mirror of https://github.com/acidanthera/audk.git
1102 lines
36 KiB
Python
1102 lines
36 KiB
Python
""" codecs -- Python Codec Registry, API and helpers.
|
|
|
|
|
|
Written by Marc-Andre Lemburg (mal@lemburg.com).
|
|
|
|
(c) Copyright CNRI, All Rights Reserved. NO WARRANTY.
|
|
|
|
"""#"
|
|
|
|
import __builtin__, sys
|
|
|
|
### Registry and builtin stateless codec functions
|
|
|
|
try:
|
|
from _codecs import *
|
|
except ImportError, why:
|
|
raise SystemError('Failed to load the builtin codecs: %s' % why)
|
|
|
|
__all__ = ["register", "lookup", "open", "EncodedFile", "BOM", "BOM_BE",
|
|
"BOM_LE", "BOM32_BE", "BOM32_LE", "BOM64_BE", "BOM64_LE",
|
|
"BOM_UTF8", "BOM_UTF16", "BOM_UTF16_LE", "BOM_UTF16_BE",
|
|
"BOM_UTF32", "BOM_UTF32_LE", "BOM_UTF32_BE",
|
|
"CodecInfo", "Codec", "IncrementalEncoder", "IncrementalDecoder",
|
|
"StreamReader", "StreamWriter",
|
|
"StreamReaderWriter", "StreamRecoder",
|
|
"getencoder", "getdecoder", "getincrementalencoder",
|
|
"getincrementaldecoder", "getreader", "getwriter",
|
|
"encode", "decode", "iterencode", "iterdecode",
|
|
"strict_errors", "ignore_errors", "replace_errors",
|
|
"xmlcharrefreplace_errors", "backslashreplace_errors",
|
|
"register_error", "lookup_error"]
|
|
|
|
### Constants
|
|
|
|
#
|
|
# Byte Order Mark (BOM = ZERO WIDTH NO-BREAK SPACE = U+FEFF)
|
|
# and its possible byte string values
|
|
# for UTF8/UTF16/UTF32 output and little/big endian machines
|
|
#
|
|
|
|
# UTF-8
|
|
BOM_UTF8 = '\xef\xbb\xbf'
|
|
|
|
# UTF-16, little endian
|
|
BOM_LE = BOM_UTF16_LE = '\xff\xfe'
|
|
|
|
# UTF-16, big endian
|
|
BOM_BE = BOM_UTF16_BE = '\xfe\xff'
|
|
|
|
# UTF-32, little endian
|
|
BOM_UTF32_LE = '\xff\xfe\x00\x00'
|
|
|
|
# UTF-32, big endian
|
|
BOM_UTF32_BE = '\x00\x00\xfe\xff'
|
|
|
|
if sys.byteorder == 'little':
|
|
|
|
# UTF-16, native endianness
|
|
BOM = BOM_UTF16 = BOM_UTF16_LE
|
|
|
|
# UTF-32, native endianness
|
|
BOM_UTF32 = BOM_UTF32_LE
|
|
|
|
else:
|
|
|
|
# UTF-16, native endianness
|
|
BOM = BOM_UTF16 = BOM_UTF16_BE
|
|
|
|
# UTF-32, native endianness
|
|
BOM_UTF32 = BOM_UTF32_BE
|
|
|
|
# Old broken names (don't use in new code)
|
|
BOM32_LE = BOM_UTF16_LE
|
|
BOM32_BE = BOM_UTF16_BE
|
|
BOM64_LE = BOM_UTF32_LE
|
|
BOM64_BE = BOM_UTF32_BE
|
|
|
|
|
|
### Codec base classes (defining the API)
|
|
|
|
class CodecInfo(tuple):
|
|
|
|
def __new__(cls, encode, decode, streamreader=None, streamwriter=None,
|
|
incrementalencoder=None, incrementaldecoder=None, name=None):
|
|
self = tuple.__new__(cls, (encode, decode, streamreader, streamwriter))
|
|
self.name = name
|
|
self.encode = encode
|
|
self.decode = decode
|
|
self.incrementalencoder = incrementalencoder
|
|
self.incrementaldecoder = incrementaldecoder
|
|
self.streamwriter = streamwriter
|
|
self.streamreader = streamreader
|
|
return self
|
|
|
|
def __repr__(self):
|
|
return "<%s.%s object for encoding %s at 0x%x>" % (self.__class__.__module__, self.__class__.__name__, self.name, id(self))
|
|
|
|
class Codec:
|
|
|
|
""" Defines the interface for stateless encoders/decoders.
