src/audio/disk/SDL_diskaudio.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 26 May 2015 06:27:46 -0700
changeset 9619 b94b6d0bff0f
parent 9394 bb28e5281770
child 9786 d857f324bede
permissions -rw-r--r--
Updated the copyright year to 2015
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2015 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_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         SDL_OpenedAudioDeviceDisconnected(this);
    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         SDL_FreeAudioMem(this->hidden->mixbuf);
    92         this->hidden->mixbuf = NULL;
    93         if (this->hidden->output != NULL) {
    94             SDL_RWclose(this->hidden->output);
    95             this->hidden->output = NULL;
    96         }
    97         SDL_free(this->hidden);
    98         this->hidden = NULL;
    99     }
   100 }
   101 
   102 static int
   103 DISKAUD_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
   104 {
   105     const char *envr = SDL_getenv(DISKENVR_WRITEDELAY);
   106     const char *fname = DISKAUD_GetOutputFilename(devname);
   107 
   108     this->hidden = (struct SDL_PrivateAudioData *)
   109         SDL_malloc(sizeof(*this->hidden));
   110     if (this->hidden == NULL) {
   111         return SDL_OutOfMemory();
   112     }
   113     SDL_memset(this->hidden, 0, sizeof(*this->hidden));
   114 
   115     this->hidden->mixlen = this->spec.size;
   116     this->hidden->write_delay =
   117         (envr) ? SDL_atoi(envr) : DISKDEFAULT_WRITEDELAY;
   118 
   119     /* Open the audio device */
   120     this->hidden->output = SDL_RWFromFile(fname, "wb");
   121     if (this->hidden->output == NULL) {
   122         DISKAUD_CloseDevice(this);
   123         return -1;
   124     }
   125 
   126     /* Allocate mixing buffer */
   127     this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
   128     if (this->hidden->mixbuf == NULL) {
   129         DISKAUD_CloseDevice(this);
   130         return -1;
   131     }
   132     SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
   133 
   134 #if HAVE_STDIO_H
   135     fprintf(stderr,
   136             "WARNING: You are using the SDL disk writer audio driver!\n"
   137             " Writing to file [%s].\n", fname);
   138 #endif
   139 
   140     /* We're ready to rock and roll. :-) */
   141     return 0;
   142 }
   143 
   144 static int
   145 DISKAUD_Init(SDL_AudioDriverImpl * impl)
   146 {
   147     /* Set the function pointers */
   148     impl->OpenDevice = DISKAUD_OpenDevice;
   149     impl->WaitDevice = DISKAUD_WaitDevice;
   150     impl->PlayDevice = DISKAUD_PlayDevice;
   151     impl->GetDeviceBuf = DISKAUD_GetDeviceBuf;
   152     impl->CloseDevice = DISKAUD_CloseDevice;
   153 
   154     impl->AllowsArbitraryDeviceNames = 1;
   155 
   156     return 1;   /* this audio target is available. */
   157 }
   158 
   159 AudioBootStrap DISKAUD_bootstrap = {
   160     "disk", "direct-to-disk audio", DISKAUD_Init, 1
   161 };
   162 
   163 #endif /* SDL_AUDIO_DRIVER_DISK */
   164 
   165 /* vi: set ts=4 sw=4 expandtab: */