algo/al/audio.go

// Audio extension
package al

/*
#cgo pkg-config: allegro_audio-5
#cgo CFLAGS: -I/usr/local/include -DALLEGRO_UNSTABLE
#cgo linux LDFLAGS: -lc_nonshared
#include <stdlib.h>
#include <allegro5/allegro.h>
#include <allegro5/allegro_audio.h>
#include "helpers.h"
*/
import "C"
import "runtime"
import "unsafe"

// User event type emitted when a stream fragment is ready to be
// refilled with more audio data.
const (
    EVENT_AUDIO_STREAM_FRAGMENT   = C.ALLEGRO_EVENT_AUDIO_STREAM_FRAGMENT
    EVENT_AUDIO_STREAM_FINISHED   = C.ALLEGRO_EVENT_AUDIO_STREAM_FINISHED
    EVENT_AUDIO_RECORDER_FRAGMENT = C.ALLEGRO_EVENT_AUDIO_RECORDER_FRAGMENT
)

// Converts wrapper Event pointer to C Allegro audio recorder event
func (self *Event) AUDIO_RECORDER_EVENT() *C.ALLEGRO_AUDIO_RECORDER_EVENT {
    return (*C.ALLEGRO_AUDIO_RECORDER_EVENT)(self.toPointer())
}

type AudioRecorderEvent C.ALLEGRO_AUDIO_RECORDER_EVENT

type AudioDepth int

// Converts an AudioDepth to an ALLEGRO_AUDIO_DEPTH
func (self AudioDepth) toC() C.ALLEGRO_AUDIO_DEPTH {
    return C.ALLEGRO_AUDIO_DEPTH(self)
}

const (
    AUDIO_DEPTH_INT8     AudioDepth = C.ALLEGRO_AUDIO_DEPTH_INT8
    AUDIO_DEPTH_INT16    AudioDepth = C.ALLEGRO_AUDIO_DEPTH_INT16
    AUDIO_DEPTH_INT24    AudioDepth = C.ALLEGRO_AUDIO_DEPTH_INT24
    AUDIO_DEPTH_UINT8    AudioDepth = C.ALLEGRO_AUDIO_DEPTH_UINT8
    AUDIO_DEPTH_UINT16   AudioDepth = C.ALLEGRO_AUDIO_DEPTH_UINT16
    AUDIO_DEPTH_UINT24   AudioDepth = C.ALLEGRO_AUDIO_DEPTH_UINT24
    AUDIO_DEPTH_FLOAT32  AudioDepth = C.ALLEGRO_AUDIO_DEPTH_FLOAT32
    AUDIO_DEPTH_UNSIGNED AudioDepth = C.ALLEGRO_AUDIO_DEPTH_UNSIGNED
)

/*
   Speaker configuration (mono, stereo, 2.1, 3, etc). With regards to
   * behavior, most of this code makes no distinction between, say, 4.1 and
   * 5 speaker setups.. they both have 5 "channels". However, users would
   * like the distinction, and later when the higher-level stuff is added,
   * the differences will become more important. (v>>4)+(v&0xF) should yield
   * the total channel count.
*/
type ChannelConf int

// Converts a ChannelConf to a C.ALLEGRO_CHANNEL_CONF
func (self ChannelConf) toC() C.ALLEGRO_CHANNEL_CONF {
    return (C.ALLEGRO_CHANNEL_CONF)(self)
}

const (
    CHANNEL_CONF_1   ChannelConf = C.ALLEGRO_CHANNEL_CONF_1
    CHANNEL_CONF_2   ChannelConf = C.ALLEGRO_CHANNEL_CONF_2
    CHANNEL_CONF_3   ChannelConf = C.ALLEGRO_CHANNEL_CONF_3
    CHANNEL_CONF_4   ChannelConf = C.ALLEGRO_CHANNEL_CONF_4
    CHANNEL_CONF_5_1 ChannelConf = C.ALLEGRO_CHANNEL_CONF_5_1
    CHANNEL_CONF_6_1 ChannelConf = C.ALLEGRO_CHANNEL_CONF_6_1
    CHANNEL_CONF_7_1 ChannelConf = C.ALLEGRO_CHANNEL_CONF_7_1
    MAX_CHANNELS     ChannelConf = C.ALLEGRO_MAX_CHANNELS
)

type PlayMode int

// Converts a PlayMode to a C.ALLEGRO_PLAYMODE
func (self PlayMode) toC() C.ALLEGRO_PLAYMODE {
    return (C.ALLEGRO_PLAYMODE)(self)
}

const (
    PLAYMODE_ONCE  PlayMode = C.ALLEGRO_PLAYMODE_ONCE
    PLAYMODE_LOOP  PlayMode = C.ALLEGRO_PLAYMODE_LOOP
    PLAYMODE_BIDIR PlayMode = C.ALLEGRO_PLAYMODE_BIDIR
)

type MixerQuality int

// Converts a MixerQuaklity to a C.ALLEGRO_MIXER_QUALITY
func (self MixerQuality) toC() C.ALLEGRO_MIXER_QUALITY {
    return (C.ALLEGRO_MIXER_QUALITY)(self)
}