|
|
|
|
The .encode()/.decode() methods may use different error
|
|
handling schemes by providing the errors argument. These
|
|
string values are predefined:
|
|
|
|
'strict' - raise a ValueError error (or a subclass)
|
|
'ignore' - ignore the character and continue with the next
|
|
'replace' - replace with a suitable replacement character;
|
|
Python will use the official U+FFFD REPLACEMENT
|
|
CHARACTER for the builtin Unicode codecs on
|
|
decoding and '?' on encoding.
|
|
'xmlcharrefreplace' - Replace with the appropriate XML
|
|
character reference (only for encoding).
|
|
'backslashreplace' - Replace with backslashed escape sequences
|
|
(only for encoding).
|
|
|
|
The set of allowed values can be extended via register_error.
|
|
|
|
"""
|
|
def encode(self, input, errors='strict'):
|
|
|
|
""" Encodes the object input and returns a tuple (output
|
|
object, length consumed).
|
|
|
|
errors defines the error handling to apply. It defaults to
|
|
'strict' handling.
|
|
|
|
The method may not store state in the Codec instance. Use
|
|
StreamCodec for codecs which have to keep state in order to
|
|
make encoding/decoding efficient.
|
|
|
|
The encoder must be able to handle zero length input and
|
|
return an empty object of the output object type in this
|
|
situation.
|
|
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def decode(self, input, errors='strict'):
|
|
|
|
""" Decodes the object input and returns a tuple (output
|
|
object, length consumed).
|
|
|
|
input must be an object which provides the bf_getreadbuf
|
|
buffer slot. Python strings, buffer objects and memory
|
|
mapped files are examples of objects providing this slot.
|
|
|
|
errors defines the error handling to apply. It defaults to
|
|
'strict' handling.
|
|
|
|
The method may not store state in the Codec instance. Use
|
|
StreamCodec for codecs which have to keep state in order to
|
|
make encoding/decoding efficient.
|
|
|
|
The decoder must be able to handle zero length input and
|
|
return an empty object of the output object type in this
|
|
situation.
|
|
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
class IncrementalEncoder(object):
|
|
"""
|
|
An IncrementalEncoder encodes an input in multiple steps. The input can be
|
|
passed piece by piece to the encode() method. The IncrementalEncoder remembers
|
|
the state of the Encoding process between calls to encode().
|
|
"""
|
|
def __init__(self, errors='strict'):
|
|
"""
|
|
Creates an IncrementalEncoder instance.
|
|
|
|
The IncrementalEncoder may use different error handling schemes by
|
|
providing the errors keyword argument. See the module docstring
|
|
for a list of possible values.
|
|
"""
|
|
self.errors = errors
|
|
self.buffer = ""
|
|
|
|
def encode(self, input, final=False):
|
|
"""
|
|
Encodes input and returns the resulting object.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def reset(self):
|
|
"""
|
|
Resets the encoder to the initial state.
|
|
"""
|
|
|
|
def getstate(self):
|
|
"""
|
|
Return the current state of the encoder.
|
|
"""
|
|
return 0
|
|
|
|
def setstate(self, state):
|
|
"""
|
|
Set the current state of the encoder. state must have been
|
|
returned by getstate().
|
|
"""
|
|
|
|
class BufferedIncrementalEncoder(IncrementalEncoder):
|
|
"""
|
|
This subclass of IncrementalEncoder can be used as the baseclass for an
|
|
incremental encoder if the encoder must keep some of the output in a
|
|
buffer between calls to encode().
|
|
"""
|
|
def __init__(self, errors='strict'):
|
|
IncrementalEncoder.__init__(self, errors)
|
|
self.buffer = "" # unencoded input that is kept between calls to encode()
|
|
|
|
def _buffer_encode(self, input, errors, final):
|
|
# Overwrite this method in subclasses: It must encode input
|
|
# and return an (output, length consumed) tuple
|
|
raise NotImplementedError
|
|
|
|
def encode(self, input, final=False):
|
|
# encode input (taking the buffer into account)
|
|
data = self.buffer + input
|
|
(result, consumed) = self._buffer_encode(data, self.errors, final)
|
|
# keep unencoded input until the next call
|
|
self.buffer = data[consumed:]
|
|
return result
|
|
|
|
def reset(self):
|
|
IncrementalEncoder.reset(self)
|
|
self.buffer = ""
|
|
|
|
def getstate(self):
|
|
return self.buffer or 0
|
|
|
|
def setstate(self, state):
|
|
self.buffer = state or ""
|
|
|
|
class IncrementalDecoder(object):
|
|
"""
|
|
An IncrementalDecoder decodes an input in multiple steps. The input can be
|
|
passed piece by piece to the decode() method. The IncrementalDecoder
|
|
remembers the state of the decoding process between calls to decode().
