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conf.c File Reference

Configuration helper functions. More...

Macros

#define ALSA_CONFIG_PATH_VAR   "ALSA_CONFIG_PATH"
#define ALSA_CONFIG_PATH_DEFAULT   ALSA_CONFIG_DIR "/alsa.conf"

Functions

int snd_config_substitute (snd_config_t *dst, snd_config_t *src)
 Substitutes one configuration node to another.
int snd_config_get_type_ascii (const char *ascii, snd_config_type_t *type)
 Converts an ASCII string to a configuration node type.
snd_config_type_t snd_config_get_type (const snd_config_t *config)
 Returns the type of a configuration node.
int snd_config_get_id (const snd_config_t *config, const char **id)
 Returns the id of a configuration node.
int snd_config_set_id (snd_config_t *config, const char *id)
 Sets the id of a configuration node.
int snd_config_top (snd_config_t **config)
 Creates a top level configuration node.
int snd_config_load (snd_config_t *config, snd_input_t *in)
 Loads a configuration tree.
int snd_config_load_override (snd_config_t *config, snd_input_t *in)
 Loads a configuration tree and overrides existing configuration nodes.
int snd_config_add (snd_config_t *parent, snd_config_t *child)
 Adds a child to a compound configuration node.
int snd_config_remove (snd_config_t *config)
 Removes a configuration node from its tree.
int snd_config_delete (snd_config_t *config)
 Frees a configuration node.
int snd_config_delete_compound_members (const snd_config_t *config)
 Deletes the children of a node.
int snd_config_make (snd_config_t **config, const char *id, snd_config_type_t type)
 Creates a configuration node.
int snd_config_make_integer (snd_config_t **config, const char *id)
 Creates an integer configuration node.
int snd_config_make_integer64 (snd_config_t **config, const char *id)
 Creates a 64-bit-integer configuration node.
int snd_config_make_real (snd_config_t **config, const char *id)
 Creates a real number configuration node.
int snd_config_make_string (snd_config_t **config, const char *id)
 Creates a string configuration node.
int snd_config_make_pointer (snd_config_t **config, const char *id)
 Creates a pointer configuration node.
int snd_config_make_compound (snd_config_t **config, const char *id, int join)
 Creates an empty compound configuration node.
int snd_config_imake_integer (snd_config_t **config, const char *id, const long value)
 Creates an integer configuration node with the given initial value.
int snd_config_imake_integer64 (snd_config_t **config, const char *id, const long long value)
 Creates a 64-bit-integer configuration node with the given initial value.
int snd_config_imake_real (snd_config_t **config, const char *id, const double value)
 Creates a real number configuration node with the given initial value.
int snd_config_imake_string (snd_config_t **config, const char *id, const char *value)
 Creates a string configuration node with the given initial value.
int snd_config_imake_pointer (snd_config_t **config, const char *id, const void *value)
 Creates a pointer configuration node with the given initial value.
int snd_config_set_integer (snd_config_t *config, long value)
 Changes the value of an integer configuration node.
int snd_config_set_integer64 (snd_config_t *config, long long value)
 Changes the value of a 64-bit-integer configuration node.
int snd_config_set_real (snd_config_t *config, double value)
 Changes the value of a real-number configuration node.
int snd_config_set_string (snd_config_t *config, const char *value)
 Changes the value of a string configuration node.
int snd_config_set_pointer (snd_config_t *config, const void *value)
 Changes the value of a pointer configuration node.
int snd_config_set_ascii (snd_config_t *config, const char *ascii)
 Changes the value of a configuration node.
int snd_config_get_integer (const snd_config_t *config, long *ptr)
 Returns the value of an integer configuration node.
int snd_config_get_integer64 (const snd_config_t *config, long long *ptr)
 Returns the value of a 64-bit-integer configuration node.
int snd_config_get_real (const snd_config_t *config, double *ptr)
 Returns the value of a real-number configuration node.
