This commit was manufactured by cvs2svn to create branch 'RC_1_31_0'.

[SVN r21650]
This commit is contained in:
nobody
2004-01-12 20:58:23 +00:00
parent c65ab1a129
commit f05bfdccb7
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Example
.......
This example fills an array with numbers and a second array with
pointers into the first array, using ``counting_iterator`` for both
tasks. Finally ``indirect_iterator`` is used to print out the numbers
into the first array via indirection through the second array.
::
int N = 7;
std::vector<int> numbers;
typedef std::vector<int>::iterator n_iter;
std::copy(boost::counting_iterator<int>(0),
boost::counting_iterator<int>(N),
std::back_inserter(numbers));
std::vector<std::vector<int>::iterator> pointers;
std::copy(boost::make_counting_iterator(numbers.begin()),
boost::make_counting_iterator(numbers.end()),
std::back_inserter(pointers));
std::cout << "indirectly printing out the numbers from 0 to "
<< N << std::endl;
std::copy(boost::make_indirect_iterator(pointers.begin()),
boost::make_indirect_iterator(pointers.end()),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
The output is::
indirectly printing out the numbers from 0 to 7
0 1 2 3 4 5 6
The source code for this example can be found `here`__.
__ ../example/counting_iterator_example.cpp

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Example
.......
This example uses ``filter_iterator`` and then
``make_filter_iterator`` to output only the positive integers from an
array of integers. Then ``make_filter_iterator`` is is used to output
the integers greater than ``-2``.
::
struct is_positive_number {
bool operator()(int x) { return 0 < x; }
};
int main()
{
int numbers_[] = { 0, -1, 4, -3, 5, 8, -2 };
const int N = sizeof(numbers_)/sizeof(int);
typedef int* base_iterator;
base_iterator numbers(numbers_);
// Example using filter_iterator
typedef boost::filter_iterator<is_positive_number, base_iterator>
FilterIter;
is_positive_number predicate;
FilterIter filter_iter_first(predicate, numbers, numbers + N);
FilterIter filter_iter_last(predicate, numbers + N, numbers + N);
std::copy(filter_iter_first, filter_iter_last, std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
// Example using make_filter_iterator()
std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N),
boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
// Another example using make_filter_iterator()
std::copy(
boost::make_filter_iterator(
std::bind2nd(std::greater<int>(), -2)
, numbers, numbers + N)
, boost::make_filter_iterator(
std::bind2nd(std::greater<int>(), -2)
, numbers + N, numbers + N)
, std::ostream_iterator<int>(std::cout, " ")
);
std::cout << std::endl;
return boost::exit_success;
}
The output is::
4 5 8
4 5 8
0 -1 4 5 8
The source code for this example can be found `here`__.
__ ../example/filter_iterator_example.cpp

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Example
.......
::
struct string_appender
{
string_appender(std::string& s)
: m_str(&s)
{}
void operator()(const std::string& x) const
{
*m_str += x;
}
std::string* m_str;
};
int main(int, char*[])
{
std::vector<std::string> x;
x.push_back("hello");
x.push_back(" ");
x.push_back("world");
x.push_back("!");
std::string s = "";
std::copy(x.begin(), x.end(),
boost::make_function_output_iterator(string_appender(s)));
std::cout << s << std::endl;
return 0;
}

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Example
.......
This example prints an array of characters, using
``indirect_iterator`` to access the array of characters through an
array of pointers. Next ``indirect_iterator`` is used with the
``transform`` algorithm to copy the characters (incremented by one) to
another array. A constant indirect iterator is used for the source and
a mutable indirect iterator is used for the destination. The last part
of the example prints the original array of characters, but this time
using the ``make_indirect_iterator`` helper function.
::
char characters[] = "abcdefg";
const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
char* pointers_to_chars[N]; // at the end.
for (int i = 0; i < N; ++i)
pointers_to_chars[i] = &characters[i];
// Example of using indirect_iterator
boost::indirect_iterator<char**, char>
indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
// Example of making mutable and constant indirect iterators
char mutable_characters[N];
char* pointers_to_mutable_chars[N];
for (int j = 0; j < N; ++j)
pointers_to_mutable_chars[j] = &mutable_characters[j];
boost::indirect_iterator<char* const*> mutable_indirect_first(pointers_to_mutable_chars),
mutable_indirect_last(pointers_to_mutable_chars + N);
boost::indirect_iterator<char* const*, char const> const_indirect_first(pointers_to_chars),
const_indirect_last(pointers_to_chars + N);
std::transform(const_indirect_first, const_indirect_last,
mutable_indirect_first, std::bind1st(std::plus<char>(), 1));
std::copy(mutable_indirect_first, mutable_indirect_last,
std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
// Example of using make_indirect_iterator()
std::copy(boost::make_indirect_iterator(pointers_to_chars),
boost::make_indirect_iterator(pointers_to_chars + N),
std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
The output is::
a,b,c,d,e,f,g,
b,c,d,e,f,g,h,
a,b,c,d,e,f,g,
The source code for this example can be found `here`__.
__ ../example/indirect_iterator_example.cpp

