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SDL_sunaudio.c
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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 */
#include <fcntl.h>
#include <errno.h>
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#ifdef __NETBSD__
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#include <sys/ioctl.h>
#include <sys/audioio.h>
#endif
#ifdef __SVR4
#include <sys/audioio.h>
#else
#include <sys/time.h>
#include <sys/types.h>
#endif
#include <unistd.h>
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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_sunaudio.h"
/* Open the audio device for playback, and don't block if busy */
#define OPEN_FLAGS (O_WRONLY|O_NONBLOCK)
/* Audio driver functions */
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static int DSP_OpenAudio(_THIS, SDL_AudioSpec * spec);
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static void DSP_WaitAudio(_THIS);
static void DSP_PlayAudio(_THIS);
static Uint8 *DSP_GetAudioBuf(_THIS);
static void DSP_CloseAudio(_THIS);
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static Uint8 snd2au(int sample);
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/* Audio driver bootstrap functions */
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static int
Audio_Available(void)
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int fd;
int available;
available = 0;
fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 1);
if (fd >= 0) {
available = 1;
close(fd);
}
return (available);
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}
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static void
Audio_DeleteDevice(SDL_AudioDevice * device)
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SDL_free(device->hidden);
SDL_free(device);
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}
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static SDL_AudioDevice *
Audio_CreateDevice(int devindex)
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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;
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}
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AudioBootStrap SUNAUDIO_bootstrap = {
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"audio", "UNIX /dev/audio interface",
Audio_Available, Audio_CreateDevice
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};
#ifdef DEBUG_AUDIO
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void
CheckUnderflow(_THIS)
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{
#ifdef AUDIO_GETINFO
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audio_info_t info;
int left;
ioctl(audio_fd, AUDIO_GETINFO, &info);
left = (written - info.play.samples);
if (written && (left == 0)) {
fprintf(stderr, "audio underflow!\n");
}
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#endif
}
#endif
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void
DSP_WaitAudio(_THIS)
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{
#ifdef AUDIO_GETINFO
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#define SLEEP_FUDGE 10 /* 10 ms scheduling fudge factor */
audio_info_t info;
Sint32 left;
ioctl(audio_fd, AUDIO_GETINFO, &info);
left = (written - info.play.samples);
if (left > fragsize) {
Sint32 sleepy;
sleepy = ((left - fragsize) / frequency);
sleepy -= SLEEP_FUDGE;
if (sleepy > 0) {
SDL_Delay(sleepy);
}
}
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#else
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fd_set fdset;
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FD_ZERO(&fdset);
FD_SET(audio_fd, &fdset);
select(audio_fd + 1, NULL, &fdset, NULL, NULL);
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#endif
}
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void
DSP_PlayAudio(_THIS)
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{
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/* Write the audio data */
if (ulaw_only) {
/* Assuming that this->spec.freq >= 8000 Hz */
int accum, incr, pos;
Uint8 *aubuf;
accum = 0;
incr = this->spec.freq / 8;
aubuf = ulaw_buf;
switch (audio_fmt & 0xFF) {
case 8:
{
Uint8 *sndbuf;
sndbuf = mixbuf;
for (pos = 0; pos < fragsize; ++pos) {
*aubuf = snd2au((0x80 - *sndbuf) * 64);
accum += incr;
while (accum > 0) {
accum -= 1000;
sndbuf += 1;
}
aubuf += 1;
}
}
break;
case 16:
{
Sint16 *sndbuf;
sndbuf = (Sint16 *) mixbuf;
for (pos = 0; pos < fragsize; ++pos) {
*aubuf = snd2au(*sndbuf / 4);
accum += incr;
while (accum > 0) {
accum -= 1000;
sndbuf += 1;
}
aubuf += 1;
}
}
break;
}
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#ifdef DEBUG_AUDIO
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CheckUnderflow(this);
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#endif
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if (write(audio_fd, ulaw_buf, fragsize) < 0) {
/* Assume fatal error, for now */
this->enabled = 0;
}
written += fragsize;
} else {
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#ifdef DEBUG_AUDIO
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CheckUnderflow(this);
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#endif
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if (write(audio_fd, mixbuf, this->spec.size) < 0) {
/* Assume fatal error, for now */
this->enabled = 0;
}
written += fragsize;
}
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}
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Uint8 *
DSP_GetAudioBuf(_THIS)
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{
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return (mixbuf);
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}
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void
DSP_CloseAudio(_THIS)
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{
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if (mixbuf != NULL) {
SDL_FreeAudioMem(mixbuf);
mixbuf = NULL;
}
if (ulaw_buf != NULL) {
SDL_free(ulaw_buf);
ulaw_buf = NULL;
}
close(audio_fd);
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}
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int
DSP_OpenAudio(_THIS, SDL_AudioSpec * spec)
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{
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char audiodev[1024];
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#ifdef AUDIO_SETINFO
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#endif
