diff options
Diffstat (limited to 'Lib/codecs.py')
| -rw-r--r-- | Lib/codecs.py | 142 |
1 files changed, 119 insertions, 23 deletions
diff --git a/Lib/codecs.py b/Lib/codecs.py index 5c669c0..6a61e1a 100644 --- a/Lib/codecs.py +++ b/Lib/codecs.py @@ -127,14 +127,19 @@ class StreamWriter(Codec): self.stream = stream self.errors = errors - def write(self,object): + def write(self, object): """ Writes the object's contents encoded to self.stream. """ data, consumed = self.encode(object,self.errors) self.stream.write(data) - # XXX .writelines() ? + def writelines(self, list): + + """ Writes the concatenated list of strings to the stream + using .write(). + """ + self.write(''.join(list)) def reset(self): @@ -179,7 +184,7 @@ class StreamReader(Codec): self.stream = stream self.errors = errors - def read(self,size=-1): + def read(self, size=-1): """ Decodes data from the stream self.stream and returns the resulting object. @@ -221,8 +226,44 @@ class StreamReader(Codec): else: return object - # XXX .readline() and .readlines() (these are hard to implement - # without using buffers for keeping read-ahead data) + def readline(self, size=None): + + """ Read one line from the input stream and return the + decoded data. + + Note: Unlike the .readlines() method, line breaking must + be implemented by the underlying stream's .readline() + method -- there is currently no support for line breaking + using the codec decoder due to lack of line buffering. + + size, if given, is passed as size argument to the stream's + .readline() method. + + """ + if size is None: + line = self.stream.readline() + else: + line = self.stream.readline(size) + return self.decode(line)[0] + + + def readlines(self, sizehint=0): + + """ Read all lines available on the input stream + and return them as list of lines. + + Line breaks are implemented using the codec's decoder + method and are included in the list entries. + + sizehint, if given, is passed as size argument to the + stream's .read() method. + + """ + if sizehint is None: + data = self.stream.read() + else: + data = self.stream.read(sizehint) + return self.decode(data)[0].splitlines(1) def reset(self): @@ -247,6 +288,9 @@ class StreamReader(Codec): class StreamReaderWriter: + # Optional attributes set by the file wrappers below + encoding = 'unknown' + def __init__(self,stream,Reader,Writer,errors='strict'): """ Creates a StreamReaderWriter instance. @@ -269,10 +313,22 @@ class StreamReaderWriter: return self.reader.read(size) + def readline(size=None): + + return self.reader.readline(size) + + def readlines(sizehint=None): + + return self.reader.readlines(sizehint) + def write(self,data): return self.writer.write(data) + def writelines(self,list): + + return self.writer.writelines(list) + def reset(self): self.reader.reset() @@ -290,6 +346,10 @@ class StreamReaderWriter: class StreamRecoder: + # Optional attributes set by the file wrappers below + data_encoding = 'unknown' + file_encoding = 'unknown' + def __init__(self,stream,encode,decode,Reader,Writer,errors='strict'): """ Creates a StreamRecoder instance which implements a two-way @@ -328,13 +388,34 @@ class StreamRecoder: data, bytesencoded = self.encode(data, self.errors) return data + def readline(self,size=None): + + if size is None: + data = self.reader.readline() + else: + data = self.reader.readline(size) + data, bytesencoded = self.encode(data, self.errors) + return data + + def readlines(self,sizehint=None): + + if sizehint is None: + data = self.reader.read() + else: + data = self.reader.read(sizehint) + data, bytesencoded = self.encode(data, self.errors) + return data.splitlines(1) + def write(self,data): data, bytesdecoded = self.decode(data, self.errors) return self.writer.write(data) - # .writelines(), .readline() and .readlines() ... see notes - # above. + def writelines(self,list): + + data = ''.join(list) + data, bytesdecoded = self.decode(data, self.errors) + return self.writer.write(data) def reset(self): @@ -380,33 +461,45 @@ def open(filename, mode, encoding=None, errors='strict', buffering=1): if encoding is None: return file (e,d,sr,sw) = lookup(encoding) - return StreamReaderWriter(file, sr, sw, errors) + srw = StreamReaderWriter(file, sr, sw, errors) + # Add attributes to simplify introspection + srw.encoding = encoding + return srw -def EncodedFile(file, input, output=None, errors='strict'): +def EncodedFile(file, data_encoding, file_encoding=None, errors='strict'): """ Return a wrapped version of file which provides transparent encoding translation. Strings written to the wrapped file are interpreted according - to the given input encoding and then written to the original - file as string using the output encoding. The intermediate - encoding will usually be Unicode but depends on the specified - codecs. + to the given data_encoding and then written to the original + file as string using file_encoding. The intermediate encoding + will usually be Unicode but depends on the specified codecs. + + Strings are read from the file using file_encoding and then + passed back to the caller as string using data_encoding. - If output is not given, it defaults to input. + If file_encoding is not given, it defaults to data_encoding. errors may be given to define the error handling. It defaults to 'strict' which causes ValueErrors to be raised in case an encoding error occurs. + data_encoding and file_encoding are added to the wrapped file + object as attributes .data_encoding and .file_encoding resp. + """ - if output is None: - output = input - encode, decode = lookup(input)[:2] - Reader, Writer = lookup(output)[2:] - return StreamRecoder(file, - encode,decode,Reader,Writer, - errors) + if file_encoding is None: + file_encoding = data_encoding + encode, decode = lookup(data_encoding)[:2] + Reader, Writer = lookup(file_encoding)[2:] + sr = StreamRecoder(file, + encode,decode,Reader,Writer, + errors) + # Add attributes to simplify introspection + sr.data_encoding = data_encoding + sr.file_encoding = file_encoding + return sr ### Tests @@ -414,5 +507,8 @@ if __name__ == '__main__': import sys - # Make stdout translate Latin-1 into Unicode-Escape - sys.stdout = EncodedFile(sys.stdout, 'latin-1', 'unicode-escape') + # Make stdout translate Latin-1 output into UTF-8 output + sys.stdout = EncodedFile(sys.stdout, 'latin-1', 'utf-8') + + # Have stdin translate Latin-1 input into UTF-8 input + sys.stdin = EncodedFile(sys.stdin, 'utf-8', 'latin-1') |