70 lines
1.5 KiB
Python
70 lines
1.5 KiB
Python
import ctypes
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import sys
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import os
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def crc_xmodem_update(crc, data):
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crc = ctypes.c_uint16(crc.value ^ data.value << 8)
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for i in range(0, 8):
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if crc.value & 0x8000:
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crc = ctypes.c_uint16((crc.value << 1) ^ 0x1021)
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else:
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crc = ctypes.c_uint16(crc.value << 1)
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return crc
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def do_crc(data):
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crc = ctypes.c_uint16(0)
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for idx, char in enumerate(data):
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crc = crc_xmodem_update(crc, ctypes.c_uint8(ord(char)))
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return crc.value
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def test_performance():
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data = str()
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fd = open("/dev/urandom")
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for i in range(0, 256):
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data += fd.read(1024)
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sys.stdout.write("*")
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sys.stdout.flush()
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print
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fd.close()
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print "%s" % do_crc(data)
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def test_algo():
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data = 'david'
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data = 'da'
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print "%x" % do_crc(data)
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def main():
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if sys.argv[1].endswith(".smc"):
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copy_header = True
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size = os.stat(sys.argv[1])[6]
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fd = open(sys.argv[1])
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if copy_header:
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fd.seek(512)
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size = size - 512
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addr = 0x0000
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step = 2 ** 15
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result = []
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while addr < size:
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try:
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block = fd.read(step)
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addr += step
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except:
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print "Done"
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break
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crc = do_crc(block)
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print "Bank: 0x%02x Addr: 0x%06x Block: 0x%04x CRC 0x%04x" % (addr / (2 ** 15), addr, addr / 512, ctypes.c_uint16(crc).value)
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result.append(hex(ctypes.c_uint16(crc).value))
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# print result
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if __name__ == '__main__':
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# test_algo()
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main()
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