projects / OpenSPARC-T2-SAM / blame
| 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="module-bz2.html" /> | |
| 13 | <link rel="prev" href="module-zlib.html" /> | |
| 14 | <link rel="parent" href="someos.html" /> | |
| 15 | <link rel="next" href="module-bz2.html" /> | |
| 16 | <meta name='aesop' content='information' /> | |
| 17 | <title>7.16 gzip -- Support for gzip files</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="7.15 zlib " | |
| 25 | href="module-zlib.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="7. Optional Operating System" | |
| 28 | href="someos.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="7.17 bz2 " | |
| 31 | href="module-bz2.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-zlib.html">7.15 zlib </A> | |
| 46 | <b class="navlabel">Up:</b> | |
| 47 | <a class="sectref" rel="parent" href="someos.html">7. Optional Operating System</A> | |
| 48 | <b class="navlabel">Next:</b> | |
| 49 | <a class="sectref" rel="next" href="module-bz2.html">7.17 bz2 </A> | |
| 50 | </div> | |
| 51 | <hr /></div> | |
| 52 | </DIV> | |
| 53 | <!--End of Navigation Panel--> | |
| 54 | ||
| 55 | <H1><A NAME="SECTION0091600000000000000000"> | |
| 56 | 7.16 <tt class="module">gzip</tt> -- | |
| 57 | Support for <b class="program">gzip</b> files</A> | |
| 58 | </H1> | |
| 59 | ||
| 60 | <P> | |
| 61 | <A NAME="module-gzip"></A> | |
| 62 | ||
| 63 | <P> | |
| 64 | The data compression provided by the <code>zlib</code> module is compatible | |
| 65 | with that used by the GNU compression program <b class="program">gzip</b>. | |
| 66 | Accordingly, the <tt class="module">gzip</tt> module provides the <tt class="class">GzipFile</tt> | |
| 67 | class to read and write <b class="program">gzip</b>-format files, automatically | |
| 68 | compressing or decompressing the data so it looks like an ordinary | |
| 69 | file object. Note that additional file formats which can be | |
| 70 | decompressed by the <b class="program">gzip</b> and <b class="program">gunzip</b> programs, such | |
| 71 | as those produced by <b class="program">compress</b> and <b class="program">pack</b>, are not | |
| 72 | supported by this module. | |
| 73 | ||
| 74 | <P> | |
| 75 | The module defines the following items: | |
| 76 | ||
| 77 | <P> | |
| 78 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
| 79 | <td><nobr><b><span class="typelabel">class</span> <tt id='l2h-2830' xml:id='l2h-2830' class="class">GzipFile</tt></b>(</nobr></td> | |
| 80 | <td><var></var><big>[</big><var>filename</var><big>[</big><var>, mode</var><big>[</big><var>, | |
| 81 | compresslevel</var><big>[</big><var>, fileobj</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> | |
| 82 | <dd> | |
| 83 | Constructor for the <tt class="class">GzipFile</tt> class, which simulates most of | |
| 84 | the methods of a file object, with the exception of the <tt class="method">readinto()</tt> | |
| 85 | and <tt class="method">truncate()</tt> methods. At least one of | |
| 86 | <var>fileobj</var> and <var>filename</var> must be given a non-trivial value. | |
| 87 | ||
| 88 | <P> | |
| 89 | The new class instance is based on <var>fileobj</var>, which can be a | |
| 90 | regular file, a <tt class="class">StringIO</tt> object, or any other object which | |
| 91 | simulates a file. It defaults to <code>None</code>, in which case | |
| 92 | <var>filename</var> is opened to provide a file object. | |
| 93 | ||
| 94 | <P> | |
| 95 | When <var>fileobj</var> is not <code>None</code>, the <var>filename</var> argument is | |
| 96 | only used to be included in the <b class="program">gzip</b> file header, which may | |
| 97 | includes the original filename of the uncompressed file. It defaults | |
| 98 | to the filename of <var>fileobj</var>, if discernible; otherwise, it | |
| 99 | defaults to the empty string, and in this case the original filename | |
| 100 | is not included in the header. | |
| 101 | ||
| 102 | <P> | |
| 103 | The <var>mode</var> argument can be any of <code>'r'</code>, <code>'rb'</code>, | |
| 104 | <code>'a'</code>, <code>'ab'</code>, <code>'w'</code>, or <code>'wb'</code>, depending on | |
| 105 | whether the file will be read or written. The default is the mode of | |
| 106 | <var>fileobj</var> if discernible; otherwise, the default is <code>'rb'</code>. | |
| 107 | If not given, the 'b' flag will be added to the mode to ensure the | |
| 108 | file is opened in binary mode for cross-platform portability. | |
| 109 | ||
