gecko-dev/string/public/nsStringFragment.h

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/* -*- 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)
*/
/* nsStringFragment.h --- machinery that makes string iterators work */
#ifndef nsStringFragment_h___
#define nsStringFragment_h___
#ifndef nsStringDefines_h___
#include "nsStringDefines.h"
#endif
/**
* An |nsFragmentRequest| is used to tell |GetReadableFragment| and
* |GetWritableFragment| what to do.
*
* @see GetReadableFragment
*/
enum nsFragmentRequest { kPrevFragment, kFirstFragment, kLastFragment, kNextFragment, kFragmentAt };
/**
* A |nsReadableFragment| provides |const| access to a contiguous hunk of
* string of homogenous units, e.g., bytes (|char|). This doesn't mean it
* represents a flat hunk. It could be a variable length encoding, for
* instance UTF-8. And the fragment itself need not be zero-terminated.
*
* An |nsReadableFragment| is the underlying machinery that lets
* |nsReadingIterator|s work.
*
* @see nsReadingIterator
* @status FROZEN
*/
template <class CharT>
struct nsReadableFragment
{
const CharT* mStart;
const CharT* mEnd;
const void* mFragmentIdentifier;
nsReadableFragment()
: mStart(0), mEnd(0), mFragmentIdentifier(0)
{
// nothing else to do here
}
const void*
GetID() const
{
return mFragmentIdentifier;
}
unsigned long
GetIDAsInt() const
{
typedef char* char_ptr;
typedef unsigned long ulong;
return ulong(char_ptr(mFragmentIdentifier)-char_ptr(0));
}
void
SetID( const void* aID )
{
mFragmentIdentifier = aID;
}
void
SetID( unsigned long aID )
{
typedef char* char_ptr;
typedef void* void_ptr;
mFragmentIdentifier = void_ptr(char_ptr(0)+aID);
}
};
/**
* A |nsWritableFragment| provides non-|const| access to a contiguous hunk of
* string of homogenous units, e.g., bytes (|char|). This doesn't mean it
* represents a flat hunk. It could be a variable length encoding, for
* instance UTF-8. And the fragment itself need not be zero-terminated.
*
* An |nsWritableFragment| is the underlying machinery that lets
* |nsWritingIterator|s work.
*
* @see nsWritingIterator
* @status FROZEN
*/
template <class CharT>
struct nsWritableFragment
{
CharT* mStart;
CharT* mEnd;
void* mFragmentIdentifier;
nsWritableFragment()
: mStart(0), mEnd(0), mFragmentIdentifier(0)
{
// nothing else to do here
}
};
#endif /* !defined(nsStringFragment_h___) */