lyx_mirror/boost/boost/iterator_adaptors.hpp
Lars Gullik Bjønnes 9e27f631a7 update from Boost CVS
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@4918 a592a061-630c-0410-9148-cb99ea01b6c8
2002-08-09 08:51:51 +00:00

1431 lines
52 KiB
C++

// (C) Copyright David Abrahams 2000. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
//
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify,
// sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.
//
// Revision History:
// 01 Feb 2002 Jeremy Siek
// Added more comments in default_iterator_policies.
// 08 Jan 2001 David Abrahams
// Moved concept checks into a separate class, which makes MSVC
// better at dealing with them.
// 07 Jan 2001 David Abrahams
// Choose proxy for operator->() only if the reference type is not a reference.
// Updated workarounds for __MWERKS__ == 0x2406
// 20 Dec 2001 David Abrahams
// Adjusted is_convertible workarounds for __MWERKS__ == 0x2406
// 03 Nov 2001 Jeremy Siek
// Changed the named template parameter interface and internal.
// 04 Oct 2001 Jeremy Siek
// Changed projection_iterator to not rely on the default reference,
// working around a limitation of detail::iterator_traits.
// 04 Oct 2001 David Abrahams
// Applied indirect_iterator patch from George A. Heintzelman <georgeh@aya.yale.edu>
// Changed name of "bind" to "select" to avoid problems with MSVC.
// 26 Sep 2001 David Abrahams
// Added borland bug fix
// 08 Mar 2001 Jeremy Siek
// Added support for optional named template parameters.
// 19 Feb 2001 David Abrahams
// Rolled back reverse_iterator_pair_generator again, as it doesn't
// save typing on a conforming compiler.
// 18 Feb 2001 David Abrahams
// Reinstated reverse_iterator_pair_generator
// 16 Feb 2001 David Abrahams
// Add an implicit conversion operator to operator_arrow_proxy
// as CW and BCC workarounds.
// 11 Feb 2001 David Abrahams
// Switch to use of BOOST_STATIC_CONSTANT where possible
// 11 Feb 2001 Jeremy Siek
// Removed workaround for older MIPSpro compiler. The workaround
// was preventing the proper functionality of the underlying
// iterator being carried forward into the iterator adaptor.
// Also added is_bidirectional enum to avoid EDG compiler error.
// 11 Feb 2001 David Abrahams
// Borland fixes up the wazoo. It finally works!
// 10 Feb 2001 David Abrahams
// Removed traits argument from iterator_adaptor<> and switched to
// explicit trait specification for maximum ease-of-use.
// Added comments to detail::iterator_defaults<>
// Began using detail::iterator_defaults<> unconditionally for code clarity
// Changed uses of `Iterator' to `Base' where non-iterators can be used.
//
// 10 Feb 2001 David Abrahams
// Rolled in supposed Borland fixes from John Maddock, but not seeing any
// improvement yet
// Changed argument order to indirect_ generator, for convenience in the
// case of input iterators (where Reference must be a value type).
// Removed derivation of filter_iterator_policies from
// default_iterator_policies, since the iterator category is likely to be
// reduced (we don't want to allow illegal operations like decrement).
// Support for a simpler filter iterator interface.
//
// 09 Feb 2001 David Abrahams
// Improved interface to indirect_ and reverse_ iterators
// Rolled back Jeremy's new constructor for now; it was causing
// problems with counting_iterator_test
// Attempted fix for Borland
//
// 09 Feb 2001 Jeremy Siek
// Added iterator constructor to allow const adaptor
// from non-const adaptee.
// Changed make_xxx to pass iterators by-value to
// get arrays converted to pointers.
// Removed InnerIterator template parameter from
// indirect_iterator_generator.
// Rearranged parameters for make_filter_iterator
//
// 07 Feb 2001 Jeremy Siek
// Removed some const iterator adaptor generators.
// Added make_xxx_iterator() helper functions for remaining
// iterator adaptors.
// Removed some traits template parameters where they
// where no longer needed thanks to detail::iterator_traits.
// Moved some of the compile-time logic into enums for
// EDG compatibility.
//
// 07 Feb 2001 David Abrahams
// Removed iterator_adaptor_pair_generator and
// reverse_iterator_pair_generator (more such culling to come)
// Improved comments
// Changed all uses of std::iterator_traits as default arguments
// to boost::detail::iterator_traits for improved utility in
// non-generic contexts
// Fixed naming convention of non-template parameter names
//
// 06 Feb 2001 David Abrahams
// Produce operator-> proxy objects for InputIterators
// Added static assertions to do some basic concept checks
// Renamed single-type generators -> xxx_generator
// Renamed const/nonconst iterator generators -> xxx_pair_generator
// Added make_transform_iterator(iter, function)
// The existence of boost::detail::iterator_traits allowed many
// template arguments to be defaulted. Some arguments had to be
// moved to accomplish it.
