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1from fontTools.misc import sstruct
2from fontTools.misc.textTools import bytesjoin, strjoin, readHex
3from fontTools.ttLib import TTLibError
4from . import DefaultTable
5
6# Apple's documentation of 'meta':
7# https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6meta.html
8
9META_HEADER_FORMAT = """
10    > # big endian
11    version:     L
12    flags:       L
13    dataOffset:  L
14    numDataMaps: L
15"""
16
17
18DATA_MAP_FORMAT = """
19    > # big endian
20    tag:         4s
21    dataOffset:  L
22    dataLength:  L
23"""
24
25
26class table__m_e_t_a(DefaultTable.DefaultTable):
27    def __init__(self, tag=None):
28        DefaultTable.DefaultTable.__init__(self, tag)
29        self.data = {}
30
31    def decompile(self, data, ttFont):
32        headerSize = sstruct.calcsize(META_HEADER_FORMAT)
33        header = sstruct.unpack(META_HEADER_FORMAT, data[0 : headerSize])
34        if header["version"] != 1:
35            raise TTLibError("unsupported 'meta' version %d" %
36                             header["version"])
37        dataMapSize = sstruct.calcsize(DATA_MAP_FORMAT)
38        for i in range(header["numDataMaps"]):
39            dataMapOffset = headerSize + i * dataMapSize
40            dataMap = sstruct.unpack(
41                DATA_MAP_FORMAT,
42                data[dataMapOffset : dataMapOffset + dataMapSize])
43            tag = dataMap["tag"]
44            offset = dataMap["dataOffset"]
45            self.data[tag] = data[offset : offset + dataMap["dataLength"]]
46            if tag in ["dlng", "slng"]:
47                self.data[tag] = self.data[tag].decode("utf-8")
48
49    def compile(self, ttFont):
50        keys = sorted(self.data.keys())
51        headerSize = sstruct.calcsize(META_HEADER_FORMAT)
52        dataOffset = headerSize + len(keys) * sstruct.calcsize(DATA_MAP_FORMAT)
53        header = sstruct.pack(META_HEADER_FORMAT, {
54                "version": 1,
55                "flags": 0,
56                "dataOffset": dataOffset,
57                "numDataMaps": len(keys)
58        })
59        dataMaps = []
60        dataBlocks = []
61        for tag in keys:
62            if tag in ["dlng", "slng"]:
63                data = self.data[tag].encode("utf-8")
64            else:
65                data = self.data[tag]
66            dataMaps.append(sstruct.pack(DATA_MAP_FORMAT, {
67                "tag": tag,
68                "dataOffset": dataOffset,
69                "dataLength": len(data)
70            }))
71            dataBlocks.append(data)
72            dataOffset += len(data)
73        return bytesjoin([header] + dataMaps + dataBlocks)
74
75    def toXML(self, writer, ttFont):
76        for tag in sorted(self.data.keys()):
77            if tag in ["dlng", "slng"]:
78                writer.begintag("text", tag=tag)
79                writer.newline()
80                writer.write(self.data[tag])
81                writer.newline()
82                writer.endtag("text")
83                writer.newline()
84            else:
85                writer.begintag("hexdata", tag=tag)
86                writer.newline()
87                data = self.data[tag]
88                if min(data) >= 0x20 and max(data) <= 0x7E:
89                    writer.comment("ascii: " + data.decode("ascii"))
90                    writer.newline()
91                writer.dumphex(data)
92                writer.endtag("hexdata")
93                writer.newline()
94
95    def fromXML(self, name, attrs, content, ttFont):
96        if name == "hexdata":
97            self.data[attrs["tag"]] = readHex(content)
98        elif name == "text" and attrs["tag"] in ["dlng", "slng"]:
99            self.data[attrs["tag"]] = strjoin(content).strip()
100        else:
101            raise TTLibError("can't handle '%s' element" % name)
102