|
|
"""
|
|
def __init__(self, errors='strict'):
|
|
"""
|
|
Creates a IncrementalDecoder instance.
|
|
|
|
The IncrementalDecoder may use different error handling schemes by
|
|
providing the errors keyword argument. See the module docstring
|
|
for a list of possible values.
|
|
"""
|
|
self.errors = errors
|
|
|
|
def decode(self, input, final=False):
|
|
"""
|
|
Decodes input and returns the resulting object.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def reset(self):
|
|
"""
|
|
Resets the decoder to the initial state.
|
|
"""
|
|
|
|
def getstate(self):
|
|
"""
|
|
Return the current state of the decoder.
|
|
|
|
This must be a (buffered_input, additional_state_info) tuple.
|
|
buffered_input must be a bytes object containing bytes that
|
|
were passed to decode() that have not yet been converted.
|
|
additional_state_info must be a non-negative integer
|
|
representing the state of the decoder WITHOUT yet having
|
|
processed the contents of buffered_input. In the initial state
|
|
and after reset(), getstate() must return (b"", 0).
|
|
"""
|
|
return (b"", 0)
|
|
|
|
def setstate(self, state):
|
|
"""
|
|
Set the current state of the decoder.
|
|
|
|
state must have been returned by getstate(). The effect of
|
|
setstate((b"", 0)) must be equivalent to reset().
|
|
"""
|
|
|
|
class BufferedIncrementalDecoder(IncrementalDecoder):
|
|
"""
|
|
This subclass of IncrementalDecoder can be used as the baseclass for an
|
|
incremental decoder if the decoder must be able to handle incomplete byte
|
|
sequences.
|
|
"""
|
|
def __init__(self, errors='strict'):
|
|
IncrementalDecoder.__init__(self, errors)
|
|
self.buffer = "" # undecoded input that is kept between calls to decode()
|
|
|
|
def _buffer_decode(self, input, errors, final):
|
|
# Overwrite this method in subclasses: It must decode input
|
|
# and return an (output, length consumed) tuple
|
|
raise NotImplementedError
|
|
|
|
def decode(self, input, final=False):
|
|
# decode input (taking the buffer into account)
|
|
data = self.buffer + input
|
|
(result, consumed) = self._buffer_decode(data, self.errors, final)
|
|
# keep undecoded input until the next call
|
|
self.buffer = data[consumed:]
|
|
return result
|
|
|
|
def reset(self):
|
|
IncrementalDecoder.reset(self)
|
|
self.buffer = ""
|
|
|
|
def getstate(self):
|
|
# additional state info is always 0
|
|
return (self.buffer, 0)
|
|
|
|
def setstate(self, state):
|
|
# ignore additional state info
|
|
self.buffer = state[0]
|
|
|
|
#
|
|
# The StreamWriter and StreamReader class provide generic working
|
|
# interfaces which can be used to implement new encoding submodules
|
|
# very easily. See encodings/utf_8.py for an example on how this is
|
|
# done.
|
|
#
|
|
|
|
class StreamWriter(Codec):
|
|
|
|
def __init__(self, stream, errors='strict'):
|
|
|
|
""" Creates a StreamWriter instance.
|
|
|
|
stream must be a file-like object open for writing
|
|
(binary) data.
|
|
|
|
The StreamWriter may use different error handling
|
|
schemes by providing the errors keyword argument. These
|
|
parameters are predefined:
|
|
|
|
'strict' - raise a ValueError (or a subclass)
|
|
'ignore' - ignore the character and continue with the next
|
|
'replace'- replace with a suitable replacement character
|
|
'xmlcharrefreplace' - Replace with the appropriate XML
|
|
character reference.
|
|
'backslashreplace' - Replace with backslashed escape
|
|
sequences (only for encoding).
