christopher@45: '''
christopher@45: Authors: Chunyang Song, Christopher Harte
christopher@45: Institution: Centre for Digital Music, Queen Mary University of London
christopher@45: '''
christopher@45: 
christopher@45: # Parse the rhythm file and return a list of Bar objects
christopher@45: #Piece = []
christopher@45: 
christopher@45: from parameter_setter import timeSignatureBase
christopher@45: from music_objects import *
christopher@45: 
christopher@45: comment_sign = '#'
christopher@45: 
christopher@45: def discard_comments(line):
christopher@45: 	if comment_sign in line:
christopher@45: 		line = line[0:line.find(comment_sign)]
christopher@45: 	return line
christopher@45: 
christopher@45: def discard_spaces(line):
christopher@45: 	line = line.replace(" ", '').replace("\t", '')
christopher@45: 	return line
christopher@45: 
christopher@45: def discard_linereturns(line):
christopher@45: 	line = line.replace("\n","").replace("\r","")
christopher@45: 	return line
christopher@45: 	
christopher@45: 
christopher@45: # def extractInfo(line):
christopher@45: # 	try:
christopher@45: # 		if '{' not in line and '}' not in line:
christopher@45: # 			raise RhythmSyntaxError(line)
christopher@45: # 		else:
christopher@45: # 			return line[line.find('{')+1 : line.find('}')]
christopher@45: # 	except RhythmSyntaxError:
christopher@45: # 		print 'Rhythmic information needs to be enclosed by "{" and "}"'
christopher@45: 
christopher@45: 
christopher@45: def read_rhythm(fileName):
christopher@45: 	fileContent = file(fileName)
christopher@45: 
christopher@45: 	barList = BarList()
christopher@45: 
christopher@45: 	tempo=None
christopher@45: 	timeSignature=None
christopher@45: 	ticksPerQuarter=None
christopher@45: 
christopher@45: 	# for each line in the file, parse the line and add any 
christopher@45: 	# new bars to the main bar list for the piece
christopher@45: 	for line in fileContent:
christopher@45: 		
christopher@45: 		# ignore the line if it's only a comment
christopher@45: 		if is_comment(line) or line=="\n":
christopher@45: 			continue
christopher@45: 
christopher@45: 		# if time signature has not yet been set then it should be the first 
christopher@45: 		# thing we find in a file after the comments at the top
christopher@45: 		if timeSignature==None:
christopher@45: 			(field, line) = get_next_field(line)
christopher@45: 			# if there is a valid field, it should be a time signature
christopher@45: 			if field!=None:
christopher@45: 				[fieldname,value] = field
christopher@45: 				if fieldname.lower()=="t":
christopher@45: 					timeSignature = TimeSignature(value)
christopher@45: 				else:
christopher@45: 					print 'Error, first field in the file should set the time signature.'
christopher@45: 
christopher@45: 		# parse the line
christopher@45: 		(newbarlist, tempo, timeSignature, ticksPerQuarter) = parse_line(line, timeSignature,  tempo, ticksPerQuarter)
christopher@45: 		
christopher@45: 		# if we found some bars in this line then add them to the overall bar list
christopher@45: 		if len(newbarlist)>0:
christopher@45: 			barList.concat(newbarlist)
christopher@45: 
christopher@45: 	return barList
christopher@45: 
christopher@45: def is_comment(line):
christopher@45: 	if discard_spaces(line)[0]==comment_sign:
christopher@45: 		return True
christopher@45: 	else:
christopher@45: 		return False
christopher@45: 
christopher@45: def parse_line(line,  timeSignature=None, tempo=None, ticksPerQuarter=None):
christopher@45: 	
christopher@45: 	#strip the line of line returns, spaces and comments
christopher@45: 	line = discard_linereturns(discard_spaces(discard_comments(line)))
christopher@45: 	
christopher@45: 	bars = BarList()
christopher@45: 
christopher@45: 	#work through each field in the line
christopher@45: 	while len(line)>0:
christopher@45: 		(field, line) = get_next_field(line)
christopher@45: 
christopher@45: 		if field!=None:
christopher@45: 			
christopher@45: 			[fieldname, value] = field
christopher@45: 			
christopher@45: 			if fieldname.lower() == "v":
christopher@45: 				#velocity sequence
christopher@45: 				bar = Bar(VelocitySequence(value),timeSignature, ticksPerQuarter, tempo)	
christopher@45: 				bars.append(bar)
christopher@45: 
christopher@45: 			elif fieldname.lower() == "y":
christopher@45: 				#note sequence	
christopher@45: 				bar = Bar(NoteSequence(value), timeSignature, ticksPerQuarter, tempo)	
christopher@45: 				bars.append(bar)
christopher@45: 
christopher@45: 			elif fieldname.lower() == "t":
christopher@45: 				#time signature
christopher@45: 				timeSignature = TimeSignature(value)
christopher@45: 			
christopher@45: 			elif fieldname.lower() == "tpq":
christopher@45: 				#ticks per quarter
christopher@45: 				ticksPerQuarter = int(value)
christopher@45: 			
christopher@45: 			elif fieldname.lower() == "qpm":
christopher@45: 				#tempo
christopher@45: 				tempo = int(value)
christopher@45: 			
christopher@45: 			else:
christopher@45: 				print 'Unrecognised field type: "' + fieldname + '"'
christopher@45: 	
christopher@45: 	return bars, tempo, timeSignature, ticksPerQuarter
christopher@45: 
christopher@45: class RhythmSyntaxError(Exception):
christopher@45: 	def __init__(self, value):
christopher@45: 		self.value = value
christopher@45: 	def __str__(self):
christopher@45: 		return repr(self.value)
christopher@45: 
christopher@45: def get_next_field(line):
christopher@45: 	index = line.find("}")
christopher@45: 	field = None
christopher@45: 	if index>=0:
christopher@45: 		fieldtext = line[:index]
christopher@45: 		line = line[index+1:]
christopher@45: 		field = fieldtext.split("{")
christopher@45: 	else:
christopher@45: 		print 'Error, incorrect syntax: "'+line+'"'
christopher@45: 		raise RhythmSyntaxError(line)
christopher@45: 
christopher@45: 	return field,line
christopher@45: 
christopher@45: 
christopher@45: 
christopher@45: 
christopher@45: