python_doc_md/Advanced/c-api/codec.md

Codec registry and support functions {#codec-registry}

Register a new codec search function.

As a side effect, this tries to load the !encodings{.interpreted-text role="mod"} package, if not yet done, to make sure that it is always first in the list of search functions.

Unregister a codec search function and clear the registry's cache. If the search function is not registered, do nothing. Return 0 on success. Raise an exception and return -1 on error.

::: versionadded 3.10 :::

Return 1 or 0 depending on whether there is a registered codec for the given encoding. This function always succeeds.

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 LookupError{.interpreted-text role="exc"} if no encoder can be found.

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 LookupError{.interpreted-text role="exc"} if no decoder 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 KeyError{.interpreted-text role="exc"} is set and NULL returned.

Get an encoder function for the given encoding.

Get a decoder function for the given encoding.

Get an ~codecs.IncrementalEncoder{.interpreted-text role="class"} object for the given encoding.

Get an ~codecs.IncrementalDecoder{.interpreted-text role="class"} object for the given encoding.

Get a ~codecs.StreamReader{.interpreted-text role="class"} factory function for the given encoding.

Get a ~codecs.StreamWriter{.interpreted-text role="class"} factory function for the given encoding.

Registry API for Unicode encoding error handlers

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 UnicodeEncodeError{.interpreted-text role="exc"}, UnicodeDecodeError{.interpreted-text role="exc"} or UnicodeTranslateError{.interpreted-text role="exc"} that holds information about the problematic sequence of characters or bytes and their offset in the original string (see unicodeexceptions{.interpreted-text role="ref"} 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.

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.

Raise exc as an exception.

Ignore the unicode error, skipping the faulty input.

Replace the unicode encode error with ? or U+FFFD.

Replace the unicode encode error with XML character references.

Replace the unicode encode error with backslash escapes (\x, \u and \U).

Replace the unicode encode error with \N{...} escapes.

::: versionadded 3.5 :::

Codec utility variables

A string constant containing the lowercase hexadecimal digits: "0123456789abcdef".

::: versionadded 3.3 :::