webvtt/parsing/file-parsing/tools/parser.py - external/w3c/web-platform-tests - Git at Google

 """
 A direct translation of the webvtt file parsing algorithm.

 See https://w3c.github.io/webvtt/#file-parsing for documentation
 """
 import re
 import string

 SPACE_CHARACTERS = [' ', '\t', '\n', '\f', '\r']
 SPACE_SPLIT_PATTERN = r"[{}]*".format(''.join(SPACE_CHARACTERS))
 DIGITS = string.digits

 class DictInit:
     def __init__(self, **dict):
         self.__dict__.update(dict)

 class VTTCue(DictInit): pass
 class VTTRegion(DictInit): pass
 class Stylesheet(DictInit): pass

 class W3CParser:
     input = None
     position = None

     def collect_characters(self, condition):
         result = ""
         while self.position < len(self.input) and condition(self.input[self.position]):
             result += self.input[self.position]
             self.position += 1
         return result

     def skip_whitespace(self):
         self.collect_characters(lambda c: c in SPACE_CHARACTERS)

     def parse_percentage_string(self, input):
         'parse a percentage string'

         # 1.
         input = input

         # 2.
         if not re.match(r'^\d+(\.\d+)?%$', input):
             return None

         # 3.
         percentage = float(input[:-1])

         # 4.
         if percentage < 0 or percentage > 100:
             return None

         # 5.
         return percentage

 class VTTParser(W3CParser):
     def __init__(self, input):
         self.input = input
         self.position = 0
         self.seen_cue = False

         self.text_tracks = []
         self.stylesheets = []
         self.regions = []
         self.errors = []

     def parse(self):
         'WebVTT parser algorithm'

         # 1.
         self.input = self.input.replace('\0', '\ufffd').replace('\r\n', '\n').replace('\r', '\n')

         # 2.
         self.position = 0

         # 3.
         self.seen_cue = False

         # 4.
         if len(self.input) < 6:
             self.errors.append('input too small for webvtt')
             return

         # 5.
         if len(self.input) == 6 and self.input != 'WEBVTT':
             self.errors.append('invalid webvtt header')
             return

         # 6.
         if len(self.input) > 6:
             if not (self.input[0:6] == 'WEBVTT' and self.input[6] in ['\u0020', '\u0009', '\u000A']):
                 self.errors.append('invalid webvtt header')
                 return

         # 7.
         self.collect_characters(lambda c: c != '\n')

         # 8.
         if self.position >= len(self.input):
             return

         # 9.
         if self.input[self.position] == '\n':
             self.position += 1

         # 10.
         if self.position >= len(self.input):
             return

         # 11.
         if self.input[self.position] != '\n':
             self.collect_block(in_header = True)
         else:
             self.position += 1

         # 12.
         self.collect_characters(lambda c: c == '\n')

         # 13.
         self.regions = []

         # 14.
         while self.position < len(self.input):
             # 1.
             block = self.collect_block()

             # 2.
             if isinstance(block, VTTCue):
                 self.text_tracks.append(block)

             # 3.
             elif isinstance(block, Stylesheet):
                 self.stylesheets.append(block)

             # 4.
             elif isinstance(block, VTTRegion):
                 self.regions.append(block)

             # 5.
             self.collect_characters(lambda c: c == '\n')

         # 15.
         return

     def collect_block(self, in_header = False):
         'collect a WebVTT block'

         # 1. (done by class)

         line_count = 0                    # 2.
         previous_position = self.position # 3.
         line = ""                         # 4.
         buffer = ""                       # 5.
         seen_eof = False                  # 6.
         seen_arrow = False                # 7.
         cue = None                        # 8.
         stylesheet = None                 # 9.
         region = None                     # 10.

