libstdc++-v3/include/debug/helper_functions.h - gcc - Git at Google

 // Debugging support implementation -*- C++ -*-

 // Copyright (C) 2003-2021 Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
 // terms of the GNU General Public License as published by the
 // Free Software Foundation; either version 3, or (at your option)
 // any later version.

 // This library is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 // GNU General Public License for more details.

 // Under Section 7 of GPL version 3, you are granted additional
 // permissions described in the GCC Runtime Library Exception, version
 // 3.1, as published by the Free Software Foundation.

 // You should have received a copy of the GNU General Public License and
 // a copy of the GCC Runtime Library Exception along with this program;
 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 // <http://www.gnu.org/licenses/>.

 /** @file debug/helper_functions.h
  *  This file is a GNU debug extension to the Standard C++ Library.
  */

 #ifndef _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H
 #define _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H 1

 #include <bits/move.h>				// for __addressof
 #include <bits/stl_iterator_base_types.h>	// for iterator_traits,
 						// categories and _Iter_base
 #include <bits/cpp_type_traits.h>		// for __is_integer

 #include <bits/stl_pair.h>			// for pair

 namespace __gnu_debug
 {
   template<typename _Iterator, typename _Sequence, typename _Category>
     class _Safe_iterator;

 #if __cplusplus >= 201103L
   template<typename _Iterator, typename _Sequence>
     class _Safe_local_iterator;
 #endif

   /** The precision to which we can calculate the distance between
    *  two iterators.
    */
   enum _Distance_precision
     {
       __dp_none,		// Not even an iterator type
       __dp_equality,		//< Can compare iterator equality, only
       __dp_sign,		//< Can determine equality and ordering
       __dp_sign_max_size,	//< __dp_sign and gives max range size
       __dp_exact		//< Can determine distance precisely
     };

   template<typename _Iterator,
 	   typename = typename std::__is_integer<_Iterator>::__type>
     struct _Distance_traits
     {
     private:
       typedef
 	typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;

       template<typename _DiffType,
 	       typename = typename std::__is_void<_DiffType>::__type>
 	struct _DiffTraits
 	{ typedef _DiffType __type; };

       template<typename _DiffType>
 	struct _DiffTraits<_DiffType, std::__true_type>
 	{ typedef std::ptrdiff_t __type; };

       typedef typename _DiffTraits<_ItDiffType>::__type _DiffType;

     public:
       typedef std::pair<_DiffType, _Distance_precision> __type;
     };

   template<typename _Integral>
     struct _Distance_traits<_Integral, std::__true_type>
     { typedef std::pair<std::ptrdiff_t, _Distance_precision> __type; };

   /** Determine the distance between two iterators with some known
    *	precision.
   */
   template<typename _Iterator>
     _GLIBCXX_CONSTEXPR
     inline typename _Distance_traits<_Iterator>::__type
     __get_distance(_Iterator __lhs, _Iterator __rhs,
 		   std::random_access_iterator_tag)
     { return std::make_pair(__rhs - __lhs, __dp_exact); }

   template<typename _Iterator>
     _GLIBCXX14_CONSTEXPR
     inline typename _Distance_traits<_Iterator>::__type
     __get_distance(_Iterator __lhs, _Iterator __rhs,
 		   std::input_iterator_tag)
     {
       if (__lhs == __rhs)
 	return std::make_pair(0, __dp_exact);

       return std::make_pair(1, __dp_equality);
     }

   template<typename _Iterator>
     _GLIBCXX_CONSTEXPR
     inline typename _Distance_traits<_Iterator>::__type
     __get_distance(_Iterator __lhs, _Iterator __rhs)
     { return __get_distance(__lhs, __rhs, std::__iterator_category(__lhs)); }

   // An arbitrary iterator pointer is not singular.
   inline bool
   __check_singular_aux(const void*) { return false; }

   // We may have an iterator that derives from _Safe_iterator_base but isn't
   // a _Safe_iterator.
   template<typename _Iterator>
     _GLIBCXX_CONSTEXPR
     inline bool
     __check_singular(_Iterator const& __x)
     {
       return
 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
 	__builtin_is_constant_evaluated() ? false :
 #endif
 	__check_singular_aux(std::__addressof(__x));
     }

   /** Non-NULL pointers are nonsingular. */
   template<typename _Tp>
     _GLIBCXX_CONSTEXPR
     inline bool
     __check_singular(_Tp* const& __ptr)
     {
       return
 #ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
 	__builtin_is_constant_evaluated() ? false :
 #endif
 	__ptr == 0;
     }

