//===----------------------------------------------------------------------===//
//
// Part of libcu++, the C++ Standard Library for your entire system,
// under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

#if defined(__GNUC__)
#  pragma GCC system_header
#endif

// For all compilers and dialects this header defines:
//  _NV_EVAL
//  _NV_IF
//  _NV_CONCAT_EVAL
// For C++11 and up it defines:
//  _NV_STRIP_PAREN
//  _NV_DISPATCH_N_ARY
//  _NV_FIRST_ARG
//  _NV_REMOVE_PAREN

#if defined(_NV_TARGET_CPP11)
#  define _NV_EVAL1(...) __VA_ARGS__
#  define _NV_EVAL(...)  _NV_EVAL1(__VA_ARGS__)
#else
#  define _NV_EVAL1(x) x
#  define _NV_EVAL(x)  _NV_EVAL1(x)
#endif // C++11

#define _NV_CONCAT_EVAL1(l, r) _NV_EVAL(l##r)
#define _NV_CONCAT_EVAL(l, r)  _NV_CONCAT_EVAL1(l, r)

#define _NV_IF_0(t, f) f
#define _NV_IF_1(t, f) t

#define _NV_IF_BIT(b)           _NV_EVAL(_NV_IF_##b)
#define _NV_IF__EVAL(fn, t, f)  _NV_EVAL(fn(t, f))
#define _NV_IF_EVAL(cond, t, f) _NV_IF__EVAL(_NV_IF_BIT(cond), t, f)

#define _NV_IF1(cond, t, f) _NV_IF_EVAL(cond, t, f)
#define _NV_IF(cond, t, f)  _NV_IF1(_NV_EVAL(cond), _NV_EVAL(t), _NV_EVAL(f))

#if defined(_NV_TARGET_CPP11)

// The below mechanisms were derived from: https://gustedt.wordpress.com/2010/06/08/detect-empty-macro-arguments/

#  define _NV_ARG32(...) _NV_EVAL(_NV_ARG32_0(__VA_ARGS__))
#  define _NV_ARG32_0( \
    _0,                \
    _1,                \
    _2,                \
    _3,                \
    _4,                \
    _5,                \
    _6,                \
    _7,                \
    _8,                \
    _9,                \
    _10,               \
    _11,               \
    _12,               \
    _13,               \
    _14,               \
    _15,               \
    _16,               \
    _17,               \
    _18,               \
    _19,               \
    _20,               \
    _21,               \
    _22,               \
    _23,               \
    _24,               \
    _25,               \
    _26,               \
    _27,               \
    _28,               \
    _29,               \
    _30,               \
    _31,               \
    ...)               \
    _31

#  define _NV_HAS_COMMA(...) \
    _NV_ARG32(__VA_ARGS__, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)

#  define _NV_TRIGGER_PARENTHESIS_(...) ,

#  define _NV_ISEMPTY(...)                                                                                            \
    _NV_ISEMPTY0(/* test if there is just one argument, eventually an empty                                           \
                    one */                                                                                            \
                 _NV_EVAL(_NV_HAS_COMMA(__VA_ARGS__)), /* test if _TRIGGER_PARENTHESIS_ together with the argument    \
                                                          adds a comma */                                             \
                 _NV_EVAL(_NV_HAS_COMMA(_NV_TRIGGER_PARENTHESIS_ __VA_ARGS__)), /* test if the argument together with \
                                                                                   a parenthesis adds a comma */      \
                 _NV_EVAL(_NV_HAS_COMMA(__VA_ARGS__(/*empty*/))), /* test if placing it between _TRIGGER_PARENTHESIS_ \
                                                                     and the parenthesis adds a comma */              \
                 _NV_EVAL(_NV_HAS_COMMA(_NV_TRIGGER_PARENTHESIS_ __VA_ARGS__(/*empty*/))))

