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[sfnt] fix WOFF checksum adjustment calculation

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Use 'origLength' and 'origChecksum', instead of 'length' and
'checksum', to calculate the checksum adjustment of WOFF.
This commit is contained in:
Cosimo Lupo 2015-04-01 10:25:06 +01:00
parent 0bf67b50bd
commit 4c4c65fac0
1 changed files with 13 additions and 6 deletions
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17
Lib/fontTools/ttLib/sfnt.py
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@ -111,6 +111,9 @@ class SFNTWriter(object):
self.DirectoryEntry = WOFFDirectoryEntry self.DirectoryEntry = WOFFDirectoryEntry
self.signature = "wOFF" self.signature = "wOFF"
# to calculate WOFF checksum adjustment, we also need the original SFNT offsets
self.origNextTableOffset = sfntDirectorySize + numTables * sfntDirectoryEntrySize
else: else:
assert not self.flavor, "Unknown flavor '%s'" % self.flavor assert not self.flavor, "Unknown flavor '%s'" % self.flavor
self.directoryFormat = sfntDirectoryFormat self.directoryFormat = sfntDirectoryFormat
@ -130,7 +133,7 @@ class SFNTWriter(object):
"""Write raw table data to disk.""" """Write raw table data to disk."""
if tag in self.tables: if tag in self.tables:
from fontTools import ttLib from fontTools import ttLib
raise ttLib.TTLibError("cannot rewrite '%s' table: length does not match directory entry" % tag) raise ttLib.TTLibError("cannot rewrite '%s' table" % tag)
entry = self.DirectoryEntry() entry = self.DirectoryEntry()
entry.tag = tag entry.tag = tag
@ -143,6 +146,10 @@ class SFNTWriter(object):
entry.checkSum = calcChecksum(data) entry.checkSum = calcChecksum(data)
entry.saveData(self.file, data) entry.saveData(self.file, data)
if self.flavor == "woff":
entry.origOffset = self.origNextTableOffset
self.origNextTableOffset += (entry.origLength + 3) & ~3
self.nextTableOffset = self.nextTableOffset + ((entry.length + 3) & ~3) self.nextTableOffset = self.nextTableOffset + ((entry.length + 3) & ~3)
# Add NUL bytes to pad the table data to a 4-byte boundary. # Add NUL bytes to pad the table data to a 4-byte boundary.
# Don't depend on f.seek() as we need to add the padding even if no # Don't depend on f.seek() as we need to add the padding even if no
@ -228,8 +235,6 @@ class SFNTWriter(object):
for i in range(len(tags)): for i in range(len(tags)):
checksums.append(self.tables[tags[i]].checkSum) checksums.append(self.tables[tags[i]].checkSum)
# TODO(behdad) I'm fairly sure the checksum for woff is not working correctly.
# Haven't debugged.
if self.DirectoryEntry != SFNTDirectoryEntry: if self.DirectoryEntry != SFNTDirectoryEntry:
# Create a SFNT directory for checksum calculation purposes # Create a SFNT directory for checksum calculation purposes
self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables, 16) self.searchRange, self.entrySelector, self.rangeShift = getSearchRange(self.numTables, 16)
@ -237,8 +242,10 @@ class SFNTWriter(object):
tables = sorted(self.tables.items()) tables = sorted(self.tables.items())
for tag, entry in tables: for tag, entry in tables:
sfntEntry = SFNTDirectoryEntry() sfntEntry = SFNTDirectoryEntry()
for item in ['tag', 'checkSum', 'offset', 'length']: sfntEntry.tag = entry.tag
setattr(sfntEntry, item, getattr(entry, item)) sfntEntry.checkSum = entry.checkSum
sfntEntry.offset = entry.origOffset
sfntEntry.length = entry.origLength
directory = directory + sfntEntry.toString() directory = directory + sfntEntry.toString()
directory_end = sfntDirectorySize + len(self.tables) * sfntDirectoryEntrySize directory_end = sfntDirectorySize + len(self.tables) * sfntDirectoryEntrySize