def getExtraField(self):
if self.getExtraFieldLDLength() == 0:
return None
#Handler for case where offset cannot be found in central Directory
if self.zip64Flag["offsetZip64"]:
#If Offset flag present use central directory to find offset in extrafield
startPosition = (46 + self.getFileNameLength())
extraField = self.centralDirectory[startPosition:(
startPosition + self.getExtraFieldCDLength())]
efParser = extra_field_parse.HeaderIdMapping()
efMappings = efParser.HeaderIds()
start = extraField.find("\x01\x00")
blockMagic = extraField[start:start + 2]
blockSize = struct.unpack("<H", extraField[start + 2:start + 4])[0]
parser = efMappings[blockMagic]["parseField"]()
zip64 = parser.parse(efBlock, self.zip64Flag)
offset = zip64["RelativeOffset"]
startPosition = (offset + 30 + self.getFileNameLength())
extraField = self.localDirectory[startPosition:(
startPosition + self.getExtraFieldLDLength())]
else:
startPosition = (self.getRelativeOffset() + 30 +
self.getFileNameLength())
extraField = self.localDirectory[startPosition:(
startPosition + self.getExtraFieldLDLength())]
return self.parseExtraField(extraField)
def parseExtraField(self, extraField):
parsedExtraField = []
efParser = extra_field_parse.HeaderIdMapping()
efMappings = efParser.HeaderIds()
while extraField:
blockMagic = extraField[0:2]
blockSize = struct.unpack("<H", extraField[2:4])[0]
efBlock = extraField[:4 + blockSize]
if blockMagic in efMappings.keys():
#Mapping Header Is known (may or may not have been parsed)
parser = efMappings[blockMagic]["parseField"]()
parsedExtraField.append(parser.parse(efBlock, self.zip64Flag))
else:
#No Header Hits
parser = efMappings["Unknown"]["parseField"]()
parsedExtraField.append(parser.parse(efBlock, self.zip64Flag))
extraField = extraField[4 + blockSize:]
return parsedExtraField