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| <Head> |
| <Title>Buffer</Title> |
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| <h3>Buffer Concept</h3> |
| |
| A Buffer is something in which items can be put and removed. |
| The Buffer <i>concept</i> has very few requirements. It does |
| not require any particular ordering of how the items are stored or in |
| what order they will appear when removed, however, there is typically |
| some sort of ordering policy. |
| |
| <h3>Notation</h3> |
| |
| <table> |
| <tr> <td> <tt>B</tt> </td> <td> is a type that models Buffer. </td></tr> |
| <tr> <td> <tt>T</tt> </td> <td> is the value type of <tt>B</tt>. </td></tr> |
| <tr> <td> <tt>t</tt> </td> <td> is an object of type <tt>T</tt>. </td></tr> |
| </table> |
| |
| |
| <h3>Members</h3> |
| |
| For a type to model the Buffer concept it must have the following members. |
| |
| <p> |
| |
| <table border="1"> |
| |
| <tr> <td><b>Member</b></td> <td><b>Description</b></td> </tr> |
| |
| <tr> <td> <tt>value_type</tt> </td> |
| <td> The type of object stored in the Buffer. The value type |
| must be <A href="http://www.sgi.com/tech/stl/Assignable.html">Assignable</a>.</td> |
| </tr> |
| |
| <tr> <td> <tt>size_type</tt> </td> |
| <td> An unsigned integral type for representing the number of |
| objects in the Buffer.</td> |
| </tr> |
| |
| <tr> <td> <tt>void push(const T& t)</tt> </td> |
| <td> Inserts <tt>t</tt> into the Buffer. <tt>size()</tt> will be |
| incremented by one.</td> |
| </tr> |
| |
| <tr> <td> <tt>void pop()</tt> </td> |
| <td> Removes an object from the Buffer. <tt>size()</tt> will be |
| decremented by one. Precondition: <tt>empty()</tt> |
| is <tt>false</tt>. </td> |
| </tr> |
| |
| <tr> <td> <tt>T& top()</tt> </td> |
| <td> Returns a mutable reference to some object in the Buffer. |
| Precondition: <tt>empty()</tt> is <tt>false</tt>.</td> |
| </tr> |
| |
| <tr> <td> <tt>const T& top() const</tt> </td> |
| <td> Returns a const reference to some object in the Buffer. |
| Precondition: <tt>empty()</tt> is <tt>false</tt>.</td> |
| </tr> |
| |
| <tr> <td> <tt>size_type size() const</tt> </td> |
| <td> Returns the number of objects in the Buffer. |
| Invariant: <tt>size() >= 0</tt>. </td> |
| </tr> |
| |
| <tr> <td> <tt>bool empty() const</tt> </td> |
| <td> Equivalent to <tt>b.size() == 0</tt>.</td> |
| </tr> |
| |
| </table> |
| |
| <h3>Complexity Guarantees</h3> |
| |
| <UL> |
| |
| <LI> <tt>push()</tt>, <tt>pop()</tt>, and <tt>size()</tt> must be at |
| most linear time complexity in the size of the Generalized Queue. |
| |
| <LI> <tt>top()</tt> and <tt>empty()</tt> must be amortized constant time. |
| |
| </UL> |
| |
| <h3>Models</h3> |
| |
| <UL> |
| <LI><a href="http://www.sgi.com/tech/stl/stack.html"><tt>std::stack</tt></a> |
| <LI><a href="../../../boost/pending/mutable_queue.hpp"><tt>boost::mutable_queue</tt></a> |
| </UL> |
| |
| <p> |
| |
| <br> |
| <HR> |
| <TABLE> |
| <TR valign=top> |
| <TD nowrap>Copyright © 2000-2001</TD><TD> |
| <A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>, Indiana University and C++ Library & Compiler Group/SGI (<A HREF="mailto:jsiek@engr.sgi.com">jsiek@engr.sgi.com</A>) |
| </TD></TR></TABLE> |
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