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++++++++++++++++++++++++++++
Interoperability Revisited
++++++++++++++++++++++++++++
:date: $Date$
:copyright: Copyright Thomas Witt 2004.
Problem
=======
The current iterator_facade specification makes it unneccessarily tedious to
implement interoperable iterators.
In the following text a simplified example of the current iterator_facade specification is used to
illustrate the problem.
In the current specification binary operators are implemented in the following way:
template <class Derived>
struct Facade
{
};
template <class T1, T2>
struct is_interoperable :
or_<
is_convertible<T1, T2>
, is_convertible<T2, T1>
>
{};
template<
class Derived1
, class Derived2
>
enable_if<is_interoperable<Derived1, Derived2>, bool> operator==(
Derived1 const& lhs
, Derived2 const& rhs
)
{
return static_cast<Derived1 const&>(lhs).equal_to(static_cast<Derived2 const&(rhs));
}
The problem with this is that operator== always forwards to Derived1::equal_to. The net effect is that the
following "obvious" implementation of to interoperable types does not quite work.
struct Mutable : Facade<Mutable>
{
bool equal_to(Mutable const&);
};
struct Constant : Facade<Constant>
{
Constant();
Constant(Constant const&);
Constant(Mutable const&);
...
bool equal_to(Constant const&);
};
Constant c;
Mutable m;
c == m; // ok, dispatched to Constant::equal_to
m == c; // !! error, dispatched to Mutable::equal_to
Instead the following "slightly" more complicated implementation is neccessary
struct Mutable : Facade<Mutable>
{
template <class T>
enable_if<is_convertible<Mutable, T> || is_convertible<T, Mutable>, bool>::type equal_to(T const&);
};
struct Constant : Tag<Constant>
{
Constant();
Constant(Constant const&);
Constant(Mutable const&);
template <class T>
enable_if<is_convertible<Constant, T> || is_convertible<T, Constant>, bool>::type equal_to(T const&);
};
Beside the fact that the code is significantly more complex to understand and to teach there is
a major design problem lurking here. Note that in both types equal_to is a function template with
an unconstrained argument T. This is neccessary so that further types can be made interoperable with
Mutable or Constant. Would Mutable be defined as
struct Mutable : Facade<Mutable>
{
bool equal_to(Mutable const&);
bool equal_to(Constant const&);
};
Constant and Mutable would still be interoperable but no further interoperable could be added
without changing Mutable. Even if this would be considered acceptable the current specification forces
a two way dependency between interoperable types. Note in the templated equal_to case this dependency
is implicitly created when specializing equal_to.
Solution
========
The two way dependency can be avoided by enabling type conversion in the binary operator
implementation. Note that this is the usual way interoperability betwween types is achieved
for binary operators and one reason why binary operators are usually implemented as non-members.
A simple implementation of this strategy would look like this
template<
class T1
, class T2
>
struct interoperable_base :
if_<
is_convertible<
T2
, T1
>
, T1
, T2>
{};
template<
class Derived1
, class Derived2
>
enable_if<is_interoperable<Derived1, Derived2>, bool> operator==(
Derived1 const& lhs
, Derived2 const& rhs
)
{
typedef interoperable_base<
Derived1
, Derived2
>::type Base;
return static_cast<Base const&>(lhs).equal_to(static_cast<Derived2 const&(rhs));
}
This way our original simple and "obvious" implementation would work again.
c == m; // ok, dispatched to Constant::equal_to
m == c; // ok, dispatched to Constant::equal_to, m converted to Constant
The backdraw of this approach is that a possibly costly conversion of iterator objects
is forced on the user even in cases where direct comparison could be implemented
in a much more efficient way. This problem arises especially for iterator_adaptor
specializations and can be significantly slow down the iteration over ranges. Given the fact
that iteration is a very basic operation this possible performance degradation is not
acceptable.
Luckily whe can have our cake and eat it by a slightly more clever implementation of the binary
operators.
template<
class Derived1
, class Derived2
>
enable_if<is_convertible<Derived2, Derived1>, bool> operator==(
Derived1 const& lhs
, Derived2 const& rhs
)
{
return static_cast<Derived1 const&>(lhs).equal_to(static_cast<Derived2 const&(rhs));
}
template<
class Derived1
, class Derived2
>
enable_if<is_convertible<Derived1, Derived2>, bool> operator==(
Derived1 const& lhs
, Derived2 const& rhs
)
{
return static_cast<Derived2 const&>(rhs).equal_to(static_cast<Derived1 const&(lhs));
}
Given our simple and obvious definition of Mutable and Constant nothing has changed yet.
c == m; // ok, dispatched to Constant::equal_to, m converted to Constant
m == c; // ok, dispatched to Constant::equal_to, m converted to Constant
But now the user can avoid the type conversion by supplying the appropriate overload in Constant
struct Constant : Facade<Constant>
{
Constant();
Constant(Constant const&);
Constant(Mutable const&);
...
bool equal_to(Constant const&);
bool equal_to(Mutable const&);
};
c == m; // ok, dispatched to Constant::equal_to(Mutable const&), no conversion
m == c; // ok, dispatched to Constant::equal_to(Mutable const&), no conversion
This definition of operator== introduces a possible ambiguity when both types are convertible
to each other. I don't think this is a problem as this behaviour is the same with concrete types.
I.e.
struct A {};
bool operator==(A, A);
struct B { B(A); };
bool operator==(B, B);
A a;
B b(a);
a == b; // error, ambiguous overload
Effect
======
Iterator implementations using iterator_facade look exactly as if they were
"hand-implemented" (I am working on better wording).
a) Less burden for the user
b) The definition (standardese) of specialized adpters might be easier
(This has to be proved yet)

