gecko-dev/xpcom/string/public/nsStringIterator.h

451 lines
11 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is Mozilla.
*
* The Initial Developer of the Original Code is Netscape
* Communications. Portions created by Netscape Communications are
* Copyright (C) 2001 by Netscape Communications. All
* Rights Reserved.
*
* Contributor(s):
* Scott Collins <scc@mozilla.org> (original author)
*/
#ifndef nsStringIterator_h___
#define nsStringIterator_h___
#ifndef nsStringFragment_h___
#include "nsStringFragment.h"
#endif
#ifndef nsCharTraits_h___
#include "nsCharTraits.h"
#endif
#ifndef nsStringTraits_h___
#include "nsStringTraits.h"
#endif
#ifndef nsAlgorithm_h___
#include "nsAlgorithm.h"
// for |NS_MIN|, |NS_MAX|, and |NS_COUNT|...
#endif
/**
*
* @see nsReadableFragment
* @see nsAString
* @status FROZEN
*/
template <class CharT>
class nsReadingIterator
// : public bidirectional_iterator_tag
{
public:
typedef ptrdiff_t difference_type;
typedef CharT value_type;
typedef const CharT* pointer;
typedef const CharT& reference;
// typedef bidirectional_iterator_tag iterator_category;
typedef nsReadableFragment<CharT> const_fragment_type;
typedef nsWritableFragment<CharT> fragment_type;
private:
friend class nsAString;
friend class nsACString;
typedef typename nsStringTraits<CharT>::abstract_string_type abstract_string_type;
const_fragment_type mFragment;
const CharT* mPosition;
const abstract_string_type* mOwningString;
public:
nsReadingIterator() { }
// nsReadingIterator( const nsReadingIterator<CharT>& ); // auto-generated copy-constructor OK
// nsReadingIterator<CharT>& operator=( const nsReadingIterator<CharT>& ); // auto-generated copy-assignment operator OK
inline void normalize_forward();
inline void normalize_backward();
pointer
get() const
{
return mPosition;
}
CharT
operator*() const
{
return *get();
}
#if 0
// An iterator really deserves this, but some compilers (notably IBM VisualAge for OS/2)
// don't like this when |CharT| is a type without members.
pointer
operator->() const
{
return get();
}
#endif
nsReadingIterator<CharT>&
operator++()
{
++mPosition;
normalize_forward();
return *this;
}
nsReadingIterator<CharT>
operator++( int )
{
nsReadingIterator<CharT> result(*this);
++mPosition;
normalize_forward();
return result;
}
nsReadingIterator<CharT>&
operator--()
{
normalize_backward();
--mPosition;
return *this;
}
nsReadingIterator<CharT>
operator--( int )
{
nsReadingIterator<CharT> result(*this);
normalize_backward();
--mPosition;
return result;
}
const const_fragment_type&
fragment() const
{
return mFragment;
}
const abstract_string_type&
string() const
{
NS_ASSERTION(mOwningString, "iterator not attached to a string (|mOwningString| == 0)");
return *mOwningString;
}
difference_type
size_forward() const
{
return mFragment.mEnd - mPosition;
}
difference_type
size_backward() const
{
return mPosition - mFragment.mStart;
}
nsReadingIterator<CharT>&
advance( difference_type n )
{
while ( n > 0 )
{
difference_type one_hop = NS_MIN(n, size_forward());
NS_ASSERTION(one_hop>0, "Infinite loop: can't advance a reading iterator beyond the end of a string");
// perhaps I should |break| if |!one_hop|?
mPosition += one_hop;
normalize_forward();
n -= one_hop;
}
while ( n < 0 )
{
normalize_backward();
difference_type one_hop = NS_MAX(n, -size_backward());
NS_ASSERTION(one_hop<0, "Infinite loop: can't advance (backward) a reading iterator beyond the end of a string");
// perhaps I should |break| if |!one_hop|?
mPosition += one_hop;
n -= one_hop;
}
return *this;
}
};
/**
*
* @see nsWritableFragment
* @see nsAString
* @status FROZEN
*/
template <class CharT>
class nsWritingIterator
// : public nsReadingIterator<CharT>
{
public:
typedef ptrdiff_t difference_type;
typedef CharT value_type;
typedef CharT* pointer;
typedef CharT& reference;
// typedef bidirectional_iterator_tag iterator_category;
typedef nsReadableFragment<CharT> const_fragment_type;
typedef nsWritableFragment<CharT> fragment_type;
private:
friend class nsAString;
friend class nsACString;
typedef typename nsStringTraits<CharT>::abstract_string_type abstract_string_type;
fragment_type mFragment;
CharT* mPosition;
abstract_string_type* mOwningString;
public:
nsWritingIterator() { }
// nsWritingIterator( const nsWritingIterator<CharT>& ); // auto-generated copy-constructor OK
// nsWritingIterator<CharT>& operator=( const nsWritingIterator<CharT>& ); // auto-generated copy-assignment operator OK
inline void normalize_forward();
inline void normalize_backward();
pointer
get() const
{
return mPosition;
}
reference
operator*() const
{
return *get();
}
#if 0
// An iterator really deserves this, but some compilers (notably IBM VisualAge for OS/2)
// don't like this when |CharT| is a type without members.
