Viewing file:  hexlify_codec.py (3.59 KB) -rw-r--r--
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#! python
#
# This is a codec to create and decode hexdumps with spaces between characters. used by miniterm.
#
# This file is part of pySerial. https://github.com/pyserial/pyserial
# (C) 2015-2016 Chris Liechti <[email protected]>
#
# SPDX-License-Identifier: BSD-3-Clause
"""\
Python 'hex' Codec - 2-digit hex with spaces content transfer encoding.
Encode and decode may be a bit missleading at first sight...
The textual representation is a hex dump: e.g. "40 41"
The "encoded" data of this is the binary form, e.g. b"@A"
Therefore decoding is binary to text and thus converting binary data to hex dump.
"""
from __future__ import absolute_import
import codecs
import serial
try:
unicode
except (NameError, AttributeError):
unicode = str # for Python 3, pylint: disable=redefined-builtin,invalid-name
HEXDIGITS = '0123456789ABCDEF'
# Codec APIs
def hex_encode(data, errors='strict'):
"""'40 41 42' -> b'@ab'"""
return (serial.to_bytes([int(h, 16) for h in data.split()]), len(data))
def hex_decode(data, errors='strict'):
"""b'@ab' -> '40 41 42'"""
return (unicode(''.join('{:02X} '.format(ord(b)) for b in serial.iterbytes(data))), len(data))
class Codec(codecs.Codec):
def encode(self, data, errors='strict'):
"""'40 41 42' -> b'@ab'"""
return serial.to_bytes([int(h, 16) for h in data.split()])
def decode(self, data, errors='strict'):
"""b'@ab' -> '40 41 42'"""
return unicode(''.join('{:02X} '.format(ord(b)) for b in serial.iterbytes(data)))
class IncrementalEncoder(codecs.IncrementalEncoder):
"""Incremental hex encoder"""
def __init__(self, errors='strict'):
self.errors = errors
self.state = 0
def reset(self):
self.state = 0
def getstate(self):
return self.state
def setstate(self, state):
self.state = state
def encode(self, data, final=False):
"""\
Incremental encode, keep track of digits and emit a byte when a pair
of hex digits is found. The space is optional unless the error
handling is defined to be 'strict'.
"""
state = self.state
encoded = []
for c in data.upper():
if c in HEXDIGITS:
z = HEXDIGITS.index(c)
if state:
encoded.append(z + (state & 0xf0))
state = 0
else:
state = 0x100 + (z << 4)
elif c == ' ': # allow spaces to separate values
if state and self.errors == 'strict':
raise UnicodeError('odd number of hex digits')
state = 0
else:
if self.errors == 'strict':
raise UnicodeError('non-hex digit found: {!r}'.format(c))
self.state = state
return serial.to_bytes(encoded)
class IncrementalDecoder(codecs.IncrementalDecoder):
"""Incremental decoder"""
def decode(self, data, final=False):
return unicode(''.join('{:02X} '.format(ord(b)) for b in serial.iterbytes(data)))
class StreamWriter(Codec, codecs.StreamWriter):
"""Combination of hexlify codec and StreamWriter"""
class StreamReader(Codec, codecs.StreamReader):
"""Combination of hexlify codec and StreamReader"""
def getregentry():
"""encodings module API"""
return codecs.CodecInfo(
name='hexlify',
encode=hex_encode,
decode=hex_decode,
incrementalencoder=IncrementalEncoder,
incrementaldecoder=IncrementalDecoder,
streamwriter=StreamWriter,
streamreader=StreamReader,
#~ _is_text_encoding=True,
)
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