   /** We say that integral types for a valid range, and defer to other
    *  routines to realize what to do with integral types instead of
    *  iterators.
   */
   template<typename _Integral>
     _GLIBCXX_CONSTEXPR
     inline bool
     __valid_range_aux(_Integral, _Integral, std::__true_type)
     { return true; }

   template<typename _Integral>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __valid_range_aux(_Integral, _Integral,
 		      typename _Distance_traits<_Integral>::__type& __dist,
 		      std::__true_type)
     {
       __dist = std::make_pair(0, __dp_none);
       return true;
     }

   template<typename _InputIterator>
     _GLIBCXX_CONSTEXPR
     inline bool
     __valid_range_aux(_InputIterator __first, _InputIterator __last,
 		      std::input_iterator_tag)
     {
       return __first == __last
 	|| (!__check_singular(__first) && !__check_singular(__last));
     }

   template<typename _InputIterator>
     _GLIBCXX_CONSTEXPR
     inline bool
     __valid_range_aux(_InputIterator __first, _InputIterator __last,
 		      std::random_access_iterator_tag)
     {
       return
 	__valid_range_aux(__first, __last, std::input_iterator_tag())
 	&& __first <= __last;
     }

   /** We have iterators, so figure out what kind of iterators they are
    *  to see if we can check the range ahead of time.
   */
   template<typename _InputIterator>
     _GLIBCXX_CONSTEXPR
     inline bool
     __valid_range_aux(_InputIterator __first, _InputIterator __last,
 		      std::__false_type)
     {
       return __valid_range_aux(__first, __last,
 			       std::__iterator_category(__first));
     }

   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __valid_range_aux(_InputIterator __first, _InputIterator __last,
 		      typename _Distance_traits<_InputIterator>::__type& __dist,
 		      std::__false_type)
     {
       if (!__valid_range_aux(__first, __last, std::input_iterator_tag()))
 	return false;

       __dist = __get_distance(__first, __last);
       switch (__dist.second)
 	{
 	case __dp_none:
 	  break;
 	case __dp_equality:
 	  if (__dist.first == 0)
 	    return true;
 	  break;
 	case __dp_sign:
 	case __dp_sign_max_size:
 	case __dp_exact:
 	  return __dist.first >= 0;
 	}

       // Can't tell so assume it is fine.
       return true;
     }

   /** Don't know what these iterators are, or if they are even
    *  iterators (we may get an integral type for InputIterator), so
    *  see if they are integral and pass them on to the next phase
    *  otherwise.
   */
   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __valid_range(_InputIterator __first, _InputIterator __last,
 		  typename _Distance_traits<_InputIterator>::__type& __dist)
     {
       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
       return __valid_range_aux(__first, __last, __dist, _Integral());
     }

   template<typename _Iterator, typename _Sequence, typename _Category>
     bool
     __valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 		  const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 		  typename _Distance_traits<_Iterator>::__type&);

 #if __cplusplus >= 201103L
   template<typename _Iterator,typename _Sequence>
     bool
     __valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
 		  const _Safe_local_iterator<_Iterator, _Sequence>&,
 		  typename _Distance_traits<_Iterator>::__type&);
 #endif

   template<typename _InputIterator>
     _GLIBCXX14_CONSTEXPR
     inline bool
     __valid_range(_InputIterator __first, _InputIterator __last)
     {
       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
       return __valid_range_aux(__first, __last, _Integral());
     }

   template<typename _Iterator, typename _Sequence, typename _Category>
     bool
     __valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 		  const _Safe_iterator<_Iterator, _Sequence, _Category>&);

 #if __cplusplus >= 201103L
   template<typename _Iterator, typename _Sequence>
     bool
     __valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
 		  const _Safe_local_iterator<_Iterator, _Sequence>&);
 #endif

   // Fallback method, always ok.
   template<typename _InputIterator, typename _Size>
     _GLIBCXX_CONSTEXPR
     inline bool
     __can_advance(_InputIterator, _Size)
     { return true; }

   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _Size>
     bool
     __can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 		  _Size);

   template<typename _InputIterator, typename _Diff>
     _GLIBCXX_CONSTEXPR
     inline bool
     __can_advance(_InputIterator, const std::pair<_Diff, _Distance_precision>&, int)
     { return true; }

   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _Diff>
     bool
     __can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 		  const std::pair<_Diff, _Distance_precision>&, int);

   /** Helper function to extract base iterator of random access safe iterator
    *  in order to reduce performance impact of debug mode.  Limited to random
    *  access iterator because it is the only category for which it is possible
    *  to check for correct iterators order in the __valid_range function
    *  thanks to the < operator.
    */
   template<typename _Iterator>
     _GLIBCXX_CONSTEXPR
     inline _Iterator
     __base(_Iterator __it)
     { return __it; }

 #if __cplusplus < 201103L
   template<typename _Iterator>
     struct _Unsafe_type
     { typedef _Iterator _Type; };
 #endif

   /* Remove debug mode safe iterator layer, if any. */
   template<typename _Iterator>
     inline _Iterator
     __unsafe(_Iterator __it)
     { return __it; }
 }

 #endif
	// Debugging support implementation -- C++ --

	// Copyright (C) 2003-2021 Free Software Foundation, Inc.
	//
	// This file is part of the GNU ISO C++ Library. This library is free
	// software; you can redistribute it and/or modify it under the
	// terms of the GNU General Public License as published by the
	// Free Software Foundation; either version 3, or (at your option)
	// any later version.

