class Tiff(object):
BYTEORDER={
'<': 'little-endian',
'>': 'big-endian'
}
def __init__(self, fp):
self.fp=fp
self.byteorder=None
self.magic=None
self.offset=None
self.br=None
self.directory=TiffRootDirectory()
self.readHeader() # sets self.offset
self.readIFDs(self.offset)
def readHeader(self):
last=None
for byte in self.fp.read(2):
if last != None and byte != last:
raise TiffException('Inconsistent TIFF byte order mark')
if ord(byte)==0b1001101: # MM, motorola, or big-endian
bo='>'
elif ord(byte)==0b1001001: # II, intel, or little-endian
bo='<'
else:
raise TiffException('Unknown byte order in file')
self.byteorder=self.BYTEORDER[bo]
last=byte
self.br=BinaryReader(self.fp, bo)
self.magic=self.br.read()
if int(self.magic) != 42:
raise TiffException('Invalid magic number')
self.offset=self.br.read(4, 'I')
def readIFDs(self, start):
done=False
while not done:
td=TiffDirectory(self.br, start)
self.directory.append(td)
if not td.next:
done=True
start=td.next
def __init__(self, fp): self.fp=fp self.byteorder=None self.magic=None self.offset=None self.br=None self.directory=TiffRootDirectory() self.readHeader() # sets self.offset self.readIFDs(self.offset)