|
|
|
|
The set of allowed parameter values can be extended via
|
|
register_error.
|
|
"""
|
|
self.stream = stream
|
|
self.errors = errors
|
|
|
|
def write(self, object):
|
|
|
|
""" Writes the object's contents encoded to self.stream.
|
|
"""
|
|
data, consumed = self.encode(object, self.errors)
|
|
self.stream.write(data)
|
|
|
|
def writelines(self, list):
|
|
|
|
""" Writes the concatenated list of strings to the stream
|
|
using .write().
|
|
"""
|
|
self.write(''.join(list))
|
|
|
|
def reset(self):
|
|
|
|
""" Flushes and resets the codec buffers used for keeping state.
|
|
|
|
Calling this method should ensure that the data on the
|
|
output is put into a clean state, that allows appending
|
|
of new fresh data without having to rescan the whole
|
|
stream to recover state.
|
|
|
|
"""
|
|
pass
|
|
|
|
def seek(self, offset, whence=0):
|
|
self.stream.seek(offset, whence)
|
|
if whence == 0 and offset == 0:
|
|
self.reset()
|
|
|
|
def __getattr__(self, name,
|
|
getattr=getattr):
|
|
|
|
""" Inherit all other methods from the underlying stream.
|
|
"""
|
|
return getattr(self.stream, name)
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, type, value, tb):
|
|
self.stream.close()
|
|
|
|
###
|
|
|
|
class StreamReader(Codec):
|
|
|
|
def __init__(self, stream, errors='strict'):
|
|
|
|
""" Creates a StreamReader instance.
|
|
|
|
stream must be a file-like object open for reading
|
|
(binary) data.
|
|
|
|
The StreamReader may use different error handling
|
|
schemes by providing the errors keyword argument. These
|
|
parameters are predefined:
|
|
|
|
'strict' - raise a ValueError (or a subclass)
|
|
'ignore' - ignore the character and continue with the next
|
|
'replace'- replace with a suitable replacement character;
|
|
|
|
The set of allowed parameter values can be extended via
|
|
register_error.
|
|
"""
|
|
self.stream = stream
|
|
self.errors = errors
|
|
self.bytebuffer = ""
|
|
# For str->str decoding this will stay a str
|
|
# For str->unicode decoding the first read will promote it to unicode
|
|
self.charbuffer = ""
|
|
self.linebuffer = None
|
|
|
|
def decode(self, input, errors='strict'):
|
|
raise NotImplementedError
|
|
|
|
def read(self, size=-1, chars=-1, firstline=False):
|
|
|
|
""" Decodes data from the stream self.stream and returns the
|
|
resulting object.
|
|
|
|
chars indicates the number of characters to read from the
|
|
stream. read() will never return more than chars
|
|
characters, but it might return less, if there are not enough
|
|
characters available.
|
|
|
|
size indicates the approximate maximum number of bytes to
|
|
read from the stream for decoding purposes. The decoder
|
|
can modify this setting as appropriate. The default value
|
|
-1 indicates to read and decode as much as possible. size
|
|
is intended to prevent having to decode huge files in one
|
|
step.
|
|
|
|
If firstline is true, and a UnicodeDecodeError happens
|
|
after the first line terminator in the input only the first line
|
|
will be returned, the rest of the input will be kept until the
|
|
next call to read().
|
|
|
|
The method should use a greedy read strategy meaning that
|
|
it should read as much data as is allowed within the
|
|
definition of the encoding and the given size, e.g. if
|
|
optional encoding endings or state markers are available
|
|
on the stream, these should be read too.
|
|
"""
|
|
# If we have lines cached, first merge them back into characters
|
|
if self.linebuffer:
|
|
self.charbuffer = "".join(self.linebuffer)
|
|
self.linebuffer = None
|
|
|
|
# read until we get the required number of characters (if available)
|
|
while True:
