def deserialise(self, packetPayloadString):
'''Deserialises a packet payload ASCII string into list of transaction elements'''
# 1) Unpack the string into unsigned integers
try:
rawU32Array = array('I', packetPayloadString) # Unpack string to an unsigned 32-bit array
except Exception as err:
raise ChipsException("Deserialisation error:\n\t" + str(err))
# 2) Debug output of the raw packet
if chipsLog.level <= logging.DEBUG:
msg = "\nRaw received packet content is:\n"
for u32 in rawU32Array: msg += " 0x" + uInt32HexStr(u32) + "\n"
chipsLog.debug(msg)
# 3) Detect if we need to do a byte-reorder
firstWord = rawU32Array[0]
firstWordMasked = firstWord & 0xf00000f0 # This selects only the bits relevant for detecting the byte ordering
if firstWordMasked == 0x200000f0:
chipsLog.debug("Packet header detected: no byte-reorder is required.")
elif firstWordMasked == 0xf0000020:
chipsLog.debug("Packet header detected: a byte-reorder will be performed.")
self._doByteReorder = True
else:
chipsLog.warn("Warning: No packet header (or unknown protocol version)! First word = 0x" + uInt32HexStr(firstWord) + ". Will hope for the best!...")
# 4) Do the byte-reorder if necessary
if self._doByteReorder: rawU32Array.byteswap()
# 5) Now deserialise into a list of TransactionElements
transactionElementList = [] # The list all the deserialised transaction elements will go into
appendToTransactionElementList = transactionElementList.append # This is needed for a speed optimisation
iU32 = 1 # Index for moving through the rawU32Array # TEMPORARY IPBUS V2.x HACK! Skip the first word which is now a packet ID
rawU32ArraySize = len(rawU32Array)
while iU32 < rawU32ArraySize:
expectedBodySize = getExpectedBodySize(rawU32Array[iU32])
if rawU32ArraySize - iU32 - 1 - expectedBodySize < 0:
raise ChipsException("Deserialisation error: packet not correctly formatted " \
"or does not contain the expected amount of data!")
appendToTransactionElementList(TransactionElement(rawU32Array[iU32: iU32 + 1 + expectedBodySize]))
iU32 += (1 + expectedBodySize)
# 6) Debug output of deserialised packet content
if chipsLog.level <= logging.DEBUG:
msg = "\nDeserialised packet content is:\n" \
+ reprTransactionElementList(transactionElementList)
chipsLog.debug(msg)
return transactionElementList
class SerDes(object):
'''Class for serialising/deserialising IPbus transaction data
Can serialise a list of TransactionElements into a string, or deserialise
a string into a list of TransactionElements. The deserialisation stage
checks the byte-ordering by looking for a byte-order header, and deals
with the byte-reordering as appropriate. If a byte-reorder was required
on the deserialisation stage, then the serialisation stage will also
perform a reorder in order to respond correctly.
Byte-reordering is off by default, as it's obviously a waste of CPU.
'''
def __init__(self):
'''Constructor - no arguments'''
object.__init__(self)
self._doByteReorder = False
def serialise(self, transactionElementList):
'''Serialises a list of transaction elements into an ASCII string for transmission'''
if chipsLog.level <= logging.DEBUG:
msg = "\nSerialising the following packet content:\n"
msg += reprTransactionElementList(transactionElementList)
chipsLog.debug(msg)
allTransactionsArray = array(
'I', [0x200000f0]
) # TEMPORARY IPBUS V2.x HACK! Add a packet header of [0x200000f0] to the beginning of each packet.
extendFunc = allTransactionsArray.extend
for element in transactionElementList:
extendFunc(element.getAll())
if self._doByteReorder: allTransactionsArray.byteswap()
return allTransactionsArray.tostring()
def deserialise(self, packetPayloadString):
'''Deserialises a packet payload ASCII string into list of transaction elements'''
# 1) Unpack the string into unsigned integers
try:
rawU32Array = array('I', packetPayloadString
) # Unpack string to an unsigned 32-bit array
except Exception, err:
raise ChipsException("Deserialisation error:\n\t" + str(err))
# 2) Debug output of the raw packet
if chipsLog.level <= logging.DEBUG:
msg = "\nRaw received packet content is:\n"
for u32 in rawU32Array:
msg += " 0x" + uInt32HexStr(u32) + "\n"
chipsLog.debug(msg)
# 3) Detect if we need to do a byte-reorder
firstWord = rawU32Array[0]
firstWordMasked = firstWord & 0xf00000f0 # This selects only the bits relevant for detecting the byte ordering
if firstWordMasked == 0x200000f0:
chipsLog.debug(
"Packet header detected: no byte-reorder is required.")
elif firstWordMasked == 0xf0000020:
chipsLog.debug(
"Packet header detected: a byte-reorder will be performed.")
self._doByteReorder = True
else:
chipsLog.warn(
"Warning: No packet header (or unknown protocol version)! First word = 0x"
+ uInt32HexStr(firstWord) + ". Will hope for the best!...")
# 4) Do the byte-reorder if necessary
if self._doByteReorder: rawU32Array.byteswap()
# 5) Now deserialise into a list of TransactionElements
transactionElementList = [
] # The list all the deserialised transaction elements will go into
appendToTransactionElementList = transactionElementList.append # This is needed for a speed optimisation
iU32 = 1 # Index for moving through the rawU32Array # TEMPORARY IPBUS V2.x HACK! Skip the first word which is now a packet ID
rawU32ArraySize = len(rawU32Array)
while iU32 < rawU32ArraySize:
expectedBodySize = getExpectedBodySize(rawU32Array[iU32])
if rawU32ArraySize - iU32 - 1 - expectedBodySize < 0:
raise ChipsException("Deserialisation error: packet not correctly formatted " \
"or does not contain the expected amount of data!")
appendToTransactionElementList(
TransactionElement(rawU32Array[iU32:iU32 + 1 +
expectedBodySize]))
iU32 += (1 + expectedBodySize)
# 6) Debug output of deserialised packet content
if chipsLog.level <= logging.DEBUG:
msg = "\nDeserialised packet content is:\n" \
+ reprTransactionElementList(transactionElementList)
chipsLog.debug(msg)
return transactionElementList
