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#ifndef OPENCV_CORE_SATURATE_HPP
#define OPENCV_CORE_SATURATE_HPP

#include "opencv2/core/cvdef.h"
#include "opencv2/core/fast_math.hpp"
#include <climits>

namespace cv {

//! @addtogroup core_utils
//! @{

/////////////// saturate_cast (used in image & signal processing)
//////////////////////

/** @brief Template function for accurate conversion from one primitive type to
 another.

 The function saturate_cast resembles the standard C++ cast operations, such as
 static_cast\<T\>() and others. It perform an efficient and accurate conversion
 from one primitive type to another (see the introduction chapter). saturate in
 the name means that when the input value v is out of the range of the target
 type, the result is not formed just by taking low bits of the input, but
 instead the value is clipped. For example:
 @code
 uchar a = saturate_cast<uchar>(-100); // a = 0 (UCHAR_MIN)
 short b = saturate_cast<short>(33333.33333); // b = 32767 (SHRT_MAX)
 @endcode
 Such clipping is done when the target type is unsigned char , signed char ,
 unsigned short or signed short . For 32-bit integers, no clipping is done.

 When the parameter is a floating-point value and the target type is an integer
 (8-, 16- or 32-bit), the floating-point value is first rounded to the nearest
 integer and then clipped if needed (when the target type is 8- or 16-bit).

 @param v Function parameter.
 @sa add, subtract, multiply, divide, Mat::convertTo
 */
template <typename _Tp> static inline _Tp saturate_cast(uchar v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(schar v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(ushort v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(short v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(unsigned v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(int v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(float v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(double v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(int64 v) {
  return _Tp(v);
}
/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(uint64 v) {
  return _Tp(v);
}

template <> inline uchar saturate_cast<uchar>(schar v) {
  return (uchar)std::max((int)v, 0);
}
template <> inline uchar saturate_cast<uchar>(ushort v) {
  return (uchar)std::min((unsigned)v, (unsigned)UCHAR_MAX);
}
template <> inline uchar saturate_cast<uchar>(int v) {
  return (uchar)((unsigned)v <= UCHAR_MAX ? v : v > 0 ? UCHAR_MAX : 0);
}
template <> inline uchar saturate_cast<uchar>(short v) {
  return saturate_cast<uchar>((int)v);
}
template <> inline uchar saturate_cast<uchar>(unsigned v) {
  return (uchar)std::min(v, (unsigned)UCHAR_MAX);
}
template <> inline uchar saturate_cast<uchar>(float v) {
  int iv = cvRound(v);
  return saturate_cast<uchar>(iv);
}
template <> inline uchar saturate_cast<uchar>(double v) {
  int iv = cvRound(v);
  return saturate_cast<uchar>(iv);
}
template <> inline uchar saturate_cast<uchar>(int64 v) {
  return (uchar)((uint64)v <= (uint64)UCHAR_MAX ? v : v > 0 ? UCHAR_MAX : 0);
}
template <> inline uchar saturate_cast<uchar>(uint64 v) {
  return (uchar)std::min(v, (uint64)UCHAR_MAX);
}

template <> inline schar saturate_cast<schar>(uchar v) {
  return (schar)std::min((int)v, SCHAR_MAX);
}
template <> inline schar saturate_cast<schar>(ushort v) {
  return (schar)std::min((unsigned)v, (unsigned)SCHAR_MAX);
}
template <> inline schar saturate_cast<schar>(int v) {
  return (schar)((unsigned)(v - SCHAR_MIN) <= (unsigned)UCHAR_MAX ? v
                 : v > 0                                          ? SCHAR_MAX
                                                                  : SCHAR_MIN);
}
template <> inline schar saturate_cast<schar>(short v) {
  return saturate_cast<schar>((int)v);
}
template <> inline schar saturate_cast<schar>(unsigned v) {
  return (schar)std::min(v, (unsigned)SCHAR_MAX);
}
template <> inline schar saturate_cast<schar>(float v) {
  int iv = cvRound(v);
  return saturate_cast<schar>(iv);
}
template <> inline schar saturate_cast<schar>(double v) {
  int iv = cvRound(v);
  return saturate_cast<schar>(iv);
}
template <> inline schar saturate_cast<schar>(int64 v) {
  return (schar)((uint64)((int64)v - SCHAR_MIN) <= (uint64)UCHAR_MAX ? v
                 : v > 0                                             ? SCHAR_MAX
                         : SCHAR_MIN);
}
template <> inline schar saturate_cast<schar>(uint64 v) {
  return (schar)std::min(v, (uint64)SCHAR_MAX);
}

