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132 lines
4.3 KiB
132 lines
4.3 KiB
""" Standard "encodings" Package |
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Standard Python encoding modules are stored in this package |
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directory. |
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Codec modules must have names corresponding to normalized encoding |
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names as defined in the normalize_encoding() function below, e.g. |
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'utf-8' must be implemented by the module 'utf_8.py'. |
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Each codec module must export the following interface: |
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* getregentry() -> (encoder, decoder, stream_reader, stream_writer) |
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The getregentry() API must return callable objects which adhere to |
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the Python Codec Interface Standard. |
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In addition, a module may optionally also define the following |
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APIs which are then used by the package's codec search function: |
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* getaliases() -> sequence of encoding name strings to use as aliases |
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Alias names returned by getaliases() must be normalized encoding |
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names as defined by normalize_encoding(). |
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Written by Marc-Andre Lemburg (mal@lemburg.com). |
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(c) Copyright CNRI, All Rights Reserved. NO WARRANTY. |
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"""#" |
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# modified by Jeffrey Lundin for Cyan Worlds, Inc. |
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import codecs, exceptions, types |
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_cache = {} |
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_unknown = '--unknown--' |
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_import_tail = ['*'] |
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_norm_encoding_map = (' . ' |
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'0123456789 ABCDEFGHIJKLMNOPQRSTUVWXYZ ' |
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' abcdefghijklmnopqrstuvwxyz ' |
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' ' |
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' ' |
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' ') |
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class CodecRegistryError(exceptions.LookupError, |
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exceptions.SystemError): |
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pass |
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def normalize_encoding(encoding): |
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""" Normalize an encoding name. |
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Normalization works as follows: all non-alphanumeric |
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characters except the dot used for Python package names are |
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collapsed and replaced with a single underscore, e.g. ' -;#' |
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becomes '_'. Leading and trailing underscores are removed. |
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Note that encoding names should be ASCII only; if they do use |
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non-ASCII characters, these must be Latin-1 compatible. |
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""" |
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# Make sure we have an 8-bit string, because .translate() works |
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# differently for Unicode strings. |
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if type(encoding) is types.UnicodeType: |
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# Note that .encode('latin-1') does *not* use the codec |
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# registry, so this call doesn't recurse. (See unicodeobject.c |
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# PyUnicode_AsEncodedString() for details) |
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encoding = encoding.encode('latin-1') |
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return '_'.join(encoding.translate(_norm_encoding_map).split()) |
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def search_function(encoding): |
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# Cache lookup |
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entry = _cache.get(encoding, _unknown) |
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if entry is not _unknown: |
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return entry |
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# Import the module: |
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# |
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# First look in the encodings package, then try to lookup the |
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# encoding in the aliases mapping and retry the import using the |
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# default import module lookup scheme with the alias name. |
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# |
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modname = normalize_encoding(encoding) |
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try: |
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mod = __import__('encoding_' + modname, |
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globals(), locals(), _import_tail) |
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except ImportError: |
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mod = None |
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try: |
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getregentry = mod.getregentry |
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except AttributeError: |
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# Not a codec module |
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mod = None |
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if mod is None: |
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# Cache misses |
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_cache[encoding] = None |
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return None |
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# Now ask the module for the registry entry |
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entry = tuple(getregentry()) |
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if len(entry) != 4: |
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raise CodecRegistryError,\ |
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'module "%s" (%s) failed to register' % \ |
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(mod.__name__, mod.__file__) |
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for obj in entry: |
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if not callable(obj): |
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raise CodecRegistryError,\ |
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'incompatible codecs in module "%s" (%s)' % \ |
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(mod.__name__, mod.__file__) |
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# Cache the codec registry entry |
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_cache[encoding] = entry |
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# Register its aliases (without overwriting previously registered |
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# aliases) |
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try: |
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codecaliases = mod.getaliases() |
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except AttributeError: |
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pass |
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else: |
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import aliases |
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for alias in codecaliases: |
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if not aliases.aliases.has_key(alias): |
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aliases.aliases[alias] = modname |
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# Return the registry entry |
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return entry |
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# Register the search_function in the Python codec registry |
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codecs.register(search_function)
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