def testBufferConstructor(self):
byteSize = 2
bitBuffer = BitBuffer(bytes([1, 2]))
self.assertEqual(8 * byteSize, bitBuffer.getBitSize())
emptyBitSize = 0
emptyBitBuffer = BitBuffer(bytes([]))
self.assertEqual(emptyBitSize, emptyBitBuffer.getBitSize())
def testBufferBitSizeConstructor(self):
bitSize = 11
bitBuffer = BitBuffer(bytes([1, 2]), bitSize)
self.assertEqual(bitSize, bitBuffer.getBitSize())
emptyBitSize = 0
emptyBitBuffer = BitBuffer(bytes([]), emptyBitSize)
self.assertEqual(emptyBitSize, emptyBitBuffer.getBitSize())
outOfRangeBitSize = 9
with self.assertRaises(PythonRuntimeException):
BitBuffer([1], outOfRangeBitSize) # throws!
def writeBitBuffer(self, bitBuffer: BitBuffer) -> None:
"""
Writes a bit buffer to the underlying storage. Length of the bit buffer is written as varuint64
at the beginning.
:param bitBuffer: Bit buffer to write.
"""
bitSize = bitBuffer.getBitSize()
self.writeVarSize(bitSize)
writeBuffer = bitBuffer.getBuffer()
numBytesToWrite = bitSize // 8
numRestBits = bitSize - numBytesToWrite * 8
beginBitPosition = self._bitPosition
if (beginBitPosition & 0x07) != 0:
# we are not aligned to byte
for i in range(numBytesToWrite):
self.writeBits(writeBuffer[i], 8)
else:
# we are aligned to byte
self._byteArray += writeBuffer[0:numBytesToWrite]
self._bitPosition += numBytesToWrite * 8
if numRestBits > 0:
self.writeBits(writeBuffer[numBytesToWrite] >> (8 - numRestBits),
numRestBits)
def testFromBitBuffer(self):
bitBuffer = BitBuffer(bytes([0xAE, 0xEA, 0x80]), 17)
reader = BitStreamReader.fromBitBuffer(bitBuffer)
self.assertEqual(bitBuffer.getBitSize(), reader.getBufferBitSize())
self.assertEqual(0xAEE, reader.readBits(12))
self.assertEqual(0x0A, reader.readBits(4))
self.assertEqual(0x01, reader.readBits(1))
with self.assertRaises(PythonRuntimeException):
reader.readBits(1)
def fromBitBuffer(cls: typing.Type['BitStreamReader'], bitBuffer: BitBuffer) -> 'BitStreamReader':
"""
Constructs bit stream reader from bit buffer.
:param bitBuffer: Bit buffer to read as a bit stream.
"""
instance = cls(bitBuffer.getBuffer())
instance._bitSize = bitBuffer.getBitSize()
return instance
def getBitSizeOfBitBuffer(bitBuffer: BitBuffer) -> int:
"""
Gets the bit size of bit buffer which is stored in bit stream.
:param bitBuffer: Bit buffer for calculation.
:returns: Length of bit buffer in bits.
:raises PythonRuntimeException: Throws if given bit buffer is too long.
"""
bitBufferSize = bitBuffer.getBitSize()
# bit buffer consists of varsize for bit size followed by the bits
return getBitSizeOfVarSize(bitBufferSize) + bitBufferSize
def testGetBitSize(self):
bitSize = 11
bitBuffer = BitBuffer(bytes([0xAB, 0x07]), bitSize)
self.assertEqual(bitSize, bitBuffer.getBitSize())
def testFromBitBufferOverflow(self):
bitBuffer = BitBuffer(bytes([0xFF, 0xFF, 0xF0]), 19)
reader = BitStreamReader.fromBitBuffer(bitBuffer)
self.assertEqual(bitBuffer.getBitSize(), reader.getBufferBitSize())
with self.assertRaises(PythonRuntimeException):
reader.readBits(20)