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##=============================================================================
#
# Copyright (C) 2003, 2004 Alessandro Duca
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
#=============================================================================
#
# $Id: yenc.py,v 1.2 2004/02/18 23:08:15 cvs Exp $
#
##=============================================================================
import sys
from cStringIO import StringIO
import _yenc
E_ERROR = 64
E_CRC32 = 65
E_PARMS = 66
class Error(Exception):
""" Class for specific yenc errors
"""
def __init__(self, value="", code=E_ERROR):
self.value = value
def __str__(self):
return "yenc.Error: %s\n" % self.value, self.value
def _checkArgsType(file_in, file_out, bytes):
""" Internal checkings, not to be used from outside this module
"""
if bytes < 0: raise Error("No. of bytes can't be negative", E_PARMS)
if type(file_in) == str:
if file_in == "-":
if bytes == 0: raise Error("No. of bytes is 0 or not \
specified while reading from stdin", E_PARMS)
file_in = sys.stdin
else: file_in = open(file_in,"rb")
if type(file_out) == str:
if file_out == "-": file_out = sys.stdout
else: file_out = open(file_out,"wb")
return file_in, file_out, bytes
def encode(file_in, file_out, bytes=0):
""" encode(file_in, file_out, bytes=0): write "bytes" encoded bytes from
file_in to file_out, if "bytes" is 0 encodes bytes until EOF
"""
file_in, file_out, bytes = _checkArgsType(file_in, file_out, bytes)
encoded, crc32 = _yenc.encode(file_in, file_out, bytes)
crc_hex = hex(crc32)[2:]
return encoded, crc_hex
def decode(file_in, file_out, bytes=0, crc_in=""):
""" decode(file_in, file_out, bytes=0): write "bytes" decoded bytes from
file_in to file_out, if "bytes" is 0 decodes bytes until EOF
"""
file_in, file_out, bytes = _checkArgsType(file_in, file_out, bytes)
decoded, crc32 = _yenc.decode(file_in, file_out, bytes)
crc_hex = hex(crc32)[2:]
if crc_in and not cmp(crc_hex,crc_in.lower()):
raise Error("crc32 error", E_CRC32)
else:
return decoded, crc_hex
class Encoder:
""" class Encoder: facility class for encoding one string at time
"""
def __init__(self, output_file = None):
self._buffer = StringIO()
self._column = 0
self._output_file = output_file
self._crc = -1
self._encoded = 0
self._terminated = 0
def __del__(self):
if(self._output_file):
self._output_file.flush()
self._output_file.close()
def feed(self, data):
""" Encode some data and write the encoded data
into the internal buffer
"""
if self._terminated:
raise IOError("Encoding already terminated")
encoded, self._crc, self._column = _yenc.encode_string(data,
self._crc, self._column)
self._encoded = self._encoded + len(encoded)
self._buffer.write(encoded)
return len(encoded)
def terminate(self):
""" Appends the terminal CRLF sequence to the encoded data
"""
self._terminated = 1
self._buffer.write("\r\n")
def flush(self):
""" Writes the content of the internal buffer on the file
passed as argument to the constructor
"""
if self._output_file:
self._output_file.write(self._buffer.getvalue())
self._buffer = StringIO()
else:
raise ValueError("Output file is 'None'")
def getEncoded(self):
""" Returns the data in the internal buffer
"""
if not self._output_file:
return self._buffer.getvalue()
else:
raise ValueError("Output file is not 'None'")
def getSize(self):
""" Returns the total number of encoded bytes (not the size of
the buffer)
"""
return self._encoded
def getCrc32(self):
""" Returns the calculated crc32 string for the clear
encoded data
"""
return "%08x" % (self._crc ^ -1)
class Decoder:
""" class Decoder: facility class for decoding one string at time
"""
def __init__(self, output_file = None):
self._buffer = StringIO()
self._escape = 0
self._output_file = output_file
self._crc = -1
self._decoded = 0
def __del__(self):
if(self._output_file):
self._output_file.flush()
self._output_file.close()
def feed(self, data):
""" Encode some data and write the encoded data
into the internal buffer
"""
decoded, self._crc, self._escape = _yenc.decode_string(data, self._crc, self._escape)
self._decoded = self._decoded + len(decoded)
self._buffer.write(decoded)
return len(decoded)
def flush(self):
""" Writes the content of the internal buffer on the file
passed as argument to the constructor
"""
if self._output_file:
self._output_file.write(self._buffer.getvalue())
self._buffer = StringIO()
else:
raise ValueError("Output file is 'None'")
def getDecoded(self):
""" Returns the data in the internal buffer
"""
if not self._output_file:
return self._buffer.getvalue()
else:
raise ValueError("Output file is not 'None'")
def getSize(self):
""" Returns the total number of decoded bytes (not the size of
the buffer)
"""
return self._decoded
def getCrc32(self):
""" Returns the calculated crc32 string for the decoded data
"""
return "%08x" % (self._crc ^ -1)
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