text: /*
   * 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);
  }
  
  /**
   * Compute x^y for floating point x, y. Note: this function is faster than the
   * libm variant due to mainly 2 reasons:
   * 1. It does not handle any edge cases. In particular, this is only guaranteed
   * to work correctly for x > 0.
   * 2. It is not as accurate as a standard nearly "correctly rounded" libm variant.
   * @param x base
   * @param y exponent
   * @return x^y
   */
  static av_always_inline float ff_fast_powf(float x, float y)
  {
      return expf(logf(x) * y);
  }
  
  
  /**
   * 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 */
  