def test_acceptance(self):
instance = RingBuffer(5)
self.assertEqual(instance.write([1, 2, 3]), 3)
self.assertEqual(instance.write([4, 5, 6]), 2)
self.assertEqual(instance.read(), 1)
self.assertEqual(instance.read(), 2)
self.assertEqual(instance.read(), 3)
def test_read_works_after_several_writes(self):
instance = RingBuffer(3)
self.assertEqual(instance.write([1, 2]), 2)
self.assertEqual(instance.read(), 1)
self.assertEqual(instance.write([3, 4]), 2)
self.assertEqual(instance.read(), 2)
self.assertEqual(instance.write([5, 6]), 1)
self.assertEqual(instance.read(), 3)
def test_basic_wrap(self):
b = RingBuffer(4)
b.write(b"ab")
self.assertEqual(b.read(), b"ab")
self.assertEqual(b.bytes_used(), 0)
b.write(b"cde")
self.assertEqual(b.read(), b"cd")
self.assertEqual(b.read(), b"e")
self.assertEqual(b.read(), None)
def test_size_wrap_and_full(self):
b = RingBuffer(2)
b.write(b"a")
self.assertEqual(b.read(), b"a")
self.assertEqual(b.read(), None)
b.write(b"bc")
self.assertEqual(b.read(), b"b")
self.assertEqual(b.read(), b"c")
self.assertEqual(b.read(), None)
def test_reading_exact_wrapping_full(self):
b = RingBuffer(4)
b.write(b"ab")
self.assertEqual(b.read(), b"ab")
b.write(b"defg")
self.assertEqual(b.read_exactly(4), b"defg")
def test_reading_exact_wrapping_singles(self):
b = RingBuffer(4)
b.write(b"ab")
self.assertEqual(b.read(), b"ab")
b.write(b"defg")
self.assertEqual(b.read_exactly(1), b"d")
self.assertEqual(b.read_exactly(1), b"e")
self.assertEqual(b.read_exactly(1), b"f")
def test_size_one_buffer(self):
b = RingBuffer(1)
self.assertEqual(b.bytes_total(), 1)
self.assertEqual(b.bytes_free(), 1)
self.assertEqual(b.bytes_used(), 0)
b.write(b"a")
self.assertEqual(b.bytes_total(), 1)
self.assertEqual(b.bytes_free(), 0)
self.assertEqual(b.bytes_used(), 1)
self.assertEqual(b.read(), b"a")
self.assertEqual(b.bytes_total(), 1)
self.assertEqual(b.bytes_free(), 1)
self.assertEqual(b.bytes_used(), 0)
self.assertEqual(b.read(), None)
b.write(b"b")
self.assertEqual(b.read(), b"b")
self.assertEqual(b.read(), None)
def test_read_return_first_element(self):
instance = RingBuffer(5)
instance.write([1, 2, 3, 4, 5])
actual = instance.read()
self.assertEqual(actual, 1)
def test_read_raises_when_called_on_empty_buffer(self):
instance = RingBuffer(5)
with self.assertRaises(IndexError):
instance.read()
sys.exit()
# get the args
in_file = sys.argv[1]
sample_rate = int(sys.argv[2])
out_file = sys.argv[3]
# calculate the delay to apply in samples
delay = int(0.1 * sample_rate)
# set up the ring buffer to implement the delay line
buffer = RingBuffer(delay)
with open(in_file, 'rb') as in_file_stream:
with open(out_file, 'wb') as out_file_stream:
left = in_file_stream.read(2)
right = in_file_stream.read(2)
while left and right:
# allow left channel to pass through unchanged
out_file_stream.write(left)
# but delay the right channel
buffer.write(struct.unpack('h', right)[0])
out_file_stream.write(struct.pack('h', buffer.read()))
# perform the next read
left = in_file_stream.read(2)
right = in_file_stream.read(2)
# ensure that the buffer empties before we're done
for i in range(delay):
out_file_stream.write(struct.pack('h', 0))
out_file_stream.write(struct.pack('h', buffer.read()))
def test_basic(self):
b = RingBuffer(6)
b.write(b"abc")
self.assertEqual(b.read(), b"abc")
self.assertEqual(b.read(), None)
def test_write_empty(self):
b = RingBuffer(6)
b.write(b"")
self.assertEqual(b.bytes_used(), 0)
self.assertEqual(b.read(), None)
def test_read_empty(self):
b = RingBuffer(6)
self.assertEqual(b.read(), None)
def test_random_operations(self):
"""A quicktest-lite test to verify various operations work as intended"""
debug_this = False
for test_num in range(1000):
inputs = itertools.cycle(string.ascii_letters.encode("ascii"))
# params for test
operation_count = random.randrange(1, 20)
