//
// Copyright (c) 2017 The Khronos Group Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

// Disclaimer:
// This code is based on the work found in OpenCL-CTS authored by The Khronos Group.
// The original code can be found at https://github.com/KhronosGroup/OpenCL-CTS.
// We acknowledge the contributions of The Khronos Group to the development of this code.

#pragma once

#include <array>
#include <limits>

/*-----------------------------------------------------------------------------
   HEX_FLT, HEXT_DBL, HEX_LDBL -- Create hex floating point literal of type
   float, double, long double respectively. Arguments:

      sm    -- sign of number,
      int   -- integer part of mantissa (without `0x' prefix),
      fract -- fractional part of mantissa (without decimal point and `L' or
            `LL' suffixes),
      se    -- sign of exponent,
      exp   -- absolute value of (binary) exponent.

   Example:

      double yhi = HEX_DBL(+, 1, 5555555555555, -, 2); // 0x1.5555555555555p-2

   Note:

      We have to pass signs as separate arguments because gcc pass negative
   integer values (e. g. `-2') into a macro as two separate tokens, so
   `HEX_FLT(1, 0, -2)' produces result `0x1.0p- 2' (note a space between minus
   and two) which is not a correct floating point literal.
-----------------------------------------------------------------------------*/
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
// If compiler does not support hex floating point literals:
#define HEX_FLT(sm, int, fract, se, exp)                                                           \
  sm ldexpf((float)(0x##int##fract##UL),                                                           \
            se exp + ilogbf((float)0x##int) - ilogbf((float)(0x##int##fract##UL)))
#define HEX_DBL(sm, int, fract, se, exp)                                                           \
  sm ldexp((double)(0x##int##fract##ULL),                                                          \
           se exp + ilogb((double)0x##int) - ilogb((double)(0x##int##fract##ULL)))
#define HEX_LDBL(sm, int, fract, se, exp)                                                          \
  sm ldexpl((long double)(0x##int##fract##ULL),                                                    \
            se exp + ilogbl((long double)0x##int) - ilogbl((long double)(0x##int##fract##ULL)))
#else
// If compiler supports hex floating point literals: just concatenate all the
// parts into a literal.
#define HEX_FLT(sm, int, fract, se, exp) sm 0x##int##.##fract##p##se##exp##F
#define HEX_DBL(sm, int, fract, se, exp) sm 0x##int##.##fract##p##se##exp
#define HEX_LDBL(sm, int, fract, se, exp) sm 0x##int##.##fract##p##se##exp##L
#endif

inline constexpr std::array kSpecialValuesDouble{
    -std::numeric_limits<double>::quiet_NaN(),
    -std::numeric_limits<double>::infinity(),
    -std::numeric_limits<double>::max(),
    HEX_DBL(-, 1, 0000000000001, +, 64),
    HEX_DBL(-, 1, 0, +, 64),
    HEX_DBL(-, 1, fffffffffffff, +, 63),
    HEX_DBL(-, 1, 0000000000001, +, 63),
    HEX_DBL(-, 1, 0, +, 63),
    HEX_DBL(-, 1, fffffffffffff, +, 62),
    HEX_DBL(-, 1, 000002, +, 32),
    HEX_DBL(-, 1, 0, +, 32),
    HEX_DBL(-, 1, fffffffffffff, +, 31),
    HEX_DBL(-, 1, 0000000000001, +, 31),
    HEX_DBL(-, 1, 0, +, 31),
    HEX_DBL(-, 1, fffffffffffff, +, 30),
    -1000.0,
    -100.0,
    -4.0,
    -3.5,
    -3.0,
    HEX_DBL(-, 1, 8000000000001, +, 1),
    -2.5,
    HEX_DBL(-, 1, 7ffffffffffff, +, 1),
    -2.0,
    HEX_DBL(-, 1, 8000000000001, +, 0),
    -1.5,
    HEX_DBL(-, 1, 7ffffffffffff, +, 0),
    HEX_DBL(-, 1, 0000000000001, +, 0),
    -1.0,
    HEX_DBL(-, 1, fffffffffffff, -, 1),
    HEX_DBL(-, 1, 0000000000001, -, 1),
    -0.5,
    HEX_DBL(-, 1, fffffffffffff, -, 2),
    HEX_DBL(-, 1, 0000000000001, -, 2),
    -0.25,
    HEX_DBL(-, 1, fffffffffffff, -, 3),
    HEX_DBL(-, 1, 0000000000001, -, 1022),
    -std::numeric_limits<double>::min(),
    HEX_DBL(-, 0, fffffffffffff, -, 1022),
    HEX_DBL(-, 0, 0000000000fff, -, 1022),
    HEX_DBL(-, 0, 00000000000fe, -, 1022),
    HEX_DBL(-, 0, 000000000000e, -, 1022),
    HEX_DBL(-, 0, 000000000000c, -, 1022),
    HEX_DBL(-, 0, 000000000000a, -, 1022),
    HEX_DBL(-, 0, 0000000000008, -, 1022),
    HEX_DBL(-, 0, 0000000000007, -, 1022),
    HEX_DBL(-, 0, 0000000000006, -, 1022),
    HEX_DBL(-, 0, 0000000000005, -, 1022),
    HEX_DBL(-, 0, 0000000000004, -, 1022),
    HEX_DBL(-, 0, 0000000000003, -, 1022),
    HEX_DBL(-, 0, 0000000000002, -, 1022),
    HEX_DBL(-, 0, 0000000000001, -, 1022),
    -0.0,