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::
template <class Incrementable>
counting_iterator<Incrementable> make_counting_iterator(Incrementable x);
:Returns: An instance of ``counting_iterator<Incrementable>``
with ``current`` constructed from ``x``.

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::
template <class BidirectionalIterator>
reverse_iterator<BidirectionalIterator>n
make_reverse_iterator(BidirectionalIterator x);
:Returns: An instance of ``reverse_iterator<BidirectionalIterator>``
with a ``current`` constructed from ``x``.

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::
template <class UnaryFunction, class Iterator>
transform_iterator<UnaryFunction, Iterator>
make_transform_iterator(Iterator it, UnaryFunction fun);
:Returns: An instance of ``transform_iterator<UnaryFunction, Iterator>`` with ``m_f``
initialized to ``f`` and ``m_iterator`` initialized to ``x``.
::
template <class UnaryFunction, class Iterator>
transform_iterator<UnaryFunction, Iterator>
make_transform_iterator(Iterator it);
:Returns: An instance of ``transform_iterator<UnaryFunction, Iterator>`` with ``m_f``
default constructed and ``m_iterator`` initialized to ``x``.

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::
using namespace boost;
int i = 0;
typedef std::vector< int > element_range_type;
typedef std::list< int > index_type;
static const int element_range_size = 10;
static const int index_size = 4;
element_range_type elements( element_range_size );
for(element_range_type::iterator el_it = elements.begin() ; el_it != elements.end() ; ++el_it)
*el_it = std::distance(elements.begin(), el_it);
index_type indices( index_size );
for(index_type::iterator i_it = indices.begin() ; i_it != indices.end() ; ++i_it )
*i_it = element_range_size - index_size + std::distance(indices.begin(), i_it);
std::reverse( indices.begin(), indices.end() );
typedef permutation_iterator< element_range_type::iterator, index_type::iterator > permutation_type;
permutation_type begin = make_permutation_iterator( elements.begin(), indices.begin() );
permutation_type it = begin;
permutation_type end = make_permutation_iterator( elements.begin(), indices.end() );
std::cout << "The original range is : ";
std::copy( elements.begin(), elements.end(), std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "The reindexing scheme is : ";
std::copy( indices.begin(), indices.end(), std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "The permutated range is : ";
std::copy( begin, end, std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "Elements at even indices in the permutation : ";
it = begin;
for(i = 0; i < index_size / 2 ; ++i, it+=2 ) std::cout << *it << " ";
std::cout << "\n";
std::cout << "Permutation backwards : ";
it = begin + (index_size);
assert( it != begin );
for( ; it-- != begin ; ) std::cout << *it << " ";
std::cout << "\n";
std::cout << "Iterate backward with stride 2 : ";
it = begin + (index_size - 1);
for(i = 0 ; i < index_size / 2 ; ++i, it-=2 ) std::cout << *it << " ";
std::cout << "\n";
The output is::
The original range is : 0 1 2 3 4 5 6 7 8 9
The reindexing scheme is : 9 8 7 6
The permutated range is : 9 8 7 6
Elements at even indices in the permutation : 9 7
Permutation backwards : 6 7 8 9
Iterate backward with stride 2 : 6 8
The source code for this example can be found `here`__.
__ ../example/permutation_iterator_example.cpp

