1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2012 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22 #include "SDL_config.h"
23
24 /* Allow access to a raw mixing buffer */
25
26 #ifdef HAVE_SIGNAL_H
27 #include <signal.h>
28 #endif
29 #include <unistd.h>
30
31 #include "SDL_timer.h"
32 #include "SDL_audio.h"
33 #include "../SDL_audiomem.h"
34 #include "../SDL_audio_c.h"
35 #include "../SDL_audiodev_c.h"
36 #include "SDL_artsaudio.h"
37
38 #ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC
39 #include "SDL_name.h"
40 #include "SDL_loadso.h"
41 #else
42 #define SDL_NAME(X) X
43 #endif
44
45 /* The tag name used by artsc audio */
46 #define ARTS_DRIVER_NAME "arts"
47
48 /* Audio driver functions */
49 static int ARTS_OpenAudio(_THIS, SDL_AudioSpec *spec);
50 static void ARTS_WaitAudio(_THIS);
51 static void ARTS_PlayAudio(_THIS);
52 static Uint8 *ARTS_GetAudioBuf(_THIS);
53 static void ARTS_CloseAudio(_THIS);
54
55 #ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC
56
57 static const char *arts_library = SDL_AUDIO_DRIVER_ARTS_DYNAMIC;
58 static void *arts_handle = NULL;
59 static int arts_loaded = 0;
60
61 static int (*SDL_NAME(arts_init))(void);
62 static void (*SDL_NAME(arts_free))(void);
63 static arts_stream_t (*SDL_NAME(arts_play_stream))(int rate, int bits, int channels, const char *name);
64 static int (*SDL_NAME(arts_stream_set))(arts_stream_t s, arts_parameter_t param, int value);
65 static int (*SDL_NAME(arts_stream_get))(arts_stream_t s, arts_parameter_t param);
66 static int (*SDL_NAME(arts_write))(arts_stream_t s, const void *buffer, int count);
67 static void (*SDL_NAME(arts_close_stream))(arts_stream_t s);
68 static int (*SDL_NAME(arts_suspend))(void);
69 static int (*SDL_NAME(arts_suspended))(void);
70 static const char *(*SDL_NAME(arts_error_text))(int errorcode);
71
72 static struct {
73 const char *name;
74 void **func;
75 } arts_functions[] = {
76 { "arts_init", (void **)&SDL_NAME(arts_init) },
77 { "arts_free", (void **)&SDL_NAME(arts_free) },
78 { "arts_play_stream", (void **)&SDL_NAME(arts_play_stream) },
79 { "arts_stream_set", (void **)&SDL_NAME(arts_stream_set) },
80 { "arts_stream_get", (void **)&SDL_NAME(arts_stream_get) },
81 { "arts_write", (void **)&SDL_NAME(arts_write) },
82 { "arts_close_stream", (void **)&SDL_NAME(arts_close_stream) },
83 { "arts_suspend", (void **)&SDL_NAME(arts_suspend) },
84 { "arts_suspended", (void **)&SDL_NAME(arts_suspended) },
85 { "arts_error_text", (void **)&SDL_NAME(arts_error_text) },
86 };
87
UnloadARTSLibrary()88 static void UnloadARTSLibrary()
89 {
90 if ( arts_loaded ) {
91 SDL_UnloadObject(arts_handle);
92 arts_handle = NULL;
93 arts_loaded = 0;
94 }
95 }
96
LoadARTSLibrary(void)97 static int LoadARTSLibrary(void)
98 {
99 int i, retval = -1;
100
101 arts_handle = SDL_LoadObject(arts_library);
102 if ( arts_handle ) {
103 arts_loaded = 1;
104 retval = 0;
105 for ( i=0; i<SDL_arraysize(arts_functions); ++i ) {
106 *arts_functions[i].func = SDL_LoadFunction(arts_handle, arts_functions[i].name);
