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negative indexes support added to *_nth, *_head and *_tail algorithms

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[SVN r32475]
This commit is contained in:
Pavol Droba
2006-01-31 12:36:32 +00:00
parent d9ebe5da13
commit dd11014682
5 changed files with 248 additions and 146 deletions
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330
include/boost/algorithm/string/detail/finder.hpp
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@ -90,7 +90,7 @@ namespace boost {
// find last functor -----------------------------------------------//
// find the last match a subsequnce in the sequence ( functor )
// find the last match a subseqeunce in the sequence ( functor )
/*
Returns a pair <begin,end> marking the subsequence in the sequence.
If the find fails, returns <End,End>
@ -200,7 +200,7 @@ namespace boost {
// find n-th functor -----------------------------------------------//
// find the n-th match of a subsequnce in the sequence ( functor )
// find the n-th match of a subsequence in the sequence ( functor )
/*
Returns a pair <begin,end> marking the subsequence in the sequence.
If the find fails, returns <End,End>
@ -212,12 +212,15 @@ namespace boost {
typedef first_finderF<
search_iterator_type,
PredicateT> first_finder_type;
typedef last_finderF<
search_iterator_type,
PredicateT> last_finder_type;
// Construction
template< typename SearchT >
nth_finderF(
const SearchT& Search,
unsigned int Nth,
int Nth,
PredicateT Comp) :
m_Search(begin(Search), end(Search)),
m_Nth(Nth),
@ -225,7 +228,7 @@ namespace boost {
nth_finderF(
search_iterator_type SearchBegin,
search_iterator_type SearchEnd,
unsigned int Nth,
int Nth,
PredicateT Comp) :
m_Search(SearchBegin, SearchEnd),
m_Nth(Nth),
@ -237,6 +240,26 @@ namespace boost {
operator()(
ForwardIteratorT Begin,
ForwardIteratorT End ) const
{
if(m_Nth>=0)
{
return find_forward(Begin, End, m_Nth);
}
else
{
return find_backward(Begin, End, -m_Nth);
}
}
private:
// Implementation helpers
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_forward(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
@ -245,13 +268,13 @@ namespace boost {
if( boost::empty(m_Search) )
return result_type( End, End );
// Instantiate find funtor
// Instantiate find functor
first_finder_type first_finder(
m_Search.begin(), m_Search.end(), m_Comp );
result_type M( Begin, Begin );
for( unsigned int n=0; n<=m_Nth; ++n )
for( unsigned int n=0; n<=N; ++n )
{
// find next match
M=first_finder( end(M), End );
@ -266,14 +289,101 @@ namespace boost {
return M;
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_backward(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
// Sanity check
if( boost::empty(m_Search) )
return result_type( End, End );
// Instantiate find functor
last_finder_type last_finder(
m_Search.begin(), m_Search.end(), m_Comp );
result_type M( End, End );
for( unsigned int n=1; n<=N; ++n )
{
// find next match
M=last_finder( Begin, begin(M) );
if ( !M )
{
// Subsequence not found, return
return M;
}
}
return M;
}
private:
iterator_range<search_iterator_type> m_Search;
unsigned int m_Nth;
int m_Nth;
PredicateT m_Comp;
};
// find head functor -----------------------------------------------//
// Find head implementation
template<typename ForwardIteratorT>
iterator_range<ForwardIteratorT>
find_head_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N )
{
typedef BOOST_STRING_TYPENAME boost::detail::
iterator_traits<ForwardIteratorT>::iterator_category category;
return find_head_impl( Begin, End, N, category() );
}
template<typename ForwardIteratorT>
iterator_range<ForwardIteratorT>
find_head_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N,
std::forward_iterator_tag )
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
input_iterator_type It=Begin;
for(
unsigned int Index=0;
Index<N && It!=End; ++Index,++It ) {};
return result_type( Begin, It );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_head_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N,
std::random_access_iterator_tag )
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
if ( (End<=Begin) || ( static_cast<unsigned int>(End-Begin) < N ) )
return result_type( Begin, End );
return result_type(Begin,Begin+N);
}
// find a head in the sequence ( functor )
/*
This functor find a head of the specified range. For
@ -283,7 +393,7 @@ namespace boost {
struct head_finderF
{
// Construction
head_finderF( unsigned int N ) : m_N(N) {}
head_finderF( int N ) : m_N(N) {}
// Operation
template< typename ForwardIteratorT >
@ -292,54 +402,99 @@ namespace boost {
ForwardIteratorT Begin,
ForwardIteratorT End ) const
{
typedef BOOST_STRING_TYPENAME boost::detail::
