alsa-lib/src/conf.c

/**
 * \file conf.c
 * \ingroup Configuration
 * \brief Configuration helper functions
 * \author Abramo Bagnara <abramo@alsa-project.org>
 * \author Jaroslav Kysela <perex@suse.cz>
 * \date 2000-2001
 *
 * Tree based, full nesting configuration functions.
 *
 * See the \ref conf page for more details.
 */
/*
 *  Configuration helper functions
 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>,
 *			  Jaroslav Kysela <perex@suse.cz>
 *
 *
 *   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 2.1 of
 *   the License, or (at your option) any later version.
 *
 *   This program 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 Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

/*! \page conf Configuration files

<P>Configuration files are using a simple format allowing the modern
data description like nesting and array assignments.</P>

\section conf_whitespace Whitespace

Whitespace is the collective name given to spaces (blanks), horizontal and
vertical tabs, newline characters, and comments. Whitespace can serve to
indicate where configuration tokens start and end, but beyond this function,
any surplus whitespace is discarded. For example, the two sequences

\code
  a 1 b 2
\endcode

and

\code
  a 1 
     b 2
\endcode

are lexically equivalent and parse identically to give the four tokens:

\code
a
1
b
2
\endcode

The ASCII characters representing whitespace can occur within literal
strings, int which case they are protected from the normal parsing process
(they remain as part of the string). For example:

\code
  name "John Smith"
\endcode

parses to two tokens, including the single literal-string token "John
Smith".

\section conf_linesplicing Line splicing with \

A special case occurs, if the final newline character encountered is
preceded by a backslash (\) in the string value definition. The backslash
and new line are both discarded, allowing two physical lines of text to be
treated as one unit.

\code
"John \
Smith"
\endcode

is parsed as "John Smith".

\section conf_comments Comments

A single-line comments are defined using character #. The comment can start
in any position, and extends until the next new line.

\code
  a 1  # this is a comment
\endcode

\section conf_include Include another configuration file

A new configuration file can be included using <filename> syntax. The global
configuration directory can be referenced using <confdir:filename> syntax.

\code
</etc/alsa1.conf>
<confdir:pcm/surround.conf>
\endcode

\section conf_punctuators Punctuators

The configuration punctuators (also known as separators) are:

\code
  {} [] , ; = . ' " new-line form-feed carriage-return whitespace
\endcode

\subsection conf_braces Braces

Open and close braces { } indicate the start and end of a compound
statement:

\code
a {
  b 1
}
\endcode

\subsection conf_brackets Brackets

Open and close brackets indicate single array definition. The identifiers
are automatically generated starting with zero.

\code
a [
  "first"
  "second"
]
\endcode

Above code is equal to

\code
a.0 "first"
a.1 "second"
\endcode

\subsection conf_comma_semicolon Comma and semicolon

The comma (,) or semicolon (;) can separate the value assignments. It is not
strictly required to use these separators, because any whitespace supplies
them.

\code
a 1;
b 1,
\endcode

\subsection conf_equal Equal sign

The equal sign (=) separates can separate variable declarations from
initialization lists:

\code
a=1
b=2
\endcode

Using the equal signs is not required, because any whitespace supplies
them.

\section conf_assigns Assigns

The configuration file defines id (key) and value pairs. The id (key) can be
composed from any ASCII digits or chars from a to z or A to Z, including
char _. The value can be either a string, integer or real number.

\subsection conf_single Single assign

\code
a 1	# is equal to
a=1	# is equal to
a=1;	# is equal to
a 1,
\endcode

\subsection conf_compound Compound assign (definition using braces)

\code
a {
  b = 1
}
a={
  b 1,
}
\endcode

\section conf_compound1 Compound assign (one key definition)

\code
a.b 1
a.b=1
\endcode

\subsection conf_array Array assign (definition using brackets)

\code
a [
  "first"
  "second"
]
\endcode

\subsection conf_array1 Array assign (one key definition)

\code
a.0 "first"
a.1 "second"
\endcode

\section conf_mode Parsed node operation mode

By default, the node operation node is 'merge+create'. It means, if
a configuration node is not present a new one is created, otherwise
the latest assignment is merged (if possible - type checking). The
'merge+create' operation mode is specified with a prefix char plus (+).

The operation mode 'merge' merges the node with old one (which must
exists). Type checking is done, so string cannot be assigned to integer
and so on. This mode is specified with a prefix char minus (-).

The operation mode 'do not override' ignores a new configuration node
if a configuration node with same name exists. This mode is specified with
a prefix char note of interrogation (?).

The operation mode 'override' always overrides the old configuration node
with new contents. This mode is specified with a prefix char note of
exclamation (!).

\code
defaults.pcm.!device 1
\endcode

\section conf_syntax_summary Syntax summary

\code
# Configuration file syntax

# Include a new configuration file
<filename>

# Simple assign
name [=] value [,|;]

# Compound assign (first style)
name [=] {
        name1 [=] value [,|;]
        ...
}

# Compound assign (second style)
name.name1 [=] value [,|;]

# Array assign (first style)
name [
        value0 [,|;]
        value1 [,|;]
        ...
]

# Array assign (second style)
name.0 [=] value0 [,|;]
name.1 [=] value1 [,|;]
\endcode

\section conf_syntax_ref References

\ref confarg
\ref conffunc
\ref confhooks

*/

/*! \page confarg Configuration - runtime arguments

<P>The ALSA library can accept runtime arguments for some configuration
blocks. This extension is on top of the basic syntax of the configuration
files.<P>

\section confarg_define Defining arguments

Arguments are specified by id (key) @args and array values containing
the string names of arguments:

\code
@args [ CARD ]	# or
@args.0 CARD
\endcode

\section confarg_type Defining argument type and default value

Arguments type is specified by id (key) @args and argument name. The type
and default value is specified in the compound:

\code
@args.CARD {
  type string
  default "abcd"
}
\endcode

\section confarg_refer Referring argument

Arguments are referred by dollar-sign ($) and name of argument:

\code
  card $CARD
\endcode

\section confarg_usage Usage

Arguments are replaced with real values when the key contains part after
colon (:). For example, all these names for PCM interface gives same result:

\code
hw:0,1
hw:CARD=0,DEV=1
hw:{CARD 0 DEV 1}
plug:"hw:0,1"
plug:{SLAVE="hw:{CARD 0 DEV 1}"}
\endcode

As you see, the argument can be specified by order or by name. Note that
arguments closed into braces are parsed in same way like configuration files,
but with the override method by default.

\section confarg_example Example

\code
pcm.demo {
	@args [ CARD DEVICE ]
	@args.CARD {
		type string
		default "supersonic"
	}
	@args.DEVICE {
		type integer
		default 0
	}
	type hw
	card $CARD
	device $DEVICE
}
\endcode

*/

/*! \page conffunc Configuration - runtime functions

<P>The ALSA library accepts the runtime modification of configuration.
The several build-in functions are available.</P>

<P>The function is referred using id @func and function name. All other
values in the current compound are used as configuration for the function.
If compound func.<function_name> is defined in the root leafs, then library
and function from this compound configuration is used, otherwise the prefix
'snd_func_' is added to string and the code from the ALSA library is used.
The definition of function looks like:</P> 

\code
func.remove_first_char {
	lib "/usr/lib/libasoundextend.so"
	func "extend_remove_first_char"
}
\endcode

*/

/*! \page confhooks Configuration - hooks

<P>The hook extension in the ALSA library allows expanding of configuration
nodes at run-time lookup. The presence of a hook is determined with a @hooks
compound node.</P>

<P>The example definition a hook which loads two configuration files at beginning:</P>

\code
@hooks [
	{
		func load
		files [
			"/etc/asound.conf"
			"~/.asoundrc"
		]
		errors false
	}
]
\endcode

\section confhooks_ref Function reference

<UL>
  <LI>The function load - snd_config_hook_load() - loads and parses the given
      configuration files.
  <LI>The function load_for_all_cards - snd_config_hook_load_for_all_cards() -
      loads and parses the given configuration files for all installed sound-cards.
      The driver name (type of sound-card) is passed in the private configuration
      node.
</UL>

*/


#include <stdarg.h>
#include <wordexp.h>
#include <dlfcn.h>
#include <limits.h>
#include <sys/stat.h>
#include <pthread.h>
#include "local.h"

#ifndef DOC_HIDDEN

struct _snd_config {
	char *id;
	snd_config_type_t type;
	union {
		long integer;
		long long integer64;
		char *string;
		double real;
		const void *ptr;
		struct {
			struct list_head fields;
			int join;
		} compound;
	} u;
	struct list_head list;
	snd_config_t *father;
};

struct filedesc {
	char *name;
	snd_input_t *in;
	unsigned int line, column;
	struct filedesc *next;
};

#define LOCAL_ERROR			(-0x68000000)

#define LOCAL_UNTERMINATED_STRING 	(LOCAL_ERROR - 0)
#define LOCAL_UNTERMINATED_QUOTE	(LOCAL_ERROR - 1)
#define LOCAL_UNEXPECTED_CHAR		(LOCAL_ERROR - 2)
#define LOCAL_UNEXPECTED_EOF		(LOCAL_ERROR - 3)

typedef struct {
	struct filedesc *current;
	int unget;
	int ch;
} input_t;

int safe_strtoll(const char *str, long long *val)
{
	long long v;
	if (!*str)
		return -EINVAL;
	errno = 0;
	if (sscanf(str, "%Ld", &v) != 1)
		return -EINVAL;
	*val = v;
	return 0;
}

int safe_strtol(const char *str, long *val)
{
	char *end;
	long v;
	if (!*str)
		return -EINVAL;
	errno = 0;
	v = strtol(str, &end, 0);
	if (errno)
		return -errno;
	if (*end)
		return -EINVAL;
	*val = v;
	return 0;
}

static int safe_strtod(const char *str, double *val)
{
	char *end;
	double v;
	if (!*str)
		return -EINVAL;
	errno = 0;
	v = strtod(str, &end);
	if (errno)
		return -errno;
	if (*end)
		return -EINVAL;
	*val = v;
	return 0;
}

static int get_char(input_t *input)
{
	int c;
	struct filedesc *fd;
	if (input->unget) {
		input->unget = 0;
		return input->ch;
	}
 again:
	fd = input->current;
	c = snd_input_getc(fd->in);
	switch (c) {
	case '\n':
		fd->column = 0;
		fd->line++;
		break;
	case '\t':
		fd->column += 8 - fd->column % 8;
		break;
	case EOF:
		if (fd->next) {
			snd_input_close(fd->in);
			free(fd->name);
			input->current = fd->next;
			free(fd);
			goto again;
		}
		return LOCAL_UNEXPECTED_EOF;
	default:
		fd->column++;
		break;
	}
	return (unsigned char)c;
}

