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//
// coroutine.hpp
// ~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef COROUTINE_HPP
#define COROUTINE_HPP
class coroutine
{
public:
coroutine() : value_(0) {}
bool is_child() const { return value_ < 0; }
bool is_parent() const { return !is_child(); }
bool is_complete() const { return value_ == -1; }
private:
friend class coroutine_ref;
int value_;
};
class coroutine_ref
{
public:
coroutine_ref(coroutine& c) : value_(c.value_), modified_(false) {}
coroutine_ref(coroutine* c) : value_(c->value_), modified_(false) {}
~coroutine_ref() { if (!modified_) value_ = -1; }
operator int() const { return value_; }
int& operator=(int v) { modified_ = true; return value_ = v; }
private:
void operator=(const coroutine_ref&);
int& value_;
bool modified_;
};
#define CORO_REENTER(c) \
switch (coroutine_ref _coro_value = c) \
case -1: if (_coro_value) \
{ \
goto terminate_coroutine; \
terminate_coroutine: \
_coro_value = -1; \
goto bail_out_of_coroutine; \
bail_out_of_coroutine: \
break; \
} \
else case 0:
#define CORO_YIELD \
for (_coro_value = __LINE__;;) \
if (_coro_value == 0) \
{ \
case __LINE__: ; \
break; \
} \
else \
switch (_coro_value ? 0 : 1) \
for (;;) \
case -1: if (_coro_value) \
goto terminate_coroutine; \
else for (;;) \
case 1: if (_coro_value) \
goto bail_out_of_coroutine; \
else case 0:
#define CORO_FORK \
for (_coro_value = -__LINE__;; _coro_value = __LINE__) \
if (_coro_value == __LINE__) \
{ \
case -__LINE__: ; \
break; \
} \
else
#endif // COROUTINE_HPP
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