page432.html
来自「wqeqwvrw rkjqhwrjwq jkhrjqwhrwq jkhrwq」· HTML 代码 · 共 61 行
HTML
61 行
<HTML>
<HEAD>
<TITLE>Implementation</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF">
<img src="cover75.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cover75.gif" alt="Logo" align=right>
<b>Data Structures and Algorithms
with Object-Oriented Design Patterns in C++</b><br>
<A NAME="tex2html7256" HREF="page433.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page433.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="next_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/next_motif.gif"></A> <A NAME="tex2html7254" HREF="page431.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page431.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="up_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/up_motif.gif"></A> <A NAME="tex2html7250" HREF="page431.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page431.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/previous_motif.gif"></A> <A NAME="tex2html7258" HREF="page9.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page9.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/contents_motif.gif"></A> <A NAME="tex2html7259" HREF="page620.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page620.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="index_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/index_motif.gif"></A> <BR><HR>
<H2><A NAME="SECTION0014410000000000000000">Implementation</A></H2>
<P>
The class <tt>BuddyPool</tt> is declared in Program <A HREF="page432.html#progpool4h" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page432.html#progpool4h"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cross_ref_motif.gif"></A>.
<tt>BuddyPool</tt> is a concrete class derived from the
abstract base class <tt>StoragePool</tt>.
The public interface includes a constructor, a destructor,
and the member functions <tt>Acquire</tt> and <tt>Release</tt>.
Three additional private member functions,
<tt>Buddy</tt>, <tt>Unlink</tt> and <tt>InsertAfter</tt> are declared.
<P>
<P><A NAME="32212"> </A><A NAME="progpool4h"> </A> <IMG WIDTH=575 HEIGHT=753 ALIGN=BOTTOM ALT="program31910" SRC="img1777.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/img1777.gif" ><BR>
<STRONG>Program:</STRONG> <tt>BuddyPool</tt> Class Definition<BR>
<P>
<P>
The nested structures <tt>Header</tt> and <tt>Block</tt>
implement the layout given in Figure <A HREF="page431.html#figblock3" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page431.html#figblock3"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cross_ref_motif.gif"></A>.
The <tt>Header</tt> contains fields which are used in the representation
of both <tt>reserved</tt> and <tt>free</tt> areas.
A <tt>Header</tt> comprises the two members <tt>status</tt> and <tt>k</tt>.
The former is a one-bit field of type <tt>Status</tt>.
The latter encodes the length of the block as described above.
<P>
The <tt>Block</tt> structure contains a <tt>union</tt>
that overlays an instance of the structure <tt>Links</tt>
with the <tt>userPart</tt> of the block.
If the block is a free block,
the contents of the <tt>Links</tt> structure are used to link the associated
area in the appropriate free list.
If the block is reserved,
the space in the <tt>userPart</tt> has been allocated to the user.
<P>
The minimum size of a block is the same
as for the <tt>DoublyLinkedPool</tt> class, viz.,
<P> <IMG WIDTH=387 HEIGHT=16 ALIGN=BOTTOM ALT="displaymath68239" SRC="img1778.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/img1778.gif" ><P>
which on a 32-bit machine is typically 12 bytes.
In the <tt>BuddyPool</tt> implementation given in Program <A HREF="page432.html#progpool4h" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page432.html#progpool4h"><IMG ALIGN=BOTTOM ALT="gif" SRC="cross_ref_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/cross_ref_motif.gif"></A>,
the size of the <tt>Block</tt> structure is set to 16 bytes.
<P>
<BR> <HR>
<UL>
<LI> <A NAME="tex2html7260" HREF="page433.html#SECTION0014411000000000000000" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page433.html#SECTION0014411000000000000000">Constructor and Destructor</A>
<LI> <A NAME="tex2html7261" HREF="page434.html#SECTION0014412000000000000000" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page434.html#SECTION0014412000000000000000">Acquiring an Area</A>
<LI> <A NAME="tex2html7262" HREF="page435.html#SECTION0014413000000000000000" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page435.html#SECTION0014413000000000000000">Releasing an Area</A>
</UL>
<HR><A NAME="tex2html7256" HREF="page433.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page433.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="next_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/next_motif.gif"></A> <A NAME="tex2html7254" HREF="page431.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page431.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="up_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/up_motif.gif"></A> <A NAME="tex2html7250" HREF="page431.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page431.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/previous_motif.gif"></A> <A NAME="tex2html7258" HREF="page9.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page9.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/contents_motif.gif"></A> <A NAME="tex2html7259" HREF="page620.html" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page620.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="index_motif.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/index_motif.gif"></A> <P><ADDRESS>
<img src="bruno.gif" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/icons/bruno.gif" alt="Bruno" align=right>
<a href="javascript:if(confirm('http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html \n\nThis file was not retrieved by Teleport Pro, because it is addressed on a domain or path outside the boundaries set for its Starting Address. \n\nDo you want to open it from the server?'))window.location='http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html'" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/copyright.html">Copyright © 1997</a> by <a href="javascript:if(confirm('http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html \n\nThis file was not retrieved by Teleport Pro, because it is addressed on a domain or path outside the boundaries set for its Starting Address. \n\nDo you want to open it from the server?'))window.location='http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html'" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/signature.html">Bruno R. Preiss, P.Eng.</a> All rights reserved.
</ADDRESS>
</BODY>
</HTML>
⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?