static void unget_char(int c, input_t *input)
{
	assert(!input->unget);
	input->ch = c;
	input->unget = 1;
}

static int get_delimstring(char **string, int delim, input_t *input);

static int get_char_skip_comments(input_t *input)
{
	int c;
	while (1) {
		c = get_char(input);
		if (c == '<') {
			char *str;
			snd_input_t *in;
			struct filedesc *fd;
			int err = get_delimstring(&str, '>', input);
			if (err < 0)
				return err;
			if (!strncmp(str, "confdir:", 8)) {
				char *tmp = malloc(strlen(DATADIR "/alsa") + 1 + strlen(str + 8) + 1);
				if (tmp == NULL) {
					free(str);
					return -ENOMEM;
				}
				sprintf(tmp, DATADIR "/alsa/%s", str + 8);
				free(str);
				str = tmp;
			}
			err = snd_input_stdio_open(&in, str, "r");
			if (err < 0) {
				free(str);
				return err;
			}
			fd = malloc(sizeof(*fd));
			if (!fd) {
				free(str);
				return -ENOMEM;
			}
			fd->name = str;
			fd->in = in;
			fd->next = input->current;
			fd->line = 1;
			fd->column = 0;
			input->current = fd;
			continue;
		}
		if (c != '#')
			break;
		while (1) {
			c = get_char(input);
			if (c < 0)
				return c;
			if (c == '\n')
				break;
		}
	}
		
	return c;
}
			

static int get_nonwhite(input_t *input)
{
	int c;
	while (1) {
		c = get_char_skip_comments(input);
		switch (c) {
		case ' ':
		case '\f':
		case '\t':
		case '\n':
		case '\r':
			break;
		default:
			return c;
		}
	}
}

static int get_quotedchar(input_t *input)
{
	int c;
	c = get_char(input);
	switch (c) {
	case 'n':
		return '\n';
	case 't':
		return '\t';
	case 'v':
		return '\v';
	case 'b':
		return '\b';
	case 'r':
		return '\r';
	case 'f':
		return '\f';
	case '0' ... '7':
	{
		int num = c - '0';
		int i = 1;
		do {
			c = get_char(input);
			if (c < '0' || c > '7') {
				unget_char(c, input);
				break;
			}
			num = num * 8 + c - '0';
			i++;
		} while (i < 3);
		return num;
	}
	default:
		return c;
	}
}

static int get_freestring(char **string, int id, input_t *input)
{
	const size_t bufsize = 64;
	char _buf[bufsize];
	char *buf = _buf;
	size_t alloc = bufsize;
	size_t idx = 0;
	int c;
	while (1) {
		c = get_char(input);
		if (c < 0) {
			if (c == LOCAL_UNEXPECTED_EOF) {
				char *s = malloc(idx + 1);
				if (!s)
					return -ENOMEM;
				memcpy(s, buf, idx);
				s[idx] = '\0';
				*string = s;
				c = 0;
			}
			if (alloc > bufsize)
				free(buf);
			return c;
		}
		switch (c) {
		case '.':
			if (!id)
				break;
		case ' ':
		case '\f':
		case '\t':
		case '\n':
		case '\r':
		case '=':
		case ',':
		case ';':
		case '{':
		case '}':
		case '[':
		case ']':
		case '\'':
		case '"':
		case '\\':
		case '#':
		{
			char *s = malloc(idx + 1);
			if (!s)
				return -ENOMEM;
			unget_char(c, input);
			memcpy(s, buf, idx);
			s[idx] = '\0';
			*string = s;
			if (alloc > bufsize)
				free(buf);
			return 0;
		}
		default:
			break;
		}
		if (idx >= alloc) {
			size_t old_alloc = alloc;
			alloc *= 2;
			if (old_alloc == bufsize) {
				buf = malloc(alloc);
				if (buf == NULL)
					return -ENOMEM;
				memcpy(buf, _buf, old_alloc);
			} else {
				char *ptr = realloc(buf, alloc);
				if (ptr == NULL) {
					free(buf);
					return -ENOMEM;
				}
				buf = ptr;
			}
		}
		buf[idx++] = c;
	}
	return 0;
}
			
static int get_delimstring(char **string, int delim, input_t *input)
{
	const size_t bufsize = 64;
	char _buf[bufsize];
	char *buf = _buf;
	size_t alloc = bufsize;
	size_t idx = 0;
	int c;
	while (1) {
		c = get_char(input);
		if (c < 0)
			return c;
		switch (c) {
		case '\\':
			c = get_quotedchar(input);
			if (c < 0)
				return c;
			if (c == '\n')
				continue;
			break;
		default:
			if (c == delim) {
				char *s = malloc(idx + 1);
				if (!s)
					return -ENOMEM;
				memcpy(s, buf, idx);
				s[idx] = '\0';
				*string = s;
				if (alloc > bufsize)
					free(buf);
				return 0;
			}
		}
		if (idx >= alloc) {
			size_t old_alloc = alloc;
			alloc *= 2;
			if (old_alloc == bufsize) {
				buf = malloc(alloc);
				if (buf == NULL)
					return -ENOMEM;
				memcpy(buf, _buf, old_alloc);
			} else {
				char *ptr = realloc(buf, alloc);
				if (ptr == NULL) {
					free(buf);
					return -ENOMEM;
				}
				buf = ptr;
			}
		}
		buf[idx++] = c;
	}
}

/* Return 0 for free string, 1 for delimited string */
static int get_string(char **string, int id, input_t *input)
{
	int c = get_nonwhite(input), err;
	if (c < 0)
		return c;
	switch (c) {
	case '=':
	case ',':
	case ';':
	case '.':
	case '{':
	case '}':
	case '[':
	case ']':
		return LOCAL_UNEXPECTED_CHAR;
	case '\'':
	case '"':
		err = get_delimstring(string, c, input);
		if (err < 0)
			return err;
		return 1;
	default:
		unget_char(c, input);
		err = get_freestring(string, id, input);
		if (err < 0)
			return err;
		return 0;
	}
}

static int _snd_config_make(snd_config_t **config, char **id, snd_config_type_t type)
{
	snd_config_t *n;
	assert(config);
	n = calloc(1, sizeof(*n));
	if (n == NULL) {
		if (*id) {
			free(*id);
			*id = NULL;
		}
		return -ENOMEM;
	}
	if (id) {
		n->id = *id;
		*id = NULL;
	}
	n->type = type;
	if (type == SND_CONFIG_TYPE_COMPOUND)
		INIT_LIST_HEAD(&n->u.compound.fields);
	*config = n;
	return 0;
}
	

static int _snd_config_make_add(snd_config_t **config, char **id,
				snd_config_type_t type, snd_config_t *father)
{
	snd_config_t *n;
	int err;
	assert(father->type == SND_CONFIG_TYPE_COMPOUND);
	err = _snd_config_make(&n, id, type);
	if (err < 0)
		return err;
	n->father = father;
	list_add_tail(&n->list, &father->u.compound.fields);
	*config = n;
	return 0;
}

static int _snd_config_search(snd_config_t *config, 
			      const char *id, int len, snd_config_t **result)
{
	snd_config_iterator_t i, next;
	snd_config_for_each(i, next, config) {
		snd_config_t *n = snd_config_iterator_entry(i);
		if (len < 0) {
			if (strcmp(n->id, id) != 0)
				continue;
		} else if (strlen(n->id) != (size_t) len ||
			   memcmp(n->id, id, (size_t) len) != 0)
				continue;
		if (result)
			*result = n;
		return 0;
	}
	return -ENOENT;
}

static int parse_value(snd_config_t **_n, snd_config_t *father, input_t *input, char **id, int skip)
{
	snd_config_t *n = *_n;
	char *s;
	int err;

	err = get_string(&s, 0, input);
	if (err < 0)
		return err;
	if (skip) {
		free(s);
		return 0;
	}
	if (err == 0 && ((s[0] >= '0' && s[0] <= '9') || s[0] == '-')) {
		long long i;
		errno = 0;
		err = safe_strtoll(s, &i);
		if (err < 0) {
			double r;
			err = safe_strtod(s, &r);
			if (err >= 0) {
				free(s);
				if (n) {
					if (n->type != SND_CONFIG_TYPE_REAL) {
						SNDERR("%s is not a real", *id);
						return -EINVAL;
					}
				} else {
					err = _snd_config_make_add(&n, id, SND_CONFIG_TYPE_REAL, father);
					if (err < 0)
						return err;
				}
				n->u.real = r;
				*_n = n;
				return 0;
			}
		} else {
			free(s);
			if (n) {
				if (n->type != SND_CONFIG_TYPE_INTEGER && n->type != SND_CONFIG_TYPE_INTEGER64) {
					SNDERR("%s is not an integer", *id);
					return -EINVAL;
				}
			} else {
				if (i <= INT_MAX) 
					err = _snd_config_make_add(&n, id, SND_CONFIG_TYPE_INTEGER, father);
				else
					err = _snd_config_make_add(&n, id, SND_CONFIG_TYPE_INTEGER64, father);
				if (err < 0)
					return err;
			}
			if (n->type == SND_CONFIG_TYPE_INTEGER) 
				n->u.integer = (long) i;
			else 
				n->u.integer64 = i;
			*_n = n;
			return 0;
		}
	}
	if (n) {
		if (n->type != SND_CONFIG_TYPE_STRING) {
			SNDERR("%s is not a string", *id);
			free(s);
			return -EINVAL;
		}
	} else {
		err = _snd_config_make_add(&n, id, SND_CONFIG_TYPE_STRING, father);
		if (err < 0)
			return err;
	}
	if (n->u.string)
		free(n->u.string);
	n->u.string = s;
	*_n = n;
	return 0;
}

static int parse_defs(snd_config_t *father, input_t *input, int skip, int override);
static int parse_array_defs(snd_config_t *farther, input_t *input, int skip, int override);

static int parse_array_def(snd_config_t *father, input_t *input, int idx, int skip, int override)
{
	char static_id[12], *id = NULL;
	int c;
	int err;
	snd_config_t *n = NULL;

