class ElementReader(object):
"""
Create an ElementReader with the elementListener and an initial buffer for
saving partial data.
"""
def __init__(self, elementListener):
self._elementListener = elementListener
self._tlvStructureDecoder = TlvStructureDecoder()
self._usePartialData = False
self._partialData = DynamicByteArray(1000)
self._partialDataLength = 0
def onReceivedData(self, data):
"""
Continue to read data until the end of an element, then call
elementListener.onReceivedElement(element). The buffer passed to
onReceivedElement is only valid during this call. If you need the data
later, you must copy.
:param data: The buffer with the incoming element's bytes.
:type data: An array type with int elements
"""
# Create a Blob and take its buf() since this creates a memoryview
# which is more efficient for slicing.
data = Blob(data, False).buf()
# Process multiple objects in the data.
while True:
try:
if not self._usePartialData:
# This is the beginning of an element.
if len(data) <= 0:
# Wait for more data.
return
# Scan the input to check if a whole TLV element has been read.
self._tlvStructureDecoder.seek(0)
gotElementEnd = self._tlvStructureDecoder.findElementEnd(data)
offset = self._tlvStructureDecoder.getOffset()
except ValueError as ex:
# Reset to read a new element on the next call.
self._usePartialData = False
self._tlvStructureDecoder = TlvStructureDecoder()
raise ex
if gotElementEnd:
# Got the remainder of an element. Report to the caller.
if self._usePartialData:
# We have partial data from a previous call, so append this
# data and use partialData for onReceivedElement.
self._partialData.copy(
data[:offset], self._partialDataLength)
self._partialDataLength += offset
# Create a Blob and take its buf() since this creates a
# memoryview which is more efficient for slicing.
partialDataView = Blob(
self._partialData.getArray(), False).buf()
element = partialDataView[:self._partialDataLength]
# Assume we don't need to use partialData anymore until
# needed.
self._usePartialData = False
else:
# We are not using partialData, so just point to the input
# data buffer.
element = data[:offset]
# Reset to read a new object. Do this before calling
# onReceivedElement in case it throws an exception.
data = data[offset:]
self._tlvStructureDecoder = TlvStructureDecoder()
self._elementListener.onReceivedElement(element)
if len(data) == 0:
# No more data in the packet.
return
# else loop back to decode.
else:
# Save remaining data for a later call.
if not self._usePartialData:
self._usePartialData = True
self._partialDataLength = 0
if self._partialDataLength + len(data) > Common.MAX_NDN_PACKET_SIZE:
# Reset to read a new element on the next call.
self._usePartialData = False
self._tlvStructureDecoder = TlvStructureDecoder()
raise ValueError(
"The incoming packet exceeds the maximum limit Face.getMaxNdnPacketSize()")
self._partialData.copy(data, self._partialDataLength)
self._partialDataLength += len(data)
return
class ElementReader(object):
"""
Create an ElementReader with the elementListener and an initial buffer for
saving partial data.
"""
def __init__(self, elementListener):
self._elementListener = elementListener
self._tlvStructureDecoder = TlvStructureDecoder()
self._usePartialData = False
self._partialData = DynamicByteArray(1000)
self._partialDataLength = 0
def onReceivedData(self, data):
"""
Continue to read data until the end of an element, then call
elementListener.onReceivedElement(element). The buffer passed to
onReceivedElement is only valid during this call. If you need the data
later, you must copy.
:param data: The buffer with the incoming element's bytes.
:type data: An array type with int elements
"""
# Create a Blob and take its buf() since this creates a memoryview
# which is more efficient for slicing.
data = Blob(data, False).buf()
# Process multiple objects in the data.
while True:
try:
if not self._usePartialData:
# This is the beginning of an element.
if len(data) <= 0:
# Wait for more data.
return
# Scan the input to check if a whole TLV element has been read.
self._tlvStructureDecoder.seek(0)
gotElementEnd = self._tlvStructureDecoder.findElementEnd(data)
offset = self._tlvStructureDecoder.getOffset()
except ValueError as ex:
# Reset to read a new element on the next call.
self._usePartialData = False
self._tlvStructureDecoder = TlvStructureDecoder()
raise ex
if gotElementEnd:
