internal.h

Go to the documentation of this file.

/*
 * 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

#include <limits.h>
#include <stdint.h>
#include <stddef.h>
#include <assert.h>
#include "config.h"
#include "attributes.h"
#include "timer.h"
#include "cpu.h"
#include "dict.h"
#include "macros.h"
#include "pixfmt.h"
#include "version.h"

#if ARCH_X86
#   include "x86/emms.h"
#endif

#ifndef emms_c
#   define emms_c() while(0)
#endif

#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(_MSC_VER) && CONFIG_SHARED
#    define av_export __declspec(dllimport)
#else
#    define av_export
#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 ignored \"-Wdeprecated-declarations\"")
#        define FF_ENABLE_DEPRECATION_WARNINGS  _Pragma("GCC diagnostic warning \"-Wdeprecated-declarations\"")
#    endif
#else
#    define FF_DISABLE_DEPRECATION_WARNINGS
#    define FF_ENABLE_DEPRECATION_WARNINGS
#endif


#define FF_MEMORY_POISON 0x2a

#define MAKE_ACCESSORS(str, name, type, field) \
    type av_##name##_get_##field(const str *s) { return s->field; } \
    void av_##name##_set_##field(str *s, type v) { s->field = v; }

// Some broken preprocessors need a second expansion
// to be forced to tokenize __VA_ARGS__
#define E1(x) x

/* Check if the hard coded offset of a struct member still matches reality.
 * Induce a compilation failure if not.
 */
#define AV_CHECK_OFFSET(s, m, o) struct check_##o {    \
        int x_##o[offsetof(s, m) == o? 1: -1];         \
    }

#define LOCAL_ALIGNED_A(a, t, v, s, o, ...)             \
    uint8_t la_##v[sizeof(t s o) + (a)];                \
    t (*v) o = (void *)FFALIGN((uintptr_t)la_##v, a)

#define LOCAL_ALIGNED_D(a, t, v, s, o, ...)             \
    DECLARE_ALIGNED(a, t, la_##v) s o;                  \
    t (*v) o = la_##v

#define LOCAL_ALIGNED(a, t, v, ...) E1(LOCAL_ALIGNED_A(a, t, v, __VA_ARGS__,,))

#if HAVE_LOCAL_ALIGNED_8
#   define LOCAL_ALIGNED_8(t, v, ...) E1(LOCAL_ALIGNED_D(8, t, v, __VA_ARGS__,,))
#else
#   define LOCAL_ALIGNED_8(t, v, ...) LOCAL_ALIGNED(8, t, v, __VA_ARGS__)
#endif

#if HAVE_LOCAL_ALIGNED_16
#   define LOCAL_ALIGNED_16(t, v, ...) E1(LOCAL_ALIGNED_D(16, t, v, __VA_ARGS__,,))
#else
#   define LOCAL_ALIGNED_16(t, v, ...) LOCAL_ALIGNED(16, t, v, __VA_ARGS__)
#endif

#if HAVE_LOCAL_ALIGNED_32
#   define LOCAL_ALIGNED_32(t, v, ...) E1(LOCAL_ALIGNED_D(32, t, v, __VA_ARGS__,,))
#else
#   define LOCAL_ALIGNED_32(t, v, ...) LOCAL_ALIGNED(32, t, v, __VA_ARGS__)
#endif

#define FF_ALLOC_OR_GOTO(ctx, p, size, label)\
{\
    p = av_malloc(size);\
    if (!(p) && (size) != 0) {\
        av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
        goto label;\
    }\
}

#define FF_ALLOCZ_OR_GOTO(ctx, p, size, label)\
{\
    p = av_mallocz(size);\
    if (!(p) && (size) != 0) {\
        av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
        goto label;\
    }\
}

#define FF_ALLOC_ARRAY_OR_GOTO(ctx, p, nelem, elsize, label)\
{\
    p = av_malloc_array(nelem, elsize);\
    if (!p) {\
        av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
        goto label;\
    }\
}

#define FF_ALLOCZ_ARRAY_OR_GOTO(ctx, p, nelem, elsize, label)\
{\
    p = av_mallocz_array(nelem, elsize);\
    if (!p) {\
        av_log(ctx, AV_LOG_ERROR, "Cannot allocate memory.\n");\
        goto label;\
    }\
}