|
|
# can the request be satisfied from the character buffer?
|
|
if chars >= 0:
|
|
if len(self.charbuffer) >= chars:
|
|
break
|
|
elif size >= 0:
|
|
if len(self.charbuffer) >= size:
|
|
break
|
|
# we need more data
|
|
if size < 0:
|
|
newdata = self.stream.read()
|
|
else:
|
|
newdata = self.stream.read(size)
|
|
# decode bytes (those remaining from the last call included)
|
|
data = self.bytebuffer + newdata
|
|
try:
|
|
newchars, decodedbytes = self.decode(data, self.errors)
|
|
except UnicodeDecodeError, exc:
|
|
if firstline:
|
|
newchars, decodedbytes = self.decode(data[:exc.start], self.errors)
|
|
lines = newchars.splitlines(True)
|
|
if len(lines)<=1:
|
|
raise
|
|
else:
|
|
raise
|
|
# keep undecoded bytes until the next call
|
|
self.bytebuffer = data[decodedbytes:]
|
|
# put new characters in the character buffer
|
|
self.charbuffer += newchars
|
|
# there was no data available
|
|
if not newdata:
|
|
break
|
|
if chars < 0:
|
|
# Return everything we've got
|
|
result = self.charbuffer
|
|
self.charbuffer = ""
|
|
else:
|
|
# Return the first chars characters
|
|
result = self.charbuffer[:chars]
|
|
self.charbuffer = self.charbuffer[chars:]
|
|
return result
|
|
|
|
def readline(self, size=None, keepends=True):
|
|
|
|
""" Read one line from the input stream and return the
|
|
decoded data.
|
|
|
|
size, if given, is passed as size argument to the
|
|
read() method.
|
|
|
|
"""
|
|
# If we have lines cached from an earlier read, return
|
|
# them unconditionally
|
|
if self.linebuffer:
|
|
line = self.linebuffer[0]
|
|
del self.linebuffer[0]
|
|
if len(self.linebuffer) == 1:
|
|
# revert to charbuffer mode; we might need more data
|
|
# next time
|
|
self.charbuffer = self.linebuffer[0]
|
|
self.linebuffer = None
|
|
if not keepends:
|
|
line = line.splitlines(False)[0]
|
|
return line
|
|
|
|
readsize = size or 72
|
|
line = ""
|
|
# If size is given, we call read() only once
|
|
while True:
|
|
data = self.read(readsize, firstline=True)
|
|
if data:
|
|
# If we're at a "\r" read one extra character (which might
|
|
# be a "\n") to get a proper line ending. If the stream is
|
|
# temporarily exhausted we return the wrong line ending.
|
|
if data.endswith("\r"):
|
|
data += self.read(size=1, chars=1)
|
|
|
|
line += data
|
|
lines = line.splitlines(True)
|
|
if lines:
|
|
if len(lines) > 1:
|
|
# More than one line result; the first line is a full line
|
|
# to return
|
|
line = lines[0]
|
|
del lines[0]
|
|
if len(lines) > 1:
|
|
# cache the remaining lines
|
|
lines[-1] += self.charbuffer
|
|
self.linebuffer = lines
|
|
self.charbuffer = None
|
|
else:
|
|
# only one remaining line, put it back into charbuffer
|
|
self.charbuffer = lines[0] + self.charbuffer
|
|
if not keepends:
|
|
line = line.splitlines(False)[0]
|
|
break
|
|
line0withend = lines[0]
|
|
line0withoutend = lines[0].splitlines(False)[0]
|
|
if line0withend != line0withoutend: # We really have a line end
|
|
# Put the rest back together and keep it until the next call
|
|
self.charbuffer = "".join(lines[1:]) + self.charbuffer
|
|
if keepends:
|
|
line = line0withend
|
|
else:
|
|
line = line0withoutend
|
|
break
|
|
# we didn't get anything or this was our only try
|
|
if not data or size is not None:
|
|
if line and not keepends:
|
|
line = line.splitlines(False)[0]
|
|
break
|
|
if readsize<8000:
|
|
readsize *= 2
|
|
return line
|
|
|
|
def readlines(self, sizehint=None, keepends=True):
|
|
|
|
""" 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 ignored since there is no efficient
|
|
way to finding the true end-of-line.
|
|
|
|
"""
|
|
data = self.read()
|
|
return data.splitlines(keepends)
|
|
|
|
def reset(self):
|
|
|
|
""" Resets the codec buffers used for keeping state.
|
|
|
|
Note that no stream repositioning should take place.
|
|
This method is primarily intended to be able to recover
|
|
from decoding errors.
|
|
|
|
"""
|
|
self.bytebuffer = ""
|
|
self.charbuffer = u""
|
|
self.linebuffer = None
|
|
|
|
def seek(self, offset, whence=0):
|
|
""" Set the input stream's current position.
|
|
|
|
Resets the codec buffers used for keeping state.