const (
    MIXER_QUALITY_POINT  MixerQuality = C.ALLEGRO_MIXER_QUALITY_POINT
    MIXER_QUALITY_LINEAR MixerQuality = C.ALLEGRO_MIXER_QUALITY_LINEAR
    MIXER_QUALITY_CUBIC  MixerQuality = C.ALLEGRO_MIXER_QUALITY_CUBIC
)

const AUDIO_PAN_NONE = -1000.0

type AudioEventType int

type Sample struct {
    handle *C.ALLEGRO_SAMPLE
}

type SampleId C.ALLEGRO_SAMPLE_ID

func (self *SampleId) toC() *C.ALLEGRO_SAMPLE_ID {
    return (*C.ALLEGRO_SAMPLE_ID)(self)
}

type SampleInstance struct {
    handle *C.ALLEGRO_SAMPLE_INSTANCE
}

type AudioStream struct {
    handle *C.ALLEGRO_AUDIO_STREAM
}

type Mixer struct {
    handle *C.ALLEGRO_MIXER
}

type Voice struct {
    handle *C.ALLEGRO_VOICE
}

type AudioRecorder struct {
    handle *C.ALLEGRO_AUDIO_RECORDER
}

func (self *Sample) toC() *C.ALLEGRO_SAMPLE {
    return (*C.ALLEGRO_SAMPLE)(self.handle)
}

// Destroys the sample.
func (self *Sample) Destroy() {
    if self.handle != nil {
        C.al_destroy_sample(self.toC())
    }
    self.handle = nil
}

// Sets up a finalizer for this Sample that calls Destroy() and return self
func (self *Sample) SetDestroyFinalizer() *Sample {
    if self != nil {
        runtime.SetFinalizer(self, func(me *Sample) { me.Destroy() })
    }
    return self
}

func wrapSampleRaw(sample *C.ALLEGRO_SAMPLE) *Sample {
    if sample == nil {
        return nil
    }
    return &Sample{sample}
}

func wrapSample(sample *C.ALLEGRO_SAMPLE) *Sample {
    self := wrapSampleRaw(sample)
    if self != nil {
        runtime.SetFinalizer(self, func(me *Sample) { me.Destroy() })
    }
    return self
}

func createSample(data []byte, samples uint, freq uint, depth AudioDepth, chan_conf ChannelConf) *C.ALLEGRO_SAMPLE {
    // don't let allegro free the data, it's owned by Go.
    // XXX: copy data here in stead of using the go data???
    return C.al_create_sample(unsafe.Pointer(&data[0]), C.uint(samples),
        C.uint(freq), depth.toC(), chan_conf.toC(), b2cb(false))
}

// Creates a Sample with a Destroy finalizer set. BEWARE! data must be big enough fort he params
// or this will crash spectacularly. Also, make sure that data doesn't get collected by the GC, or 
// trouble will arise. 
func CreateSample(data []byte, samples uint, freq uint, depth AudioDepth, chan_conf ChannelConf) *Sample {
    return wrapSample(createSample(data, samples, freq, depth, chan_conf))
}

// Returns the frequency of the sample
func (self *Sample) Frequency() uint {
    return uint(C.al_get_sample_frequency(self.handle))
}

// Returns the length of the sample
func (self *Sample) Length() uint {
    return uint(C.al_get_sample_length(self.handle))
}

// Returns the depth of the sample 
func (self *Sample) Depth() uint {
    return uint(C.al_get_sample_depth(self.handle))
}

// returns the amount of channels the sample has
func (self *Sample) Channels() uint {
    return uint(C.al_get_sample_channels(self.handle))
}

// Returns the raw data pointer of the sample data. 
func (self *Sample) DataRaw() unsafe.Pointer {
    return (C.al_get_sample_data(self.handle))
}

// Returns the frequency of the sample instance
func (self *SampleInstance) Frequency() uint {
    return uint(C.al_get_sample_instance_frequency(self.handle))
}

// Returns the length of the sample instance
func (self *SampleInstance) Length() uint {
    return uint(C.al_get_sample_instance_length(self.handle))
}

// Returns the position of the sample instance
func (self *SampleInstance) Position() uint {
    return uint(C.al_get_sample_instance_position(self.handle))
}

// Returns the of the sample instance
func (self *SampleInstance) Speed() float32 {
    return float32(C.al_get_sample_instance_speed(self.handle))
}

// Returns the of the sample instance
func (self *SampleInstance) Gain() float32 {
    return float32(C.al_get_sample_instance_gain(self.handle))
}

// Returns the of the sample instance
func (self *SampleInstance) Pan() float32 {
    return float32(C.al_get_sample_instance_pan(self.handle))
}

// Returns the of the sample instance
func (self *SampleInstance) Time() float32 {
    return float32(C.al_get_sample_instance_time(self.handle))
}

// Returns the depth of the sample instance
func (self *SampleInstance) Depth() AudioDepth {
    return AudioDepth(C.al_get_sample_instance_depth(self.handle))
}

// Returns the channel configuration of the sample instance
func (self *SampleInstance) Channels() ChannelConf {
    return ChannelConf(C.al_get_sample_instance_channels(self.handle))
}

// Returns the play mode of the sample instance
func (self *SampleInstance) Playmode() PlayMode {
    return PlayMode(C.al_get_sample_instance_playmode(self.handle))
}

