/*============================================================================= | |
Boost.Wave: A Standard compliant C++ preprocessor library | |
http://www.boost.org/ | |
Copyright (c) 2001-2011 Hartmut Kaiser. 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) | |
=============================================================================*/ | |
#if !defined(CPP_IFBLOCK_HPP_D4676B36_00C5_41F4_BC9F_9CBBAE3B8006_INCLUDED) | |
#define CPP_IFBLOCK_HPP_D4676B36_00C5_41F4_BC9F_9CBBAE3B8006_INCLUDED | |
#include <stack> | |
#include <boost/wave/wave_config.hpp> | |
// this must occur after all of the includes and before any code appears | |
#ifdef BOOST_HAS_ABI_HEADERS | |
#include BOOST_ABI_PREFIX | |
#endif | |
/////////////////////////////////////////////////////////////////////////////// | |
namespace boost { | |
namespace wave { | |
namespace util { | |
/////////////////////////////////////////////////////////////////////////////// | |
// the class if_blocks handles recursive conditional compilation contexts | |
class if_block | |
{ | |
public: | |
if_block() : | |
status(true), some_part_status(true), | |
enclosing_status(true), is_in_else(false) | |
{ | |
} | |
if_block(bool status_, bool enclosing_status_) : | |
status(status_), | |
some_part_status(status_), | |
enclosing_status(enclosing_status_), | |
is_in_else(false) | |
{ | |
} | |
void set_status(bool status_) | |
{ | |
status = status_; | |
if (status_) | |
some_part_status = true; | |
} | |
bool get_status() const { return status; } | |
bool get_some_part_status() const { return some_part_status; } | |
bool get_enclosing_status() const { return enclosing_status; } | |
bool get_in_else() const { return is_in_else; } | |
void set_in_else() { is_in_else = true; } | |
private: | |
bool status; // Current block is true | |
bool some_part_status; // One of the preceding or current #if/#elif was true | |
bool enclosing_status; // Enclosing #if block is true | |
bool is_in_else; // Inside the #else part | |
}; | |
/////////////////////////////////////////////////////////////////////////////// | |
// stack of conditional compilation contexts | |
class if_block_stack | |
: private std::stack<if_block> | |
{ | |
public: | |
typedef std::stack<if_block>::size_type size_type; | |
void enter_if_block(bool new_status) | |
{ | |
// If enclosing block is false, then this block is also false | |
bool enclosing_status = get_status(); | |
this->push (value_type (new_status && enclosing_status, enclosing_status)); | |
} | |
bool enter_elif_block(bool new_status) | |
{ | |
if (!is_inside_ifpart()) | |
return false; // #elif without matching #if | |
if (get_enclosing_status()) { | |
if (get_status()) { | |
// entered a (false) #elif block from a true block | |
this->top().set_status(false); | |
} | |
else if (new_status && !this->top().get_some_part_status()) { | |
// Entered true #elif block and no previous block was true | |
this->top().set_status(new_status); | |
} | |
} | |
return true; | |
} | |
bool enter_else_block() | |
{ | |
if (!is_inside_ifpart()) | |
return false; // #else without matching #if | |
if (get_enclosing_status()) { | |
if (!this->top().get_some_part_status()) { | |
// Entered (true) #else block and no previous block was true | |
this->top().set_status(true); | |
} | |
else if (get_status()) { | |
// Entered (false) #else block from true block | |
this->top().set_status(false); | |
} | |
// Set else flag | |
this->top().set_in_else(); | |
} | |
return true; | |
} | |
bool exit_if_block() | |
{ | |
if (0 == this->size()) | |
return false; // #endif without matching #if | |
this->pop(); | |
return true; | |
} | |
// return, whether the top (innermost) condition is true or false | |
bool get_status() const | |
{ | |
return 0 == this->size() || this->top().get_status(); | |
} | |
bool get_some_part_status() const | |
{ | |
return 0 == this->size() || this->top().get_some_part_status(); | |
} | |
bool get_enclosing_status() const | |
{ | |
return 0 == this->size() || this->top().get_enclosing_status(); | |
} | |
size_type get_if_block_depth() const { return this->size(); } | |
protected: | |
bool is_inside_ifpart() const | |
{ | |
return 0 != this->size() && !this->top().get_in_else(); | |
} | |
bool is_inside_elsepart() const | |
{ | |
return 0 != this->size() && this->top().get_in_else(); | |
} | |
}; | |
/////////////////////////////////////////////////////////////////////////////// | |
} // namespace util | |
} // namespace wave | |
} // namespace boost | |
// the suffix header occurs after all of the code | |
#ifdef BOOST_HAS_ABI_HEADERS | |
#include BOOST_ABI_SUFFIX | |
#endif | |
#endif // !defined(CPP_IFBLOCK_HPP_D4676B36_00C5_41F4_BC9F_9CBBAE3B8006_INCLUDED) |