    std::numeric_limits<double>::quiet_NaN(),
    std::numeric_limits<double>::infinity(),
    std::numeric_limits<double>::max(),
    HEX_DBL(+, 1, 0000000000001, +, 64),
    HEX_DBL(+, 1, 0, +, 64),
    HEX_DBL(+, 1, fffffffffffff, +, 63),
    HEX_DBL(+, 1, 0000000000001, +, 63),
    HEX_DBL(+, 1, 0, +, 63),
    HEX_DBL(+, 1, fffffffffffff, +, 62),
    HEX_DBL(+, 1, 000002, +, 32),
    HEX_DBL(+, 1, 0, +, 32),
    HEX_DBL(+, 1, fffffffffffff, +, 31),
    HEX_DBL(+, 1, 0000000000001, +, 31),
    HEX_DBL(+, 1, 0, +, 31),
    HEX_DBL(+, 1, fffffffffffff, +, 30),
    +1000.0,
    +100.0,
    +4.0,
    +3.5,
    +3.0,
    HEX_DBL(+, 1, 8000000000001, +, 1),
    +2.5,
    HEX_DBL(+, 1, 7ffffffffffff, +, 1),
    +2.0,
    HEX_DBL(+, 1, 8000000000001, +, 0),
    +1.5,
    HEX_DBL(+, 1, 7ffffffffffff, +, 0),
    HEX_DBL(+, 1, 0000000000001, +, 0),
    +1.0,
    HEX_DBL(+, 1, fffffffffffff, -, 1),
    HEX_DBL(+, 1, 0000000000001, -, 1),
    +0.5,
    HEX_DBL(+, 1, fffffffffffff, -, 2),
    HEX_DBL(+, 1, 0000000000001, -, 2),
    +0.25,
    HEX_DBL(+, 1, fffffffffffff, -, 3),
    HEX_DBL(+, 1, 0000000000001, -, 1022),
    +std::numeric_limits<double>::min(),
    HEX_DBL(+, 0, fffffffffffff, -, 1022),
    HEX_DBL(+, 0, 0000000000fff, -, 1022),
    HEX_DBL(+, 0, 00000000000fe, -, 1022),
    HEX_DBL(+, 0, 000000000000e, -, 1022),
    HEX_DBL(+, 0, 000000000000c, -, 1022),
    HEX_DBL(+, 0, 000000000000a, -, 1022),
    HEX_DBL(+, 0, 0000000000008, -, 1022),
    HEX_DBL(+, 0, 0000000000007, -, 1022),
    HEX_DBL(+, 0, 0000000000006, -, 1022),
    HEX_DBL(+, 0, 0000000000005, -, 1022),
    HEX_DBL(+, 0, 0000000000004, -, 1022),
    HEX_DBL(+, 0, 0000000000003, -, 1022),
    HEX_DBL(+, 0, 0000000000002, -, 1022),
    HEX_DBL(+, 0, 0000000000001, -, 1022),
    +0.0,
};