//
// 04 Feb 2001 MWERKS bug workaround, concept checking for proper
// reference types (David Abrahams)
#ifndef BOOST_ITERATOR_ADAPTOR_DWA053000_HPP_
# define BOOST_ITERATOR_ADAPTOR_DWA053000_HPP_
# include <boost/iterator.hpp>
# include <boost/utility.hpp>
# include <boost/compressed_pair.hpp>
# include <boost/concept_check.hpp>
# include <boost/type.hpp>
# include <boost/static_assert.hpp>
# include <boost/type_traits.hpp>
# include <boost/detail/iterator.hpp>
# include <boost/detail/select_type.hpp>
// I was having some problems with VC6. I couldn't tell whether our hack for
// stock GCC was causing problems so I needed an easy way to turn it on and
// off. Now we can test the hack with various compilers and still have an
// "out" if it doesn't work. -dwa 7/31/00
# if __GNUC__ == 2 && __GNUC_MINOR__ <= 96 && !defined(__STL_USE_NAMESPACES)
# define BOOST_RELOPS_AMBIGUITY_BUG 1
# endif
namespace boost {
//============================================================================
// Concept checking classes that express the requirements for iterator
// policies and adapted types. These classes are mostly for
// documentation purposes, and are not used in this header file. They
// merely provide a more succinct statement of what is expected of the
// iterator policies.
template <class Policies, class Adapted, class Traits>
struct TrivialIteratorPoliciesConcept
{
typedef typename Traits::reference reference;
void constraints() {
function_requires< AssignableConcept<Policies> >();
function_requires< DefaultConstructibleConcept<Policies> >();
function_requires< AssignableConcept<Adapted> >();
function_requires< DefaultConstructibleConcept<Adapted> >();
const_constraints();
}
void const_constraints() const {
reference r = p.dereference(x);
b = p.equal(x, x);
ignore_unused_variable_warning(r);
}
Policies p;
Adapted x;
mutable bool b;
};
// Add InputIteratorPoliciesConcept?
template <class Policies, class Adapted, class Traits>
struct ForwardIteratorPoliciesConcept
{
typedef typename Traits::iterator_category iterator_category;
void constraints() {
function_requires<
TrivialIteratorPoliciesConcept<Policies, Adapted, Traits>
>();
p.increment(x);
std::forward_iterator_tag t = iterator_category();
ignore_unused_variable_warning(t);
}
Policies p;
Adapted x;
iterator_category category;
};
template <class Policies, class Adapted, class Traits>
struct BidirectionalIteratorPoliciesConcept
{
typedef typename Traits::iterator_category iterator_category;
void constraints() {
function_requires<
ForwardIteratorPoliciesConcept<Policies, Adapted, Traits>
>();
p.decrement(x);
std::bidirectional_iterator_tag t = iterator_category();
ignore_unused_variable_warning(t);
}
Policies p;
Adapted x;
};
template <class Policies, class Adapted, class Traits>
struct RandomAccessIteratorPoliciesConcept
{
typedef typename Traits::difference_type DifferenceType;
typedef typename Traits::iterator_category iterator_category;
void constraints() {
function_requires<
BidirectionalIteratorPoliciesConcept<Policies, Adapted, Traits>
>();
p.advance(x, n);
std::random_access_iterator_tag t = iterator_category();
const_constraints();
ignore_unused_variable_warning(t);
}
void const_constraints() const {
n = p.distance(x, x);
}
Policies p;
Adapted x;
mutable DifferenceType n;
mutable bool b;
};
//============================================================================
// Default policies for iterator adaptors. You can use this as a base
// class if you want to customize particular policies.
struct default_iterator_policies
{
// Some of the member functions were defined static, but Borland
// got confused and thought they were non-const. Also, Sun C++
// does not like static function templates.
//
// The reason some members were defined static is because there is
// not state (data members) needed by those members of the
// default_iterator_policies class. If your policies class member
// functions need to access state stored in the policies object,
// then the member functions should not be static (they can't be).
template <class Base>
void initialize(Base&)
{ }
template <class IteratorAdaptor>
typename IteratorAdaptor::reference dereference(const IteratorAdaptor& x) const
{ return *x.base(); }
template <class IteratorAdaptor>
void increment(IteratorAdaptor& x)
{ ++x.base(); }
template <class IteratorAdaptor>
void decrement(IteratorAdaptor& x)
{ --x.base(); }
template <class IteratorAdaptor, class DifferenceType>
void advance(IteratorAdaptor& x, DifferenceType n)
{ x.base() += n; }
template <class IteratorAdaptor1, class IteratorAdaptor2>
typename IteratorAdaptor1::difference_type
distance(const IteratorAdaptor1& x, const IteratorAdaptor2& y) const
{ return y.base() - x.base(); }
template <class IteratorAdaptor1, class IteratorAdaptor2>
bool equal(const IteratorAdaptor1& x, const IteratorAdaptor2& y) const
{ return x.base() == y.base(); }
};
// putting the comparisons in a base class avoids the g++
// ambiguous overload bug due to the relops operators
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
template <class Derived, class Base>
struct iterator_comparisons : Base { };
template <class D1, class D2, class Base1, class Base2>
inline bool operator==(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().equal(x, y);
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator!=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return !x.policies().equal(x, y);
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator<(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().distance(y, x) < 0;
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator>(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().distance(y, x) > 0;
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator>=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().distance(y, x) >= 0;
}
template <class D1, class D2, class Base1, class Base2>
inline bool operator<=(const iterator_comparisons<D1,Base1>& xb,
const iterator_comparisons<D2,Base2>& yb)
{
const D1& x = static_cast<const D1&>(xb);
const D2& y = static_cast<const D2&>(yb);
return x.policies().distance(y, x) <= 0;
}
#endif
namespace detail {
// operator->() needs special support for input iterators to strictly meet the
// standard's requirements. If *i is not a reference type, we must still
// produce a (constant) lvalue to which a pointer can be formed. We do that by
// returning an instantiation of this special proxy class template.