#include "libm.h"

/**
 * Return NULL if CONFIG_SMALL is true, otherwise the argument
 * without modification. Used to disable the definition of strings
 * (for example AVCodec long_names).
 */
#if CONFIG_SMALL
#   define NULL_IF_CONFIG_SMALL(x) NULL
#else
#   define NULL_IF_CONFIG_SMALL(x) x
#endif

/**
 * Define a function with only the non-default version specified.
 *
 * On systems with ELF shared libraries, all symbols exported from
 * FFmpeg libraries are tagged with the name and major version of the
 * library to which they belong.  If a function is moved from one
 * library to another, a wrapper must be retained in the original
 * location to preserve binary compatibility.
 *
 * Functions defined with this macro will never be used to resolve
 * symbols by the build-time linker.
 *
 * @param type return type of function
 * @param name name of function
 * @param args argument list of function
 * @param ver  version tag to assign function
 */
#if HAVE_SYMVER_ASM_LABEL
#   define FF_SYMVER(type, name, args, ver)                     \
    type ff_##name args __asm__ (EXTERN_PREFIX #name "@" ver);  \
    type ff_##name args
#elif HAVE_SYMVER_GNU_ASM
#   define FF_SYMVER(type, name, args, ver)                             \
    __asm__ (".symver ff_" #name "," EXTERN_PREFIX #name "@" ver);      \
    type ff_##name args;                                                \
    type ff_##name args
#endif

/**
 * Return NULL if a threading library has not been enabled.
 * Used to disable threading functions in AVCodec definitions
 * when not needed.
 */
#if HAVE_THREADS
#   define ONLY_IF_THREADS_ENABLED(x) x
#else
#   define ONLY_IF_THREADS_ENABLED(x) NULL
#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 avpriv_open ff_open
#define PTRDIFF_SPECIFIER "Id"
#define SIZE_SPECIFIER "Iu"
#else
#define PTRDIFF_SPECIFIER "td"
#define SIZE_SPECIFIER "zu"
#endif

#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

/**
 * Clip and convert a double value into the long long amin-amax range.
 * This function is needed because conversion of floating point to integers when
 * it does not fit in the integer's representation does not necessarily saturate
 * correctly (usually converted to a cvttsd2si on x86) which saturates numbers
 * > INT64_MAX to INT64_MIN. The standard marks such conversions as undefined
 * behavior, allowing this sort of mathematically bogus conversions. This provides
 * a safe alternative that is slower obviously but assures safety and better
 * mathematical behavior.
 * @param a value to clip
 * @param amin minimum value of the clip range
 * @param amax maximum value of the clip range
 * @return clipped value
 */
static av_always_inline av_const int64_t ff_rint64_clip(double a, int64_t amin, int64_t amax)
{
    int64_t res;
#if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
    if (amin > amax) abort();
#endif
    // INT64_MAX+1,INT64_MIN are exactly representable as IEEE doubles
    // do range checks first
    if (a >=  9223372036854775808.0)
        return amax;
    if (a <= -9223372036854775808.0)
        return amin;

    // safe to call llrint and clip accordingly
    res = llrint(a);
    if (res > amax)
        return amax;
    if (res < amin)
        return amin;
    return res;
}

/**
 * Compute 10^x for floating point values. Note: this function is by no means
 * "correctly rounded", and is meant as a fast, reasonably accurate approximation.
 * For instance, maximum relative error for the double precision variant is
 * ~ 1e-13 for very small and very large values.
 * This is ~2x faster than GNU libm's approach, which is still off by 2ulp on
 * some inputs.
 * @param x exponent
 * @return 10^x
 */
static av_always_inline double ff_exp10(double x)
{
    return exp2(M_LOG2_10 * x);
}

static av_always_inline float ff_exp10f(float x)
{
    return exp2f(M_LOG2_10 * x);
}

/**
 * A wrapper for open() setting O_CLOEXEC.
 */
av_warn_unused_result
int avpriv_open(const char *filename, int flags, ...);

int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt);

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;
}

void ff_check_pixfmt_descriptors(void);

extern const uint8_t ff_reverse[256];

#endif /* AVUTIL_INTERNAL_H */