saturate_cast.hpp

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#ifndef CAROTENE_SATURATE_CAST_HPP
#define CAROTENE_SATURATE_CAST_HPP

#include <algorithm>
#include <climits>
#include <cmath>

#if defined _MSC_VER && defined _M_ARM
# include <intrin.h>
#endif

#include <carotene/definitions.hpp>
#include <carotene/types.hpp>

namespace CAROTENE_NS { namespace internal {

#if defined _MSC_VER && defined _M_ARM

__declspec(naked) static void vcvtr_s32_f64_imp(f64 d)
{
    (void)d;
    __emit(0xEEBD);  // vcvtr.s32.f64 s0, d0
    __emit(0x0B40);
    __emit(0xEE10);  // vmov r0, s0
    __emit(0x0A10);
    __emit(0x4770);  // bx lr
}

# define CAROTENE_ROUND_FLT(x) return ((s32 (*)(f64))vcvtr_s32_f64_imp)((f64)x);
# define CAROTENE_ROUND_DBL(x) return ((s32 (*)(f64))vcvtr_s32_f64_imp)(x);

#elif defined CV_ICC || defined __GNUC__

# if defined(__VFP_FP__) && !defined(__SOFTFP__) && !(defined _DEBUG || defined DEBUG) && !defined(__CUDACC__)
#  define CAROTENE_ROUND_FLT(value) {                              \
    union { f32 f; s32 i; } result; \
    asm ("ftosis  %0, %1 \n" : "=w" (result.f) : "w" (value) ); \
    return result.i; }
#  define CAROTENE_ROUND_DBL(value) {                      \
    union {f32 f; s32 i;} __tegra_result; \
    asm (                                               \
        "ftosid  %0, %P1\n"                             \
        : "=w" (__tegra_result.f)                       \
        : "w" (value)                                   \
    );                                                  \
    return __tegra_result.i;                            \
    }
# else
#  define CAROTENE_ROUND_FLT(x) return (s32)lrintf(value);
#  define CAROTENE_ROUND_DBL(value) return (s32)lrint(value);
# endif

#endif

inline s32 round(f32 value)
{
#ifdef CAROTENE_ROUND_FLT
    CAROTENE_ROUND_FLT(value)
#else
    s32 intpart = (s32)(value);
    f32 fractpart = value - intpart;
    if ((fractpart != 0.5 && fractpart != -0.5) || ((intpart % 2) != 0))
        return (s32)(value + (value >= 0 ? 0.5 : -0.5));
    else
        return intpart;
#endif
}

inline s32 round(f64 value)
{
#ifdef CAROTENE_ROUND_DBL
    CAROTENE_ROUND_DBL(value)
#else
    s32 intpart = (s32)(value);
    f64 fractpart = value - intpart;
    if ((fractpart != 0.5 && fractpart != -0.5) || ((intpart % 2) != 0))
        return (s32)(value + (value >= 0 ? 0.5 : -0.5));
    else
        return intpart;
#endif
}
/////////////// saturate_cast (used in image & signal processing) ///////////////////

template<typename _Tp> inline _Tp saturate_cast(u8 v)    { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(s8 v)    { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(u16 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(s16 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(u32 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(s32 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(s64 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(u64 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(f32 v)   { return _Tp(v); }
template<typename _Tp> inline _Tp saturate_cast(f64 v)   { return _Tp(v); }

template<> inline u8 saturate_cast<u8>(s8 v)      { return (u8)std::max((s32)v, 0); }
template<> inline u8 saturate_cast<u8>(u16 v)     { return (u8)std::min((u32)v, (u32)UCHAR_MAX); }
template<> inline u8 saturate_cast<u8>(s32 v)     { return (u8)((u32)v <= UCHAR_MAX ? v : v > 0 ? UCHAR_MAX : 0); }
template<> inline u8 saturate_cast<u8>(s16 v)     { return saturate_cast<u8>((s32)v); }
template<> inline u8 saturate_cast<u8>(u32 v)     { return (u8)std::min(v, (u32)UCHAR_MAX); }
template<> inline u8 saturate_cast<u8>(s64 v)     { return (u8)((u64)v <= UCHAR_MAX ? v : v > 0 ? UCHAR_MAX : 0); }
template<> inline u8 saturate_cast<u8>(u64 v)     { return (u8)std::min(v, (u64)UCHAR_MAX); }
template<> inline u8 saturate_cast<u8>(f32 v)     { return saturate_cast<u8>(round(v)); }
template<> inline u8 saturate_cast<u8>(f64 v)     { return saturate_cast<u8>(round(v)); }

template<> inline s8 saturate_cast<s8>(u8 v)      { return (s8)std::min((s32)v, SCHAR_MAX); }
template<> inline s8 saturate_cast<s8>(u16 v)     { return (s8)std::min((u32)v, (u32)SCHAR_MAX); }
template<> inline s8 saturate_cast<s8>(s32 v)     { return (s8)((u32)(v-SCHAR_MIN) <= (u32)UCHAR_MAX ? v : v > 0 ? SCHAR_MAX : SCHAR_MIN); }
template<> inline s8 saturate_cast<s8>(s16 v)     { return saturate_cast<s8>((s32)v); }
template<> inline s8 saturate_cast<s8>(u32 v)     { return (s8)std::min(v, (u32)SCHAR_MAX); }
template<> inline s8 saturate_cast<s8>(s64 v)     { return (s8)((u64)(v-SCHAR_MIN) <= (u64)UCHAR_MAX ? v : v > 0 ? SCHAR_MAX : SCHAR_MIN); }
template<> inline s8 saturate_cast<s8>(u64 v)     { return (s8)std::min(v, (u64)SCHAR_MAX); }
template<> inline s8 saturate_cast<s8>(f32 v)     { return saturate_cast<s8>(round(v)); }
template<> inline s8 saturate_cast<s8>(f64 v)     { return saturate_cast<s8>(round(v)); }