template <class T>
struct operator_arrow_proxy
{
operator_arrow_proxy(const T& x) : m_value(x) {}
const T* operator->() const { return &m_value; }
// This function is needed for MWCW and BCC, which won't call operator->
// again automatically per 13.3.1.2 para 8
operator const T*() const { return &m_value; }
T m_value;
};
template <class Iter>
inline operator_arrow_proxy<typename Iter::value_type>
operator_arrow(const Iter& i, std::input_iterator_tag) {
typedef typename Iter::value_type value_t; // VC++ needs this typedef
return operator_arrow_proxy<value_t>(*i);
}
template <class Iter>
inline typename Iter::pointer
operator_arrow(const Iter& i, std::forward_iterator_tag) {
return &(*i);
}
template <class Value, class Reference, class Pointer>
struct operator_arrow_result_generator
{
typedef operator_arrow_proxy<Value> proxy;
// Borland chokes unless it's an actual enum (!)
enum { use_proxy = !boost::is_reference<Reference>::value };
typedef typename boost::detail::if_true<(use_proxy)>::template
then<
proxy,
// else
Pointer
>::type type;
};
# if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) || defined(BOOST_NO_STD_ITERATOR_TRAITS)
// Select default pointer and reference types for adapted non-pointer
// iterators based on the iterator and the value_type. Poor man's partial
// specialization is in use here.
template <bool is_pointer>
struct iterator_defaults_select
{
template <class Iterator,class Value>
struct traits
{
// The assumption is that iterator_traits can deduce these types
// properly as long as the iterator is not a pointer.
typedef typename boost::detail::iterator_traits<Iterator>::pointer pointer;
typedef typename boost::detail::iterator_traits<Iterator>::reference reference;
};
};
// Select default pointer and reference types for adapted pointer iterators
// given a (possibly-const) value_type.
template <>
struct iterator_defaults_select<true>
{
template <class Iterator,class Value>
struct traits
{
typedef Value* pointer;
typedef Value& reference;
};
};
// Consolidate selection of the default pointer and reference type
template <class Iterator,class Value>
struct iterator_defaults
{
BOOST_STATIC_CONSTANT(bool, is_ptr = boost::is_pointer<Iterator>::value);
typedef typename iterator_defaults_select<is_ptr>::template traits<Iterator,Value> traits;
typedef typename traits::pointer pointer;
typedef typename traits::reference reference;
};
# else
template <class Iterator,class Value>
struct iterator_defaults : iterator_traits<Iterator>
{
// Trying to factor the common is_same expression into an enum or a
// static bool constant confused Borland.
typedef typename if_true<(
::boost::is_same<Value,typename iterator_traits<Iterator>::value_type>::value
)>::template then<
typename iterator_traits<Iterator>::pointer,
Value*
>::type pointer;
typedef typename if_true<(
::boost::is_same<Value,typename iterator_traits<Iterator>::value_type>::value
)>::template then<
typename iterator_traits<Iterator>::reference,
Value&
>::type reference;
};
# endif
//===========================================================================
// Specify the defaults for iterator_adaptor's template parameters
struct default_argument { };
// This class template is a workaround for MSVC.
struct dummy_default_gen {
template <class Base, class Traits>
struct select { typedef default_argument type; };
};
// This class template is a workaround for MSVC.
template <class Gen> struct default_generator {
typedef dummy_default_gen type;
};
struct default_value_type {
template <class Base, class Traits>
struct select {
typedef typename boost::detail::iterator_traits<Base>::value_type type;
};
};
template <> struct default_generator<default_value_type>
{ typedef default_value_type type; }; // VC++ workaround
struct default_difference_type {
template <class Base, class Traits>
struct select {
typedef typename boost::detail::iterator_traits<Base>::difference_type type;
};
};
template <> struct default_generator<default_difference_type>
{ typedef default_difference_type type; }; // VC++ workaround
struct default_iterator_category {
template <class Base, class Traits>
struct select {
typedef typename boost::detail::iterator_traits<Base>::iterator_category type;
};
};
template <> struct default_generator<default_iterator_category>
{ typedef default_iterator_category type; }; // VC++ workaround
struct default_pointer {
template <class Base, class Traits>
struct select {
typedef typename Traits::value_type Value;
typedef typename boost::detail::iterator_defaults<Base,Value>::pointer
type;
};
};
template <> struct default_generator<default_pointer>
{ typedef default_pointer type; }; // VC++ workaround
struct default_reference {
template <class Base, class Traits>
struct select {
typedef typename Traits::value_type Value;
typedef typename boost::detail::iterator_defaults<Base,Value>::reference
type;
};
};
template <> struct default_generator<default_reference>
{ typedef default_reference type; }; // VC++ workaround
} // namespace detail
//===========================================================================
// Support for named template parameters
struct named_template_param_base { };
namespace detail {
struct value_type_tag { };
struct reference_tag { };
struct pointer_tag { };
struct difference_type_tag { };
struct iterator_category_tag { };
// avoid using std::pair because A or B might be a reference type, and g++
// complains about forming references to references inside std::pair
template <class A, class B>
struct cons_type {
typedef A first_type;
typedef B second_type;
};
} // namespace detail
template <class Value> struct value_type_is : public named_template_param_base
{
typedef detail::cons_type<detail::value_type_tag, Value> type;
};
template <class Reference> struct reference_is : public named_template_param_base
{
typedef detail::cons_type<detail::reference_tag, Reference> type;
};
template <class Pointer> struct pointer_is : public named_template_param_base
{
typedef detail::cons_type<detail::pointer_tag, Pointer> type;
};
template <class Difference> struct difference_type_is
: public named_template_param_base
{
typedef detail::cons_type<detail::difference_type_tag, Difference> type;
};
template <class IteratorCategory> struct iterator_category_is
: public named_template_param_base
{
typedef detail::cons_type<detail::iterator_category_tag, IteratorCategory> type;
};
namespace detail {
struct end_of_list { };
// Given an associative list, find the value with the matching key.
