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752 lines
31 KiB
752 lines
31 KiB
import os
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import sys
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import math
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import time
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import logging
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import platform
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from .protocol import Protocol
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SOH = b'\x01'
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STX = b'\x02'
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EOT = b'\x04'
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ACK = b'\x06'
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NAK = b'\x15'
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CAN = b'\x18'
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CRC = b'\x43'
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USE_LENGTH_FIELD = 0b100000
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USE_DATE_FIELD = 0b010000
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USE_MODE_FIELD = 0b001000
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USE_SN_FIELD = 0b000100
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ALLOW_1K_PACKET = 0b000010
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ALLOW_YMODEM_G = 0b000001
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class Modem(Protocol):
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def __init__(self, reader, writer, mode='ymodem1k', program="rzsz"):
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self.logger = logging.getLogger('Modem')
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self.platform = sys.platform
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self.reader = reader
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self.writer = writer
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self.mode = mode
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'''
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YMODEM Header Information and Features
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_____________________________________________________________
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| Program | Length | Date | Mode | S/N | 1k-Blk | YMODEM-g |
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|___________|________|______|______|_____|________|__________|
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|Unix rz/sz | yes | yes | yes | no | yes | sb only |
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|___________|________|______|______|_____|________|__________|
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|VMS rb/sb | yes | no | no | no | yes | no |
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|___________|________|______|______|_____|________|__________|
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|Pro-YAM | yes | yes | no | yes | yes | yes |
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|___________|________|______|______|_____|________|__________|
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|CP/M YAM | no | no | no | no | yes | no |
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|___________|________|______|______|_____|________|__________|
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|KMD/IMP | ? | no | no | no | yes | no |
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|___________|________|______|______|_____|________|__________|
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'''
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try:
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self.program_features = dict(
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rzsz = USE_LENGTH_FIELD | USE_DATE_FIELD | USE_MODE_FIELD | ALLOW_1K_PACKET,
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rbsb = USE_LENGTH_FIELD | ALLOW_1K_PACKET,
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pyam = USE_LENGTH_FIELD | USE_DATE_FIELD | USE_SN_FIELD | ALLOW_1K_PACKET | ALLOW_YMODEM_G,
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cyam = ALLOW_1K_PACKET,
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kimp = ALLOW_1K_PACKET,
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)[program]
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except KeyError:
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raise ValueError("Invalid program specified: {}".format(program))
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def abort(self, count=2, timeout=60):
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for _ in range(count):
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self.writer.write(CAN, timeout)
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def send(self, file_paths, retry=10, timeout=10, callback=None):
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try:
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packet_size = dict(
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xmodem = 128,
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xmodem1k = 1024,
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ymodem = 128,
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# Not all but most programs support 1k length
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ymodem1k = (128, 1024)[(self.program_features & ALLOW_1K_PACKET) != 0],
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)[self.mode]
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except KeyError:
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raise ValueError("Invalid mode specified: {}.".format(self.mode))
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tasks = []
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for file_path in file_paths:
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tasks.append(
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{
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"path": file_path,
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"name": os.path.basename(file_path),
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"length": os.path.getsize(file_path),
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"mtime": os.path.getmtime(file_path)
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}
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)
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for task_index, task in enumerate(tasks):
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try:
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stream = open(task["path"], 'rb')
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except IOError as e:
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self.logger.debug("[Sender]: Cannot open the file: %s.", task)
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return False
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if self.mode.startswith("ymodem"):
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'''
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Info packet
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'''
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crc_mode = 0
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cancel_count = 0
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error_count = 0
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while True:
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# Blocking may occur here, the reader needs to have a timeout mechanism
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char = self.reader.read(1, timeout)
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if char == NAK:
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crc_mode = 0
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self.logger.debug("[Sender]: Received checksum request (NAK).")
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break
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elif char == CRC:
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crc_mode = 1
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self.logger.debug("[Sender]: Received CRC request (C/CRC).")
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break
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elif char == CAN:
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if cancel_count == 0:
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cancel_count += 1
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else:
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self.logger.debug("[Sender]: Cancel transfer (CAN).")
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return False
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else:
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self.logger.debug("[Sender]: No valid data read.")
