SDL_diskaudio.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2009 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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This file written by Ryan C. Gordon (icculus@icculus.org)
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#include "SDL_config.h"
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/* Output raw audio data to a file. */
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#if HAVE_STDIO_H
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#include <stdio.h>
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#include "SDL_rwops.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_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)
{
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const char *envr = SDL_getenv(DISKENVR_OUTFILE);
return((envr != NULL) ? envr : DISKDEFAULT_OUTFILE);
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}
/* Audio driver bootstrap functions */
static int DISKAUD_Available(void)
{
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const char *envr = SDL_getenv("SDL_AUDIODRIVER");
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if (envr && (SDL_strcmp(envr, DISKAUD_DRIVER_NAME) == 0)) {
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return(1);
}
return(0);
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}
static void DISKAUD_DeleteDevice(SDL_AudioDevice *device)
{
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SDL_free(device->hidden);
SDL_free(device);
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}
static SDL_AudioDevice *DISKAUD_CreateDevice(int devindex)
{
SDL_AudioDevice *this;
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const char *envr;
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/* Initialize all variables that we clean on shutdown */
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this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
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if ( this ) {
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SDL_memset(this, 0, (sizeof *this));
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this->hidden = (struct SDL_PrivateAudioData *)
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SDL_malloc((sizeof *this->hidden));
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}
if ( (this == NULL) || (this->hidden == NULL) ) {
SDL_OutOfMemory();
if ( this ) {
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SDL_free(this);
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}
return(0);
}
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SDL_memset(this->hidden, 0, (sizeof *this->hidden));
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envr = SDL_getenv(DISKENVR_WRITEDELAY);
this->hidden->write_delay = (envr) ? SDL_atoi(envr) : DISKDEFAULT_WRITEDELAY;
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/* 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)
{
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SDL_Delay(this->hidden->write_delay);
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}
static void DISKAUD_PlayAudio(_THIS)
{
int written;
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/* Write the audio data */
written = SDL_RWwrite(this->hidden->output,
this->hidden->mixbuf, 1,
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this->hidden->mixlen);
/* If we couldn't write, assume fatal error for now */
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if ( (Uint32)written != this->hidden->mixlen ) {
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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;
}
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if ( this->hidden->output != NULL ) {
SDL_RWclose(this->hidden->output);
this->hidden->output = NULL;
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}
}
static int DISKAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
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const char *fname = DISKAUD_GetOutputFilename();
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/* Open the audio device */
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this->hidden->output = SDL_RWFromFile(fname, "wb");
if ( this->hidden->output == NULL ) {
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return(-1);
}
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#if HAVE_STDIO_H
fprintf(stderr, "WARNING: You are using the SDL disk writer"
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" audio driver!\n Writing to file [%s].\n", fname);
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/* Allocate mixing buffer */
this->hidden->mixlen = spec->size;
this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
if ( this->hidden->mixbuf == NULL ) {
return(-1);
}
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SDL_memset(this->hidden->mixbuf, spec->silence, spec->size);
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/* We're ready to rock and roll. :-) */
return(0);
}