// An associative list is a list of key-value pairs. The list is
// built out of cons_type's and is terminated by end_of_list.
# if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) || defined(__BORLANDC__)
template <class AssocList, class Key>
struct find_param;
struct find_param_continue {
template <class AssocList, class Key2> struct select {
typedef typename AssocList::first_type Head;
typedef typename Head::first_type Key1;
typedef typename Head::second_type Value;
typedef typename if_true<(is_same<Key1, Key2>::value)>::template
then<Value,
typename find_param<typename AssocList::second_type, Key2>::type
>::type type;
};
};
struct find_param_end {
template <class AssocList, class Key>
struct select { typedef detail::default_argument type; };
};
template <class AssocList> struct find_param_helper1
{ typedef find_param_continue type; };
template <> struct find_param_helper1<end_of_list>
{ typedef find_param_end type; };
template <class AssocList, class Key>
struct find_param {
typedef typename find_param_helper1<AssocList>::type select1;
typedef typename select1::template select<AssocList, Key>::type type;
};
# else
template <class AssocList, class Key> struct find_param;
template <class Key>
struct find_param<end_of_list, Key> { typedef default_argument type; };
// Found a matching Key, return the associated Value
template <class Key, class Value, class Rest>
struct find_param<detail::cons_type< detail::cons_type<Key, Value>, Rest>, Key> {
typedef Value type;
};
// Non-matching keys, continue the search
template <class Key1, class Value, class Rest, class Key2>
struct find_param<detail::cons_type< detail::cons_type<Key1, Value>, Rest>, Key2> {
typedef typename find_param<Rest, Key2>::type type;
};
# endif
struct make_named_arg {
template <class Key, class Value>
struct select { typedef typename Value::type type; };
};
struct make_key_value {
template <class Key, class Value>
struct select { typedef detail::cons_type<Key, Value> type; };
};
template <class Value>
struct is_named_parameter
{
enum { value = is_convertible< typename add_reference< Value >::type, add_reference< named_template_param_base >::type >::value };
};
# if defined(__MWERKS__) && __MWERKS__ <= 0x2406 // workaround for broken is_convertible implementation
template <class T> struct is_named_parameter<value_type_is<T> > { enum { value = true }; };
template <class T> struct is_named_parameter<reference_is<T> > { enum { value = true }; };
template <class T> struct is_named_parameter<pointer_is<T> > { enum { value = true }; };
template <class T> struct is_named_parameter<difference_type_is<T> > { enum { value = true }; };
template <class T> struct is_named_parameter<iterator_category_is<T> > { enum { value = true }; };
# endif
template <class Key, class Value>
struct make_arg {
# ifdef __BORLANDC__
// Borland C++ doesn't like the extra indirection of is_named_parameter
typedef typename
if_true<(is_convertible<Value,named_template_param_base>::value)>::
template then<make_named_arg, make_key_value>::type Make;
# else
enum { is_named = is_named_parameter<Value>::value };
typedef typename if_true<(is_named)>::template
then<make_named_arg, make_key_value>::type Make;
# endif
typedef typename Make::template select<Key, Value>::type type;
};
// Mechanism for resolving the default argument for a template parameter.
template <class T> struct is_default { typedef type_traits::no_type type; };
template <> struct is_default<default_argument>
{ typedef type_traits::yes_type type; };
struct choose_default {
template <class Arg, class DefaultGen, class Base, class Traits>
struct select {
typedef typename default_generator<DefaultGen>::type Gen;
typedef typename Gen::template select<Base,Traits>::type type;
};
};
struct choose_arg {
template <class Arg, class DefaultGen, class Base, class Traits>
struct select {
typedef Arg type;
};
};
template <class UseDefault>
struct choose_arg_or_default { typedef choose_arg type; };
template <> struct choose_arg_or_default<type_traits::yes_type> {
typedef choose_default type;
};
template <class Arg, class DefaultGen, class Base, class Traits>
class resolve_default {
typedef typename choose_arg_or_default<typename is_default<Arg>::type>::type
Selector;
public:
typedef typename Selector
::template select<Arg, DefaultGen, Base, Traits>::type type;
};
template <class Base, class Value, class Reference, class Pointer,
class Category, class Distance>
class iterator_adaptor_traits_gen
{
// Form an associative list out of the template parameters
// If the argument is a normal parameter (not named) then make_arg
// creates a key-value pair. If the argument is a named parameter,
// then make_arg extracts the key-value pair defined inside the
// named parameter.
