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Diffstat (limited to 'apps/plugins/sdl/src/audio/dummy/SDL_dummyaudio.c')
-rw-r--r--apps/plugins/sdl/src/audio/dummy/SDL_dummyaudio.c156
1 files changed, 156 insertions, 0 deletions
diff --git a/apps/plugins/sdl/src/audio/dummy/SDL_dummyaudio.c b/apps/plugins/sdl/src/audio/dummy/SDL_dummyaudio.c
new file mode 100644
index 0000000000..484b50d40c
--- /dev/null
+++ b/apps/plugins/sdl/src/audio/dummy/SDL_dummyaudio.c
@@ -0,0 +1,156 @@
+/*
+ SDL - Simple DirectMedia Layer
+ Copyright (C) 1997-2012 Sam Lantinga
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ 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
+ Lesser General Public License for more details.
+
+ 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
+
+ Sam Lantinga
+ slouken@libsdl.org
+
+ This file written by Ryan C. Gordon (icculus@icculus.org)
+*/
+#include "SDL_config.h"
+
+/* Output audio to nowhere... */
+
+#include "SDL_rwops.h"
+#include "SDL_timer.h"
+#include "SDL_audio.h"
+#include "../SDL_audiomem.h"
+#include "../SDL_audio_c.h"
+#include "../SDL_audiodev_c.h"
+#include "SDL_dummyaudio.h"
+
+/* The tag name used by DUMMY audio */
+#define DUMMYAUD_DRIVER_NAME "dummy"
+
+/* Audio driver functions */
+static int DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);
+static void DUMMYAUD_WaitAudio(_THIS);
+static void DUMMYAUD_PlayAudio(_THIS);
+static Uint8 *DUMMYAUD_GetAudioBuf(_THIS);
+static void DUMMYAUD_CloseAudio(_THIS);
+
+/* Audio driver bootstrap functions */
+static int DUMMYAUD_Available(void)
+{
+ const char *envr = SDL_getenv("SDL_AUDIODRIVER");
+ if (envr && (SDL_strcmp(envr, DUMMYAUD_DRIVER_NAME) == 0)) {
+ return(1);
+ }
+ return(0);
+}
+
+static void DUMMYAUD_DeleteDevice(SDL_AudioDevice *device)
+{
+ SDL_free(device->hidden);
+ SDL_free(device);
+}
+
+static SDL_AudioDevice *DUMMYAUD_CreateDevice(int devindex)
+{
+ SDL_AudioDevice *this;
+
+ /* Initialize all variables that we clean on shutdown */
+ 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));
+
+ /* Set the function pointers */
+ this->OpenAudio = DUMMYAUD_OpenAudio;
+ this->WaitAudio = DUMMYAUD_WaitAudio;
+ this->PlayAudio = DUMMYAUD_PlayAudio;
+ this->GetAudioBuf = DUMMYAUD_GetAudioBuf;
+ this->CloseAudio = DUMMYAUD_CloseAudio;
+
+ this->free = DUMMYAUD_DeleteDevice;
+
+ return this;
+}
+
+AudioBootStrap DUMMYAUD_bootstrap = {
+ DUMMYAUD_DRIVER_NAME, "SDL dummy audio driver",
+ DUMMYAUD_Available, DUMMYAUD_CreateDevice
+};
+
+/* This function waits until it is possible to write a full sound buffer */
+static void DUMMYAUD_WaitAudio(_THIS)
+{
+ /* Don't block on first calls to simulate initial fragment filling. */
+ if (this->hidden->initial_calls)
+ this->hidden->initial_calls--;
+ else
+ SDL_Delay(this->hidden->write_delay);
+}
+
+static void DUMMYAUD_PlayAudio(_THIS)
+{
+ /* no-op...this is a null driver. */
+}
+
+static Uint8 *DUMMYAUD_GetAudioBuf(_THIS)
+{
+ return(this->hidden->mixbuf);
+}
+
+static void DUMMYAUD_CloseAudio(_THIS)
+{
+ if ( this->hidden->mixbuf != NULL ) {
+ SDL_FreeAudioMem(this->hidden->mixbuf);
+ this->hidden->mixbuf = NULL;
+ }
+}
+
+static int DUMMYAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
+{
+ float bytes_per_sec = 0.0f;
+
+ /* Allocate mixing buffer */
+ this->hidden->mixlen = spec->size;
+ this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
+ if ( this->hidden->mixbuf == NULL ) {
+ return(-1);
+ }
+ SDL_memset(this->hidden->mixbuf, spec->silence, spec->size);
+
+ bytes_per_sec = (float) (((spec->format & 0xFF) / 8) *
+ spec->channels * spec->freq);
+
+ /*
+ * We try to make this request more audio at the correct rate for
+ * a given audio spec, so timing stays fairly faithful.
+ * Also, we have it not block at all for the first two calls, so
+ * it seems like we're filling two audio fragments right out of the
+ * gate, like other SDL drivers tend to do.
+ */
+ this->hidden->initial_calls = 2;
+ this->hidden->write_delay =
+ (Uint32) ((((float) spec->size) / bytes_per_sec) * 1000.0f);
+
+ /* We're ready to rock and roll. :-) */
+ return(0);
+}
+