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Example
.......
The following example prints an array of characters in reverse order
using ``reverse_iterator``.
::
char letters_[] = "hello world!";
const int N = sizeof(letters_)/sizeof(char) - 1;
typedef char* base_iterator;
base_iterator letters(letters_);
std::cout << "original sequence of letters:\t\t\t" << letters_ << std::endl;
boost::reverse_iterator<base_iterator>
reverse_letters_first(letters + N),
reverse_letters_last(letters);
std::cout << "sequence in reverse order:\t\t\t";
std::copy(reverse_letters_first, reverse_letters_last,
std::ostream_iterator<char>(std::cout));
std::cout << std::endl;
std::cout << "sequence in double-reversed (normal) order:\t";
std::copy(boost::make_reverse_iterator(reverse_letters_last),
boost::make_reverse_iterator(reverse_letters_first),
std::ostream_iterator<char>(std::cout));
std::cout << std::endl;
The output is::
original sequence of letters: hello world!
sequence in reverse order: !dlrow olleh
sequence in double-reversed (normal) order: hello world!
The source code for this example can be found `here`__.
__ ../example/reverse_iterator_example.cpp

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Example
.......
This is a simple example of using the transform_iterators class to
generate iterators that multiply (or add to) the value returned by
dereferencing the iterator. It would be cooler to use lambda library
in this example.
::
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
const int N = sizeof(x)/sizeof(int);
typedef boost::binder1st< std::multiplies<int> > Function;
typedef boost::transform_iterator<Function, int*> doubling_iterator;
doubling_iterator i(x, boost::bind1st(std::multiplies<int>(), 2)),
i_end(x + N, boost::bind1st(std::multiplies<int>(), 2));
std::cout << "multiplying the array by 2:" << std::endl;
while (i != i_end)
std::cout << *i++ << " ";
std::cout << std::endl;
std::cout << "adding 4 to each element in the array:" << std::endl;
std::copy(boost::make_transform_iterator(x, boost::bind1st(std::plus<int>(), 4)),
boost::make_transform_iterator(x + N, boost::bind1st(std::plus<int>(), 4)),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
The output is::
multiplying the array by 2:
2 4 6 8 10 12 14 16
adding 4 to each element in the array:
5 6 7 8 9 10 11 12
The source code for this example can be found `here`__.
__ ../example/transform_iterator_example.cpp

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// (C) Copyright Jeremy Siek 2000-2004.
// 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.
#include <boost/config.hpp>
#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
#include <boost/iterator/counting_iterator.hpp>
#include <boost/iterator/indirect_iterator.hpp>
#include <boost/cstdlib.hpp>
int main(int, char*[])
{
// Example of using counting_iterator
std::cout << "counting from 0 to 4:" << std::endl;
boost::counting_iterator<int> first(0), last(4);
std::copy(first, last, std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
// Example of using counting iterator to create an array of pointers.
int N = 7;
std::vector<int> numbers;
typedef std::vector<int>::iterator n_iter;
// Fill "numbers" array with [0,N)
std::copy(
boost::counting_iterator<int>(0)
, boost::counting_iterator<int>(N)
, std::back_inserter(numbers));
std::vector<std::vector<int>::iterator> pointers;
// Use counting iterator to fill in the array of pointers.
// causes an ICE with MSVC6
std::copy(boost::make_counting_iterator(numbers.begin()),
boost::make_counting_iterator(numbers.end()),
std::back_inserter(pointers));
// Use indirect iterator to print out numbers by accessing
// them through the array of pointers.
std::cout << "indirectly printing out the numbers from 0 to "
<< N << std::endl;
std::copy(boost::make_indirect_iterator(pointers.begin()),
boost::make_indirect_iterator(pointers.end()),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
return boost::exit_success;
}

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// (C) Copyright Jeremy Siek 1999-2004.
// 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.
#include <boost/config.hpp>
#include <algorithm>
#include <functional>
#include <iostream>
#include <boost/iterator/filter_iterator.hpp>
#include <boost/cstdlib.hpp> // for exit_success
struct is_positive_number {
bool operator()(int x) { return 0 < x; }
};
int main()
{
int numbers_[] = { 0, -1, 4, -3, 5, 8, -2 };
const int N = sizeof(numbers_)/sizeof(int);
typedef int* base_iterator;
base_iterator numbers(numbers_);
// Example using make_filter_iterator()
std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N),
boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
// Example using filter_iterator
typedef boost::filter_iterator<is_positive_number, base_iterator>
FilterIter;
is_positive_number predicate;
FilterIter filter_iter_first(predicate, numbers, numbers + N);
FilterIter filter_iter_last(predicate, numbers + N, numbers + N);
std::copy(filter_iter_first, filter_iter_last, std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
// Another example using make_filter_iterator()
std::copy(
boost::make_filter_iterator(
std::bind2nd(std::greater<int>(), -2)
, numbers, numbers + N)
, boost::make_filter_iterator(
std::bind2nd(std::greater<int>(), -2)
, numbers + N, numbers + N)
, std::ostream_iterator<int>(std::cout, " ")
);
std::cout << std::endl;
return boost::exit_success;
}

