/usr/lib/python2.7/dist-packages/FontTools/fontTools/ttLib/woff2.py is in fonttools 3.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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from fontTools.misc.py23 import *
import sys
import array
import struct
from collections import OrderedDict
from fontTools.misc import sstruct
from fontTools.misc.arrayTools import calcIntBounds
from fontTools.misc.textTools import pad
from fontTools.ttLib import (TTFont, TTLibError, getTableModule, getTableClass,
getSearchRange)
from fontTools.ttLib.sfnt import (SFNTReader, SFNTWriter, DirectoryEntry,
WOFFFlavorData, sfntDirectoryFormat, sfntDirectorySize, SFNTDirectoryEntry,
sfntDirectoryEntrySize, calcChecksum)
from fontTools.ttLib.tables import ttProgram
haveBrotli = False
try:
import brotli
haveBrotli = True
except ImportError:
pass
class WOFF2Reader(SFNTReader):
flavor = "woff2"
def __init__(self, file, checkChecksums=1, fontNumber=-1):
if not haveBrotli:
print('The WOFF2 decoder requires the Brotli Python extension, available at:\n'
'https://github.com/google/brotli', file=sys.stderr)
raise ImportError("No module named brotli")
self.file = file
signature = Tag(self.file.read(4))
if signature != b"wOF2":
raise TTLibError("Not a WOFF2 font (bad signature)")
self.file.seek(0)
self.DirectoryEntry = WOFF2DirectoryEntry
data = self.file.read(woff2DirectorySize)
if len(data) != woff2DirectorySize:
raise TTLibError('Not a WOFF2 font (not enough data)')
sstruct.unpack(woff2DirectoryFormat, data, self)
self.tables = OrderedDict()
offset = 0
for i in range(self.numTables):
entry = self.DirectoryEntry()
entry.fromFile(self.file)
tag = Tag(entry.tag)
self.tables[tag] = entry
entry.offset = offset
offset += entry.length
totalUncompressedSize = offset
compressedData = self.file.read(self.totalCompressedSize)
decompressedData = brotli.decompress(compressedData)
if len(decompressedData) != totalUncompressedSize:
raise TTLibError(
'unexpected size for decompressed font data: expected %d, found %d'
% (totalUncompressedSize, len(decompressedData)))
self.transformBuffer = BytesIO(decompressedData)
self.file.seek(0, 2)
if self.length != self.file.tell():
raise TTLibError("reported 'length' doesn't match the actual file size")
self.flavorData = WOFF2FlavorData(self)
# make empty TTFont to store data while reconstructing tables
self.ttFont = TTFont(recalcBBoxes=False, recalcTimestamp=False)
def __getitem__(self, tag):
"""Fetch the raw table data. Reconstruct transformed tables."""
entry = self.tables[Tag(tag)]
if not hasattr(entry, 'data'):
if tag in woff2TransformedTableTags:
entry.data = self.reconstructTable(tag)
else:
entry.data = entry.loadData(self.transformBuffer)
return entry.data
def reconstructTable(self, tag):
"""Reconstruct table named 'tag' from transformed data."""
if tag not in woff2TransformedTableTags:
raise TTLibError("transform for table '%s' is unknown" % tag)
entry = self.tables[Tag(tag)]
rawData = entry.loadData(self.transformBuffer)
if tag == 'glyf':
# no need to pad glyph data when reconstructing
padding = self.padding if hasattr(self, 'padding') else None
data = self._reconstructGlyf(rawData, padding)
elif tag == 'loca':
data = self._reconstructLoca()
else:
raise NotImplementedError
return data
def _reconstructGlyf(self, data, padding=None):
""" Return recostructed glyf table data, and set the corresponding loca's
locations. Optionally pad glyph offsets to the specified number of bytes.
"""
self.ttFont['loca'] = WOFF2LocaTable()
glyfTable = self.ttFont['glyf'] = WOFF2GlyfTable()
glyfTable.reconstruct(data, self.ttFont)
glyfTable.padding = padding
data = glyfTable.compile(self.ttFont)
return data
def _reconstructLoca(self):
""" Return reconstructed loca table data. """
if 'loca' not in self.ttFont:
# make sure glyf is reconstructed first
self.tables['glyf'].data = self.reconstructTable('glyf')
locaTable = self.ttFont['loca']
data = locaTable.compile(self.ttFont)
if len(data) != self.tables['loca'].origLength:
raise TTLibError(
"reconstructed 'loca' table doesn't match original size: "
"expected %d, found %d"
% (self.tables['loca'].origLength, len(data)))
return data
class WOFF2Writer(SFNTWriter):
flavor = "woff2"
def __init__(self, file, numTables, sfntVersion="\000\001\000\000",
flavor=None, flavorData=None):
if not haveBrotli:
print('The WOFF2 encoder requires the Brotli Python extension, available at:\n'
'https://github.com/google/brotli', file=sys.stderr)
raise ImportError("No module named brotli")
self.file = file
self.numTables = numTables
self.sfntVersion = Tag(sfntVersion)
self.flavorData = flavorData or WOFF2FlavorData()
self.directoryFormat = woff2DirectoryFormat
self.directorySize = woff2DirectorySize
self.DirectoryEntry = WOFF2DirectoryEntry
self.signature = Tag("wOF2")
self.nextTableOffset = 0
self.transformBuffer = BytesIO()
self.tables = OrderedDict()
# make empty TTFont to store data while normalising and transforming tables
self.ttFont = TTFont(recalcBBoxes=False, recalcTimestamp=False)
def __setitem__(self, tag, data):
"""Associate new entry named 'tag' with raw table data."""
