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55 | <H2><A NAME="SECTION00141720000000000000000"></A><A NAME="xdr-unpacker-objects"></A> | |
56 | <BR> | |
57 | 12.17.2 Unpacker Objects | |
58 | </H2> | |
59 | ||
60 | <P> | |
61 | The <tt class="class">Unpacker</tt> class offers the following methods: | |
62 | ||
63 | <P> | |
64 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
65 | <td><nobr><b><tt id='l2h-4177' xml:id='l2h-4177' class="method">reset</tt></b>(</nobr></td> | |
66 | <td><var>data</var>)</td></tr></table></dt> | |
67 | <dd> | |
68 | Resets the string buffer with the given <var>data</var>. | |
69 | </dl> | |
70 | ||
71 | <P> | |
72 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
73 | <td><nobr><b><tt id='l2h-4178' xml:id='l2h-4178' class="method">get_position</tt></b>(</nobr></td> | |
74 | <td><var></var>)</td></tr></table></dt> | |
75 | <dd> | |
76 | Returns the current unpack position in the data buffer. | |
77 | </dl> | |
78 | ||
79 | <P> | |
80 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
81 | <td><nobr><b><tt id='l2h-4179' xml:id='l2h-4179' class="method">set_position</tt></b>(</nobr></td> | |
82 | <td><var>position</var>)</td></tr></table></dt> | |
83 | <dd> | |
84 | Sets the data buffer unpack position to <var>position</var>. You should be | |
85 | careful about using <tt class="method">get_position()</tt> and <tt class="method">set_position()</tt>. | |
86 | </dl> | |
87 | ||
88 | <P> | |
89 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
90 | <td><nobr><b><tt id='l2h-4180' xml:id='l2h-4180' class="method">get_buffer</tt></b>(</nobr></td> | |
91 | <td><var></var>)</td></tr></table></dt> | |
92 | <dd> | |
93 | Returns the current unpack data buffer as a string. | |
94 | </dl> | |
95 | ||
96 | <P> | |
97 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
98 | <td><nobr><b><tt id='l2h-4181' xml:id='l2h-4181' class="method">done</tt></b>(</nobr></td> | |
99 | <td><var></var>)</td></tr></table></dt> | |
100 | <dd> | |
101 | Indicates unpack completion. Raises an <tt class="exception">Error</tt> exception | |
102 | if all of the data has not been unpacked. | |
103 | </dl> | |
104 | ||
105 | <P> | |
106 | In addition, every data type that can be packed with a <tt class="class">Packer</tt>, | |
107 | can be unpacked with an <tt class="class">Unpacker</tt>. Unpacking methods are of the | |
108 | form <code>unpack_<var>type</var>()</code>, and take no arguments. They return the | |
109 | unpacked object. | |
110 | ||
111 | <P> | |
112 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
113 | <td><nobr><b><tt id='l2h-4182' xml:id='l2h-4182' class="method">unpack_float</tt></b>(</nobr></td> | |
114 | <td><var></var>)</td></tr></table></dt> | |
115 | <dd> | |
116 | Unpacks a single-precision floating point number. | |
117 | </dl> | |
118 | ||
119 | <P> | |
120 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
121 | <td><nobr><b><tt id='l2h-4183' xml:id='l2h-4183' class="method">unpack_double</tt></b>(</nobr></td> | |
122 | <td><var></var>)</td></tr></table></dt> | |
123 | <dd> | |
124 | Unpacks a double-precision floating point number, similarly to | |
125 | <tt class="method">unpack_float()</tt>. | |
126 | </dl> | |
127 | ||
128 | <P> | |
129 | In addition, the following methods unpack strings, bytes, and opaque | |
130 | data: | |
131 | ||
132 | <P> | |
133 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
134 | <td><nobr><b><tt id='l2h-4184' xml:id='l2h-4184' class="method">unpack_fstring</tt></b>(</nobr></td> | |
135 | <td><var>n</var>)</td></tr></table></dt> | |
136 | <dd> | |
137 | Unpacks and returns a fixed length string. <var>n</var> is the number of | |