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// (C) Copyright Jeremy Siek 2001-2004.
// 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:
// 27 Feb 2001 Jeremy Siek
// Initial checkin.
#include <iostream>
#include <string>
#include <vector>
#include <boost/function_output_iterator.hpp>
struct string_appender
{
string_appender(std::string& s)
: m_str(&s)
{}
void operator()(const std::string& x) const
{
*m_str += x;
}
std::string* m_str;
};
int main(int, char*[])
{
std::vector<std::string> x;
x.push_back("hello");
x.push_back(" ");
x.push_back("world");
x.push_back("!");
std::string s = "";
std::copy(x.begin(), x.end(),
boost::make_function_output_iterator(string_appender(s)));
std::cout << s << std::endl;
return 0;
}

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// (C) Copyright Jeremy Siek 2000-2004.
// 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.
#include <boost/config.hpp>
#include <vector>
#include <iostream>
#include <iterator>
#include <functional>
#include <algorithm>
#include <boost/iterator/indirect_iterator.hpp>
int main(int, char*[])
{
char characters[] = "abcdefg";
const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
char* pointers_to_chars[N]; // at the end.
for (int i = 0; i < N; ++i)
pointers_to_chars[i] = &characters[i];
// Example of using indirect_iterator
boost::indirect_iterator<char**, char>
indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
// Example of making mutable and constant indirect iterators
char mutable_characters[N];
char* pointers_to_mutable_chars[N];
for (int j = 0; j < N; ++j)
pointers_to_mutable_chars[j] = &mutable_characters[j];
boost::indirect_iterator<char* const*> mutable_indirect_first(pointers_to_mutable_chars),
mutable_indirect_last(pointers_to_mutable_chars + N);
boost::indirect_iterator<char* const*, char const> const_indirect_first(pointers_to_chars),
const_indirect_last(pointers_to_chars + N);
std::transform(const_indirect_first, const_indirect_last,
mutable_indirect_first, std::bind1st(std::plus<char>(), 1));
std::copy(mutable_indirect_first, mutable_indirect_last,
std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
// Example of using make_indirect_iterator()
std::copy(boost::make_indirect_iterator(pointers_to_chars),
boost::make_indirect_iterator(pointers_to_chars + N),
std::ostream_iterator<char>(std::cout, ","));
std::cout << std::endl;
return 0;
}

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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 NODE_DWA2004110_HPP
# define NODE_DWA2004110_HPP
# include <iostream>
// Polymorphic list node base class
struct node_base
{
node_base() : m_next(0) {}
virtual ~node_base()
{
delete m_next;
}
node_base* next() const
{
return m_next;
}
virtual void print(std::ostream& s) const = 0;
virtual void double_me() = 0;
void append(node_base* p)
{
if (m_next)
m_next->append(p);
else
m_next = p;
}
private:
node_base* m_next;
};
inline std::ostream& operator<<(std::ostream& s, node_base const& n)
{
n.print(s);
return s;
}
template <class T>
struct node : node_base
{
node(T x)
: m_value(x)
{}
void print(std::ostream& s) const { s << this->m_value; }
void double_me() { m_value += m_value; }
private:
T m_value;
};
#endif // NODE_DWA2004110_HPP

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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)
#include "node_iterator1.hpp"
#include <string>
#include <memory>
#include <iostream>
#include <algorithm>
#include <functional>
int main()
{
std::auto_ptr<node<int> > nodes(new node<int>(42));
nodes->append(new node<std::string>(" is greater than "));
nodes->append(new node<int>(13));
std::copy(
node_iterator(nodes.get()), node_iterator()
, std::ostream_iterator<node_base>(std::cout, " ")
);
std::cout << std::endl;
std::for_each(
node_iterator(nodes.get()), node_iterator()
, std::mem_fun_ref(&node_base::double_me)
);
std::copy(
node_iterator(nodes.get()), node_iterator()
, std::ostream_iterator<node_base>(std::cout, "/")
);
std::cout << std::endl;
}