|
|
"""
|
|
self.stream.seek(offset, whence)
|
|
self.reset()
|
|
|
|
def next(self):
|
|
|
|
""" Return the next decoded line from the input stream."""
|
|
line = self.readline()
|
|
if line:
|
|
return line
|
|
raise StopIteration
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def __getattr__(self, name,
|
|
getattr=getattr):
|
|
|
|
""" Inherit all other methods from the underlying stream.
|
|
"""
|
|
return getattr(self.stream, name)
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, type, value, tb):
|
|
self.stream.close()
|
|
|
|
###
|
|
|
|
class StreamReaderWriter:
|
|
|
|
""" StreamReaderWriter instances allow wrapping streams which
|
|
work in both read and write modes.
|
|
|
|
The design is such that one can use the factory functions
|
|
returned by the codec.lookup() function to construct the
|
|
instance.
|
|
|
|
"""
|
|
# Optional attributes set by the file wrappers below
|
|
encoding = 'unknown'
|
|
|
|
def __init__(self, stream, Reader, Writer, errors='strict'):
|
|
|
|
""" Creates a StreamReaderWriter instance.
|
|
|
|
stream must be a Stream-like object.
|
|
|
|
Reader, Writer must be factory functions or classes
|
|
providing the StreamReader, StreamWriter interface resp.
|
|
|
|
Error handling is done in the same way as defined for the
|
|
StreamWriter/Readers.
|
|
|
|
"""
|
|
self.stream = stream
|
|
self.reader = Reader(stream, errors)
|
|
self.writer = Writer(stream, errors)
|
|
self.errors = errors
|
|
|
|
def read(self, size=-1):
|
|
|
|
return self.reader.read(size)
|
|
|
|
def readline(self, size=None):
|
|
|
|
return self.reader.readline(size)
|
|
|
|
def readlines(self, sizehint=None):
|
|
|
|
return self.reader.readlines(sizehint)
|
|
|
|
def next(self):
|
|
|
|
""" Return the next decoded line from the input stream."""
|
|
return self.reader.next()
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def write(self, data):
|
|
|
|
return self.writer.write(data)
|
|
|
|
def writelines(self, list):
|
|
|
|
return self.writer.writelines(list)
|
|
|
|
def reset(self):
|
|
|
|
self.reader.reset()
|
|
self.writer.reset()
|
|
|
|
def seek(self, offset, whence=0):
|
|
self.stream.seek(offset, whence)
|
|
self.reader.reset()
|
|
if whence == 0 and offset == 0:
|
|
self.writer.reset()
|
|
|
|
def __getattr__(self, name,
|
|
getattr=getattr):
|
|
|
|
""" Inherit all other methods from the underlying stream.
|
|
"""
|
|
return getattr(self.stream, name)
|
|
|
|
# these are needed to make "with codecs.open(...)" work properly
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, type, value, tb):
|
|
self.stream.close()
|
|
|
|
###
|
|
|
|
class StreamRecoder:
|
|
|
|
""" StreamRecoder instances provide a frontend - backend
|
|
view of encoding data.
|
|
|
|
They use the complete set of APIs returned by the
|
|
codecs.lookup() function to implement their task.
|
|
|
|
Data written to the stream is first decoded into an
|
|
intermediate format (which is dependent on the given codec
|
|
combination) and then written to the stream using an instance
|
|
of the provided Writer class.
|
|
|
|
In the other direction, data is read from the stream using a
|
|
Reader instance and then return encoded data to the caller.
|
|
|
|
"""
|
|
# 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
|
|
conversion: encode and decode work on the frontend (the
|
|
input to .read() and output of .write()) while
|
|
Reader and Writer work on the backend (reading and
|
|
writing to the stream).
|
|
|
|
You can use these objects to do transparent direct
|
|
recodings from e.g. latin-1 to utf-8 and back.
|
|
|
|
stream must be a file-like object.
|
|
|
|
encode, decode must adhere to the Codec interface, Reader,
|
|
Writer must be factory functions or classes providing the
|
|
StreamReader, StreamWriter interface resp.
|
|
|
|
encode and decode are needed for the frontend translation,
|
|
Reader and Writer for the backend translation. Unicode is
|
|
used as intermediate encoding.
|
|
|
|
Error handling is done in the same way as defined for the
|
|
StreamWriter/Readers.