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error_count += 1
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if error_count > retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Sender]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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header = self._make_send_header(packet_size, 0)
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# Required field: Name
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data = task["name"].encode("utf-8")
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# Optional field: Length
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if self.program_features & USE_LENGTH_FIELD:
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data += bytes(1)
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data += str(task["length"]).encode("utf-8")
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# Optional field: Modification Date
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# oct() has different representations of octal numbers in different versions of Python:
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# Python 2+: 0123456
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# Python 3+: 0o123456
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if self.program_features & USE_DATE_FIELD:
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mtime = oct(int(task["mtime"]))
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if mtime.startswith("0o"):
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data += (" " + mtime[2:]).encode("utf-8")
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else:
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data += (" " + mtime[1:]).encode("utf-8")
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# Optional field: Mode
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if self.program_features & USE_MODE_FIELD:
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if self.platform == "linux":
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data += (" " + oct(0x8000)).encode("utf-8")
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else:
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data += (" 0").encode("utf-8")
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# Optional field: Serial Number
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if self.program_features & USE_MODE_FIELD:
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data += (" 0").encode("utf-8")
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data = data.ljust(packet_size, b"\x00")
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checksum = self._make_send_checksum(crc_mode, data)
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error_count = 0
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while True:
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# Blocking may occur here, the writer needs to have a timeout mechanism
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self.writer.write(header + data + checksum)
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self.logger.debug("[Sender]: Info packet sent")
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# Blocking may occur here, the reader needs to have a timeout mechanism
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char = self.reader.read(1, timeout)
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if char == ACK:
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error_count = 0
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break
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else:
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error_count += 1
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self.logger.debug("[Sender]: No valid data read.")
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if error_count > retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Sender]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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'''
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Data packet
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'''
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crc_mode = 0
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cancel_count = 0
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error_count = 0
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while True:
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# Blocking may occur here, the reader needs to have a timeout mechanism
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char = self.reader.read(1, timeout)
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if char == NAK:
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crc_mode = 0
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self.logger.debug("[Sender]: Received checksum request (NAK).")
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break
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elif char == CRC:
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crc_mode = 1
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self.logger.debug("[Sender]: Received CRC request (C/CRC).")
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break
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elif char == CAN:
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if cancel_count == 0:
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cancel_count += 1
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else:
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self.logger.debug("[Sender]: Cancel transfer (CAN).")
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return False
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else:
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self.logger.debug("[Sender]: No valid data read.")
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error_count += 1
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if error_count > retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Sender]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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sequence = 1
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total_packet_count = math.ceil(task["length"] / packet_size)
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success_packet_count = 0
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error_packet_count = 0
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while True:
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try:
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data = stream.read(packet_size)
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except Exception as e:
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stream.close()
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self.logger.debug("[Sender]: Failed to read file.")
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return False
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if not data:
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self.logger.debug("[Sender]: Reached EOF")
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break
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header = self._make_send_header(packet_size, sequence)
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# fill with 1AH(^z)
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data = data.ljust(packet_size, b"\x1a")
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checksum = self._make_send_checksum(crc_mode, data)
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while True:
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# Blocking may occur here, the writer needs to have a timeout mechanism
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self.writer.write(header + data + checksum)
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self.logger.debug("[Sender]: Packet %d sent.", sequence)
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# Blocking may occur here, the reader needs to have a timeout mechanism
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char = self.reader.read(1, timeout)
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if char == ACK:
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success_packet_count += 1
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if callable(callback):
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callback(task_index, task["name"], total_packet_count, success_packet_count, error_packet_count)
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error_packet_count = 0
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break
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else:
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error_packet_count += 1
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self.logger.debug("[Sender]: Ready to resend packet %d.", sequence)
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if callable(callback):
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callback(task_index, task["name"], total_packet_count, success_packet_count, error_packet_count)
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if error_packet_count > retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Sender]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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sequence = (sequence + 1) % 0x100
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self.logger.debug("[Sender]: %d of %d - %s completed.", task_index+1, len(tasks), task["name"])
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'''
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EOT
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'''
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self.writer.write(EOT)
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self.logger.debug("[Sender]: EOT sent.")
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char = self.reader.read(1, timeout)
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if char != ACK:
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self.writer.write(EOT)
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self.logger.debug("[Sender]: EOT resent.")
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while True:
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char = self.reader.read(1, timeout)
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if char == ACK:
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break
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else:
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error_count += 1
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self.logger.debug("[Sender]: No valid data read.")
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if error_count > retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Sender]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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if stream:
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stream.close()
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'''
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batch end packet
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'''
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header = self._make_send_header(packet_size, 0)
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data = bytearray().ljust(packet_size, b"\x00")
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checksum = self._make_send_checksum(crc_mode, data)
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self.writer.write(header + data + checksum)
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self.logger.debug("[Sender]: Batch end packet sent.")
