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comparison src/audio/disk/SDL_diskaudio.c @ 68:ac6645260d31

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Added an audio driver that writes to disk (thanks Ryan!)
author Sam Lantinga <slouken@lokigames.com>
date Sat, 16 Jun 2001 01:51:42 +0000
parents
children 13e4c612098d
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67:3647c809813d 68:ac6645260d31
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21
22 This file hacked^H^H^H^H^H^Hwritten by Ryan C. Gordon
23 (icculus@linuxgames.com)
24 */
25
26 #ifdef SAVE_RCSID
27 static char rcsid =
28 "@(#) $Id$";
29 #endif
30
31 /* Output raw audio data to a file. */
32
33 #include <stdlib.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <errno.h>
37 #include <unistd.h>
38 #include <sys/stat.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42
43
44 #include "SDL_audio.h"
45 #include "SDL_error.h"
46 #include "SDL_audiomem.h"
47 #include "SDL_audio_c.h"
48 #include "SDL_timer.h"
49 #include "SDL_audiodev_c.h"
50 #include "SDL_diskaudio.h"
51
52 /* The tag name used by DISK audio */
53 #define DISKAUD_DRIVER_NAME "disk"
54
55 /* environment variables and defaults. */
56 #define DISKENVR_OUTFILE "SDL_DISKAUDIOFILE"
57 #define DISKDEFAULT_OUTFILE "sdlaudio.raw"
58 #define DISKENVR_WRITEDELAY "SDL_DISKAUDIODELAY"
59 #define DISKDEFAULT_WRITEDELAY 150
60
61 /* Audio driver functions */
62 static int DISKAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);
63 static void DISKAUD_WaitAudio(_THIS);
64 static void DISKAUD_PlayAudio(_THIS);
65 static Uint8 *DISKAUD_GetAudioBuf(_THIS);
66 static void DISKAUD_CloseAudio(_THIS);
67
68 static const char *DISKAUD_GetOutputFilename(void)
69 {
70 const char *envr = getenv(DISKENVR_OUTFILE);
71 return((envr != NULL) ? envr : DISKDEFAULT_OUTFILE);
72 }
73
74 /* Audio driver bootstrap functions */
75 static int DISKAUD_Available(void)
76 {
77 #if 0
78 int fd;
79 int available;
80 int exists = 0;
81 struct stat statbuf;
82 const char *fname = DISKAUD_GetOutputFilename();
83
84 available = 0;
85
86 if (stat(fname, &statbuf) == 0)
87 exists = 1;
88
89 fd = open(fname, O_WRONLY | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
90 if ( fd != -1 ) {
91 available = 1;
92 close(fd);
93 if (!exists) {
94 unlink(fname);
95 }
96 }
97 return(available);
98 #else
99 return(1);
100 #endif
101 }
102
103 static void DISKAUD_DeleteDevice(SDL_AudioDevice *device)
104 {
105 free(device->hidden);
106 free(device);
107 }
108
109 static SDL_AudioDevice *DISKAUD_CreateDevice(int devindex)
110 {
111 SDL_AudioDevice *this;
112 const char *envr;
113
114 /* Initialize all variables that we clean on shutdown */
115 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
116 if ( this ) {
117 memset(this, 0, (sizeof *this));
118 this->hidden = (struct SDL_PrivateAudioData *)
119 malloc((sizeof *this->hidden));
120 }
121 if ( (this == NULL) || (this->hidden == NULL) ) {
122 SDL_OutOfMemory();
123 if ( this ) {
124 free(this);
125 }
126 return(0);
127 }
128 memset(this->hidden, 0, (sizeof *this->hidden));
129
130 envr = getenv(DISKENVR_WRITEDELAY);
131 this->hidden->write_delay = (envr) ? atoi(envr) : DISKDEFAULT_WRITEDELAY;
132
133 /* Set the function pointers */
134 this->OpenAudio = DISKAUD_OpenAudio;
135 this->WaitAudio = DISKAUD_WaitAudio;
136 this->PlayAudio = DISKAUD_PlayAudio;
137 this->GetAudioBuf = DISKAUD_GetAudioBuf;
138 this->CloseAudio = DISKAUD_CloseAudio;
139
140 this->free = DISKAUD_DeleteDevice;
141
142 return this;
143 }
144
145 AudioBootStrap DISKAUD_bootstrap = {
146 DISKAUD_DRIVER_NAME, "direct-to-disk audio",
147 DISKAUD_Available, DISKAUD_CreateDevice
148 };
149
150 /* This function waits until it is possible to write a full sound buffer */
151 static void DISKAUD_WaitAudio(_THIS)
152 {
153 SDL_Delay(this->hidden->write_delay);
154 }
155
156 static void DISKAUD_PlayAudio(_THIS)
157 {
158 int written;
159
160 /* Write the audio data, checking for EAGAIN on broken audio drivers */
161 do {
162 written = write(this->hidden->audio_fd,
163 this->hidden->mixbuf,
164 this->hidden->mixlen);
165 if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) {
166 SDL_Delay(1); /* Let a little CPU time go by */
167 }
168 } while ( (written < 0) &&
169 ((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) );
170
171 /* If we couldn't write, assume fatal error for now */
172 if ( written < 0 ) {
173 this->enabled = 0;
174 }
175 #ifdef DEBUG_AUDIO
176 fprintf(stderr, "Wrote %d bytes of audio data\n", written);
177 #endif
178 }
179
180 static Uint8 *DISKAUD_GetAudioBuf(_THIS)
181 {
182 return(this->hidden->mixbuf);
183 }
184
185 static void DISKAUD_CloseAudio(_THIS)
186 {
187 if ( this->hidden->mixbuf != NULL ) {
188 SDL_FreeAudioMem(this->hidden->mixbuf);
189 this->hidden->mixbuf = NULL;
190 }
191 if ( this->hidden->audio_fd >= 0 ) {
192 close(this->hidden->audio_fd);
193 this->hidden->audio_fd = -1;
194 }
195 }
196
197 static int DISKAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
198 {
199 const char *fname = DISKAUD_GetOutputFilename();
200
201 /* Open the audio device */
202 this->hidden->audio_fd = open(fname, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
203 if ( this->hidden->audio_fd < 0 ) {
204 SDL_SetError("Couldn't open %s: %s", fname, strerror(errno));
205 return(-1);
206 }
207
208 fprintf(stderr, "WARNING: You are using the SDL disk writer"
209 " audio driver!\n Writing to file [%s].\n", fname);
210
211 /* Allocate mixing buffer */
212 this->hidden->mixlen = spec->size;
213 this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
214 if ( this->hidden->mixbuf == NULL ) {
215 return(-1);
216 }
217 memset(this->hidden->mixbuf, spec->silence, spec->size);
218
219 /* We're ready to rock and roll. :-) */
220 return(0);
221 }
222