	if (!skip) {
		snprintf(static_id, sizeof(static_id), "%i", idx);
		static_id[sizeof(static_id)-1] = '\0';
		id = strdup(static_id);
		if (id == NULL)
			return -ENOMEM;
	}
	c = get_nonwhite(input);
	if (c < 0) {
		err = c;
		goto __end;
	}
	switch (c) {
	case '{':
	case '[':
	{
		char endchr;
		if (!skip) {
			if (n) {
				if (n->type != SND_CONFIG_TYPE_COMPOUND) {
					SNDERR("%s is not a compound", id);
					err = -EINVAL;
					goto __end;
				}
			} else {
				err = _snd_config_make_add(&n, &id, SND_CONFIG_TYPE_COMPOUND, father);
				if (err < 0)
					goto __end;
			}
		}
		if (c == '{') {
			err = parse_defs(n, input, skip, override);
			endchr = '}';
		} else {
			err = parse_array_defs(n, input, skip, override);
			endchr = ']';
		}
		c = get_nonwhite(input);
		if (c < 0) {
			err = c;
			goto __end;
		}
		if (c != endchr) {
			if (n)
				snd_config_delete(n);
			err = LOCAL_UNEXPECTED_CHAR;
			goto __end;
		}
		break;
	}
	default:
		unget_char(c, input);
		err = parse_value(&n, father, input, &id, skip);
		if (err < 0)
			goto __end;
		break;
	}
	err = 0;
      __end:
      	if (id)
      		free(id);
      	return err;
}

static int parse_array_defs(snd_config_t *father, input_t *input, int skip, int override)
{
	int idx = 0;
	while (1) {
		int c = get_nonwhite(input), err;
		if (c < 0)
			return c;
		unget_char(c, input);
		if (c == ']')
			return 0;
		err = parse_array_def(father, input, idx++, skip, override);
		if (err < 0)
			return err;
	}
	return 0;
}

static int parse_def(snd_config_t *father, input_t *input, int skip, int override)
{
	char *id = NULL;
	int c;
	int err;
	snd_config_t *n;
	enum {MERGE_CREATE, MERGE, OVERRIDE, DONT_OVERRIDE} mode;
	while (1) {
		c = get_nonwhite(input);
		if (c < 0)
			return c;
		switch (c) {
		case '+':
			mode = MERGE_CREATE;
			break;
		case '-':
			mode = MERGE;
			break;
		case '?':
			mode = DONT_OVERRIDE;
			break;
		case '!':
			mode = OVERRIDE;
			break;
		default:
			mode = !override ? MERGE_CREATE : OVERRIDE;
			unget_char(c, input);
		}
		err = get_string(&id, 1, input);
		if (err < 0)
			return err;
		c = get_nonwhite(input);
		if (c != '.')
			break;
		if (skip) {
			free(id);
			continue;
		}
		if (_snd_config_search(father, id, -1, &n) == 0) {
			if (mode == DONT_OVERRIDE) {
				skip = 1;
				free(id);
				continue;
			}
			if (mode != OVERRIDE) {
				if (n->type != SND_CONFIG_TYPE_COMPOUND) {
					SNDERR("%s is not a compound", id);
					return -EINVAL;
				}
				n->u.compound.join = 1;
				father = n;
				free(id);
				continue;
			}
			snd_config_delete(n);
		}
		if (mode == MERGE) {
			SNDERR("%s does not exists", id);
			err = -ENOENT;
			goto __end;
		}
		err = _snd_config_make_add(&n, &id, SND_CONFIG_TYPE_COMPOUND, father);
		if (err < 0)
			goto __end;
		n->u.compound.join = 1;
		father = n;
	}
	if (c == '=') {
		c = get_nonwhite(input);
		if (c < 0)
			return c;
	}
	if (!skip) {
		if (_snd_config_search(father, id, -1, &n) == 0) {
			if (mode == DONT_OVERRIDE) {
				skip = 1;
				n = NULL;
			} else if (mode == OVERRIDE) {
				snd_config_delete(n);
				n = NULL;
			}
		} else {
			n = NULL;
			if (mode == MERGE) {
				SNDERR("%s does not exists", id);
				err = -ENOENT;
				goto __end;
			}
		}
	}
	switch (c) {
	case '{':
	case '[':
	{
		char endchr;
		if (!skip) {
			if (n) {
				if (n->type != SND_CONFIG_TYPE_COMPOUND) {
					SNDERR("%s is not a compound", id);
					err = -EINVAL;
					goto __end;
				}
			} else {
				err = _snd_config_make_add(&n, &id, SND_CONFIG_TYPE_COMPOUND, father);
				if (err < 0)
					goto __end;
			}
		}
		if (c == '{') {
			err = parse_defs(n, input, skip, override);
			endchr = '}';
		} else {
			err = parse_array_defs(n, input, skip, override);
			endchr = ']';
		}
		c = get_nonwhite(input);
		if (c != endchr) {
			if (n)
				snd_config_delete(n);
			err = LOCAL_UNEXPECTED_CHAR;
			goto __end;
		}
		break;
	}
	default:
		unget_char(c, input);
		err = parse_value(&n, father, input, &id, skip);
		if (err < 0)
			goto __end;
		break;
	}
	c = get_nonwhite(input);
	switch (c) {
	case ';':
	case ',':
		break;
	default:
		unget_char(c, input);
	}
      __end:
      	if (id)
	      	free(id);
	return err;
}
		
static int parse_defs(snd_config_t *father, input_t *input, int skip, int override)
{
	int c, err;
	while (1) {
		c = get_nonwhite(input);
		if (c < 0)
			return c == LOCAL_UNEXPECTED_EOF ? 0 : c;
		unget_char(c, input);
		if (c == '}')
			return 0;
		err = parse_def(father, input, skip, override);
		if (err < 0)
			return err;
	}
	return 0;
}

static void string_print(char *str, int id, snd_output_t *out)
{
	unsigned char *p = str;
	if (!id) {
		switch (*p) {
		case 0:
			assert(0);
			break;
		case '0' ... '9':
		case '-':
			goto quoted;
		}
	}
	if (!*p) {
		snd_output_puts(out, "''");
		return;
	}
 loop:
	switch (*p) {
	case 0:
		goto nonquoted;
	case 1 ... 31:
	case 127 ... 255:
	case ' ':
	case '=':
	case ';':
	case ',':
	case '.':
	case '{':
	case '}':
	case '\'':
	case '"':
		goto quoted;
	default:
		p++;
		goto loop;
	}
 nonquoted:
	snd_output_puts(out, str);
	return;
 quoted:
	snd_output_putc(out, '\'');
	p = str;
	while (*p) {
		int c;
		c = *p;
		switch (c) {
		case '\n':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 'n');
			break;
		case '\t':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 't');
			break;
		case '\v':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 'v');
			break;
		case '\b':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 'b');
			break;
		case '\r':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 'r');
			break;
		case '\f':
			snd_output_putc(out, '\\');
			snd_output_putc(out, 'f');
			break;
		case '\'':
			snd_output_putc(out, '\\');
			snd_output_putc(out, c);
			break;
		case 32 ... '\'' - 1:
		case '\'' + 1 ... 126:
			snd_output_putc(out, c);
			break;
		default:
			snd_output_printf(out, "\\%04o", c);
			break;
		}
		p++;
	}
	snd_output_putc(out, '\'');
}

static int _snd_config_save_leaves(snd_config_t *config, snd_output_t *out, unsigned int level, unsigned int joins);

static int _snd_config_save_leaf(snd_config_t *n, snd_output_t *out, 
				 unsigned int level)
{
	int err;
	unsigned int k;
	switch (n->type) {
	case SND_CONFIG_TYPE_INTEGER:
		snd_output_printf(out, "%ld", n->u.integer);
		break;
	case SND_CONFIG_TYPE_INTEGER64:
		snd_output_printf(out, "%Ld", n->u.integer64);
		break;
	case SND_CONFIG_TYPE_REAL:
		snd_output_printf(out, "%-16g", n->u.real);
		break;
	case SND_CONFIG_TYPE_STRING:
		string_print(n->u.string, 0, out);
		break;
	case SND_CONFIG_TYPE_POINTER:
		SNDERR("cannot save runtime pointer type");
		return -EINVAL;
	case SND_CONFIG_TYPE_COMPOUND:
		snd_output_putc(out, '{');
		snd_output_putc(out, '\n');
		err = _snd_config_save_leaves(n, out, level + 1, 0);
		if (err < 0)
			return err;
		for (k = 0; k < level; ++k) {
			snd_output_putc(out, '\t');
		}
		snd_output_putc(out, '}');
		break;
	}
	return 0;
}

static void id_print(snd_config_t *n, snd_output_t *out, unsigned int joins)
{
	if (joins > 0) {
		assert(n->father);
		id_print(n->father, out, joins - 1);
		snd_output_putc(out, '.');
	}
	string_print(n->id, 1, out);
}

static int _snd_config_save_leaves(snd_config_t *config, snd_output_t *out, unsigned int level, unsigned int joins)
{
	unsigned int k;
	int err;
	snd_config_iterator_t i, next;
	assert(config && out);
	snd_config_for_each(i, next, config) {
		snd_config_t *n = snd_config_iterator_entry(i);
		if (n->type == SND_CONFIG_TYPE_COMPOUND &&
		    n->u.compound.join) {
			err = _snd_config_save_leaves(n, out, level, joins + 1);
			if (err < 0)
				return err;
			continue;
		}
		for (k = 0; k < level; ++k) {
			snd_output_putc(out, '\t');
		}
		id_print(n, out, joins);
#if 0
		snd_output_putc(out, ' ');
		snd_output_putc(out, '=');
#endif
		snd_output_putc(out, ' ');
		err = _snd_config_save_leaf(n, out, level);
		if (err < 0)
			return err;
#if 0
		snd_output_putc(out, ';');
#endif
		snd_output_putc(out, '\n');
	}
	return 0;
}
#endif


/**
 * \brief Substitute one node to another
 * \param dst Destination node
 * \param src Source node (invalid after call)
 * \return zero if success, 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
 * contents).
 */
int snd_config_substitute(snd_config_t *dst, snd_config_t *src)
{
	assert(dst && src);
	if (dst->type == SND_CONFIG_TYPE_COMPOUND &&
	    src->type == SND_CONFIG_TYPE_COMPOUND) {	/* append */
		snd_config_iterator_t i, next;
		snd_config_for_each(i, next, src) {
			snd_config_t *n = snd_config_iterator_entry(i);
			n->father = dst;
		}
		src->u.compound.fields.next->prev = &dst->u.compound.fields;
		src->u.compound.fields.prev->next = &dst->u.compound.fields;
	} else if (dst->type == SND_CONFIG_TYPE_COMPOUND) {
		int err;
		err = snd_config_delete_compound_members(dst);
		if (err < 0)
			return err;
	}
	if (dst->id)
		free(dst->id);
	dst->id = src->id;
	dst->type = src->type;
	dst->u = src->u;
	free(src);
	return 0;
}