	// This library is distributed in the hope that it will be useful,
	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	// GNU General Public License for more details.

	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.

	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
	// <http://www.gnu.org/licenses/>.

	/** @file debug/helper_functions.h
	* This file is a GNU debug extension to the Standard C++ Library.
	*/

	#ifndef _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H
	#define _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H 1

	#include <bits/move.h> // for __addressof
	#include <bits/stl_iterator_base_types.h> // for iterator_traits,
	// categories and _Iter_base
	#include <bits/cpp_type_traits.h> // for __is_integer

	#include <bits/stl_pair.h> // for pair

	namespace __gnu_debug
	{
	template<typename _Iterator, typename _Sequence, typename _Category>
	class _Safe_iterator;

	#if __cplusplus >= 201103L
	template<typename _Iterator, typename _Sequence>
	class _Safe_local_iterator;
	#endif

	/** The precision to which we can calculate the distance between
	* two iterators.
	*/
	enum _Distance_precision
	{
	__dp_none, // Not even an iterator type
	__dp_equality, //< Can compare iterator equality, only
	__dp_sign, //< Can determine equality and ordering
	__dp_sign_max_size, //< __dp_sign and gives max range size
	__dp_exact //< Can determine distance precisely
	};

	template<typename _Iterator,
	typename = typename std::__is_integer<_Iterator>::__type>
	struct _Distance_traits
	{
	private:
	typedef
	typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;

	template<typename _DiffType,
	typename = typename std::__is_void<_DiffType>::__type>
	struct _DiffTraits
	{ typedef _DiffType __type; };

	template<typename _DiffType>
	struct _DiffTraits<_DiffType, std::__true_type>
	{ typedef std::ptrdiff_t __type; };

	typedef typename _DiffTraits<_ItDiffType>::__type _DiffType;

	public:
	typedef std::pair<_DiffType, _Distance_precision> __type;
	};

	template<typename _Integral>
	struct _Distance_traits<_Integral, std::__true_type>
	{ typedef std::pair<std::ptrdiff_t, _Distance_precision> __type; };

	/** Determine the distance between two iterators with some known
	* precision.
	*/
	template<typename _Iterator>
	_GLIBCXX_CONSTEXPR
	inline typename _Distance_traits<_Iterator>::__type
	__get_distance(_Iterator __lhs, _Iterator __rhs,
	std::random_access_iterator_tag)
	{ return std::make_pair(__rhs - __lhs, __dp_exact); }

	template<typename _Iterator>
	_GLIBCXX14_CONSTEXPR
	inline typename _Distance_traits<_Iterator>::__type
	__get_distance(_Iterator __lhs, _Iterator __rhs,
	std::input_iterator_tag)
	{
	if (__lhs == __rhs)
	return std::make_pair(0, __dp_exact);

	return std::make_pair(1, __dp_equality);
	}

	template<typename _Iterator>
	_GLIBCXX_CONSTEXPR
	inline typename _Distance_traits<_Iterator>::__type
	__get_distance(_Iterator __lhs, _Iterator __rhs)
	{ return __get_distance(__lhs, __rhs, std::__iterator_category(__lhs)); }

	// An arbitrary iterator pointer is not singular.
	inline bool
	__check_singular_aux(const void*) { return false; }

	// We may have an iterator that derives from _Safe_iterator_base but isn't
	// a _Safe_iterator.
	template<typename _Iterator>
	_GLIBCXX_CONSTEXPR
	inline bool
	__check_singular(_Iterator const& __x)
	{
	return
	#ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
	__builtin_is_constant_evaluated() ? false :
	#endif
	__check_singular_aux(std::__addressof(__x));
	}

	/** Non-NULL pointers are nonsingular. */
	template<typename _Tp>
	_GLIBCXX_CONSTEXPR
	inline bool
	__check_singular(_Tp* const& __ptr)
	{
	return
	#ifdef _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED
	__builtin_is_constant_evaluated() ? false :
	#endif
	__ptr == 0;
	}

