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new implementation for (const_)reverse_iterator to cope with issue #93
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@nlohmann
nlohmann committed Jul 7, 2015
1 parent 12d174d commit 19d550c
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Showing 3 changed files with 680 additions and 25 deletions.
166 changes: 155 additions & 11 deletions src/json.hpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5239,18 +5239,95 @@ class basic_json
internal_iterator m_it = internal_iterator();
};

/// a reverse random access iterator for the basic_json class
/*!
@brief a reverse random access iterator for the basic_json class
The reverse iterator is realized with the `std::reverse_iterator` adaptor.
This adaptor does not automatically inherit all functionality from the
base iterator class, so some functions need to be explicitly implemented
by either delegating them to the base class or by using the `base()`
function to access the underlying base iterator.
The following operators are implicitly inherited:
- `operator==`, `operator!=`, `operator<`, `operator<=`, `operator>`,
`operator>=`
- `operator-=`
- `operator->`, `operator*`
*/
class reverse_iterator : public std::reverse_iterator<typename basic_json::iterator>
{
public:
reverse_iterator(const typename
std::reverse_iterator<typename basic_json::iterator>::iterator_type&
it)
: std::reverse_iterator<basic_json::iterator>(it) {}
/// shortcut to the reverse iterator adaptor
using base_iterator = std::reverse_iterator<typename basic_json::iterator>;

reverse_iterator(const std::reverse_iterator<typename basic_json::iterator>& it)
: std::reverse_iterator<typename basic_json::iterator>(it)
{}
/// create reverse iterator from iterator
reverse_iterator(const typename base_iterator::iterator_type& it)
: base_iterator(it) {}

/// create reverse iterator from base class
reverse_iterator(const base_iterator& it) : base_iterator(it) {}

/// post-increment (it++)
reverse_iterator operator++(int)
{
return base_iterator::operator++(1);
}

/// pre-increment (++it)
reverse_iterator& operator++()
{
base_iterator::operator++();
return *this;
}

/// post-decrement (it--)
reverse_iterator operator--(int)
{
return base_iterator::operator--(1);
}

/// pre-decrement (--it)
reverse_iterator& operator--()
{
base_iterator::operator--();
return *this;
}

/// add to iterator
reverse_iterator& operator+=(difference_type i)
{
base_iterator::operator+=(i);
return *this;
}

/// add to iterator
reverse_iterator operator+(difference_type i) const
{
auto result = *this;
result += i;
return result;
}

/// subtract from iterator
reverse_iterator operator-(difference_type i) const
{
auto result = *this;
result -= i;
return result;
}

/// return difference
difference_type operator-(const reverse_iterator& other) const
{
return this->base() - other.base();
}

/// access to successor
reference operator[](difference_type n) const
{
return *(this->operator+(n));
}

/// return the key of an object iterator
typename object_t::key_type key() const
Expand All @@ -5271,9 +5348,76 @@ class basic_json
class const_reverse_iterator : public std::reverse_iterator<typename basic_json::const_iterator>
{
public:
const_reverse_iterator(const typename
std::reverse_iterator<typename basic_json::const_iterator>::iterator_type& it)
: std::reverse_iterator<basic_json::const_iterator>(it) {}
/// shortcut to the reverse iterator adaptor
using base_iterator = std::reverse_iterator<typename basic_json::const_iterator>;

/// create reverse iterator from iterator
const_reverse_iterator(const typename base_iterator::iterator_type& it)
: base_iterator(it) {}

/// create reverse iterator from base class
const_reverse_iterator(const base_iterator& it) : base_iterator(it) {}

/// post-increment (it++)
const_reverse_iterator operator++(int)
{
return base_iterator::operator++(1);
}

/// pre-increment (++it)
const_reverse_iterator& operator++()
{
base_iterator::operator++();
return *this;
}

/// post-decrement (it--)
const_reverse_iterator operator--(int)
{
return base_iterator::operator--(1);
}

/// pre-decrement (--it)
const_reverse_iterator& operator--()
{
base_iterator::operator--();
return *this;
}

/// add to iterator
const_reverse_iterator& operator+=(difference_type i)
{
base_iterator::operator+=(i);
return *this;
}

/// add to iterator
const_reverse_iterator operator+(difference_type i) const
{
auto result = *this;
result += i;
return result;
}

/// subtract from iterator
const_reverse_iterator operator-(difference_type i) const
{
auto result = *this;
result -= i;
return result;
}

/// return difference
difference_type operator-(const const_reverse_iterator& other) const
{
return this->base() - other.base();
}

/// access to successor
const_reference operator[](difference_type n) const
{
return *(this->operator+(n));
}

/// return the key of an object iterator
typename object_t::key_type key() const
Expand Down
166 changes: 155 additions & 11 deletions src/json.hpp.re2c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5239,18 +5239,95 @@ class basic_json
internal_iterator m_it = internal_iterator();
};

/// a reverse random access iterator for the basic_json class
/*!
@brief a reverse random access iterator for the basic_json class

The reverse iterator is realized with the `std::reverse_iterator` adaptor.
This adaptor does not automatically inherit all functionality from the
base iterator class, so some functions need to be explicitly implemented
by either delegating them to the base class or by using the `base()`
function to access the underlying base iterator.