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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 NODE_ITERATOR1_DWA2004110_HPP
# define NODE_ITERATOR1_DWA2004110_HPP
# include "node.hpp"
# include <boost/iterator/iterator_facade.hpp>
class node_iterator
: public boost::iterator_facade<
node_iterator
, node_base
, boost::forward_traversal_tag
>
{
public:
node_iterator()
: m_node(0)
{}
explicit node_iterator(node_base* p)
: m_node(p)
{}
private:
friend class boost::iterator_core_access;
void increment()
{ m_node = m_node->next(); }
bool equal(node_iterator const& other) const
{ return this->m_node == other.m_node; }
node_base& dereference() const
{ return *m_node; }
node_base* m_node;
};
#endif // NODE_ITERATOR1_DWA2004110_HPP

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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)
#include "node_iterator2.hpp"
#include <string>
#include <memory>
#include <iostream>
#include <algorithm>
#include <boost/mem_fn.hpp>
#include <cassert>
int main()
{
std::auto_ptr<node<int> > nodes(new node<int>(42));
nodes->append(new node<std::string>(" is greater than "));
nodes->append(new node<int>(13));
// Check interoperability
assert(node_iterator(nodes.get()) == node_const_iterator(nodes.get()));
assert(node_const_iterator(nodes.get()) == node_iterator(nodes.get()));
assert(node_iterator(nodes.get()) != node_const_iterator());
assert(node_const_iterator(nodes.get()) != node_iterator());
std::copy(
node_iterator(nodes.get()), node_iterator()
, std::ostream_iterator<node_base>(std::cout, " ")
);
std::cout << std::endl;
std::for_each(
node_iterator(nodes.get()), node_iterator()
, boost::mem_fn(&node_base::double_me)
);
std::copy(
node_const_iterator(nodes.get()), node_const_iterator()
, std::ostream_iterator<node_base>(std::cout, "/")
);
std::cout << std::endl;
return 0;
}

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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 NODE_ITERATOR2_DWA2004110_HPP
# define NODE_ITERATOR2_DWA2004110_HPP
# include "node.hpp"
# include <boost/iterator/iterator_adaptor.hpp>
# ifndef BOOST_NO_SFINAE
# include <boost/type_traits/is_convertible.hpp>
# include <boost/utility/enable_if.hpp>
# endif
template <class Value>
class node_iter
: public boost::iterator_adaptor<
node_iter<Value> // Derived
, Value* // Base
, boost::use_default // Value
, boost::forward_traversal_tag // CategoryOrTraversal
>
{
private:
struct enabler {}; // a private type avoids misuse
typedef boost::iterator_adaptor<
node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
> super_t;
public:
node_iter()
: super_t(0) {}
explicit node_iter(Value* p)
: super_t(p) {}
template <class OtherValue>
node_iter(
node_iter<OtherValue> const& other
# ifndef BOOST_NO_SFINAE
, typename boost::enable_if<
boost::is_convertible<OtherValue*,Value*>
, enabler
>::type = enabler()
# endif
)
: m_node(other.m_node) {}
private:
friend class boost::iterator_core_access;
void increment() { m_node = m_node->next(); }
};
typedef node_iter<node_base> node_iterator;
typedef node_iter<node_base const> node_const_iterator;
#endif // NODE_ITERATOR2_DWA2004110_HPP

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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)
#include "node_iterator3.hpp"
#include <string>
#include <memory>
#include <iostream>
#include <algorithm>
#include <boost/mem_fn.hpp>
#include <cassert>
int main()
{
std::auto_ptr<node<int> > nodes(new node<int>(42));
nodes->append(new node<std::string>(" is greater than "));
nodes->append(new node<int>(13));
// Check interoperability
assert(node_iterator(nodes.get()) == node_const_iterator(nodes.get()));
assert(node_const_iterator(nodes.get()) == node_iterator(nodes.get()));
assert(node_iterator(nodes.get()) != node_const_iterator());
assert(node_const_iterator(nodes.get()) != node_iterator());
std::copy(
node_iterator(nodes.get()), node_iterator()
, std::ostream_iterator<node_base>(std::cout, " ")
);
std::cout << std::endl;
std::for_each(
node_iterator(nodes.get()), node_iterator()
, boost::mem_fn(&node_base::double_me)
);
std::copy(
node_const_iterator(nodes.get()), node_const_iterator()
, std::ostream_iterator<node_base>(std::cout, "/")
);
std::cout << std::endl;
return 0;
}

