_h_e_a_d.py revision 8413c108d21e8cf0e9059bbfffde8d13f2616340 
1import DefaultTable
2from fontTools.misc import sstruct
3import time
4import string
5from fontTools.misc.textTools import safeEval, num2binary, binary2num
6
7
8headFormat = """
9		>	# big endian
10		tableVersion:       16.16F
11		fontRevision:       16.16F
12		checkSumAdjustment: I
13		magicNumber:        I
14		flags:              H
15		unitsPerEm:         H
16		created:            8s
17		modified:           8s
18		xMin:               h
19		yMin:               h
20		xMax:               h
21		yMax:               h
22		macStyle:           H
23		lowestRecPPEM:      H
24		fontDirectionHint:  h
25		indexToLocFormat:   h
26		glyphDataFormat:    h
27"""
28
29class table__h_e_a_d(DefaultTable.DefaultTable):
30
31	dependencies = ['maxp', 'loca']
32
33	def decompile(self, data, ttFont):
34		dummy, rest = sstruct.unpack2(headFormat, data, self)
35		if rest:
36			# this is quite illegal, but there seem to be fonts out there that do this
37			assert rest == "\0\0"
38		self.unitsPerEm = int(self.unitsPerEm)
39		self.flags = int(self.flags)
40		self.strings2dates()
41
42	def compile(self, ttFont):
43		self.modified = long(time.time() - mac_epoch_diff)
44		self.dates2strings()
45		data = sstruct.pack(headFormat, self)
46		self.strings2dates()
47		return data
48
49	def strings2dates(self):
50		self.created = bin2long(self.created)
51		self.modified = bin2long(self.modified)
52
53	def dates2strings(self):
54		self.created = long2bin(self.created)
55		self.modified = long2bin(self.modified)
56
57	def toXML(self, writer, ttFont):
58		writer.comment("Most of this table will be recalculated by the compiler")
59		writer.newline()
60		formatstring, names, fixes = sstruct.getformat(headFormat)
61		for name in names:
62			value = getattr(self, name)
63			if name in ("created", "modified"):
64				try:
65					value = time.asctime(time.gmtime(max(0, value + mac_epoch_diff)))
66				except ValueError:
67					value = time.asctime(time.gmtime(0))
68			if name in ("magicNumber", "checkSumAdjustment"):
69				if value < 0:
70					value = value + 0x100000000L
71				value = hex(value)
72				if value[-1:] == "L":
73					value = value[:-1]
74			elif name in ("macStyle", "flags"):
75				value = num2binary(value, 16)
76			writer.simpletag(name, value=value)
77			writer.newline()
78
79	def fromXML(self, (name, attrs, content), ttFont):
80		value = attrs["value"]
81		if name in ("created", "modified"):
82			value = parse_date(value) - mac_epoch_diff
83		elif name in ("macStyle", "flags"):
84			value = binary2num(value)
85		else:
86			try:
87				value = safeEval(value)
88			except OverflowError:
89				value = long(value)
90		setattr(self, name, value)
91
92	def __cmp__(self, other):
93		if type(self) != type(other) or \
94		   self.__class__ != other.__class__:
95			return cmp(id(self), id(other))
96
97		selfdict = self.__dict__.copy()
98		otherdict = other.__dict__.copy()
99		# for testing purposes, compare without the modified and checkSumAdjustment
100		# fields, since they are allowed to be different.
101		for key in ["modified", "checkSumAdjustment"]:
102			del selfdict[key]
103			del otherdict[key]
104		return cmp(selfdict, otherdict)
105
106
107def calc_mac_epoch_diff():
108	"""calculate the difference between the original Mac epoch (1904)
109	to the epoch on this machine.
110	"""
111	safe_epoch_t = (1972, 1, 1, 0, 0, 0, 0, 0, 0)
112	safe_epoch = time.mktime(safe_epoch_t) - time.timezone
113	# This assert fails in certain time zones, with certain daylight settings
114	#assert time.gmtime(safe_epoch)[:6] == safe_epoch_t[:6]
115	seconds1904to1972 = 60 * 60 * 24 * (365 * (1972-1904) + 17) # thanks, Laurence!
116	return long(safe_epoch - seconds1904to1972)
117
118mac_epoch_diff = calc_mac_epoch_diff()
119
120
121_months = ['   ', 'jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug',
122		'sep', 'oct', 'nov', 'dec']
123_weekdays = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']
124
125def parse_date(datestring):
126	datestring = string.lower(datestring)
127	weekday, month, day, tim, year = string.split(datestring)
128	weekday = _weekdays.index(weekday)
129	month = _months.index(month)
130	year = int(year)
131	day = int(day)
132	hour, minute, second = map(int, string.split(tim, ":"))
133	t = (year, month, day, hour, minute, second, weekday, 0, 0)
134	try:
135		return long(time.mktime(t) - time.timezone)
136	except OverflowError:
137		return 0L
138
139
140def bin2long(data):
141	# thanks </F>!
142	v = 0L
143	for i in map(ord, data):
144	    v = v<<8 | i
145	return v
146
147def long2bin(v, bytes=8):
148	mask = long("FF" * bytes, 16)
149	data = ""
150	while v:
151		data = chr(v & 0xff) + data
152		v = (v >> 8) & mask
153	data = (bytes - len(data)) * "\0" + data
154	assert len(data) == 8, "long too long"
155	return data
156
157