107 if ( !*arts_functions[i].func ) {
108 retval = -1;
109 UnloadARTSLibrary();
110 break;
111 }
112 }
113 }
114 return retval;
115 }
116
117 #else
118
UnloadARTSLibrary()119 static void UnloadARTSLibrary()
120 {
121 return;
122 }
123
LoadARTSLibrary(void)124 static int LoadARTSLibrary(void)
125 {
126 return 0;
127 }
128
129 #endif /* SDL_AUDIO_DRIVER_ARTS_DYNAMIC */
130
131 /* Audio driver bootstrap functions */
132
ARTS_Suspend(void)133 static int ARTS_Suspend(void)
134 {
135 const Uint32 abortms = SDL_GetTicks() + 3000; /* give up after 3 secs */
136 while ( (!SDL_NAME(arts_suspended)()) && (SDL_GetTicks() < abortms) ) {
137 if ( SDL_NAME(arts_suspend)() ) {
138 break;
139 }
140 }
141
142 return SDL_NAME(arts_suspended)();
143 }
144
Audio_Available(void)145 static int Audio_Available(void)
146 {
147 int available = 0;
148
149 if ( LoadARTSLibrary() < 0 ) {
150 return available;
151 }
152 if ( SDL_NAME(arts_init)() == 0 ) {
153 if ( ARTS_Suspend() ) {
154 /* Play a stream so aRts doesn't crash */
155 arts_stream_t stream2;
156 stream2=SDL_NAME(arts_play_stream)(44100, 16, 2, "SDL");
157 SDL_NAME(arts_write)(stream2, "", 0);
158 SDL_NAME(arts_close_stream)(stream2);
159 available = 1;
160 }
161 SDL_NAME(arts_free)();
162 }
163 UnloadARTSLibrary();
164
165 return available;
166 }
167
Audio_DeleteDevice(SDL_AudioDevice * device)168 static void Audio_DeleteDevice(SDL_AudioDevice *device)
169 {
170 SDL_free(device->hidden);
171 SDL_free(device);
172 UnloadARTSLibrary();
173 }
174
Audio_CreateDevice(int devindex)175 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
176 {
177 SDL_AudioDevice *this;
178
179 /* Initialize all variables that we clean on shutdown */
180 LoadARTSLibrary();
181 this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
182 if ( this ) {
183 SDL_memset(this, 0, (sizeof *this));
184 this->hidden = (struct SDL_PrivateAudioData *)
185 SDL_malloc((sizeof *this->hidden));
186 }
187 if ( (this == NULL) || (this->hidden == NULL) ) {
188 SDL_OutOfMemory();
189 if ( this ) {
190 SDL_free(this);
191 }
192 return(0);
193 }
194 SDL_memset(this->hidden, 0, (sizeof *this->hidden));
195 stream = 0;
196
197 /* Set the function pointers */
198 this->OpenAudio = ARTS_OpenAudio;
199 this->WaitAudio = ARTS_WaitAudio;
200 this->PlayAudio = ARTS_PlayAudio;
201 this->GetAudioBuf = ARTS_GetAudioBuf;
202 this->CloseAudio = ARTS_CloseAudio;
203
204 this->free = Audio_DeleteDevice;
205
206 return this;
207 }
208
209 AudioBootStrap ARTS_bootstrap = {
210 ARTS_DRIVER_NAME, "Analog Realtime Synthesizer",
211 Audio_Available, Audio_CreateDevice
212 };
213
214 /* This function waits until it is possible to write a full sound buffer */
ARTS_WaitAudio(_THIS)215 static void ARTS_WaitAudio(_THIS)
216 {
217 Sint32 ticks;
218
219 /* Check to see if the thread-parent process is still alive */
220 { static int cnt = 0;
221 /* Note that this only works with thread implementations
222 that use a different process id for each thread.
