alsa-utils/topology/topology.h
Ranjani Sridharan 90f5967178 topology: pre-processor: Move the call to expand variables
Remove the call to snd_config_expand_custom() to expand the top-level
input config. And replace it with calls to snd_config_evaluate_string()
for each non-compound config while processing individual objects. This
will allow retreving variable definitions from object attribute values
and global definitions.

Add a new field "current_obj_cfg" to hold the current object config
being pre-processed.

This will facilitate adding simple math expressions for computing
attribute values for objects based on other attributes. For ex: we can
set the expression for buffer size as follows:

buffer_size "$[($in_channels * 48) * 4]"

The buffer_size attribute value will be computed with the attribute
value "in_channels" based on the expression above. So if $in_channels =
2, buffer_size will be evaluated to 384.

Additionally this change also permits computing attribute values based
on previously computed values. For example:

buffer_size "$[($in_channels * 48) * 4]"
dma_buffer_size "$[$buffer_size * 2]"

dma_buffer_size will be computed as 768. Note that the order of
definitions for buffer_size and dma_buffer_size matters because the
evaluation for dma_buffer_size depends on the evaluation of buffer_size.
In order to conform to this, the tplg_object_copy_and_add_param() is
modified to add attribute configs from class config to an object using
snd_config_before() instead of snd_config_add().

With this change, we no longer need to set the auto_attr_updater for
buffer type widget objects. So remove it.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
2021-12-19 20:32:38 +01:00

36 lines
1.3 KiB
C

/*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef __TOPOLOGY_H
#define __TOPOLOGY_H
#include <stdlib.h>
/* pre_processor */
struct tplg_pre_processor {
snd_config_t *input_cfg;
snd_config_t *output_cfg;
snd_output_t *output;
snd_output_t *dbg_output;
snd_config_t *current_obj_cfg;
};
int pre_process(struct tplg_pre_processor *tplg_pp, char *config, size_t config_size,
const char *pre_processor_defs, const char *inc_path);
int init_pre_processor(struct tplg_pre_processor **tplg_pp, snd_output_type_t type,
const char *output_file);
void free_pre_preprocessor(struct tplg_pre_processor *tplg_pp);
#endif