pointer
operator->() const
{
return get();
}
#endif
nsWritingIterator<CharT>&
operator++()
{
++mPosition;
normalize_forward();
return *this;
}
nsWritingIterator<CharT>
operator++( int )
{
nsWritingIterator<CharT> result(*this);
++mPosition;
normalize_forward();
return result;
}
nsWritingIterator<CharT>&
operator--()
{
normalize_backward();
--mPosition;
return *this;
}
nsWritingIterator<CharT>
operator--( int )
{
nsWritingIterator<CharT> result(*this);
normalize_backward();
--mPosition;
return result;
}
const fragment_type&
fragment() const
{
return mFragment;
}
fragment_type&
fragment()
{
return mFragment;
}
const abstract_string_type&
string() const
{
NS_ASSERTION(mOwningString, "iterator not attached to a string (|mOwningString| == 0)");
return *mOwningString;
}
abstract_string_type&
string()
{
NS_ASSERTION(mOwningString, "iterator not attached to a string (|mOwningString| == 0)");
return *mOwningString;
}
difference_type
size_forward() const
{
return mFragment.mEnd - mPosition;
}
difference_type
size_backward() const
{
return mPosition - mFragment.mStart;
}
nsWritingIterator<CharT>&
advance( difference_type n )
{
while ( n > 0 )
{
difference_type one_hop = NS_MIN(n, size_forward());
NS_ASSERTION(one_hop>0, "Infinite loop: can't advance a writing iterator beyond the end of a string");
// perhaps I should |break| if |!one_hop|?
mPosition += one_hop;
normalize_forward();
n -= one_hop;
}
while ( n < 0 )
{
normalize_backward();
difference_type one_hop = NS_MAX(n, -size_backward());
NS_ASSERTION(one_hop<0, "Infinite loop: can't advance (backward) a writing iterator beyond the end of a string");
// perhaps I should |break| if |!one_hop|?
mPosition += one_hop;
n -= one_hop;
}
return *this;
}
PRUint32
write( const value_type* s, PRUint32 n )
{
NS_ASSERTION(size_forward() > 0, "You can't |write| into an |nsWritingIterator| with no space!");
n = NS_MIN(n, PRUint32(size_forward()));
nsCharTraits<value_type>::move(mPosition, s, n);
advance( difference_type(n) );
return n;
}
};
template <class CharT>
inline
void
nsReadingIterator<CharT>::normalize_forward()
{
while ( mPosition == mFragment.mEnd
&& mOwningString->GetReadableFragment(mFragment, kNextFragment) )
mPosition = mFragment.mStart;
}
template <class CharT>
inline
void
nsReadingIterator<CharT>::normalize_backward()
{
while ( mPosition == mFragment.mStart
&& mOwningString->GetReadableFragment(mFragment, kPrevFragment) )
mPosition = mFragment.mEnd;
}
template <class CharT>
inline
PRBool
operator==( const nsReadingIterator<CharT>& lhs, const nsReadingIterator<CharT>& rhs )
{
return lhs.get() == rhs.get();
}
template <class CharT>
inline
PRBool
operator!=( const nsReadingIterator<CharT>& lhs, const nsReadingIterator<CharT>& rhs )
{
return lhs.get() != rhs.get();
}
//
// |nsWritingIterator|s
//
template <class CharT>
inline
void
nsWritingIterator<CharT>::normalize_forward()
{
while ( mPosition == mFragment.mEnd
&& mOwningString->GetWritableFragment(mFragment, kNextFragment) )
mPosition = mFragment.mStart;
}
template <class CharT>
inline
void
nsWritingIterator<CharT>::normalize_backward()
{
while ( mPosition == mFragment.mStart
&& mOwningString->GetWritableFragment(mFragment, kPrevFragment) )
mPosition = mFragment.mEnd;
}
template <class CharT>
inline
PRBool
operator==( const nsWritingIterator<CharT>& lhs, const nsWritingIterator<CharT>& rhs )
{
return lhs.get() == rhs.get();
}
template <class CharT>
inline
PRBool
operator!=( const nsWritingIterator<CharT>& lhs, const nsWritingIterator<CharT>& rhs )
{
return lhs.get() != rhs.get();
}
#endif /* !defined(nsStringIterator_h___) */