All the known marker segments parsers are now methods. #94
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John Evans
parent
e53a9a9157
commit
40e91dae7f
1 changed files with 202 additions and 203 deletions
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@ -165,7 +165,7 @@ class Codestream(object):
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segment = self._parse_plt_segment(fptr)
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elif marker_id == 0xff5c:
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segment = _parse_qcd_segment(fptr)
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segment = self._parse_qcd_segment(fptr)
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elif marker_id == 0xff5d:
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segment = self._parse_qcc_segment(fptr)
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@ -177,38 +177,25 @@ class Codestream(object):
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segment = self._parse_pod_segment(fptr)
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elif marker_id == 0xff60:
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segment = _parse_ppm_segment(fptr)
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segment = self._parse_ppm_segment(fptr)
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elif marker_id == 0xff61:
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segment = _parse_ppt_segment(fptr)
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segment = self._parse_ppt_segment(fptr)
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elif marker_id == 0xff63:
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segment = _parse_crg_segment(fptr, self._csiz)
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segment = self._parse_crg_segment(fptr)
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elif marker_id == 0xff64:
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segment = _parse_cme_segment(fptr)
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segment = self._parse_cme_segment(fptr)
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elif marker_id == 0xff90:
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# Need to keep easy access to tile offsets and lengths for when
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# we encounter start-of-data marker segments.
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segment = _parse_sot_segment(fptr)
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self._tile_offset.append(segment.offset)
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if segment.psot == 0:
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tile_part_length = (self.offset + self.length -
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segment.offset - 2)
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else:
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tile_part_length = segment.psot
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self._tile_length.append(tile_part_length)
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segment = self._parse_sot_segment(fptr)
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elif marker_id == 0xff93:
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# start of data. Need to seek past the current tile part.
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# The last SOT marker segment has the info that we need.
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segment = _parse_sod_segment(fptr)
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segment = self._parse_sod_segment(fptr)
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elif marker_id == 0xffd9:
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# end of codestream
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segment = _parse_eoc_segment(fptr)
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segment = self._parse_eoc_segment(fptr)
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elif marker_id in _VALID_MARKERS:
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# It's a reserved marker that I don't know anything about.
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@ -277,6 +264,29 @@ class Codestream(object):
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msg += ''.join(strs)
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return msg
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def _parse_cme_segment(self, fptr):
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"""Parse the CME marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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CME segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(4)
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data = struct.unpack('>HH', read_buffer)
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length = data[0]
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rcme = data[1]
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ccme = fptr.read(length - 4)
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return CMEsegment(rcme, ccme, length, offset)
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def _parse_coc_segment(self, fptr):
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"""Parse the COC marker segment.
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@ -350,6 +360,49 @@ class Codestream(object):
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return CODsegment(scod, spcod, length, offset)
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def _parse_crg_segment(self, fptr):
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"""Parse the CRG marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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CRG segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(2)
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length, = struct.unpack('>H', read_buffer)
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read_buffer = fptr.read(4 * self._csiz)
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data = struct.unpack('>' + 'HH' * self._csiz, read_buffer)
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xcrg = data[0::2]
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ycrg = data[1::2]
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return CRGsegment(xcrg, ycrg, length, offset)
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def _parse_eoc_segment(self, fptr):
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"""Parse the EOC (end-of-codestream) marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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EOC Segment instance.
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"""
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offset = fptr.tell() - 2
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length = 0
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return EOCsegment(length, offset)
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def _parse_plt_segment(self, fptr):
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"""Parse the PLT segment.
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@ -420,6 +473,57 @@ class Codestream(object):
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return PODsegment(pod_params, length, offset)
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def _parse_ppm_segment(self, fptr):
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"""Parse the PPM segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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PPM segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, zppm = struct.unpack('>HB', read_buffer)
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numbytes = length - 3
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read_buffer = fptr.read(numbytes)
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return PPMsegment(zppm, read_buffer, length, offset)
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def _parse_ppt_segment(self, fptr):
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"""Parse the PPT segment.
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The packet headers are not parsed, i.e. they remain "uninterpreted"
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raw data beffers.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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PPT segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, zppt = struct.unpack('>HB', read_buffer)
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length = length
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zppt = zppt
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numbytes = length - 3
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ippt = fptr.read(numbytes)
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return PPTsegment(zppt, ippt, length, offset)
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def _parse_qcc_segment(self, fptr):
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"""Parse the QCC segment.
