SDL  2.0
SDL_diskaudio.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../../SDL_internal.h"
22 
23 #if SDL_AUDIO_DRIVER_DISK
24 
25 /* Output raw audio data to a file. */
26 
27 #if HAVE_STDIO_H
28 #include <stdio.h>
29 #endif
30 
31 #include "SDL_rwops.h"
32 #include "SDL_timer.h"
33 #include "SDL_audio.h"
34 #include "../SDL_audio_c.h"
35 #include "SDL_diskaudio.h"
36 #include "SDL_log.h"
37 
38 /* !!! FIXME: these should be SDL hints, not environment variables. */
39 /* environment variables and defaults. */
40 #define DISKENVR_OUTFILE "SDL_DISKAUDIOFILE"
41 #define DISKDEFAULT_OUTFILE "sdlaudio.raw"
42 #define DISKENVR_INFILE "SDL_DISKAUDIOFILEIN"
43 #define DISKDEFAULT_INFILE "sdlaudio-in.raw"
44 #define DISKENVR_IODELAY "SDL_DISKAUDIODELAY"
45 
46 /* This function waits until it is possible to write a full sound buffer */
47 static void
48 DISKAUDIO_WaitDevice(_THIS)
49 {
50  SDL_Delay(this->hidden->io_delay);
51 }
52 
53 static void
54 DISKAUDIO_PlayDevice(_THIS)
55 {
56  const size_t written = SDL_RWwrite(this->hidden->io,
57  this->hidden->mixbuf,
58  1, this->spec.size);
59 
60  /* If we couldn't write, assume fatal error for now */
61  if (written != this->spec.size) {
63  }
64 #ifdef DEBUG_AUDIO
65  fprintf(stderr, "Wrote %d bytes of audio data\n", written);
66 #endif
67 }
68 
69 static Uint8 *
70 DISKAUDIO_GetDeviceBuf(_THIS)
71 {
72  return (this->hidden->mixbuf);
73 }
74 
75 static int
76 DISKAUDIO_CaptureFromDevice(_THIS, void *buffer, int buflen)
77 {
78  struct SDL_PrivateAudioData *h = this->hidden;
79  const int origbuflen = buflen;
80 
81  SDL_Delay(h->io_delay);
82 
83  if (h->io) {
84  const size_t br = SDL_RWread(h->io, buffer, 1, buflen);
85  buflen -= (int) br;
86  buffer = ((Uint8 *) buffer) + br;
87  if (buflen > 0) { /* EOF (or error, but whatever). */
88  SDL_RWclose(h->io);
89  h->io = NULL;
90  }
91  }
92 
93  /* if we ran out of file, just write silence. */
94  SDL_memset(buffer, this->spec.silence, buflen);
95 
96  return origbuflen;
97 }
98 
99 static void
100 DISKAUDIO_FlushCapture(_THIS)
101 {
102  /* no op...we don't advance the file pointer or anything. */
103 }
104 
105 
106 static void
107 DISKAUDIO_CloseDevice(_THIS)
108 {
109  if (this->hidden->io != NULL) {
110  SDL_RWclose(this->hidden->io);
111  }
112  SDL_free(this->hidden->mixbuf);
113  SDL_free(this->hidden);
114 }
115 
116 
117 static const char *
118 get_filename(const int iscapture, const char *devname)
119 {
120  if (devname == NULL) {
121  devname = SDL_getenv(iscapture ? DISKENVR_INFILE : DISKENVR_OUTFILE);
122  if (devname == NULL) {
123  devname = iscapture ? DISKDEFAULT_INFILE : DISKDEFAULT_OUTFILE;
124  }
125  }
126  return devname;
127 }
128 
129 static int
130 DISKAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
131 {
132  /* handle != NULL means "user specified the placeholder name on the fake detected device list" */
133  const char *fname = get_filename(iscapture, handle ? NULL : devname);
134  const char *envr = SDL_getenv(DISKENVR_IODELAY);
135 
136  this->hidden = (struct SDL_PrivateAudioData *)
137  SDL_malloc(sizeof(*this->hidden));
138  if (this->hidden == NULL) {
139  return SDL_OutOfMemory();
140  }
141  SDL_zerop(this->hidden);
142 
143  if (envr != NULL) {
144  this->hidden->io_delay = SDL_atoi(envr);
145  } else {
146  this->hidden->io_delay = ((this->spec.samples * 1000) / this->spec.freq);