if tag in self.tables:
raise TTLibError("cannot rewrite '%s' table" % tag)
if tag == 'DSIG':
# always drop DSIG table, since the encoding process can invalidate it
self.numTables -= 1
return
entry = self.DirectoryEntry()
entry.tag = Tag(tag)
entry.flags = getKnownTagIndex(entry.tag)
# WOFF2 table data are written to disk only on close(), after all tags
# have been specified
entry.data = data
self.tables[tag] = entry
def close(self):
""" All tags must have been specified. Now write the table data and directory.
"""
if len(self.tables) != self.numTables:
raise TTLibError("wrong number of tables; expected %d, found %d" % (self.numTables, len(self.tables)))
if self.sfntVersion in ("\x00\x01\x00\x00", "true"):
isTrueType = True
elif self.sfntVersion == "OTTO":
isTrueType = False
else:
raise TTLibError("Not a TrueType or OpenType font (bad sfntVersion)")
# The WOFF2 spec no longer requires the glyph offsets to be 4-byte aligned.
# However, the reference WOFF2 implementation still fails to reconstruct
# 'unpadded' glyf tables, therefore we need to 'normalise' them.
# See:
# https://github.com/khaledhosny/ots/issues/60
# https://github.com/google/woff2/issues/15
if isTrueType:
self._normaliseGlyfAndLoca(padding=4)
self._setHeadTransformFlag()
# To pass the legacy OpenType Sanitiser currently included in browsers,
# we must sort the table directory and data alphabetically by tag.
# See:
# https://github.com/google/woff2/pull/3
# https://lists.w3.org/Archives/Public/public-webfonts-wg/2015Mar/0000.html
# TODO(user): remove to match spec once browsers are on newer OTS
self.tables = OrderedDict(sorted(self.tables.items()))
self.totalSfntSize = self._calcSFNTChecksumsLengthsAndOffsets()
fontData = self._transformTables()
compressedFont = brotli.compress(fontData, mode=brotli.MODE_FONT)
self.totalCompressedSize = len(compressedFont)
self.length = self._calcTotalSize()
self.majorVersion, self.minorVersion = self._getVersion()
self.reserved = 0
directory = self._packTableDirectory()
self.file.seek(0)
self.file.write(pad(directory + compressedFont, size=4))
self._writeFlavorData()
def _normaliseGlyfAndLoca(self, padding=4):
""" Recompile glyf and loca tables, aligning glyph offsets to multiples of
'padding' size. Update the head table's 'indexToLocFormat' accordingly while
compiling loca.
"""
if self.sfntVersion == "OTTO":
return
for tag in ('maxp', 'head', 'loca', 'glyf'):
self._decompileTable(tag)
self.ttFont['glyf'].padding = padding
for tag in ('glyf', 'loca'):
self._compileTable(tag)
def _setHeadTransformFlag(self):
""" Set bit 11 of 'head' table flags to indicate that the font has undergone
a lossless modifying transform. Re-compile head table data."""
self._decompileTable('head')
self.ttFont['head'].flags |= (1 << 11)
self._compileTable('head')
def _decompileTable(self, tag):
""" Fetch table data, decompile it, and store it inside self.ttFont. """
tag = Tag(tag)
if tag not in self.tables:
raise TTLibError("missing required table: %s" % tag)
if self.ttFont.isLoaded(tag):
return
data = self.tables[tag].data
if tag == 'loca':
tableClass = WOFF2LocaTable
elif tag == 'glyf':
tableClass = WOFF2GlyfTable
else:
tableClass = getTableClass(tag)
table = tableClass(tag)
self.ttFont.tables[tag] = table
table.decompile(data, self.ttFont)
def _compileTable(self, tag):
""" Compile table and store it in its 'data' attribute. """
self.tables[tag].data = self.ttFont[tag].compile(self.ttFont)
def _calcSFNTChecksumsLengthsAndOffsets(self):
""" Compute the 'original' SFNT checksums, lengths and offsets for checksum
adjustment calculation. Return the total size of the uncompressed font.