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int desired_freq = spec->freq;
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/* Initialize our freeable variables, in case we fail */
audio_fd = -1;
mixbuf = NULL;
ulaw_buf = NULL;
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/* Determine the audio parameters from the AudioSpec */
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switch (SDL_AUDIO_BITSIZE(spec->format)) {
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case 8:
{ /* Unsigned 8 bit audio data */
spec->format = AUDIO_U8;
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#ifdef AUDIO_SETINFO
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enc = AUDIO_ENCODING_LINEAR8;
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#endif
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case 16:
{ /* Signed 16 bit audio data */
spec->format = AUDIO_S16SYS;
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#ifdef AUDIO_SETINFO
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enc = AUDIO_ENCODING_LINEAR;
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#endif
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}
break;
default:
{
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/* !!! FIXME: fallback to conversion on unsupported types! */
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SDL_SetError("Unsupported audio format");
return (-1);
}
}
audio_fmt = spec->format;
/* Open the audio device */
audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 1);
if (audio_fd < 0) {
SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
return (-1);
}
ulaw_only = 0; /* modern Suns do support linear audio */
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#ifdef AUDIO_SETINFO
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for (;;) {
audio_info_t info;
AUDIO_INITINFO(&info); /* init all fields to "no change" */
/* Try to set the requested settings */
info.play.sample_rate = spec->freq;
info.play.channels = spec->channels;
info.play.precision = (enc == AUDIO_ENCODING_ULAW)
? 8 : spec->format & 0xff;
info.play.encoding = enc;
if (ioctl(audio_fd, AUDIO_SETINFO, &info) == 0) {
/* Check to be sure we got what we wanted */
if (ioctl(audio_fd, AUDIO_GETINFO, &info) < 0) {
SDL_SetError("Error getting audio parameters: %s",
strerror(errno));
return -1;
}
if (info.play.encoding == enc
&& info.play.precision == (spec->format & 0xff)
&& info.play.channels == spec->channels) {
/* Yow! All seems to be well! */
spec->freq = info.play.sample_rate;
break;
}
}
switch (enc) {
case AUDIO_ENCODING_LINEAR8:
/* unsigned 8bit apparently not supported here */
enc = AUDIO_ENCODING_LINEAR;
spec->format = AUDIO_S16SYS;
break; /* try again */
case AUDIO_ENCODING_LINEAR:
/* linear 16bit didn't work either, resort to µ-law */
enc = AUDIO_ENCODING_ULAW;
spec->channels = 1;
spec->freq = 8000;
spec->format = AUDIO_U8;
ulaw_only = 1;
break;
default:
/* oh well... */
SDL_SetError("Error setting audio parameters: %s",
strerror(errno));
return -1;
}
}
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#endif /* AUDIO_SETINFO */
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written = 0;
/* We can actually convert on-the-fly to U-Law */
if (ulaw_only) {
spec->freq = desired_freq;
fragsize = (spec->samples * 1000) / (spec->freq / 8);
frequency = 8;
ulaw_buf = (Uint8 *) SDL_malloc(fragsize);
if (ulaw_buf == NULL) {
SDL_OutOfMemory();
return (-1);
}
spec->channels = 1;
} else {
fragsize = spec->samples;
frequency = spec->freq / 1000;
}
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#ifdef DEBUG_AUDIO
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fprintf(stderr, "Audio device %s U-Law only\n",
ulaw_only ? "is" : "is not");
fprintf(stderr, "format=0x%x chan=%d freq=%d\n",
spec->format, spec->channels, spec->freq);
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#endif
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/* Update the fragment size as size in bytes */
SDL_CalculateAudioSpec(spec);
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/* Allocate mixing buffer */
mixbuf = (Uint8 *) SDL_AllocAudioMem(spec->size);
if (mixbuf == NULL) {
SDL_OutOfMemory();
return (-1);
}
SDL_memset(mixbuf, spec->silence, spec->size);
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/* We're ready to rock and roll. :-) */
return (0);
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}
/************************************************************************/
/* This function (snd2au()) copyrighted: */
/************************************************************************/
/* Copyright 1989 by Rich Gopstein and Harris Corporation */
/* */
/* Permission to use, copy, modify, and distribute this software */
/* and its documentation for any purpose and without fee is */
/* hereby granted, provided that the above copyright notice */
/* appears in all copies and that both that copyright notice and */
/* this permission notice appear in supporting documentation, and */
/* that the name of Rich Gopstein and Harris Corporation not be */
/* used in advertising or publicity pertaining to distribution */
/* of the software without specific, written prior permission. */
/* Rich Gopstein and Harris Corporation make no representations */
/* about the suitability of this software for any purpose. It */
/* provided "as is" without express or implied warranty. */
/************************************************************************/
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static Uint8
snd2au(int sample)
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{
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int mask;
if (sample < 0) {
sample = -sample;
mask = 0x7f;
} else {
mask = 0xff;
}
if (sample < 32) {
sample = 0xF0 | (15 - sample / 2);
} else if (sample < 96) {
sample = 0xE0 | (15 - (sample - 32) / 4);
} else if (sample < 224) {
sample = 0xD0 | (15 - (sample - 96) / 8);
} else if (sample < 480) {
sample = 0xC0 | (15 - (sample - 224) / 16);
} else if (sample < 992) {
sample = 0xB0 | (15 - (sample - 480) / 32);
} else if (sample < 2016) {
sample = 0xA0 | (15 - (sample - 992) / 64);
} else if (sample < 4064) {
sample = 0x90 | (15 - (sample - 2016) / 128);
} else if (sample < 8160) {
sample = 0x80 | (15 - (sample - 4064) / 256);
} else {
sample = 0x80;
}
return (mask & sample);
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}
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/* vi: set ts=4 sw=4 expandtab: */