/**
 * \brief Return type of a config node from an ASCII string
 * \param config Config node handle
 * \return node type
 */
int snd_config_get_type_ascii(const char *ascii, snd_config_type_t *type)
{
	assert(ascii && type);
	if (!strcmp(ascii, "integer")) {
		*type = SND_CONFIG_TYPE_INTEGER;
		return 0;
	}
	if (!strcmp(ascii, "integer64")) {
		*type = SND_CONFIG_TYPE_INTEGER64;
		return 0;
	}
	if (!strcmp(ascii, "real")) {
		*type = SND_CONFIG_TYPE_REAL;
		return 0;
	}
	if (!strcmp(ascii, "string")) {
		*type = SND_CONFIG_TYPE_STRING;
		return 0;
	}
	if (!strcmp(ascii, "compound")) {
		*type = SND_CONFIG_TYPE_COMPOUND;
		return 0;
	}
	return -EINVAL;
}

/**
 * \brief Return type of a config node
 * \param config Config node handle
 * \return node type
 */
snd_config_type_t snd_config_get_type(const snd_config_t *config)
{
	return config->type;
}

/**
 * \brief Return id of a config node
 * \param config Config node handle
 * \param value The result id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_id(const snd_config_t *config, const char **id)
{
	assert(config && id);
	*id = config->id;
	return 0;
}

/**
 * \brief Set id of a config node
 * \param config Config node handle
 * \return id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_id(snd_config_t *config, const char *id)
{
	assert(config && id);
	if (config->id)
		free(config->id);
	config->id = strdup(id);
	if (!config->id)
		return -ENOMEM;
	return 0;
}

/**
 * \brief Build a top level config node
 * \param config Returned config node handle pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_top(snd_config_t **config)
{
	assert(config);
	return _snd_config_make(config, 0, SND_CONFIG_TYPE_COMPOUND);
}

static int snd_config_load1(snd_config_t *config, snd_input_t *in, int override)
{
	int err;
	input_t input;
	struct filedesc *fd, *fd_next;
	assert(config && in);
	fd = malloc(sizeof(*fd));
	if (!fd)
		return -ENOMEM;
	fd->name = NULL;
	fd->in = in;
	fd->line = 1;
	fd->column = 0;
	fd->next = NULL;
	input.current = fd;
	input.unget = 0;
	err = parse_defs(config, &input, 0, override);
	fd = input.current;
	if (err < 0) {
		const char *str;
		switch (err) {
		case LOCAL_UNTERMINATED_STRING:
			str = "Unterminated string";
			break;
		case LOCAL_UNTERMINATED_QUOTE:
			str = "Unterminated quote";
			break;
		case LOCAL_UNEXPECTED_CHAR:
			str = "Unexpected char";
			break;
		case LOCAL_UNEXPECTED_EOF:
			str = "Unexpected end of file";
			break;
		default:
			str = strerror(-err);
			break;
		}
		SNDERR("%s:%d:%d:%s", fd->name ? fd->name : "_toplevel_", fd->line, fd->column, str);
		goto _end;
	}
	if (get_char(&input) != LOCAL_UNEXPECTED_EOF) {
		SNDERR("%s:%d:%d:Unexpected }", fd->name ? fd->name : "", fd->line, fd->column);
		err = -EINVAL;
		goto _end;
	}
 _end:
	while (fd->next) {
		fd_next = fd->next;
		snd_input_close(fd->in);
		free(fd->name);
		free(fd);
		fd = fd_next;
	}
	free(fd);
	return err;
}

/**
 * \brief Load a config tree
 * \param config Config top node handle
 * \param in Input handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_load(snd_config_t *config, snd_input_t *in)
{
	return snd_config_load1(config, in, 0);
}

/**
 * \brief Load a config tree and override existing configuration nodes
 * \param config Config top node handle
 * \param in Input handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_load_override(snd_config_t *config, snd_input_t *in)
{
	return snd_config_load1(config, in, 1);
}

/**
 * \brief Add a leaf to a config compound node
 * \param father Config compound node handle
 * \param leaf Leaf config node handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_add(snd_config_t *father, snd_config_t *leaf)
{
	snd_config_iterator_t i, next;
	assert(father && leaf);
	snd_config_for_each(i, next, father) {
		snd_config_t *n = snd_config_iterator_entry(i);
		if (strcmp(leaf->id, n->id) == 0)
			return -EEXIST;
	}
	leaf->father = father;
	list_add_tail(&leaf->list, &father->u.compound.fields);
	return 0;
}

/**
 * \brief Remove a leaf config node from tree
 * \param config Config node handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_remove(snd_config_t *config)
{
	assert(config);
	if (config->father)
		list_del(&config->list);
	config->father = NULL;
	return 0;
}

/**
 * \brief Remove a leaf config node (freeing all the related resources)
 * \param config Config node handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_delete(snd_config_t *config)
{
	assert(config);
	switch (config->type) {
	case SND_CONFIG_TYPE_COMPOUND:
	{
		int err;
		struct list_head *i;
		i = config->u.compound.fields.next;
		while (i != &config->u.compound.fields) {
			struct list_head *nexti = i->next;
			snd_config_t *leaf = snd_config_iterator_entry(i);
			err = snd_config_delete(leaf);
			if (err < 0)
				return err;
			i = nexti;
		}
		break;
	}
	case SND_CONFIG_TYPE_STRING:
		if (config->u.string)
			free(config->u.string);
		break;
	default:
		break;
	}
	if (config->father)
		list_del(&config->list);
	if (config->id)
		free(config->id);
	free(config);
	return 0;
}

/**
 * \brief Remove a compound config node members (freeing all the related resources)
 * \param config Compound config node handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_delete_compound_members(const snd_config_t *config)
{
	int err;
	struct list_head *i;

	assert(config);
	if (config->type != SND_CONFIG_TYPE_COMPOUND)
		return -EINVAL;
	i = config->u.compound.fields.next;
	while (i != &config->u.compound.fields) {
		struct list_head *nexti = i->next;
		snd_config_t *leaf = snd_config_iterator_entry(i);
		err = snd_config_delete(leaf);
		if (err < 0)
			return err;
		i = nexti;
	}
	return 0;
}

/**
 * \brief Build a config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param type Node type
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make(snd_config_t **config, const char *id,
		    snd_config_type_t type)
{
	char *id1;
	assert(config);
	if (id) {
		id1 = strdup(id);
		if (!id1)
			return -ENOMEM;
	} else
		id1 = NULL;
	return _snd_config_make(config, &id1, type);
}

/**
 * \brief Build an integer config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_integer(snd_config_t **config, const char *id)
{
	return snd_config_make(config, id, SND_CONFIG_TYPE_INTEGER);
}

/**
 * \brief Build an integer64 config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_integer64(snd_config_t **config, const char *id)
{
	return snd_config_make(config, id, SND_CONFIG_TYPE_INTEGER64);
}

/**
 * \brief Build a real config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_real(snd_config_t **config, const char *id)
{
	return snd_config_make(config, id, SND_CONFIG_TYPE_REAL);
}

/**
 * \brief Build a string config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_string(snd_config_t **config, const char *id)
{
	return snd_config_make(config, id, SND_CONFIG_TYPE_STRING);
}

/**
 * \brief Build a pointer config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_pointer(snd_config_t **config, const char *id)
{
	return snd_config_make(config, id, SND_CONFIG_TYPE_POINTER);
}

/**
 * \brief Build an empty compound config node
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param join Join flag (checked in snd_config_save to change look)
 * \return 0 on success otherwise a negative error code
 */
int snd_config_make_compound(snd_config_t **config, const char *id,
			     int join)
{
	int err;
	err = snd_config_make(config, id, SND_CONFIG_TYPE_COMPOUND);
	if (err < 0)
		return err;
	(*config)->u.compound.join = join;
	return 0;
}

/**
 * \brief Build an integer config node and use given initial value
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param value Initial value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_imake_integer(snd_config_t **config, const char *id, const long value)
{
	int err;
	
	err = snd_config_make(config, id, SND_CONFIG_TYPE_INTEGER);
	if (err < 0)
		return err;
	(*config)->u.integer = value;
	return 0;
}

/**
 * \brief Build an integer64 config node and use given initial value
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param value Initial value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_imake_integer64(snd_config_t **config, const char *id, const long long value)
{
	int err;
	
	err = snd_config_make(config, id, SND_CONFIG_TYPE_INTEGER64);
	if (err < 0)
		return err;
	(*config)->u.integer64 = value;
	return 0;
}

/**
 * \brief Build a real config node and use given initial value
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param value Initial value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_imake_real(snd_config_t **config, const char *id, const double value)
{
	int err;
	
	err = snd_config_make(config, id, SND_CONFIG_TYPE_REAL);
	if (err < 0)
		return err;
	(*config)->u.real = value;
	return 0;
}

/**
 * \brief Build a string config node and use given initial value
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param value Initial value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_imake_string(snd_config_t **config, const char *id, const char *value)
{
	int err;
	snd_config_t *tmp;
	
	err = snd_config_make(&tmp, id, SND_CONFIG_TYPE_STRING);
	if (err < 0)
		return err;
	if (value) {
		tmp->u.string = strdup(value);
		if (!tmp->u.string) {
			snd_config_delete(tmp);
			return -ENOMEM;
		}
	} else {
		tmp->u.string = NULL;
	}
	*config = tmp;
	return 0;
}

/**
 * \brief Build a pointer config node and use given initial value
 * \param config Returned config node handle pointer
 * \param id Node id
 * \param value Initial value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_imake_pointer(snd_config_t **config, const char *id, const void *value)
{
	int err;
	
	err = snd_config_make(config, id, SND_CONFIG_TYPE_POINTER);
	if (err < 0)
		return err;
	(*config)->u.ptr = value;
	return 0;
}

/**
 * \brief Change the value of an integer config node
 * \param config Config node handle
 * \param value Value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_integer(snd_config_t *config, long value)
{
	assert(config);
	if (config->type != SND_CONFIG_TYPE_INTEGER)
		return -EINVAL;
	config->u.integer = value;
	return 0;
}

/**
 * \brief Change the value of an integer64 config node
 * \param config Config node handle
 * \param value Value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_integer64(snd_config_t *config, long long value)
{
	assert(config);
	if (config->type != SND_CONFIG_TYPE_INTEGER64)
		return -EINVAL;
	config->u.integer64 = value;
	return 0;
}