	/** We say that integral types for a valid range, and defer to other
	* routines to realize what to do with integral types instead of
	* iterators.
	*/
	template<typename _Integral>
	_GLIBCXX_CONSTEXPR
	inline bool
	__valid_range_aux(_Integral, _Integral, std::__true_type)
	{ return true; }

	template<typename _Integral>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__valid_range_aux(_Integral, _Integral,
	typename _Distance_traits<_Integral>::__type& __dist,
	std::__true_type)
	{
	__dist = std::make_pair(0, __dp_none);
	return true;
	}

	template<typename _InputIterator>
	_GLIBCXX_CONSTEXPR
	inline bool
	__valid_range_aux(_InputIterator __first, _InputIterator __last,
	std::input_iterator_tag)
	{
	return __first == __last
	\|\| (!__check_singular(__first) && !__check_singular(__last));
	}

	template<typename _InputIterator>
	_GLIBCXX_CONSTEXPR
	inline bool
	__valid_range_aux(_InputIterator __first, _InputIterator __last,
	std::random_access_iterator_tag)
	{
	return
	__valid_range_aux(__first, __last, std::input_iterator_tag())
	&& __first <= __last;
	}

	/** We have iterators, so figure out what kind of iterators they are
	* to see if we can check the range ahead of time.
	*/
	template<typename _InputIterator>
	_GLIBCXX_CONSTEXPR
	inline bool
	__valid_range_aux(_InputIterator __first, _InputIterator __last,
	std::__false_type)
	{
	return __valid_range_aux(__first, __last,
	std::__iterator_category(__first));
	}

	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__valid_range_aux(_InputIterator __first, _InputIterator __last,
	typename _Distance_traits<_InputIterator>::__type& __dist,
	std::__false_type)
	{
	if (!__valid_range_aux(__first, __last, std::input_iterator_tag()))
	return false;

	__dist = __get_distance(__first, __last);
	switch (__dist.second)
	{
	case __dp_none:
	break;
	case __dp_equality:
	if (__dist.first == 0)
	return true;
	break;
	case __dp_sign:
	case __dp_sign_max_size:
	case __dp_exact:
	return __dist.first >= 0;
	}

	// Can't tell so assume it is fine.
	return true;
	}

	/** Don't know what these iterators are, or if they are even
	* iterators (we may get an integral type for InputIterator), so
	* see if they are integral and pass them on to the next phase
	* otherwise.
	*/
	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__valid_range(_InputIterator __first, _InputIterator __last,
	typename _Distance_traits<_InputIterator>::__type& __dist)
	{
	typedef typename std::__is_integer<_InputIterator>::__type _Integral;
	return __valid_range_aux(__first, __last, __dist, _Integral());
	}

	template<typename _Iterator, typename _Sequence, typename _Category>
	bool
	__valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	typename _Distance_traits<_Iterator>::__type&);

	#if __cplusplus >= 201103L
	template<typename _Iterator,typename _Sequence>
	bool
	__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
	const _Safe_local_iterator<_Iterator, _Sequence>&,
	typename _Distance_traits<_Iterator>::__type&);
	#endif

	template<typename _InputIterator>
	_GLIBCXX14_CONSTEXPR
	inline bool
	__valid_range(_InputIterator __first, _InputIterator __last)
	{
	typedef typename std::__is_integer<_InputIterator>::__type _Integral;
	return __valid_range_aux(__first, __last, _Integral());
	}

	template<typename _Iterator, typename _Sequence, typename _Category>
	bool
	__valid_range(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	const _Safe_iterator<_Iterator, _Sequence, _Category>&);

	#if __cplusplus >= 201103L
	template<typename _Iterator, typename _Sequence>
	bool
	__valid_range(const _Safe_local_iterator<_Iterator, _Sequence>&,
	const _Safe_local_iterator<_Iterator, _Sequence>&);
	#endif

	// Fallback method, always ok.
	template<typename _InputIterator, typename _Size>
	_GLIBCXX_CONSTEXPR
	inline bool
	__can_advance(_InputIterator, _Size)
	{ return true; }

	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _Size>
	bool
	__can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	_Size);

	template<typename _InputIterator, typename _Diff>
	_GLIBCXX_CONSTEXPR
	inline bool
	__can_advance(_InputIterator, const std::pair<_Diff, _Distance_precision>&, int)
	{ return true; }

	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _Diff>
	bool
	__can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	const std::pair<_Diff, _Distance_precision>&, int);

	/** Helper function to extract base iterator of random access safe iterator
	* in order to reduce performance impact of debug mode. Limited to random
	* access iterator because it is the only category for which it is possible
	* to check for correct iterators order in the __valid_range function
	* thanks to the < operator.
	*/
	template<typename _Iterator>
	_GLIBCXX_CONSTEXPR
	inline _Iterator
	__base(_Iterator __it)
	{ return __it; }

	#if __cplusplus < 201103L
	template<typename _Iterator>
	struct _Unsafe_type
	{ typedef _Iterator _Type; };
	#endif

	/* Remove debug mode safe iterator layer, if any. */
	template<typename _Iterator>
	inline _Iterator
	__unsafe(_Iterator __it)
	{ return __it; }
	}

	#endif