         # 11.
         while True:
             # 1.
             line = self.collect_characters(lambda c: c != '\n')

             # 2.
             line_count += 1

             # 3.
             if self.position >= len(self.input):
                 seen_eof = True
             else:
                 self.position += 1

             # 4.
             if '-->' in line:
                 # 1.
                 if not in_header and (line_count == 1 or line_count == 2 and not seen_arrow):
                     # 1.
                     seen_arrow = True

                     # 2.
                     previous_position = self.position

                     # 3.
                     cue = VTTCue(
                         id = buffer,
                         pause_on_exit = False,
                         region = None,
                         writing_direction = 'horizontal',
                         snap_to_lines = True,
                         line = 'auto',
                         line_alignment = 'start alignment',
                         position = 'auto',
                         position_alignment = 'auto',
                         cue_size = 100,
                         text_alignment = 'center',
                         text = '',
                     )

                     # 4.
                     if not VTTCueParser(self, line, cue).collect_cue_timings_and_settings():
                         cue = None
                     else:
                         buffer = ''
                         self.seen_cue = True # DIFFERENCE

                 else:
                     self.errors.append('invalid webvtt cue block')
                     self.position = previous_position
                     break

             # 5.
             elif line == '':
                 break

             # 6.
             else:
                 # 1.
                 if not in_header and line_count == 2:
                     # 1.
                     if not self.seen_cue and re.match(r'^STYLE\s*$', buffer):
                         stylesheet = Stylesheet(
                             location = None,
                             parent = None,
                             owner_node = None,
                             owner_rule = None,
                             media = None,
                             title = None,
                             alternate = False,
                             origin_clean = True,
                             source = None,
                         )
                         buffer = ''
                     # 2.
                     elif not self.seen_cue and re.match(r'^REGION\s*$', buffer):
                         region = VTTRegion(
                             id = '',
                             width = 100,
                             lines = 3,
                             anchor_point = (0, 100),
                             viewport_anchor_point = (0, 100),
                             scroll_value = None,
                         )
                         buffer = ''

                 # 2.
                 if buffer != '':
                     buffer += '\n'

                 # 3.
                 buffer += line

                 # 4.
                 previous_position = self.position

             # 7.
             if seen_eof:
                 break

         # 12.
         if cue is not None:
             cue.text = buffer
             return cue

         # 13.
         elif stylesheet is not None:
             stylesheet.source = buffer
             return stylesheet

         # 14.
         elif region is not None:
             self.collect_region_settings(region, buffer)
             return region

         # 15.
         return None

     def collect_region_settings(self, region, input):
         'collect WebVTT region settings'

         # 1.
         settings = re.split(SPACE_SPLIT_PATTERN, input)

         # 2.
         for setting in settings:
             # 1.
             if ':' not in setting:
                 continue

             index = setting.index(':')
             if index in [0, len(setting) - 1]:
                 continue

             # 2.
             name = setting[:index]

             # 3.
             value = setting[index + 1:]

             # 4.
             if name == "id":
                 region.id = value

             elif name == "width":
                 percentage = self.parse_percentage_string(value)
                 if percentage is not None:
                     region.width = percentage

             elif name == "lines":
                 # 1.
                 if not re.match(r'^\d+$', value):
                     continue

                 # 2.
                 number = int(value)

                 # 3.
                 region.lines = number

             elif name == "regionanchor":
                 # 1.
                 if ',' not in value:
                     continue

                 #. 2.
                 index = value.index(',')
                 anchorX = value[:index]

                 # 3.
                 anchorY = value[index + 1:]

                 # 4.
                 percentageX = self.parse_percentage_string(anchorX)
                 percentageY = self.parse_percentage_string(anchorY)
                 if None in [percentageX, percentageY]:
                     continue

                 # 5.
                 region.anchor_point = (percentageX, percentageY)

             elif name == "viewportanchor":
                 # 1.
                 if ',' not in value:
                     continue

                 #. 2.
                 index = value.index(',')
                 viewportanchorX = value[:index]

                 # 3.
                 viewportanchorY = value[index + 1:]

                 # 4.
                 percentageX = self.parse_percentage_string(viewportanchorX)
                 percentageY = self.parse_percentage_string(viewportanchorY)
                 if None in [percentageX, percentageY]:
                     continue

                 # 5.
                 region.viewport_anchor_point = (percentageX, percentageY)

             elif name == "scroll":
                 # 1.
                 if value == "up":
                     region.scroll_value = "up"

             # 5.
             continue


 class VTTCueParser(W3CParser):
     def __init__(self, parent, input, cue):
         self.parent = parent
         self.errors = self.parent.errors
         self.input = input
         self.position = 0
         self.cue = cue

     def collect_cue_timings_and_settings(self):
         'collect WebVTT cue timings and settings'

