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62 lines
2.1 KiB
Python
62 lines
2.1 KiB
Python
from usr.modules.common import Singleton
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class DtuProtocolData(Singleton):
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def __init__(self):
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self.crc_table = []
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self._create_table()
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def _create_table(self):
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poly = 0xEDB88320
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a = []
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for byte in range(256):
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crc = 0
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for bit in range(8):
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if (byte ^ crc) & 1:
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crc = (crc >> 1) ^ poly
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else:
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crc >>= 1
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byte >>= 1
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a.append(crc)
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self.crc_table = a
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def crc32(self, crc_string):
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value = 0xffffffff
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for ch in crc_string:
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value = self.crc_table[(ord(ch) ^ value) & 0xff] ^ (value >> 8)
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crc_value = str((-1 - value) & 0xffffffff)
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return crc_value
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def package_datas(self, msg_data, topic_id=False, request_msg=False):
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print(msg_data)
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if len(msg_data) == 0:
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if request_msg is not False:
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ret_bytes = "%s,%s,%d".encode('utf-8') % (str(request_msg), str(topic_id), len(msg_data))
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else:
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ret_bytes = "%s,%d".encode('utf-8') % (str(topic_id), len(msg_data))
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else:
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crc32_val = self.crc32(str(msg_data))
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msg_length = len(str(msg_data))
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if request_msg is not False:
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ret_bytes = "%s,%s,%s,%s,%s".encode('utf-8') % (str(request_msg), str(topic_id), str(msg_length), str(crc32_val), str(msg_data))
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else:
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ret_bytes = "%s,%s,%s,%s".encode('utf-8') % (str(topic_id), str(msg_length), str(crc32_val), str(msg_data))
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return ret_bytes
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def validate_length(self, data_len, msg_data, str_msg):
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if len(msg_data) < data_len:
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self.concat_buffer = str_msg
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self.wait_length = data_len - len(msg_data)
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print("wait length")
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print(self.wait_length)
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return False
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elif len(msg_data) > data_len:
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self.concat_buffer = ""
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self.wait_length = 0
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return False
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else:
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self.concat_buffer = ""
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self.wait_length = 0
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return True
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