src/audio/disk/SDL_diskaudio.c
author Sam Lantinga
Sat, 06 Oct 2012 11:23:47 -0700
changeset 6565 1f3c0df426dc
parent 6138 4c64952a58fb
child 6885 700f1b25f77f
permissions -rw-r--r--
When using Xinerama, XVidMode always works on screen 0. Otherwise use the real X11 screen.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2012 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_config.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_audiomem.h"
    35 #include "../SDL_audio_c.h"
    36 #include "SDL_diskaudio.h"
    37 
    38 /* environment variables and defaults. */
    39 #define DISKENVR_OUTFILE         "SDL_DISKAUDIOFILE"
    40 #define DISKDEFAULT_OUTFILE      "sdlaudio.raw"
    41 #define DISKENVR_WRITEDELAY      "SDL_DISKAUDIODELAY"
    42 #define DISKDEFAULT_WRITEDELAY   150
    43 
    44 static const char *
    45 DISKAUD_GetOutputFilename(const char *devname)
    46 {
    47     if (devname == NULL) {
    48         devname = SDL_getenv(DISKENVR_OUTFILE);
    49         if (devname == NULL) {
    50             devname = DISKDEFAULT_OUTFILE;
    51         }
    52     }
    53     return devname;
    54 }
    55 
    56 /* This function waits until it is possible to write a full sound buffer */
    57 static void
    58 DISKAUD_WaitDevice(_THIS)
    59 {
    60     SDL_Delay(this->hidden->write_delay);
    61 }
    62 
    63 static void
    64 DISKAUD_PlayDevice(_THIS)
    65 {
    66     size_t written;
    67 
    68     /* Write the audio data */
    69     written = SDL_RWwrite(this->hidden->output,
    70                           this->hidden->mixbuf, 1, this->hidden->mixlen);
    71 
    72     /* If we couldn't write, assume fatal error for now */
    73     if (written != this->hidden->mixlen) {
    74         this->enabled = 0;
    75     }
    76 #ifdef DEBUG_AUDIO
    77     fprintf(stderr, "Wrote %d bytes of audio data\n", written);
    78 #endif
    79 }
    80 
    81 static Uint8 *
    82 DISKAUD_GetDeviceBuf(_THIS)
    83 {
    84     return (this->hidden->mixbuf);
    85 }
    86 
    87 static void
    88 DISKAUD_CloseDevice(_THIS)
    89 {
    90     if (this->hidden != NULL) {
    91         if (this->hidden->mixbuf != NULL) {
    92             SDL_FreeAudioMem(this->hidden->mixbuf);
    93             this->hidden->mixbuf = NULL;
    94         }
    95         if (this->hidden->output != NULL) {
    96             SDL_RWclose(this->hidden->output);
    97             this->hidden->output = NULL;
    98         }
    99         SDL_free(this->hidden);
   100         this->hidden = NULL;
   101     }
   102 }
   103 
   104 static int
   105 DISKAUD_OpenDevice(_THIS, const char *devname, int iscapture)
   106 {
   107     const char *envr = SDL_getenv(DISKENVR_WRITEDELAY);
   108     const char *fname = DISKAUD_GetOutputFilename(devname);
   109 
   110     this->hidden = (struct SDL_PrivateAudioData *)
   111         SDL_malloc(sizeof(*this->hidden));
   112     if (this->hidden == NULL) {
   113         SDL_OutOfMemory();
   114         return 0;
   115     }
   116     SDL_memset(this->hidden, 0, sizeof(*this->hidden));
   117 
   118     /* Open the audio device */
   119     this->hidden->output = SDL_RWFromFile(fname, "wb");
   120     if (this->hidden->output == NULL) {
   121         DISKAUD_CloseDevice(this);
   122         return 0;
   123     }
   124 
   125     /* Allocate mixing buffer */
   126     this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
   127     if (this->hidden->mixbuf == NULL) {
   128         DISKAUD_CloseDevice(this);
   129         return 0;
   130     }
   131     SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
   132 
   133     this->hidden->mixlen = this->spec.size;
   134     this->hidden->write_delay =
   135         (envr) ? SDL_atoi(envr) : DISKDEFAULT_WRITEDELAY;
   136 
   137 #if HAVE_STDIO_H
   138     fprintf(stderr,
   139             "WARNING: You are using the SDL disk writer audio driver!\n"
   140             " Writing to file [%s].\n", fname);
   141 #endif
   142 
   143     /* We're ready to rock and roll. :-) */
   144     return 1;
   145 }
   146 
   147 static int
   148 DISKAUD_Init(SDL_AudioDriverImpl * impl)
   149 {
   150     /* Set the function pointers */
   151     impl->OpenDevice = DISKAUD_OpenDevice;
   152     impl->WaitDevice = DISKAUD_WaitDevice;
   153     impl->PlayDevice = DISKAUD_PlayDevice;
   154     impl->GetDeviceBuf = DISKAUD_GetDeviceBuf;
   155     impl->CloseDevice = DISKAUD_CloseDevice;
   156 
   157     return 1;   /* this audio target is available. */
   158 }
   159 
   160 AudioBootStrap DISKAUD_bootstrap = {
   161     "disk", "direct-to-disk audio", DISKAUD_Init, 1
   162 };
   163 
   164 #endif /* SDL_AUDIO_DRIVER_DISK */
   165 
   166 /* vi: set ts=4 sw=4 expandtab: */