         # 1. (handled by class)

         # 2.
         self.position = 0

         # 3.
         self.skip_whitespace()

         # 4.
         timestamp = self.collect_timestamp()
         if timestamp is None:
             self.errors.append('invalid start time for VTTCue')
             return False
         self.cue.start_time = timestamp

         # 5.
         self.skip_whitespace()

         # 6.
         if self.input[self.position] != '-':
             return False
         self.position += 1

         # 7.
         if self.input[self.position] != '-':
             return False
         self.position += 1

         # 8.
         if self.input[self.position] != '>':
             return False
         self.position += 1

         # 9.
         self.skip_whitespace()

         # 10.
         timestamp = self.collect_timestamp()
         if timestamp is None:
             self.errors.append('invalid end time for VTTCue')
             return False
         self.cue.end_time = timestamp

         # 11.
         remainder = self.input[self.position:]

         # 12.
         self.parse_settings(remainder)

         # Extra
         return True

     def parse_settings(self, input):
         'parse the WebVTT cue settings'

         # 1.

         settings = re.split(SPACE_SPLIT_PATTERN, input)

         # 2.
         for setting in settings:
             # 1.
             if ':' not in setting:
                 continue

             index = setting.index(':')
             if index in [0, len(setting) - 1]:
                 continue

             # 2.
             name = setting[:index]

             # 3.
             value = setting[index + 1:]

             # 4.
             if name == 'region':
                 # 1.
                 last_regions = (region for region in reversed(self.parent.regions) if region.id == value)
                 self.cue.region = next(last_regions, None)

             elif name == 'vertical':
                 # 1. and 2.
                 if value in ['rl', 'lr']:
                     self.cue.writing_direction = value

             elif name == 'line':
                 # 1.
                 if ',' in value:
                     index = value.index(',')
                     linepos = value[:index]
                     linealign = value[index + 1:]

                 # 2.
                 else:
                     linepos = value
                     linealign = None

                 # 3.
                 if not re.search(r'\d', linepos):
                     continue

                 # 4.
                 if linepos[-1] == '%':
                     number = self.parse_percentage_string(linepos)
                     if number is None:
                         continue
                 else:
                     # 1.
                     if not re.match(r'^[-\.\d]*$', linepos):
                         continue

                     # 2.
                     if '-' in linepos[1:]:
                         continue

                     # 3.
                     if linepos.count('.') > 1:
                         continue

                     # 4.
                     if '.' in linepos:
                         if not re.search(r'\d\.\d', linepos):
                             continue

                     # 5.
                     number = float(linepos)

                 # 5.
                 if linealign == "start":
                     self.cue.line_alignment = 'start'

                 # 6.
                 elif linealign == "center":
                     self.cue.line_alignment = 'center'

                 # 7.
                 elif linealign == "end":
                     self.cue.line_alignment = 'end'

                 # 8.
                 elif linealign != None:
                     continue

                 # 9.
                 self.cue.line = number

                 # 10.
                 if linepos[-1] == '%':
                     self.cue.snap_to_lines = False
                 else:
                     self.cue.snap_to_lines = True

             elif name == 'position':
                 # 1.
                 if ',' in value:
                     index = value.index(',')
                     colpos = value[:index]
                     colalign = value[index + 1:]

                 # 2.
                 else:
                     colpos = value
                     colalign = None

                 # 3.
                 number = self.parse_percentage_string(colpos)
                 if number is None:
                     continue

                 # 4.
                 if colalign == "line-left":
                     self.cue.line_alignment = 'line-left'

                 # 5.
                 elif colalign == "center":
                     self.cue.line_alignment = 'center'

                 # 6.
                 elif colalign == "line-right":
                     self.cue.line_alignment = 'line-right'

                 # 7.
                 elif colalign != None:
                     continue

                 # 8.
                 self.cue.position = number

             elif name == 'size':
                 # 1.
                 number = self.parse_percentage_string(value)
                 if number is None:
                     continue

                 # 2.
                 self.cue.cue_size = number

             elif name == 'align':
                 # 1.
                 if value == 'start':
                     self.cue.text_alignment = 'start'

