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<H2><A NAME="SECTION006810000000000000000">
4.8.1 Codec Base Classes</A>
</H2>
<P>
The <tt class="module">codecs</tt> defines a set of base classes which define the
interface and can also be used to easily write you own codecs for use
in Python.
<P>
Each codec has to define four interfaces to make it usable as codec in
Python: stateless encoder, stateless decoder, stream reader and stream
writer. The stream reader and writers typically reuse the stateless
encoder/decoder to implement the file protocols.
<P>
The <tt class="class">Codec</tt> class defines the interface for stateless
encoders/decoders.
<P>
To simplify and standardize error handling, the <tt class="method">encode()</tt> and
<tt class="method">decode()</tt> methods may implement different error handling
schemes by providing the <var>errors</var> string argument. The following
string values are defined and implemented by all standard Python
codecs:
<P>
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<th align="left"><b>Value</b> </th>
<th align="left"><b>Meaning</b> </th>
</tr>
</thead>
<tbody valign="baseline">
<tr><td align="left" valign="baseline"><code>'strict'</code></td>
<td align="left">Raise <tt class="exception">ValueError</tt> (or a subclass);
this is the default.</td>
<tr><td align="left" valign="baseline"><code>'ignore'</code></td>
<td align="left">Ignore the character and continue with the next.</td>
<tr><td align="left" valign="baseline"><code>'replace'</code></td>
<td align="left">Replace with a suitable replacement character;
Python will use the official U+FFFD REPLACEMENT
CHARACTER for the built-in Unicode codecs.</td></tbody>
</table>
<P>
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<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a>
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<LI><A href="codec-objects.html">4.8.1.1 Codec Objects</a>
<LI><A href="stream-writer-objects.html">4.8.1.2 StreamWriter Objects</a>
<LI><A href="stream-reader-objects.html">4.8.1.3 StreamReader Objects</a>
<LI><A href="stream-reader-writer.html">4.8.1.4 StreamReaderWriter Objects</a>
<LI><A href="stream-recoder-objects.html">4.8.1.5 StreamRecoder Objects</a>
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<span class="release-info">Release 2.2, documentation updated on December 21, 2001.</span>
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