Lib/fontTools/misc/psLib.py

from __future__ import print_function, division, absolute_import
from fontTools.misc.py23 import *
from fontTools.misc import eexec
from .psOperators import *
import re
try:
	from collections.abc import Callable
except ImportError:  # python < 3.3
	from collections import Callable
from string import whitespace
import logging


log = logging.getLogger(__name__)

ps_special = b'()<>[]{}%'	# / is one too, but we take care of that one differently

skipwhiteRE = re.compile(bytesjoin([b"[", whitespace, b"]*"]))
endofthingPat = bytesjoin([b"[^][(){}<>/%", whitespace, b"]*"])
endofthingRE = re.compile(endofthingPat)
commentRE = re.compile(b"%[^\n\r]*")

# XXX This not entirely correct as it doesn't allow *nested* embedded parens:
stringPat = br"""
	\(
		(
			(
				[^()]*   \   [()]
			)
			|
			(
				[^()]*  \(   [^()]*  \)
			)
		)*
		[^()]*
	\)
"""
stringPat = b"".join(stringPat.split())
stringRE = re.compile(stringPat)

hexstringRE = re.compile(bytesjoin([b"<[", whitespace, b"0-9A-Fa-f]*>"]))

class PSTokenError(Exception): pass
class PSError(Exception): pass


class PSTokenizer(object):

	def __init__(self, buf=b'', encoding="ascii"):
		# Force self.buf to be a byte string
		buf = tobytes(buf)
		self.buf = buf
		self.len = len(buf)
		self.pos = 0
		self.closed = False
		self.encoding = encoding

	def read(self, n=-1):
		"""Read at most 'n' bytes from the buffer, or less if the read
		hits EOF before obtaining 'n' bytes.
		If 'n' is negative or omitted, read all data until EOF is reached.
		"""
		if self.closed:
			raise ValueError("I/O operation on closed file")
		if n is None or n < 0:
			newpos = self.len
		else:
			newpos = min(self.pos+n, self.len)
		r = self.buf[self.pos:newpos]
		self.pos = newpos
		return r

	def close(self):
		if not self.closed:
			self.closed = True
			del self.buf, self.pos

	def getnexttoken(self,
			# localize some stuff, for performance
			len=len,
			ps_special=ps_special,
			stringmatch=stringRE.match,
			hexstringmatch=hexstringRE.match,
			commentmatch=commentRE.match,
			endmatch=endofthingRE.match):

		self.skipwhite()
		if self.pos >= self.len:
			return None, None
		pos = self.pos
		buf = self.buf
		char = bytechr(byteord(buf[pos]))
		if char in ps_special:
			if char in b'{}[]':
				tokentype = 'do_special'
				token = char
			elif char == b'%':
				tokentype = 'do_comment'
				_, nextpos = commentmatch(buf, pos).span()
				token = buf[pos:nextpos]
			elif char == b'(':
				tokentype = 'do_string'
				m = stringmatch(buf, pos)
				if m is None:
					raise PSTokenError('bad string at character %d' % pos)
				_, nextpos = m.span()
				token = buf[pos:nextpos]
			elif char == b'<':
				tokentype = 'do_hexstring'
				m = hexstringmatch(buf, pos)
				if m is None:
					raise PSTokenError('bad hexstring at character %d' % pos)
				_, nextpos = m.span()
				token = buf[pos:nextpos]
			else:
				raise PSTokenError('bad token at character %d' % pos)
		else:
			if char == b'/':
				tokentype = 'do_literal'
				m = endmatch(buf, pos+1)
			else:
				tokentype = ''
				m = endmatch(buf, pos)
			if m is None:
				raise PSTokenError('bad token at character %d' % pos)
			_, nextpos = m.span()
			token = buf[pos:nextpos]
		self.pos = pos + len(token)
		token = tostr(token, encoding=self.encoding)
		return tokentype, token

	def skipwhite(self, whitematch=skipwhiteRE.match):
		_, nextpos = whitematch(self.buf, self.pos).span()
		self.pos = nextpos

	def starteexec(self):
		self.pos = self.pos + 1
		self.dirtybuf = self.buf[self.pos:]
		self.buf, R = eexec.decrypt(self.dirtybuf, 55665)
		self.len = len(self.buf)
		self.pos = 4

	def stopeexec(self):
		if not hasattr(self, 'dirtybuf'):
			return
		self.buf = self.dirtybuf
		del self.dirtybuf


class PSInterpreter(PSOperators):

	def __init__(self, encoding="ascii"):
		systemdict = {}
		userdict = {}
		self.encoding = encoding
		self.dictstack = [systemdict, userdict]
		self.stack = []
		self.proclevel = 0
		self.procmark = ps_procmark()
		self.fillsystemdict()

	def fillsystemdict(self):
		systemdict = self.dictstack[0]
		systemdict['['] = systemdict['mark'] = self.mark = ps_mark()
		systemdict[']'] = ps_operator(']', self.do_makearray)
		systemdict['true'] = ps_boolean(1)
		systemdict['false'] = ps_boolean(0)
		systemdict['StandardEncoding'] = ps_array(ps_StandardEncoding)
		systemdict['FontDirectory'] = ps_dict({})
		self.suckoperators(systemdict, self.__class__)

	def suckoperators(self, systemdict, klass):
		for name in dir(klass):
			attr = getattr(self, name)
			if isinstance(attr, Callable) and name[:3] == 'ps_':
				name = name[3:]
				systemdict[name] = ps_operator(name, attr)
		for baseclass in klass.__bases__:
			self.suckoperators(systemdict, baseclass)

