Commit | Line | Data |
---|---|---|
920dae64 AT |
1 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> |
2 | <html> | |
3 | <head> | |
4 | <link rel="STYLESHEET" href="lib.css" type='text/css' /> | |
5 | <link rel="SHORTCUT ICON" href="../icons/pyfav.png" type="image/png" /> | |
6 | <link rel='start' href='../index.html' title='Python Documentation Index' /> | |
7 | <link rel="first" href="lib.html" title='Python Library Reference' /> | |
8 | <link rel='contents' href='contents.html' title="Contents" /> | |
9 | <link rel='index' href='genindex.html' title='Index' /> | |
10 | <link rel='last' href='about.html' title='About this document...' /> | |
11 | <link rel='help' href='about.html' title='About this document...' /> | |
12 | <link rel="next" href="xdr-unpacker-objects.html" /> | |
13 | <link rel="prev" href="module-xdrlib.html" /> | |
14 | <link rel="parent" href="module-xdrlib.html" /> | |
15 | <link rel="next" href="xdr-unpacker-objects.html" /> | |
16 | <meta name='aesop' content='information' /> | |
17 | <title>12.17.1 Packer Objects </title> | |
18 | </head> | |
19 | <body> | |
20 | <DIV CLASS="navigation"> | |
21 | <div id='top-navigation-panel' xml:id='top-navigation-panel'> | |
22 | <table align="center" width="100%" cellpadding="0" cellspacing="2"> | |
23 | <tr> | |
24 | <td class='online-navigation'><a rel="prev" title="12.17 xdrlib " | |
25 | href="module-xdrlib.html"><img src='../icons/previous.png' | |
26 | border='0' height='32' alt='Previous Page' width='32' /></A></td> | |
27 | <td class='online-navigation'><a rel="parent" title="12.17 xdrlib " | |
28 | href="module-xdrlib.html"><img src='../icons/up.png' | |
29 | border='0' height='32' alt='Up One Level' width='32' /></A></td> | |
30 | <td class='online-navigation'><a rel="next" title="12.17.2 Unpacker Objects" | |
31 | href="xdr-unpacker-objects.html"><img src='../icons/next.png' | |
32 | border='0' height='32' alt='Next Page' width='32' /></A></td> | |
33 | <td align="center" width="100%">Python Library Reference</td> | |
34 | <td class='online-navigation'><a rel="contents" title="Table of Contents" | |
35 | href="contents.html"><img src='../icons/contents.png' | |
36 | border='0' height='32' alt='Contents' width='32' /></A></td> | |
37 | <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' | |
38 | border='0' height='32' alt='Module Index' width='32' /></a></td> | |
39 | <td class='online-navigation'><a rel="index" title="Index" | |
40 | href="genindex.html"><img src='../icons/index.png' | |
41 | border='0' height='32' alt='Index' width='32' /></A></td> | |
42 | </tr></table> | |
43 | <div class='online-navigation'> | |
44 | <b class="navlabel">Previous:</b> | |
45 | <a class="sectref" rel="prev" href="module-xdrlib.html">12.17 xdrlib </A> | |
46 | <b class="navlabel">Up:</b> | |
47 | <a class="sectref" rel="parent" href="module-xdrlib.html">12.17 xdrlib </A> | |
48 | <b class="navlabel">Next:</b> | |
49 | <a class="sectref" rel="next" href="xdr-unpacker-objects.html">12.17.2 Unpacker Objects</A> | |
50 | </div> | |
51 | <hr /></div> | |
52 | </DIV> | |
53 | <!--End of Navigation Panel--> | |
54 | ||
55 | <H2><A NAME="SECTION00141710000000000000000"></A><A NAME="xdr-packer-objects"></A> | |
56 | <BR> | |
57 | 12.17.1 Packer Objects | |
58 | </H2> | |
59 | ||
60 | <P> | |
61 | <tt class="class">Packer</tt> instances have the following methods: | |
62 | ||
63 | <P> | |
64 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
65 | <td><nobr><b><tt id='l2h-4165' xml:id='l2h-4165' class="method">get_buffer</tt></b>(</nobr></td> | |
66 | <td><var></var>)</td></tr></table></dt> | |
67 | <dd> | |
68 | Returns the current pack buffer as a string. | |
69 | </dl> | |
70 | ||
71 | <P> | |
72 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
73 | <td><nobr><b><tt id='l2h-4166' xml:id='l2h-4166' class="method">reset</tt></b>(</nobr></td> | |
74 | <td><var></var>)</td></tr></table></dt> | |
75 | <dd> | |
76 | Resets the pack buffer to the empty string. | |
77 | </dl> | |
78 | ||
79 | <P> | |
80 | In general, you can pack any of the most common XDR data types by | |