// Returns wheter or not the sample instance is playing
func (self *SampleInstance) Playing() bool {
    return cb2b(C.al_get_sample_instance_playing(self.handle))
}

// Returns wheter or not the sample instance is attached
func (self *SampleInstance) Attached() bool {
    return cb2b(C.al_get_sample_instance_attached(self.handle))
}

// Sets the position of the sample instance.
func (self *SampleInstance) SetPosition(val uint) bool {
    return cb2b(C.al_set_sample_instance_position(self.handle, C.uint(val)))
}

// Sets the length of the sample instance.
func (self *SampleInstance) SetLength(val uint) bool {
    return cb2b(C.al_set_sample_instance_length(self.handle, C.uint(val)))
}

// Sets the speed of the sample instance.
func (self *SampleInstance) SetSpeed(val float32) bool {
    return cb2b(C.al_set_sample_instance_speed(self.handle, C.float(val)))
}

// Sets the gain of the sample instance.
func (self *SampleInstance) SetGain(val float32) bool {
    return cb2b(C.al_set_sample_instance_gain(self.handle, C.float(val)))
}

// Sets the pan of the sample instance.
func (self *SampleInstance) SetPan(val float32) bool {
    return cb2b(C.al_set_sample_instance_pan(self.handle, C.float(val)))
}

// Sets the play mode of the sample instance.
func (self *SampleInstance) SetPlaymode(val PlayMode) bool {
    return cb2b(C.al_set_sample_instance_playmode(self.handle, val.toC()))
}

// Sets the play status of the sample instance.
func (self *SampleInstance) SetPlaying(val bool) bool {
    return cb2b(C.al_set_sample_instance_playing(self.handle, b2cb(val)))
}

// Detaches the sample instance from it's player
func (self *SampleInstance) Detach() bool {
    return cb2b(C.al_detach_sample_instance(self.handle))
}

// Sets the sample data to use for the sample instance
func (self *SampleInstance) SetSample(val *Sample) bool {
    return cb2b(C.al_set_sample(self.handle, val.handle))
}

// Gets the RAW sample data that was linked to the sample instance
func (self *SampleInstance) SampleRaw() *Sample {
    return wrapSampleRaw(C.al_get_sample(self.handle))
}

// Plays the sample instance 
func (self *SampleInstance) Play() bool {
    return cb2b(C.al_play_sample_instance(self.handle))
}

// Stops the sample instannce playback
func (self *SampleInstance) Stop() bool {
    return cb2b(C.al_stop_sample_instance(self.handle))
}

func (self *AudioStream) toC() *C.ALLEGRO_AUDIO_STREAM {
    return (*C.ALLEGRO_AUDIO_STREAM)(self.handle)
}

// Destroys the audio stream.
func (self *AudioStream) Destroy() {
    if self.handle != nil {
        C.al_destroy_audio_stream(self.toC())
    }
    self.handle = nil
}

// Sets up a finalizer for this AudioStream that calls Destroy() and return self
func (self *AudioStream) SetDestroyFinalizer() *AudioStream {
    if self != nil {
        runtime.SetFinalizer(self, func(me *AudioStream) { me.Destroy() })
    }
    return self
}

func wrapAudioStreamRaw(data *C.ALLEGRO_AUDIO_STREAM) *AudioStream {
    if data == nil {
        return nil
    }
    return &AudioStream{data}
}

func wrapAudioStream(data *C.ALLEGRO_AUDIO_STREAM) *AudioStream {
    self := wrapAudioStreamRaw(data)
    return self.SetDestroyFinalizer()
}

// Creates an audio stream, with finalizer installed.
func CreateAudioStream(bufc, samples, freq uint, depth AudioDepth, chan_conf ChannelConf) *AudioStream {
    return wrapAudioStream(C.al_create_audio_stream(C.size_t(bufc), C.uint(samples),
        C.uint(freq), depth.toC(), chan_conf.toC()))
}

// Creates an audio stream, with NO finalizer installed.
func CreateAudioStreamRaw(bufc, samples, freq uint, depth AudioDepth, chan_conf ChannelConf) *AudioStream {
    return wrapAudioStreamRaw(C.al_create_audio_stream(C.size_t(bufc), C.uint(samples),
        C.uint(freq), depth.toC(), chan_conf.toC()))
}

// Drains all data from an audio stream
func (self *AudioStream) Drain() {
    C.al_drain_audio_stream(self.handle)
}

// Returns the frequency of the audio stream
func (self *AudioStream) Frequency() uint {
    return uint(C.al_get_audio_stream_frequency(self.handle))
}

// Returns the length of the audio stream
func (self *AudioStream) Length() uint {
    return uint(C.al_get_audio_stream_length(self.handle))
}

// Returns the speed of the audio stream
func (self *AudioStream) Speed() float32 {
    return float32(C.al_get_audio_stream_speed(self.handle))
}

// Returns the amount of fragments of the audio stream
func (self *AudioStream) Fragments() float32 {
    return float32(C.al_get_audio_stream_fragments(self.handle))
}

// Returns the amount of available fragments of the audio stream
func (self *AudioStream) AvailableFragments() float32 {
    return float32(C.al_get_available_audio_stream_fragments(self.handle))
}