"""
offset = sfntDirectorySize + sfntDirectoryEntrySize * len(self.tables)
for tag, entry in self.tables.items():
data = entry.data
entry.origOffset = offset
entry.origLength = len(data)
if tag == 'head':
entry.checkSum = calcChecksum(data[:8] + b'\0\0\0\0' + data[12:])
else:
entry.checkSum = calcChecksum(data)
offset += (entry.origLength + 3) & ~3
return offset
def _transformTables(self):
"""Return transformed font data."""
for tag, entry in self.tables.items():
if tag in woff2TransformedTableTags:
data = self.transformTable(tag)
else:
data = entry.data
entry.offset = self.nextTableOffset
entry.saveData(self.transformBuffer, data)
self.nextTableOffset += entry.length
self.writeMasterChecksum()
fontData = self.transformBuffer.getvalue()
return fontData
def transformTable(self, tag):
"""Return transformed table data."""
if tag not in woff2TransformedTableTags:
raise TTLibError("Transform for table '%s' is unknown" % tag)
if tag == "loca":
data = b""
elif tag == "glyf":
for tag in ('maxp', 'head', 'loca', 'glyf'):
self._decompileTable(tag)
glyfTable = self.ttFont['glyf']
data = glyfTable.transform(self.ttFont)
else:
raise NotImplementedError
return data
def _calcMasterChecksum(self):
"""Calculate checkSumAdjustment."""
tags = list(self.tables.keys())
checksums = []
for i in range(len(tags)):
checksums.append(self.tables[tags[i]].checkSum)
# Create a SFNT directory for checksum calculation purposes
self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables, 16)
directory = sstruct.pack(sfntDirectoryFormat, self)
tables = sorted(self.tables.items())
for tag, entry in tables:
sfntEntry = SFNTDirectoryEntry()
sfntEntry.tag = entry.tag
sfntEntry.checkSum = entry.checkSum
sfntEntry.offset = entry.origOffset
sfntEntry.length = entry.origLength
directory = directory + sfntEntry.toString()
directory_end = sfntDirectorySize + len(self.tables) * sfntDirectoryEntrySize
assert directory_end == len(directory)
checksums.append(calcChecksum(directory))
checksum = sum(checksums) & 0xffffffff
# BiboAfba!
checksumadjustment = (0xB1B0AFBA - checksum) & 0xffffffff
return checksumadjustment
def writeMasterChecksum(self):
"""Write checkSumAdjustment to the transformBuffer."""
checksumadjustment = self._calcMasterChecksum()
self.transformBuffer.seek(self.tables['head'].offset + 8)
self.transformBuffer.write(struct.pack(">L", checksumadjustment))
def _calcTotalSize(self):
"""Calculate total size of WOFF2 font, including any meta- and/or private data."""
offset = self.directorySize
for entry in self.tables.values():
offset += len(entry.toString())
offset += self.totalCompressedSize
offset = (offset + 3) & ~3
offset = self._calcFlavorDataOffsetsAndSize(offset)
return offset
def _calcFlavorDataOffsetsAndSize(self, start):
"""Calculate offsets and lengths for any meta- and/or private data."""
offset = start
data = self.flavorData
if data.metaData:
self.metaOrigLength = len(data.metaData)
self.metaOffset = offset
self.compressedMetaData = brotli.compress(
data.metaData, mode=brotli.MODE_TEXT)
self.metaLength = len(self.compressedMetaData)
offset += self.metaLength
else:
self.metaOffset = self.metaLength = self.metaOrigLength = 0
self.compressedMetaData = b""
if data.privData:
# make sure private data is padded to 4-byte boundary
offset = (offset + 3) & ~3
self.privOffset = offset
self.privLength = len(data.privData)
offset += self.privLength
else:
self.privOffset = self.privLength = 0
return offset
def _getVersion(self):
"""Return the WOFF2 font's (majorVersion, minorVersion) tuple."""
data = self.flavorData
if data.majorVersion is not None and data.minorVersion is not None:
return data.majorVersion, data.minorVersion
else:
# if None, return 'fontRevision' from 'head' table
if 'head' in self.tables:
return struct.unpack(">HH", self.tables['head'].data[4:8])
else:
return 0, 0
def _packTableDirectory(self):
"""Return WOFF2 table directory data."""
directory = sstruct.pack(self.directoryFormat, self)
for entry in self.tables.values():
directory = directory + entry.toString()
return directory
def _writeFlavorData(self):
"""Write metadata and/or private data using appropiate padding."""
