Atlas - SDL_sysaudio.h
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "../SDL_internal.h"
22
23#ifndef SDL_sysaudio_h_
24#define SDL_sysaudio_h_
25
26#include "SDL_mutex.h"
27#include "SDL_thread.h"
28#include "../SDL_dataqueue.h"
29#include "./SDL_audio_c.h"
30
31/* !!! FIXME: These are wordy and unlocalized... */
32#define DEFAULT_OUTPUT_DEVNAME "System audio output device"
33#define DEFAULT_INPUT_DEVNAME "System audio capture device"
34
35/* The SDL audio driver */
36typedef struct SDL_AudioDevice SDL_AudioDevice;
37#define _THIS   SDL_AudioDevice *_this
38
39/* Audio targets should call this as devices are added to the system (such as
40   a USB headset being plugged in), and should also be called for
41   for every device found during DetectDevices(). */
42extern void SDL_AddAudioDevice(const int iscapture, const char *name, void *handle);
43
44/* Audio targets should call this as devices are removed, so SDL can update
45   its list of available devices. */
46extern void SDL_RemoveAudioDevice(const int iscapture, void *handle);
47
48/* Audio targets should call this if an opened audio device is lost while
49   being used. This can happen due to i/o errors, or a device being unplugged,
50   etc. If the device is totally gone, please also call SDL_RemoveAudioDevice()
51   as appropriate so SDL's list of devices is accurate. */
52extern void SDL_OpenedAudioDeviceDisconnected(SDL_AudioDevice *device);
53
54/* This is the size of a packet when using SDL_QueueAudio(). We allocate
55   these as necessary and pool them, under the assumption that we'll
56   eventually end up with a handful that keep recycling, meeting whatever
57   the app needs. We keep packing data tightly as more arrives to avoid
58   wasting space, and if we get a giant block of data, we'll split them
59   into multiple packets behind the scenes. My expectation is that most
60   apps will have 2-3 of these in the pool. 8k should cover most needs, but
61   if this is crippling for some embedded system, we can #ifdef this.
62   The system preallocates enough packets for 2 callbacks' worth of data. */
63#define SDL_AUDIOBUFFERQUEUE_PACKETLEN (8 * 1024)
64
65typedef struct SDL_AudioDriverImpl
66{
67    void (*DetectDevices) (void);
68    int (*OpenDevice) (_THIS, void *handle, const char *devname, int iscapture);
69    void (*ThreadInit) (_THIS); /* Called by audio thread at start */
70    void (*ThreadDeinit) (_THIS); /* Called by audio thread at end */
71    void (*BeginLoopIteration)(_THIS);  /* Called by audio thread at top of loop */
72    void (*WaitDevice) (_THIS);
73    void (*PlayDevice) (_THIS);
74    int (*GetPendingBytes) (_THIS);
75    Uint8 *(*GetDeviceBuf) (_THIS);
76    int (*CaptureFromDevice) (_THIS, void *buffer, int buflen);
77    void (*FlushCapture) (_THIS);
78    void (*PrepareToClose) (_THIS);  /**< Called between run and draining wait for playback devices */
79    void (*CloseDevice) (_THIS);
80    void (*LockDevice) (_THIS);
81    void (*UnlockDevice) (_THIS);
82    void (*FreeDeviceHandle) (void *handle);  /**< SDL is done with handle from SDL_AddAudioDevice() */
83    void (*Deinitialize) (void);
84
85    /* !!! FIXME: add pause(), so we can optimize instead of mixing silence. */
86
87    /* Some flags to push duplicate code into the core and reduce #ifdefs. */
88    /* !!! FIXME: these should be SDL_bool */
89    int ProvidesOwnCallbackThread;
90    int SkipMixerLock;
91    int HasCaptureSupport;
92    int OnlyHasDefaultOutputDevice;
93    int OnlyHasDefaultCaptureDevice;
94    int AllowsArbitraryDeviceNames;
95} SDL_AudioDriverImpl;
96
97
98typedef struct SDL_AudioDeviceItem
