src/filter/null_filter_plugin.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 /** \file
  21  *
  22  * This filter plugin does nothing.  That is not quite useful, except
  23  * for testing the filter core, or as a template for new filter
  24  * plugins.
  25  */
  26
  27 #include "config.h"
  28 #include "filter_plugin.h"
  29 #include "filter_internal.h"
  30 #include "filter_registry.h"
  31
  32 #include <assert.h>
  33
  34 struct null_filter {
  35         struct filter filter;
  36 };
  37
  38 static struct filter *
  39 null_filter_init(G_GNUC_UNUSED const struct config_param *param,
  40                  G_GNUC_UNUSED GError **error_r)
  41 {
  42         struct null_filter *filter = g_new(struct null_filter, 1);
  43
  44         filter_init(&filter->filter, &null_filter_plugin);
  45         return &filter->filter;
  46 }
  47
  48 static void
  49 null_filter_finish(struct filter *_filter)
  50 {
  51         struct null_filter *filter = (struct null_filter *)_filter;
  52
  53         g_free(filter);
  54 }
  55
  56 static const struct audio_format *
  57 null_filter_open(struct filter *_filter, struct audio_format *audio_format,
  58                  G_GNUC_UNUSED GError **error_r)
  59 {
  60         struct null_filter *filter = (struct null_filter *)_filter;
  61         (void)filter;
  62
  63         return audio_format;
  64 }
  65
  66 static void
  67 null_filter_close(struct filter *_filter)
  68 {
  69         struct null_filter *filter = (struct null_filter *)_filter;
  70         (void)filter;
  71 }
  72
  73 static const void *
  74 null_filter_filter(struct filter *_filter,
  75                    const void *src, size_t src_size,
  76                    size_t *dest_size_r, G_GNUC_UNUSED GError **error_r)
  77 {
  78         struct null_filter *filter = (struct null_filter *)_filter;
  79         (void)filter;
  80
  81         /* return the unmodified source buffer */
  82         *dest_size_r = src_size;
  83         return src;
  84 }
  85
  86 const struct filter_plugin null_filter_plugin = {
  87         .name = "null",
  88         .init = null_filter_init,
  89         .finish = null_filter_finish,
  90         .open = null_filter_open,
  91         .close = null_filter_close,
  92         .filter = null_filter_filter,
  93 };