81 | calling the appropriate <code>pack_<var>type</var>()</code> method. Each method | |
82 | takes a single argument, the value to pack. The following simple data | |
83 | type packing methods are supported: <tt class="method">pack_uint()</tt>, | |
84 | <tt class="method">pack_int()</tt>, <tt class="method">pack_enum()</tt>, <tt class="method">pack_bool()</tt>, | |
85 | <tt class="method">pack_uhyper()</tt>, and <tt class="method">pack_hyper()</tt>. | |
86 | ||
87 | <P> | |
88 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
89 | <td><nobr><b><tt id='l2h-4167' xml:id='l2h-4167' class="method">pack_float</tt></b>(</nobr></td> | |
90 | <td><var>value</var>)</td></tr></table></dt> | |
91 | <dd> | |
92 | Packs the single-precision floating point number <var>value</var>. | |
93 | </dl> | |
94 | ||
95 | <P> | |
96 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
97 | <td><nobr><b><tt id='l2h-4168' xml:id='l2h-4168' class="method">pack_double</tt></b>(</nobr></td> | |
98 | <td><var>value</var>)</td></tr></table></dt> | |
99 | <dd> | |
100 | Packs the double-precision floating point number <var>value</var>. | |
101 | </dl> | |
102 | ||
103 | <P> | |
104 | The following methods support packing strings, bytes, and opaque data: | |
105 | ||
106 | <P> | |
107 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
108 | <td><nobr><b><tt id='l2h-4169' xml:id='l2h-4169' class="method">pack_fstring</tt></b>(</nobr></td> | |
109 | <td><var>n, s</var>)</td></tr></table></dt> | |
110 | <dd> | |
111 | Packs a fixed length string, <var>s</var>. <var>n</var> is the length of the | |
112 | string but it is <em>not</em> packed into the data buffer. The string | |
113 | is padded with null bytes if necessary to guaranteed 4 byte alignment. | |
114 | </dl> | |
115 | ||
116 | <P> | |
117 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
118 | <td><nobr><b><tt id='l2h-4170' xml:id='l2h-4170' class="method">pack_fopaque</tt></b>(</nobr></td> | |
119 | <td><var>n, data</var>)</td></tr></table></dt> | |
120 | <dd> | |
121 | Packs a fixed length opaque data stream, similarly to | |
122 | <tt class="method">pack_fstring()</tt>. | |
123 | </dl> | |
124 | ||
125 | <P> | |
126 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
127 | <td><nobr><b><tt id='l2h-4171' xml:id='l2h-4171' class="method">pack_string</tt></b>(</nobr></td> | |
128 | <td><var>s</var>)</td></tr></table></dt> | |
129 | <dd> | |
130 | Packs a variable length string, <var>s</var>. The length of the string is | |
131 | first packed as an unsigned integer, then the string data is packed | |
132 | with <tt class="method">pack_fstring()</tt>. | |
133 | </dl> | |
134 | ||
135 | <P> | |
136 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
137 | <td><nobr><b><tt id='l2h-4172' xml:id='l2h-4172' class="method">pack_opaque</tt></b>(</nobr></td> | |
138 | <td><var>data</var>)</td></tr></table></dt> | |
139 | <dd> | |
140 | Packs a variable length opaque data string, similarly to | |
141 | <tt class="method">pack_string()</tt>. | |
142 | </dl> | |
143 | ||
144 | <P> | |
145 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
146 | <td><nobr><b><tt id='l2h-4173' xml:id='l2h-4173' class="method">pack_bytes</tt></b>(</nobr></td> | |
147 | <td><var>bytes</var>)</td></tr></table></dt> | |
148 | <dd> | |
149 | Packs a variable length byte stream, similarly to <tt class="method">pack_string()</tt>. | |
150 | </dl> | |
151 | ||
152 | <P> | |
153 | The following methods support packing arrays and lists: | |
154 | ||
155 | <P> | |
156 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
157 | <td><nobr><b><tt id='l2h-4174' xml:id='l2h-4174' class="method">pack_list</tt></b>(</nobr></td> | |
158 | <td><var>list, pack_item</var>)</td></tr></table></dt> | |
159 | <dd> | |
160 | Packs a <var>list</var> of homogeneous items. This method is useful for | |
161 | lists with an indeterminate size; i.e. the size is not available until | |
162 | the entire list has been walked. For each item in the list, an | |
163 | unsigned integer <code>1</code> is packed first, followed by the data value | |