/**
 * \brief Change the value of a real config node
 * \param config Config node handle
 * \param value Value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_real(snd_config_t *config, double value)
{
	assert(config);
	if (config->type != SND_CONFIG_TYPE_REAL)
		return -EINVAL;
	config->u.real = value;
	return 0;
}

/**
 * \brief Change the value of a string config node
 * \param config Config node handle
 * \param value Value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_string(snd_config_t *config, const char *value)
{
	assert(config);
	if (config->type != SND_CONFIG_TYPE_STRING)
		return -EINVAL;
	if (config->u.string)
		free(config->u.string);
	if (value) {
		config->u.string = strdup(value);
		if (!config->u.string)
			return -ENOMEM;
	} else {
		config->u.string = NULL;
	}
	return 0;
}

/**
 * \brief Change the value of a pointer config node
 * \param config Config node handle
 * \param ptr Value
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_pointer(snd_config_t *config, const void *value)
{
	assert(config);
	if (config->type != SND_CONFIG_TYPE_POINTER)
		return -EINVAL;
	config->u.ptr = value;
	return 0;
}

/**
 * \brief Change the value of a config node
 * \param config Config node handle
 * \param ascii Value in ASCII form
 * \return 0 on success otherwise a negative error code
 */
int snd_config_set_ascii(snd_config_t *config, const char *ascii)
{
	assert(config && ascii);
	switch (config->type) {
	case SND_CONFIG_TYPE_INTEGER:
		{
			long i;
			int err = safe_strtol(ascii, &i);
			if (err < 0)
				return err;
			config->u.integer = i;
		}
		break;
	case SND_CONFIG_TYPE_INTEGER64:
		{
			long long i;
			int err = safe_strtoll(ascii, &i);
			if (err < 0)
				return err;
			config->u.integer64 = i;
		}
		break;
	case SND_CONFIG_TYPE_REAL:
		{
			double d;
			int err = safe_strtod(ascii, &d);
			if (err < 0)
				return err;
			config->u.real = d;
			break;
		}
	case SND_CONFIG_TYPE_STRING:
		{
			char *ptr = realloc(config->u.string, strlen(ascii) + 1);
			if (ptr == NULL)
				return -ENOMEM;
			strcpy(config->u.string, ascii);
		}
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

/**
 * \brief Get the value of an integer config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_integer(const snd_config_t *config, long *ptr)
{
	assert(config && ptr);
	if (config->type != SND_CONFIG_TYPE_INTEGER)
		return -EINVAL;
	*ptr = config->u.integer;
	return 0;
}

/**
 * \brief Get the value of an integer64 config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_integer64(const snd_config_t *config, long long *ptr)
{
	assert(config && ptr);
	if (config->type != SND_CONFIG_TYPE_INTEGER64)
		return -EINVAL;
	*ptr = config->u.integer64;
	return 0;
}

/**
 * \brief Get the value of a real config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_real(const snd_config_t *config, double *ptr)
{
	assert(config && ptr);
	if (config->type != SND_CONFIG_TYPE_REAL)
		return -EINVAL;
	*ptr = config->u.real;
	return 0;
}

/**
 * \brief Get the value of a real or integer config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 *
 * Note: If the config type is integer/integer64, it is converted
 * to the double type on the fly.
 */
int snd_config_get_ireal(const snd_config_t *config, double *ptr)
{
	assert(config && ptr);
	if (config->type == SND_CONFIG_TYPE_REAL)
		*ptr = config->u.real;
	else if (config->type == SND_CONFIG_TYPE_INTEGER)
		*ptr = config->u.integer;
	else if (config->type == SND_CONFIG_TYPE_INTEGER64)
		*ptr = config->u.integer64;
	else
		return -EINVAL;
	return 0;
}

/**
 * \brief Get the value of a string config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_string(const snd_config_t *config, const char **ptr)
{
	assert(config && ptr);
	if (config->type != SND_CONFIG_TYPE_STRING)
		return -EINVAL;
	*ptr = config->u.string;
	return 0;
}

/**
 * \brief Get the value of a pointer config node
 * \param config Config node handle
 * \param ptr Returned value pointer
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_pointer(const snd_config_t *config, const void **ptr)
{
	assert(config && ptr);
	if (config->type != SND_CONFIG_TYPE_POINTER)
		return -EINVAL;
	*ptr = config->u.ptr;
	return 0;
}

/**
 * \brief Get the value in ASCII form
 * \param config Config node handle
 * \param ascii Returned dynamically allocated ASCII string
 * \return 0 on success otherwise a negative error code
 */
int snd_config_get_ascii(const snd_config_t *config, char **ascii)
{
	assert(config && ascii);
	switch (config->type) {
	case SND_CONFIG_TYPE_INTEGER:
		{
			char res[12];
			int err;
			err = snprintf(res, sizeof(res), "%li", config->u.integer);
			if (err < 0 || err == sizeof(res)) {
				assert(0);
				return -ENOMEM;
			}
			*ascii = strdup(res);
		}
		break;
	case SND_CONFIG_TYPE_INTEGER64:
		{
			char res[32];
			int err;
			err = snprintf(res, sizeof(res), "%Li", config->u.integer64);
			if (err < 0 || err == sizeof(res)) {
				assert(0);
				return -ENOMEM;
			}
			*ascii = strdup(res);
		}
		break;
	case SND_CONFIG_TYPE_REAL:
		{
			char res[32];
			int err;
			err = snprintf(res, sizeof(res), "%-16g", config->u.real);
			if (err < 0 || err == sizeof(res)) {
				assert(0);
				return -ENOMEM;
			}
			if (res[0]) {		/* trim the string */
				char *ptr;
				ptr = res + strlen(res) - 1;
				while (ptr != res && *ptr == ' ')
					ptr--;
				if (*ptr != ' ')
					ptr++;
				*ptr = '\0';
			}
			*ascii = strdup(res);
		}
		break;
	case SND_CONFIG_TYPE_STRING:
		if (config->u.string)
			*ascii = strdup(config->u.string);
		else {
			*ascii = NULL;
			return 0;
		}
		break;
	default:
		return -EINVAL;
	}
	if (*ascii == NULL)
		return -ENOMEM;
	return 0;
}

/**
 * \brief Compare the config node id and given ASCII id
 * \param config Config node handle
 * \param id ASCII id
 * \return the same value as result of the strcmp function
 */
int snd_config_test_id(const snd_config_t *config, const char *id)
{
	assert(config && id);
	return strcmp(config->id, id);
}

/**
 * \brief Dump a config tree contents
 * \param config Config node handle
 * \param out Output handle
 * \return 0 on success otherwise a negative error code
 */
int snd_config_save(snd_config_t *config, snd_output_t *out)
{
	assert(config && out);
	if (config->type == SND_CONFIG_TYPE_COMPOUND)
		return _snd_config_save_leaves(config, out, 0, 0);
	else
		return _snd_config_save_leaf(config, out, 0);
}

/*
 *  *** search macros ***
 */

#ifndef DOC_HIDDEN

#define SND_CONFIG_SEARCH(config, key, result, extra_code) \
{ \
	snd_config_t *n; \
	int err; \
	const char *p; \
	assert(config && key); \
	while (1) { \
		if (config->type != SND_CONFIG_TYPE_COMPOUND) \
			return -ENOENT; \
		{ extra_code ; } \
		p = strchr(key, '.'); \
		if (p) { \
			err = _snd_config_search(config, key, p - key, &n); \
			if (err < 0) \
				return err; \
			config = n; \
			key = p + 1; \
		} else \
			return _snd_config_search(config, key, -1, result); \
	} \
}

#define SND_CONFIG_SEARCHA(root, config, key, result, fcn, extra_code) \
{ \
	snd_config_t *n; \
	int err; \
	const char *p; \
	assert(config && key); \
	while (1) { \
		if (config->type != SND_CONFIG_TYPE_COMPOUND) { \
			if (snd_config_get_string(config, &p) < 0) \
				return -ENOENT; \
			err = fcn(root, root, p, &config); \
			if (err < 0) \
				return err; \
		} \
		{ extra_code ; } \
		p = strchr(key, '.'); \
		if (p) { \
			err = _snd_config_search(config, key, p - key, &n); \
			if (err < 0) \
				return err; \
			config = n; \
			key = p + 1; \
		} else \
			return _snd_config_search(config, key, -1, result); \
	} \
}

#define SND_CONFIG_SEARCHV(config, result, fcn) \
{ \
	snd_config_t *n; \
	va_list arg; \
	assert(config); \
	va_start(arg, result); \
	while (1) { \
		const char *k = va_arg(arg, const char *); \
		int err; \
		if (!k) \
			break; \
		err = fcn(config, k, &n); \
		if (err < 0) \
			return err; \
		config = n; \
	} \
	va_end(arg); \
	if (result) \
		*result = n; \
	return 0; \
}

#define SND_CONFIG_SEARCHVA(root, config, result, fcn) \
{ \
	snd_config_t *n; \
	va_list arg; \
	assert(config); \
	va_start(arg, result); \
	while (1) { \
		const char *k = va_arg(arg, const char *); \
		int err; \
		if (!k) \
			break; \
		err = fcn(root, config, k, &n); \
		if (err < 0) \
			return err; \
		config = n; \
	} \
	va_end(arg); \
	if (result) \
		*result = n; \
	return 0; \
}

#define SND_CONFIG_SEARCH_ALIAS(config, base, key, result, fcn1, fcn2) \
{ \
	snd_config_t *res = NULL; \
	int err, first = 1; \
	assert(config && key); \
	do { \
		err = first && base ? -EIO : fcn1(config, config, key, &res); \
		if (err < 0) { \
			if (!base) \
				break; \
			err = fcn2(config, config, &res, base, key, NULL); \
			if (err < 0) \
				break; \
		} \
		first = 0; \
	} while (snd_config_get_string(res, &key) >= 0); \
	if (!res) \
		return err; \
	if (result) \
		*result = res; \
	return 0; \
}

#endif /* DOC_HIDDEN */

/**
 * \brief Search a node inside a config tree
 * \param config Config node handle
 * \param key Dot separated search key
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 */
int snd_config_search(snd_config_t *config, const char *key, snd_config_t **result)
{
	SND_CONFIG_SEARCH(config, key, result, );
}

/**
 * \brief Search a node inside a config tree and expand aliases, excluding the top one
 * \param config Config node handle
 * \param key Dot separated search key
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 */
int snd_config_searcha(snd_config_t *root, snd_config_t *config, const char *key, snd_config_t **result)
{
	SND_CONFIG_SEARCHA(root, config, key, result, snd_config_searcha, );
}