                 # 2.
                 if value == 'center':
                     self.cue.text_alignment = 'center'

                 # 3.
                 if value == 'end':
                     self.cue.text_alignment = 'end'

                 # 4.
                 if value == 'left':
                     self.cue.text_alignment = 'left'

                 # 5.
                 if value == 'right':
                     self.cue.text_alignment = 'right'

             # 5.
             continue

     def collect_timestamp(self):
         'collect a WebVTT timestamp'

         # 1. (handled by class)

         # 2.
         most_significant_units = 'minutes'

         # 3.
         if self.position >= len(self.input):
             return None

         # 4.
         if self.input[self.position] not in DIGITS:
             return None

         # 5.
         string = self.collect_characters(lambda c: c in DIGITS)

         # 6.
         value_1 = int(string)

         # 7.
         if len(string) != 2 or value_1 > 59:
             most_significant_units = 'hours'

         # 8.
         if self.position >= len(self.input) or self.input[self.position] != ':':
             return None
         self.position += 1

         # 9.
         string = self.collect_characters(lambda c: c in DIGITS)

         # 10.
         if len(string) != 2:
             return None

         # 11.
         value_2 = int(string)

         # 12.
         if most_significant_units == 'hours' or self.position < len(self.input) and self.input[self.position] == ':':
             # 1.
             if self.position >= len(self.input) or self.input[self.position] != ':':
                 return None
             self.position += 1

             # 2.
             string = self.collect_characters(lambda c: c in DIGITS)

             # 3.
             if len(string) != 2:
                 return None

             # 4.
             value_3 = int(string)
         else:
             value_3 = value_2
             value_2 = value_1
             value_1 = 0

         # 13.
         if self.position >= len(self.input) or self.input[self.position] != '.':
             return None
         self.position += 1

         # 14.
         string = self.collect_characters(lambda c: c in DIGITS)

         # 15.
         if len(string) != 3:
             return None

         # 16.
         value_4 = int(string)

         # 17.
         if value_2 >= 59 or value_3 >= 59:
             return None

         # 18.
         result = value_1 * 60 * 60 + value_2 * 60 + value_3 + value_4 / 1000

         # 19.
         return result


 def main(argv):
     files = [open(path, 'r') for path in argv[1:]]

     try:
         for file in files:
             parser = VTTParser(file.read())
             parser.parse()

             print("Results: {}".format(file))
             print("  Cues: {}".format(parser.text_tracks))
             print("  StyleSheets: {}".format(parser.stylesheets))
             print("  Regions: {}".format(parser.regions))
             print("  Errors: {}".format(parser.errors))
     finally:
         for file in files:
             file.close()

 if __name__ == '__main__':
     import sys
     main(sys.argv);
	"""
	A direct translation of the webvtt file parsing algorithm.

	See https://w3c.github.io/webvtt/#file-parsing for documentation
	"""
	import re
	import string

	SPACE_CHARACTERS = [' ', '\t', '\n', '\f', '\r']
	SPACE_SPLIT_PATTERN = r"[{}]*".format(''.join(SPACE_CHARACTERS))
	DIGITS = string.digits

	class DictInit:
	def __init__(self, **dict):
	self.__dict__.update(dict)

	class VTTCue(DictInit): pass
	class VTTRegion(DictInit): pass
	class Stylesheet(DictInit): pass

	class W3CParser:
	input = None
	position = None

	def collect_characters(self, condition):
	result = ""
	while self.position < len(self.input) and condition(self.input[self.position]):
	result += self.input[self.position]
	self.position += 1
	return result

	def skip_whitespace(self):
	self.collect_characters(lambda c: c in SPACE_CHARACTERS)

	def parse_percentage_string(self, input):
	'parse a percentage string'

	# 1.
	input = input

	# 2.
	if not re.match(r'^\d+(\.\d+)?%$', input):
	return None

	# 3.
	percentage = float(input[:-1])

	# 4.
	if percentage < 0 or percentage > 100:
	return None

	# 5.
	return percentage

	class VTTParser(W3CParser):
	def __init__(self, input):
	self.input = input
	self.position = 0
	self.seen_cue = False

	self.text_tracks = []
	self.stylesheets = []
	self.regions = []
	self.errors = []

	def parse(self):
	'WebVTT parser algorithm'

