michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsStringIterator_h___
michael@0: #define nsStringIterator_h___
michael@0: 
michael@0: #include "nsCharTraits.h"
michael@0: #include "nsAlgorithm.h"
michael@0: #include "nsDebug.h"
michael@0: 
michael@0:   /**
michael@0:    * @see nsTAString
michael@0:    */
michael@0: 
michael@0: template <class CharT>
michael@0: class nsReadingIterator
michael@0:   {
michael@0:     public:
michael@0:       typedef nsReadingIterator<CharT>    self_type;
michael@0:       typedef ptrdiff_t                   difference_type;
michael@0:       typedef CharT                       value_type;
michael@0:       typedef const CharT*                pointer;
michael@0:       typedef const CharT&                reference;
michael@0: 
michael@0:     private:
michael@0:       friend class nsAString;
michael@0:       friend class nsACString;
michael@0: 
michael@0:         // unfortunately, the API for nsReadingIterator requires that the
michael@0:         // iterator know its start and end positions.  this was needed when
michael@0:         // we supported multi-fragment strings, but now it is really just
michael@0:         // extra baggage.  we should remove mStart and mEnd at some point.
michael@0: 
michael@0:       const CharT* mStart;
michael@0:       const CharT* mEnd;
michael@0:       const CharT* mPosition;
michael@0: 
michael@0:     public:
michael@0:       nsReadingIterator() { }
michael@0:       // nsReadingIterator( const nsReadingIterator<CharT>& );                    // auto-generated copy-constructor OK
michael@0:       // nsReadingIterator<CharT>& operator=( const nsReadingIterator<CharT>& );  // auto-generated copy-assignment operator OK
michael@0: 
michael@0:       inline void normalize_forward() {}
michael@0:       inline void normalize_backward() {}
michael@0: 
michael@0:       pointer
michael@0:       start() const
michael@0:         {
michael@0:           return mStart;
michael@0:         }
michael@0: 
michael@0:       pointer
michael@0:       end() const
michael@0:         {
michael@0:           return mEnd;
michael@0:         }
michael@0: 
michael@0:       pointer
michael@0:       get() const
michael@0:         {
michael@0:           return mPosition;
michael@0:         }
michael@0:       
michael@0:       CharT
michael@0:       operator*() const
michael@0:         {
michael@0:           return *get();
michael@0:         }
michael@0: 
michael@0: #if 0
michael@0:         // An iterator really deserves this, but some compilers (notably IBM VisualAge for OS/2)
michael@0:         //  don't like this when |CharT| is a type without members.
michael@0:       pointer
michael@0:       operator->() const
michael@0:         {
michael@0:           return get();
michael@0:         }
michael@0: #endif
michael@0: 
michael@0:       self_type&
michael@0:       operator++()
michael@0:         {
michael@0:           ++mPosition;
michael@0:           return *this;
michael@0:         }
michael@0: 
michael@0:       self_type
michael@0:       operator++( int )
michael@0:         {
michael@0:           self_type result(*this);
michael@0:           ++mPosition;
michael@0:           return result;
michael@0:         }
michael@0: 
michael@0:       self_type&
michael@0:       operator--()
michael@0:         {
michael@0:           --mPosition;
michael@0:           return *this;
michael@0:         }
michael@0: 
michael@0:       self_type
michael@0:       operator--( int )
michael@0:         {
michael@0:           self_type result(*this);
michael@0:           --mPosition;
michael@0:           return result;
michael@0:         }
michael@0: 
michael@0:       difference_type
michael@0:       size_forward() const
michael@0:         {
michael@0:           return mEnd - mPosition;
michael@0:         }
michael@0: 
michael@0:       difference_type
michael@0:       size_backward() const
michael@0:         {
michael@0:           return mPosition - mStart;
michael@0:         }
michael@0: 
michael@0:       self_type&
michael@0:       advance( difference_type n )
michael@0:         {
michael@0:           if (n > 0)
michael@0:             {
michael@0:               difference_type step = XPCOM_MIN(n, size_forward());
michael@0: 
michael@0:               NS_ASSERTION(step>0, "can't advance a reading iterator beyond the end of a string");
michael@0: 
michael@0:               mPosition += step;
michael@0:             }
michael@0:           else if (n < 0)
michael@0:             {
michael@0:               difference_type step = XPCOM_MAX(n, -size_backward());
michael@0: 
michael@0:               NS_ASSERTION(step<0, "can't advance (backward) a reading iterator beyond the end of a string");
michael@0: 
michael@0:               mPosition += step;
michael@0:             }
michael@0:           return *this;
michael@0:         }
michael@0:   };
michael@0: 
michael@0:   /**
michael@0:    * @see nsTAString
michael@0:    */
michael@0: 
michael@0: template <class CharT>
michael@0: class nsWritingIterator
michael@0:   {
michael@0:     public:
michael@0:       typedef nsWritingIterator<CharT>   self_type;
michael@0:       typedef ptrdiff_t                  difference_type;
michael@0:       typedef CharT                      value_type;
michael@0:       typedef CharT*                     pointer;
michael@0:       typedef CharT&                     reference;
michael@0: 
michael@0:     private:
michael@0:       friend class nsAString;
michael@0:       friend class nsACString;
michael@0: 
michael@0:         // unfortunately, the API for nsWritingIterator requires that the
michael@0:         // iterator know its start and end positions.  this was needed when
michael@0:         // we supported multi-fragment strings, but now it is really just
michael@0:         // extra baggage.  we should remove mStart and mEnd at some point.