/**
 * \brief Search a node inside a config tree
 * \param config Config node handle
 * \param result Pointer to found node
 * \param ... one or more concatenated dot separated search key
 * \return 0 on success otherwise a negative error code
 */
int snd_config_searchv(snd_config_t *config, snd_config_t **result, ...)
{
	SND_CONFIG_SEARCHV(config, result, snd_config_search);
}

/**
 * \brief Search a node inside a config tree and expand aliases, excluding the top one
 * \param config Config node handle
 * \param result Pointer to found node
 * \param ... one or more concatenated dot separated search key
 * \return 0 on success otherwise a negative error code
 */
int snd_config_searchva(snd_config_t *root, snd_config_t *config, snd_config_t **result, ...)
{
	SND_CONFIG_SEARCHVA(root, config, result, snd_config_searcha);
}

/**
 * \brief Search a node inside a config tree using alias
 * \param config Config node handle
 * \param base Key base (or NULL)
 * \param key Key suffix
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 *
 * First key is tried and if nothing is found is tried base.key.
 * If the value found is a string this is recursively tried in the
 * same way.
 */
int snd_config_search_alias(snd_config_t *config,
			    const char *base, const char *key,
			    snd_config_t **result)
{
	SND_CONFIG_SEARCH_ALIAS(config, base, key, result,
				snd_config_searcha, snd_config_searchva);
}

/**
 * \brief Search a node inside a config tree and expand hooks
 * \param config Config node handle
 * \param key Dot separated search key
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 */
int snd_config_search_hooks(snd_config_t *config, const char *key, snd_config_t **result)
{
	static int snd_config_hooks(snd_config_t *config, snd_config_t *private_data);
	SND_CONFIG_SEARCH(config, key, result, \
					err = snd_config_hooks(config, NULL); \
					if (err < 0) \
						return err; \
			 );
}

/**
 * \brief Search a node inside a config tree and expand aliases and hooks
 * \param config Config node handle
 * \param key Dot separated search key
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 */
int snd_config_searcha_hooks(snd_config_t *root, snd_config_t *config, const char *key, snd_config_t **result)
{
	static int snd_config_hooks(snd_config_t *config, snd_config_t *private_data);
	SND_CONFIG_SEARCHA(root, config, key, result,
					snd_config_searcha_hooks,
					err = snd_config_hooks(config, NULL); \
					if (err < 0) \
						return err; \
			 );
}

/**
 * \brief Search a node inside a config tree and expand hooks and aliases
 * \param config Config node handle
 * \param result Pointer to found node
 * \param ... one or more concatenated dot separated search key
 * \return 0 on success otherwise a negative error code
 */
int snd_config_searchva_hooks(snd_config_t *root, snd_config_t *config,
			      snd_config_t **result, ...)
{
	SND_CONFIG_SEARCHVA(root, config, result, snd_config_searcha_hooks);
}

/**
 * \brief Search a node inside a config tree using alias and expand hooks
 * \param config Config node handle
 * \param base Key base (or NULL)
 * \param key Key suffix
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 *
 * First key is tried and if nothing is found is tried base.key.
 * If the value found is a string this is recursively tried in the
 * same way.
 */
int snd_config_search_alias_hooks(snd_config_t *config,
				  const char *base, const char *key,
				  snd_config_t **result)
{
	SND_CONFIG_SEARCH_ALIAS(config, base, key, result,
				snd_config_searcha_hooks,
				snd_config_searchva_hooks);
}

/** Environment variable containing files list for #snd_config_update */
#define ALSA_CONFIG_PATH_VAR "ALSA_CONFIG_PATH"

/** Default files used by #snd_config_update */
#define ALSA_CONFIG_PATH_DEFAULT DATADIR "/alsa/alsa.conf"

/** \ingroup Config
  * Config top node (global configuration) */
snd_config_t *snd_config = NULL;

struct finfo {
	char *name;
	dev_t dev;
	ino_t ino;
	time_t mtime;
};

struct _snd_config_update {
	unsigned int count;
	struct finfo *finfo;
};

static snd_config_update_t *snd_config_global_update = NULL;

static int snd_config_hooks_call(snd_config_t *root, snd_config_t *config, snd_config_t *private_data)
{
	void *h = NULL;
	snd_config_t *c, *func_conf = NULL;
	char *buf = NULL;
	const char *lib = NULL, *func_name = NULL;
	const char *str;
	int (*func)(snd_config_t *root, snd_config_t *config, snd_config_t **dst, snd_config_t *private_data) = NULL;
	int err;

	err = snd_config_search(config, "func", &c);
	if (err < 0) {
		SNDERR("Field func is missing");
		return err;
	}
	err = snd_config_get_string(c, &str);
	if (err < 0) {
		SNDERR("Invalid type for field func");
		return err;
	}
	err = snd_config_search_definition(root, "hook_func", str, &func_conf);
	if (err >= 0) {
		snd_config_iterator_t i, next;
		if (snd_config_get_type(func_conf) != SND_CONFIG_TYPE_COMPOUND) {
			SNDERR("Invalid type for func %s definition", str);
			goto _err;
		}
		snd_config_for_each(i, next, func_conf) {
			snd_config_t *n = snd_config_iterator_entry(i);
			const char *id = n->id;
			if (strcmp(id, "comment") == 0)
				continue;
			if (strcmp(id, "lib") == 0) {
				err = snd_config_get_string(n, &lib);
				if (err < 0) {
					SNDERR("Invalid type for %s", id);
					goto _err;
				}
				continue;
			}
			if (strcmp(id, "func") == 0) {
				err = snd_config_get_string(n, &func_name);
				if (err < 0) {
					SNDERR("Invalid type for %s", id);
					goto _err;
				}
				continue;
			}
			SNDERR("Unknown field %s", id);
		}
	}
	if (!func_name) {
		int len = 16 + strlen(str) + 1;
		buf = malloc(len);
		snprintf(buf, len, "snd_config_hook_%s", str);
		buf[len-1] = '\0';
		func_name = buf;
	}
	h = snd_dlopen(lib, RTLD_NOW);
	func = h ? snd_dlsym(h, func_name, SND_DLSYM_VERSION(SND_CONFIG_DLSYM_VERSION_HOOK)) : NULL;
	err = 0;
	if (!h) {
		SNDERR("Cannot open shared library %s", lib);
		err = -ENOENT;
	} else if (!func) {
		SNDERR("symbol %s is not defined inside %s", func_name, lib);
		snd_dlclose(h);
		err = -ENXIO;
	}
	_err:
	if (func_conf)
		snd_config_delete(func_conf);
	if (err >= 0) {
		snd_config_t *nroot;
		err = func(root, config, &nroot, private_data);
		if (err < 0)
			SNDERR("function %s returned error: %s", func_name, snd_strerror(err));
		snd_dlclose(h);
		if (err >= 0 && nroot)
			err = snd_config_substitute(root, nroot);
	}
	if (buf)
		free(buf);
	if (err < 0)
		return err;
	return 0;
}

static int snd_config_hooks(snd_config_t *config, snd_config_t *private_data)
{
	snd_config_t *n;
	snd_config_iterator_t i, next;
	int err, hit, idx = 0;

	if ((err = snd_config_search(config, "@hooks", &n)) < 0)
		return 0;
	snd_config_remove(n);
	do {
		hit = 0;
		snd_config_for_each(i, next, n) {
			snd_config_t *n = snd_config_iterator_entry(i);
			const char *id = n->id;
			long i;
			err = safe_strtol(id, &i);
			if (err < 0) {
				SNDERR("id of field %s is not and integer", id);
				err = -EINVAL;
				goto _err;
			}
			if (i == idx) {
				err = snd_config_hooks_call(config, n, private_data);
				if (err < 0)
					return err;
				idx++;
				hit = 1;
			}
		}
	} while (hit);
	err = 0;
       _err:
	snd_config_delete(n);
	return err;
}

/**
 * \brief Load configuration from specified files
 * \param root Configuration root node
 * \param config Configuration node
 * \param dst Destination node
 * \param private_data Private data
 * \return zero if success, otherwise a negative error code
 */
int snd_config_hook_load(snd_config_t *root, snd_config_t *config, snd_config_t **dst, snd_config_t *private_data)
{
	snd_config_t *n;
	snd_config_iterator_t i, next;
	struct finfo *fi = NULL;
	int err, idx = 0, fi_count = 0, errors = 1, hit;

	assert(root && dst);
	if ((err = snd_config_search(config, "errors", &n)) >= 0) {
		char *tmp;
		err = snd_config_get_ascii(n, &tmp);
		if (err < 0)
			return err;
		errors = snd_config_get_bool_ascii(tmp);
		free(tmp);
		if (errors < 0) {
			SNDERR("Invalid bool value in field errors");
			return errors;
		}
	}
	if ((err = snd_config_search(config, "files", &n)) < 0) {
		SNDERR("Unable to find field files in the pre-load section");
		return -EINVAL;
	}
	if ((err = snd_config_expand(n, root, NULL, private_data, &n)) < 0) {
		SNDERR("Unable to expand filenames in the pre-load section");
		return err;
	}
	if (snd_config_get_type(n) != SND_CONFIG_TYPE_COMPOUND) {
		SNDERR("Invalid type for field filenames");
		goto _err;
	}
	snd_config_for_each(i, next, n) {
		snd_config_t *c = snd_config_iterator_entry(i);
		const char *str;
		if ((err = snd_config_get_string(c, &str)) < 0) {
			SNDERR("Field %s is not a string", c->id);
			goto _err;
		}
		fi_count++;
	}
	fi = calloc(fi_count, sizeof(*fi));
	if (fi == NULL) {
		err = -ENOMEM;
		goto _err;
	}
	do {
		hit = 0;
		snd_config_for_each(i, next, n) {
			snd_config_t *n = snd_config_iterator_entry(i);
			const char *id = n->id;
			long i;
			err = safe_strtol(id, &i);
			if (err < 0) {
				SNDERR("id of field %s is not and integer", id);
				err = -EINVAL;
				goto _err;
			}
			if (i == idx) {
				wordexp_t we;
				char *name;
				if ((err = snd_config_get_ascii(n, &name)) < 0)
					goto _err;
				err = wordexp(name, &we, WRDE_NOCMD);
				switch (err) {
				case WRDE_NOSPACE:
					err = -ENOMEM;
					goto _err;
				case 0:
					if (we.we_wordc == 1)
						break;
					/* Fall through */
				default:
					err = -EINVAL;
					goto _err;
				}
				fi[idx].name = strdup(we.we_wordv[0]);
				wordfree(&we);
				free(name);
				if (fi[idx].name == NULL) {
					err = -ENOMEM;
					goto _err;
				}
				idx++;
				hit = 1;
			}
		}
	} while (hit);
	for (idx = 0; idx < fi_count; idx++) {
		snd_input_t *in;
		if (!errors && access(fi[idx].name, R_OK) < 0)
			continue;
		err = snd_input_stdio_open(&in, fi[idx].name, "r");
		if (err >= 0) {
			err = snd_config_load(root, in);
			snd_input_close(in);
			if (err < 0) {
				SNDERR("%s may be old or corrupted: consider to remove or fix it", fi[idx].name);
				goto _err;
			}
		} else {
			SNDERR("cannot access file %s", fi[idx].name);
		}
	}
	*dst = NULL;
	err = 0;
       _err:
	for (idx = 0; idx < fi_count; idx++)
       		if (fi[idx].name)
       			free(fi[idx].name);
       	if (fi)
       		free(fi);
	snd_config_delete(n);
	return err;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(snd_config_hook_load, SND_CONFIG_DLSYM_VERSION_HOOK);
#endif