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@ -456,6 +560,26 @@ class Codestream(object):
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return QCCsegment(cqcc, sqcc, spqcc, length, offset)
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def _parse_qcd_segment(self, fptr):
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"""Parse the QCD segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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QCD Segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, sqcd = struct.unpack('>HB', read_buffer)
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spqcd = fptr.read(length - 3)
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return QCDsegment(sqcd, spqcd, length, offset)
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def _parse_rgn_segment(self, fptr):
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"""Parse the RGN segment.
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@ -519,6 +643,63 @@ class Codestream(object):
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return segment
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def _parse_sod_segment(self, fptr):
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"""Parse the SOD (start-of-data) segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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SOD segment instance.
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"""
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offset = fptr.tell() - 2
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length = 0
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return SODsegment(length, offset)
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def _parse_sot_segment(self, fptr):
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"""Parse the SOT segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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SOT segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(10)
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data = struct.unpack('>HHIBB', read_buffer)
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length = data[0]
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isot = data[1]
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psot = data[2]
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tpsot = data[3]
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tnsot = data[4]
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segment = SOTsegment(isot, psot, tpsot, tnsot, length, offset)
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# Need to keep easy access to tile offsets and lengths for when
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# we encounter start-of-data marker segments.
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self._tile_offset.append(segment.offset)
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if segment.psot == 0:
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tile_part_length = (self.offset + self.length -
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segment.offset - 2)
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else:
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tile_part_length = segment.psot
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self._tile_length.append(tile_part_length)
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return segment
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def _parse_tlm_segment(self, fptr):
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"""Parse the TLM segment.
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@ -1584,188 +1765,6 @@ def _print_quantization_style(sqcc):
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return msg
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def _parse_sot_segment(fptr):
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"""Parse the SOT segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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SOT segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(10)
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data = struct.unpack('>HHIBB', read_buffer)
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length = data[0]
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isot = data[1]
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psot = data[2]
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tpsot = data[3]
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tnsot = data[4]
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return SOTsegment(isot, psot, tpsot, tnsot, length, offset)
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def _parse_sod_segment(fptr):
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"""Parse the SOD segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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SOD segment instance.
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"""
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offset = fptr.tell() - 2
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length = 0
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return SODsegment(length, offset)
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def _parse_qcd_segment(fptr):
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"""Parse the QCD segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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QCD Segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, sqcd = struct.unpack('>HB', read_buffer)
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spqcd = fptr.read(length - 3)
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return QCDsegment(sqcd, spqcd, length, offset)
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def _parse_ppt_segment(fptr):
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"""Parse the PPT segment.
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The packet headers are not parsed, i.e. they remain "uninterpreted"
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raw data beffers.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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PPT segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, zppt = struct.unpack('>HB', read_buffer)
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length = length
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zppt = zppt
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numbytes = length - 3
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ippt = fptr.read(numbytes)
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return PPTsegment(zppt, ippt, length, offset)
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def _parse_ppm_segment(fptr):
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"""Parse the PPM segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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PPM segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(3)
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length, zppm = struct.unpack('>HB', read_buffer)
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numbytes = length - 3
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read_buffer = fptr.read(numbytes)
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return PPMsegment(zppm, read_buffer, length, offset)
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def _parse_crg_segment(fptr, csiz):
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"""Parse the CRG marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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CRG segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(2)
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length, = struct.unpack('>H', read_buffer)
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read_buffer = fptr.read(4 * csiz)
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data = struct.unpack('>' + 'HH' * csiz, read_buffer)
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xcrg = data[0::2]
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ycrg = data[1::2]
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return CRGsegment(xcrg, ycrg, length, offset)
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def _parse_eoc_segment(fptr):
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"""Parse the EOC marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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EOC Segment instance.
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"""
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offset = fptr.tell() - 2
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length = 0
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return EOCsegment(length, offset)
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def _parse_cme_segment(fptr):
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"""Parse the CME marker segment.
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Parameters
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----------
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fptr : file
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Open file object.
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Returns
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-------
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CME segment instance.
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"""
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offset = fptr.tell() - 2
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read_buffer = fptr.read(4)
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data = struct.unpack('>HH', read_buffer)
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length = data[0]
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rcme = data[1]
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ccme = fptr.read(length - 4)
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return CMEsegment(rcme, ccme, length, offset)
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def _parse_generic_segment(fptr, marker_id):
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"""Parse a generic marker segment.
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