typedef detail::cons_type< typename make_arg<value_type_tag, Value>::type,
detail::cons_type<typename make_arg<reference_tag, Reference>::type,
detail::cons_type<typename make_arg<pointer_tag, Pointer>::type,
detail::cons_type<typename make_arg<iterator_category_tag, Category>::type,
detail::cons_type<typename make_arg<difference_type_tag, Distance>::type,
end_of_list> > > > > ArgList;
// Search the list for particular parameters
typedef typename find_param<ArgList, value_type_tag>::type Val;
typedef typename find_param<ArgList, difference_type_tag>::type Diff;
typedef typename find_param<ArgList, iterator_category_tag>::type Cat;
typedef typename find_param<ArgList, pointer_tag>::type Ptr;
typedef typename find_param<ArgList, reference_tag>::type Ref;
typedef boost::iterator<Category, Value, Distance, Pointer, Reference>
Traits0;
// Compute the defaults if necessary
typedef typename resolve_default<Val, default_value_type, Base, Traits0>::type
value_type;
// if getting default value type from iterator_traits, then it won't be const
typedef typename resolve_default<Diff, default_difference_type, Base,
Traits0>::type difference_type;
typedef typename resolve_default<Cat, default_iterator_category, Base,
Traits0>::type iterator_category;
typedef boost::iterator<iterator_category, value_type, difference_type,
Pointer, Reference> Traits1;
// Compute the defaults for pointer and reference. This is done as a
// separate step because the defaults for pointer and reference depend
// on value_type.
typedef typename resolve_default<Ptr, default_pointer, Base, Traits1>::type
pointer;
typedef typename resolve_default<Ref, default_reference, Base, Traits1>::type
reference;
public:
typedef boost::iterator<iterator_category,
typename remove_const<value_type>::type,
difference_type, pointer, reference> type;
};
// This is really a partial concept check for iterators. Should it
// be moved or done differently?
template <class Category, class Value, class Difference, class Pointer, class Reference>
struct validator
{
BOOST_STATIC_CONSTANT(
bool, is_input_or_output_iter
= (boost::is_convertible<Category*,std::input_iterator_tag*>::value
| boost::is_convertible<Category*,std::output_iterator_tag*>::value));
// Iterators should satisfy one of the known categories
BOOST_STATIC_ASSERT(is_input_or_output_iter);
// Iterators >= ForwardIterator must produce real references
// as required by the C++ standard requirements in Table 74.
BOOST_STATIC_CONSTANT(
bool, forward_iter_with_real_reference
= ((!boost::is_convertible<Category*,std::forward_iterator_tag*>::value)
| boost::is_same<Reference,Value&>::value
| boost::is_same<Reference,typename add_const<Value>::type&>::value));
BOOST_STATIC_ASSERT(forward_iter_with_real_reference);
};
} // namespace detail
// This macro definition is only temporary in this file
# if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
# define BOOST_ARG_DEPENDENT_TYPENAME typename
# else
# define BOOST_ARG_DEPENDENT_TYPENAME
# endif
//============================================================================
//iterator_adaptor - Adapts a generic piece of data as an iterator. Adaptation
// is especially easy if the data being adapted is itself an iterator
//
// Base - the base (usually iterator) type being wrapped.
//
// Policies - a set of policies determining how the resulting iterator
// works.
//
// Value - if supplied, the value_type of the resulting iterator, unless
// const. If const, a conforming compiler strips constness for the
// value_type. If not supplied, iterator_traits<Base>::value_type is used
//
// Reference - the reference type of the resulting iterator, and in
// particular, the result type of operator*(). If not supplied but
// Value is supplied, Value& is used. Otherwise
// iterator_traits<Base>::reference is used.
//
// Pointer - the pointer type of the resulting iterator, and in
// particular, the result type of operator->(). If not
// supplied but Value is supplied, Value* is used. Otherwise
// iterator_traits<Base>::pointer is used.
//
// Category - the iterator_category of the resulting iterator. If not
// supplied, iterator_traits<Base>::iterator_category is used.
//
// Distance - the difference_type of the resulting iterator. If not
// supplied, iterator_traits<Base>::difference_type is used.
template <class Base, class Policies,
class Value = ::boost::detail::default_argument,
class Reference = ::boost::detail::default_argument,
class Pointer = ::boost::detail::default_argument,
class Category = ::boost::detail::default_argument,
class Distance = ::boost::detail::default_argument
>
struct iterator_adaptor :
#ifdef BOOST_RELOPS_AMBIGUITY_BUG
iterator_comparisons<
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance>,
typename detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category, Distance>::type
>
#else
detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category,Distance>::type
#endif
{
typedef iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance> self;
public:
typedef detail::iterator_adaptor_traits_gen<Base,Value,Reference,Pointer,Category,Distance> TraitsGen;
typedef typename TraitsGen::type Traits;
typedef typename Traits::difference_type difference_type;
typedef typename Traits::value_type value_type;
typedef typename Traits::pointer pointer;
typedef typename Traits::reference reference;
typedef typename Traits::iterator_category iterator_category;
typedef Base base_type;
typedef Policies policies_type;
private:
typedef detail::validator<
iterator_category,value_type,difference_type,pointer,reference
> concept_check;
public:
iterator_adaptor()
{
}
explicit
iterator_adaptor(const Base& it, const Policies& p = Policies())
: m_iter_p(it, p) {
policies().initialize(base());
}
template <class Iter2, class Value2, class Pointer2, class Reference2>
iterator_adaptor (
const iterator_adaptor<Iter2,Policies,Value2,Reference2,Pointer2,Category,Distance>& src)
: m_iter_p(src.base(), src.policies())
{
policies().initialize(base());
}
#if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 || defined(__BORLANDC__)
// This is required to prevent a bug in how VC++ generates
// the assignment operator for compressed_pair
iterator_adaptor& operator= (const iterator_adaptor& x) {
m_iter_p = x.m_iter_p;
return *this;
}
#endif
reference operator*() const {
return policies().dereference(*this);
}
#ifdef BOOST_MSVC
# pragma warning(push)
# pragma warning( disable : 4284 )
#endif
typename boost::detail::operator_arrow_result_generator<value_type,reference,pointer>::type
operator->() const
{ return detail::operator_arrow(*this, iterator_category()); }
#ifdef BOOST_MSVC
# pragma warning(pop)
#endif
value_type operator[](difference_type n) const
{ return *(*this + n); }
self& operator++() {
#if !defined(__MWERKS__) || __MWERKS__ >= 0x2405
policies().increment(*this);
#else
// Odd bug, MWERKS couldn't deduce the type for the member template
// Workaround by explicitly specifying the type.