int snd_config_get_ireal (const snd_config_t *config, double *ptr)
 Returns the value of a real or integer configuration node.
int snd_config_get_string (const snd_config_t *config, const char **ptr)
 Returns the value of a string configuration node.
int snd_config_get_pointer (const snd_config_t *config, const void **ptr)
 Returns the value of a pointer configuration node.
int snd_config_get_ascii (const snd_config_t *config, char **ascii)
 Returns the value of a configuration node as a string.
int snd_config_test_id (const snd_config_t *config, const char *id)
 Compares the id of a configuration node to a given string.
int snd_config_save (snd_config_t *config, snd_output_t *out)
 Dumps the contents of a configuration node or tree.
int snd_config_search (snd_config_t *config, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree.
int snd_config_searcha (snd_config_t *root, snd_config_t *config, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree, expanding aliases.
int snd_config_searchv (snd_config_t *config, snd_config_t **result,...)
 Searches for a node in a configuration tree.
int snd_config_searchva (snd_config_t *root, snd_config_t *config, snd_config_t **result,...)
 Searches for a node in a configuration tree, expanding aliases.
int snd_config_search_alias (snd_config_t *config, const char *base, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree, expanding aliases.
int snd_config_search_hooks (snd_config_t *config, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree and expands hooks.
int snd_config_searcha_hooks (snd_config_t *root, snd_config_t *config, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree, expanding aliases and hooks.
int snd_config_searchva_hooks (snd_config_t *root, snd_config_t *config, snd_config_t **result,...)
 Searches for a node in a configuration tree, expanding aliases and hooks.
int snd_config_search_alias_hooks (snd_config_t *config, const char *base, const char *key, snd_config_t **result)
 Searches for a node in a configuration tree, using an alias and expanding hooks.
int snd_config_hook_load (snd_config_t *root, snd_config_t *config, snd_config_t **dst, snd_config_t *private_data)
 Loads and parses the given configurations files.
int snd_config_hook_load_for_all_cards (snd_config_t *root, snd_config_t *config, snd_config_t **dst, snd_config_t *private_data)
 Loads and parses the given configurations files for each installed sound card.
int snd_config_update_r (snd_config_t **_top, snd_config_update_t **_update, const char *cfgs)
 Updates a configuration tree by rereading the configuration files (if needed).
int snd_config_update (void)
 Updates snd_config by rereading the global configuration files (if needed).
int snd_config_update_free (snd_config_update_t *update)
 Frees a private update structure.
int snd_config_update_free_global (void)
 Frees the global configuration tree in snd_config.
snd_config_iterator_t snd_config_iterator_first (const snd_config_t *config)
 Returns an iterator pointing to a node's first child.
snd_config_iterator_t snd_config_iterator_next (const snd_config_iterator_t iterator)
 Returns an iterator pointing to the next sibling.
snd_config_iterator_t snd_config_iterator_end (const snd_config_t *config)
 Returns an iterator that ends a node's children list.
snd_config_tsnd_config_iterator_entry (const snd_config_iterator_t iterator)
 Returns the configuration node handle pointed to by an iterator.
int snd_config_copy (snd_config_t **dst, snd_config_t *src)
 Creates a copy of a configuration node.
int snd_config_evaluate (snd_config_t *config, snd_config_t *root, snd_config_t *private_data, snd_config_t **result)
 Evaluates a configuration node at runtime.
int snd_config_expand (snd_config_t *config, snd_config_t *root, const char *args, snd_config_t *private_data, snd_config_t **result)
 Expands a configuration node, applying arguments and functions.
int snd_config_search_definition (snd_config_t *config, const char *base, const char *name, snd_config_t **result)
 Searches for a definition in a configuration tree, using aliases and expanding hooks and arguments.

