xpcom/glue/nsTPtrArray.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is C++ pointer array template.
  17  *
  18  * The Initial Developer of the Original Code is Mozilla Foundation.
  19  * Portions created by the Initial Developer are Copyright (C) 2006
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *  Jonas Sicking <jonas@sicking.cc>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either the GNU General Public License Version 2 or later (the "GPL"), or
  27  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
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  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39
  40 #ifndef nsTPtrArray_h__
  41 #define nsTPtrArray_h__
  42
  43 #include "nsTArray.h"
  44
  45 //
  46 // The templatized array class for storing pointers. The class is based on
  47 // nsTArray and has all the features of that class, in addition to an
  48 // implementation of SafeElementAt that returns null for out of bounds access
  49 //
  50 template<class E>
  51 class nsTPtrArray : public nsTArray<E*> {
  52   public:
  53     typedef nsTPtrArray<E> self_type;
  54     typedef nsTArray<E*> base_type;
  55     typedef typename base_type::size_type size_type;
  56     typedef typename base_type::elem_type elem_type;
  57     typedef typename base_type::index_type index_type;
  58
  59     //
  60     // Initialization methods
  61     //
  62
  63     nsTPtrArray() {}
  64
  65     // Initialize this array and pre-allocate some number of elements.
  66     explicit nsTPtrArray(size_type capacity) {
  67       this->SetCapacity(capacity);
  68     }
  69
  70     // The array's copy-constructor performs a 'deep' copy of the given array.
  71     // @param other  The array object to copy.
  72     nsTPtrArray(const self_type& other) {
  73       this->AppendElements(other);
  74     }
  75
  76     //
  77     // Accessor methods
  78     //
  79
  80     // Forward SafeElementAt to avoid shadowing (and warnings thereof)
  81     elem_type& SafeElementAt(index_type i, elem_type& def) {
  82       return base_type::SafeElementAt(i, def);
  83     }
  84     const elem_type& SafeElementAt(index_type i, const elem_type& def) const {
  85       return base_type::SafeElementAt(i, def);
  86     }
  87
  88     // This method provides direct access to the i'th element of the array in
  89     // a bounds safe manner. If the requested index is out of bounds null is
  90     // returned.
  91     // @param i  The index of an element in the array.
  92     elem_type SafeElementAt(index_type i) const {
  93       return SafeElementAt(i, nsnull);
  94     }
  95 };
  96
  97 template<class E, PRUint32 N>
  98 class nsAutoTPtrArray : public nsTPtrArray<E> {
  99   public:
 100     typedef nsTPtrArray<E> base_type;
 101     typedef typename base_type::Header Header;
 102     typedef typename base_type::elem_type elem_type;
 103
 104     nsAutoTPtrArray() {
 105       base_type::mHdr = reinterpret_cast<Header*>(&mAutoBuf);
 106       base_type::mHdr->mLength = 0;
 107       base_type::mHdr->mCapacity = N;
 108       base_type::mHdr->mIsAutoArray = 1;
 109
 110       NS_ASSERTION(base_type::GetAutoArrayBuffer() ==
 111                    reinterpret_cast<Header*>(&mAutoBuf),
 112                    "GetAutoArrayBuffer needs to be fixed");
 113     }
 114
 115   protected:
 116     union {
 117       char mAutoBuf[sizeof(Header) + N * sizeof(elem_type)];
 118       PRUint64 dummy;
 119     };
 120 };
 121
 122 #endif  // nsTPtrArray_h__