|
|
|
|
"""
|
|
self.stream = stream
|
|
self.encode = encode
|
|
self.decode = decode
|
|
self.reader = Reader(stream, errors)
|
|
self.writer = Writer(stream, errors)
|
|
self.errors = errors
|
|
|
|
def read(self, size=-1):
|
|
|
|
data = self.reader.read(size)
|
|
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):
|
|
|
|
data = self.reader.read()
|
|
data, bytesencoded = self.encode(data, self.errors)
|
|
return data.splitlines(1)
|
|
|
|
def next(self):
|
|
|
|
""" Return the next decoded line from the input stream."""
|
|
data = self.reader.next()
|
|
data, bytesencoded = self.encode(data, self.errors)
|
|
return data
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def write(self, data):
|
|
|
|
data, bytesdecoded = self.decode(data, self.errors)
|
|
return self.writer.write(data)
|
|
|
|
def writelines(self, list):
|
|
|
|
data = ''.join(list)
|
|
data, bytesdecoded = self.decode(data, self.errors)
|
|
return self.writer.write(data)
|
|
|
|
def reset(self):
|
|
|
|
self.reader.reset()
|
|
self.writer.reset()
|
|
|
|
def __getattr__(self, name,
|
|
getattr=getattr):
|
|
|
|
""" Inherit all other methods from the underlying stream.
|
|
"""
|
|
return getattr(self.stream, name)
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, type, value, tb):
|
|
self.stream.close()
|
|
|
|
### Shortcuts
|
|
|
|
def open(filename, mode='rb', encoding=None, errors='strict', buffering=1):
|
|
|
|
""" Open an encoded file using the given mode and return
|
|
a wrapped version providing transparent encoding/decoding.
|
|
|
|
Note: The wrapped version will only accept the object format
|
|
defined by the codecs, i.e. Unicode objects for most builtin
|
|
codecs. Output is also codec dependent and will usually be
|
|
Unicode as well.
|
|
|
|
Files are always opened in binary mode, even if no binary mode
|
|
was specified. This is done to avoid data loss due to encodings
|
|
using 8-bit values. The default file mode is 'rb' meaning to
|
|
open the file in binary read mode.
|
|
|
|
encoding specifies the encoding which is to be used for the
|
|
file.
|
|
|
|
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.
|
|
|
|
buffering has the same meaning as for the builtin open() API.
|
|
It defaults to line buffered.
|
|
|
|
The returned wrapped file object provides an extra attribute
|
|
.encoding which allows querying the used encoding. This
|
|
attribute is only available if an encoding was specified as
|
|
parameter.
|
|
|
|
"""
|
|
if encoding is not None:
|
|
if 'U' in mode:
|
|
# No automatic conversion of '\n' is done on reading and writing
|
|
mode = mode.strip().replace('U', '')
|
|
if mode[:1] not in set('rwa'):
|
|
mode = 'r' + mode
|
|
if 'b' not in mode:
|
|
# Force opening of the file in binary mode
|
|
mode = mode + 'b'
|
|
file = __builtin__.open(filename, mode, buffering)
|
|
if encoding is None:
|
|
return file
|
|
info = lookup(encoding)
|
|
srw = StreamReaderWriter(file, info.streamreader, info.streamwriter, errors)
|
|
# Add attributes to simplify introspection
|
|
srw.encoding = encoding
|
|
return srw
|
|
|
|
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 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 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.
|
|
|
|
The returned wrapped file object provides two extra attributes
|
|
.data_encoding and .file_encoding which reflect the given
|
|
parameters of the same name. The attributes can be used for
|
|
introspection by Python programs.
|
|
|
|
"""
|
|
if file_encoding is None:
|
|
file_encoding = data_encoding
|
|
data_info = lookup(data_encoding)
|
|
file_info = lookup(file_encoding)
|
|
sr = StreamRecoder(file, data_info.encode, data_info.decode,
|
|
file_info.streamreader, file_info.streamwriter, errors)
|
|
# Add attributes to simplify introspection
|
|
sr.data_encoding = data_encoding
|
|
sr.file_encoding = file_encoding
|
|
return sr
|
|
|
|
### Helpers for codec lookup
|
|
|
|
def getencoder(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its encoder function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found.
|
|
|
|
"""
|
|
return lookup(encoding).encode
|
|
|
|
def getdecoder(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its decoder function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found.
