#!/usr/bin/ruby
# soundtest -- demonstrate the interface to the
# microphone, speaker, and buttons on the IPAQ

SNDCTL_DSP_SPEED = 0xc0045002
SNDCTL_DSP_CHANNELS = 0xc0045006
SNDCTL_DSP_SETFMT = 0xc0045005
AFMT_U8 = 8
AFMT_S16_LE = 16

# We: wait for a button press
#	record from the microphone
#	when the button is released
#	we play the recorded data

# open the touchscreen
keyFile = File.open("/dev/touchscreen/key", "r")
ch = keyFile.getc
if (ch == 1)
	puts "Button pressed"	# button on upper left side of IPAQ
	# if a button is pressed, open the microphone
	dsp = File.open("/dev/dsp", "r")
	dsp.ioctl(SNDCTL_DSP_SPEED, [16000].pack("i"))
	dsp.ioctl(SNDCTL_DSP_CHANNELS, [2].pack("i"))
	# do we need this?  only for storing as a file, not for immediate playback
	# dsp.ioctl(SOUND_PCM_READ_RATE, [0].pack("i"))
	dsp.ioctl(SNDCTL_DSP_SETFMT, [AFMT_S16_LE].pack("i"))
	samples = []
	while !Kernel.select([keyFile], nil, nil, 0) or keyFile.getc != 129
		# read from the microphone until the key is released
		samples.push dsp.read(2000)
	end
	puts "Button unpressed"
	# close the microphone for reading
	dsp.close		
	# open the speakers
	# this should be open-write-only, but not clear how to do that?
	dsp = File.open("/dev/dsp", "a")
	dsp.ioctl(SNDCTL_DSP_CHANNELS, [2].pack("i"))
	dsp.ioctl(SNDCTL_DSP_SPEED, [16000].pack("i"))
	dsp.ioctl(SNDCTL_DSP_SETFMT, [AFMT_U8].pack("i"))
	dsp.ioctl(SNDCTL_DSP_SETFMT, [AFMT_S16_LE].pack("i"))
	# and play back all the samples
	samples.each { |x| dsp.write x }
	dsp.close
end