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<H3>
<BR>
4.7.1.5 StreamRecoder Objects
</H3>
<P>
The <tt class="class">StreamRecoder</tt> provide a frontend - backend view of
encoding data which is sometimes useful when dealing with different
encoding environments.
<P>
The design is such that one can use the factory functions returned by
the <tt class="function">lookup()</tt> function to construct the instance.
<P>
<dl><dt><b><a name='l2h-673'><tt class='class'>StreamRecoder</tt></a></b> (<var>stream, encode, decode,
Reader, Writer, errors</var>)
<dd>
Creates a <tt class="class">StreamRecoder</tt> instance which implements a two-way
conversion: <var>encode</var> and <var>decode</var> work on the frontend (the
input to <tt class="method">read()</tt> and output of <tt class="method">write()</tt>) while
<var>Reader</var> and <var>Writer</var> work on the backend (reading and
writing to the stream).
<P>
You can use these objects to do transparent direct recodings from
e.g. Latin-1 to UTF-8 and back.
<P>
<var>stream</var> must be a file-like object.
<P>
<var>encode</var>, <var>decode</var> must adhere to the <tt class="class">Codec</tt>
interface, <var>Reader</var>, <var>Writer</var> must be factory functions or
classes providing objects of the the <tt class="class">StreamReader</tt> and
<tt class="class">StreamWriter</tt> interface respectively.
<P>
<var>encode</var> and <var>decode</var> are needed for the frontend
translation, <var>Reader</var> and <var>Writer</var> for the backend
translation. The intermediate format used is determined by the two
sets of codecs, e.g. the Unicode codecs will use Unicode as
intermediate encoding.
<P>
Error handling is done in the same way as defined for the
stream readers and writers.
</dl>
<P>
<tt class="class">StreamRecoder</tt> instances define the combined interfaces of
<tt class="class">StreamReader</tt> and <tt class="class">StreamWriter</tt> classes. They inherit
all other methods and attribute from the underlying stream.
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