| 110 | <P> | |
| 111 | The <var>compresslevel</var> argument is an integer from <code>1</code> to | |
| 112 | <code>9</code> controlling the level of compression; <code>1</code> is fastest and | |
| 113 | produces the least compression, and <code>9</code> is slowest and produces | |
| 114 | the most compression. The default is <code>9</code>. | |
| 115 | ||
| 116 | <P> | |
| 117 | Calling a <tt class="class">GzipFile</tt> object's <tt class="method">close()</tt> method does not | |
| 118 | close <var>fileobj</var>, since you might wish to append more material | |
| 119 | after the compressed data. This also allows you to pass a | |
| 120 | <tt class="class">StringIO</tt> object opened for writing as <var>fileobj</var>, and | |
| 121 | retrieve the resulting memory buffer using the <tt class="class">StringIO</tt> | |
| 122 | object's <tt class="method">getvalue()</tt> method. | |
| 123 | </dl> | |
| 124 | ||
| 125 | <P> | |
| 126 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> | |
| 127 | <td><nobr><b><tt id='l2h-2831' xml:id='l2h-2831' class="function">open</tt></b>(</nobr></td> | |
| 128 | <td><var>filename</var><big>[</big><var>, mode</var><big>[</big><var>, compresslevel</var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> | |
| 129 | <dd> | |
| 130 | This is a shorthand for <code>GzipFile(<var>filename</var>,</code> | |
| 131 | <code><var>mode</var>,</code> <code><var>compresslevel</var>)</code>. The <var>filename</var> | |
| 132 | argument is required; <var>mode</var> defaults to <code>'rb'</code> and | |
| 133 | <var>compresslevel</var> defaults to <code>9</code>. | |
| 134 | </dl> | |
| 135 | ||
| 136 | <P> | |
| 137 | <div class="seealso"> | |
| 138 | <p class="heading">See Also:</p> | |
| 139 | ||
| 140 | <dl compact="compact" class="seemodule"> | |
| 141 | <dt>Module <b><tt class="module"><a href="module-zlib.html">zlib</a></tt>:</b> | |
| 142 | <dd>The basic data compression module needed to support | |
| 143 | the <b class="program">gzip</b> file format. | |
| 144 | </dl> | |
| 145 | </div> | |
| 146 | ||
| 147 | <DIV CLASS="navigation"> | |
| 148 | <div class='online-navigation'> | |
| 149 | <p></p><hr /> | |
| 150 | <table align="center" width="100%" cellpadding="0" cellspacing="2"> | |
| 151 | <tr> | |
| 152 | <td class='online-navigation'><a rel="prev" title="7.15 zlib " | |
| 153 | href="module-zlib.html"><img src='../icons/previous.png' | |
| 154 | border='0' height='32' alt='Previous Page' width='32' /></A></td> | |
| 155 | <td class='online-navigation'><a rel="parent" title="7. Optional Operating System" | |
| 156 | href="someos.html"><img src='../icons/up.png' | |
| 157 | border='0' height='32' alt='Up One Level' width='32' /></A></td> | |
| 158 | <td class='online-navigation'><a rel="next" title="7.17 bz2 " | |
| 159 | href="module-bz2.html"><img src='../icons/next.png' | |
| 160 | border='0' height='32' alt='Next Page' width='32' /></A></td> | |
| 161 | <td align="center" width="100%">Python Library Reference</td> | |
| 162 | <td class='online-navigation'><a rel="contents" title="Table of Contents" | |
| 163 | href="contents.html"><img src='../icons/contents.png' | |
| 164 | border='0' height='32' alt='Contents' width='32' /></A></td> | |
| 165 | <td class='online-navigation'><a href="modindex.html" title="Module Index"><img src='../icons/modules.png' | |
| 166 | border='0' height='32' alt='Module Index' width='32' /></a></td> | |
| 167 | <td class='online-navigation'><a rel="index" title="Index" | |
| 168 | href="genindex.html"><img src='../icons/index.png' | |
| 169 | border='0' height='32' alt='Index' width='32' /></A></td> | |
| 170 | </tr></table> | |
| 171 | <div class='online-navigation'> | |
| 172 | <b class="navlabel">Previous:</b> | |
| 173 | <a class="sectref" rel="prev" href="module-zlib.html">7.15 zlib </A> | |
| 174 | <b class="navlabel">Up:</b> | |
| 175 | <a class="sectref" rel="parent" href="someos.html">7. Optional Operating System</A> | |
| 176 | <b class="navlabel">Next:</b> | |
| 177 | <a class="sectref" rel="next" href="module-bz2.html">7.17 bz2 </A> | |
| 178 | </div> | |
| 179 | </div> | |
| 180 | <hr /> | |
| 181 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> | |
| 182 | </DIV> | |
| 183 | <!--End of Navigation Panel--> | |
| 184 | <ADDRESS> | |
| 185 | See <i><a href="about.html">About this document...</a></i> for information on suggesting changes. | |
| 186 | </ADDRESS> | |
| 187 | </BODY> | |
| 188 | </HTML> |