compressedMetaData = self.compressedMetaData
privData = self.flavorData.privData
if compressedMetaData and privData:
compressedMetaData = pad(compressedMetaData, size=4)
if compressedMetaData:
self.file.seek(self.metaOffset)
assert self.file.tell() == self.metaOffset
self.file.write(compressedMetaData)
if privData:
self.file.seek(self.privOffset)
assert self.file.tell() == self.privOffset
self.file.write(privData)
def reordersTables(self):
return True
# -- woff2 directory helpers and cruft
woff2DirectoryFormat = """
> # big endian
signature: 4s # "wOF2"
sfntVersion: 4s
length: L # total woff2 file size
numTables: H # number of tables
reserved: H # set to 0
totalSfntSize: L # uncompressed size
totalCompressedSize: L # compressed size
majorVersion: H # major version of WOFF file
minorVersion: H # minor version of WOFF file
metaOffset: L # offset to metadata block
metaLength: L # length of compressed metadata
metaOrigLength: L # length of uncompressed metadata
privOffset: L # offset to private data block
privLength: L # length of private data block
"""
woff2DirectorySize = sstruct.calcsize(woff2DirectoryFormat)
woff2KnownTags = (
"cmap", "head", "hhea", "hmtx", "maxp", "name", "OS/2", "post", "cvt ",
"fpgm", "glyf", "loca", "prep", "CFF ", "VORG", "EBDT", "EBLC", "gasp",
"hdmx", "kern", "LTSH", "PCLT", "VDMX", "vhea", "vmtx", "BASE", "GDEF",
"GPOS", "GSUB", "EBSC", "JSTF", "MATH", "CBDT", "CBLC", "COLR", "CPAL",
"SVG ", "sbix", "acnt", "avar", "bdat", "bloc", "bsln", "cvar", "fdsc",
"feat", "fmtx", "fvar", "gvar", "hsty", "just", "lcar", "mort", "morx",
"opbd", "prop", "trak", "Zapf", "Silf", "Glat", "Gloc", "Feat", "Sill")
woff2FlagsFormat = """
> # big endian
flags: B # table type and flags
"""
woff2FlagsSize = sstruct.calcsize(woff2FlagsFormat)
woff2UnknownTagFormat = """
> # big endian
tag: 4s # 4-byte tag (optional)
"""
woff2UnknownTagSize = sstruct.calcsize(woff2UnknownTagFormat)
woff2UnknownTagIndex = 0x3F
woff2Base128MaxSize = 5
woff2DirectoryEntryMaxSize = woff2FlagsSize + woff2UnknownTagSize + 2 * woff2Base128MaxSize
woff2TransformedTableTags = ('glyf', 'loca')
woff2GlyfTableFormat = """
> # big endian
version: L # = 0x00000000
numGlyphs: H # Number of glyphs
indexFormat: H # Offset format for loca table
nContourStreamSize: L # Size of nContour stream
nPointsStreamSize: L # Size of nPoints stream
flagStreamSize: L # Size of flag stream
glyphStreamSize: L # Size of glyph stream
compositeStreamSize: L # Size of composite stream
bboxStreamSize: L # Comnined size of bboxBitmap and bboxStream
instructionStreamSize: L # Size of instruction stream
"""
woff2GlyfTableFormatSize = sstruct.calcsize(woff2GlyfTableFormat)
bboxFormat = """
> # big endian
xMin: h
yMin: h
xMax: h
yMax: h
"""
def getKnownTagIndex(tag):
"""Return index of 'tag' in woff2KnownTags list. Return 63 if not found."""
for i in range(len(woff2KnownTags)):
if tag == woff2KnownTags[i]:
return i
return woff2UnknownTagIndex
class WOFF2DirectoryEntry(DirectoryEntry):
def fromFile(self, file):
pos = file.tell()
data = file.read(woff2DirectoryEntryMaxSize)
left = self.fromString(data)
consumed = len(data) - len(left)
file.seek(pos + consumed)
def fromString(self, data):
if len(data) < 1:
raise TTLibError("can't read table 'flags': not enough data")
dummy, data = sstruct.unpack2(woff2FlagsFormat, data, self)
if self.flags & 0x3F == 0x3F:
# if bits [0..5] of the flags byte == 63, read a 4-byte arbitrary tag value
if len(data) < woff2UnknownTagSize:
raise TTLibError("can't read table 'tag': not enough data")
dummy, data = sstruct.unpack2(woff2UnknownTagFormat, data, self)
else:
# otherwise, tag is derived from a fixed 'Known Tags' table
self.tag = woff2KnownTags[self.flags & 0x3F]
self.tag = Tag(self.tag)
if self.flags & 0xC0 != 0:
raise TTLibError('bits 6-7 are reserved and must be 0')
self.origLength, data = unpackBase128(data)
self.length = self.origLength
if self.tag in woff2TransformedTableTags:
self.length, data = unpackBase128(data)
if self.tag == 'loca' and self.length != 0:
raise TTLibError(
"the transformLength of the 'loca' table must be 0")
# return left over data
return data
def toString(self):
data = bytechr(self.flags)
if (self.flags & 0x3F) == 0x3F:
data += struct.pack('>4s', self.tag.tobytes())
data += packBase128(self.origLength)
if self.tag in woff2TransformedTableTags:
data += packBase128(self.length)
return data
class WOFF2LocaTable(getTableClass('loca')):
"""Same as parent class. The only difference is that it attempts to preserve
the 'indexFormat' as encoded in the WOFF2 glyf table.