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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 NODE_ITERATOR3_DWA2004110_HPP
# define NODE_ITERATOR3_DWA2004110_HPP
# include "node.hpp"
# include <boost/iterator/iterator_adaptor.hpp>
# ifndef BOOST_NO_SFINAE
# include <boost/type_traits/is_convertible.hpp>
# include <boost/utility/enable_if.hpp>
# endif
template <class Value>
class node_iter
: public boost::iterator_adaptor<
node_iter<Value> // Derived
, Value* // Base
, boost::use_default // Value
, boost::forward_traversal_tag // CategoryOrTraversal
>
{
private:
struct enabler {}; // a private type avoids misuse
typedef boost::iterator_adaptor<
node_iter<Value>, Value*, boost::use_default, boost::forward_traversal_tag
> super_t;
public:
node_iter()
: super_t(0) {}
explicit node_iter(Value* p)
: super_t(p) {}
template <class OtherValue>
node_iter(
node_iter<OtherValue> const& other
# ifndef BOOST_NO_SFINAE
, typename boost::enable_if<
boost::is_convertible<OtherValue*,Value*>
, enabler
>::type = enabler()
# endif
)
: m_node(other.m_node) {}
private:
friend class boost::iterator_core_access;
void increment() { this->base_reference() = this->base()->next(); }
};
typedef node_iter<node_base> node_iterator;
typedef node_iter<node_base const> node_const_iterator;
#endif // NODE_ITERATOR3_DWA2004110_HPP

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#include <iostream>
#include <vector>
#include <list>
#include <boost/iterator/permutation_iterator.hpp>
#include <boost/cstdlib.hpp>
int main() {
using namespace boost;
int i = 0;
typedef std::vector< int > element_range_type;
typedef std::list< int > index_type;
static const int element_range_size = 10;
static const int index_size = 4;
element_range_type elements( element_range_size );
for(element_range_type::iterator el_it = elements.begin() ; el_it != elements.end() ; ++el_it)
*el_it = std::distance(elements.begin(), el_it);
index_type indices( index_size );
for(index_type::iterator i_it = indices.begin() ; i_it != indices.end() ; ++i_it )
*i_it = element_range_size - index_size + std::distance(indices.begin(), i_it);
std::reverse( indices.begin(), indices.end() );
typedef permutation_iterator< element_range_type::iterator, index_type::iterator > permutation_type;
permutation_type begin = make_permutation_iterator( elements.begin(), indices.begin() );
permutation_type it = begin;
permutation_type end = make_permutation_iterator( elements.begin(), indices.end() );
std::cout << "The original range is : ";
std::copy( elements.begin(), elements.end(), std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "The reindexing scheme is : ";
std::copy( indices.begin(), indices.end(), std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "The permutated range is : ";
std::copy( begin, end, std::ostream_iterator< int >( std::cout, " " ) );
std::cout << "\n";
std::cout << "Elements at even indices in the permutation : ";
it = begin;
for(i = 0; i < index_size / 2 ; ++i, it+=2 ) std::cout << *it << " ";
std::cout << "\n";
std::cout << "Permutation backwards : ";
it = begin + (index_size);
assert( it != begin );
for( ; it-- != begin ; ) std::cout << *it << " ";
std::cout << "\n";
std::cout << "Iterate backward with stride 2 : ";
it = begin + (index_size - 1);
for(i = 0 ; i < index_size / 2 ; ++i, it-=2 ) std::cout << *it << " ";
std::cout << "\n";
return boost::exit_success;
}

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// (C) Copyright Jeremy Siek 2000-2004.
// 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.
#include <boost/config.hpp>
#include <iostream>
#include <algorithm>
#include <boost/iterator/reverse_iterator.hpp>
#include <boost/cstdlib.hpp>
int main(int, char*[])
{
char letters_[] = "hello world!";
const int N = sizeof(letters_)/sizeof(char) - 1;
typedef char* base_iterator;
base_iterator letters(letters_);
std::cout << "original sequence of letters:\t\t\t"
<< letters_ << std::endl;
// Use reverse_iterator to print a sequence of letters in reverse
// order.
boost::reverse_iterator<base_iterator>
reverse_letters_first(letters + N),
reverse_letters_last(letters);
std::cout << "sequence in reverse order:\t\t\t";
std::copy(reverse_letters_first, reverse_letters_last,
std::ostream_iterator<char>(std::cout));
std::cout << std::endl;
std::cout << "sequence in double-reversed (normal) order:\t";
std::copy(boost::make_reverse_iterator(reverse_letters_last),
boost::make_reverse_iterator(reverse_letters_first),
std::ostream_iterator<char>(std::cout));
std::cout << std::endl;
return boost::exit_success;
}