// Returns the gain of the audio stream
func (self *AudioStream) Gain() float32 {
    return float32(C.al_get_audio_stream_gain(self.handle))
}

// Returns the pan of the audio stream
func (self *AudioStream) Pan() float32 {
    return float32(C.al_get_audio_stream_pan(self.handle))
}

// Returns the depth of the audio stream
func (self *AudioStream) Depth() AudioDepth {
    return AudioDepth(C.al_get_audio_stream_depth(self.handle))
}

// Returns the channel configuration of the audio stream
func (self *AudioStream) Channels() ChannelConf {
    return ChannelConf(C.al_get_audio_stream_channels(self.handle))
}

// Returns the play mode of the audio stream
func (self *AudioStream) Playmode() PlayMode {
    return PlayMode(C.al_get_audio_stream_playmode(self.handle))
}

// Returns wheter or not the audio stream is playing
func (self *AudioStream) Playing() bool {
    return cb2b(C.al_get_audio_stream_playing(self.handle))
}

// Returns wheter or not the audio stream is attached
func (self *AudioStream) Attached() bool {
    return cb2b(C.al_get_audio_stream_attached(self.handle))
}

// Returns an unsafe pointer to the audio stream's fragment
func (self *AudioStream) Fragment() unsafe.Pointer {
    return C.al_get_audio_stream_fragment(self.handle)
}

// Sets the speed of the audio stream.
func (self *AudioStream) SetSpeed(val float32) bool {
    return cb2b(C.al_set_audio_stream_speed(self.handle, C.float(val)))
}

// Sets the gain of the audio stream.
func (self *AudioStream) SetGain(val float32) bool {
    return cb2b(C.al_set_audio_stream_gain(self.handle, C.float(val)))
}

// Sets the pan of the audio stream.
func (self *AudioStream) SetPan(val float32) bool {
    return cb2b(C.al_set_audio_stream_pan(self.handle, C.float(val)))
}

// Sets the play mode of the audio stream.
func (self *AudioStream) SetPlaymode(val PlayMode) bool {
    return cb2b(C.al_set_audio_stream_playmode(self.handle, val.toC()))
}

// Sets the play status of the audio stream.
func (self *AudioStream) SetPlaying(val bool) bool {
    return cb2b(C.al_set_audio_stream_playing(self.handle, b2cb(val)))
}

// Detaches the audio stream from it's player
func (self *AudioStream) Detach() bool {
    return cb2b(C.al_detach_audio_stream(self.handle))
}

// Sets an unsafe pointer as the the audio stream's fragment
func (self *AudioStream) SetFragment(ptr unsafe.Pointer) bool {
    return cb2b(C.al_set_audio_stream_fragment(self.handle, ptr))
}

// Rewinds the audio stream
func (self *AudioStream) Rewind() bool {
    return cb2b(C.al_rewind_audio_stream(self.handle))
}

// Seeks to a position in the audio stream, expressed in seconds.
func (self *AudioStream) SeekSeconds(secs float64) bool {
    return cb2b(C.al_seek_audio_stream_secs(self.handle, C.double(secs)))
}

// Gets the position in the audio stream, expressed in seconds.
func (self *AudioStream) PositionSeconds() (secs float64) {
    return float64(C.al_get_audio_stream_position_secs(self.handle))
}

// Gets the length of the audio stream, expressed in seconds.
func (self *AudioStream) LengthSeconds() (secs float64) {
    return float64(C.al_get_audio_stream_length_secs(self.handle))
}

// Sets up a loop in the audio stream, expressed in seconds.
func (self *AudioStream) LoopSeconds(start, end float64) bool {
    return cb2b(C.al_set_audio_stream_loop_secs(self.handle, C.double(start), C.double(end)))
}

// Returns the event source to use to listen to events on the audio stream.
func (self *AudioStream) Eventsource() *EventSource {
    return wrapEventSourceRaw(C.al_get_audio_stream_event_source(self.handle))
}

// Converts a mixer to it's underlying C pointer
func (self *Mixer) toC() *C.ALLEGRO_MIXER {
    return (*C.ALLEGRO_MIXER)(self.handle)
}

// Destroys the mixer.
func (self *Mixer) Destroy() {
    if self.handle != nil {
        C.al_destroy_mixer(self.toC())
    }
    self.handle = nil
}

// Sets up a finalizer for this Mixer that calls Destroy() and return self
func (self *Mixer) SetDestroyFinalizer() *Mixer {
    if self != nil {
        runtime.SetFinalizer(self, func(me *Mixer) { me.Destroy() })
    }
    return self
}

// Wraps a C mixer into a go mixer
func wrapMixerRaw(data *C.ALLEGRO_MIXER) *Mixer {
    if data == nil {
        return nil
    }
    return &Mixer{data}
}

// Wraps a C mixer into a go mixer and sets up a finalizer that calls Destroy()
func wrapMixer(data *C.ALLEGRO_MIXER) *Mixer {
    self := wrapMixerRaw(data)
    return self.SetDestroyFinalizer()
}

func createMixer(freq uint, depth AudioDepth, chan_conf ChannelConf) *C.ALLEGRO_MIXER {
    return C.al_create_mixer(C.uint(freq), depth.toC(), chan_conf.toC())
}

