30 lines
612 B
Python
30 lines
612 B
Python
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import binascii
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def CRC32(buf):
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return binascii.crc32(buf).to_bytes(4, byteorder='big')
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def LENGTH(buf):
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return len(buf).to_bytes(4, byteorder='big')
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def insert_crc(i_filename, o_filename=None):
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f = open(i_filename, 'rb+')
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fdata = f.read()
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fcrc = CRC32(fdata)
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flength = LENGTH(fdata)
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f.close()
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# Write the CRC32 in big endian at the end of the file
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if o_filename is None:
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f = open(i_filename, 'wb')
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f.write(fdata)
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f.write(fcrc)
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f.close()
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# Write a new file prepended with the size and CRC
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else:
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f = open(o_filename, 'wb')
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f.write(flength)
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f.write(fcrc)
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f.write(fdata)
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f.close()
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