Variables

snd_config_tsnd_config = NULL
 Configuration top-level node (the global configuration).

Detailed Description

Configuration helper functions.

Author:
Abramo Bagnara abram.nosp@m.o@al.nosp@m.sa-pr.nosp@m.ojec.nosp@m.t.org
Jaroslav Kysela perex.nosp@m.@per.nosp@m.ex.cz
Date:
2000-2001

Tree based, full nesting configuration functions.

See the Configuration files page for more details.


Macro Definition Documentation

#define ALSA_CONFIG_PATH_DEFAULT   ALSA_CONFIG_DIR "/alsa.conf"

The name of the default files used by snd_config_update.

#define ALSA_CONFIG_PATH_VAR   "ALSA_CONFIG_PATH"

The name of the environment variable containing the files list for snd_config_update.


Function Documentation

int snd_config_get_type_ascii ( const char *  ascii,
snd_config_type_t type 
)

Converts an ASCII string to a configuration node type.

Parameters:
[in]asciiA string containing a configuration node type.
[out]typeThe node type corresponding to ascii.
Returns:
Zero if successful, otherwise a negative error code.

This function recognizes at least the following node types:

integer<dt>::SND_CONFIG_TYPE_INTEGER
integer64<dt>::SND_CONFIG_TYPE_INTEGER64
real<dt>::SND_CONFIG_TYPE_REAL
string<dt>::SND_CONFIG_TYPE_STRING
compound<dt>::SND_CONFIG_TYPE_COMPOUND
Errors:
-EINVAL
Unknown note type in type.
int snd_config_hook_load ( snd_config_t root,
snd_config_t config,
snd_config_t **  dst,
snd_config_t private_data 
)

Loads and parses the given configurations files.

Parameters:
[in]rootHandle to the root configuration node.
[in]configHandle to the configuration node for this hook.
[out]dstThe function puts the handle to the configuration node loaded from the file(s) at the address specified by dst.
[in]private_dataHandle to the private data configuration node.
Returns:
Zero if successful, otherwise a negative error code.

See Hooks in configuration files for an example.

int snd_config_hook_load_for_all_cards ( snd_config_t root,
snd_config_t config,
snd_config_t **  dst,
snd_config_t private_data 
)

Loads and parses the given configurations files for each installed sound card.

Parameters:
[in]rootHandle to the root configuration node.
[in]configHandle to the configuration node for this hook.
[out]dstThe function puts the handle to the configuration node loaded from the file(s) at the address specified by dst.
[in]private_dataHandle to the private data configuration node.
Returns:
Zero if successful, otherwise a negative error code.

This function works like snd_config_hook_load, but the files are loaded once for each sound card. The driver name is available with the private_string function to customize the file name.

int snd_config_remove ( snd_config_t config)

Removes a configuration node from its tree.

Parameters:
configHandle to the configuration node to be removed.
Returns:
Zero if successful, otherwise a negative error code.

This function makes config a top-level node, i.e., if config has a parent, then config is removed from the list of the parent's children.

This functions does not free the removed node.

See also:
snd_config_delete
int snd_config_search_alias ( snd_config_t config,
const char *  base,
const char *  key,
snd_config_t **  result 
)

Searches for a node in a configuration tree, expanding aliases.

Parameters:
[in]configHandle to the root of the configuration (sub)tree to search.
[in]baseSearch key base, or NULL.
[in]keySearch key suffix.
[out]resultWhen result != NULL, the function puts the handle to the node found at the address specified by result.
Returns:
Zero if successful, otherwise a negative error code.

This functions searches for a child node of config, allowing aliases, like snd_config_searcha. However, alias definitions are searched below config (there is no separate root parameter), and base specifies a seach key that identifies a compound node that is used to search for an alias definitions that is not found directly below config and that does not contain a period. In other words, when "id" is not found in config, this function also tries "base.id".

Errors:
-ENOENT
An id in key or an alias id does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound or string node.
int snd_config_search_alias_hooks ( snd_config_t config,
const char *  base,
const char *  key,
snd_config_t **  result 
)

Searches for a node in a configuration tree, using an alias and expanding hooks.

Parameters:
[in]configHandle to the root of the configuration (sub)tree to search.
[in]baseSearch key base, or NULL.
[in]keySearch key suffix.
[out]resultThe function puts the handle to the node found at the address specified by result.
Returns:
Zero if successful, otherwise a negative error code.

This functions searches for a child node of config, allowing aliases, like snd_config_search_alias, and expanding hooks, like snd_config_search_hooks.

Errors:
-ENOENT
An id in key or an alias id does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound node.
Additionally, any errors encountered when parsing the hook definitions or returned by the hook functions.
int snd_config_search_hooks ( snd_config_t config,
const char *  key,
snd_config_t **  result 
)

Searches for a node in a configuration tree and expands hooks.

Parameters:
[in,out]configHandle to the root of the configuration (sub)tree to search.
[in]keySearch key: one or more node keys, separated with dots.
[out]resultThe function puts the handle to the node found at the address specified by result.
Returns:
Zero if successful, otherwise a negative error code.

