def testAlignTo(self):
writer = BitStreamWriter()
writer.writeBits(5, 3)
writer.alignTo(8)
self.assertEqual(8, writer.getBitPosition())
writer.writeBits(0, 1)
writer.alignTo(16)
self.assertEqual(16, writer.getBitPosition())
writer.writeBits(0xaa, 9)
writer.alignTo(32)
self.assertEqual(32, writer.getBitPosition())
writer.writeBits(0xaca, 13)
writer.alignTo(64)
self.assertEqual(64, writer.getBitPosition())
writer.writeBits(0xcafe, 16)
reader = BitStreamReader(buffer=writer.getByteArray())
self.assertEqual(5, reader.readBits(3))
reader.alignTo(8)
self.assertEqual(8, reader.getBitPosition())
self.assertEqual(0, reader.readBits(1))
reader.alignTo(16)
self.assertEqual(16, reader.getBitPosition())
self.assertEqual(0xaa, reader.readBits(9))
reader.alignTo(32)
self.assertEqual(32, reader.getBitPosition())
self.assertEqual(0xaca, reader.readBits(13))
reader.alignTo(64)
self.assertEqual(64, reader.getBitPosition())
self.assertEqual(0xcafe, reader.readBits(16))
def write(self, writer: BitStreamWriter, value: int) -> None:
"""
Writes unsigned fixed integer Zserio type to the bit stream.
:param writer: Bit stream where to write.
:param value: Unsigned fixed integer Zserio type to write.
"""
writer.writeBits(value, self._numBits)
def testFile(self):
testFilename = "BitStreamTest.bin"
writer = BitStreamWriter()
writer.writeBits(13, 7)
writer.writeString(testFilename)
writer.writeVarInt(-123456)
writer.toFile(testFilename)
reader = BitStreamReader.fromFile(testFilename)
self.assertEqual(13, reader.readBits(7))
self.assertEqual(testFilename, reader.readString())
self.assertEqual(-123456, reader.readVarInt())
def _testImpl(self, writeMethod, readMethod, values, maxStartBitPos):
for bitPos in range(maxStartBitPos):
writer = BitStreamWriter()
if bitPos > 0:
writer.writeBits(0, bitPos)
for value in values:
writeMethod(writer, value)
reader = BitStreamReader(buffer=writer.getByteArray())
if bitPos > 0:
reader.readBits(bitPos)
for value in values:
self.assertEqual(value, readMethod(reader), "[bitPos=%d]" % bitPos)
def _testBitsImpl(self, writeMethod, readMethod, values, numBits):
for bitPos in range(numBits):
writer = BitStreamWriter()
if bitPos > 0:
writer.writeBits(0, bitPos)
for value in values:
writeMethod(writer, value, numBits)
reader = BitStreamReader(buffer=writer.getByteArray())
if bitPos > 0:
reader.readBits(bitPos)
for value in values:
self.assertEqual(value, readMethod(reader, numBits),
"[numBits=%d, bitPos=%d]" % (numBits, bitPos))
def testWriteUnalignedData(self):
# number expected to be written at offset
testValue = 123
for offset in range(65):
writer = BitStreamWriter()
if offset != 0:
writer.writeBits(0, offset)
writer.writeBits(testValue, 8)
# check written value
buffer = writer.getByteArray()
writtenTestValue = buffer[offset // 8] << (offset % 8)
if offset % 8 != 0:
writtenTestValue |= buffer[offset // 8 + 1] >> (8 - (offset % 8))
self.assertEqual(testValue, writtenTestValue, msg=("Offset: " + str(offset)))
def testBitPosition(self):
writer = BitStreamWriter()
writer.writeBits(0xaaaa, 16)
self.assertEqual(16, writer.getBitPosition())
writer.writeBits(0xff, 8)
self.assertEqual(24, writer.getBitPosition())
reader = BitStreamReader(buffer=writer.getByteArray())
self.assertEqual(0xaaaa, reader.readBits(16))
self.assertEqual(16, reader.getBitPosition())
reader.setBitPosition(8)
self.assertEqual(8, reader.getBitPosition())
self.assertEqual(0xaaff, reader.readBits(16))
reader.setBitPosition(13)
self.assertEqual(13, reader.getBitPosition())
self.assertEqual(0x02, reader.readBits(3))
self.assertEqual(16, reader.getBitPosition())
self.assertEqual(0xff, reader.readBits(8))
self.assertEqual(24, reader.getBitPosition())
reader.setBitPosition(0)
self.assertEqual(0, reader.getBitPosition())
self.assertEqual(0xaaaaff, reader.readBits(24))
def testWriteBits(self):
writer = BitStreamWriter()
writer.writeBits(0, 8)
writer.writeBits(255, 8)
writer.writeBits(1, 1)
writer.writeBits(0x3f, 6)
writer.writeBits(1, 1)
self.assertEqual(b'\x00\xff\xff', writer.getByteArray())
self.assertEqual(3 * 8, writer.getBitPosition())
writer.writeBits(0xff, 8)
self.assertEqual(b'\x00\xff\xff\xff', writer.getByteArray())
self.assertEqual(4 * 8, writer.getBitPosition())
writer.writeBits(0, 4)
self.assertEqual(b'\x00\xff\xff\xff\x00', writer.getByteArray())
self.assertEqual(4 * 8 + 4, writer.getBitPosition())
writer.writeBits(0x0f, 4)
self.assertEqual(b'\x00\xff\xff\xff\x0f', writer.getByteArray())
self.assertEqual(5 * 8, writer.getBitPosition())
writer.writeBits(0x80, 8)
self.assertEqual(b'\x00\xff\xff\xff\x0f\x80', writer.getByteArray())
self.assertEqual(6 * 8, writer.getBitPosition())
with self.assertRaises(PythonRuntimeException):
writer.writeBits(1, 0) # zero bits!
with self.assertRaises(PythonRuntimeException):
writer.writeBits(1, -1) # negative number of bits!
with self.assertRaises(PythonRuntimeException):
writer.writeBits(256, 8) # above the upper bound
with self.assertRaises(PythonRuntimeException):
writer.writeBits(-1, 8) # below the lower bound