147  }
148 
149  /* Open the audio device */
150  this->hidden->io = SDL_RWFromFile(fname, iscapture ? "rb" : "wb");
151  if (this->hidden->io == NULL) {
152  return -1;
153  }
154 
155  /* Allocate mixing buffer */
156  if (!iscapture) {
157  this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->spec.size);
158  if (this->hidden->mixbuf == NULL) {
159  return SDL_OutOfMemory();
160  }
161  SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
162  }
163 
165  "You are using the SDL disk i/o audio driver!\n");
167  " %s file [%s].\n", iscapture ? "Reading from" : "Writing to",
168  fname);
169 
170  /* We're ready to rock and roll. :-) */
171  return 0;
172 }
173 
174 static void
175 DISKAUDIO_DetectDevices(void)
176 {
179 }
180 
181 static int
182 DISKAUDIO_Init(SDL_AudioDriverImpl * impl)
183 {
184  /* Set the function pointers */
185  impl->OpenDevice = DISKAUDIO_OpenDevice;
186  impl->WaitDevice = DISKAUDIO_WaitDevice;
187  impl->PlayDevice = DISKAUDIO_PlayDevice;
188  impl->GetDeviceBuf = DISKAUDIO_GetDeviceBuf;
189  impl->CaptureFromDevice = DISKAUDIO_CaptureFromDevice;
190  impl->FlushCapture = DISKAUDIO_FlushCapture;
191 
192  impl->CloseDevice = DISKAUDIO_CloseDevice;
193  impl->DetectDevices = DISKAUDIO_DetectDevices;
194 
195  impl->AllowsArbitraryDeviceNames = 1;
196  impl->HasCaptureSupport = SDL_TRUE;
197 
198  return 1; /* this audio target is available. */
199 }
200 
202  "disk", "direct-to-disk audio", DISKAUDIO_Init, 1
203 };
204 
205 #endif /* SDL_AUDIO_DRIVER_DISK */
206 
207 /* vi: set ts=4 sw=4 expandtab: */
GLuint GLfloat GLfloat GLfloat x1
#define SDL_LogCritical
void(* DetectDevices)(void)
Definition: SDL_sysaudio.h:67
Uint8 silence
Definition: SDL_audio.h:182
#define SDL_RWwrite(ctx, ptr, size, n)
Definition: SDL_rwops.h:188
GLfloat GLfloat GLfloat GLfloat h
AudioBootStrap DISKAUDIO_bootstrap
#define SDL_RWread(ctx, ptr, size, n)
Definition: SDL_rwops.h:187
void(* PlayDevice)(_THIS)
Definition: SDL_sysaudio.h:73
Uint16 samples
Definition: SDL_audio.h:183
void(* WaitDevice)(_THIS)
Definition: SDL_sysaudio.h:72
void SDL_OpenedAudioDeviceDisconnected(SDL_AudioDevice *device)
Definition: SDL_audio.c:449
#define SDL_zerop(x)
Definition: SDL_stdinc.h:417
GLfixed GLfixed x2
SDL_AudioSpec spec
Definition: loopwave.c:31
#define SDL_RWFromFile
EGLImageKHR EGLint EGLint * handle
Definition: eglext.h:937
#define _THIS
uint8_t Uint8
Definition: SDL_stdinc.h:157
#define SDL_free
#define SDL_atoi
#define SDL_Delay
#define SDL_getenv
Uint32 size
Definition: SDL_audio.h:185
int(* OpenDevice)(_THIS, void *handle, const char *devname, int iscapture)
Definition: SDL_sysaudio.h:68
#define NULL
Definition: begin_code.h:164
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
GLuint buffer
int(* CaptureFromDevice)(_THIS, void *buffer, int buflen)
Definition: SDL_sysaudio.h:76
#define SDL_RWclose(ctx)
Definition: SDL_rwops.h:189
void(* CloseDevice)(_THIS)
Definition: SDL_sysaudio.h:79
void(* FlushCapture)(_THIS)
Definition: SDL_sysaudio.h:77
Uint8 *(* GetDeviceBuf)(_THIS)
Definition: SDL_sysaudio.h:75
#define DEFAULT_OUTPUT_DEVNAME
Definition: SDL_sysaudio.h:32
#define DEFAULT_INPUT_DEVNAME
Definition: SDL_sysaudio.h:33
#define SDL_malloc
#define SDL_memset
void SDL_AddAudioDevice(const int iscapture, const char *name, void *handle)
Definition: SDL_audio.c:432