_h_e_a_d.py revision 14fb031125b773f0a15eb19be4f02ed8540b2db6 
1from . import DefaultTable
2from fontTools.misc import sstruct
3import time
4from fontTools.misc.textTools import safeEval, num2binary, binary2num
5
6
7headFormat = """
8		>	# big endian
9		tableVersion:       16.16F
10		fontRevision:       16.16F
11		checkSumAdjustment: I
12		magicNumber:        I
13		flags:              H
14		unitsPerEm:         H
15		created:            8s
16		modified:           8s
17		xMin:               h
18		yMin:               h
19		xMax:               h
20		yMax:               h
21		macStyle:           H
22		lowestRecPPEM:      H
23		fontDirectionHint:  h
24		indexToLocFormat:   h
25		glyphDataFormat:    h
26"""
27
28class table__h_e_a_d(DefaultTable.DefaultTable):
29
30	dependencies = ['maxp', 'loca']
31
32	def decompile(self, data, ttFont):
33		dummy, rest = sstruct.unpack2(headFormat, data, self)
34		if rest:
35			# this is quite illegal, but there seem to be fonts out there that do this
36			assert rest == "\0\0"
37		self.unitsPerEm = self.unitsPerEm
38		self.flags = self.flags
39		self.strings2dates()
40
41	def compile(self, ttFont):
42		self.modified = int(time.time() - mac_epoch_diff)
43		self.dates2strings()
44		data = sstruct.pack(headFormat, self)
45		self.strings2dates()
46		return data
47
48	def strings2dates(self):
49		self.created = bin2long(self.created)
50		self.modified = bin2long(self.modified)
51
52	def dates2strings(self):
53		self.created = long2bin(self.created)
54		self.modified = long2bin(self.modified)
55
56	def toXML(self, writer, ttFont):
57		writer.comment("Most of this table will be recalculated by the compiler")
58		writer.newline()
59		formatstring, names, fixes = sstruct.getformat(headFormat)
60		for name in names:
61			value = getattr(self, name)
62			if name in ("created", "modified"):
63				try:
64					value = time.asctime(time.gmtime(max(0, value + mac_epoch_diff)))
65				except ValueError:
66					value = time.asctime(time.gmtime(0))
67			if name in ("magicNumber", "checkSumAdjustment"):
68				if value < 0:
69					value = value + 0x100000000
70				value = hex(value)
71				if value[-1:] == "L":
72					value = value[:-1]
73			elif name in ("macStyle", "flags"):
74				value = num2binary(value, 16)
75			writer.simpletag(name, value=value)
76			writer.newline()
77
78	def fromXML(self, name, attrs, content, ttFont):
79		value = attrs["value"]
80		if name in ("created", "modified"):
81			value = parse_date(value) - mac_epoch_diff
82		elif name in ("macStyle", "flags"):
83			value = binary2num(value)
84		else:
85			value = safeEval(value)
86		setattr(self, name, value)
87
88	def __cmp__(self, other):
89		if not isinstance(self, type(other)): return cmp(type(self), type(other))
90		if self.__class__ != other.__class__: return cmp(self.__class__, other.__class__)
91
92		selfdict = self.__dict__.copy()
93		otherdict = other.__dict__.copy()
94		# for testing purposes, compare without the modified and checkSumAdjustment
95		# fields, since they are allowed to be different.
96		for key in ["modified", "checkSumAdjustment"]:
97			del selfdict[key]
98			del otherdict[key]
99		return cmp(selfdict, otherdict)
100
101
102def calc_mac_epoch_diff():
103	"""calculate the difference between the original Mac epoch (1904)
104	to the epoch on this machine.
105	"""
106	safe_epoch_t = (1972, 1, 1, 0, 0, 0, 0, 0, 0)
107	safe_epoch = time.mktime(safe_epoch_t) - time.timezone
108	# This assert fails in certain time zones, with certain daylight settings
109	#assert time.gmtime(safe_epoch)[:6] == safe_epoch_t[:6]
110	seconds1904to1972 = 60 * 60 * 24 * (365 * (1972-1904) + 17) # thanks, Laurence!
111	return int(safe_epoch - seconds1904to1972)
112
113mac_epoch_diff = calc_mac_epoch_diff()
114
115
116_months = ['   ', 'jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug',
117		'sep', 'oct', 'nov', 'dec']
118_weekdays = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun']
119
120def parse_date(datestring):
121	datestring = datestring.lower()
122	weekday, month, day, tim, year = datestring.split()
123	weekday = _weekdays.index(weekday)
124	month = _months.index(month)
125	year = int(year)
126	day = int(day)
127	hour, minute, second = [int(item) for item in tim.split(":")]
128	t = (year, month, day, hour, minute, second, weekday, 0, 0)
129	return int(time.mktime(t) - time.timezone)
130
131
132def bin2long(data):
133	# thanks </F>!
134	v = 0
135	for i in map(ord, data):
136	    v = v<<8 | i
137	return v
138
139def long2bin(v, bytes=8):
140	mask = int("FF" * bytes, 16)
141	data = ""
142	while v:
143		data = chr(v & 0xff) + data
144		v = (v >> 8) & mask
145	data = (bytes - len(data)) * "\0" + data
146	assert len(data) == 8, "long too long"
147	return data
148
149