lists.tobjlist.html
来自「PTypes是一个扩充了多线程和网络功能的STL库」· HTML 代码 · 共 108 行
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<html><!-- #BeginTemplate "/Templates/tmpl.dwt" --><!-- DW6 --><head><!-- #BeginEditable "doctitle" --> <title>PTypes: lists: tobjlist</title><!-- #EndEditable --> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link rel="stylesheet" href="styles.css"></head><body bgcolor="#FFFFFF" leftmargin="40" marginwidth="40"><p><a href="../index.html"><img src="title-20.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.0" border="0"></a> <hr size="1" noshade><!-- #BeginEditable "body" --> <p class="hpath"><a href="index.html">Top</a>: <a href="basic.html">Basic types</a>: <a href="lists.html">Lists</a>: tobjlist</p><blockquote> <pre class="lang">template <class X> class tobjlist { tobjlist(bool ownobjects = false); ~tobjlist(); int get/set_count(int); int get/set_capacity(int); bool get/set_ownobjects(bool); void ins(int index, X* obj); void add(X* obj); X* operator [](int index) const; X* top() const; void put(int index, X* obj); void del(int index); X* pop(); void clear(); void pack(); bool search(const void* key, int& index) const; virtual int compare(const void* key, const void* obj) const;}</pre></blockquote><p><br>The <span class="lang">tobjlist</span> template implements a dynamic array of pointers to objects of an arbitrary type <span class="lang">X</span>. Since the list itself only holds pointers to objects, the element type can be any structure, including a class with constructors and destructors. The element type is not required to have a copy constructor. A list can contain objects of any derivative class of <span class="lang">X</span> as well.</p><p><span class="lang">Tobjlist</span> can optionally (with <span class="lang">ownobjects</span> = <span class="lang">true</span>) be responsible for freeing objects whenever they are removed from a list, in which case the objects are required to be dynamically allocated with operator <span class="lang">new</span>. Objects can be automatically freed by the following methods: <span class="lang">set_count()</span> if the new value is less than the old one, also <span class="lang">del()</span>, <span class="lang">clear()</span>, <span class="lang">put()</span> and <span class="lang">~tobjlist()</span>.</p><p><span class="def">tobjlist::tobjlist(bool ownobjects = false)</span> constructs a <span class="lang">tobjlist</span> object. See note for the parameter <span class="lang">ownobjects</span> above.</p><p><span class="def">tobjlist::~tobjlist()</span> calls <span class="lang">clear()</span> and destroys the list object.</p><p><span class="def">int tobjlist::get/set_count(int)</span> gets or sets the number of items in a list. If the new value for <span class="lang">count</span> is greater than the old one, all new slots are filled with NULL pointers. If it's smaller and if <span class="lang">ownobjects</span> is true, extra objects are freed.</p><p><span class="def">int tobjlist::get/set_capacity(int)</span> gets or sets the capacity of a list. The <span class="lang">capacity</span> property reflects the number of slots actually allocated for a list and is set automatically by other methods whenever necessary. Like <span class="lang">tpodlist</span>, <span class="lang">tobjlist</span> uses a 'lazy allocation' technique (see also <a href="lists.tpodlist.html">tpodlist::get/set_capacity</a>).</p><p><span class="def">bool tobjlist::get/set_ownobjects(bool)</span> returns or sets the <span class="lang">ownobjects</span> flag.</p><p><span class="def">void tobjlist::ins(int index, X* obj)</span> inserts the object <span class="lang">obj</span> into a list at the position <span class="lang">index</span>. All pointers with greater indexes are moved up to make room for the new pointer.</p><p><span class="def">void tobjlist::add(X* obj)</span> adds the object <span class="lang">obj</span> to the end of a list.</p><p><span class="def">X* tobjlist::operator [](int index)</span> returns the pointer to an object at the position <span class="lang">index</span>. </p><p><span class="def">X* tobjlist::top()</span> returns the last pointer in a list.</p><p><span class="def">void tobjlist::put(int index, X* obj)</span> replaces the pointer at the position <span class="lang">index</span> with <span class="lang">obj</span>. Can free the old object if <span class="lang">ownobjects</span> is <span class="lang">true</span>.</p><p><span class="def">void tobjlist::del(int index)</span> deletes the pointer at the position <span class="lang">index</span> and moves all pointers with greater indexes down. Can also free the object if <span class="lang">ownobjects</span> is <span class="lang">true</span>.</p><p><span class="def">X* tobjlist::pop()</span> returns the last pointer in a list and deletes it from a list.</p><p><span class="def">void tobjlist::clear()</span> deletes all pointers from a list. Can also free all objects if <span class="lang">ownobjects</span> is <span class="lang">true</span>.</p><p><span class="def">void tobjlist::pack()</span> sets <span class="lang">capacity</span> equal to <span class="lang">count</span>. You can call <span class="lang">pack()</span> after deleting multiple pointers from a list to optimize memory usage.</p><p><span class="def">bool tobjlist::search(const void* key, int& index)</span> performs binary search on a list. The virtual method <span class="lang">compare()</span> (below) must be overridden in order for <span class="lang">search()</span> to work.</p><p><span class="def">virtual int tobjlist::compare(const void* key, const void* obj)</span> override this method in a descendant class to be able to perform binary search on a list. The value of <span class="lang">key</span> is the same as in the call to <span class="lang">search()</span>. <span class="lang">Obj</span> is a pointer to an object that must be compared against <span class="lang">key</span>. The return value must be -1, 0 or 1, similarly to the function <span class="lang">strcmp()</span>.</p><p class="seealso">See also: <a href="lists.tpodlist.html">tpodlist</a>, <a href="lists.tstrlist.html">tstrlist</a></p><!-- #EndEditable --><hr size="1"><a href="../index.html" class="ns">PTypes home</a></body><!-- #EndTemplate --></html>⌨️ 快捷键说明
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