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return True
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def _make_send_header(self, packet_size, sequence):
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assert packet_size in (128, 1024), packet_size
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_bytes = []
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if packet_size == 128:
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_bytes.append(ord(SOH))
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elif packet_size == 1024:
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_bytes.append(ord(STX))
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_bytes.extend([sequence, 0xff - sequence])
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return bytearray(_bytes)
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def _make_send_checksum(self, crc_mode, data):
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_bytes = []
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if crc_mode:
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crc = self.calc_crc(data)
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_bytes.extend([crc >> 8, crc & 0xff])
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else:
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crc = self.calc_checksum(data)
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_bytes.append(crc)
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return bytearray(_bytes)
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def recv(self, folder_path, crc_mode=1, retry=10, timeout=10, delay=1, callback=None):
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# task index
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task_index = -1
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while True:
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task = {
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"name": "",
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"total_length": 0,
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"received_length": 0,
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"mtime": 0,
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"mode": 0,
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"sn": 0
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}
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'''
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Parse info packet
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'''
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if self.mode.startswith("ymodem"):
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char = 0
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cancel_count = 0
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error_count = 0
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while True:
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if error_count >= retry:
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self.abort(timeout=timeout)
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self.logger.debug("[Receiver]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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elif crc_mode and error_count < (retry // 2):
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if not self.writer.write(CRC):
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time.sleep(delay)
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error_count += 1
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self.logger.debug("[Receiver]: Failed to write CRC, sleep for {}s.".format(delay))
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else:
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crc_mode = 0
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if not self.writer.write(NAK):
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time.sleep(delay)
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error_count += 1
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self.logger.debug("[Receiver]: Failed to write NAK, sleep for {}s".format(delay))
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char = self.reader.read(1, timeout=3)
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if char == SOH or char == STX:
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break
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elif char == CAN:
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if cancel_count == 0:
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cancel_count += 1
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else:
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self.logger.debug("[Receiver]: Cancel transfer (CAN).")
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return False
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else:
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error_count += 1
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self.logger.debug("[Receiver]: No valid data received.")
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packet_size = 128
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cancel_count = 0
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error_count = 0
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while True:
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while True:
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if char == SOH:
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packet_size = 128
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self.logger.debug("[Receiver]: Set 128 bytes as packet size.")
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break
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elif char == STX:
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packet_size = 1024
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self.logger.debug("[Receiver]: Set 1024 bytes as packet size.")
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break
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elif char == CAN:
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if cancel_count == 0:
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cancel_count += 1
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else:
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self.logger.debug("[Receiver]: Cancel transfer (CAN).")
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return False
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else:
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error_count += 1
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self.logger.debug("[Receiver]: No valid data received.")
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if error_count > retry:
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self.abort(timeout=timeout)
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self.logger.debug("[Receiver]: Aborted, the number of errors has reached {}.".format(retry))
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return False
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error_count = 0
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seq1 = self.reader.read(1, timeout)
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if seq1:
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seq1 = ord(seq1)
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seq2 = self.reader.read(1, timeout)
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if seq2:
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seq2 = 0xff - ord(seq2)
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else:
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seq2 = None
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if not (seq1 == seq2 == 0):
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self.logger.debug("[Receiver]: Expected seq 0 but got (seq1 %r, seq2 %r).", seq1, seq2)
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# skip this packet
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self.reader.read(packet_size + 1 + crc_mode)
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self.logger.debug("[Receiver]: Dropped the broken packet.")
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else:
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data = self.reader.read(packet_size + 1 + crc_mode, timeout)
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if data and len(data) == (packet_size + 1 + crc_mode):
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valid, data = self._verify_recv_checksum(crc_mode, data)
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if valid:
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file_name = bytes.decode(data.split(b"\x00")[0], "utf-8")
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# batch end packet received
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if not file_name:
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self.logger.debug("[Receiver]: Received batch end packet.")
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self.writer.write(ACK)
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return True
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# info packet received
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else:
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self.logger.debug("[Receiver]: Received info packet.")
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task_index += 1
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task["name"] = file_name
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self.logger.debug("[Receiver]: File - {}".format(task["name"]))
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data = bytes.decode(data.split(b"\x00")[1], "utf-8")
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if self.program_features & USE_LENGTH_FIELD:
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space_index = data.find(" ")
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task["total_length"] = int(data if space_index == -1 else data[:space_index])
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self.logger.debug("[Receiver]: Size - {} bytes".format(task["total_length"]))
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data = data[space_index + 1:]
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if self.program_features & USE_DATE_FIELD:
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space_index = data.find(" ")
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task["mtime"] = int(data if space_index == -1 else data[:space_index], 8)
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self.logger.debug("[Receiver]: Mtime - {} seconds".format(task["mtime"]))
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data = data[space_index + 1:]
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if self.program_features & USE_MODE_FIELD:
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space_index = data.find(" ")
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task["mode"] = int(data if space_index == -1 else data[:space_index])
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self.logger.debug("[Receiver]: Mode - {}".format(task["mode"]))
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data = data[space_index + 1:]
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if self.program_features & USE_SN_FIELD:
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space_index = data.find(" ")
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task["sn"] = int(data if space_index == -1 else data[:space_index])
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self.logger.debug("[Receiver]: SN - {}".format(task["sn"]))
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self.writer.write(ACK)
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break
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# broken packet
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else:
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pass
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# bad read
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else:
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pass
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# Receive failed handler: ask for retransmission
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while True:
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if not self.reader.read(1, timeout=1):
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break
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self.writer.write(NAK)
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self.logger.debug("[Receiver]: Requesting retransmission (NAK).")