#  define _NV_PASTE5(_0, _1, _2, _3, _4) _0##_1##_2##_3##_4
#  define _NV_ISEMPTY0(_0, _1, _2, _3)   _NV_HAS_COMMA(_NV_PASTE5(_NV_IS_EMPTY_CASE_, _0, _1, _2, _3))
#  define _NV_IS_EMPTY_CASE_0001         ,

#  define _NV_REMOVE_PAREN(...) _NV_REMOVE_PAREN1(__VA_ARGS__)
#  define _NV_REMOVE_PAREN1(...) \
    _NV_STRIP_PAREN(_NV_IF(_NV_TEST_PAREN(__VA_ARGS__), (_NV_STRIP_PAREN(__VA_ARGS__)), (__VA_ARGS__)))

#  define _NV_STRIP_PAREN2(...) __VA_ARGS__
#  define _NV_STRIP_PAREN1(...) _NV_STRIP_PAREN2 __VA_ARGS__
#  define _NV_STRIP_PAREN(...)  _NV_STRIP_PAREN1(__VA_ARGS__)

#  define _NV_TEST_PAREN(...)  _NV_TEST_PAREN1(__VA_ARGS__)
#  define _NV_TEST_PAREN1(...) _NV_TEST_PAREN2(_NV_TEST_PAREN_DUMMY __VA_ARGS__)
#  define _NV_TEST_PAREN2(...) _NV_TEST_PAREN3(_NV_CONCAT_EVAL(_, __VA_ARGS__))
#  define _NV_TEST_PAREN3(...) _NV_EVAL(_NV_FIRST_ARG(__VA_ARGS__))

#  define __NV_PAREN_YES 1
#  define __NV_PAREN_NO  0

#  define _NV_TEST_PAREN_DUMMY(...) _NV_PAREN_YES
#  define __NV_TEST_PAREN_DUMMY     __NV_PAREN_NO,

#  define _NV_FIRST_ARG1(x, ...) x
#  define _NV_FIRST_ARG(x, ...)  _NV_FIRST_ARG1(x)

#  define _NV_REMOVE_FIRST_ARGS1(...)   __VA_ARGS__
#  define _NV_REMOVE_FIRST_ARGS(x, ...) _NV_REMOVE_FIRST_ARGS1(__VA_ARGS__)

#  define _NV_NUM_ARGS(...)  _NV_NUM_ARGS0(__VA_ARGS__)
#  define _NV_NUM_ARGS0(...) _NV_EVAL(_NV_NUM_ARGS1(__VA_ARGS__))
#  define _NV_NUM_ARGS1(...) _NV_IF(_NV_ISEMPTY(__VA_ARGS__), 0, _NV_NUM_ARGS2(__VA_ARGS__))
#  define _NV_NUM_ARGS2(...) \
    _NV_ARG32(               \
      __VA_ARGS__,           \
      31,                    \
      30,                    \
      29,                    \
      28,                    \
      27,                    \
      26,                    \
      25,                    \
      24,                    \
      23,                    \
      22,                    \
      21,                    \
      20,                    \
      19,                    \
      18,                    \
      17,                    \
      16,                    \
      15,                    \
      14,                    \
      13,                    \
      12,                    \
      11,                    \
      10,                    \
      9,                     \
      8,                     \
      7,                     \
      6,                     \
      5,                     \
      4,                     \
      3,                     \
      2,                     \
      1,                     \
      0)

#  define _NV_DISPATCH_N_IMPL1(name, ...)        _NV_EVAL(name(__VA_ARGS__))
#  define _NV_DISPATCH_N_IMPL0(depth, name, ...) _NV_DISPATCH_N_IMPL1(_NV_CONCAT_EVAL(name, depth), __VA_ARGS__)
#  define _NV_DISPATCH_N_IMPL(name, ...)         _NV_DISPATCH_N_IMPL0(_NV_NUM_ARGS(__VA_ARGS__), name, __VA_ARGS__)
#  define _NV_DISPATCH_N_ARY(name, ...)          _NV_DISPATCH_N_IMPL(name, __VA_ARGS__)

#endif // C++11
