boost/xpressive/regex_token_iterator.hpp
///////////////////////////////////////////////////////////////////////////////
/// \file regex_token_iterator.hpp
/// Contains the definition of regex_token_iterator, and STL-compatible iterator
/// for tokenizing a string using a regular expression.
//
// Copyright 2008 Eric Niebler. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_XPRESSIVE_REGEX_TOKEN_ITERATOR_HPP_EAN_10_04_2005
#define BOOST_XPRESSIVE_REGEX_TOKEN_ITERATOR_HPP_EAN_10_04_2005
// MS compatible compilers support #pragma once
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <vector>
#include <boost/assert.hpp>
#include <boost/mpl/assert.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/xpressive/regex_iterator.hpp>
namespace boost { namespace xpressive { namespace detail
{
//////////////////////////////////////////////////////////////////////////
// regex_token_iterator_impl
//
template<typename BidiIter>
struct regex_token_iterator_impl
: counted_base<regex_token_iterator_impl<BidiIter> >
{
typedef sub_match<BidiIter> value_type;
regex_token_iterator_impl
(
BidiIter begin
, BidiIter cur
, BidiIter end
, BidiIter next_search
, basic_regex<BidiIter> const &rex
, regex_constants::match_flag_type flags = regex_constants::match_default
, std::vector<int> subs = std::vector<int>(1, 0)
, int n = -2
, bool not_null = false
)
: iter_(begin, cur, end, next_search, rex, flags, not_null)
, result_()
, n_((-2 == n) ? (int)subs.size() - 1 : n)
, subs_()
{
BOOST_ASSERT(0 != subs.size());
this->subs_.swap(subs);
}
bool next()
{
if(-1 != this->n_)
{
BidiIter cur = this->iter_.state_.cur_;
if(0 != (++this->n_ %= (int)this->subs_.size()) || this->iter_.next())
{
this->result_ = (-1 == this->subs_[ this->n_ ])
? this->iter_.what_.prefix()
: this->iter_.what_[ this->subs_[ this->n_ ] ];
return true;
}
else if(-1 == this->subs_[ this->n_-- ] && cur != this->iter_.state_.end_)
{
this->result_ = value_type(cur, this->iter_.state_.end_, true);
return true;
}
}
return false;
}
bool equal_to(regex_token_iterator_impl<BidiIter> const &that) const
{
return this->iter_.equal_to(that.iter_) && this->n_ == that.n_;
}
regex_iterator_impl<BidiIter> iter_;
value_type result_;
int n_;
std::vector<int> subs_;
};
inline int get_mark_number(int i)
{
return i;
}
inline std::vector<int> to_vector(int subs)
{
return std::vector<int>(1, subs);
}
inline std::vector<int> const &to_vector(std::vector<int> const &subs)
{
return subs;
}
template<typename Int, std::size_t Size>
inline std::vector<int> to_vector(Int const (&sub_matches)[ Size ])
{
// so that people can specify sub-match indices inline with
// string literals, like "\1\2\3", leave off the trailing '\0'
std::size_t const size = Size - is_same<Int, char>::value;
std::vector<int> vect(size);
for(std::size_t i = 0; i < size; ++i)
{
vect[i] = get_mark_number(sub_matches[i]);
}
return vect;
}
template<typename Int>
inline std::vector<int> to_vector(std::vector<Int> const &sub_matches)
{
BOOST_MPL_ASSERT((is_convertible<Int, int>));
return std::vector<int>(sub_matches.begin(), sub_matches.end());
}
} // namespace detail
//////////////////////////////////////////////////////////////////////////
// regex_token_iterator
//
template<typename BidiIter>
struct regex_token_iterator
{
typedef basic_regex<BidiIter> regex_type;
typedef typename iterator_value<BidiIter>::type char_type;
typedef sub_match<BidiIter> value_type;
typedef std::ptrdiff_t difference_type;
typedef value_type const *pointer;
typedef value_type const &reference;
typedef std::forward_iterator_tag iterator_category;
/// INTERNAL ONLY
typedef detail::regex_token_iterator_impl<BidiIter> impl_type_;
/// \post \c *this is the end of sequence iterator.
regex_token_iterator()
: impl_()
{
}
/// \param begin The beginning of the character range to search.
/// \param end The end of the character range to search.
/// \param rex The regex pattern to search for.
/// \pre \c [begin,end) is a valid range.
regex_token_iterator
(
BidiIter begin
, BidiIter end
, basic_regex<BidiIter> const &rex
)
: impl_()
{
if(0 != rex.regex_id())
{
this->impl_ = new impl_type_(begin, begin, end, begin, rex);
this->next_();
}
}
/// \param begin The beginning of the character range to search.
/// \param end The end of the character range to search.
/// \param rex The regex pattern to search for.
/// \param args A let() expression with argument bindings for semantic actions.
/// \pre \c [begin,end) is a valid range.
template<typename LetExpr>
regex_token_iterator
(
BidiIter begin
, BidiIter end
, basic_regex<BidiIter> const &rex
, detail::let_<LetExpr> const &args
)
: impl_()
{
if(0 != rex.regex_id())
{
this->impl_ = new impl_type_(begin, begin, end, begin, rex);
detail::bind_args(args, this->impl_->iter_.what_);
this->next_();
}
}
/// \param begin The beginning of the character range to search.
/// \param end The end of the character range to search.
/// \param rex The regex pattern to search for.
/// \param flags Optional match flags, used to control how the expression is matched against the sequence. (See match_flag_type.)
/// \pre \c [begin,end) is a valid range.