iterator_traits<ForwardIteratorT>::iterator_category category;
if(m_N>=0)
{
return find_head_impl( Begin, End, m_N );
}
else
{
iterator_range<ForwardIteratorT> Res=
find_tail_impl( Begin, End, -m_N );
return findit( Begin, End, category() );
return make_iterator_range(Begin, Res.begin());
}
}
private:
// Find operation implementation
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
findit(
ForwardIteratorT Begin,
ForwardIteratorT End,
std::forward_iterator_tag ) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
input_iterator_type It=Begin;
for(
unsigned int Index=0;
Index<m_N && It!=End; ++Index,++It ) {};
return result_type( Begin, It );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
findit(
ForwardIteratorT Begin,
ForwardIteratorT End,
std::random_access_iterator_tag ) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
if ( (End<=Begin) || ( static_cast<unsigned int>(End-Begin) < m_N ) )
return result_type( Begin, End );
return result_type(Begin,Begin+m_N);
}
private:
unsigned int m_N;
int m_N;
};
// find tail functor -----------------------------------------------//
// Operation
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_tail_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N )
{
typedef BOOST_STRING_TYPENAME boost::detail::
iterator_traits<ForwardIteratorT>::iterator_category category;
return find_tail_impl( Begin, End, N, category() );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_tail_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N,
std::forward_iterator_tag )
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
unsigned int Index=0;
input_iterator_type It=Begin;
input_iterator_type It2=Begin;
// Advance It2 by N increments
for( Index=0; Index<N && It2!=End; ++Index,++It2 ) {};
// Advance It, It2 to the end
for(; It2!=End; ++It,++It2 ) {};
return result_type( It, It2 );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_tail_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N,
std::bidirectional_iterator_tag )
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
input_iterator_type It=End;
for(
unsigned int Index=0;
Index<N && It!=Begin; ++Index,--It ) {};
return result_type( It, End );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
find_tail_impl(
ForwardIteratorT Begin,
ForwardIteratorT End,
unsigned int N,
std::random_access_iterator_tag )
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
if ( (End<=Begin) || ( static_cast<unsigned int>(End-Begin) < N ) )
return result_type( Begin, End );
return result_type( End-N, End );
}
// find a tail in the sequence ( functor )
/*
This functor find a tail of the specified range. For
@ -349,7 +504,7 @@ namespace boost {
struct tail_finderF
{
// Construction
tail_finderF( unsigned int N ) : m_N(N) {}
tail_finderF( int N ) : m_N(N) {}
// Operation
template< typename ForwardIteratorT >
@ -358,74 +513,21 @@ namespace boost {
ForwardIteratorT Begin,
ForwardIteratorT End ) const
{
typedef BOOST_STRING_TYPENAME boost::detail::
iterator_traits<ForwardIteratorT>::iterator_category category;
if(m_N>=0)
{
return find_tail_impl( Begin, End, m_N );
}
else
{
iterator_range<ForwardIteratorT> Res=
find_head_impl( Begin, End, -m_N );
return findit( Begin, End, category() );
return make_iterator_range(Res.end(), End);
}
}
private:
// Find operation implementation
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
findit(
ForwardIteratorT Begin,
ForwardIteratorT End,
std::forward_iterator_tag ) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
unsigned int Index=0;
input_iterator_type It=Begin;
input_iterator_type It2=Begin;
// Advance It2 by N incremets
for( Index=0; Index<m_N && It2!=End; ++Index,++It2 ) {};
// Advance It, It2 to the end
for(; It2!=End; ++It,++It2 ) {};
return result_type( It, It2 );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
findit(
ForwardIteratorT Begin,
ForwardIteratorT End,
std::bidirectional_iterator_tag ) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
input_iterator_type It=End;
for(
unsigned int Index=0;
Index<m_N && It!=Begin; ++Index,--It ) {};
return result_type( It, End );
}
template< typename ForwardIteratorT >
iterator_range<ForwardIteratorT>
findit(
ForwardIteratorT Begin,
ForwardIteratorT End,
std::random_access_iterator_tag ) const
{
typedef ForwardIteratorT input_iterator_type;
typedef iterator_range<ForwardIteratorT> result_type;
if ( (End<=Begin) || ( static_cast<unsigned int>(End-Begin) < m_N ) )
return result_type( Begin, End );
return result_type( End-m_N, End );
}
private:
unsigned int m_N;
int m_N;
};
// find token functor -----------------------------------------------//
@ -475,7 +577,7 @@ namespace boost {
}
else
{
// Advance by one possition
// Advance by one position
++It2;
}