This functions searches for a child node of config like snd_config_search, but any compound nodes to be searched that contain hooks are modified by the respective hook functions.

Errors:
-ENOENT
An id in key does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound node.
Additionally, any errors encountered when parsing the hook definitions or returned by the hook functions.
int snd_config_searcha ( snd_config_t root,
snd_config_t config,
const char *  key,
snd_config_t **  result 
)

Searches for a node in a configuration tree, expanding aliases.

Parameters:
[in]rootHandle to the root configuration node containing alias definitions.
[in]configHandle to the root of the configuration (sub)tree to search.
[in]keySearch key: one or more node keys, separated with dots.
[out]resultWhen result != NULL, the function puts the handle to the node found at the address specified by result.
Returns:
Zero if successful, otherwise a negative error code.

This functions searches for a child node of config like snd_config_search. However, any compound node can also be identified by an alias, which is a string node whose value is taken as the id of a compound node below root.

root must be a compound node. root and config may be the same node.

For example, with the following configuration, the call

snd_config_searcha(root, config, "a.b.c.d", &result);

would return the node with id d:

config {
a {
b bb
}
}
root {
bb {
c cc
}
cc ccc
ccc {
d {
x "icks"
}
}
}
Errors:
-ENOENT
An id in key or an alias id does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound or string node.
int snd_config_searcha_hooks ( snd_config_t root,
snd_config_t config,
const char *  key,
snd_config_t **  result 
)

Searches for a node in a configuration tree, expanding aliases and hooks.

Parameters:
[in]rootHandle to the root configuration node containing alias definitions.
[in,out]configHandle to the root of the configuration (sub)tree to search.
[in]keySearch key: one or more node keys, separated with dots.
[out]resultThe function puts the handle to the node found at the address specified by result.
Returns:
Zero if successful, otherwise a negative error code.

This function searches for a child node of config, allowing aliases, like snd_config_searcha, and expanding hooks, like snd_config_search_hooks.

Errors:
-ENOENT
An id in key or an alias id does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound node.
Additionally, any errors encountered when parsing the hook definitions or returned by the hook functions.
int snd_config_searchva ( snd_config_t root,
snd_config_t config,
snd_config_t **  result,
  ... 
)

Searches for a node in a configuration tree, expanding aliases.

Parameters:
[in]rootHandle to the root configuration node containing alias definitions.
[in]configHandle to the root of the configuration (sub)tree to search.
[out]resultWhen result != NULL, the function puts the handle to the node found at the address specified by result.
[in]...One or more concatenated dot separated search keys, terminated with NULL.
Returns:
Zero if successful, otherwise a negative error code.

This function searches for a child node of config, allowing aliases, like snd_config_searcha, but the search key is the concatenation of all passed seach key strings, like with snd_config_searchv.

Errors:
-ENOENT
An id in a search key does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound or string node.
int snd_config_searchva_hooks ( snd_config_t root,
snd_config_t config,
snd_config_t **  result,
  ... 
)

Searches for a node in a configuration tree, expanding aliases and hooks.

Parameters:
[in]rootHandle to the root configuration node containing alias definitions.
[in,out]configHandle to the root of the configuration (sub)tree to search.
[out]resultThe function puts the handle to the node found at the address specified by result.
[in]...One or more concatenated dot separated search keys, terminated with NULL.
Returns:
Zero if successful, otherwise a negative error code.

This function searches for a child node of config, allowing aliases and expanding hooks like snd_config_searcha_hooks, but the search key is the concatenation of all passed seach key strings, like with snd_config_searchv.

Errors:
-ENOENT
An id in key or an alias id does not exist.
-ENOENT
config or one of its child nodes to be searched is not a compound node.
Additionally, any errors encountered when parsing the hook definitions or returned by the hook functions.
int snd_config_substitute ( snd_config_t dst,
snd_config_t src 
)

Substitutes one configuration node to another.

Parameters:
dstHandle to the destination node.
srcHandle to the source node. Must not be the same as dst.
Returns:
Zero if successful, otherwise a negative error code.

If both nodes are compounds, the source compound node members are appended to the destination compound node.

If the destination node is a compound and the source node is an ordinary type, the compound members are deleted (including their contents).

Otherwise, the source node's value replaces the destination node's value.

In any case, a successful call to this function frees the source node.