88 lines
2.1 KiB
C++
88 lines
2.1 KiB
C++
//
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// coroutine.hpp
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// ~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef COROUTINE_HPP
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#define COROUTINE_HPP
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class coroutine
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{
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public:
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coroutine() : value_(0) {}
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bool is_child() const { return value_ < 0; }
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bool is_parent() const { return !is_child(); }
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bool is_complete() const { return value_ == -1; }
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private:
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friend class coroutine_ref;
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int value_;
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};
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class coroutine_ref
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{
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public:
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coroutine_ref(coroutine& c) : value_(c.value_), modified_(false) {}
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coroutine_ref(coroutine* c) : value_(c->value_), modified_(false) {}
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~coroutine_ref() { if (!modified_) value_ = -1; }
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operator int() const { return value_; }
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int& operator=(int v) { modified_ = true; return value_ = v; }
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private:
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void operator=(const coroutine_ref&);
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int& value_;
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bool modified_;
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};
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#define CORO_REENTER(c) \
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switch (coroutine_ref _coro_value = c) \
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case -1: if (_coro_value) \
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{ \
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goto terminate_coroutine; \
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terminate_coroutine: \
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_coro_value = -1; \
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goto bail_out_of_coroutine; \
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bail_out_of_coroutine: \
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break; \
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} \
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else case 0:
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#define CORO_YIELD_IMPL(n) \
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for (_coro_value = (n);;) \
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if (_coro_value == 0) \
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{ \
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case (n): ; \
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break; \
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} \
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else \
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switch (_coro_value ? 0 : 1) \
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for (;;) \
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case -1: if (_coro_value) \
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goto terminate_coroutine; \
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else for (;;) \
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case 1: if (_coro_value) \
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goto bail_out_of_coroutine; \
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else case 0:
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#define CORO_FORK_IMPL(n) \
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for (_coro_value = -(n);; _coro_value = (n)) \
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if (_coro_value == (n)) \
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{ \
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case -(n): ; \
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break; \
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} \
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else
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#if defined(_MSC_VER)
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# define CORO_YIELD CORO_YIELD_IMPL(__COUNTER__ + 1)
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# define CORO_FORK CORO_FORK_IMPL(__COUNTER__ + 1)
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#else // defined(_MSC_VER)
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# define CORO_YIELD CORO_YIELD_IMPL(__LINE__)
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# define CORO_FORK CORO_FORK_IMPL(__LINE__)
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#endif // defined(_MSC_VER)
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#endif // COROUTINE_HPP
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