policies().increment<self>(*this);
#endif
return *this;
}
self operator++(int) { self tmp(*this); ++*this; return tmp; }
self& operator--() {
#if !defined(__MWERKS__) || __MWERKS__ >= 0x2405
policies().decrement(*this);
#else
policies().decrement<self>(*this);
#endif
return *this;
}
self operator--(int) { self tmp(*this); --*this; return tmp; }
self& operator+=(difference_type n) {
policies().advance(*this, n);
return *this;
}
self& operator-=(difference_type n) {
policies().advance(*this, -n);
return *this;
}
base_type const& base() const { return m_iter_p.first(); }
// Moved from global scope to avoid ambiguity with the operator-() which
// subtracts iterators from one another.
self operator-(difference_type x) const
{ self result(*this); return result -= x; }
private:
compressed_pair<Base,Policies> m_iter_p;
public: // implementation details (too many compilers have trouble when these are private).
base_type& base() { return m_iter_p.first(); }
Policies& policies() { return m_iter_p.second(); }
const Policies& policies() const { return m_iter_p.second(); }
};
template <class Base, class Policies, class Value, class Reference, class Pointer,
class Category, class Distance1, class Distance2>
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance1>
operator+(
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance1> p,
Distance2 x)
{
return p += x;
}
template <class Base, class Policies, class Value, class Reference, class Pointer,
class Category, class Distance1, class Distance2>
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance1>
operator+(
Distance2 x,
iterator_adaptor<Base,Policies,Value,Reference,Pointer,Category,Distance1> p)
{
return p += x;
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2, class Category,
class Distance>
typename iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>::difference_type
operator-(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
typedef typename iterator_adaptor<Iterator1,Policies,Value1,Reference1,
Pointer1,Category,Distance>::difference_type difference_type;
return x.policies().distance(y, x);
}
#ifndef BOOST_RELOPS_AMBIGUITY_BUG
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator==(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return x.policies().equal(x, y);
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator<(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return x.policies().distance(y, x) < 0;
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator>(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return x.policies().distance(y, x) > 0;
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator>=(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return x.policies().distance(y, x) >= 0;
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator<=(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return x.policies().distance(y, x) <= 0;
}
template <class Iterator1, class Iterator2, class Policies, class Value1, class Value2,
class Reference1, class Reference2, class Pointer1, class Pointer2,
class Category, class Distance>
inline bool
operator!=(
const iterator_adaptor<Iterator1,Policies,Value1,Reference1,Pointer1,Category,Distance>& x,
const iterator_adaptor<Iterator2,Policies,Value2,Reference2,Pointer2,Category,Distance>& y)
{
return !x.policies().equal(x, y);
}
#endif
//=============================================================================
// Transform Iterator Adaptor
//
// Upon deference, apply some unary function object and return the
// result by value.
template <class AdaptableUnaryFunction>
struct transform_iterator_policies : public default_iterator_policies
{
transform_iterator_policies() { }
transform_iterator_policies(const AdaptableUnaryFunction& f) : m_f(f) { }
template <class IteratorAdaptor>
typename IteratorAdaptor::reference
dereference(const IteratorAdaptor& iter) const
{ return m_f(*iter.base()); }
AdaptableUnaryFunction m_f;
};
template <class AdaptableUnaryFunction, class Iterator>
class transform_iterator_generator
{
typedef typename AdaptableUnaryFunction::result_type value_type;
public:
typedef iterator_adaptor<Iterator,
transform_iterator_policies<AdaptableUnaryFunction>,
value_type, value_type, value_type*, std::input_iterator_tag>
type;
};
template <class AdaptableUnaryFunction, class Iterator>
inline typename transform_iterator_generator<AdaptableUnaryFunction,Iterator>::type
make_transform_iterator(
Iterator base,
const AdaptableUnaryFunction& f = AdaptableUnaryFunction())
{
typedef typename transform_iterator_generator<AdaptableUnaryFunction,Iterator>::type result_t;
return result_t(base, f);
}
//=============================================================================
// Indirect Iterators Adaptor
// Given a pointer to pointers (or iterator to iterators),
// apply a double dereference inside operator*().