	# 1.
	self.input = self.input.replace('\0', '\ufffd').replace('\r\n', '\n').replace('\r', '\n')

	# 2.
	self.position = 0

	# 3.
	self.seen_cue = False

	# 4.
	if len(self.input) < 6:
	self.errors.append('input too small for webvtt')
	return

	# 5.
	if len(self.input) == 6 and self.input != 'WEBVTT':
	self.errors.append('invalid webvtt header')
	return

	# 6.
	if len(self.input) > 6:
	if not (self.input[0:6] == 'WEBVTT' and self.input[6] in ['\u0020', '\u0009', '\u000A']):
	self.errors.append('invalid webvtt header')
	return

	# 7.
	self.collect_characters(lambda c: c != '\n')

	# 8.
	if self.position >= len(self.input):
	return

	# 9.
	if self.input[self.position] == '\n':
	self.position += 1

	# 10.
	if self.position >= len(self.input):
	return

	# 11.
	if self.input[self.position] != '\n':
	self.collect_block(in_header = True)
	else:
	self.position += 1

	# 12.
	self.collect_characters(lambda c: c == '\n')

	# 13.
	self.regions = []

	# 14.
	while self.position < len(self.input):
	# 1.
	block = self.collect_block()

	# 2.
	if isinstance(block, VTTCue):
	self.text_tracks.append(block)

	# 3.
	elif isinstance(block, Stylesheet):
	self.stylesheets.append(block)

	# 4.
	elif isinstance(block, VTTRegion):
	self.regions.append(block)

	# 5.
	self.collect_characters(lambda c: c == '\n')

	# 15.
	return

	def collect_block(self, in_header = False):
	'collect a WebVTT block'

	# 1. (done by class)

	line_count = 0 # 2.
	previous_position = self.position # 3.
	line = "" # 4.
	buffer = "" # 5.
	seen_eof = False # 6.
	seen_arrow = False # 7.
	cue = None # 8.
	stylesheet = None # 9.
	region = None # 10.

	# 11.
	while True:
	# 1.
	line = self.collect_characters(lambda c: c != '\n')

	# 2.
	line_count += 1

	# 3.
	if self.position >= len(self.input):
	seen_eof = True
	else:
	self.position += 1

	# 4.
	if '-->' in line:
	# 1.
	if not in_header and (line_count == 1 or line_count == 2 and not seen_arrow):
	# 1.
	seen_arrow = True

	# 2.
	previous_position = self.position

	# 3.
	cue = VTTCue(
	id = buffer,
	pause_on_exit = False,
	region = None,
	writing_direction = 'horizontal',
	snap_to_lines = True,
	line = 'auto',
	line_alignment = 'start alignment',
	position = 'auto',
	position_alignment = 'auto',
	cue_size = 100,
	text_alignment = 'center',
	text = '',
	)

	# 4.
	if not VTTCueParser(self, line, cue).collect_cue_timings_and_settings():
	cue = None
	else:
	buffer = ''
	self.seen_cue = True # DIFFERENCE

	else:
	self.errors.append('invalid webvtt cue block')
	self.position = previous_position
	break

	# 5.
	elif line == '':
	break

	# 6.
	else:
	# 1.
	if not in_header and line_count == 2:
	# 1.
	if not self.seen_cue and re.match(r'^STYLE\s*$', buffer):
	stylesheet = Stylesheet(
	location = None,
	parent = None,
	owner_node = None,
	owner_rule = None,
	media = None,
	title = None,
	alternate = False,
	origin_clean = True,
	source = None,
	)
	buffer = ''
	# 2.
	elif not self.seen_cue and re.match(r'^REGION\s*$', buffer):
	region = VTTRegion(
	id = '',
	width = 100,
	lines = 3,
	anchor_point = (0, 100),
	viewport_anchor_point = (0, 100),
	scroll_value = None,
	)
	buffer = ''

	# 2.
	if buffer != '':
	buffer += '\n'

	# 3.
	buffer += line

	# 4.
	previous_position = self.position

	# 7.
	if seen_eof:
	break

	# 12.
	if cue is not None:
	cue.text = buffer
	return cue

	# 13.
	elif stylesheet is not None:
	stylesheet.source = buffer
	return stylesheet

	# 14.
	elif region is not None:
	self.collect_region_settings(region, buffer)
	return region

	# 15.
	return None

	def collect_region_settings(self, region, input):
	'collect WebVTT region settings'

