1 files changed, 78 insertions, 0 deletions
diff --git a/Lib/encodings/__init__.py b/Lib/encodings/__init__.py
new file mode 100644
index 0000000..c33b822
--- /dev/null
+++ b/Lib/encodings/__init__.py
@@ -0,0 +1,78 @@
+""" Standard "encodings" Package
+
+    Standard Python encoding modules are stored in this package
+    directory.
+
+    Codec modules must have names corresponding to standard lower-case
+    encoding names. Hyphens are automatically converted to
+    underscores, e.g. 'utf-8' is looked up as module utf_8.
+
+    Each codec module must export the following interface:
+
+    * getregentry() -> (encoder, decoder, stream_reader, stream_writer)
+    The getregentry() API must return callable objects which adhere to
+    the Python Codec Interface Standard.
+
+    In addition, a module may optionally also define the following
+    APIs which are then used by the package's codec search function:
+
+    * getaliases() -> sequence of encoding name strings to use as aliases
+
+    Alias names returned by getaliases() must be lower-case.
+
+
+Written by Marc-Andre Lemburg (mal@lemburg.com).
+
+(c) Copyright CNRI, All Rights Reserved. NO WARRANTY.
+
+"""#"
+
+import string,codecs,aliases
+
+_cache = {}
+_unkown = '--unkown--'
+
+def search_function(encoding):
+    
+    # Cache lookup
+    entry = _cache.get(encoding,_unkown)
+    if entry is not _unkown:
+        return entry
+
+    # Import the module
+    modname = string.replace(encoding,'-','_')
+    modname = aliases.aliases.get(modname,modname)
+    try:
+        mod = __import__(modname,globals(),locals(),'*')
+    except ImportError,why:
+        _cache[encoding] = None
+        return None
+    
+    # Now ask the module for the registry entry
+    try:
+        entry = tuple(mod.getregentry())
+    except AttributeError:
+        entry = ()
+    if len(entry) != 4:
+        raise SystemError,\
+              'module "%s.%s" failed to register' % \
+              (__name__,modname)
+    for obj in entry:
+        if not callable(obj):
+            raise SystemError,\
+                  'incompatible codecs in module "%s.%s"' % \
+                  (__name__,modname)
+
+    # Cache the encoding and its aliases
+    _cache[encoding] = entry
+    try:
+        codecaliases = mod.getaliases()
+    except AttributeError:
+        pass
+    else:
+        for alias in codecaliases:
+            _cache[alias] = entry
+    return entry
+
+# Register the search_function in the Python codec registry
+codecs.register(search_function)