|
|
|
|
"""
|
|
return lookup(encoding).decode
|
|
|
|
def getincrementalencoder(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its IncrementalEncoder class or factory function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found
|
|
or the codecs doesn't provide an incremental encoder.
|
|
|
|
"""
|
|
encoder = lookup(encoding).incrementalencoder
|
|
if encoder is None:
|
|
raise LookupError(encoding)
|
|
return encoder
|
|
|
|
def getincrementaldecoder(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its IncrementalDecoder class or factory function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found
|
|
or the codecs doesn't provide an incremental decoder.
|
|
|
|
"""
|
|
decoder = lookup(encoding).incrementaldecoder
|
|
if decoder is None:
|
|
raise LookupError(encoding)
|
|
return decoder
|
|
|
|
def getreader(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its StreamReader class or factory function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found.
|
|
|
|
"""
|
|
return lookup(encoding).streamreader
|
|
|
|
def getwriter(encoding):
|
|
|
|
""" Lookup up the codec for the given encoding and return
|
|
its StreamWriter class or factory function.
|
|
|
|
Raises a LookupError in case the encoding cannot be found.
|
|
|
|
"""
|
|
return lookup(encoding).streamwriter
|
|
|
|
def iterencode(iterator, encoding, errors='strict', **kwargs):
|
|
"""
|
|
Encoding iterator.
|
|
|
|
Encodes the input strings from the iterator using a IncrementalEncoder.
|
|
|
|
errors and kwargs are passed through to the IncrementalEncoder
|
|
constructor.
|
|
"""
|
|
encoder = getincrementalencoder(encoding)(errors, **kwargs)
|
|
for input in iterator:
|
|
output = encoder.encode(input)
|
|
if output:
|
|
yield output
|
|
output = encoder.encode("", True)
|
|
if output:
|
|
yield output
|
|
|
|
def iterdecode(iterator, encoding, errors='strict', **kwargs):
|
|
"""
|
|
Decoding iterator.
|
|
|
|
Decodes the input strings from the iterator using a IncrementalDecoder.
|
|
|
|
errors and kwargs are passed through to the IncrementalDecoder
|
|
constructor.
|
|
"""
|
|
decoder = getincrementaldecoder(encoding)(errors, **kwargs)
|
|
for input in iterator:
|
|
output = decoder.decode(input)
|
|
if output:
|
|
yield output
|
|
output = decoder.decode("", True)
|
|
if output:
|
|
yield output
|
|
|
|
### Helpers for charmap-based codecs
|
|
|
|
def make_identity_dict(rng):
|
|
|
|
""" make_identity_dict(rng) -> dict
|
|
|
|
Return a dictionary where elements of the rng sequence are
|
|
mapped to themselves.
|
|
|
|
"""
|
|
res = {}
|
|
for i in rng:
|
|
res[i]=i
|
|
return res
|
|
|
|
def make_encoding_map(decoding_map):
|
|
|
|
""" Creates an encoding map from a decoding map.
|
|
|
|
If a target mapping in the decoding map occurs multiple
|
|
times, then that target is mapped to None (undefined mapping),
|
|
causing an exception when encountered by the charmap codec
|
|
during translation.
|
|
|
|
One example where this happens is cp875.py which decodes
|
|
multiple character to \\u001a.
|
|
|
|
"""
|
|
m = {}
|
|
for k,v in decoding_map.items():
|
|
if not v in m:
|
|
m[v] = k
|
|
else:
|
|
m[v] = None
|
|
return m
|
|
|
|
### error handlers
|
|
|
|
try:
|
|
strict_errors = lookup_error("strict")
|
|
ignore_errors = lookup_error("ignore")
|
|
replace_errors = lookup_error("replace")
|
|
xmlcharrefreplace_errors = lookup_error("xmlcharrefreplace")
|
|
backslashreplace_errors = lookup_error("backslashreplace")
|
|
except LookupError:
|
|
# In --disable-unicode builds, these error handler are missing
|
|
strict_errors = None
|
|
ignore_errors = None
|
|
replace_errors = None
|
|
xmlcharrefreplace_errors = None
|
|
backslashreplace_errors = None
|
|
|
|
# Tell modulefinder that using codecs probably needs the encodings
|
|
# package
|
|
_false = 0
|
|
if _false:
|
|
import encodings
|
|
|
|
### Tests
|
|
|
|
if __name__ == '__main__':
|
|
|
|
# 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')
|