51 lines
1.1 KiB
Plaintext
51 lines
1.1 KiB
Plaintext
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def encode(data):
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if not data:
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return
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l = len(data)
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if l % 2 != 0:
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return None
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ret = bytearray()
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for i in range(0, l, 2):
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usTmp = data[i] << 8
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usTmp += data[i + 1]
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ucByte = ((usTmp >> 12) & 0xff)
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if i >= l - 2:
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ucByte |= ((1 << 5) & 0xff)
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if i < 2:
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ucByte |= ((1 << 6) & 0xff)
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a = ((2 << 6) & 0xff)
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a += ((usTmp >> 6) & 0x3f)
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b = ((3 << 6) & 0xff)
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b += (usTmp & 0x3f)
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ret.append(ucByte)
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ret.append(a)
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ret.append(b)
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return ret
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def decode(data):
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if not data:
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return
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l = len(data)
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if l % 3 != 0:
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return None
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ret = bytearray()
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for i in range(0, l, 3):
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val = data[i]
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usTmp = (val & 0x0f)
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usTmp <<= 6
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val = data[i + 1]
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a = (val & 0x3f)
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usTmp += a
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usTmp <<= 6
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val = data[i + 2]
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b = (val & 0x3f)
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usTmp += b
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a = (usTmp >> 8) & 0xff
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b = (usTmp & 0xff)
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ret.append(a)
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ret.append(b)
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return ret
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