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101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/**
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* \file control/control_empty.c
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* \ingroup Control_Plugins
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* \brief Control Empty Plugin Interface
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* \author Jaroslav Kysela <perex@perex.cz>
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* \date 2021
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*/
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/*
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* Control - Empty plugin
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* Copyright (c) 2021 by Jaroslav Kysela <perex@perex.cz>
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*
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include "control_local.h"
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#ifndef PIC
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/* entry for static linking */
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const char *_snd_module_control_empty = "";
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#endif
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/*! \page control_plugins
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\section control_plugins_empty Plugin: Empty
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This plugin just redirects the control device to another plugin.
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\code
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ctl.name {
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type empty # Empty Control
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child STR # Slave name
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# or
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child { # Child definition
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...
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}
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}
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\endcode
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\subsection control_plugins_empty_funcref Function reference
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<UL>
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<LI>_snd_ctl_empty_open()
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</UL>
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*/
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/**
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* \brief Creates a new Empty Control
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* \param handlep Returns created Control handle
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* \param name Name of Control
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* \param root Root configuration node
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* \param conf Configuration node with empty Control description
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* \param mode Control mode
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* \retval zero on success otherwise a negative error code
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* \warning Using of this function might be dangerous in the sense
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* of compatibility reasons. The prototype might be freely
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* changed in future.
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*/
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int _snd_ctl_empty_open(snd_ctl_t **handlep, const char *name ATTRIBUTE_UNUSED,
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snd_config_t *root, snd_config_t *conf, int mode)
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{
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snd_config_t *child = NULL;
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snd_config_iterator_t i, next;
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snd_config_for_each(i, next, conf) {
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snd_config_t *n = snd_config_iterator_entry(i);
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const char *id;
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if (snd_config_get_id(n, &id) < 0)
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continue;
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if (_snd_conf_generic_id(id))
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continue;
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if (strcmp(id, "child") == 0) {
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child = n;
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continue;
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}
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snd_error(CONTROL, "Unknown field %s", id);
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return -EINVAL;
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}
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if (!child) {
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snd_error(CONTROL, "child is not defined");
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return -EINVAL;
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}
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return _snd_ctl_open_named_child(handlep, name, root, child, mode, conf);
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}
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#ifndef DOC_HIDDEN
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SND_DLSYM_BUILD_VERSION(_snd_ctl_empty_open, SND_CONTROL_DLSYM_VERSION);
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#endif
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