src/audio/disk/SDL_diskaudio.c
author Sam Lantinga <slouken@libsdl.org>
Sat, 02 Jan 2016 10:10:34 -0800
changeset 9998 f67cf37e9cd4
parent 9786 d857f324bede
child 10255 9530fc07da6c
permissions -rw-r--r--
Updated copyright to 2016
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2016 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     /* handle != NULL means "user specified the placeholder name on the fake detected device list" */
   106     const char *fname = DISKAUD_GetOutputFilename(handle ? NULL : devname);
   107     const char *envr = SDL_getenv(DISKENVR_WRITEDELAY);
   108 
   109     this->hidden = (struct SDL_PrivateAudioData *)
   110         SDL_malloc(sizeof(*this->hidden));
   111     if (this->hidden == NULL) {
   112         return SDL_OutOfMemory();
   113     }
   114     SDL_memset(this->hidden, 0, sizeof(*this->hidden));
   115 
   116     this->hidden->mixlen = this->spec.size;
   117     this->hidden->write_delay =
   118         (envr) ? SDL_atoi(envr) : DISKDEFAULT_WRITEDELAY;
   119 
   120     /* Open the audio device */
   121     this->hidden->output = SDL_RWFromFile(fname, "wb");
   122     if (this->hidden->output == NULL) {
   123         DISKAUD_CloseDevice(this);
   124         return -1;
   125     }
   126 
   127     /* Allocate mixing buffer */
   128     this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
   129     if (this->hidden->mixbuf == NULL) {
   130         DISKAUD_CloseDevice(this);
   131         return -1;
   132     }
   133     SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
   134 
   135 #if HAVE_STDIO_H
   136     fprintf(stderr,
   137             "WARNING: You are using the SDL disk writer audio driver!\n"
   138             " Writing to file [%s].\n", fname);
   139 #endif
   140 
   141     /* We're ready to rock and roll. :-) */
   142     return 0;
   143 }
   144 
   145 static void
   146 DISKAUD_DetectDevices(void)
   147 {
   148     /* !!! FIXME: stole this literal string from DEFAULT_OUTPUT_DEVNAME in SDL_audio.c */
   149     SDL_AddAudioDevice(SDL_FALSE, "System audio output device", (void *) 0x1);
   150 }
   151 
   152 static int
   153 DISKAUD_Init(SDL_AudioDriverImpl * impl)
   154 {
   155     /* Set the function pointers */
   156     impl->OpenDevice = DISKAUD_OpenDevice;
   157     impl->WaitDevice = DISKAUD_WaitDevice;
   158     impl->PlayDevice = DISKAUD_PlayDevice;
   159     impl->GetDeviceBuf = DISKAUD_GetDeviceBuf;
   160     impl->CloseDevice = DISKAUD_CloseDevice;
   161     impl->DetectDevices = DISKAUD_DetectDevices;
   162 
   163     impl->AllowsArbitraryDeviceNames = 1;
   164 
   165     return 1;   /* this audio target is available. */
   166 }
   167 
   168 AudioBootStrap DISKAUD_bootstrap = {
   169     "disk", "direct-to-disk audio", DISKAUD_Init, 1
   170 };
   171 
   172 #endif /* SDL_AUDIO_DRIVER_DISK */
   173 
   174 /* vi: set ts=4 sw=4 expandtab: */