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4.7.1.1 Codec Objects

The `Codec` class defines these methods which also define the function interfaces of the stateless encoder and decoder:

`encode` (input[, errors])
  Encodes the object input and returns a tuple (output object, length consumed).

  errors defines the error handling to apply. It defaults to `'strict'` handling.

  The method may not store state in the `Codec` instance. Use `StreamCodec` for codecs which have to keep state in order to make encoding/decoding efficient.

  The encoder must be able to handle zero length input and return an empty object of the output object type in this situation.

`decode` (input[, errors])
  Decodes the object input and returns a tuple (output object, length consumed).

  input must be an object which provides the `bf_getreadbuf` buffer slot. Python strings, buffer objects and memory mapped files are examples of objects providing this slot.

  errors defines the error handling to apply. It defaults to `'strict'` handling.

  The method may not store state in the `Codec` instance. Use `StreamCodec` for codecs which have to keep state in order to make encoding/decoding efficient.

  The decoder must be able to handle zero length input and return an empty object of the output object type in this situation.

The `StreamWriter` and `StreamReader` classes provide generic working interfaces which can be used to implement new encodings submodules very easily. See `encodings.utf_8` for an example on how this is done.