/external/qemu/distrib/sdl-1.2.15/src/audio/dsp/SDL_dspaudio.c
C | 340 lines | 249 code | 37 blank | 54 comment | 41 complexity | 9814c68fd01f464a95710e2ebd35a6cf MD5 | raw file
- /*
- 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
- Modified in Oct 2004 by Hannu Savolainen
- hannu@opensound.com
- */
- #include "SDL_config.h"
- /* Allow access to a raw mixing buffer */
- #include <stdio.h> /* For perror() */
- #include <string.h> /* For strerror() */
- #include <errno.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include <signal.h>
- #include <sys/time.h>
- #include <sys/ioctl.h>
- #include <sys/stat.h>
- #if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H
- /* This is installed on some systems */
- #include <soundcard.h>
- #else
- /* This is recommended by OSS */
- #include <sys/soundcard.h>
- #endif
- #include "SDL_timer.h"
- #include "SDL_audio.h"
- #include "../SDL_audiomem.h"
- #include "../SDL_audio_c.h"
- #include "../SDL_audiodev_c.h"
- #include "SDL_dspaudio.h"
- /* The tag name used by DSP audio */
- #define DSP_DRIVER_NAME "dsp"
- /* Open the audio device for playback, and don't block if busy */
- #define OPEN_FLAGS (O_WRONLY|O_NONBLOCK)
- /* Audio driver functions */
- static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec);
- static void DSP_WaitAudio(_THIS);
- static void DSP_PlayAudio(_THIS);
- static Uint8 *DSP_GetAudioBuf(_THIS);
- static void DSP_CloseAudio(_THIS);
- /* Audio driver bootstrap functions */
- static int Audio_Available(void)
- {
- int fd;
- int available;
- available = 0;
- fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
- if ( fd >= 0 ) {
- available = 1;
- close(fd);
- }
- return(available);
- }
- static void Audio_DeleteDevice(SDL_AudioDevice *device)
- {
- SDL_free(device->hidden);
- SDL_free(device);
- }
- static SDL_AudioDevice *Audio_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));
- audio_fd = -1;
- /* Set the function pointers */
- this->OpenAudio = DSP_OpenAudio;
- this->WaitAudio = DSP_WaitAudio;
- this->PlayAudio = DSP_PlayAudio;
- this->GetAudioBuf = DSP_GetAudioBuf;
- this->CloseAudio = DSP_CloseAudio;
- this->free = Audio_DeleteDevice;
- return this;
- }
- AudioBootStrap DSP_bootstrap = {
- DSP_DRIVER_NAME, "OSS /dev/dsp standard audio",
- Audio_Available, Audio_CreateDevice
- };
- /* This function waits until it is possible to write a full sound buffer */
- static void DSP_WaitAudio(_THIS)
- {
- /* Not needed at all since OSS handles waiting automagically */
- }
- static void DSP_PlayAudio(_THIS)
- {
- if (write(audio_fd, mixbuf, mixlen)==-1)
- {
- perror("Audio write");
- this->enabled = 0;
- }
- #ifdef DEBUG_AUDIO
- fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen);
- #endif
- }
- static Uint8 *DSP_GetAudioBuf(_THIS)
- {
- return(mixbuf);
- }
- static void DSP_CloseAudio(_THIS)
- {
- if ( mixbuf != NULL ) {
- SDL_FreeAudioMem(mixbuf);
- mixbuf = NULL;
- }
- if ( audio_fd >= 0 ) {
- close(audio_fd);
- audio_fd = -1;
- }
- }
- static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec)
- {
- char audiodev[1024];
- int format;
- int value;
- int frag_spec;
- Uint16 test_format;
- /* Make sure fragment size stays a power of 2, or OSS fails. */
- /* I don't know which of these are actually legal values, though... */
- if (spec->channels > 8)
- spec->channels = 8;
- else if (spec->channels > 4)
- spec->channels = 4;
- else if (spec->channels > 2)
- spec->channels = 2;
- /* Open the audio device */
- audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
- if ( audio_fd < 0 ) {
- SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
- return(-1);
- }
- mixbuf = NULL;
- /* Make the file descriptor use blocking writes with fcntl() */
- { long flags;
- flags = fcntl(audio_fd, F_GETFL);
- flags &= ~O_NONBLOCK;
- if ( fcntl(audio_fd, F_SETFL, flags) < 0 ) {
- SDL_SetError("Couldn't set audio blocking mode");
- DSP_CloseAudio(this);
- return(-1);
- }
- }
- /* Get a list of supported hardware formats */
- if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
- perror("SNDCTL_DSP_GETFMTS");
- SDL_SetError("Couldn't get audio format list");
- DSP_CloseAudio(this);
- return(-1);
- }
- /* Try for a closest match on audio format */
- format = 0;
- for ( test_format = SDL_FirstAudioFormat(spec->format);
- ! format && test_format; ) {
- #ifdef DEBUG_AUDIO
- fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
- #endif
- switch ( test_format ) {
- case AUDIO_U8:
- if ( value & AFMT_U8 ) {
- format = AFMT_U8;
- }
- break;
- case AUDIO_S16LSB:
- if ( value & AFMT_S16_LE ) {
- format = AFMT_S16_LE;
- }
- break;
- case AUDIO_S16MSB:
- if ( value & AFMT_S16_BE ) {
- format = AFMT_S16_BE;
- }
- break;
- #if 0
- /*
- * These formats are not used by any real life systems so they are not
- * needed here.