template <> inline ushort saturate_cast<ushort>(schar v) {
  return (ushort)std::max((int)v, 0);
}
template <> inline ushort saturate_cast<ushort>(short v) {
  return (ushort)std::max((int)v, 0);
}
template <> inline ushort saturate_cast<ushort>(int v) {
  return (ushort)((unsigned)v <= (unsigned)USHRT_MAX ? v
                  : v > 0                            ? USHRT_MAX
                                                     : 0);
}
template <> inline ushort saturate_cast<ushort>(unsigned v) {
  return (ushort)std::min(v, (unsigned)USHRT_MAX);
}
template <> inline ushort saturate_cast<ushort>(float v) {
  int iv = cvRound(v);
  return saturate_cast<ushort>(iv);
}
template <> inline ushort saturate_cast<ushort>(double v) {
  int iv = cvRound(v);
  return saturate_cast<ushort>(iv);
}
template <> inline ushort saturate_cast<ushort>(int64 v) {
  return (ushort)((uint64)v <= (uint64)USHRT_MAX ? v : v > 0 ? USHRT_MAX : 0);
}
template <> inline ushort saturate_cast<ushort>(uint64 v) {
  return (ushort)std::min(v, (uint64)USHRT_MAX);
}

template <> inline short saturate_cast<short>(ushort v) {
  return (short)std::min((int)v, SHRT_MAX);
}
template <> inline short saturate_cast<short>(int v) {
  return (short)((unsigned)(v - SHRT_MIN) <= (unsigned)USHRT_MAX ? v
                 : v > 0                                         ? SHRT_MAX
                                                                 : SHRT_MIN);
}
template <> inline short saturate_cast<short>(unsigned v) {
  return (short)std::min(v, (unsigned)SHRT_MAX);
}
template <> inline short saturate_cast<short>(float v) {
  int iv = cvRound(v);
  return saturate_cast<short>(iv);
}
template <> inline short saturate_cast<short>(double v) {
  int iv = cvRound(v);
  return saturate_cast<short>(iv);
}
template <> inline short saturate_cast<short>(int64 v) {
  return (short)((uint64)((int64)v - SHRT_MIN) <= (uint64)USHRT_MAX ? v
                 : v > 0                                            ? SHRT_MAX
                                                                    : SHRT_MIN);
}
template <> inline short saturate_cast<short>(uint64 v) {
  return (short)std::min(v, (uint64)SHRT_MAX);
}

template <> inline int saturate_cast<int>(unsigned v) {
  return (int)std::min(v, (unsigned)INT_MAX);
}
template <> inline int saturate_cast<int>(int64 v) {
  return (int)((uint64)(v - INT_MIN) <= (uint64)UINT_MAX ? v
               : v > 0                                   ? INT_MAX
                                                         : INT_MIN);
}
template <> inline int saturate_cast<int>(uint64 v) {
  return (int)std::min(v, (uint64)INT_MAX);
}
template <> inline int saturate_cast<int>(float v) { return cvRound(v); }
template <> inline int saturate_cast<int>(double v) { return cvRound(v); }

template <> inline unsigned saturate_cast<unsigned>(schar v) {
  return (unsigned)std::max(v, (schar)0);
}
template <> inline unsigned saturate_cast<unsigned>(short v) {
  return (unsigned)std::max(v, (short)0);
}
template <> inline unsigned saturate_cast<unsigned>(int v) {
  return (unsigned)std::max(v, (int)0);
}
template <> inline unsigned saturate_cast<unsigned>(int64 v) {
  return (unsigned)((uint64)v <= (uint64)UINT_MAX ? v : v > 0 ? UINT_MAX : 0);
}
template <> inline unsigned saturate_cast<unsigned>(uint64 v) {
  return (unsigned)std::min(v, (uint64)UINT_MAX);
}
// we intentionally do not clip negative numbers, to make -1 become 0xffffffff
// etc.
template <> inline unsigned saturate_cast<unsigned>(float v) {
  return static_cast<unsigned>(cvRound(v));
}
template <> inline unsigned saturate_cast<unsigned>(double v) {
  return static_cast<unsigned>(cvRound(v));
}

template <> inline uint64 saturate_cast<uint64>(schar v) {
  return (uint64)std::max(v, (schar)0);
}
template <> inline uint64 saturate_cast<uint64>(short v) {
  return (uint64)std::max(v, (short)0);
}
template <> inline uint64 saturate_cast<uint64>(int v) {
  return (uint64)std::max(v, (int)0);
}
template <> inline uint64 saturate_cast<uint64>(int64 v) {
  return (uint64)std::max(v, (int64)0);
}

template <> inline int64 saturate_cast<int64>(uint64 v) {
  return (int64)std::min(v, (uint64)LLONG_MAX);
}

/** @overload */
template <typename _Tp> static inline _Tp saturate_cast(hfloat v) {
  return saturate_cast<_Tp>((float)v);
}

// in theory, we could use a LUT for 8u/8s->16f conversion,
// but with hardware support for FP32->FP16 conversion the current approach is
// preferable
template <> inline hfloat saturate_cast<hfloat>(uchar v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(schar v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(ushort v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(short v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(unsigned v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(int v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(uint64 v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(int64 v) {
  return hfloat((float)v);
}
template <> inline hfloat saturate_cast<hfloat>(float v) { return hfloat(v); }
template <> inline hfloat saturate_cast<hfloat>(double v) {
  return hfloat((float)v);
}

//! @}

} // namespace cv

#endif // OPENCV_CORE_SATURATE_HPP