pjs/xpcom/string/public/nsStringIterator.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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 the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Scott Collins <scc@mozilla.org> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef nsStringIterator_h___
#define nsStringIterator_h___
#ifndef nsCharTraits_h___
#include "nsCharTraits.h"
#endif
#ifndef nsAlgorithm_h___
#include "nsAlgorithm.h"
#endif
#ifndef nsDebug_h___
#include "nsDebug.h"
#endif
/**
* @see nsTAString
*/
template <class CharT>
class nsReadingIterator
{
public:
typedef nsReadingIterator<CharT> self_type;
typedef ptrdiff_t difference_type;
typedef CharT value_type;
typedef const CharT* pointer;
typedef const CharT& reference;
private:
friend class nsAString;
friend class nsACString;
// unfortunately, the API for nsReadingIterator requires that the
// iterator know its start and end positions. this was needed when
// we supported multi-fragment strings, but now it is really just
// extra baggage. we should remove mStart and mEnd at some point.
const CharT* mStart;
const CharT* mEnd;
const CharT* mPosition;
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
start() const
{
return mStart;
}
pointer
end() const
{
return mEnd;
}
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
self_type&
operator++()
{
++mPosition;
return *this;
}
self_type
operator++( int )
{
self_type result(*this);
++mPosition;
return result;
}
self_type&
operator--()
{
--mPosition;
return *this;
}
self_type
operator--( int )
{
self_type result(*this);
--mPosition;
return result;
}
difference_type
size_forward() const
{
return mEnd - mPosition;
}
difference_type
size_backward() const
{
return mPosition - mStart;
}
self_type&
advance( difference_type n )
{
if (n > 0)
{
difference_type step = NS_MIN(n, size_forward());
NS_ASSERTION(step>0, "can't advance a reading iterator beyond the end of a string");
mPosition += step;
}
else if (n < 0)
{
difference_type step = NS_MAX(n, -size_backward());
NS_ASSERTION(step<0, "can't advance (backward) a reading iterator beyond the end of a string");
mPosition += step;
}
return *this;
}
};
/**
* @see nsTAString
*/
template <class CharT>
class nsWritingIterator
{
public:
typedef nsWritingIterator<CharT> self_type;
typedef ptrdiff_t difference_type;
typedef CharT value_type;
typedef CharT* pointer;
typedef CharT& reference;
private:
friend class nsAString;
friend class nsACString;
// unfortunately, the API for nsWritingIterator requires that the
// iterator know its start and end positions. this was needed when
// we supported multi-fragment strings, but now it is really just
// extra baggage. we should remove mStart and mEnd at some point.
CharT* mStart;
CharT* mEnd;
CharT* mPosition;
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
start() const
{
return mStart;
}
pointer
end() const
{
return mEnd;
}
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
self_type&
operator++()
{
++mPosition;
return *this;
}
self_type
operator++( int )
{
self_type result(*this);
++mPosition;
return result;
}
self_type&
operator--()
{
--mPosition;
return *this;
}
self_type
operator--( int )
{
self_type result(*this);
--mPosition;
return result;
}
difference_type
size_forward() const
{
return mEnd - mPosition;
}
difference_type
size_backward() const
{
return mPosition - mStart;
}
self_type&
advance( difference_type n )
{
if (n > 0)
{
difference_type step = NS_MIN(n, size_forward());
NS_ASSERTION(step>0, "can't advance a writing iterator beyond the end of a string");
mPosition += step;
}
else if (n < 0)
{
difference_type step = NS_MAX(n, -size_backward());
NS_ASSERTION(step<0, "can't advance (backward) a writing iterator beyond the end of a string");
mPosition += step;
}
return *this;
}
void
write( const value_type* s, PRUint32 n )
{
NS_ASSERTION(size_forward() > 0, "You can't |write| into an |nsWritingIterator| with no space!");
nsCharTraits<value_type>::move(mPosition, s, n);
advance( difference_type(n) );
}
};
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
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___) */