inline constexpr std::array kSpecialValuesFloat{
    -std::numeric_limits<float>::quiet_NaN(),
    -std::numeric_limits<float>::infinity(),
    -std::numeric_limits<float>::max(),
    HEX_FLT(-, 1, 000002, +, 64),
    HEX_FLT(-, 1, 0, +, 64),
    HEX_FLT(-, 1, fffffe, +, 63),
    HEX_FLT(-, 1, 000002, +, 63),
    HEX_FLT(-, 1, 0, +, 63),
    HEX_FLT(-, 1, fffffe, +, 62),
    HEX_FLT(-, 1, 000002, +, 32),
    HEX_FLT(-, 1, 0, +, 32),
    HEX_FLT(-, 1, fffffe, +, 31),
    HEX_FLT(-, 1, 000002, +, 31),
    HEX_FLT(-, 1, 0, +, 31),
    HEX_FLT(-, 1, fffffe, +, 30),
    -1000.f,
    -100.f,
    -4.0f,
    -3.5f,
    -3.0f,
    HEX_FLT(-, 1, 800002, +, 1),
    -2.5f,
    HEX_FLT(-, 1, 7ffffe, +, 1),
    -2.0f,
    HEX_FLT(-, 1, 800002, +, 0),
    -1.5f,
    HEX_FLT(-, 1, 7ffffe, +, 0),
    HEX_FLT(-, 1, 000002, +, 0),
    -1.0f,
    HEX_FLT(-, 1, fffffe, -, 1),
    HEX_FLT(-, 1, 000002, -, 1),
    -0.5f,
    HEX_FLT(-, 1, fffffe, -, 2),
    HEX_FLT(-, 1, 000002, -, 2),
    -0.25f,
    HEX_FLT(-, 1, fffffe, -, 3),
    HEX_FLT(-, 1, 000002, -, 126),
    -std::numeric_limits<float>::min(),
    HEX_FLT(-, 0, fffffe, -, 126),
    HEX_FLT(-, 0, 000ffe, -, 126),
    HEX_FLT(-, 0, 0000fe, -, 126),
    HEX_FLT(-, 0, 00000e, -, 126),
    HEX_FLT(-, 0, 00000c, -, 126),
    HEX_FLT(-, 0, 00000a, -, 126),
    HEX_FLT(-, 0, 000008, -, 126),
    HEX_FLT(-, 0, 000006, -, 126),
    HEX_FLT(-, 0, 000004, -, 126),
    HEX_FLT(-, 0, 000002, -, 126),
    -0.0f,

    std::numeric_limits<float>::quiet_NaN(),
    std::numeric_limits<float>::infinity(),
    std::numeric_limits<float>::max(),
    HEX_FLT(+, 1, 000002, +, 64),
    HEX_FLT(+, 1, 0, +, 64),
    HEX_FLT(+, 1, fffffe, +, 63),
    HEX_FLT(+, 1, 000002, +, 63),
    HEX_FLT(+, 1, 0, +, 63),
    HEX_FLT(+, 1, fffffe, +, 62),
    HEX_FLT(+, 1, 000002, +, 32),
    HEX_FLT(+, 1, 0, +, 32),
    HEX_FLT(+, 1, fffffe, +, 31),
    HEX_FLT(+, 1, 000002, +, 31),
    HEX_FLT(+, 1, 0, +, 31),
    HEX_FLT(+, 1, fffffe, +, 30),
    +1000.f,
    +100.f,
    +4.0f,
    +3.5f,
    +3.0f,
    HEX_FLT(+, 1, 800002, +, 1),
    2.5f,
    HEX_FLT(+, 1, 7ffffe, +, 1),
    +2.0f,
    HEX_FLT(+, 1, 800002, +, 0),
    1.5f,
    HEX_FLT(+, 1, 7ffffe, +, 0),
    HEX_FLT(+, 1, 000002, +, 0),
    +1.0f,
    HEX_FLT(+, 1, fffffe, -, 1),
    HEX_FLT(+, 1, 000002, -, 1),
    +0.5f,
    HEX_FLT(+, 1, fffffe, -, 2),
    HEX_FLT(+, 1, 000002, -, 2),
    +0.25f,
    HEX_FLT(+, 1, fffffe, -, 3),
    HEX_FLT(+, 1, 000002, -, 126),
    +std::numeric_limits<float>::min(),
    HEX_FLT(+, 0, fffffe, -, 126),
    HEX_FLT(+, 0, 000ffe, -, 126),
    HEX_FLT(+, 0, 0000fe, -, 126),
    HEX_FLT(+, 0, 00000e, -, 126),
    HEX_FLT(+, 0, 00000c, -, 126),
    HEX_FLT(+, 0, 00000a, -, 126),
    HEX_FLT(+, 0, 000008, -, 126),
    HEX_FLT(+, 0, 000006, -, 126),
    HEX_FLT(+, 0, 000004, -, 126),
    HEX_FLT(+, 0, 000002, -, 126),
    +0.0f,
};

inline constexpr std::array kSpecialValuesInt{
    0, 1, 2, 3, 126, 127, 128, 1022, 1023, 1024, 0x02000001, 0x04000001, 1465264071, 1488522147,
    std::numeric_limits<int>::max(), -1, -2, -3, -126, -127, -128, -1022, -1023, -11024, -0x02000001,
    -0x04000001, -1465264071, -1488522147, std::numeric_limits<int>::min(), -std::numeric_limits<int>::max()
};

template <typename T> struct SpecialVals {
  const T* const data;
  const size_t size;
};

inline constexpr auto kSpecialValRegistry =
    std::make_tuple(SpecialVals<float>{kSpecialValuesFloat.data(), kSpecialValuesFloat.size()},
                    SpecialVals<double>{kSpecialValuesDouble.data(), kSpecialValuesDouble.size()},
                    SpecialVals<int>{kSpecialValuesInt.data(), kSpecialValuesInt.size()});