223 */
224 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
225 if ( kill(parent, 0) < 0 ) {
226 this->enabled = 0;
227 }
228 }
229 }
230
231 /* Use timer for general audio synchronization */
232 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
233 if ( ticks > 0 ) {
234 SDL_Delay(ticks);
235 }
236 }
237
ARTS_PlayAudio(_THIS)238 static void ARTS_PlayAudio(_THIS)
239 {
240 int written;
241
242 /* Write the audio data */
243 written = SDL_NAME(arts_write)(stream, mixbuf, mixlen);
244
245 /* If timer synchronization is enabled, set the next write frame */
246 if ( frame_ticks ) {
247 next_frame += frame_ticks;
248 }
249
250 /* If we couldn't write, assume fatal error for now */
251 if ( written < 0 ) {
252 this->enabled = 0;
253 }
254 #ifdef DEBUG_AUDIO
255 fprintf(stderr, "Wrote %d bytes of audio data\n", written);
256 #endif
257 }
258
ARTS_GetAudioBuf(_THIS)259 static Uint8 *ARTS_GetAudioBuf(_THIS)
260 {
261 return(mixbuf);
262 }
263
ARTS_CloseAudio(_THIS)264 static void ARTS_CloseAudio(_THIS)
265 {
266 if ( mixbuf != NULL ) {
267 SDL_FreeAudioMem(mixbuf);
268 mixbuf = NULL;
269 }
270 if ( stream ) {
271 SDL_NAME(arts_close_stream)(stream);
272 stream = 0;
273 }
274 SDL_NAME(arts_free)();
275 }
276
ARTS_OpenAudio(_THIS,SDL_AudioSpec * spec)277 static int ARTS_OpenAudio(_THIS, SDL_AudioSpec *spec)
278 {
279 int bits, frag_spec;
280 Uint16 test_format, format;
281 int error_code;
282
283 /* Reset the timer synchronization flag */
284 frame_ticks = 0.0;
285
286 mixbuf = NULL;
287
288 /* Try for a closest match on audio format */
289 format = 0;
290 bits = 0;
291 for ( test_format = SDL_FirstAudioFormat(spec->format);
292 ! format && test_format; ) {
293 #ifdef DEBUG_AUDIO
294 fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
295 #endif
296 switch ( test_format ) {
297 case AUDIO_U8:
298 bits = 8;
299 format = 1;
300 break;
301 case AUDIO_S16LSB:
302 bits = 16;
303 format = 1;
304 break;
305 default:
306 format = 0;
307 break;
308 }
309 if ( ! format ) {
310 test_format = SDL_NextAudioFormat();
311 }
312 }
313 if ( format == 0 ) {
314 SDL_SetError("Couldn't find any hardware audio formats");
315 return(-1);
316 }
317 spec->format = test_format;
318
319 error_code = SDL_NAME(arts_init)();
320 if ( error_code != 0 ) {
321 SDL_SetError("Unable to initialize ARTS: %s", SDL_NAME(arts_error_text)(error_code));
322 return(-1);
323 }
324 if ( ! ARTS_Suspend() ) {
325 SDL_SetError("ARTS can not open audio device");
326 return(-1);
327 }
328 stream = SDL_NAME(arts_play_stream)(spec->freq, bits, spec->channels, "SDL");
329
330 /* Calculate the final parameters for this audio specification */
331 SDL_CalculateAudioSpec(spec);
332
333 /* Determine the power of two of the fragment size */
334 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
335 if ( (0x01<<frag_spec) != spec->size ) {
336 SDL_SetError("Fragment size must be a power of two");
337 return(-1);
338 }
339 frag_spec |= 0x00020000; /* two fragments, for low latency */
340
341 #ifdef ARTS_P_PACKET_SETTINGS
342 SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_SETTINGS, frag_spec);
343 #else
344 SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_SIZE, frag_spec&0xffff);
345 SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_COUNT, frag_spec>>16);
346 #endif
347 spec->size = SDL_NAME(arts_stream_get)(stream, ARTS_P_PACKET_SIZE);
348
349 /* Allocate mixing buffer */
350 mixlen = spec->size;
351 mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
352 if ( mixbuf == NULL ) {
353 return(-1);
354 }
355 SDL_memset(mixbuf, spec->silence, spec->size);
356
357 /* Get the parent process id (we're the parent of the audio thread) */
358 parent = getpid();
359
360 /* We're ready to rock and roll. :-) */
361 return(0);
362 }
363