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SDL_artsaudio.c
357 lines (305 loc) · 9.33 KB
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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/* Allow access to a raw mixing buffer */
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#include "SDL_timer.h"
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#include "SDL_audio.h"
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#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "../SDL_audiodev_c.h"
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#include "SDL_artsaudio.h"
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#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC
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#include "SDL_name.h"
#include "SDL_loadso.h"
#else
#define SDL_NAME(X) X
#endif
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/* The tag name used by artsc audio */
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#define ARTS_DRIVER_NAME "arts"
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/* Audio driver functions */
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static int ARTS_OpenAudio(_THIS, SDL_AudioSpec * spec);
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static void ARTS_WaitAudio(_THIS);
static void ARTS_PlayAudio(_THIS);
static Uint8 *ARTS_GetAudioBuf(_THIS);
static void ARTS_CloseAudio(_THIS);
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#ifdef SDL_AUDIO_DRIVER_ARTS_DYNAMIC
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static const char *arts_library = SDL_AUDIO_DRIVER_ARTS_DYNAMIC;
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static void *arts_handle = NULL;
static int arts_loaded = 0;
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static int (*SDL_NAME(arts_init)) (void);
static void (*SDL_NAME(arts_free)) (void);
static arts_stream_t(*SDL_NAME(arts_play_stream)) (int rate, int bits,
int channels,
const char *name);
static int (*SDL_NAME(arts_stream_set)) (arts_stream_t s,
arts_parameter_t param, int value);
static int (*SDL_NAME(arts_stream_get)) (arts_stream_t s,
arts_parameter_t param);
static int (*SDL_NAME(arts_write)) (arts_stream_t s, const void *buffer,
int count);
static void (*SDL_NAME(arts_close_stream)) (arts_stream_t s);
static struct
{
const char *name;
void **func;
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} arts_functions[] = {
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{
"arts_init", (void **) &SDL_NAME(arts_init)}, {
"arts_free", (void **) &SDL_NAME(arts_free)}, {
"arts_play_stream", (void **) &SDL_NAME(arts_play_stream)}, {
"arts_stream_set", (void **) &SDL_NAME(arts_stream_set)}, {
"arts_stream_get", (void **) &SDL_NAME(arts_stream_get)}, {
"arts_write", (void **) &SDL_NAME(arts_write)}, {
"arts_close_stream", (void **) &SDL_NAME(arts_close_stream)},};
static void
UnloadARTSLibrary()
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{
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if (arts_loaded) {
SDL_UnloadObject(arts_handle);
arts_handle = NULL;
arts_loaded = 0;
}
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}
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static int
LoadARTSLibrary(void)
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{
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int i, retval = -1;
arts_handle = SDL_LoadObject(arts_library);
if (arts_handle) {
arts_loaded = 1;
retval = 0;
for (i = 0; i < SDL_arraysize(arts_functions); ++i) {
*arts_functions[i].func =
SDL_LoadFunction(arts_handle, arts_functions[i].name);
if (!*arts_functions[i].func) {
retval = -1;
UnloadARTSLibrary();
break;
}
}
}
return retval;
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}
#else
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static void
UnloadARTSLibrary()
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{
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return;
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}
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static int
LoadARTSLibrary(void)
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{
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return 0;
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}
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#endif /* SDL_AUDIO_DRIVER_ARTS_DYNAMIC */
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/* Audio driver bootstrap functions */
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static int
Audio_Available(void)
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{
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int available = 0;
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if (LoadARTSLibrary() < 0) {
return available;
}
if (SDL_NAME(arts_init) () == 0) {
#define ARTS_CRASH_HACK /* Play a stream so aRts doesn't crash */
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#ifdef ARTS_CRASH_HACK
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arts_stream_t stream2;
stream2 = SDL_NAME(arts_play_stream) (44100, 16, 2, "SDL");
SDL_NAME(arts_write) (stream2, "", 0);
SDL_NAME(arts_close_stream) (stream2);
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#endif
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available = 1;
SDL_NAME(arts_free) ();
}
UnloadARTSLibrary();
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return available;
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}
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static void
Audio_DeleteDevice(SDL_AudioDevice * device)
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{
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SDL_free(device->hidden);
SDL_free(device);
UnloadARTSLibrary();
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}
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static SDL_AudioDevice *
Audio_CreateDevice(int devindex)
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{
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SDL_AudioDevice *this;
/* Initialize all variables that we clean on shutdown */
LoadARTSLibrary();
this = (SDL_AudioDevice *) SDL_malloc(sizeof(SDL_AudioDevice));
if (this) {
SDL_memset(this, 0, (sizeof *this));
this->hidden = (struct SDL_PrivateAudioData *)
SDL_malloc((sizeof *this->hidden));
}
if ((this == NULL) || (this->hidden == NULL)) {
SDL_OutOfMemory();
if (this) {
SDL_free(this);
}
return (0);
}
SDL_memset(this->hidden, 0, (sizeof *this->hidden));
stream = 0;
/* Set the function pointers */
this->OpenAudio = ARTS_OpenAudio;
this->WaitAudio = ARTS_WaitAudio;
this->PlayAudio = ARTS_PlayAudio;
this->GetAudioBuf = ARTS_GetAudioBuf;
this->CloseAudio = ARTS_CloseAudio;
this->free = Audio_DeleteDevice;
return this;
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}
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AudioBootStrap ARTS_bootstrap = {
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ARTS_DRIVER_NAME, "Analog Realtime Synthesizer",
Audio_Available, Audio_CreateDevice
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};
/* This function waits until it is possible to write a full sound buffer */
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static void
ARTS_WaitAudio(_THIS)
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{
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Sint32 ticks;
/* Check to see if the thread-parent process is still alive */
{
static int cnt = 0;
/* Note that this only works with thread implementations
that use a different process id for each thread.
