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Refactored QCC segment parsing. #130

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John Evans 2014-04-04 07:11:43 -04:00
commit 3dbaf9f458
1 changed files with 5 additions and 6 deletions
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glymur/codestream.py
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@ -583,22 +583,21 @@ class Codestream(object):
read_buffer = fptr.read(2) read_buffer = fptr.read(2)
length, = struct.unpack('>H', read_buffer) length, = struct.unpack('>H', read_buffer)
read_buffer = fptr.read(length - 2)
if self._csiz > 256: if self._csiz > 256:
read_buffer = fptr.read(3)
fmt = '>HB' fmt = '>HB'
mantissa_exponent_buffer_length = length - 5 mantissa_exponent_offset = 3
else: else:
read_buffer = fptr.read(2)
fmt = '>BB' fmt = '>BB'
mantissa_exponent_buffer_length = length - 4 mantissa_exponent_offset = 2
cqcc, sqcc = struct.unpack(fmt, read_buffer) cqcc, sqcc = struct.unpack_from(fmt, read_buffer)
if cqcc >= self._csiz: if cqcc >= self._csiz:
msg = "Invalid component number ({0}), " msg = "Invalid component number ({0}), "
msg += "number of components is only {1}." msg += "number of components is only {1}."
msg = msg.format(cqcc, self._csiz) msg = msg.format(cqcc, self._csiz)
warnings.warn(msg) warnings.warn(msg)
spqcc = fptr.read(mantissa_exponent_buffer_length) spqcc = read_buffer[mantissa_exponent_offset:]
return QCCsegment(cqcc, sqcc, spqcc, length, offset) return QCCsegment(cqcc, sqcc, spqcc, length, offset)