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FFmpeg/libavutil/internal.h

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/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* common internal API header
*/
#ifndef AVUTIL_INTERNAL_H
#define AVUTIL_INTERNAL_H
#if !defined(DEBUG) && !defined(NDEBUG)
# define NDEBUG
#endif
// This can be enabled to allow detection of additional integer overflows with ubsan
//#define CHECKED
#include <limits.h>
#include <stdint.h>
#include <stddef.h>
#include <assert.h>
#include <stdio.h>
#include "config.h"
#include "attributes.h"
#include "libm.h"
#include "macros.h"
#ifndef attribute_align_arg
#if ARCH_X86_32 && AV_GCC_VERSION_AT_LEAST(4,2)
# define attribute_align_arg __attribute__((force_align_arg_pointer))
#else
# define attribute_align_arg
#endif
#endif
#if defined(_WIN32) && CONFIG_SHARED && !defined(BUILDING_avutil)
# define av_export_avutil __declspec(dllimport)
#else
# define av_export_avutil
Add support for building shared libraries with MSVC This requires the makedef perl script by Derek, from the c89-to-c99 repo. That scripts produces a .def file, listing the symbols to be exported, based on the gcc version scripts and the built object files. To properly load non-function symbols from DLL files, the data symbol declarations need to have the attribute __declspec(dllimport) when building the calling code. (On mingw, the linker can fix this up automatically, which is why it has not been an issue so far. If this attribute is omitted, linking actually succeeds, but reads from the table will not produce the desired results at runtime.) MSVC seems to manage to link DLLs (and run properly) even if this attribute is present while building the library itself (which normally isn't recommended) - other object files in the same library manage to link to the symbol (with a small warning at link time, like "warning LNK4049: locally defined symbol _avpriv_mpa_bitrate_tab imported" - it doesn't seem to be possible to squelch this warning), and the definition of the tables themselves produce a warning that can be squelched ("warning C4273: 'avpriv_mpa_bitrate_tab' : inconsistent dll linkage, see previous definition of 'avpriv_mpa_bitrate_tab'). In this setup, mingw isn't able to link object files that refer to data symbols with __declspec(dllimport) without those symbols actually being linked via a DLL (linking avcodec.dll ends up with errors like "undefined reference to `__imp__avpriv_mpa_freq_tab'"). The dllimport declspec isn't needed at all in mingw, so we simply choose not to declare it for other compilers than MSVC that requires it. (If ICL support later requires it, the condition can be extended later to include both of them.) This also implies that code that is built to link to a certain library as a DLL can't link to the same library as a static library. Therefore, we only allow building either static or shared but not both at the same time. (That is, static libraries as such can be, and actually are, built - this is used for linking the test tools to internal symbols in the libraries - but e.g. libavformat built to link to libavcodec as a DLL cannot link statically to libavcodec.) Also, linking to DLLs is slightly different from linking to shared libraries on other platforms. DLLs use a thing called import libraries, which is basically a stub library allowing the linker to know which symbols exist in the DLL and what name the DLL will have at runtime. In mingw/gcc, the import library is usually named libfoo.dll.a, which goes next to a static library named libfoo.a. This allows gcc to pick the dynamic one, if available, from the normal -lfoo switches, just as it does for libfoo.a vs libfoo.so on Unix. On MSVC however, you need to literally specify the name of the import library instead of the static library. Signed-off-by: Martin Storsjö <martin@martin.st>
2012-10-18 11:53:19 +03:00
#endif
#if HAVE_PRAGMA_DEPRECATED
# if defined(__ICL) || defined (__INTEL_COMPILER)
# define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:1478))
# define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
# elif defined(_MSC_VER)
# define FF_DISABLE_DEPRECATION_WARNINGS __pragma(warning(push)) __pragma(warning(disable:4996))
# define FF_ENABLE_DEPRECATION_WARNINGS __pragma(warning(pop))
# else
# define FF_DISABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic push") _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
# define FF_ENABLE_DEPRECATION_WARNINGS _Pragma("GCC diagnostic pop")
# endif
#else
# define FF_DISABLE_DEPRECATION_WARNINGS
# define FF_ENABLE_DEPRECATION_WARNINGS
#endif
#define FF_ALLOC_TYPED_ARRAY(p, nelem) (p = av_malloc_array(nelem, sizeof(*p)))
#define FF_ALLOCZ_TYPED_ARRAY(p, nelem) (p = av_calloc(nelem, sizeof(*p)))
#define FF_PTR_ADD(ptr, off) ((off) ? (ptr) + (off) : (ptr))
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/**
* Access a field in a structure by its offset.
*/
#define FF_FIELD_AT(type, off, obj) (*(type *)((char *)&(obj) + (off)))
/**
* Return NULL if CONFIG_SMALL is true, otherwise the argument
* without modification. Used to disable the definition of strings.
*/
#if CONFIG_SMALL
# define NULL_IF_CONFIG_SMALL(x) NULL
#else
# define NULL_IF_CONFIG_SMALL(x) x
#endif
/**
* Log a generic warning message about a missing feature.
*
* @param[in] avc a pointer to an arbitrary struct of which the first
* field is a pointer to an AVClass struct
* @param[in] msg string containing the name of the missing feature
*/
void avpriv_report_missing_feature(void *avc,
const char *msg, ...) av_printf_format(2, 3);
/**
* Log a generic warning message about a missing feature.
* Additionally request that a sample showcasing the feature be uploaded.
*
* @param[in] avc a pointer to an arbitrary struct of which the first field is
* a pointer to an AVClass struct
* @param[in] msg string containing the name of the missing feature
*/
void avpriv_request_sample(void *avc,
const char *msg, ...) av_printf_format(2, 3);
#if HAVE_LIBC_MSVCRT
#include <crtversion.h>
#if defined(_VC_CRT_MAJOR_VERSION) && _VC_CRT_MAJOR_VERSION < 14
#pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_strtod")
#pragma comment(linker, "/include:" EXTERN_PREFIX "avpriv_snprintf")
#endif
#define PTRDIFF_SPECIFIER "Id"
#define SIZE_SPECIFIER "Iu"
#else
#define PTRDIFF_SPECIFIER "td"
#define SIZE_SPECIFIER "zu"
#endif
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#ifdef DEBUG
# define ff_dlog(ctx, ...) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__)
#else
# define ff_dlog(ctx, ...) do { if (0) av_log(ctx, AV_LOG_DEBUG, __VA_ARGS__); } while (0)
#endif
#ifdef TRACE
# define ff_tlog(ctx, ...) av_log(ctx, AV_LOG_TRACE, __VA_ARGS__)
#else
# define ff_tlog(ctx, ...) do { } while(0)
#endif
// For debuging we use signed operations so overflows can be detected (by ubsan)
// For production we use unsigned so there are no undefined operations
#ifdef CHECKED
#define SUINT int
#define SUINT32 int32_t
#else
#define SUINT unsigned
#define SUINT32 uint32_t
#endif
static av_always_inline av_const int avpriv_mirror(int x, int w)
{
if (!w)
return 0;
while ((unsigned)x > (unsigned)w) {
x = -x;
if (x < 0)
x += 2 * w;
}
return x;
}
#endif /* AVUTIL_INTERNAL_H */