# Got the remainder of an element. Report to the caller.
if self._usePartialData:
# We have partial data from a previous call, so append this
# data and use partialData for onReceivedElement.
self._partialData.copy(
data[:offset], self._partialDataLength)
self._partialDataLength += offset
# Create a Blob and take its buf() since this creates a
# memoryview which is more efficient for slicing.
partialDataView = Blob(
self._partialData.getArray(), False).buf()
element = partialDataView[:self._partialDataLength]
# Assume we don't need to use partialData anymore until
# needed.
self._usePartialData = False
else:
# We are not using partialData, so just point to the input
# data buffer.
element = data[:offset]
# Reset to read a new object. Do this before calling
# onReceivedElement in case it throws an exception.
data = data[offset:]
self._tlvStructureDecoder = TlvStructureDecoder()
self._elementListener.onReceivedElement(element)
if len(data) == 0:
# No more data in the packet.
return
# else loop back to decode.
else:
# Save remaining data for a later call.
if not self._usePartialData:
self._usePartialData = True
self._partialDataLength = 0
if self._partialDataLength + len(data) > Common.MAX_NDN_PACKET_SIZE:
# Reset to read a new element on the next call.
self._usePartialData = False
self._tlvStructureDecoder = TlvStructureDecoder()
raise ValueError(
"The incoming packet exceeds the maximum limit Face.getMaxNdnPacketSize()")
self._partialData.copy(data, self._partialDataLength)
self._partialDataLength += len(data)
return
class ElementReader(object):
"""
Create an ElementReader with the elementListener and an initial buffer for
saving partial data.
"""
def __init__(self, elementListener):
self._elementListener = elementListener
self._binaryXmlStructureDecoder = BinaryXmlStructureDecoder()
self._tlvStructureDecoder = TlvStructureDecoder()
self._usePartialData = False
self._partialData = DynamicByteArray(1000)
self._useTlv = None
def onReceivedData(self, data):
"""
Continue to read data until the end of an element, then call
elementListener.onReceivedElement(element). The buffer passed to
onReceivedElement is only valid during this call. If you need the data
later, you must copy.
:param data: The buffer with the incoming element's bytes.
:type data: An array type with int elements
"""
# Create a Blob and take its buf() since this creates a memoryview
# which is more efficient for slicing.
data = Blob(data, False).buf()
# Process multiple objects in the data.
while True:
if not self._usePartialData:
# This is the beginning of an element. Check whether it is
# Binary XML or TLV.
if len(data) <= 0:
# Wait for more data.
return
# The type codes for TLV Interest and Data packets are chosen to not
# conflict with the first byte of a binary XML packet, so we can
# just look at the first byte.
if (data[0] == Tlv.Interest or data[0] == Tlv.Data or
data[0] == 0x80):
self._useTlv = True
else:
# Binary XML.
self._useTlv = False
if self._useTlv:
# Scan the input to check if a whole TLV element has been read.
self._tlvStructureDecoder.seek(0)
gotElementEnd = self._tlvStructureDecoder.findElementEnd(data)
offset = self._tlvStructureDecoder.getOffset()
else:
# Scan the input to check if a whole Binary XML element has been
# read.
self._binaryXmlStructureDecoder.seek(0)
gotElementEnd = self._binaryXmlStructureDecoder.findElementEnd(data)
offset = self._binaryXmlStructureDecoder.getOffset()
if gotElementEnd:
# Got the remainder of an element. Report to the caller.
if self._usePartialData:
# We have partial data from a previous call, so append this
# data and use partialData for onReceivedElement.
self._partialData.copy(
data[:offset], self._partialDataLength)
self._partialDataLength += offset
# Create a Blob and take its buf() since this creates a
# memoryview which is more efficient for slicing.
partialDataView = Blob(
self._partialData.getArray(), False).buf()
self._elementListener.onReceivedElement(
partialDataView[:self._partialDataLength])
# Assume we don't need to use partialData anymore until
# needed.
self._usePartialData = False
else:
# We are not using partialData, so just point to the input
# data buffer.
self._elementListener.onReceivedElement(data[:offset])
# Need to read a new object.
data = data[offset:]
self._binaryXmlStructureDecoder = BinaryXmlStructureDecoder()
self._tlvStructureDecoder = TlvStructureDecoder()
if len(data) == 0:
# No more data in the packet.
return
# else loop back to decode.
else:
# Save remaining data for a later call.
if not self._usePartialData:
self._usePartialData = True
self._partialDataLength = 0
self._partialData.copy(data, self._partialDataLength)
self._partialDataLength += len(data)
return
class BinaryXmlStructureDecoder(object):
"""
Create and initialize a BinaryXmlStructureDecoder.