	# 1.
	settings = re.split(SPACE_SPLIT_PATTERN, input)

	# 2.
	for setting in settings:
	# 1.
	if ':' not in setting:
	continue

	index = setting.index(':')
	if index in [0, len(setting) - 1]:
	continue

	# 2.
	name = setting[:index]

	# 3.
	value = setting[index + 1:]

	# 4.
	if name == "id":
	region.id = value

	elif name == "width":
	percentage = self.parse_percentage_string(value)
	if percentage is not None:
	region.width = percentage

	elif name == "lines":
	# 1.
	if not re.match(r'^\d+$', value):
	continue

	# 2.
	number = int(value)

	# 3.
	region.lines = number

	elif name == "regionanchor":
	# 1.
	if ',' not in value:
	continue

	#. 2.
	index = value.index(',')
	anchorX = value[:index]

	# 3.
	anchorY = value[index + 1:]

	# 4.
	percentageX = self.parse_percentage_string(anchorX)
	percentageY = self.parse_percentage_string(anchorY)
	if None in [percentageX, percentageY]:
	continue

	# 5.
	region.anchor_point = (percentageX, percentageY)

	elif name == "viewportanchor":
	# 1.
	if ',' not in value:
	continue

	#. 2.
	index = value.index(',')
	viewportanchorX = value[:index]

	# 3.
	viewportanchorY = value[index + 1:]

	# 4.
	percentageX = self.parse_percentage_string(viewportanchorX)
	percentageY = self.parse_percentage_string(viewportanchorY)
	if None in [percentageX, percentageY]:
	continue

	# 5.
	region.viewport_anchor_point = (percentageX, percentageY)

	elif name == "scroll":
	# 1.
	if value == "up":
	region.scroll_value = "up"

	# 5.
	continue


	class VTTCueParser(W3CParser):
	def __init__(self, parent, input, cue):
	self.parent = parent
	self.errors = self.parent.errors
	self.input = input
	self.position = 0
	self.cue = cue

	def collect_cue_timings_and_settings(self):
	'collect WebVTT cue timings and settings'

	# 1. (handled by class)

	# 2.
	self.position = 0

	# 3.
	self.skip_whitespace()

	# 4.
	timestamp = self.collect_timestamp()
	if timestamp is None:
	self.errors.append('invalid start time for VTTCue')
	return False
	self.cue.start_time = timestamp

	# 5.
	self.skip_whitespace()

	# 6.
	if self.input[self.position] != '-':
	return False
	self.position += 1

	# 7.
	if self.input[self.position] != '-':
	return False
	self.position += 1

	# 8.
	if self.input[self.position] != '>':
	return False
	self.position += 1

	# 9.
	self.skip_whitespace()

	# 10.
	timestamp = self.collect_timestamp()
	if timestamp is None:
	self.errors.append('invalid end time for VTTCue')
	return False
	self.cue.end_time = timestamp

	# 11.
	remainder = self.input[self.position:]

	# 12.
	self.parse_settings(remainder)

	# Extra
	return True

	def parse_settings(self, input):
	'parse the WebVTT cue settings'

	# 1.

	settings = re.split(SPACE_SPLIT_PATTERN, input)

	# 2.
	for setting in settings:
	# 1.
	if ':' not in setting:
	continue

	index = setting.index(':')
	if index in [0, len(setting) - 1]:
	continue

	# 2.
	name = setting[:index]

	# 3.
	value = setting[index + 1:]

	# 4.
	if name == 'region':
	# 1.
	last_regions = (region for region in reversed(self.parent.regions) if region.id == value)
	self.cue.region = next(last_regions, None)

	elif name == 'vertical':
	# 1. and 2.
	if value in ['rl', 'lr']:
	self.cue.writing_direction = value

	elif name == 'line':
	# 1.
	if ',' in value:
	index = value.index(',')
	linepos = value[:index]
	linealign = value[index + 1:]

	# 2.
	else:
	linepos = value
	linealign = None

	# 3.
	if not re.search(r'\d', linepos):
	continue

	# 4.
	if linepos[-1] == '%':
	number = self.parse_percentage_string(linepos)
	if number is None:
	continue
	else:
	# 1.
	if not re.match(r'^[-\.\d]*$', linepos):
	continue