164 | from the list. <var>pack_item</var> is the function that is called to pack | |
165 | the individual item. At the end of the list, an unsigned integer | |
166 | <code>0</code> is packed. | |
167 | ||
168 | <P> | |
169 | For example, to pack a list of integers, the code might appear like | |
170 | this: | |
171 | ||
172 | <P> | |
173 | <div class="verbatim"><pre> | |
174 | import xdrlib | |
175 | p = xdrlib.Packer() | |
176 | p.pack_list([1, 2, 3], p.pack_int) | |
177 | </pre></div> | |
178 | </dl> | |
179 | ||
180 | <P> | |
181 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
182 | <td><nobr><b><tt id='l2h-4175' xml:id='l2h-4175' class="method">pack_farray</tt></b>(</nobr></td> | |
183 | <td><var>n, array, pack_item</var>)</td></tr></table></dt> | |
184 | <dd> | |
185 | Packs a fixed length list (<var>array</var>) of homogeneous items. <var>n</var> | |
186 | is the length of the list; it is <em>not</em> packed into the buffer, | |
187 | but a <tt class="exception">ValueError</tt> exception is raised if | |
188 | <code>len(<var>array</var>)</code> is not equal to <var>n</var>. As above, | |
189 | <var>pack_item</var> is the function used to pack each element. | |
190 | </dl> | |
191 | ||
192 | <P> | |
193 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
194 | <td><nobr><b><tt id='l2h-4176' xml:id='l2h-4176' class="method">pack_array</tt></b>(</nobr></td> | |
195 | <td><var>list, pack_item</var>)</td></tr></table></dt> | |
196 | <dd> | |
197 | Packs a variable length <var>list</var> of homogeneous items. First, the | |
198 | length of the list is packed as an unsigned integer, then each element | |
199 | is packed as in <tt class="method">pack_farray()</tt> above. | |
200 | </dl> | |
201 | ||
202 | <P> | |
203 | ||
204 | <DIV CLASS="navigation"> | |
205 | <div class='online-navigation'> | |
206 | <p></p><hr /> | |
207 | <table align="center" width="100%" cellpadding="0" cellspacing="2"> | |
208 | <tr> | |
209 | <td class='online-navigation'><a rel="prev" title="12.17 xdrlib " | |
210 | href="module-xdrlib.html"><img src='../icons/previous.png' | |
211 | border='0' height='32' alt='Previous Page' width='32' /></A></td> | |
212 | <td class='online-navigation'><a rel="parent" title="12.17 xdrlib " | |
213 | href="module-xdrlib.html"><img src='../icons/up.png' | |
214 | border='0' height='32' alt='Up One Level' width='32' /></A></td> | |
215 | <td class='online-navigation'><a rel="next" title="12.17.2 Unpacker Objects" | |
216 | href="xdr-unpacker-objects.html"><img src='../icons/next.png' | |
217 | border='0' height='32' alt='Next Page' width='32' /></A></td> | |
218 | <td align="center" width="100%">Python Library Reference</td> | |
219 | <td class='online-navigation'><a rel="contents" title="Table of Contents" | |
220 | href="contents.html"><img src='../icons/contents.png' | |
221 | border='0' height='32' alt='Contents' width='32' /></A></td> | |
222 | <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' | |
223 | border='0' height='32' alt='Module Index' width='32' /></a></td> | |
224 | <td class='online-navigation'><a rel="index" title="Index" | |
225 | href="genindex.html"><img src='../icons/index.png' | |
226 | border='0' height='32' alt='Index' width='32' /></A></td> | |
227 | </tr></table> | |
228 | <div class='online-navigation'> | |
229 | <b class="navlabel">Previous:</b> | |
230 | <a class="sectref" rel="prev" href="module-xdrlib.html">12.17 xdrlib </A> | |
231 | <b class="navlabel">Up:</b> | |
232 | <a class="sectref" rel="parent" href="module-xdrlib.html">12.17 xdrlib </A> | |
233 | <b class="navlabel">Next:</b> | |
234 | <a class="sectref" rel="next" href="xdr-unpacker-objects.html">12.17.2 Unpacker Objects</A> | |
235 | </div> | |
236 | </div> | |
237 | <hr /> | |
238 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> | |
239 | </DIV> | |
240 | <!--End of Navigation Panel--> | |
241 | <ADDRESS> | |
242 | See <i><a href="about.html">About this document...</a></i> for information on suggesting changes. | |
243 | </ADDRESS> | |
244 | </BODY> | |
245 | </HTML> |