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// (C) Copyright Jeremy Siek 2000-2004.
// 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.
#include <functional>
#include <algorithm>
#include <iostream>
#include <boost/iterator/transform_iterator.hpp>
// What a bummer. We can't use std::binder1st with transform iterator
// because it does not have a default constructor. Here's a version
// that does.
namespace boost {
template <class Operation>
class binder1st
: public std::unary_function<typename Operation::second_argument_type,
typename Operation::result_type> {
protected:
Operation op;
typename Operation::first_argument_type value;
public:
binder1st() { } // this had to be added!
binder1st(const Operation& x,
const typename Operation::first_argument_type& y)
: op(x), value(y) {}
typename Operation::result_type
operator()(const typename Operation::second_argument_type& x) const {
return op(value, x);
}
};
template <class Operation, class T>
inline binder1st<Operation> bind1st(const Operation& op, const T& x) {
typedef typename Operation::first_argument_type arg1_type;
return binder1st<Operation>(op, arg1_type(x));
}
} // namespace boost
int
main(int, char*[])
{
// This is a simple example of using the transform_iterators class to
// generate iterators that multiply the value returned by dereferencing
// the iterator. In this case we are multiplying by 2.
// Would be cooler to use lambda library in this example.
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
const int N = sizeof(x)/sizeof(int);
typedef boost::binder1st< std::multiplies<int> > Function;
typedef boost::transform_iterator<Function, int*> doubling_iterator;
doubling_iterator i(x, boost::bind1st(std::multiplies<int>(), 2)),
i_end(x + N, boost::bind1st(std::multiplies<int>(), 2));
std::cout << "multiplying the array by 2:" << std::endl;
while (i != i_end)
std::cout << *i++ << " ";
std::cout << std::endl;
std::cout << "adding 4 to each element in the array:" << std::endl;
std::copy(boost::make_transform_iterator(x, boost::bind1st(std::plus<int>(), 4)),
boost::make_transform_iterator(x + N, boost::bind1st(std::plus<int>(), 4)),
std::ostream_iterator<int>(std::cout, " "));
std::cout << std::endl;
return 0;
}

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// Copyright David Abrahams 2004. Use, modification and distribution is
// subject to 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)
#include <boost/pointee.hpp>
#include <boost/type_traits/add_const.hpp>
#include "static_assert_same.hpp"
#include <memory>
#include <list>
template <class T, class Ref>
struct proxy_ptr
{
typedef T element_type;
struct proxy
{
operator Ref() const;
};
proxy operator*() const;
};
template <class T>
struct proxy_ref_ptr : proxy_ptr<T,T&>
{
};
template <class T>
struct proxy_value_ptr : proxy_ptr<T,T>
{
typedef typename boost::add_const<T>::type element_type;
};
struct X {
template <class T> X(T const&);
template <class T> operator T&() const;
};
BOOST_TT_BROKEN_COMPILER_SPEC(X)
int main()
{
STATIC_ASSERT_SAME(boost::pointee<proxy_ref_ptr<int> >::type, int);
STATIC_ASSERT_SAME(boost::pointee<proxy_ref_ptr<X> >::type, X);
STATIC_ASSERT_SAME(boost::pointee<proxy_ref_ptr<int const> >::type, int const);
STATIC_ASSERT_SAME(boost::pointee<proxy_ref_ptr<X const> >::type, X const);
STATIC_ASSERT_SAME(boost::pointee<proxy_value_ptr<int> >::type, int const);
STATIC_ASSERT_SAME(boost::pointee<proxy_value_ptr<X> >::type, X const);
STATIC_ASSERT_SAME(boost::pointee<proxy_value_ptr<int const> >::type, int const);
STATIC_ASSERT_SAME(boost::pointee<proxy_value_ptr<X const> >::type, X const);
STATIC_ASSERT_SAME(boost::pointee<int*>::type, int);
STATIC_ASSERT_SAME(boost::pointee<int const*>::type, int const);
STATIC_ASSERT_SAME(boost::pointee<X*>::type, X);
STATIC_ASSERT_SAME(boost::pointee<X const*>::type, X const);
STATIC_ASSERT_SAME(boost::pointee<std::auto_ptr<int> >::type, int);
STATIC_ASSERT_SAME(boost::pointee<std::auto_ptr<X> >::type, X);
STATIC_ASSERT_SAME(boost::pointee<std::auto_ptr<int const> >::type, int const);
STATIC_ASSERT_SAME(boost::pointee<std::auto_ptr<X const> >::type, X const);
STATIC_ASSERT_SAME(boost::pointee<std::list<int>::iterator >::type, int);
STATIC_ASSERT_SAME(boost::pointee<std::list<X>::iterator >::type, X);
STATIC_ASSERT_SAME(boost::pointee<std::list<int>::const_iterator >::type, int const);
STATIC_ASSERT_SAME(boost::pointee<std::list<X>::const_iterator >::type, X const);
return 0;
}