//
// We use the term "outer" to refer to the first level iterator type
// and "inner" to refer to the second level iterator type. For
// example, given T**, T* is the inner iterator type and T** is the
// outer iterator type. Also, const T* would be the const inner
// iterator.
// We tried to implement this with transform_iterator, but that required
// using boost::remove_ref, which is not compiler portable.
struct indirect_iterator_policies : public default_iterator_policies
{
template <class IteratorAdaptor>
typename IteratorAdaptor::reference dereference(const IteratorAdaptor& x) const
{ return **x.base(); }
};
namespace detail {
# if !defined(BOOST_MSVC) || BOOST_MSVC > 1300 // strangely instantiated even when unused! Maybe try a recursive template someday ;-)
template <class T>
struct traits_of_value_type {
typedef typename boost::detail::iterator_traits<T>::value_type outer_value;
typedef typename boost::detail::iterator_traits<outer_value>::value_type value_type;
typedef typename boost::detail::iterator_traits<outer_value>::reference reference;
typedef typename boost::detail::iterator_traits<outer_value>::pointer pointer;
};
# endif
}
template <class OuterIterator, // Mutable or Immutable, does not matter
class Value
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::value_type
#endif
, class Reference
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::reference
#else
= Value &
#endif
, class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<
OuterIterator>::iterator_category
, class Pointer
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::pointer
#else
= Value*
#endif
>
struct indirect_iterator_generator
{
typedef iterator_adaptor<OuterIterator,
indirect_iterator_policies,Value,Reference,Pointer,Category> type;
};
template <class OuterIterator, // Mutable or Immutable, does not matter
class Value
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::value_type
#endif
, class Reference
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::reference
#else
= Value &
#endif
, class ConstReference = Value const&
, class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<
OuterIterator>::iterator_category
, class Pointer
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
= BOOST_ARG_DEPENDENT_TYPENAME detail::traits_of_value_type<
OuterIterator>::pointer
#else
= Value*
#endif
, class ConstPointer = Value const*
>
struct indirect_iterator_pair_generator
{
typedef typename indirect_iterator_generator<OuterIterator,
Value, Reference,Category,Pointer>::type iterator;
typedef typename indirect_iterator_generator<OuterIterator,
Value, ConstReference,Category,ConstPointer>::type const_iterator;
};
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300
template <class OuterIterator>
inline typename indirect_iterator_generator<OuterIterator>::type
make_indirect_iterator(OuterIterator base)
{
typedef typename indirect_iterator_generator
<OuterIterator>::type result_t;
return result_t(base);
}
#endif
//=============================================================================
// Reverse Iterators Adaptor
struct reverse_iterator_policies : public default_iterator_policies
{
template <class IteratorAdaptor>
typename IteratorAdaptor::reference dereference(const IteratorAdaptor& x) const
{ return *boost::prior(x.base()); }
template <class BidirectionalIterator>
void increment(BidirectionalIterator& x) const
{ --x.base(); }
template <class BidirectionalIterator>
void decrement(BidirectionalIterator& x) const
{ ++x.base(); }
template <class BidirectionalIterator, class DifferenceType>
void advance(BidirectionalIterator& x, DifferenceType n) const
{ x.base() -= n; }
template <class Iterator1, class Iterator2>
typename Iterator1::difference_type distance(
const Iterator1& x, const Iterator2& y) const
{ return x.base() - y.base(); }
template <class Iterator1, class Iterator2>
bool equal(const Iterator1& x, const Iterator2& y) const
{ return x.base() == y.base(); }
};
template <class BidirectionalIterator,
class Value = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<BidirectionalIterator>::value_type,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<BidirectionalIterator,Value>::reference,
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<BidirectionalIterator,Value>::pointer,
class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<BidirectionalIterator>::iterator_category,
class Distance = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<BidirectionalIterator>::difference_type
>
struct reverse_iterator_generator
{
typedef iterator_adaptor<BidirectionalIterator,reverse_iterator_policies,
Value,Reference,Pointer,Category,Distance> type;
};
template <class BidirectionalIterator>
inline typename reverse_iterator_generator<BidirectionalIterator>::type
make_reverse_iterator(BidirectionalIterator base)
{
typedef typename reverse_iterator_generator<BidirectionalIterator>::type result_t;
return result_t(base);
}
//=============================================================================
// Projection Iterators Adaptor
template <class AdaptableUnaryFunction>
struct projection_iterator_policies : public default_iterator_policies
{
projection_iterator_policies() { }
projection_iterator_policies(const AdaptableUnaryFunction& f) : m_f(f) { }
template <class IteratorAdaptor>
typename IteratorAdaptor::reference dereference(IteratorAdaptor const& iter) const {
return m_f(*iter.base());
}
AdaptableUnaryFunction m_f;
};
template <class AdaptableUnaryFunction, class Iterator>
class projection_iterator_generator {
typedef typename AdaptableUnaryFunction::result_type value_type;
typedef projection_iterator_policies<AdaptableUnaryFunction> policies;
public:
typedef iterator_adaptor<Iterator,policies,value_type,value_type&,value_type*> type;