#ifndef DOC_HIDDEN
int snd_determine_driver(int card, char **driver);
#endif

/**
 * \brief Load configuration for all present cards
 * \param root Configuration root node
 * \param config Configuration node
 * \param dst Destination node
 * \param private_data Private data
 * \return zero if success, otherwise a negative error code
 */
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 ATTRIBUTE_UNUSED)
{
	int card = -1, err;
	
	do {
		err = snd_card_next(&card);
		if (err < 0)
			return err;
		if (card >= 0) {
			snd_config_t *n, *private_data = NULL;
			const char *driver;
			char *fdriver = NULL;
			err = snd_determine_driver(card, &fdriver);
			if (err < 0)
				return err;
			if (snd_config_search(root, fdriver, &n) >= 0) {
				if (snd_config_get_string(n, &driver) < 0)
					continue;
				while (1) {
					char *s = strchr(driver, '.');
					if (s == NULL)
						break;
					driver = s + 1;
				}
				if (snd_config_search(root, driver, &n) >= 0)
					continue;
			} else {
				driver = fdriver;
			}
			err = snd_config_imake_string(&private_data, "string", driver);
			if (err < 0)
				goto __err;
			err = snd_config_hook_load(root, config, &n, private_data);
		      __err:
			if (private_data)
				snd_config_delete(private_data);
			if (fdriver)
				free(fdriver);
			if (err < 0)
				return err;
		}
	} while (card >= 0);
	*dst = NULL;
	return 0;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(snd_config_hook_load_for_all_cards, SND_CONFIG_DLSYM_VERSION_HOOK);
#endif

/** 
 * \brief Update #snd_config rereading (if needed) configuration files.
 * \param top Top node
 * \param update Private update information
 * \param cfgs Configuration files in list delimited with ':', if NULL -> default global 
 *             configuration file is used - "/usr/share/alsa/alsa.conf".
 * \return non-negative value on success, otherwise a negative error code
 * \retval 0 no action is needed
 * \retval 1 tree has been rebuild
 *
 * The global configuration files are specified in environment variable ALSA_CONFIG_PATH.
 *
 * Warning: If config tree is reread all the string pointer and config 
 * node handle previously obtained from this tree become invalid.
 */
int snd_config_update_r(snd_config_t **_top, snd_config_update_t **_update, const char *cfgs)
{
	int err;
	const char *configs, *c;
	unsigned int k;
	wordexp_t we;
	size_t l;
	snd_config_update_t *local;
	snd_config_update_t *update;
	snd_config_t *top;
	
	assert(_top && _update);
	top = *_top;
	update = *_update;
	configs = cfgs;
	if (!configs) {
		configs = getenv(ALSA_CONFIG_PATH_VAR);
		if (!configs)
			configs = ALSA_CONFIG_PATH_DEFAULT;
	}
	for (k = 0, c = configs; (l = strcspn(c, ": ")) > 0; ) {
		c += l;
		k++;
		if (!*c)
			break;
		c++;
	}
	if (k == 0) {
		local = NULL;
		goto _reread;
	}
	local = (snd_config_update_t *)calloc(1, sizeof(snd_config_update_t));
	if (!local)
		return -ENOMEM;
	local->count = k;
	local->finfo = calloc(local->count, sizeof(struct finfo));
	if (!local->finfo) {
		free(local);
		return -ENOMEM;
	}
	for (k = 0, c = configs; (l = strcspn(c, ": ")) > 0; ) {
		char name[l + 1];
		memcpy(name, c, l);
		name[l] = 0;
		err = wordexp(name, &we, WRDE_NOCMD);
		switch (err) {
		case WRDE_NOSPACE:
			err = -ENOMEM;
			goto _end;
		case 0:
			if (we.we_wordc == 1)
				break;
			/* Fall through */
		default:
			err = -EINVAL;
			goto _end;
		}
		local->finfo[k].name = strdup(we.we_wordv[0]);
		wordfree(&we);
		if (!local->finfo[k].name) {
			err = -ENOMEM;
			goto _end;
		}
		c += l;
		k++;
		if (!*c)
			break;
		c++;
	}
	for (k = 0; k < local->count; ++k) {
		struct stat st;
		struct finfo *lf = &local->finfo[k];
		if (stat(lf->name, &st) >= 0) {
			lf->dev = st.st_dev;
			lf->ino = st.st_ino;
			lf->mtime = st.st_mtime;
		} else {
			memmove(&local->finfo[k], &local->finfo[k+1], sizeof(struct finfo) * (local->count - k - 1));
			k--;
			local->count--;
		}
	}
	if (!update)
		goto _reread;
	if (local->count != update->count)
		goto _reread;
	for (k = 0; k < local->count; ++k) {
		struct finfo *lf = &local->finfo[k];
		struct finfo *uf = &update->finfo[k];
		if (strcmp(lf->name, uf->name) != 0 ||
		    lf->dev != uf->dev ||
		    lf->ino != uf->ino ||
		    lf->mtime != uf->mtime)
			goto _reread;
	}
	err = 0;

 _end:
	if (err < 0) {
		if (top) {
			snd_config_delete(top);
			*_top = NULL;
		}
		if (update) {
			snd_config_update_free(update);
			*_update = NULL;
		}
	}
	if (local)
		snd_config_update_free(local);
	return err;

 _reread:
 	*_top = NULL;
 	*_update = NULL;
 	if (update) {
 		snd_config_update_free(update);
 		update = NULL;
 	}
	if (top) {
		snd_config_delete(top);
		top = NULL;
	}
	err = snd_config_top(&top);
	if (err < 0)
		goto _end;
	if (!local)
		goto _skip;
	for (k = 0; k < local->count; ++k) {
		snd_input_t *in;
		err = snd_input_stdio_open(&in, local->finfo[k].name, "r");
		if (err >= 0) {
			err = snd_config_load(top, in);
			snd_input_close(in);
			if (err < 0) {
				SNDERR("%s may be old or corrupted: consider to remove or fix it", local->finfo[k].name);
				goto _end;
			}
		} else {
			SNDERR("cannot access file %s", local->finfo[k].name);
		}
	}
 _skip:
	err = snd_config_hooks(top, NULL);
	if (err < 0) {
		SNDERR("hooks failed, removing configuration");
		goto _end;
	}
	*_top = top;
	*_update = local;
	return 1;
}

static pthread_mutex_t snd_config_update_mutex = PTHREAD_MUTEX_INITIALIZER;

/** 
 * \brief Update #snd_config rereading (if needed) global configuration files.
 * \return non-negative value on success, otherwise a negative error code
 * \retval 0 no action is needed
 * \retval 1 tree has been rebuild
 *
 * The global configuration files are specified in environment variable ALSA_CONFIG_PATH.
 * If it is not set the default value is "/usr/share/alsa/alsa.conf".
 *
 * Warning: If config tree is reread all the string pointer and config 
 * node handle previously obtained from this tree become invalid.
 */
int snd_config_update(void)
{
	int err;

	pthread_mutex_lock(&snd_config_update_mutex);
	err = snd_config_update_r(&snd_config, &snd_config_global_update, NULL);
	pthread_mutex_unlock(&snd_config_update_mutex);
	return err;
}

/** 
 * \brief Free private update structure
 * \param update private update structure to free
 * \return non-negative value on success, otherwise a negative error code
 */
int snd_config_update_free(snd_config_update_t *update)
{
	unsigned int k;

	assert(update);
	assert(update->count > 0 && update->finfo);
	for (k = 0; k < update->count; k++)
		free(update->finfo[k].name);
	if (update->finfo)
		free(update->finfo);
	free(update);
	return 0;
}

/** 
 * \brief Free global configuration in snd_config
 * \return non-negative value on success, otherwise a negative error code
 */
int snd_config_update_free_global(void)
{
	pthread_mutex_lock(&snd_config_update_mutex);
	if (snd_config)
		snd_config_delete(snd_config);
	snd_config = NULL;
	if (snd_config_global_update)
		snd_config_update_free(snd_config_global_update);
	snd_config_global_update = NULL;
	pthread_mutex_unlock(&snd_config_update_mutex);
	return 0;
}

/**
 * \brief Return an iterator pointing to first leaf of a compound config node
 * \param node Config node handle
 * \return iterator value for first leaf
 */
const snd_config_iterator_t snd_config_iterator_first(const snd_config_t *node)
{
	assert(node->type == SND_CONFIG_TYPE_COMPOUND);
	return node->u.compound.fields.next;
}

/**
 * \brief Return an iterator pointing to next leaf
 * \param iterator Config node iterator
 * \return iterator value for next leaf
 */
const snd_config_iterator_t snd_config_iterator_next(const snd_config_iterator_t iterator)
{
	return iterator->next;
}

/**
 * \brief Return an iterator pointing past the last leaf of a compound config node
 * \param node Config node handle
 * \return iterator value for end
 */
const snd_config_iterator_t snd_config_iterator_end(const snd_config_t *node)
{
	assert(node->type == SND_CONFIG_TYPE_COMPOUND);
	return (const snd_config_iterator_t)&node->u.compound.fields;
}

/**
 * \brief Return the node handle pointed by iterator
 * \param iterator Config node iterator
 * \return config node handle
 */
snd_config_t *snd_config_iterator_entry(const snd_config_iterator_t iterator)
{
	return list_entry(iterator, snd_config_t, list);
}

#ifndef DOC_HIDDEN
typedef enum _snd_config_walk_pass {
	SND_CONFIG_WALK_PASS_PRE,
	SND_CONFIG_WALK_PASS_POST,
	SND_CONFIG_WALK_PASS_LEAF,
} snd_config_walk_pass_t;
#endif