/// \pre \c subs is either an integer greater or equal to -1,
/// or else an array or non-empty \c std::vector\<\> of such integers.
template<typename Subs>
regex_token_iterator
(
BidiIter begin
, BidiIter end
, basic_regex<BidiIter> const &rex
, Subs const &subs
, regex_constants::match_flag_type flags = regex_constants::match_default
)
: impl_()
{
if(0 != rex.regex_id())
{
this->impl_ = new impl_type_(begin, begin, end, begin, rex, flags, detail::to_vector(subs));
this->next_();
}
}
/// \param begin The beginning of the character range to search.
/// \param end The end of the character range to search.
/// \param rex The regex pattern to search for.
/// \param args A let() expression with argument bindings for semantic actions.
/// \param flags Optional match flags, used to control how the expression is matched against the sequence. (See match_flag_type.)
/// \pre \c [begin,end) is a valid range.
/// \pre \c subs is either an integer greater or equal to -1,
/// or else an array or non-empty \c std::vector\<\> of such integers.
template<typename Subs, typename LetExpr>
regex_token_iterator
(
BidiIter begin
, BidiIter end
, basic_regex<BidiIter> const &rex
, Subs const &subs
, detail::let_<LetExpr> const &args
, regex_constants::match_flag_type flags = regex_constants::match_default
)
: impl_()
{
if(0 != rex.regex_id())
{
this->impl_ = new impl_type_(begin, begin, end, begin, rex, flags, detail::to_vector(subs));
detail::bind_args(args, this->impl_->iter_.what_);
this->next_();
}
}
/// \post <tt>*this == that</tt>
regex_token_iterator(regex_token_iterator<BidiIter> const &that)
: impl_(that.impl_) // COW
{
}
/// \post <tt>*this == that</tt>
regex_token_iterator<BidiIter> &operator =(regex_token_iterator<BidiIter> const &that)
{
this->impl_ = that.impl_; // COW
return *this;
}
friend bool operator ==(regex_token_iterator<BidiIter> const &left, regex_token_iterator<BidiIter> const &right)
{
if(!left.impl_ || !right.impl_)
{
return !left.impl_ && !right.impl_;
}
return left.impl_->equal_to(*right.impl_);
}
friend bool operator !=(regex_token_iterator<BidiIter> const &left, regex_token_iterator<BidiIter> const &right)
{
return !(left == right);
}
value_type const &operator *() const
{
return this->impl_->result_;
}
value_type const *operator ->() const
{
return &this->impl_->result_;
}
/// If N == -1 then sets *this equal to the end of sequence iterator.
/// Otherwise if N+1 \< subs.size(), then increments N and sets result equal to
/// ((subs[N] == -1) ? value_type(what.prefix().str()) : value_type(what[subs[N]].str())).
/// Otherwise if what.prefix().first != what[0].second and if the element match_prev_avail is
/// not set in flags then sets it. Then locates the next match as if by calling
/// regex_search(what[0].second, end, what, *pre, flags), with the following variation:
/// in the event that the previous match found was of zero length (what[0].length() == 0)
/// then attempts to find a non-zero length match starting at what[0].second, only if that
/// fails and provided what[0].second != suffix().second does it look for a (possibly zero
/// length) match starting from what[0].second + 1. If such a match is found then sets N
/// equal to zero, and sets result equal to
/// ((subs[N] == -1) ? value_type(what.prefix().str()) : value_type(what[subs[N]].str())).
/// Otherwise if no further matches were found, then let last_end be the endpoint of the last
/// match that was found. Then if last_end != end and subs[0] == -1 sets N equal to -1 and
/// sets result equal to value_type(last_end, end). Otherwise sets *this equal to the end
/// of sequence iterator.
regex_token_iterator<BidiIter> &operator ++()
{
this->fork_(); // un-share the implementation
this->next_();
return *this;
}
regex_token_iterator<BidiIter> operator ++(int)
{
regex_token_iterator<BidiIter> tmp(*this);
++*this;
return tmp;
}
private:
/// INTERNAL ONLY
void fork_()
{
if(1 != this->impl_->use_count())
{
intrusive_ptr<impl_type_> clone = new impl_type_
(
this->impl_->iter_.state_.begin_
, this->impl_->iter_.state_.cur_
, this->impl_->iter_.state_.end_
, this->impl_->iter_.state_.next_search_
, this->impl_->iter_.rex_
, this->impl_->iter_.flags_
, this->impl_->subs_
, this->impl_->n_
, this->impl_->iter_.not_null_
);
// only copy the match_results struct if we have to. Note: if the next call
// to impl_->next() will return false or call regex_search, we don't need to
// copy the match_results struct.
if(-1 != this->impl_->n_ && this->impl_->n_ + 1 != static_cast<int>(this->impl_->subs_.size()))
{
// BUGBUG This is expensive -- it causes the sequence_stack to be cleared.
// Find a better way
clone->iter_.what_ = this->impl_->iter_.what_;
}
else
{
// At the very least, copy the action args
detail::core_access<BidiIter>::get_action_args(clone->iter_.what_)
= detail::core_access<BidiIter>::get_action_args(this->impl_->iter_.what_);
}
this->impl_.swap(clone);
}
}
/// INTERNAL ONLY
void next_()
{
BOOST_ASSERT(this->impl_ && 1 == this->impl_->use_count());
if(!this->impl_->next())
{
this->impl_ = 0;
}
}
intrusive_ptr<impl_type_> impl_;
};
}} // namespace boost::xpressive
#endif