// Creates a new mixer with no finaliser attached to it.
func CreateMixerRaw(freq uint, depth AudioDepth, chan_conf ChannelConf) *Mixer {
    return wrapMixerRaw(createMixer(freq, depth, chan_conf))
}

// Creates a new mixer with a finaliser that will call Destroy attached to it.
func CreateMixer(freq uint, depth AudioDepth, chan_conf ChannelConf) *Mixer {
    return wrapMixer(createMixer(freq, depth, chan_conf))
}

// Attaches a sample instance to the given mixer. 
func (mixer *Mixer) AttachSampleInstance(stream *SampleInstance) bool {
    return cb2b(C.al_attach_sample_instance_to_mixer(stream.handle, mixer.handle))
}

// Attaches the sample instance to the given mixer. 
func (stream *SampleInstance) Attach(mixer *Mixer) bool {
    return cb2b(C.al_attach_sample_instance_to_mixer(stream.handle, mixer.handle))
}

// Attaches an audio stream  to the given mixer. 
func (mixer *Mixer) AttachAudioStream(stream *AudioStream) bool {
    return cb2b(C.al_attach_audio_stream_to_mixer(stream.handle, mixer.handle))
}

// Attaches the audio stream to the given mixer. 
func (stream *AudioStream) Attach(mixer *Mixer) bool {
    return cb2b(C.al_attach_audio_stream_to_mixer(stream.handle, mixer.handle))
}

// Attaches a mixer to the given mixer. 
func (mixer *Mixer) AttachMixer(stream *Mixer) bool {
    return cb2b(C.al_attach_mixer_to_mixer(stream.handle, mixer.handle))
}

// Attaches the given mixer to the latter mixer. 
func (stream *Mixer) Attach(mixer *Mixer) bool {
    return cb2b(C.al_attach_mixer_to_mixer(stream.handle, mixer.handle))
}

/*
TODO:
ALLEGRO_KCM_AUDIO_FUNC(bool, al_set_mixer_postprocess_callback, (
      ALLEGRO_MIXER *mixer,
      void (*cb)(void *buf, unsigned int samples, void *data),
      void *data));
*/

// Returns the frequency of the mixer
func (self *Mixer) Frequency() uint {
    return uint(C.al_get_mixer_frequency(self.handle))
}

// Returns the gain of the mixer
func (self *Mixer) Gain() float32 {
    return float32(C.al_get_mixer_gain(self.handle))
}

// Returns the depth of the mixer
func (self *Mixer) Depth() AudioDepth {
    return AudioDepth(C.al_get_mixer_depth(self.handle))
}

// Returns the channel configuration of the mixer
func (self *Mixer) Channels() ChannelConf {
    return ChannelConf(C.al_get_mixer_channels(self.handle))
}

// Returns the quality of the mixer
func (self *Mixer) Quality() MixerQuality {
    return MixerQuality(C.al_get_mixer_quality(self.handle))
}

// Returns wheter or not the mixer is playing
func (self *Mixer) Playing() bool {
    return cb2b(C.al_get_mixer_playing(self.handle))
}

// Returns wheter or not the mixer is attached
func (self *Mixer) Attached() bool {
    return cb2b(C.al_get_mixer_attached(self.handle))
}

// Sets the frequency of the mixer.
func (self *Mixer) SetFrequency(val uint) bool {
    return cb2b(C.al_set_mixer_frequency(self.handle, C.uint(val)))
}

// Sets the quality of the mixer.
func (self *Mixer) SetQuality(val MixerQuality) bool {
    return cb2b(C.al_set_mixer_quality(self.handle, val.toC()))
}

// Sets the gain of the mixer.
func (self *Mixer) SetGain(val float32) bool {
    return cb2b(C.al_set_mixer_gain(self.handle, C.float(val)))
}

// Sets the play status of the mixer.
func (self *Mixer) SetPlaying(val bool) bool {
    return cb2b(C.al_set_mixer_playing(self.handle, b2cb(val)))
}

// Detaches the mixer from it's player
func (self *Mixer) Detach() bool {
    return cb2b(C.al_detach_mixer(self.handle))
}

// Converts a voice to it's underlying C pointer
func (self *Voice) toC() *C.ALLEGRO_VOICE {
    return (*C.ALLEGRO_VOICE)(self.handle)
}

// Destroys the voice.
func (self *Voice) Destroy() {
    if self.handle != nil {
        C.al_destroy_voice(self.toC())
    }
    self.handle = nil
}

// Wraps a C voice into a go mixer
func wrapVoiceRaw(data *C.ALLEGRO_VOICE) *Voice {
    if data == nil {
        return nil
    }
    return &Voice{data}
}

// Sets up a finalizer for this Voice Wraps a C voice that calls Destroy()
func (self *Voice) SetDestroyFinalizer() *Voice {
    if self != nil {
        runtime.SetFinalizer(self, func(me *Voice) { me.Destroy() })
    }
    return self
}

// Wraps a C voice into a go mixer and sets up a finalizer that calls Destroy()
func wrapVoice(data *C.ALLEGRO_VOICE) *Voice {
    self := wrapVoiceRaw(data)
    return self.SetDestroyFinalizer()
}