"""
def __init__(self, tag=None):
self.tableTag = Tag(tag or 'loca')
def compile(self, ttFont):
try:
max_location = max(self.locations)
except AttributeError:
self.set([])
max_location = 0
if 'glyf' in ttFont and hasattr(ttFont['glyf'], 'indexFormat'):
# copile loca using the indexFormat specified in the WOFF2 glyf table
indexFormat = ttFont['glyf'].indexFormat
if indexFormat == 0:
if max_location >= 0x20000:
raise TTLibError("indexFormat is 0 but local offsets > 0x20000")
if not all(l % 2 == 0 for l in self.locations):
raise TTLibError("indexFormat is 0 but local offsets not multiples of 2")
locations = array.array("H")
for i in range(len(self.locations)):
locations.append(self.locations[i] // 2)
else:
locations = array.array("I", self.locations)
if sys.byteorder != "big":
locations.byteswap()
data = locations.tostring()
else:
# use the most compact indexFormat given the current glyph offsets
data = super(WOFF2LocaTable, self).compile(ttFont)
return data
class WOFF2GlyfTable(getTableClass('glyf')):
"""Decoder/Encoder for WOFF2 'glyf' table transform."""
subStreams = (
'nContourStream', 'nPointsStream', 'flagStream', 'glyphStream',
'compositeStream', 'bboxStream', 'instructionStream')
def __init__(self, tag=None):
self.tableTag = Tag(tag or 'glyf')
def reconstruct(self, data, ttFont):
""" Decompile transformed 'glyf' data. """
inputDataSize = len(data)
if inputDataSize < woff2GlyfTableFormatSize:
raise TTLibError("not enough 'glyf' data")
dummy, data = sstruct.unpack2(woff2GlyfTableFormat, data, self)
offset = woff2GlyfTableFormatSize
for stream in self.subStreams:
size = getattr(self, stream + 'Size')
setattr(self, stream, data[:size])
data = data[size:]
offset += size
if offset != inputDataSize:
raise TTLibError(
"incorrect size of transformed 'glyf' table: expected %d, received %d bytes"
% (offset, inputDataSize))
bboxBitmapSize = ((self.numGlyphs + 31) >> 5) << 2
bboxBitmap = self.bboxStream[:bboxBitmapSize]
self.bboxBitmap = array.array('B', bboxBitmap)
self.bboxStream = self.bboxStream[bboxBitmapSize:]
self.nContourStream = array.array("h", self.nContourStream)
if sys.byteorder != "big":
self.nContourStream.byteswap()
assert len(self.nContourStream) == self.numGlyphs
if 'head' in ttFont:
ttFont['head'].indexToLocFormat = self.indexFormat
try:
self.glyphOrder = ttFont.getGlyphOrder()
except:
self.glyphOrder = None
if self.glyphOrder is None:
self.glyphOrder = [".notdef"]
self.glyphOrder.extend(["glyph%.5d" % i for i in range(1, self.numGlyphs)])
else:
if len(self.glyphOrder) != self.numGlyphs:
raise TTLibError(
"incorrect glyphOrder: expected %d glyphs, found %d" %
(len(self.glyphOrder), self.numGlyphs))
glyphs = self.glyphs = {}
for glyphID, glyphName in enumerate(self.glyphOrder):
glyph = self._decodeGlyph(glyphID)
glyphs[glyphName] = glyph
def transform(self, ttFont):
""" Return transformed 'glyf' data """
self.numGlyphs = len(self.glyphs)
if not hasattr(self, "glyphOrder"):
try:
self.glyphOrder = ttFont.getGlyphOrder()
except:
self.glyphOrder = None
if self.glyphOrder is None:
self.glyphOrder = [".notdef"]
self.glyphOrder.extend(["glyph%.5d" % i for i in range(1, self.numGlyphs)])
if len(self.glyphOrder) != self.numGlyphs:
raise TTLibError(
"incorrect glyphOrder: expected %d glyphs, found %d" %
(len(self.glyphOrder), self.numGlyphs))
if 'maxp' in ttFont:
ttFont['maxp'].numGlyphs = self.numGlyphs
self.indexFormat = ttFont['head'].indexToLocFormat
for stream in self.subStreams:
setattr(self, stream, b"")
bboxBitmapSize = ((self.numGlyphs + 31) >> 5) << 2
self.bboxBitmap = array.array('B', [0]*bboxBitmapSize)
for glyphID in range(self.numGlyphs):
self._encodeGlyph(glyphID)
self.bboxStream = self.bboxBitmap.tostring() + self.bboxStream
for stream in self.subStreams:
setattr(self, stream + 'Size', len(getattr(self, stream)))
self.version = 0
data = sstruct.pack(woff2GlyfTableFormat, self)
data += bytesjoin([getattr(self, s) for s in self.subStreams])
