ...) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__)
198 #else
199 # define ff_dlog(ctx, ...) do { if (0) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__); } while (0)
200 #endif
201 
202 #ifdef TRACE
203 # define ff_tlog(ctx, ...) av_log(ctx, AV_LOG_TRACE, __VA_ARGS__)
204 #else
205 # define ff_tlog(ctx, ...) do { } while(0)
206 #endif
207 
208 // For debuging we use signed operations so overflows can be detected (by ubsan)
209 // For production we use unsigned so there are no undefined operations
210 #ifdef CHECKED
211 #define SUINT int
212 #define SUINT32 int32_t
213 #else
214 #define SUINT unsigned
215 #define SUINT32 uint32_t
216 #endif
217 
218 /**
219  * Clip and convert a double value into the long long amin-amax range.
220  * This function is needed because conversion of floating point to integers when
221  * it does not fit in the integer's representation does not necessarily saturate
222  * correctly (usually converted to a cvttsd2si on x86) which saturates numbers
223  * > INT64_MAX to INT64_MIN. The standard marks such conversions as undefined
224  * behavior, allowing this sort of mathematically bogus conversions. This provides
225  * a safe alternative that is slower obviously but assures safety and better
226  * mathematical behavior.
227  * @param a value to clip
228  * @param amin minimum value of the clip range
229  * @param amax maximum value of the clip range
230  * @return clipped value
231  */
232 static av_always_inline av_const int64_t ff_rint64_clip(double a, int64_t amin, int64_t amax)
233 {
234  int64_t res;
235 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
236  if (amin > amax) abort();
237 #endif
238  // INT64_MAX+1,INT64_MIN are exactly representable as IEEE doubles
239  // do range checks first
240  if (a >= 9223372036854775808.0)
241  return amax;
242  if (a <= -9223372036854775808.0)
243  return amin;
244 
245  // safe to call llrint and clip accordingly
246  res = llrint(a);
247  if (res > amax)
248  return amax;
249  if (res < amin)
250  return amin;
251  return res;
252 }
253 
254 /**
255  * A wrapper for open() setting O_CLOEXEC.
256  */
258 int avpriv_open(const char *filename, int flags, ...);
259 
260 /**
261  * Wrapper to work around the lack of mkstemp() on mingw.
262  * Also, tries to create file in /tmp first, if possible.
263  * *prefix can be a character constant; *filename will be allocated internally.
264  * @return file descriptor of opened file (or negative value corresponding to an
265  * AVERROR code on error)
266  * and opened file name in **filename.
267  * @note On very old libcs it is necessary to set a secure umask before
268  * calling this, av_tempfile() can't call umask itself as it is used in
269  * libraries and could interfere with the calling application.
270  */
271 int avpriv_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx);
272 
273 int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt);
274 
275 static av_always_inline av_const int avpriv_mirror(int x, int w)
276 {
277  if (!w)
278  return 0;
279 
280  while ((unsigned)x > (unsigned)w) {
281  x = -x;
282  if (x < 0)
283  x += 2 * w;
284  }
285  return x;
286 }
287 
288 void ff_check_pixfmt_descriptors(void);
289 
290 /**
291  * Set a dictionary value to an ISO-8601 compliant timestamp string.
292  *
293  * @param dict pointer to a pointer to a dictionary struct. If *dict is NULL
294  * a dictionary struct is allocated and put in *dict.
295  * @param key metadata key
296  * @param timestamp unix timestamp in microseconds
297  * @return <0 on error
298  */
299 int avpriv_dict_set_timestamp(AVDictionary **dict, const char *key, int64_t timestamp);
300 
301 #endif /* AVUTIL_INTERNAL_H */
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
libm.h
avpriv_set_systematic_pal2
int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
Definition: imgutils.c:178
w
uint8_t w
Definition: llviddspenc.c:38
av_const
#define av_const
Definition: attributes.h:84
AVDictionary
Definition: dict.c:30
macros.h
avpriv_tempfile
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
limits.h
pix_fmt
static enum AVPixelFormat pix_fmt
Definition: demuxing_decoding.c:41
avpriv_request_sample
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
key
const char * key
Definition: hwcontext_opencl.c:168
av_printf_format
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:161
timer.h
avpriv_mirror
static av_always_inline av_const int avpriv_mirror(int x, int w)
Definition: internal.h:275
avpriv_report_missing_feature
void avpriv_report_missing_feature(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
a
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:41
avpriv_dict_set_timestamp
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
attributes.h
ff_check_pixfmt_descriptors
void ff_check_pixfmt_descriptors(void)
Definition: pixdesc.c:2619
av_warn_unused_result
#define av_warn_unused_result
Definition: attributes.h:64
emms.h
av_always_inline
#define av_always_inline
Definition: attributes.h:49
version.h
pixfmt.h
dict.h
llrint
#define llrint(x)
Definition: libm.h:394
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
ff_rint64_clip
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:232
avpriv_open
av_warn_unused_result int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66