SDL-mirror/src/audio/disk/SDL_diskaudio.c

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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 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 hacked^H^H^H^H^H^Hwritten by Ryan C. Gordon
(icculus@linuxgames.com)
*/
/* Output raw audio data to a file. */
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "SDL_stdlib.h"
#include "SDL_string.h"
#include "SDL_audio.h"
#include "SDL_error.h"
#include "SDL_audiomem.h"
#include "SDL_audio_c.h"
#include "SDL_timer.h"
#include "SDL_audiodev_c.h"
#include "SDL_diskaudio.h"
/* The tag name used by DISK audio */
#define DISKAUD_DRIVER_NAME "disk"
/* environment variables and defaults. */
#define DISKENVR_OUTFILE "SDL_DISKAUDIOFILE"
#define DISKDEFAULT_OUTFILE "sdlaudio.raw"
#define DISKENVR_WRITEDELAY "SDL_DISKAUDIODELAY"
#define DISKDEFAULT_WRITEDELAY 150
/* Audio driver functions */
static int DISKAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);
static void DISKAUD_WaitAudio(_THIS);
static void DISKAUD_PlayAudio(_THIS);
static Uint8 *DISKAUD_GetAudioBuf(_THIS);
static void DISKAUD_CloseAudio(_THIS);
static const char *DISKAUD_GetOutputFilename(void)
{
const char *envr = SDL_getenv(DISKENVR_OUTFILE);
return((envr != NULL) ? envr : DISKDEFAULT_OUTFILE);
}
/* Audio driver bootstrap functions */
static int DISKAUD_Available(void)
{
#if 0
int fd;
int available;
int exists = 0;
struct stat statbuf;
const char *fname = DISKAUD_GetOutputFilename();
const char *envr = SDL_getenv("SDL_AUDIODRIVER");
available = 0;
if ((envr) && (SDL_strcmp(envr, DISKAUD_DRIVER_NAME) == 0)) {
if (stat(fname, &statbuf) == 0)
exists = 1;
fd = open(fname, O_WRONLY | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
if ( fd != -1 ) {
available = 1;
close(fd);
if (!exists) {
unlink(fname);
}
}
}
return(available);
#else
const char *envr = SDL_getenv("SDL_AUDIODRIVER");
if ((envr) && (SDL_strcmp(envr, DISKAUD_DRIVER_NAME) == 0)) {
return(1);
}
return(0);
#endif
}
static void DISKAUD_DeleteDevice(SDL_AudioDevice *device)
{
SDL_free(device->hidden);
SDL_free(device);
}
static SDL_AudioDevice *DISKAUD_CreateDevice(int devindex)
{
SDL_AudioDevice *this;
const char *envr;
/* 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));
envr = SDL_getenv(DISKENVR_WRITEDELAY);
this->hidden->write_delay = (envr) ? atoi(envr) : DISKDEFAULT_WRITEDELAY;
/* Set the function pointers */
this->OpenAudio = DISKAUD_OpenAudio;
this->WaitAudio = DISKAUD_WaitAudio;
this->PlayAudio = DISKAUD_PlayAudio;
this->GetAudioBuf = DISKAUD_GetAudioBuf;
this->CloseAudio = DISKAUD_CloseAudio;
this->free = DISKAUD_DeleteDevice;
return this;
}
AudioBootStrap DISKAUD_bootstrap = {
DISKAUD_DRIVER_NAME, "direct-to-disk audio",
DISKAUD_Available, DISKAUD_CreateDevice
};
/* This function waits until it is possible to write a full sound buffer */
static void DISKAUD_WaitAudio(_THIS)
{
SDL_Delay(this->hidden->write_delay);
}
static void DISKAUD_PlayAudio(_THIS)
{
int written;
/* Write the audio data, checking for EAGAIN on broken audio drivers */
do {
written = write(this->hidden->audio_fd,
this->hidden->mixbuf,
this->hidden->mixlen);
if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) {
SDL_Delay(1); /* Let a little CPU time go by */
}
} while ( (written < 0) &&
((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) );
/* If we couldn't write, assume fatal error for now */
if ( written < 0 ) {
this->enabled = 0;
}
#ifdef DEBUG_AUDIO
fprintf(stderr, "Wrote %d bytes of audio data\n", written);
#endif
}
static Uint8 *DISKAUD_GetAudioBuf(_THIS)
{
return(this->hidden->mixbuf);
}
static void DISKAUD_CloseAudio(_THIS)
{
if ( this->hidden->mixbuf != NULL ) {
SDL_FreeAudioMem(this->hidden->mixbuf);
this->hidden->mixbuf = NULL;
}
if ( this->hidden->audio_fd >= 0 ) {
close(this->hidden->audio_fd);
this->hidden->audio_fd = -1;
}
}
static int DISKAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
const char *fname = DISKAUD_GetOutputFilename();
/* Open the audio device */
this->hidden->audio_fd = open(fname, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
if ( this->hidden->audio_fd < 0 ) {
SDL_SetError("Couldn't open %s: %s", fname, strerror(errno));
return(-1);
}
fprintf(stderr, "WARNING: You are using the SDL disk writer"
" audio driver!\n Writing to file [%s].\n", fname);
/* 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);
/* We're ready to rock and roll. :-) */
return(0);
}