	def interpret(self, data, getattr=getattr):
		tokenizer = self.tokenizer = PSTokenizer(data, self.encoding)
		getnexttoken = tokenizer.getnexttoken
		do_token = self.do_token
		handle_object = self.handle_object
		try:
			while 1:
				tokentype, token = getnexttoken()
				if not token:
					break
				if tokentype:
					handler = getattr(self, tokentype)
					object = handler(token)
				else:
					object = do_token(token)
				if object is not None:
					handle_object(object)
			tokenizer.close()
			self.tokenizer = None
		except:
			if self.tokenizer is not None:
				log.debug(
					'ps error:\n'
					'- - - - - - -\n'
					'%s\n'
					'>>>\n'
					'%s\n'
					'- - - - - - -',
					self.tokenizer.buf[self.tokenizer.pos-50:self.tokenizer.pos],
					self.tokenizer.buf[self.tokenizer.pos:self.tokenizer.pos+50])
			raise

	def handle_object(self, object):
		if not (self.proclevel or object.literal or object.type == 'proceduretype'):
			if object.type != 'operatortype':
				object = self.resolve_name(object.value)
			if object.literal:
				self.push(object)
			else:
				if object.type == 'proceduretype':
					self.call_procedure(object)
				else:
					object.function()
		else:
			self.push(object)

	def call_procedure(self, proc):
		handle_object = self.handle_object
		for item in proc.value:
			handle_object(item)

	def resolve_name(self, name):
		dictstack = self.dictstack
		for i in range(len(dictstack)-1, -1, -1):
			if name in dictstack[i]:
				return dictstack[i][name]
		raise PSError('name error: ' + str(name))

	def do_token(self, token,
				int=int,
				float=float,
				ps_name=ps_name,
				ps_integer=ps_integer,
				ps_real=ps_real):
		try:
			num = int(token)
		except (ValueError, OverflowError):
			try:
				num = float(token)
			except (ValueError, OverflowError):
				if '#' in token:
					hashpos = token.find('#')
					try:
						base = int(token[:hashpos])
						num = int(token[hashpos+1:], base)
					except (ValueError, OverflowError):
						return ps_name(token)
					else:
						return ps_integer(num)
				else:
					return ps_name(token)
			else:
				return ps_real(num)
		else:
			return ps_integer(num)

	def do_comment(self, token):
		pass

	def do_literal(self, token):
		return ps_literal(token[1:])

	def do_string(self, token):
		return ps_string(token[1:-1])

	def do_hexstring(self, token):
		hexStr = "".join(token[1:-1].split())
		if len(hexStr) % 2:
			hexStr = hexStr + '0'
		cleanstr = []
		for i in range(0, len(hexStr), 2):
			cleanstr.append(chr(int(hexStr[i:i+2], 16)))
		cleanstr = "".join(cleanstr)
		return ps_string(cleanstr)

	def do_special(self, token):
		if token == '{':
			self.proclevel = self.proclevel + 1
			return self.procmark
		elif token == '}':
			proc = []
			while 1:
				topobject = self.pop()
				if topobject == self.procmark:
					break
				proc.append(topobject)
			self.proclevel = self.proclevel - 1
			proc.reverse()
			return ps_procedure(proc)
		elif token == '[':
			return self.mark
		elif token == ']':
			return ps_name(']')
		else:
			raise PSTokenError('huh?')

	def push(self, object):
		self.stack.append(object)

	def pop(self, *types):
		stack = self.stack
		if not stack:
			raise PSError('stack underflow')
		object = stack[-1]
		if types:
			if object.type not in types:
				raise PSError('typecheck, expected %s, found %s' % (repr(types), object.type))
		del stack[-1]
		return object

	def do_makearray(self):
		array = []
		while 1:
			topobject = self.pop()
			if topobject == self.mark:
				break
			array.append(topobject)
		array.reverse()
		self.push(ps_array(array))

	def close(self):
		"""Remove circular references."""
		del self.stack
		del self.dictstack


def unpack_item(item):
	tp = type(item.value)
	if tp == dict:
		newitem = {}
		for key, value in item.value.items():
			newitem[key] = unpack_item(value)
	elif tp == list:
		newitem = [None] * len(item.value)
		for i in range(len(item.value)):
			newitem[i] = unpack_item(item.value[i])
		if item.type == 'proceduretype':
			newitem = tuple(newitem)
	else:
		newitem = item.value
	return newitem

def suckfont(data, encoding="ascii"):
	m = re.search(br"/FontName\s+/([^ \t\n\r]+)\s+def", data)
	if m:
		fontName = m.group(1)
	else:
		fontName = None
	interpreter = PSInterpreter(encoding=encoding)
	interpreter.interpret(b"/Helvetica 4 dict dup /Encoding StandardEncoding put definefont pop")
	interpreter.interpret(data)
	fontdir = interpreter.dictstack[0]['FontDirectory'].value
	if fontName in fontdir:
		rawfont = fontdir[fontName]
	else:
		# fall back, in case fontName wasn't found
		fontNames = list(fontdir.keys())
		if len(fontNames) > 1:
			fontNames.remove("Helvetica")
		fontNames.sort()
		rawfont = fontdir[fontNames[0]]
	interpreter.close()
	return unpack_item(rawfont)