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char = self.reader.read(1, timeout)
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# create file in saving folder
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p = os.path.join(folder_path, task["name"])
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try:
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stream = open(p, "wb+")
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except IOError as e:
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self.logger.debug("[Receiver]: Cannot open the save path: %s.", p)
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return False
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'''
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Parse data packet
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'''
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char = 0
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cancel_count = 0
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error_count = 0
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while True:
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if error_count >= retry:
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self.abort(timeout=timeout)
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if stream:
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stream.close()
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self.logger.debug("[Receiver]: Aborted, the number of errors has reached {}.".format(retry))
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return False
|
|
elif crc_mode and error_count < (retry // 2):
|
|
if not self.writer.write(CRC):
|
|
self.logger.debug("[Receiver]: Failed to write CRC, sleep for {}s.".format(delay))
|
|
time.sleep(delay)
|
|
error_count += 1
|
|
else:
|
|
crc_mode = 0
|
|
if not self.writer.write(NAK):
|
|
self.logger.debug("[Receiver]: Failed to write NAK, sleep for {}s.".format(delay))
|
|
time.sleep(delay)
|
|
error_count += 1
|
|
|
|
char = self.reader.read(1, timeout=3)
|
|
if char == SOH or char == STX:
|
|
break
|
|
elif char == CAN:
|
|
if cancel_count == 0:
|
|
cancel_count += 1
|
|
else:
|
|
self.logger.debug("[Receiver]: Cancel transfer (CAN).")
|
|
return False
|
|
else:
|
|
error_count += 1
|
|
self.logger.debug("[Receiver]: No valid data read.")
|
|
|
|
|
|
eot_received = False
|
|
packet_size = 128
|
|
sequence = 1
|
|
cancel_count = 0
|
|
error_count = 0
|
|
success_packet_count = 0
|
|
error_packet_count = 0
|
|
while True:
|
|
while True:
|
|
if char == SOH:
|
|
packet_size = 128
|
|
self.logger.debug("[Receiver]: Set 128 bytes as packet size.")
|
|
break
|
|
elif char == STX:
|
|
packet_size = 1024
|
|
self.logger.debug("[Receiver]: Set 1024 bytes as packet size.")
|
|
break
|
|
elif char == EOT:
|
|
self.writer.write(ACK)
|
|
eot_received = True
|
|
self.logger.debug("[Receiver]: %d - %s completed.", task_index+1, task["name"])
|
|
break
|
|
elif char == CAN:
|
|
if cancel_count == 0:
|
|
cancel_count += 1
|
|
else:
|
|
if stream:
|
|
stream.close()
|
|
self.logger.debug("[Receiver]: Cancel transfer (CAN) at data packet {} (seq {}).".format(success_packet_count, sequence))
|
|
return False
|
|
else:
|
|
error_count += 1
|
|
self.logger.debug("[Receiver]: No valid data received.")
|
|
|
|
if error_count > retry:
|
|
self.abort(timeout=timeout)
|
|
if stream:
|
|
stream.close()
|
|
self.logger.debug("[Receiver]: Aborted, the number of errors has reached {}.".format(retry))
|
|
return False
|
|
|
|
if eot_received:
|
|
break
|
|
|
|
total_packet_count = math.ceil(task["total_length"] / packet_size)
|
|
|
|
seq1 = self.reader.read(1, timeout)
|
|
if seq1:
|
|
seq1 = ord(seq1)
|
|
seq2 = self.reader.read(1, timeout)
|
|
if seq2:
|
|
seq2 = 0xff - ord(seq2)
|
|
else:
|
|
seq2 = None
|
|
|
|
# Packet received in wrong number
|
|
if not (seq1 == seq2 == sequence):
|
|
self.logger.debug("[Receiver]: Expected seq %d but got (seq1 %r, seq2 %r).", sequence, seq1, seq2)
|
|
# skip this packet
|
|
self.reader.read(packet_size + 1 + crc_mode)
|
|
self.logger.debug("[Receiver]: Dropped the broken packet.")