};
template <class AdaptableUnaryFunction, class Iterator>
class const_projection_iterator_generator {
typedef typename AdaptableUnaryFunction::result_type value_type;
typedef projection_iterator_policies<AdaptableUnaryFunction> policies;
public:
typedef iterator_adaptor<Iterator,policies,value_type,const value_type&,const value_type*> type;
};
template <class AdaptableUnaryFunction, class Iterator, class ConstIterator>
struct projection_iterator_pair_generator {
typedef typename projection_iterator_generator<AdaptableUnaryFunction, Iterator>::type iterator;
typedef typename const_projection_iterator_generator<AdaptableUnaryFunction, ConstIterator>::type const_iterator;
};
template <class AdaptableUnaryFunction, class Iterator>
inline typename projection_iterator_generator<AdaptableUnaryFunction, Iterator>::type
make_projection_iterator(
Iterator iter,
const AdaptableUnaryFunction& f = AdaptableUnaryFunction())
{
typedef typename projection_iterator_generator<AdaptableUnaryFunction, Iterator>::type result_t;
return result_t(iter, f);
}
template <class AdaptableUnaryFunction, class Iterator>
inline typename const_projection_iterator_generator<AdaptableUnaryFunction, Iterator>::type
make_const_projection_iterator(
Iterator iter,
const AdaptableUnaryFunction& f = AdaptableUnaryFunction())
{
typedef typename const_projection_iterator_generator<AdaptableUnaryFunction, Iterator>::type result_t;
return result_t(iter, f);
}
//=============================================================================
// Filter Iterator Adaptor
template <class Predicate, class Iterator>
class filter_iterator_policies
{
public:
filter_iterator_policies() { }
filter_iterator_policies(const Predicate& p, const Iterator& end)
: m_predicate(p), m_end(end) { }
void initialize(Iterator& x) {
satisfy_predicate(x);
}
// The Iter template argument is neccessary for compatibility with a MWCW
// bug workaround
template <class IteratorAdaptor>
void increment(IteratorAdaptor& x) {
++x.base();
satisfy_predicate(x.base());
}
template <class IteratorAdaptor>
typename IteratorAdaptor::reference dereference(const IteratorAdaptor& x) const
{ return *x.base(); }
template <class IteratorAdaptor1, class IteratorAdaptor2>
bool equal(const IteratorAdaptor1& x, const IteratorAdaptor2& y) const
{ return x.base() == y.base(); }
private:
void satisfy_predicate(Iterator& iter);
Predicate m_predicate;
Iterator m_end;
};
template <class Predicate, class Iterator>
void filter_iterator_policies<Predicate,Iterator>::satisfy_predicate(
Iterator& iter)
{
while (m_end != iter && !m_predicate(*iter))
++iter;
}
namespace detail {
// A type generator returning Base if T is derived from Base, and T otherwise.
template <class Base, class T>
struct reduce_to_base_class
{
typedef typename if_true<(
::boost::is_convertible<T*,Base*>::value
)>::template then<Base,T>::type type;
};
// "Steps down" the category of iterators below bidirectional so the category
// can be used with filter iterators.
template <class Iterator>
struct non_bidirectional_category
{
# if !defined(__MWERKS__) || __MWERKS__ > 0x2406
typedef typename reduce_to_base_class<
std::forward_iterator_tag,
typename iterator_traits<Iterator>::iterator_category
>::type type;
private:
// For some reason, putting this assertion in filter_iterator_generator fails inexplicably under MSVC
BOOST_STATIC_CONSTANT(
bool, is_bidirectional
= (!boost::is_convertible<type*, std::bidirectional_iterator_tag*>::value));
BOOST_STATIC_ASSERT(is_bidirectional);
# else
// is_convertible doesn't work with MWERKS
typedef typename iterator_traits<Iterator>::iterator_category input_category;
public:
typedef typename if_true<(
boost::is_same<input_category,std::random_access_iterator_tag>::value
|| boost::is_same<input_category,std::bidirectional_iterator_tag>::value
)>::template then<
std::forward_iterator_tag,
input_category
>::type type;
# endif
};
}
template <class Predicate, class Iterator,
class Value = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::value_type,
class Reference = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::reference,
class Pointer = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_defaults<Iterator,Value>::pointer,
class Category = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::non_bidirectional_category<Iterator>::type,
class Distance = BOOST_ARG_DEPENDENT_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type
>
class filter_iterator_generator {
BOOST_STATIC_CONSTANT(bool, is_bidirectional
= (boost::is_convertible<Category*, std::bidirectional_iterator_tag*>::value));
#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300 // I don't have any idea why this occurs, but it doesn't seem to hurt too badly.
BOOST_STATIC_ASSERT(!is_bidirectional);
#endif
typedef filter_iterator_policies<Predicate,Iterator> policies_type;
public:
typedef iterator_adaptor<Iterator,policies_type,
Value,Reference,Pointer,Category,Distance> type;
};
// This keeps MSVC happy; it doesn't like to deduce default template arguments
// for template function return types
namespace detail {
template <class Predicate, class Iterator>
struct filter_generator {
typedef typename boost::filter_iterator_generator<Predicate,Iterator>::type type;
};
}
template <class Predicate, class Iterator>
inline typename detail::filter_generator<Predicate, Iterator>::type
make_filter_iterator(Iterator first, Iterator last, const Predicate& p = Predicate())
{
typedef filter_iterator_generator<Predicate, Iterator> Gen;
typedef filter_iterator_policies<Predicate,Iterator> policies_t;
typedef typename Gen::type result_t;
return result_t(first, policies_t(p, last));
}
} // namespace boost
# undef BOOST_ARG_DEPENDENT_TYPENAME
#endif