// creates a C voice 
func createVoice(freq uint, depth AudioDepth, chan_conf ChannelConf) *C.ALLEGRO_VOICE {
    return C.al_create_voice(C.uint(freq), depth.toC(), chan_conf.toC())
}

// Creates a voice
func CreateVoiceRaw(freq uint, depth AudioDepth, chan_conf ChannelConf) *Voice {
    return wrapVoiceRaw(createVoice(freq, depth, chan_conf))
}

// Creates a voice and setsup a finalizer on it that calls Destroy
func CreateVoice(freq uint, depth AudioDepth, chan_conf ChannelConf) *Voice {
    return wrapVoice(createVoice(freq, depth, chan_conf))
}

// Attaches a sample instance to the given voice. 
func (voice *Voice) AttachSampleInstance(stream *SampleInstance) bool {
    return cb2b(C.al_attach_sample_instance_to_voice(stream.handle, voice.handle))
}

// Attaches the sample instance to the given voice. 
func (stream *SampleInstance) AttachToVoice(voice *Voice) bool {
    return cb2b(C.al_attach_sample_instance_to_voice(stream.handle, voice.handle))
}

// Attaches an audio stream  to the given voice. 
func (voice *Voice) AttachAudioStream(stream *AudioStream) bool {
    return cb2b(C.al_attach_audio_stream_to_voice(stream.handle, voice.handle))
}

// Attaches the audio stream to the given voice. 
func (stream *AudioStream) AttachToVoice(voice *Voice) bool {
    return cb2b(C.al_attach_audio_stream_to_voice(stream.handle, voice.handle))
}

// Attaches the given mixer to the voice.
func (mixer *Mixer) AttachToVoice(voice *Voice) bool {
    return cb2b(C.al_attach_mixer_to_voice(mixer.handle, voice.handle))
}

// Attaches the given voice to the mixer.
func (voice *Voice) AttachMixer(mixer *Mixer) bool {
    return cb2b(C.al_attach_mixer_to_voice(mixer.handle, voice.handle))
}

// Detaches the voice.
func (voice *Voice) Detach() {
    C.al_detach_voice(voice.handle)
}

// Returns the frequency of the voice
func (self *Voice) Frequency() uint {
    return uint(C.al_get_voice_frequency(self.handle))
}

// Returns the position of the voice
func (self *Voice) Position() uint {
    return uint(C.al_get_voice_position(self.handle))
}

// Returns the depth of the voice
func (self *Voice) Depth() AudioDepth {
    return AudioDepth(C.al_get_voice_depth(self.handle))
}

// Returns the channel configuration of the voice
func (self *Voice) Channels() ChannelConf {
    return ChannelConf(C.al_get_voice_channels(self.handle))
}

// Returns wheter or not the voice is playing
func (self *Voice) Playing() bool {
    return cb2b(C.al_get_voice_playing(self.handle))
}

// Sets the position of the voice.
func (self *Voice) SetPosition(val uint) bool {
    return cb2b(C.al_set_voice_position(self.handle, C.uint(val)))
}

// Sets the play status of the voice.
func (self *Voice) SetPlaying(val bool) bool {
    return cb2b(C.al_set_voice_playing(self.handle, b2cb(val)))
}

// Installs the audio extension
func InstallAudio() bool {
    return cb2b(C.al_install_audio())
}

// Uninstalls the audio extension
func UninstallAudio() {
    C.al_uninstall_audio()
}

// Returns true if the audio extension is installed 
func IsAudioInstalled() bool {
    return cb2b(C.al_is_audio_installed())
}

// Returns the version of the audio extension
func AudioVersion() uint32 {
    return uint32(C.al_get_allegro_audio_version())
}

// Gets the amount of available channels in a channel configguration
func (self ChannelConf) ChannelCount() uint {
    return uint(C.al_get_channel_count(self.toC()))
}

// Gets the size of (foe calculating the size of allocating a sample)
func (self AudioDepth) Size() uint {
    return uint(C.al_get_audio_depth_size(self.toC()))
}

// Reserves the given amount of samples and attaches them to the default mixer
func ReserveSamples(samples int) bool {
    return cb2b(C.al_reserve_samples(C.int(samples)))
}

var defaultMixer *Mixer = nil

// Returns a pointer to the default mixer. Has no dispose finaliser set. 
func DefaultMixer() *Mixer {
    return wrapMixerRaw(C.al_get_default_mixer())
}

// Sets the mixer as the default mixer. 
func (mixer *Mixer) SetDefault() {
    // this is purely to prevent the GC from collecting this mixer.
    defaultMixer = mixer
    C.al_set_default_mixer(mixer.handle)
}

// Restores the default mixer
func RestoreDefaultMixer() {
    // GC reclaim is OK now.
    defaultMixer = nil
    C.al_restore_default_mixer()
}

// Plays a sample on the default mixer if enough samples have been reserved.
// id returns a sample if that can be used to track the sample.
func (self *Sample) Play(gain, pan, speed float32, loop PlayMode) (ok bool, id SampleId) {
    ok = cb2b(C.al_play_sample(self.handle, C.float(gain), C.float(pan), C.float(speed), loop.toC(), (&id).toC()))
    return ok, id
}

// Stops playing a sample that was started with sample.Play()  
func (self *SampleId) Stop() {
    C.al_stop_sample(self.toC())
}

