sol2/sol/variadic_args.hpp

// The MIT License (MIT) 

// Copyright (c) 2013-2016 Rapptz, ThePhD and contributors

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_VARIADIC_ARGS_HPP
#define SOL_VARIADIC_ARGS_HPP

#include "stack.hpp"
#include "stack_proxy.hpp"
#include <iterator>

namespace sol {
	struct va_iterator : std::iterator<std::random_access_iterator_tag, stack_proxy, std::ptrdiff_t, stack_proxy*, stack_proxy> {
		lua_State* L;
		int index;
		int stacktop;
		stack_proxy sp;

		va_iterator() : L(nullptr), index(std::numeric_limits<int>::max()), stacktop(std::numeric_limits<int>::max()) {}
		va_iterator(lua_State* L, int index, int stacktop) : L(L), index(index), stacktop(stacktop), sp(L, index) {}

		stack_proxy operator*() {
			sp = stack_proxy(L, index);
			return sp;
		}

		stack_proxy* operator->() {
			sp = stack_proxy(L, index);
			return &sp;
		}

		va_iterator& operator++ () {
			++index;
			return *this;
		}

		va_iterator operator++ (int) {
			auto r = *this;
			this->operator ++();
			return r;
		}

		va_iterator& operator-- () {
			--index;
			return *this;
		}

		va_iterator operator-- (int) {
			auto r = *this;
			this->operator --();
			return r;
		}

		va_iterator& operator+= (difference_type idx) {
			index += static_cast<int>(idx);
			return *this;
		}

		va_iterator& operator-= (difference_type idx) {
			index -= static_cast<int>(idx);
			return *this;
		}

		difference_type operator- (const va_iterator& r) const {
			return index - r.index;
		}

		va_iterator operator+ (difference_type idx) const {
			va_iterator r = *this;
			r += idx;
			return r;
		}

		stack_proxy operator[](difference_type idx) {
			return stack_proxy(L, index + static_cast<int>(idx));
		}

		bool operator==(const va_iterator& r) const {
			if (stacktop == std::numeric_limits<int>::max()) {
				return r.index == r.stacktop;
			}
			else if (r.stacktop == std::numeric_limits<int>::max()) {
				return index == stacktop;
			}
			return index == r.index;
		}

		bool operator != (const va_iterator& r) const {
			return !(this->operator==(r));
		}

		bool operator < (const va_iterator& r) const {
			return index < r.index;
		}

		bool operator > (const va_iterator& r) const {
			return index > r.index;
		}

		bool operator <= (const va_iterator& r) const {
			return index <= r.index;
		}

		bool operator >= (const va_iterator& r) const {
			return index >= r.index;
		}
	};

	inline va_iterator operator+(typename va_iterator::difference_type n, const va_iterator& r) {
		return r + n;
	}

struct variadic_args {
private:
    lua_State* L;
    int index;
    int stacktop;

public:
    typedef stack_proxy reference_type;
    typedef stack_proxy value_type;
    typedef stack_proxy* pointer;
    typedef std::ptrdiff_t difference_type;
    typedef std::size_t size_type;
    typedef va_iterator iterator;
    typedef const va_iterator const_iterator;
    typedef std::reverse_iterator<iterator> reverse_iterator;
    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

    variadic_args() = default;
    variadic_args(lua_State* L, int index = -1): L(L), index(lua_absindex(L, index)), stacktop(lua_gettop(L)) {}
    variadic_args(const variadic_args&) = default;
    variadic_args& operator=(const variadic_args&) = default;
    variadic_args(variadic_args&& o) : L(o.L), index(o.index), stacktop(o.stacktop) {
        // Must be manual, otherwise destructor will screw us
        // return count being 0 is enough to keep things clean
        // but will be thorough
        o.L = nullptr;
        o.index = 0;
        o.stacktop = 0;
    }
    variadic_args& operator=(variadic_args&& o) {
        L = o.L;
        index = o.index;
        stacktop = o.stacktop;
        // Must be manual, otherwise destructor will screw us
        // return count being 0 is enough to keep things clean
        // but will be thorough
        o.L = nullptr;
        o.index = 0;
        o.stacktop = 0;
        return *this;
    }

    iterator begin() { return va_iterator(L, index, stacktop + 1); }
    iterator end() { return va_iterator(L, stacktop + 1, stacktop + 1); }
    const_iterator begin() const { return va_iterator(L, index, stacktop + 1); }
    const_iterator end() const { return va_iterator(L, stacktop + 1, stacktop + 1); }
    const_iterator cbegin() const { return begin(); }
    const_iterator cend() const { return end(); }

    reverse_iterator rbegin() { return std::make_reverse_iterator(begin()); }
    reverse_iterator rend() { return std::make_reverse_iterator(end()); }
    const_reverse_iterator rbegin() const { return std::make_reverse_iterator(begin()); }
    const_reverse_iterator rend() const { return std::make_reverse_iterator(end()); }
    const_reverse_iterator crbegin() const { return std::make_reverse_iterator(cbegin()); }
    const_reverse_iterator crend() const { return std::make_reverse_iterator(cend()); }

    int push () const {
        int pushcount = 0;
        for (int i = index; i <= stacktop; ++i) {
            lua_pushvalue(L, i);
            pushcount += 1;
        }
        return pushcount;
    }

    template<typename T>
    decltype(auto) get(difference_type start = 0) const {
        return stack::get<T>(L, index + static_cast<int>(start));
    }

    stack_proxy operator[](difference_type start) const {
        return stack_proxy(L, index + static_cast<int>(start));
    }

    lua_State* lua_state() const { return L; };
    int stack_index() const { return index; };
    int leftover_count() const { return stacktop - (index - 1); }
    int top() const { return stacktop; }
};

namespace stack {
template <>
struct getter<variadic_args> {
    static variadic_args get(lua_State* L, int index = -1) {
        return variadic_args(L, index);
    }
};

template <>
struct pusher<variadic_args> {
    static int push(lua_State*, const variadic_args& ref) {
        return ref.push();
    }
};
} // stack
} // sol

#endif // SOL_VARIADIC_ARGS_HPP