[Python-Dev] Some thoughts on the codecs...

[Andy Robinson]

On Tue, 16 Nov 1999 09:39:20 +0100, you wrote:

>1) codes written according to the "data
>   consumer model", instead of the "stream"
>   model.
>
>        class myDecoder:
>            def __init__(self, target):
>                self.target = target
>                self.state = ...
>            def feed(self, data):
>                ... extract as much data as possible ...
>                self.target.feed(extracted data)
>            def close(self):
>                ... extract what's left ...
>                self.target.feed(additional data)
>                self.target.close()
>
Apart from feed() instead of write(), how is that different from a
Java-like Stream writer as Guido suggested?  He said:

>Andy's file translation example could then be written as follows:
>
># assuming variables input_file, input_encoding, output_file,
># output_encoding, and constant BUFFER_SIZE
>
>f = open(input_file, "rb")
>f1 = unicodec.codecs[input_encoding].stream_reader(f)
>g = open(output_file, "wb")
>g1 = unicodec.codecs[output_encoding].stream_writer(f)
>
>while 1:
>      buffer = f1.read(BUFFER_SIZE)
>      if not buffer:
>	 break
>      f2.write(buffer)
>
>f2.close()
>f1.close()
>
>Note that we could possibly make these the only API that a codec needs
>to provide; the string object <--> unicode object conversions can be
>done using this and the cStringIO module.  (On the other hand it seems
>a common case that would be quite useful.)

- Andy