Mac/Demo/sound/morse.py

import sys, math, audiodev

DOT = 30
DAH = 80
OCTAVE = 2				# 1 == 441 Hz, 2 == 882 Hz, ...
SAMPWIDTH = 2
FRAMERATE = 44100
BASEFREQ = 441
QSIZE = 20000

morsetab = {
	'A': '.-',		'a': '.-',
	'B': '-...',		'b': '-...',
	'C': '-.-.',		'c': '-.-.',
	'D': '-..',		'd': '-..',
	'E': '.',		'e': '.',
	'F': '..-.',		'f': '..-.',
	'G': '--.',		'g': '--.',
	'H': '....',		'h': '....',
	'I': '..',		'i': '..',
	'J': '.---',		'j': '.---',
	'K': '-.-',		'k': '-.-',
	'L': '.-..',		'l': '.-..',
	'M': '--',		'm': '--',
	'N': '-.',		'n': '-.',
	'O': '---',		'o': '---',
	'P': '.--.',		'p': '.--.',
	'Q': '--.-',		'q': '--.-',
	'R': '.-.',		'r': '.-.',
	'S': '...',		's': '...',
	'T': '-',		't': '-',
	'U': '..-',		'u': '..-',
	'V': '...-',		'v': '...-',
	'W': '.--',		'w': '.--',
	'X': '-..-',		'x': '-..-',
	'Y': '-.--',		'y': '-.--',
	'Z': '--..',		'z': '--..',
	'0': '-----',
	'1': '.----',
	'2': '..---',
	'3': '...--',
	'4': '....-',
	'5': '.....',
	'6': '-....',
	'7': '--...',
	'8': '---..',
	'9': '----.',
	',': '--..--',
	'.': '.-.-.-',
	'?': '..--..',
	';': '-.-.-.',
	':': '---...',
	"'": '.----.',
	'-': '-....-',
	'/': '-..-.',
	'(': '-.--.-',
	')': '-.--.-',
	'_': '..--.-',
	' ': ' '
}

# If we play at 44.1 kHz (which we do), then if we produce one sine
# wave in 100 samples, we get a tone of 441 Hz.  If we produce two
# sine waves in these 100 samples, we get a tone of 882 Hz.  882 Hz
# appears to be a nice one for playing morse code.
def mkwave(octave):
	global sinewave, nowave
	sinewave = ''
	n = int(FRAMERATE / BASEFREQ)
	for i in range(n):
		val = int(math.sin(2 * math.pi * i * octave / n) * 0x7fff)
		sample = chr((val >> 8) & 255) + chr(val & 255)
		sinewave = sinewave + sample[:SAMPWIDTH]
	nowave = '\0' * (n*SAMPWIDTH)

mkwave(OCTAVE)

class BufferedAudioDev:
	def __init__(self, *args):
		import audiodev
		self._base = apply(audiodev.AudioDev, args)
		self._buffer = []
		self._filled = 0
		self._addmethods(self._base, self._base.__class__)
	def _addmethods(self, inst, cls):
		for name in cls.__dict__.keys():
			if not hasattr(self, name):
				try:
					setattr(self, name, getattr(inst, name))
				except:
					pass
		for basecls in cls.__bases__:
			self._addmethods(self, inst, basecls)
	def writeframesraw(self, frames):
		self._buffer.append(frames)
		self._filled = self._filled + len(frames)
		if self._filled >= QSIZE:
			self.flush()
	def wait(self):
		self.flush()
		self._base.wait()
	def flush(self):
		print 'flush: %d blocks, %d bytes' % (len(self._buffer), self._filled)
		if self._buffer:
			import string
			self._base.writeframes(string.joinfields(self._buffer, ''))
			self._buffer = []
			self._filled = 0

def main(args = sys.argv[1:]):
	import getopt, string
	try:
		opts, args = getopt.getopt(args, 'o:p:')
	except getopt.error:
		sys.stderr.write('Usage ' + sys.argv[0] +
				 ' [ -o outfile ] [ args ] ...\n')
		sys.exit(1)
	dev = None
	for o, a in opts:
		if o == '-o':
			import aifc
			dev = aifc.open(a, 'w')
			dev.setframerate(FRAMERATE)
			dev.setsampwidth(SAMPWIDTH)
			dev.setnchannels(1)
		if o == '-p':
			mkwave(string.atoi(a))
	if not dev:
		dev = BufferedAudioDev()
		dev.setoutrate(FRAMERATE)
		dev.setsampwidth(SAMPWIDTH)
		dev.setnchannels(1)
		dev.close = dev.stop
	if args:
		line = string.join(args)
	else:
		line = sys.stdin.readline()
	while line:
		print line
		mline = morse(line)
		print mline
		play(mline, dev)
		if hasattr(dev, 'wait'):
			dev.wait()
		if not args:
			line = sys.stdin.readline()
		else:
			line = ''
	dev.close()

# Convert a string to morse code with \001 between the characters in
# the string.
def morse(line):
	res = ''
	for c in line:
		try:
			res = res + morsetab[c] + '\001'
		except KeyError:
			pass
	return res

# Play a line of morse code.
def play(line, dev):
	for c in line:
		if c == '.':
			sine(dev, DOT)
		elif c == '-':
			sine(dev, DAH)
		else:
			pause(dev, DAH)
		pause(dev, DOT)

def sine(dev, length):
	dev.writeframesraw(sinewave*length)

def pause(dev, length):
	dev.writeframesraw(nowave*length)

if __name__ == '__main__' or sys.argv[0] == __name__:
	main()