"""
def __init__(self):
self._gotElementEnd = False
self._offset = 0
self._level = 0
self._state = self.READ_HEADER_OR_CLOSE
self._headerLength = 0
self._useHeaderBuffer = False
# 10 bytes is enough to hold an encoded header with a type and a 64 bit value.
self._headerBuffer = DynamicByteArray(10)
self._nBytesToRead = 0
READ_HEADER_OR_CLOSE = 0
READ_BYTES = 1
def findElementEnd(self, input):
"""
Continue scanning input starting from self._offset to find the element
end. If the end of the element which started at offset 0 is found,
this returns True and getOffset() is the length of the element.
Otherwise, this returns False which means you should read more into
input and call again.
:param input: The input buffer. You have to pass in input each time
because the buffer could be reallocated.
:type input: An array type with int elements
:return: True if found the element end, False if not.
:rtype: bool
"""
if self._gotElementEnd:
# Someone is calling when we already got the end.
return True
decoder = BinaryXmlDecoder(input)
while True:
if self._offset >= len(input):
# All the cases assume we have some input.
return False
if self._state == BinaryXmlStructureDecoder.READ_HEADER_OR_CLOSE:
# First check for CLOSE.
if (self._headerLength == 0 and
input[self._offset] == BinaryXmlDecoder.CLOSE):
self._offset += 1
# Close the level.
self._level -= 1
if self._level == 0:
# Finished.
self._gotElementEnd = True
return True
if self._level < 0:
raise RuntimeError(
"BinaryXmlStructureDecoder: Unexpected close tag at offset " +
repr(self._offset - 1))
# Get ready for the next header.
self._startHeader()
continue
startingHeaderLength = self._headerLength
while True:
if self._offset >= len(input):
# We can't get all of the header bytes from this input.
# Save in headerBuffer.
self._useHeaderBuffer = True
nNewBytes = self._headerLength - startingHeaderLength
self._headerBuffer.copy(
input[self._offset - nNewBytes:self._offset],
startingHeaderLength)
return False
headerByte = input[self._offset]
self._offset += 1
self._headerLength += 1
if headerByte & BinaryXmlDecoder.TT_FINAL:
# Break and read the header.
break
if self._useHeaderBuffer:
# Copy the remaining bytes into headerBuffer.
nNewBytes = self._headerLength - startingHeaderLength
self._headerBuffer.copy(
input[self._offset - nNewBytes:self._offset],
startingHeaderLength)
(type, value) = BinaryXmlDecoder(
self._headerBuffer.getArray()).decodeTypeAndValue()
else:
# We didn't have to use the headerBuffer.
decoder.seek(self._offset - self._headerLength)
(type, value) = decoder.decodeTypeAndValue()
# Set the next state based on the type.
if type == BinaryXmlDecoder.DATTR:
# We already consumed the item. READ_HEADER_OR_CLOSE again.
# ndnb has rules about what must follow an attribute, but we
# are just scanning.
self._startHeader()
elif (type == BinaryXmlDecoder.DTAG or
type == BinaryXmlDecoder.EXT):
# Start a new level and READ_HEADER_OR_CLOSE again.
self._level += 1
self._startHeader()
elif (type == BinaryXmlDecoder.TAG or
type == BinaryXmlDecoder.ATTR):
if type == BinaryXmlDecoder.TAG:
# Start a new level and read the tag.
self._level += 1
# Minimum tag or attribute length is 1.
self._nBytesToRead = value + 1
self._state = BinaryXmlStructureDecoder.READ_BYTES
# ndnb has rules about what must follow an attribute, but we
# are just scanning.
elif (type == BinaryXmlDecoder.BLOB or
type == BinaryXmlDecoder.UDATA):
self._nBytesToRead = value
self._state = BinaryXmlStructureDecoder.READ_BYTES
else:
raise RuntimeError(
"BinaryXmlStructureDecoder: Unrecognized header type " +
repr(type))
elif self._state == BinaryXmlStructureDecoder.READ_BYTES:
nRemainingBytes = len(input) - self._offset
if nRemainingBytes < self._nBytesToRead:
# Need more.
self._offset += nRemainingBytes
self._nBytesToRead -= nRemainingBytes
return False
# Got the bytes. Read a new header or close.
self._offset += self._nBytesToRead
self._startHeader()
else:
# We don't expect this to happen.
raise RuntimeError(
"BinaryXmlStructureDecoder: Unrecognized state " +
repr(self._state))
def getOffset(self):
"""
Get the current offset into the input buffer.
:return: The offset.
:rtype: int
"""
return self._offset
def seek(self, offset):
"""
Set the offset into the input, used for the next read.
:param int offset: The new offset.
"""
self._offset = offset
def _startHeader(self):
"""
A private method to set the state to READ_HEADER_OR_CLOSE and set up to
start reading the header.
"""
self._headerLength = 0
self._useHeaderBuffer = False
self._state = BinaryXmlStructureDecoder.READ_HEADER_OR_CLOSE
class ElementReader(object):
"""
Create an ElementReader with the elementListener and an initial buffer for
saving partial data.
"""
def __init__(self, elementListener):
self._elementListener = elementListener
self._binaryXmlStructureDecoder = BinaryXmlStructureDecoder()
self._tlvStructureDecoder = TlvStructureDecoder()
self._usePartialData = False
self._partialData = DynamicByteArray(1000)
self._useTlv = None
def onReceivedData(self, data):
"""
Continue to read data until the end of an element, then call
elementListener.onReceivedElement(element). The buffer passed to
onReceivedElement is only valid during this call. If you need the data
later, you must copy.
:param data: The buffer with the incoming element's bytes.
:type data: An array type with int elements
"""
# Create a Blob and take its buf() since this creates a memoryview
# which is more efficient for slicing.
data = Blob(data, False).buf()
# Process multiple objects in the data.
while True:
if not self._usePartialData:
# This is the beginning of an element. Check whether it is
# Binary XML or TLV.
if len(data) <= 0:
# Wait for more data.
return
# The type codes for TLV Interest and Data packets are chosen to not
# conflict with the first byte of a binary XML packet, so we can
# just look at the first byte.
if (data[0] == Tlv.Interest or data[0] == Tlv.Data
or data[0] == 0x80):
self._useTlv = True
else:
# Binary XML.
self._useTlv = False
if self._useTlv:
# Scan the input to check if a whole TLV element has been read.
self._tlvStructureDecoder.seek(0)
gotElementEnd = self._tlvStructureDecoder.findElementEnd(data)
offset = self._tlvStructureDecoder.getOffset()
else:
# Scan the input to check if a whole Binary XML element has been
# read.
self._binaryXmlStructureDecoder.seek(0)
gotElementEnd = self._binaryXmlStructureDecoder.findElementEnd(
data)
offset = self._binaryXmlStructureDecoder.getOffset()
if gotElementEnd:
# Got the remainder of an element. Report to the caller.
if self._usePartialData:
# We have partial data from a previous call, so append this
# data and use partialData for onReceivedElement.
self._partialData.copy(data[:offset],
self._partialDataLength)
self._partialDataLength += offset
# Create a Blob and take its buf() since this creates a
# memoryview which is more efficient for slicing.
partialDataView = Blob(self._partialData.getArray(),
False).buf()
self._elementListener.onReceivedElement(
partialDataView[:self._partialDataLength])
# Assume we don't need to use partialData anymore until
# needed.
self._usePartialData = False
else:
# We are not using partialData, so just point to the input
# data buffer.
self._elementListener.onReceivedElement(data[:offset])
# Need to read a new object.
data = data[offset:]
self._binaryXmlStructureDecoder = BinaryXmlStructureDecoder()
self._tlvStructureDecoder = TlvStructureDecoder()
if len(data) == 0:
# No more data in the packet.
return
# else loop back to decode.
else:
# Save remaining data for a later call.
if not self._usePartialData:
self._usePartialData = True
self._partialDataLength = 0
self._partialData.copy(data, self._partialDataLength)
self._partialDataLength += len(data)
return