return data
def _decodeGlyph(self, glyphID):
glyph = getTableModule('glyf').Glyph()
glyph.numberOfContours = self.nContourStream[glyphID]
if glyph.numberOfContours == 0:
return glyph
elif glyph.isComposite():
self._decodeComponents(glyph)
else:
self._decodeCoordinates(glyph)
self._decodeBBox(glyphID, glyph)
return glyph
def _decodeComponents(self, glyph):
data = self.compositeStream
glyph.components = []
more = 1
haveInstructions = 0
while more:
component = getTableModule('glyf').GlyphComponent()
more, haveInstr, data = component.decompile(data, self)
haveInstructions = haveInstructions | haveInstr
glyph.components.append(component)
self.compositeStream = data
if haveInstructions:
self._decodeInstructions(glyph)
def _decodeCoordinates(self, glyph):
data = self.nPointsStream
endPtsOfContours = []
endPoint = -1
for i in range(glyph.numberOfContours):
ptsOfContour, data = unpack255UShort(data)
endPoint += ptsOfContour
endPtsOfContours.append(endPoint)
glyph.endPtsOfContours = endPtsOfContours
self.nPointsStream = data
self._decodeTriplets(glyph)
self._decodeInstructions(glyph)
def _decodeInstructions(self, glyph):
glyphStream = self.glyphStream
instructionStream = self.instructionStream
instructionLength, glyphStream = unpack255UShort(glyphStream)
glyph.program = ttProgram.Program()
glyph.program.fromBytecode(instructionStream[:instructionLength])
self.glyphStream = glyphStream
self.instructionStream = instructionStream[instructionLength:]
def _decodeBBox(self, glyphID, glyph):
haveBBox = bool(self.bboxBitmap[glyphID >> 3] & (0x80 >> (glyphID & 7)))
if glyph.isComposite() and not haveBBox:
raise TTLibError('no bbox values for composite glyph %d' % glyphID)
if haveBBox:
dummy, self.bboxStream = sstruct.unpack2(bboxFormat, self.bboxStream, glyph)
else:
glyph.recalcBounds(self)
def _decodeTriplets(self, glyph):
def withSign(flag, baseval):
assert 0 <= baseval and baseval < 65536, 'integer overflow'
return baseval if flag & 1 else -baseval
nPoints = glyph.endPtsOfContours[-1] + 1
flagSize = nPoints
if flagSize > len(self.flagStream):
raise TTLibError("not enough 'flagStream' data")
flagsData = self.flagStream[:flagSize]
self.flagStream = self.flagStream[flagSize:]
flags = array.array('B', flagsData)
triplets = array.array('B', self.glyphStream)
nTriplets = len(triplets)
assert nPoints <= nTriplets
x = 0
y = 0
glyph.coordinates = getTableModule('glyf').GlyphCoordinates.zeros(nPoints)
glyph.flags = array.array("B")
tripletIndex = 0
for i in range(nPoints):
flag = flags[i]
onCurve = not bool(flag >> 7)
flag &= 0x7f
if flag < 84:
nBytes = 1
elif flag < 120:
nBytes = 2
elif flag < 124:
nBytes = 3
else:
nBytes = 4
assert ((tripletIndex + nBytes) <= nTriplets)
if flag < 10:
dx = 0
dy = withSign(flag, ((flag & 14) << 7) + triplets[tripletIndex])
elif flag < 20:
dx = withSign(flag, (((flag - 10) & 14) << 7) + triplets[tripletIndex])
dy = 0
elif flag < 84:
b0 = flag - 20
b1 = triplets[tripletIndex]
dx = withSign(flag, 1 + (b0 & 0x30) + (b1 >> 4))
dy = withSign(flag >> 1, 1 + ((b0 & 0x0c) << 2) + (b1 & 0x0f))
elif flag < 120:
b0 = flag - 84
dx = withSign(flag, 1 + ((b0 // 12) << 8) + triplets[tripletIndex])
dy = withSign(flag >> 1,
1 + (((b0 % 12) >> 2) << 8) + triplets[tripletIndex + 1])
elif flag < 124:
b2 = triplets[tripletIndex + 1]
dx = withSign(flag, (triplets[tripletIndex] << 4) + (b2 >> 4))
dy = withSign(flag >> 1,
((b2 & 0x0f) << 8) + triplets[tripletIndex + 2])
else:
dx = withSign(flag,
(triplets[tripletIndex] << 8) + triplets[tripletIndex + 1])
dy = withSign(flag >> 1,
(triplets[tripletIndex + 2] << 8) + triplets[tripletIndex + 3])
tripletIndex += nBytes
x += dx
y += dy
glyph.coordinates[i] = (x, y)
glyph.flags.append(int(onCurve))
bytesConsumed = tripletIndex
self.glyphStream = self.glyphStream[bytesConsumed:]
def _encodeGlyph(self, glyphID):
glyphName = self.getGlyphName(glyphID)
glyph = self[glyphName]
self.nContourStream += struct.pack(">h", glyph.numberOfContours)
