cpython/Doc/c-api/codec.rst

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.. _codec-registry:
Codec registry and support functions
====================================
.. cfunction:: int PyCodec_Register(PyObject *search_function)
Register a new codec search function.
As side effect, this tries to load the :mod:`encodings` package, if not yet
done, to make sure that it is always first in the list of search functions.
.. cfunction:: int PyCodec_KnownEncoding(const char *encoding)
Return ``1`` or ``0`` depending on whether there is a registered codec for
the given *encoding*.
.. cfunction:: PyObject* PyCodec_Encode(PyObject *object, const char *encoding, const char *errors)
Generic codec based encoding API.
*object* is passed through the encoder function found for the given
*encoding* using the error handling method defined by *errors*. *errors* may
be *NULL* to use the default method defined for the codec. Raises a
:exc:`LookupError` if no encoder can be found.
.. cfunction:: PyObject* PyCodec_Decode(PyObject *object, const char *encoding, const char *errors)
Generic codec based decoding API.
*object* is passed through the decoder function found for the given
*encoding* using the error handling method defined by *errors*. *errors* may
be *NULL* to use the default method defined for the codec. Raises a
:exc:`LookupError` if no encoder can be found.
Codec lookup API
----------------
In the following functions, the *encoding* string is looked up converted to all
lower-case characters, which makes encodings looked up through this mechanism
effectively case-insensitive. If no codec is found, a :exc:`KeyError` is set
and *NULL* returned.
.. cfunction:: PyObject* PyCodec_Encoder(const char *encoding)
Get an encoder function for the given *encoding*.
.. cfunction:: PyObject* PyCodec_Decoder(const char *encoding)
Get a decoder function for the given *encoding*.
.. cfunction:: PyObject* PyCodec_IncrementalEncoder(const char *encoding, const char *errors)
Get an :class:`IncrementalEncoder` object for the given *encoding*.
.. cfunction:: PyObject* PyCodec_IncrementalDecoder(const char *encoding, const char *errors)
Get an :class:`IncrementalDecoder` object for the given *encoding*.
.. cfunction:: PyObject* PyCodec_StreamReader(const char *encoding, PyObject *stream, const char *errors)
Get a :class:`StreamReader` factory function for the given *encoding*.
.. cfunction:: PyObject* PyCodec_StreamWriter(const char *encoding, PyObject *stream, const char *errors)
Get a :class:`StreamWriter` factory function for the given *encoding*.
Registry API for Unicode encoding error handlers
------------------------------------------------
.. cfunction:: int PyCodec_RegisterError(const char *name, PyObject *error)
Register the error handling callback function *error* under the given *name*.
This callback function will be called by a codec when it encounters
unencodable characters/undecodable bytes and *name* is specified as the error
parameter in the call to the encode/decode function.
The callback gets a single argument, an instance of
:exc:`UnicodeEncodeError`, :exc:`UnicodeDecodeError` or
:exc:`UnicodeTranslateError` that holds information about the problematic
sequence of characters or bytes and their offset in the original string (see
:ref:`unicodeexceptions` for functions to extract this information). The
callback must either raise the given exception, or return a two-item tuple
containing the replacement for the problematic sequence, and an integer
giving the offset in the original string at which encoding/decoding should be
resumed.
Return ``0`` on success, ``-1`` on error.
.. cfunction:: PyObject* PyCodec_LookupError(const char *name)
Lookup the error handling callback function registered under *name*. As a
special case *NULL* can be passed, in which case the error handling callback
for "strict" will be returned.
.. cfunction:: PyObject* PyCodec_StrictErrors(PyObject *exc)
Raise *exc* as an exception.
.. cfunction:: PyObject* PyCodec_IgnoreErrors(PyObject *exc)
Ignore the unicode error, skipping the faulty input.
.. cfunction:: PyObject* PyCodec_ReplaceErrors(PyObject *exc)
Replace the unicode encode error with ``?`` or ``U+FFFD``.
.. cfunction:: PyObject* PyCodec_XMLCharRefReplaceErrors(PyObject *exc)
Replace the unicode encode error with XML character references.
.. cfunction:: PyObject* PyCodec_BackslashReplaceErrors(PyObject *exc)
Replace the unicode encode error with backslash escapes (``\x``, ``\u`` and
``\U``).