template<> inline u16 saturate_cast<u16>(s8 v)    { return (u16)std::max((s32)v, 0); }
template<> inline u16 saturate_cast<u16>(s16 v)   { return (u16)std::max((s32)v, 0); }
template<> inline u16 saturate_cast<u16>(s32 v)   { return (u16)((u32)v <= (u32)USHRT_MAX ? v : v > 0 ? USHRT_MAX : 0); }
template<> inline u16 saturate_cast<u16>(u32 v)   { return (u16)std::min(v, (u32)USHRT_MAX); }
template<> inline u16 saturate_cast<u16>(s64 v)   { return (u16)((u64)v <= (u64)USHRT_MAX ? v : v > 0 ? USHRT_MAX : 0); }
template<> inline u16 saturate_cast<u16>(u64 v)   { return (u16)std::min(v, (u64)USHRT_MAX); }
template<> inline u16 saturate_cast<u16>(f32 v)   { return saturate_cast<u16>(round(v)); }
template<> inline u16 saturate_cast<u16>(f64 v)   { return saturate_cast<u16>(round(v)); }

template<> inline s16 saturate_cast<s16>(u16 v)   { return (s16)std::min((s32)v, SHRT_MAX); }
template<> inline s16 saturate_cast<s16>(s32 v)   { return (s16)((u32)(v - SHRT_MIN) <= (u32)USHRT_MAX ? v : v > 0 ? SHRT_MAX : SHRT_MIN); }
template<> inline s16 saturate_cast<s16>(u32 v)   { return (s16)std::min(v, (u32)SHRT_MAX); }
template<> inline s16 saturate_cast<s16>(s64 v)   { return (s16)((u64)(v - SHRT_MIN) <= (u64)USHRT_MAX ? v : v > 0 ? SHRT_MAX : SHRT_MIN); }
template<> inline s16 saturate_cast<s16>(u64 v)   { return (s16)std::min(v, (u64)SHRT_MAX); }
template<> inline s16 saturate_cast<s16>(f32 v)   { return saturate_cast<s16>(round(v)); }
template<> inline s16 saturate_cast<s16>(f64 v)   { return saturate_cast<s16>(round(v)); }

template<> inline u32 saturate_cast<u32>(s8 v)    { return (u32)std::max(v, (s8)0); }
template<> inline u32 saturate_cast<u32>(s16 v)   { return (u32)std::max(v, (s16)0); }
template<> inline u32 saturate_cast<u32>(s32 v)   { return (u32)std::max(v, (s32)0); }
template<> inline u32 saturate_cast<u32>(s64 v)   { return (u32)((u64)v <= (u64)UINT_MAX ? v : v > 0 ? UINT_MAX : 0); }
template<> inline u32 saturate_cast<u32>(u64 v)   { return (u32)std::min(v, (u64)UINT_MAX); }
//OpenCV like f32/f64 -> u32 conversion
//we intentionally do not clip negative numbers, to make -1 become 0xffffffff etc.
template<> inline u32 saturate_cast<u32>(f32 v)   { return round(v); }
template<> inline u32 saturate_cast<u32>(f64 v)   { return round(v); }
//Negative clipping implementation
//template<> inline u32 saturate_cast<u32>(f32 v)   { return saturate_cast<u32>(round(v)); }
//template<> inline u32 saturate_cast<u32>(f64 v)   { return saturate_cast<u32>(round(v)); }

template<> inline s32 saturate_cast<s32>(u32 v)   { return (s32)std::min(v, (u32)INT_MAX); }
template<> inline s32 saturate_cast<s32>(s64 v)   { return (s32)((u64)(v - INT_MIN) <= (u64)UINT_MAX ? v : v > 0 ? INT_MAX : INT_MIN); }
template<> inline s32 saturate_cast<s32>(u64 v)   { return (s32)std::min(v, (u64)INT_MAX); }
template<> inline s32 saturate_cast<s32>(f32 v)   { return round(v); }
template<> inline s32 saturate_cast<s32>(f64 v)   { return round(v); }

template<> inline u64 saturate_cast<u64>(s8 v)    { return (u64)std::max(v, (s8)0); }
template<> inline u64 saturate_cast<u64>(s16 v)   { return (u64)std::max(v, (s16)0); }
template<> inline u64 saturate_cast<u64>(s32 v)   { return (u64)std::max(v, (s32)0); }
template<> inline u64 saturate_cast<u64>(s64 v)   { return (u64)std::max(v, (s64)0); }

template<> inline s64 saturate_cast<s64>(u64 v)   { return (s64)std::min(v, (u64)LLONG_MAX); }

} }

#endif