- */
- case AUDIO_S8:
- if ( value & AFMT_S8 ) {
- format = AFMT_S8;
- }
- break;
- case AUDIO_U16LSB:
- if ( value & AFMT_U16_LE ) {
- format = AFMT_U16_LE;
- }
- break;
- case AUDIO_U16MSB:
- if ( value & AFMT_U16_BE ) {
- format = AFMT_U16_BE;
- }
- break;
- #endif
- default:
- format = 0;
- break;
- }
- if ( ! format ) {
- test_format = SDL_NextAudioFormat();
- }
- }
- if ( format == 0 ) {
- SDL_SetError("Couldn't find any hardware audio formats");
- DSP_CloseAudio(this);
- return(-1);
- }
- spec->format = test_format;
- /* Set the audio format */
- value = format;
- if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
- (value != format) ) {
- perror("SNDCTL_DSP_SETFMT");
- SDL_SetError("Couldn't set audio format");
- DSP_CloseAudio(this);
- return(-1);
- }
- /* Set the number of channels of output */
- value = spec->channels;
- if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) {
- perror("SNDCTL_DSP_CHANNELS");
- SDL_SetError("Cannot set the number of channels");
- DSP_CloseAudio(this);
- return(-1);
- }
- spec->channels = value;
- /* Set the DSP frequency */
- value = spec->freq;
- if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) {
- perror("SNDCTL_DSP_SPEED");
- SDL_SetError("Couldn't set audio frequency");
- DSP_CloseAudio(this);
- return(-1);
- }
- spec->freq = value;
- /* Calculate the final parameters for this audio specification */
- SDL_CalculateAudioSpec(spec);
- /* Determine the power of two of the fragment size */
- for ( frag_spec = 0; (0x01U<<frag_spec) < spec->size; ++frag_spec );
- if ( (0x01U<<frag_spec) != spec->size ) {
- SDL_SetError("Fragment size must be a power of two");
- DSP_CloseAudio(this);
- return(-1);
- }
- frag_spec |= 0x00020000; /* two fragments, for low latency */
- /* Set the audio buffering parameters */
- #ifdef DEBUG_AUDIO
- fprintf(stderr, "Requesting %d fragments of size %d\n",
- (frag_spec >> 16), 1<<(frag_spec&0xFFFF));
- #endif
- if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
- perror("SNDCTL_DSP_SETFRAGMENT");
- }
- #ifdef DEBUG_AUDIO
- { audio_buf_info info;
- ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info);
- fprintf(stderr, "fragments = %d\n", info.fragments);
- fprintf(stderr, "fragstotal = %d\n", info.fragstotal);
- fprintf(stderr, "fragsize = %d\n", info.fragsize);
- fprintf(stderr, "bytes = %d\n", info.bytes);
- }
- #endif
- /* Allocate mixing buffer */
- mixlen = spec->size;
- mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
- if ( mixbuf == NULL ) {
- DSP_CloseAudio(this);
- return(-1);
- }
- SDL_memset(mixbuf, spec->silence, spec->size);
- /* Get the parent process id (we're the parent of the audio thread) */
- parent = getpid();
- /* We're ready to rock and roll. :-) */
- return(0);
- }