// Stops playing all samples on the default mixer
func StopSamples() {
    C.al_stop_samples()
}

/*
Todo: 
ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_sample_loader, (const char *ext,
    ALLEGRO_SAMPLE *(*loader)(const char *filename)));
ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_sample_saver, (const char *ext,
    bool (*saver)(const char *filename, ALLEGRO_SAMPLE *spl)));
ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_audio_stream_loader, (const char *ext,
    ALLEGRO_AUDIO_STREAM *(*stream_loader)(const char *filename,
        size_t buffer_count, unsigned int samples)));

ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_sample_loader_f, (const char *ext,
    ALLEGRO_SAMPLE *(*loader)(ALLEGRO_FILE *fp)));
ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_sample_saver_f, (const char *ext,
    bool (*saver)(ALLEGRO_FILE *fp, ALLEGRO_SAMPLE *spl)));
ALLEGRO_KCM_AUDIO_FUNC(bool, al_register_audio_stream_loader_f, (const char *ext,
    ALLEGRO_AUDIO_STREAM *(*stream_loader)(ALLEGRO_FILE *fp,
        size_t buffer_count, unsigned int samples)));
*/

// Loads a C sample from a filename
func loadSample(filename string) *C.ALLEGRO_SAMPLE {
    cstr := cstr(filename)
    defer cstrFree(cstr)
    return C.al_load_sample(cstr)
}

// Loads a sample from a filename and sets up no finalizer 
func LoadSampleRaw(filename string) *Sample {
    return wrapSampleRaw(loadSample(filename))
}

// Loads a sample from a filename and sets up a finalizer 
func LoadSample(filename string) *Sample {
    return LoadSampleRaw(filename).SetDestroyFinalizer()
}

// Saves a sample to a given filename
func (self *Sample) Save(filename string) bool {
    cstr := cstr(filename)
    defer cstrFree(cstr)
    return cb2b(C.al_save_sample(cstr, self.handle))
}

// Loads a C audio stream sample from a filename
func loadAudioStream(filename string, buffer_count, samples uint) *C.ALLEGRO_AUDIO_STREAM {
    cstr := cstr(filename)
    defer cstrFree(cstr)
    return C.al_load_audio_stream(cstr, C.size_t(buffer_count), C.uint(samples))
}

// Loads a sample from a filename and sets up no finalizer 
func LoadAudioStreamRaw(filename string, buffer_count, samples uint) *AudioStream {
    return wrapAudioStreamRaw(loadAudioStream(filename, buffer_count, samples))
}

// Loads a sample from a filename and sets up a finalizer 
func LoadAudioStream(filename string, buffer_count, samples uint) *AudioStream {
    return LoadAudioStreamRaw(filename, buffer_count, samples).SetDestroyFinalizer()
}

// Allegro's own file for cross platform and physfs reasons.
type File struct {
    handle *C.ALLEGRO_FILE
}

// Closes the Allegro file
func (self *File) Close() {
    if self.handle != nil {
        C.al_fclose(self.handle)
    }
    self.handle = nil
}

// Returns the low level handle of the file 
func (self *File) toC() * C.ALLEGRO_FILE {
    return self.handle
}

// Wraps an ALLEGRO_FILE into a File
func wrapFileRaw(file *C.ALLEGRO_FILE) *File {
    if file == nil {
        return nil
    }
    return &File{file}
}

// Opens an Allegro File
func openFile(filename, mode string) *C.ALLEGRO_FILE {
    cfilename := cstr(filename)
    defer cstrFree(cfilename)
    cmode := cstr(mode)
    defer cstrFree(cmode)
    return C.al_fopen(cfilename, cmode)
}

// Sets up a finalizer for this File that calls Close()
func (self *File) SetCloseFinalizer() *File {
    if self != nil {
        runtime.SetFinalizer(self, func(me *File) { me.Close() })
    }
    return self
}

// Wraps a file and sets up a finalizer that calls Destroy()
func wrapFile(data *C.ALLEGRO_FILE) *File {
    self := wrapFileRaw(data)
    return self.SetCloseFinalizer()
}

// Opens a file with no finalizer set
func OpenFileRaw(filename, mode string) *File {
    self := openFile(filename, mode)
    return wrapFileRaw(self)
}

// Opens a file with a Close finalizer set
func OpenFile(filename, mode string) *File {
    self := OpenFileRaw(filename, mode)
    return self.SetCloseFinalizer()
}

// Loads a Sample from a File. Filetype is a file extension that identifies the file type 
// like (.wav, .ogg, etc))
func (self *File) loadSample(filetype string) *C.ALLEGRO_SAMPLE {
    cfiletype := cstr(filetype)
    defer cstrFree(cfiletype)
    return C.al_load_sample_f(self.handle, cfiletype)
}

// Saves a Sample to a File. Filetype is a file extension that identifies the file type 
func (self *File) SaveSample(filetype string, sample *Sample) bool {
    cfiletype := cstr(filetype)
    defer cstrFree(cfiletype)
    return cb2b(C.al_save_sample_f(self.handle, cfiletype, sample.handle))
}

