def decode(self):
assert self.data is None and self.rawdata is not None
data = self.rawdata
if self.decipher:
# Handle encryption
data = self.decipher(self.objid, self.genno, data, self.attrs)
filters = self.get_filters()
if not filters:
self.data = data
self.rawdata = None
return
for f in filters:
params = self.get_any(('DP', 'DecodeParms', 'FDecodeParms'), {})
if f in LITERALS_FLATE_DECODE:
# will get errors if the document is encrypted.
try:
data = zlib.decompress(data)
except zlib.error as e:
if STRICT:
raise PDFException('Invalid zlib bytes: %r, %r' % (e, data))
data = ''
elif f in LITERALS_LZW_DECODE:
data = lzwdecode(data)
elif f in LITERALS_ASCII85_DECODE:
data = ascii85decode(data)
elif f in LITERALS_ASCIIHEX_DECODE:
data = asciihexdecode(data)
elif f in LITERALS_RUNLENGTH_DECODE:
data = rldecode(data)
elif f in LITERALS_CCITTFAX_DECODE:
data = ccittfaxdecode(data, params)
elif f in LITERALS_DCT_DECODE:
# This is probably a JPG stream - it does not need to be decoded twice.
# Just return the stream to the user.
pass
elif f == LITERAL_CRYPT:
# not yet..
raise PDFNotImplementedError('/Crypt filter is unsupported')
else:
raise PDFNotImplementedError('Unsupported filter: %r' % f)
# apply predictors
if 'Predictor' in params:
pred = int_value(params['Predictor'])
if pred == 1:
# no predictor
pass
elif 10 <= pred:
# PNG predictor
colors = int_value(params.get('Colors', 1))
columns = int_value(params.get('Columns', 1))
bitspercomponent = int_value(params.get('BitsPerComponent', 8))
data = apply_png_predictor(pred, colors, columns, bitspercomponent, data)
else:
raise PDFNotImplementedError('Unsupported predictor: %r' % pred)
self.data = data
self.rawdata = None
return
elif f == LITERAL_CRYPT:
# not yet..
raise PDFNotImplementedError('/Crypt filter is unsupported')
else:
raise PDFNotImplementedError('Unsupported filter: %r' % f)
# apply predictors
if 'Predictor' in params:
pred = int_value(params['Predictor'])
if pred == 1:
# no predictor
pass
elif 10 <= pred:
# PNG predictor
colors = int_value(params.get('Colors', 1))
columns = int_value(params.get('Columns', 1))
bitspercomponent = int_value(params.get('BitsPerComponent', 8))
data = apply_png_predictor(pred, colors, columns, bitspercomponent, data)
else:
raise PDFNotImplementedError('Unsupported predictor: %r' % pred)
self.data = data
self.rawdata = None
return
def get_data(self):
if self.data is None:
self.decode()
return self.data
def get_rawdata(self):
return self.rawdata
