def _testJunkAtTheBeginningOfTheFile(header):
"""
>>> test = dict(numTables=5, searchRange=64, entrySelector=2, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
False
>>> test = dict(numTables=5, searchRange=0, entrySelector=2, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
>>> test = dict(numTables=5, searchRange=64, entrySelector=0, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
>>> test = dict(numTables=5, searchRange=64, entrySelector=2, rangeShift=0)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
"""
errors = []
numTables = header["numTables"]
searchRange, entrySelector, rangeShift = getSearchRange(numTables)
if header["searchRange"] != searchRange:
errors.append("The searchRange value is incorrect.")
if header["entrySelector"] != entrySelector:
errors.append("The entrySelector value is incorrect.")
if header["rangeShift"] != rangeShift:
errors.append("The rangeShift value is incorrect.")
return errors
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 _testJunkAtTheBeginningOfTheFile(header):
"""
>>> test = dict(numTables=5, searchRange=64, entrySelector=2, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
False
>>> test = dict(numTables=5, searchRange=0, entrySelector=2, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
>>> test = dict(numTables=5, searchRange=64, entrySelector=0, rangeShift=16)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
>>> test = dict(numTables=5, searchRange=64, entrySelector=2, rangeShift=0)
>>> bool(_testJunkAtTheBeginningOfTheFile(test))
True
"""
errors = []
numTables = header["numTables"]
searchRange, entrySelector, rangeShift = getSearchRange(numTables)
if header["searchRange"] != searchRange:
errors.append("The searchRange value is incorrect.")
if header["entrySelector"] != entrySelector:
errors.append("The entrySelector value is incorrect.")
if header["rangeShift"] != rangeShift:
errors.append("The rangeShift value is incorrect.")
return errors
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 packSFNT(header, directory, tableData, flavor="cff",
calcCheckSum=True, applyPadding=True, sortDirectory=True,
searchRange=None, entrySelector=None, rangeShift=None):
# update the checkSum
if calcCheckSum:
if flavor == "cff":
f = "OTTO"
else:
f = "\000\001\000\000"
calcHeadCheckSumAdjustmentSFNT(directory, tableData, flavor=f)
# update the header
cSearchRange, cEntrySelector, cRangeShift = getSearchRange(len(directory))
if searchRange is None:
searchRange = cSearchRange
if entrySelector is None:
entrySelector = cEntrySelector
if rangeShift is None:
rangeShift = cRangeShift
if flavor == "cff":
header["sfntVersion"] = "OTTO"
else:
header["sfntVersion"] = "\000\001\000\000"
header["searchRange"] = searchRange
header["entrySelector"] = entrySelector
header["rangeShift"] = rangeShift
# version and num tables should already be set
sfntData = sstruct.pack(sfntDirectoryFormat, header)
# compile the directory
sfntDirectoryEntries = {}
entryOrder = []
for entry in directory:
sfntEntry = SFNTDirectoryEntry()
sfntEntry.tag = entry["tag"]
sfntEntry.checkSum = entry["checksum"]
sfntEntry.offset = entry["offset"]
sfntEntry.length = entry["length"]
sfntDirectoryEntries[entry["tag"]] = sfntEntry
entryOrder.append(entry["tag"])
if sortDirectory:
entryOrder = sorted(entryOrder)
for tag in entryOrder:
entry = sfntDirectoryEntries[tag]
sfntData += entry.toString()
# compile the data
directory = [(entry["offset"], entry["tag"]) for entry in directory]
for o, tag in sorted(directory):
data = tableData[tag]
if applyPadding:
data = padData(data)
sfntData += data
# done
return sfntData
def calcHeadCheckSumAdjustmentSFNT(directory, tableData, flavor=None):
"""
Set the checkSumAdjustment in the head table data.
Grumble.
"""
# if the flavor is None, guess.
if flavor is None:
flavor = "\000\001\000\000"
for entry in directory:
if entry["tag"] == "CFF ":
flavor = "OTTO"
break
assert flavor in ("OTTO", "\000\001\000\000")
# make the sfnt header
searchRange, entrySelector, rangeShift = getSearchRange(len(directory))
sfntHeaderData = dict(sfntVersion=flavor,
numTables=len(directory),
searchRange=searchRange,
entrySelector=entrySelector,
rangeShift=rangeShift)
sfntData = sstruct.pack(sfntDirectoryFormat, sfntHeaderData)
# make a SFNT table directory
directory = [(entry["tag"], entry) for entry in directory]
for tag, entry in sorted(directory):
sfntEntry = SFNTDirectoryEntry()
sfntEntry.tag = entry["tag"]
sfntEntry.checkSum = entry["checksum"]
sfntEntry.offset = entry["offset"]
sfntEntry.length = entry["length"]
sfntData += sfntEntry.toString()
# calculate the checksum
sfntDataChecksum = calcChecksum(sfntData)
# gather all of the checksums
checksums = [entry["checksum"] for o, entry in directory]
checksums.append(sfntDataChecksum)
# calculate the checksum
checkSumAdjustment = sum(checksums)
checkSumAdjustment = (0xB1B0AFBA - checkSumAdjustment) & 0xffffffff
# set the value in the head table
headTableData = tableData["head"]
newHeadTableData = headTableData[:8]
newHeadTableData += struct.pack(">L", checkSumAdjustment)
newHeadTableData += headTableData[12:]
tableData["head"] = newHeadTableData