// Loads an ALLEGRO_AUDIO_STREAM from a file. Filetype is a file extension
// that identifies the file type (.ogg, etc)
func (self *File) loadAudioStream(filetype string, buffer_count,
    samples uint) *C.ALLEGRO_AUDIO_STREAM {
    cfiletype := cstr(filetype)
    defer cstrFree(cfiletype)
    return C.al_load_audio_stream_f(self.handle, cfiletype,
        C.size_t(buffer_count), C.uint(samples))
}

// Loads a Sample from a File. Filetype is a file extension that identifies the file type 
// like (.wav, .ogg, etc))
func (self *File) LoadSampleRaw(filetype string) *Sample {
    return wrapSampleRaw(loadSample(filetype))
}

// Loads a Sample from a File. Filetype is a file extension that identifies the file type 
// like (.wav, .ogg, etc)). Sets up a finalizer. 
func (self *File) LoadSample(filetype string) *Sample {
    return LoadSampleRaw(filetype).SetDestroyFinalizer()
}

// Loads an AudioStream from a file. Filetype is a file extension
// that identifies the file type (.ogg, etc)
func (self *File) LoadAudioStreamRaw(filetype string, buffer_count,
    samples uint) *AudioStream {
    return wrapAudioStreamRaw(loadAudioStream(filetype, buffer_count, samples))
}

// Loads an AudioStream from a file. Filetype is a file extension
// that identifies the file type (.ogg, etc). Sets up a finalizer.
func (self *File) LoadAudioStream(filetype string, buffer_count,
    samples uint) *AudioStream {
    return LoadAudioStreamRaw(filetype, buffer_count, samples).SetDestroyFinalizer()
}

// Converts a recorder to it's underlying C pointer
func (self *AudioRecorder) toC() *C.ALLEGRO_AUDIO_RECORDER {
    return (*C.ALLEGRO_AUDIO_RECORDER)(self.handle)
}

// Destroys the recorder.
func (self *AudioRecorder) Destroy() {
    if self.handle != nil {
        C.al_destroy_audio_recorder(self.toC())
    }
    self.handle = nil
}

// Wraps a C recorder into a go mixer
func wrapAudioRecorderRaw(data *C.ALLEGRO_AUDIO_RECORDER) *AudioRecorder {
    if data == nil {
        return nil
    }
    return &AudioRecorder{data}
}

// Sets up a finalizer for this AudioRecorder Wraps a C recorder that calls Destroy()
func (self *AudioRecorder) SetDestroyFinalizer() *AudioRecorder {
    if self != nil {
        runtime.SetFinalizer(self, func(me *AudioRecorder) { me.Destroy() })
    }
    return self
}

// Wraps a C recorder into a go recorder and sets up a finalizer that calls Destroy()
func wrapAudioRecorder(data *C.ALLEGRO_AUDIO_RECORDER) *AudioRecorder {
    self := wrapAudioRecorderRaw(data)
    return self.SetDestroyFinalizer()
}

// Creates a C recorder 
func createAudioRecorder(fragment_count, samples, freq uint,
    depth AudioDepth, chan_conf ChannelConf) *C.ALLEGRO_AUDIO_RECORDER {
    return C.al_create_audio_recorder(C.size_t(fragment_count), C.uint(samples),
        C.uint(freq), depth.toC(), chan_conf.toC())
}

// Creates an Audio Recorder and sets no finalizer
func CreateAudioRecorderRaw(fragment_count, samples, freq uint,
    depth AudioDepth, chan_conf ChannelConf) *AudioRecorder {
    return wrapAudioRecorderRaw(createAudioRecorder(fragment_count, samples, freq, depth, chan_conf))
}

// Creates an Audio Recorder and sets a finalizer
func CreateAudioRecorder(fragment_count, samples, freq uint,
    depth AudioDepth, chan_conf ChannelConf) *AudioRecorder {
    return CreateAudioRecorderRaw(fragment_count, samples,
        freq, depth, chan_conf).SetDestroyFinalizer()
}

// Starts recording on the audio recorder.
func (self *AudioRecorder) Start() bool {
    return cb2b(C.al_start_audio_recorder(self.handle))
}

// Stops recording on the audio recorder.
func (self *AudioRecorder) Stop() {
    C.al_stop_audio_recorder(self.handle)
}

// Gets the audio recorder's event source
func (self *AudioRecorder) EventSource() *EventSource {
    return wrapEventSourceRaw(C.al_get_audio_recorder_event_source(self.handle))
}

// Converts to AudioRecorderEvent
func wrapAudioRecorderEvent(event *C.ALLEGRO_AUDIO_RECORDER_EVENT) *AudioRecorderEvent {
    return (*AudioRecorderEvent)(event)
}

// Converts an event into an allegro recorder event 
func (self *Event) AudioRecorderEvent() *AudioRecorderEvent {
    return wrapAudioRecorderEvent(C.al_get_audio_recorder_event(self.toC()))
}

// Gets an unsafe pointer to the recorder event's buffer 
func (self *AudioRecorderEvent) BufferPointer() unsafe.Pointer {
    return self.buffer
}

// Gets the amount of samples for this recorder event
func (self *AudioRecorderEvent) Samples() uint {
    return uint(self.samples)
}

// Gets the recorder's buffer copied into a byte slice
func (self *AudioRecorderEvent) Buffer() []byte {
    return C.GoBytes(self.buffer, C.int(self.samples))
}