The following operators are implicitly inherited:

- `operator==`, `operator!=`, `operator<`, `operator<=`, `operator>`,
`operator>=`
- `operator-=`
- `operator->`, `operator*`
*/
class reverse_iterator : public std::reverse_iterator<typename basic_json::iterator>
{
public:
reverse_iterator(const typename
std::reverse_iterator<typename basic_json::iterator>::iterator_type&
it)
: std::reverse_iterator<basic_json::iterator>(it) {}
/// shortcut to the reverse iterator adaptor
using base_iterator = std::reverse_iterator<typename basic_json::iterator>;

reverse_iterator(const std::reverse_iterator<typename basic_json::iterator>& it)
: std::reverse_iterator<typename basic_json::iterator>(it)
{}
/// create reverse iterator from iterator
reverse_iterator(const typename base_iterator::iterator_type& it)
: base_iterator(it) {}

/// create reverse iterator from base class
reverse_iterator(const base_iterator& it) : base_iterator(it) {}

/// post-increment (it++)
reverse_iterator operator++(int)
{
return base_iterator::operator++(1);
}

/// pre-increment (++it)
reverse_iterator& operator++()
{
base_iterator::operator++();
return *this;
}

/// post-decrement (it--)
reverse_iterator operator--(int)
{
return base_iterator::operator--(1);
}

/// pre-decrement (--it)
reverse_iterator& operator--()
{
base_iterator::operator--();
return *this;
}

/// add to iterator
reverse_iterator& operator+=(difference_type i)
{
base_iterator::operator+=(i);
return *this;
}

/// add to iterator
reverse_iterator operator+(difference_type i) const
{
auto result = *this;
result += i;
return result;
}

/// subtract from iterator
reverse_iterator operator-(difference_type i) const
{
auto result = *this;
result -= i;
return result;
}

/// return difference
difference_type operator-(const reverse_iterator& other) const
{
return this->base() - other.base();
}

/// access to successor
reference operator[](difference_type n) const
{
return *(this->operator+(n));
}

/// return the key of an object iterator
typename object_t::key_type key() const
Expand All @@ -5271,9 +5348,76 @@ class basic_json
class const_reverse_iterator : public std::reverse_iterator<typename basic_json::const_iterator>
{
public:
const_reverse_iterator(const typename
std::reverse_iterator<typename basic_json::const_iterator>::iterator_type& it)
: std::reverse_iterator<basic_json::const_iterator>(it) {}
/// shortcut to the reverse iterator adaptor
using base_iterator = std::reverse_iterator<typename basic_json::const_iterator>;

/// create reverse iterator from iterator
const_reverse_iterator(const typename base_iterator::iterator_type& it)
: base_iterator(it) {}

/// create reverse iterator from base class
const_reverse_iterator(const base_iterator& it) : base_iterator(it) {}

/// post-increment (it++)
const_reverse_iterator operator++(int)
{
return base_iterator::operator++(1);
}

/// pre-increment (++it)
const_reverse_iterator& operator++()
{
base_iterator::operator++();
return *this;
}

/// post-decrement (it--)
const_reverse_iterator operator--(int)
{
return base_iterator::operator--(1);
}

/// pre-decrement (--it)
const_reverse_iterator& operator--()
{
base_iterator::operator--();
return *this;
}

/// add to iterator
const_reverse_iterator& operator+=(difference_type i)
{
base_iterator::operator+=(i);
return *this;
}

/// add to iterator
const_reverse_iterator operator+(difference_type i) const
{
auto result = *this;
result += i;
return result;
}

/// subtract from iterator
const_reverse_iterator operator-(difference_type i) const
{
auto result = *this;
result -= i;
return result;
}

/// return difference
difference_type operator-(const const_reverse_iterator& other) const
{
return this->base() - other.base();
}

/// access to successor
const_reference operator[](difference_type n) const
{
return *(this->operator+(n));
}

/// return the key of an object iterator
typename object_t::key_type key() const
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