*/
if (parent && (((++cnt) % 10) == 0)) { /* Check every 10 loops */
if (kill(parent, 0) < 0) {
this->enabled = 0;
}
}
}
/* Use timer for general audio synchronization */
ticks = ((Sint32) (next_frame - SDL_GetTicks())) - FUDGE_TICKS;
if (ticks > 0) {
SDL_Delay(ticks);
}
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}
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static void
ARTS_PlayAudio(_THIS)
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{
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int written;
/* Write the audio data */
written = SDL_NAME(arts_write) (stream, mixbuf, mixlen);
/* If timer synchronization is enabled, set the next write frame */
if (frame_ticks) {
next_frame += frame_ticks;
}
/* If we couldn't write, assume fatal error for now */
if (written < 0) {
this->enabled = 0;
}
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#ifdef DEBUG_AUDIO
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fprintf(stderr, "Wrote %d bytes of audio data\n", written);
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#endif
}
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static Uint8 *
ARTS_GetAudioBuf(_THIS)
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{
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return (mixbuf);
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}
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static void
ARTS_CloseAudio(_THIS)
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{
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if (mixbuf != NULL) {
SDL_FreeAudioMem(mixbuf);
mixbuf = NULL;
}
if (stream) {
SDL_NAME(arts_close_stream) (stream);
stream = 0;
}
SDL_NAME(arts_free) ();
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}
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static int
ARTS_OpenAudio(_THIS, SDL_AudioSpec * spec)
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{
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int bits, frag_spec;
Uint16 test_format, format;
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/* Reset the timer synchronization flag */
frame_ticks = 0.0;
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mixbuf = NULL;
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/* Try for a closest match on audio format */
format = 0;
bits = 0;
for (test_format = SDL_FirstAudioFormat(spec->format);
!format && test_format;) {
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#ifdef DEBUG_AUDIO
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fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
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#endif
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switch (test_format) {
case AUDIO_U8:
bits = 8;
format = 1;
break;
case AUDIO_S16LSB:
bits = 16;
format = 1;
break;
default:
format = 0;
break;
}
if (!format) {
test_format = SDL_NextAudioFormat();
}
}
if (format == 0) {
SDL_SetError("Couldn't find any hardware audio formats");
return (-1);
}
spec->format = test_format;
if (SDL_NAME(arts_init) () != 0) {
SDL_SetError("Unable to initialize ARTS");
return (-1);
}
stream =
SDL_NAME(arts_play_stream) (spec->freq, bits, spec->channels, "SDL");
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(spec);
/* Determine the power of two of the fragment size */
for (frag_spec = 0; (0x01 << frag_spec) < spec->size; ++frag_spec);
if ((0x01 << frag_spec) != spec->size) {
SDL_SetError("Fragment size must be a power of two");
return (-1);
}
frag_spec |= 0x00020000; /* two fragments, for low latency */
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#ifdef ARTS_P_PACKET_SETTINGS
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SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_SETTINGS, frag_spec);
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#else
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SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_SIZE,
frag_spec & 0xffff);
SDL_NAME(arts_stream_set) (stream, ARTS_P_PACKET_COUNT, frag_spec >> 16);
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#endif
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spec->size = SDL_NAME(arts_stream_get) (stream, ARTS_P_PACKET_SIZE);
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/* Allocate mixing buffer */
mixlen = spec->size;
mixbuf = (Uint8 *) SDL_AllocAudioMem(mixlen);
if (mixbuf == NULL) {
return (-1);
}
SDL_memset(mixbuf, spec->silence, spec->size);
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/* Get the parent process id (we're the parent of the audio thread) */
parent = getpid();
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/* We're ready to rock and roll. :-) */
return (0);
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}
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/* vi: set ts=4 sw=4 expandtab: */