if glyph.numberOfContours == 0:
return
elif glyph.isComposite():
self._encodeComponents(glyph)
else:
self._encodeCoordinates(glyph)
self._encodeBBox(glyphID, glyph)
def _encodeComponents(self, glyph):
lastcomponent = len(glyph.components) - 1
more = 1
haveInstructions = 0
for i in range(len(glyph.components)):
if i == lastcomponent:
haveInstructions = hasattr(glyph, "program")
more = 0
component = glyph.components[i]
self.compositeStream += component.compile(more, haveInstructions, self)
if haveInstructions:
self._encodeInstructions(glyph)
def _encodeCoordinates(self, glyph):
lastEndPoint = -1
for endPoint in glyph.endPtsOfContours:
ptsOfContour = endPoint - lastEndPoint
self.nPointsStream += pack255UShort(ptsOfContour)
lastEndPoint = endPoint
self._encodeTriplets(glyph)
self._encodeInstructions(glyph)
def _encodeInstructions(self, glyph):
instructions = glyph.program.getBytecode()
self.glyphStream += pack255UShort(len(instructions))
self.instructionStream += instructions
def _encodeBBox(self, glyphID, glyph):
assert glyph.numberOfContours != 0, "empty glyph has no bbox"
if not glyph.isComposite():
# for simple glyphs, compare the encoded bounding box info with the calculated
# values, and if they match omit the bounding box info
currentBBox = glyph.xMin, glyph.yMin, glyph.xMax, glyph.yMax
calculatedBBox = calcIntBounds(glyph.coordinates)
if currentBBox == calculatedBBox:
return
self.bboxBitmap[glyphID >> 3] |= 0x80 >> (glyphID & 7)
self.bboxStream += sstruct.pack(bboxFormat, glyph)
def _encodeTriplets(self, glyph):
assert len(glyph.coordinates) == len(glyph.flags)
coordinates = glyph.coordinates.copy()
coordinates.absoluteToRelative()
flags = array.array('B')
triplets = array.array('B')
for i in range(len(coordinates)):
onCurve = glyph.flags[i]
x, y = coordinates[i]
absX = abs(x)
absY = abs(y)
onCurveBit = 0 if onCurve else 128
xSignBit = 0 if (x < 0) else 1
ySignBit = 0 if (y < 0) else 1
xySignBits = xSignBit + 2 * ySignBit
if x == 0 and absY < 1280:
flags.append(onCurveBit + ((absY & 0xf00) >> 7) + ySignBit)
triplets.append(absY & 0xff)
elif y == 0 and absX < 1280:
flags.append(onCurveBit + 10 + ((absX & 0xf00) >> 7) + xSignBit)
triplets.append(absX & 0xff)
elif absX < 65 and absY < 65:
flags.append(onCurveBit + 20 + ((absX - 1) & 0x30) + (((absY - 1) & 0x30) >> 2) + xySignBits)
triplets.append((((absX - 1) & 0xf) << 4) | ((absY - 1) & 0xf))
elif absX < 769 and absY < 769:
flags.append(onCurveBit + 84 + 12 * (((absX - 1) & 0x300) >> 8) + (((absY - 1) & 0x300) >> 6) + xySignBits)
triplets.append((absX - 1) & 0xff)
triplets.append((absY - 1) & 0xff)
elif absX < 4096 and absY < 4096:
flags.append(onCurveBit + 120 + xySignBits)
triplets.append(absX >> 4)
triplets.append(((absX & 0xf) << 4) | (absY >> 8))
triplets.append(absY & 0xff)
else:
flags.append(onCurveBit + 124 + xySignBits)
triplets.append(absX >> 8)
triplets.append(absX & 0xff)
triplets.append(absY >> 8)
triplets.append(absY & 0xff)
self.flagStream += flags.tostring()
self.glyphStream += triplets.tostring()
class WOFF2FlavorData(WOFFFlavorData):
Flavor = 'woff2'
def __init__(self, reader=None):
if not haveBrotli:
raise ImportError("No module named brotli")
self.majorVersion = None
self.minorVersion = None
self.metaData = None
self.privData = None
if reader:
self.majorVersion = reader.majorVersion
self.minorVersion = reader.minorVersion
if reader.metaLength:
reader.file.seek(reader.metaOffset)
rawData = reader.file.read(reader.metaLength)
assert len(rawData) == reader.metaLength
data = brotli.decompress(rawData)
assert len(data) == reader.metaOrigLength
self.metaData = data
if reader.privLength:
reader.file.seek(reader.privOffset)
data = reader.file.read(reader.privLength)
assert len(data) == reader.privLength
self.privData = data
def unpackBase128(data):
r""" Read one to five bytes from UIntBase128-encoded input string, and return
a tuple containing the decoded integer plus any leftover data.
