def calcHeadCheckSumAdjustment(flavor, tables):
numTables = len(tables)
# build the sfnt header
searchRange, entrySelector, rangeShift = getSearchRange(numTables)
sfntDirectoryData = dict(sfntVersion=flavor,
numTables=numTables,
searchRange=searchRange,
entrySelector=entrySelector,
rangeShift=rangeShift)
# build the sfnt directory
directory = sstruct.pack(sfntDirectoryFormat, sfntDirectoryData)
for tag, entry in sorted(tables.items()):
entry = tables[tag]
sfntEntry = SFNTDirectoryEntry()
sfntEntry.tag = tag
sfntEntry.checkSum = entry["checkSum"]
sfntEntry.offset = entry["offset"]
sfntEntry.length = entry["length"]
directory += sfntEntry.toString()
# calculate the checkSumAdjustment
checkSums = [entry["checkSum"] for entry in tables.values()]
checkSums.append(calcChecksum(directory))
checkSumAdjustment = sum(checkSums)
checkSumAdjustment = (0xB1B0AFBA - checkSumAdjustment) & 0xffffffff
# done
return checkSumAdjustment
def _writeTableDirectory(self):
if self.verbose:
debugmsg("writing table directory")
self.file.seek(woffHeaderSize)
for tag, (index, entry, data) in sorted(self.tables.items()):
entry = sstruct.pack(woffDirectoryEntryFormat, entry)
self.file.write(entry)
def close(self):
if self.numTables != len(self.tables):
raise WOFFLibError(
"wrong number of tables; expected %d, found %d" %
(self.numTables, len(self.tables)))
# first, handle the checkSumAdjustment
if self.recalculateHeadChecksum and "head" in self.tables:
self._handleHeadChecksum()
# check the table directory conformance
for tag, (index, entry, data) in sorted(self.tables.items()):
self._checkTableConformance(entry, data)
# write the header
header = sstruct.pack(woffHeaderFormat, self)
self.file.seek(0)
self.file.write(header)
# update the directory offsets
offset = woffHeaderSize + (woffDirectoryEntrySize * self.numTables)
order = self._tableOrder()
for tag in order:
index, entry, data = self.tables[tag]
entry.offset = offset
offset += calc4BytePaddedLength(
entry.compLength) # ensure byte alignment
# write the directory
self._writeTableDirectory()
# write the table data
self._writeTableData()
# write the metadata
self._writeMetadata()
# write the private data
self._writePrivateData()
# write the header
self._writeHeader()
# go to the beginning of the file
self.file.seek(0)
def toString(self):
return sstruct.pack(woffDirectoryEntryFormat, self)
def _writeHeader(self):
header = sstruct.pack(woffHeaderFormat, self)
self.file.seek(0)
self.file.write(header)