michael@0: 
michael@0:       CharT* mStart;
michael@0:       CharT* mEnd;
michael@0:       CharT* mPosition;
michael@0: 
michael@0:     public:
michael@0:       nsWritingIterator() { }
michael@0:       // nsWritingIterator( const nsWritingIterator<CharT>& );                    // auto-generated copy-constructor OK
michael@0:       // nsWritingIterator<CharT>& operator=( const nsWritingIterator<CharT>& );  // auto-generated copy-assignment operator OK
michael@0: 
michael@0:       inline void normalize_forward() {}
michael@0:       inline void normalize_backward() {}
michael@0: 
michael@0:       pointer
michael@0:       start() const
michael@0:         {
michael@0:           return mStart;
michael@0:         }
michael@0: 
michael@0:       pointer
michael@0:       end() const
michael@0:         {
michael@0:           return mEnd;
michael@0:         }
michael@0: 
michael@0:       pointer
michael@0:       get() const
michael@0:         {
michael@0:           return mPosition;
michael@0:         }
michael@0:       
michael@0:       reference
michael@0:       operator*() const
michael@0:         {
michael@0:           return *get();
michael@0:         }
michael@0: 
michael@0: #if 0
michael@0:         // An iterator really deserves this, but some compilers (notably IBM VisualAge for OS/2)
michael@0:         //  don't like this when |CharT| is a type without members.
michael@0:       pointer
michael@0:       operator->() const
michael@0:         {
michael@0:           return get();
michael@0:         }
michael@0: #endif
michael@0: 
michael@0:       self_type&
michael@0:       operator++()
michael@0:         {
michael@0:           ++mPosition;
michael@0:           return *this;
michael@0:         }
michael@0: 
michael@0:       self_type
michael@0:       operator++( int )
michael@0:         {
michael@0:           self_type result(*this);
michael@0:           ++mPosition;
michael@0:           return result;
michael@0:         }
michael@0: 
michael@0:       self_type&
michael@0:       operator--()
michael@0:         {
michael@0:           --mPosition;
michael@0:           return *this;
michael@0:         }
michael@0: 
michael@0:       self_type
michael@0:       operator--( int )
michael@0:         {
michael@0:           self_type result(*this);
michael@0:           --mPosition;
michael@0:           return result;
michael@0:         }
michael@0: 
michael@0:       difference_type
michael@0:       size_forward() const
michael@0:         {
michael@0:           return mEnd - mPosition;
michael@0:         }
michael@0: 
michael@0:       difference_type
michael@0:       size_backward() const
michael@0:         {
michael@0:           return mPosition - mStart;
michael@0:         }
michael@0: 
michael@0:       self_type&
michael@0:       advance( difference_type n )
michael@0:         {
michael@0:           if (n > 0)
michael@0:             {
michael@0:               difference_type step = XPCOM_MIN(n, size_forward());
michael@0: 
michael@0:               NS_ASSERTION(step>0, "can't advance a writing iterator beyond the end of a string");
michael@0: 
michael@0:               mPosition += step;
michael@0:             }
michael@0:           else if (n < 0)
michael@0:             {
michael@0:               difference_type step = XPCOM_MAX(n, -size_backward());
michael@0: 
michael@0:               NS_ASSERTION(step<0, "can't advance (backward) a writing iterator beyond the end of a string");
michael@0: 
michael@0:               mPosition += step;
michael@0:             }
michael@0:           return *this;
michael@0:         }
michael@0: 
michael@0:       void
michael@0:       write( const value_type* s, uint32_t n )
michael@0:         {
michael@0:           NS_ASSERTION(size_forward() > 0, "You can't |write| into an |nsWritingIterator| with no space!");
michael@0: 
michael@0:           nsCharTraits<value_type>::move(mPosition, s, n);
michael@0:           advance( difference_type(n) );
michael@0:         }
michael@0:   };
michael@0: 
michael@0: template <class CharT>
michael@0: inline
michael@0: bool
michael@0: operator==( const nsReadingIterator<CharT>& lhs, const nsReadingIterator<CharT>& rhs )
michael@0:   {
michael@0:     return lhs.get() == rhs.get();
michael@0:   }
michael@0: 
michael@0: template <class CharT>
michael@0: inline
michael@0: bool
michael@0: operator!=( const nsReadingIterator<CharT>& lhs, const nsReadingIterator<CharT>& rhs )
michael@0:   {
michael@0:     return lhs.get() != rhs.get();
michael@0:   }
michael@0: 
michael@0: 
michael@0:   //
michael@0:   // |nsWritingIterator|s
michael@0:   //
michael@0: 
michael@0: template <class CharT>
michael@0: inline
michael@0: bool
michael@0: operator==( const nsWritingIterator<CharT>& lhs, const nsWritingIterator<CharT>& rhs )
michael@0:   {
michael@0:     return lhs.get() == rhs.get();
michael@0:   }
michael@0: 
michael@0: template <class CharT>
michael@0: inline
michael@0: bool
michael@0: operator!=( const nsWritingIterator<CharT>& lhs, const nsWritingIterator<CharT>& rhs )
michael@0:   {
michael@0:     return lhs.get() != rhs.get();
michael@0:   }
michael@0: 
michael@0: #endif /* !defined(nsStringIterator_h___) */