>>> unpackBase128(b'\x3f\x00\x00') == (63, b"\x00\x00")
True
>>> unpackBase128(b'\x8f\xff\xff\xff\x7f')[0] == 4294967295
True
>>> unpackBase128(b'\x80\x80\x3f') # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TTLibError: UIntBase128 value must not start with leading zeros
>>> unpackBase128(b'\x8f\xff\xff\xff\xff\x7f')[0] # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TTLibError: UIntBase128-encoded sequence is longer than 5 bytes
>>> unpackBase128(b'\x90\x80\x80\x80\x00')[0] # doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TTLibError: UIntBase128 value exceeds 2**32-1
"""
if len(data) == 0:
raise TTLibError('not enough data to unpack UIntBase128')
result = 0
if byteord(data[0]) == 0x80:
# font must be rejected if UIntBase128 value starts with 0x80
raise TTLibError('UIntBase128 value must not start with leading zeros')
for i in range(woff2Base128MaxSize):
if len(data) == 0:
raise TTLibError('not enough data to unpack UIntBase128')
code = byteord(data[0])
data = data[1:]
# if any of the top seven bits are set then we're about to overflow
if result & 0xFE000000:
raise TTLibError('UIntBase128 value exceeds 2**32-1')
# set current value = old value times 128 bitwise-or (byte bitwise-and 127)
result = (result << 7) | (code & 0x7f)
# repeat until the most significant bit of byte is false
if (code & 0x80) == 0:
# return result plus left over data
return result, data
# make sure not to exceed the size bound
raise TTLibError('UIntBase128-encoded sequence is longer than 5 bytes')
def base128Size(n):
""" Return the length in bytes of a UIntBase128-encoded sequence with value n.
>>> base128Size(0)
1
>>> base128Size(24567)
3
>>> base128Size(2**32-1)
5
"""
assert n >= 0
size = 1
while n >= 128:
size += 1
n >>= 7
return size
def packBase128(n):
r""" Encode unsigned integer in range 0 to 2**32-1 (inclusive) to a string of
bytes using UIntBase128 variable-length encoding. Produce the shortest possible
encoding.
>>> packBase128(63) == b"\x3f"
True
>>> packBase128(2**32-1) == b'\x8f\xff\xff\xff\x7f'
True
"""
if n < 0 or n >= 2**32:
raise TTLibError(
"UIntBase128 format requires 0 <= integer <= 2**32-1")
data = b''
size = base128Size(n)
for i in range(size):
b = (n >> (7 * (size - i - 1))) & 0x7f
if i < size - 1:
b |= 0x80
data += struct.pack('B', b)
return data
def unpack255UShort(data):
""" Read one to three bytes from 255UInt16-encoded input string, and return a
tuple containing the decoded integer plus any leftover data.
>>> unpack255UShort(bytechr(252))[0]
252
Note that some numbers (e.g. 506) can have multiple encodings:
>>> unpack255UShort(struct.pack("BB", 254, 0))[0]
506
>>> unpack255UShort(struct.pack("BB", 255, 253))[0]
506
>>> unpack255UShort(struct.pack("BBB", 253, 1, 250))[0]
506
"""
code = byteord(data[:1])
data = data[1:]
if code == 253:
# read two more bytes as an unsigned short
if len(data) < 2:
raise TTLibError('not enough data to unpack 255UInt16')
result, = struct.unpack(">H", data[:2])
data = data[2:]
elif code == 254:
# read another byte, plus 253 * 2
if len(data) == 0:
raise TTLibError('not enough data to unpack 255UInt16')
result = byteord(data[:1])
result += 506
data = data[1:]
elif code == 255:
# read another byte, plus 253
if len(data) == 0:
raise TTLibError('not enough data to unpack 255UInt16')
result = byteord(data[:1])
result += 253
data = data[1:]
else:
# leave as is if lower than 253
result = code
# return result plus left over data
return result, data
def pack255UShort(value):
r""" Encode unsigned integer in range 0 to 65535 (inclusive) to a bytestring
using 255UInt16 variable-length encoding.
>>> pack255UShort(252) == b'\xfc'
True
>>> pack255UShort(506) == b'\xfe\x00'
True
>>> pack255UShort(762) == b'\xfd\x02\xfa'
True
"""
if value < 0 or value > 0xFFFF:
raise TTLibError(
"255UInt16 format requires 0 <= integer <= 65535")
if value < 253:
return struct.pack(">B", value)
elif value < 506:
return struct.pack(">BB", 255, value - 253)
elif value < 762:
return struct.pack(">BB", 254, value - 506)
else:
return struct.pack(">BH", 253, value)
if __name__ == "__main__":
import doctest
sys.exit(doctest.testmod().failed)
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