|
|
|
|
# Packet received
|
|
else:
|
|
data = self.reader.read(packet_size + 1 + crc_mode, timeout)
|
|
|
|
if data and len(data) == (packet_size + 1 + crc_mode):
|
|
valid, data = self._verify_recv_checksum(crc_mode, data)
|
|
|
|
# Write the original data to the target file
|
|
if valid:
|
|
success_packet_count += 1
|
|
self.logger.debug("[Receiver]: Received data packet %d.", sequence)
|
|
|
|
valid_length = packet_size
|
|
|
|
# The last package adjusts the valid data length according to the file length
|
|
remaining_length = task["total_length"] - task["received_length"]
|
|
if (remaining_length > 0):
|
|
valid_length = min(valid_length, remaining_length)
|
|
data = data[:valid_length]
|
|
|
|
task["received_length"] += len(data)
|
|
|
|
try:
|
|
stream.write(data)
|
|
except Exception as e:
|
|
stream.close()
|
|
self.logger.debug("[Receiver]: Failed to write data packet %d to file.", sequence)
|
|
return False
|
|
|
|
self.logger.debug("[Receiver]: Successfully write data packet %d to file.", sequence)
|
|
|
|
if callable(callback):
|
|
callback(task_index, task["name"], total_packet_count, success_packet_count, error_packet_count)
|
|
|
|
self.writer.write(ACK)
|
|
|
|
sequence = (sequence + 1) % 0x100
|
|
char = self.reader.read(1, timeout)
|
|
continue
|
|
|
|
# broken packet
|
|
else:
|
|
error_packet_count += 1
|
|
self.logger.debug("[Receiver]: Received broken data packet.")
|
|
|
|
if callable(callback):
|
|
callback(task_index, task["name"], total_packet_count, success_packet_count, error_packet_count)
|
|
|
|
# bad read
|
|
else:
|
|
pass
|
|
|
|
# Receive failed handler: ask for retransmission
|
|
while True:
|
|
if not self.reader.read(1, timeout=1):
|
|
break
|
|
self.writer.write(NAK)
|
|
self.logger.debug("[Receiver]: Requested retransmission (NAK).")
|
|
|
|
char = self.reader.read(1, timeout)
|
|
|
|
if stream:
|
|
stream.close()
|
|
|
|
def _verify_recv_checksum(self, crc_mode, data):
|
|
if crc_mode:
|
|
_checksum = bytearray(data[-2:])
|
|
remote_sum = (_checksum[0] << 8) + _checksum[1]
|
|
data = data[:-2]
|
|
|
|
local_sum = self.calc_crc(data)
|
|
valid = bool(remote_sum == local_sum)
|
|
if not valid:
|
|
self.logger.debug("[Receiver]: CRC verification failed. Sender: %04x, Receiver: %04x.", remote_sum, local_sum)
|
|
else:
|
|
_checksum = bytearray([data[-1]])
|
|
remote_sum = _checksum[0]
|
|
data = data[:-1]
|
|
|
|
local_sum = self.calc_checksum(data)
|
|
valid = remote_sum == local_sum
|
|
if not valid:
|
|
self.logger.debug("[Receiver]: CRC verification failed. Sender: %02x, Receiver: %02x.", remote_sum, local_sum)
|
|
return valid, data
|
|
|
|
def calc_checksum(self, data, checksum=0):
|
|
if platform.python_version_tuple() >= ('3', '0', '0'):
|
|
return (sum(data) + checksum) % 256
|
|
else:
|
|
return (sum(map(ord, data)) + checksum) % 256
|
|
|
|
# For CRC algorithm
|
|
crctable = [
|
|
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
|
|
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
|
|
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
|
|
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
|
|
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
|
|
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
|
|
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
|
|
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
|
|
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
|
|
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
|
|
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
|
|
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
|
|
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
|
|
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
|
|
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
|
|
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
|
|
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
|
|
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
|
|
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
|
|
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
|
|
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
|
|
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
|
|
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
|
|
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
|
|
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
|
|
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
|
|
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
|
|
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
|
|
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
|
|
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
|
|
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
|
|
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
|
|
]
|
|
|
|
# CRC-16-CCITT
|
|
def calc_crc(self, data, crc=0):
|
|
for char in bytearray(data):
|
|
crctbl_idx = ((crc >> 8) ^ char) & 0xff
|
|
crc = ((crc << 8) ^ self.crctable[crctbl_idx]) & 0xffff
|
|
return crc & 0xffff
|
|
|