1 files changed, 100 insertions, 0 deletions
diff --git a/lib/silfont/scripts/psfcompressgr.py b/lib/silfont/scripts/psfcompressgr.py
new file mode 100755
index 0000000..5802cce
--- /dev/null
+++ b/lib/silfont/scripts/psfcompressgr.py
@@ -0,0 +1,100 @@
+#!/usr/bin/env python
+__doc__ = 'Compress Graphite tables in a font'
+__url__ = 'http://github.com/silnrsi/pysilfont'
+__copyright__ = 'Copyright (c) 2017 SIL International (http://www.sil.org)'
+__license__ = 'Released under the MIT License (http://opensource.org/licenses/MIT)'
+__author__ = 'Martin Hosken'
+
+argspec = [
+    ('ifont',{'help': 'Input TTF'}, {'type': 'infont'}),
+    ('ofont',{'help': 'Output TTF','nargs': '?' }, {'type': 'outfont'}),
+    ('-l','--log',{'help': 'Optional log file'}, {'type': 'outfile', 'def': '_compressgr', 'optlog': True})
+]
+
+from silfont.core import execute
+from fontTools.ttLib.tables.DefaultTable import DefaultTable
+import lz4.block
+import sys, struct
+
+class lz4tuple(object) :
+    def __init__(self, start) :
+        self.start = start
+        self.literal = start
+        self.literal_len = 0
+        self.match_dist = 0
+        self.match_len = 0
+        self.end = 0
+
+    def __str__(self) :
+        return "lz4tuple(@{},{}+{},-{}+{})={}".format(self.start, self.literal, self.literal_len, self.match_dist, self.match_len, self.end)
+
+def read_literal(t, dat, start, datlen) :
+    if t == 15 and start < datlen :
+        v = ord(dat[start:start+1])
+        t += v
+        while v == 0xFF and start < datlen :
+            start += 1
+            v = ord(dat[start:start+1])
+            t += v
+        start += 1
+    return (t, start)
+
+def write_literal(num, shift) :
+    res = []
+    if num > 14 :
+        res.append(15 << shift)
+        num -= 15
+        while num > 255 :
+            res.append(255)
+            num -= 255
+        res.append(num)
+    else :
+        res.append(num << shift)
+    return bytearray(res)
+
+def parseTuple(dat, start, datlen) :
+    res = lz4tuple(start)
+    token = ord(dat[start:start+1])
+    (res.literal_len, start) = read_literal(token >> 4, dat, start+1, datlen)
+    res.literal = start
+    start += res.literal_len
+    res.end = start
+    if start > datlen - 2 : 
+        return res
+    res.match_dist = ord(dat[start:start+1]) + (ord(dat[start+1:start+2]) << 8)
+    start += 2
+    (res.match_len, start) = read_literal(token & 0xF, dat, start, datlen)
+    res.end = start
+    return res
+
+def compressGr(dat, version) :
+    if ord(dat[1:2]) < version :
+        vstr = bytes([version]) if sys.version_info.major > 2 else chr(version)
+        dat = dat[0:1] + vstr + dat[2:]
+    datc = lz4.block.compress(dat[:-4], mode='high_compression', compression=16, store_size=False)
+    # now find the final tuple
+    end = len(datc)
+    start = 0
+    curr = lz4tuple(start)
+    while curr.end < end :
+        start = curr.end
+        curr = parseTuple(datc, start, end)
+    if curr.end > end :
+        print("Sync error: {!s}".format(curr))
+    newend = write_literal(curr.literal_len + 4, 4) + datc[curr.literal:curr.literal+curr.literal_len+1] + dat[-4:]
+    lz4hdr = struct.pack(">L", (1 << 27) + (len(dat) & 0x7FFFFFF))
+    return dat[0:4] + lz4hdr + datc[0:curr.start] + newend
+
+def doit(args) :
+    infont = args.ifont
+    for tag, version in (('Silf', 5), ('Glat', 3)) :
+        dat = infont.getTableData(tag)
+        newdat = bytes(compressGr(dat, version))
+        table = DefaultTable(tag)
+        table.decompile(newdat, infont)
+        infont[tag] = table
+    return infont
+
+def cmd() : execute('FT', doit, argspec)
+if __name__ == "__main__" : cmd()
+