audio_stdout.c

   1 /*
   2  * stdout output driver. This file is part of Shairport Sync.
   3  * Copyright (c) Mike Brady 2015
   4  *
   5  * Based on pipe output driver
   6  * Copyright (c) James Laird 2013
   7  * All rights reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person
  10  * obtaining a copy of this software and associated documentation
  11  * files (the "Software"), to deal in the Software without
  12  * restriction, including without limitation the rights to use,
  13  * copy, modify, merge, publish, distribute, sublicense, and/or
  14  * sell copies of the Software, and to permit persons to whom the
  15  * Software is furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be
  18  * included in all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  22  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  24  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  25  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  26  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  27  * OTHER DEALINGS IN THE SOFTWARE.
  28  */
  29
  30 #include "audio.h"
  31 #include "common.h"
  32 #include <errno.h>
  33 #include <fcntl.h>
  34 #include <memory.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <unistd.h>
  38
  39 static int fd = -1;
  40 static int warned = 0;
  41
  42 static void start(__attribute__((unused)) int sample_rate,
  43                   __attribute__((unused)) int sample_format) {
  44   fd = STDOUT_FILENO;
  45   warned = 0;
  46 }
  47
  48 static int play(void *buf, int samples, __attribute__((unused)) int sample_type,
  49                 __attribute__((unused)) uint32_t timestamp,
  50                 __attribute__((unused)) uint64_t playtime) {
  51   char errorstring[1024];
  52   int rc = write(fd, buf, samples * 4);
  53   if ((rc < 0) && (warned == 0)) {
  54     strerror_r(errno, (char *)errorstring, 1024);
  55     warn("Error %d writing to stdout (fd: %d): \"%s\".", errno, fd, errorstring);
  56     warned = 1;
  57   }
  58   return rc;
  59 }
  60
  61 static void stop(void) {
  62   // Do nothing when play stops
  63 }
  64
  65 static int init(__attribute__((unused)) int argc, __attribute__((unused)) char **argv) {
  66   // set up default values first
  67   config.audio_backend_buffer_desired_length = 1.0;
  68   config.audio_backend_latency_offset = 0;
  69
  70   // get settings from settings file
  71   // do the "general" audio  options. Note, these options are in the "general" stanza!
  72   parse_general_audio_options();
  73   return 0;
  74 }
  75
  76 static void deinit(void) {
  77   // don't close stdout
  78 }
  79
  80 audio_output audio_stdout = {.name = "stdout",
  81                              .help = NULL,
  82                              .init = &init,
  83                              .deinit = &deinit,
  84                              .prepare = NULL,
  85                              .start = &start,
  86                              .stop = &stop,
  87                              .is_running = NULL,
  88                              .flush = NULL,
  89                              .delay = NULL,
  90                              .stats = NULL,
  91                              .play = &play,
  92                              .volume = NULL,
  93                              .parameters = NULL,
  94                              .mute = NULL};