99{
100    void *handle;
101    struct SDL_AudioDeviceItem *next;
102    char name[SDL_VARIABLE_LENGTH_ARRAY];
103} SDL_AudioDeviceItem;
104
105
106typedef struct SDL_AudioDriver
107{
108    /* * * */
109    /* The name of this audio driver */
110    const char *name;
111
112    /* * * */
113    /* The description of this audio driver */
114    const char *desc;
115
116    SDL_AudioDriverImpl impl;
117
118    /* A mutex for device detection */
119    SDL_mutex *detectionLock;
120    SDL_bool captureDevicesRemoved;
121    SDL_bool outputDevicesRemoved;
122    int outputDeviceCount;
123    int inputDeviceCount;
124    SDL_AudioDeviceItem *outputDevices;
125    SDL_AudioDeviceItem *inputDevices;
126} SDL_AudioDriver;
127
128
129/* Define the SDL audio driver structure */
130struct SDL_AudioDevice
131{
132    /* * * */
133    /* Data common to all devices */
134    SDL_AudioDeviceID id;
135
136    /* The device's current audio specification */
137    SDL_AudioSpec spec;
138
139    /* The callback's expected audio specification (converted vs device's spec). */
140    SDL_AudioSpec callbackspec;
141
142    /* Stream that converts and resamples. NULL if not needed. */
143    SDL_AudioStream *stream;
144
145    /* Current state flags */
146    SDL_atomic_t shutdown; /* true if we are signaling the play thread to end. */
147    SDL_atomic_t enabled;  /* true if device is functioning and connected. */
148    SDL_atomic_t paused;
149    SDL_bool iscapture;
150
151    /* Scratch buffer used in the bridge between SDL and the user callback. */
152    Uint8 *work_buffer;
153
154    /* Size, in bytes, of work_buffer. */
155    Uint32 work_buffer_len;
156
157    /* A mutex for locking the mixing buffers */
158    SDL_mutex *mixer_lock;
159
160    /* A thread to feed the audio device */
161    SDL_Thread *thread;
162    SDL_threadID threadid;
163
164    /* Queued buffers (if app not using callback). */
165    SDL_DataQueue *buffer_queue;
166
167    /* * * */
168    /* Data private to this driver */
169    struct SDL_PrivateAudioData *hidden;
170
171    void *handle;
172};
173#undef _THIS
174
175typedef struct AudioBootStrap
176{
177    const char *name;
178    const char *desc;
179    int (*init) (SDL_AudioDriverImpl * impl);
180    int demand_only;  /* 1==request explicitly, or it won't be available. */
181} AudioBootStrap;
182
183/* Not all of these are available in a given build. Use #ifdefs, etc. */
184extern AudioBootStrap PULSEAUDIO_bootstrap;
185extern AudioBootStrap ALSA_bootstrap;
186extern AudioBootStrap JACK_bootstrap;
187extern AudioBootStrap SNDIO_bootstrap;
188extern AudioBootStrap NETBSDAUDIO_bootstrap;
189extern AudioBootStrap DSP_bootstrap;
190extern AudioBootStrap QSAAUDIO_bootstrap;
191extern AudioBootStrap SUNAUDIO_bootstrap;
192extern AudioBootStrap ARTS_bootstrap;
193extern AudioBootStrap ESD_bootstrap;
194extern AudioBootStrap NACLAUDIO_bootstrap;
195extern AudioBootStrap NAS_bootstrap;
196extern AudioBootStrap WASAPI_bootstrap;
197extern AudioBootStrap DSOUND_bootstrap;
198extern AudioBootStrap WINMM_bootstrap;
199extern AudioBootStrap PAUDIO_bootstrap;
200extern AudioBootStrap HAIKUAUDIO_bootstrap;
201extern AudioBootStrap COREAUDIO_bootstrap;
202extern AudioBootStrap DISKAUDIO_bootstrap;
203extern AudioBootStrap DUMMYAUDIO_bootstrap;
204extern AudioBootStrap FUSIONSOUND_bootstrap;
205extern AudioBootStrap ANDROIDAUDIO_bootstrap;
206extern AudioBootStrap PSPAUDIO_bootstrap;
207extern AudioBootStrap EMSCRIPTENAUDIO_bootstrap;
208
209#endif /* SDL_sysaudio_h_ */
210
211/* vi: set ts=4 sw=4 expandtab: */
212
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