# possible operations: None = read input, number = write that many bytes
operations = random.choices([None] + list(range(1, 5)),
k=operation_count)
buffer_size = random.randrange(20)
# do the test
buffer = RingBuffer(buffer_size)
read_from_buffer = bytearray()
backup = bytearray()
read_from_backup = bytearray()
for op_i, op in enumerate(operations):
try:
if debug_this:
print("doing op", op)
if op is None:
# slurp all items from buffer
while True:
last_read = buffer.read()
if debug_this:
print("read from buffer", last_read)
if last_read is None:
break
else:
read_from_buffer.extend(last_read)
# slurp all items from backup
read_from_backup.extend(backup)
backup.clear()
else:
# check we can't write more than we have space for
if len(backup) + op > buffer_size:
with self.assertRaises(ValueError):
items_to_write = list(
itertools.islice(inputs, op))
buffer.write(items_to_write)
# actually try and write no more than we have space for
count_to_write = min(op, buffer_size - len(backup))
items_to_write = bytes(
list(itertools.islice(inputs, count_to_write)))
if debug_this:
print("to_write", items_to_write)
buffer.write(items_to_write)
backup.extend(items_to_write)
if debug_this:
print("buffer:", buffer)
self.assertEqual(read_from_buffer, read_from_backup)
except AssertionError as e:
message = e.args[0]
message += "\nFailed on test number {}".format(test_num)
message += "\nOperation: #{op_i} ('{op}')".format(
op_i=op_i, op=op)
message += "\nParams:\n\toperations={operations}\n\tbuffer_size={buffer_size}".format(
operations=operations, buffer_size=buffer_size)
message += "\nState:\n\tbuffer={buffer}\n\tbackup={backup}".format(
buffer=buffer, backup=backup)
e.args = (message, )
raise
class Messenger(object):
def __init__(self, socket):
self.socket = socket
self._read_buffer = RingBuffer(2**20)
self._send_buffer = RingBuffer(2**20)
self._parser = MessageReader()
def debug(self, s):
print("Messenger{}: {}".format(self.socket.getpeername(), s))
def read_messages(self):
"""Call this you when know there is readable data for this socket;
it will yield a tuple in the format of (transaction_id, message object)
for each message that has been received."""
bytes_read = self.socket.recv(2048)
if len(bytes_read) == 0:
raise MessengerConnectionBroken("Socket connection broken",
self.socket)
self.debug("read {} bytes".format(len(bytes_read)))
try:
self._read_buffer.write(bytes_read)
except ValueError:
raise MessengerBufferFullError(
"Failed to read message because read buffer is full",
self.socket)
while True:
parsed = self._parser.try_parse(self._read_buffer)
if parsed is None:
return
else:
(tid, message) = parsed
self.debug("received message; tid: {} message: {}".format(
tid, message))
yield tid, message
def queue_message(self, tid, message):
"""An API for queuing messages for sending later"""
self.debug("queuing message; tid: {} message: {}".format(
tid, message))
data = bson.dumps(message)
header = struct.pack(MSG_HEADER_FMT, tid, len(data))
try:
self._send_buffer.write(header)
self._send_buffer.write(data)
except ValueError:
MessengerBufferFullError(
"Failed to enqueue message because send buffer is full",
self.socket)
def has_messages_to_send(self):
"""Returns true if a message was previously queued but has not yet been sent"""
return self._send_buffer.bytes_used() > 0
def send_messages(self):
"""Call this to actually send messages previous queued"""
while True:
to_send = self._send_buffer.read()
if to_send is None:
break
self.debug("sending {} bytes".format(len(to_send)))
message_length = len(to_send)
bytes_sent_total = 0
while bytes_sent_total < message_length:
sent = self.socket.send(to_send[bytes_sent_total:])
if sent == 0:
raise MessengerConnectionBroken(
"error sending, probably socket connection broke",
self.socket)
bytes_sent_total += sent