138 | characters expected. Padding with null bytes to guaranteed 4 byte | |
139 | alignment is assumed. | |
140 | </dl> | |
141 | ||
142 | <P> | |
143 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
144 | <td><nobr><b><tt id='l2h-4185' xml:id='l2h-4185' class="method">unpack_fopaque</tt></b>(</nobr></td> | |
145 | <td><var>n</var>)</td></tr></table></dt> | |
146 | <dd> | |
147 | Unpacks and returns a fixed length opaque data stream, similarly to | |
148 | <tt class="method">unpack_fstring()</tt>. | |
149 | </dl> | |
150 | ||
151 | <P> | |
152 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
153 | <td><nobr><b><tt id='l2h-4186' xml:id='l2h-4186' class="method">unpack_string</tt></b>(</nobr></td> | |
154 | <td><var></var>)</td></tr></table></dt> | |
155 | <dd> | |
156 | Unpacks and returns a variable length string. The length of the | |
157 | string is first unpacked as an unsigned integer, then the string data | |
158 | is unpacked with <tt class="method">unpack_fstring()</tt>. | |
159 | </dl> | |
160 | ||
161 | <P> | |
162 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
163 | <td><nobr><b><tt id='l2h-4187' xml:id='l2h-4187' class="method">unpack_opaque</tt></b>(</nobr></td> | |
164 | <td><var></var>)</td></tr></table></dt> | |
165 | <dd> | |
166 | Unpacks and returns a variable length opaque data string, similarly to | |
167 | <tt class="method">unpack_string()</tt>. | |
168 | </dl> | |
169 | ||
170 | <P> | |
171 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
172 | <td><nobr><b><tt id='l2h-4188' xml:id='l2h-4188' class="method">unpack_bytes</tt></b>(</nobr></td> | |
173 | <td><var></var>)</td></tr></table></dt> | |
174 | <dd> | |
175 | Unpacks and returns a variable length byte stream, similarly to | |
176 | <tt class="method">unpack_string()</tt>. | |
177 | </dl> | |
178 | ||
179 | <P> | |
180 | The following methods support unpacking arrays and lists: | |
181 | ||
182 | <P> | |
183 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
184 | <td><nobr><b><tt id='l2h-4189' xml:id='l2h-4189' class="method">unpack_list</tt></b>(</nobr></td> | |
185 | <td><var>unpack_item</var>)</td></tr></table></dt> | |
186 | <dd> | |
187 | Unpacks and returns a list of homogeneous items. The list is unpacked | |
188 | one element at a time | |
189 | by first unpacking an unsigned integer flag. If the flag is <code>1</code>, | |
190 | then the item is unpacked and appended to the list. A flag of | |
191 | <code>0</code> indicates the end of the list. <var>unpack_item</var> is the | |
192 | function that is called to unpack the items. | |
193 | </dl> | |
194 | ||
195 | <P> | |
196 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
197 | <td><nobr><b><tt id='l2h-4190' xml:id='l2h-4190' class="method">unpack_farray</tt></b>(</nobr></td> | |
198 | <td><var>n, unpack_item</var>)</td></tr></table></dt> | |
199 | <dd> | |
200 | Unpacks and returns (as a list) a fixed length array of homogeneous | |
201 | items. <var>n</var> is number of list elements to expect in the buffer. | |
202 | As above, <var>unpack_item</var> is the function used to unpack each element. | |
203 | </dl> | |
204 | ||
205 | <P> | |
206 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
207 | <td><nobr><b><tt id='l2h-4191' xml:id='l2h-4191' class="method">unpack_array</tt></b>(</nobr></td> | |
208 | <td><var>unpack_item</var>)</td></tr></table></dt> | |
209 | <dd> | |
210 | Unpacks and returns a variable length <var>list</var> of homogeneous items. | |
211 | First, the length of the list is unpacked as an unsigned integer, then | |
212 | each element is unpacked as in <tt class="method">unpack_farray()</tt> above. | |
213 | </dl> | |
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