	# 2.
	if '-' in linepos[1:]:
	continue

	# 3.
	if linepos.count('.') > 1:
	continue

	# 4.
	if '.' in linepos:
	if not re.search(r'\d\.\d', linepos):
	continue

	# 5.
	number = float(linepos)

	# 5.
	if linealign == "start":
	self.cue.line_alignment = 'start'

	# 6.
	elif linealign == "center":
	self.cue.line_alignment = 'center'

	# 7.
	elif linealign == "end":
	self.cue.line_alignment = 'end'

	# 8.
	elif linealign != None:
	continue

	# 9.
	self.cue.line = number

	# 10.
	if linepos[-1] == '%':
	self.cue.snap_to_lines = False
	else:
	self.cue.snap_to_lines = True

	elif name == 'position':
	# 1.
	if ',' in value:
	index = value.index(',')
	colpos = value[:index]
	colalign = value[index + 1:]

	# 2.
	else:
	colpos = value
	colalign = None

	# 3.
	number = self.parse_percentage_string(colpos)
	if number is None:
	continue

	# 4.
	if colalign == "line-left":
	self.cue.line_alignment = 'line-left'

	# 5.
	elif colalign == "center":
	self.cue.line_alignment = 'center'

	# 6.
	elif colalign == "line-right":
	self.cue.line_alignment = 'line-right'

	# 7.
	elif colalign != None:
	continue

	# 8.
	self.cue.position = number

	elif name == 'size':
	# 1.
	number = self.parse_percentage_string(value)
	if number is None:
	continue

	# 2.
	self.cue.cue_size = number

	elif name == 'align':
	# 1.
	if value == 'start':
	self.cue.text_alignment = 'start'

	# 2.
	if value == 'center':
	self.cue.text_alignment = 'center'

	# 3.
	if value == 'end':
	self.cue.text_alignment = 'end'

	# 4.
	if value == 'left':
	self.cue.text_alignment = 'left'

	# 5.
	if value == 'right':
	self.cue.text_alignment = 'right'

	# 5.
	continue

	def collect_timestamp(self):
	'collect a WebVTT timestamp'

	# 1. (handled by class)

	# 2.
	most_significant_units = 'minutes'

	# 3.
	if self.position >= len(self.input):
	return None

	# 4.
	if self.input[self.position] not in DIGITS:
	return None

	# 5.
	string = self.collect_characters(lambda c: c in DIGITS)

	# 6.
	value_1 = int(string)

	# 7.
	if len(string) != 2 or value_1 > 59:
	most_significant_units = 'hours'

	# 8.
	if self.position >= len(self.input) or self.input[self.position] != ':':
	return None
	self.position += 1

	# 9.
	string = self.collect_characters(lambda c: c in DIGITS)

	# 10.
	if len(string) != 2:
	return None

	# 11.
	value_2 = int(string)

	# 12.
	if most_significant_units == 'hours' or self.position < len(self.input) and self.input[self.position] == ':':
	# 1.
	if self.position >= len(self.input) or self.input[self.position] != ':':
	return None
	self.position += 1

	# 2.
	string = self.collect_characters(lambda c: c in DIGITS)

	# 3.
	if len(string) != 2:
	return None

	# 4.
	value_3 = int(string)
	else:
	value_3 = value_2
	value_2 = value_1
	value_1 = 0

	# 13.
	if self.position >= len(self.input) or self.input[self.position] != '.':
	return None
	self.position += 1

	# 14.
	string = self.collect_characters(lambda c: c in DIGITS)

	# 15.
	if len(string) != 3:
	return None

	# 16.
	value_4 = int(string)

	# 17.
	if value_2 >= 59 or value_3 >= 59:
	return None

	# 18.
	result = value_1 * 60 * 60 + value_2 * 60 + value_3 + value_4 / 1000

	# 19.
	return result


	def main(argv):
	files = [open(path, 'r') for path in argv[1:]]

	try:
	for file in files:
	parser = VTTParser(file.read())
	parser.parse()

	print("Results: {}".format(file))
	print(" Cues: {}".format(parser.text_tracks))
	print(" StyleSheets: {}".format(parser.stylesheets))
	print(" Regions: {}".format(parser.regions))
	print(" Errors: {}".format(parser.errors))
	finally:
	for file in files:
	file.close()

	if __name__ == '__main__':
	import sys
	main(sys.argv);