/* Return 1 if node needs to be attached to father */
/* Return 2 if compound is replaced with standard node */
#ifndef DOC_HIDDEN
typedef int (*snd_config_walk_callback_t)(snd_config_t *src,
					  snd_config_t *root,
					  snd_config_t **dst,
					  snd_config_walk_pass_t pass,
					  snd_config_t *private_data);
#endif

static int snd_config_walk(snd_config_t *src,
			   snd_config_t *root,
			   snd_config_t **dst, 
			   snd_config_walk_callback_t callback,
			   snd_config_t *private_data)
{
	int err;
	snd_config_iterator_t i, next;

	switch (snd_config_get_type(src)) {
	case SND_CONFIG_TYPE_COMPOUND:
		err = callback(src, root, dst, SND_CONFIG_WALK_PASS_PRE, private_data);
		if (err <= 0)
			return err;
		snd_config_for_each(i, next, src) {
			snd_config_t *s = snd_config_iterator_entry(i);
			snd_config_t *d = NULL;

			err = snd_config_walk(s, root, (dst && *dst) ? &d : NULL,
					      callback, private_data);
			if (err < 0)
				goto _error;
			if (err && d) {
				err = snd_config_add(*dst, d);
				if (err < 0)
					goto _error;
			}
		}
		err = callback(src, root, dst, SND_CONFIG_WALK_PASS_POST, private_data);
		if (err <= 0) {
		_error:
			if (dst && *dst)
				snd_config_delete(*dst);
		}
		break;
	default:
		err = callback(src, root, dst, SND_CONFIG_WALK_PASS_LEAF, private_data);
		break;
	}
	return err;
}

static int _snd_config_copy(snd_config_t *src,
			    snd_config_t *root ATTRIBUTE_UNUSED,
			    snd_config_t **dst,
			    snd_config_walk_pass_t pass,
			    snd_config_t *private_data ATTRIBUTE_UNUSED)
{
	int err;
	const char *id = src->id;
	snd_config_type_t type = snd_config_get_type(src);
	switch (pass) {
	case SND_CONFIG_WALK_PASS_PRE:
		err = snd_config_make_compound(dst, id, src->u.compound.join);
		if (err < 0)
			return err;
		break;
	case SND_CONFIG_WALK_PASS_LEAF:
		err = snd_config_make(dst, id, type);
		if (err < 0)
			return err;
		switch (type) {
		case SND_CONFIG_TYPE_INTEGER:
		{
			long v;
			err = snd_config_get_integer(src, &v);
			assert(err >= 0);
			snd_config_set_integer(*dst, v);
			break;
		}
		case SND_CONFIG_TYPE_INTEGER64:
		{
			long long v;
			err = snd_config_get_integer64(src, &v);
			assert(err >= 0);
			snd_config_set_integer64(*dst, v);
			break;
		}
		case SND_CONFIG_TYPE_REAL:
		{
			double v;
			err = snd_config_get_real(src, &v);
			assert(err >= 0);
			snd_config_set_real(*dst, v);
			break;
		}
		case SND_CONFIG_TYPE_STRING:
		{
			const char *s;
			err = snd_config_get_string(src, &s);
			assert(err >= 0);
			err = snd_config_set_string(*dst, s);
			if (err < 0)
				return err;
			break;
		}
		default:
			assert(0);
		}
		break;
	default:
		break;
	}
	return 1;
}

/**
 * \brief Return the copy of configuration
 * \param dst Destination configuration handle
 * \return src Source configuration handle
 */
int snd_config_copy(snd_config_t **dst,
		    snd_config_t *src)
{
	return snd_config_walk(src, NULL, dst, _snd_config_copy, NULL);
}

static int _snd_config_expand(snd_config_t *src,
			      snd_config_t *root ATTRIBUTE_UNUSED,
			      snd_config_t **dst,
			      snd_config_walk_pass_t pass,
			      snd_config_t *private_data)
{
	int err;
	const char *id = src->id;
	snd_config_type_t type = snd_config_get_type(src);
	switch (pass) {
	case SND_CONFIG_WALK_PASS_PRE:
	{
		if (strcmp(id, "@args") == 0)
			return 0;
		err = snd_config_make_compound(dst, id, src->u.compound.join);
		if (err < 0)
			return err;
		break;
	}
	case SND_CONFIG_WALK_PASS_LEAF:
		switch (type) {
		case SND_CONFIG_TYPE_INTEGER:
		{
			long v;
			err = snd_config_get_integer(src, &v);
			assert(err >= 0);
			err = snd_config_imake_integer(dst, id, v);
			if (err < 0)
				return err;
			break;
		}
		case SND_CONFIG_TYPE_INTEGER64:
		{
			long long v;
			err = snd_config_get_integer64(src, &v);
			assert(err >= 0);
			err = snd_config_imake_integer64(dst, id, v);
			if (err < 0)
				return err;
			break;
		}
		case SND_CONFIG_TYPE_REAL:
		{
			double v;
			err = snd_config_get_real(src, &v);
			assert(err >= 0);
			err = snd_config_imake_real(dst, id, v);
			if (err < 0)
				return err;
			break;
		}
		case SND_CONFIG_TYPE_STRING:
		{
			const char *s;
			snd_config_t *val;
			snd_config_t *vars = private_data;
			snd_config_get_string(src, &s);
			if (*s == '$') {
				s++;
				if (snd_config_search(vars, s, &val) < 0)
					return 0;
				err = snd_config_copy(dst, val);
				if (err < 0)
					return err;
				err = snd_config_set_id(*dst, id);
				if (err < 0) {
					snd_config_delete(*dst);
					return err;
				}
			} else {
				err = snd_config_imake_string(dst, id, s);
				if (err < 0)
					return err;
			}
			break;
		}
		default:
			assert(0);
		}
		break;
	default:
		break;
	}
	return 1;
}

static int _snd_config_evaluate(snd_config_t *src,
				snd_config_t *root,
				snd_config_t **dst ATTRIBUTE_UNUSED,
				snd_config_walk_pass_t pass,
				snd_config_t *private_data)
{
	int err;
	if (pass == SND_CONFIG_WALK_PASS_PRE) {
		char *buf = NULL;
		const char *lib = NULL, *func_name = NULL;
		const char *str;
		int (*func)(snd_config_t **dst, snd_config_t *root,
			    snd_config_t *src, snd_config_t *private_data) = NULL;
		void *h = NULL;
		snd_config_t *c, *func_conf = NULL;
		err = snd_config_search(src, "@func", &c);
		if (err < 0)
			return 1;
		err = snd_config_get_string(c, &str);
		if (err < 0) {
			SNDERR("Invalid type for @func");
			return err;
		}
		err = snd_config_search_definition(root, "func", str, &func_conf);
		if (err >= 0) {
			snd_config_iterator_t i, next;
			if (snd_config_get_type(func_conf) != SND_CONFIG_TYPE_COMPOUND) {
				SNDERR("Invalid type for func %s definition", str);
				goto _err;
			}
			snd_config_for_each(i, next, func_conf) {
				snd_config_t *n = snd_config_iterator_entry(i);
				const char *id = n->id;
				if (strcmp(id, "comment") == 0)
					continue;
				if (strcmp(id, "lib") == 0) {
					err = snd_config_get_string(n, &lib);
					if (err < 0) {
						SNDERR("Invalid type for %s", id);
						goto _err;
					}
					continue;
				}
				if (strcmp(id, "func") == 0) {
					err = snd_config_get_string(n, &func_name);
					if (err < 0) {
						SNDERR("Invalid type for %s", id);
						goto _err;
					}
					continue;
				}
				SNDERR("Unknown field %s", id);
			}
		}
		if (!func_name) {
			int len = 9 + strlen(str) + 1;
			buf = malloc(len);
			snprintf(buf, len, "snd_func_%s", str);
			buf[len-1] = '\0';
			func_name = buf;
		}
		h = snd_dlopen(lib, RTLD_NOW);
		if (h)
			func = snd_dlsym(h, func_name, SND_DLSYM_VERSION(SND_CONFIG_DLSYM_VERSION_EVALUATE));
		err = 0;
		if (!h) {
			SNDERR("Cannot open shared library %s", lib);
			err = -ENOENT;
			goto _errbuf;
		} else if (!func) {
			SNDERR("symbol %s is not defined inside %s", func_name, lib);
			snd_dlclose(h);
			err = -ENXIO;
			goto _errbuf;
		}
	       _err:
		if (func_conf)
			snd_config_delete(func_conf);
		if (err >= 0) {
			snd_config_t *eval;
			err = func(&eval, root, src, private_data);
			if (err < 0)
				SNDERR("function %s returned error: %s", func_name, snd_strerror(err));
			snd_dlclose(h);
			if (err >= 0 && eval) {
				/* substitute merges compound members */
				/* we don't want merging at all */
				err = snd_config_delete_compound_members(src);
				if (err >= 0)
					err = snd_config_substitute(src, eval);
			}
		}
	       _errbuf:
		if (buf)
			free(buf);
		if (err < 0)
			return err;
		return 0;
	}
	return 1;
}

/**
 * \brief Evaluate a config node in runtime
 * \param config source configuration node
 * \param root root of the source configuration
 * \param private_data private data for runtime evaluation
 * \param result result configuration node
 * \return zero if success, otherwise a negative error code
 */
int snd_config_evaluate(snd_config_t *config, snd_config_t *root,
		        snd_config_t *private_data, snd_config_t **result)
{
	/* FIXME: Only in place evaluation is currently implemented */
	assert(result == NULL);
	return snd_config_walk(config, root, result, _snd_config_evaluate, private_data);
}

static int load_defaults(snd_config_t *subs, snd_config_t *defs)
{
	snd_config_iterator_t d, dnext;
	snd_config_for_each(d, dnext, defs) {
		snd_config_t *def = snd_config_iterator_entry(d);
		snd_config_iterator_t f, fnext;
		if (snd_config_get_type(def) != SND_CONFIG_TYPE_COMPOUND)
			continue;
		snd_config_for_each(f, fnext, def) {
			snd_config_t *fld = snd_config_iterator_entry(f);
			const char *id = fld->id;
			if (strcmp(id, "type") == 0)
				continue;
			if (strcmp(id, "default") == 0) {
				snd_config_t *deflt;
				int err;
				err = snd_config_copy(&deflt, fld);
				if (err < 0)
					return err;
				err = snd_config_set_id(deflt, def->id);
				if (err < 0) {
					snd_config_delete(deflt);
					return err;
				}
				err = snd_config_add(subs, deflt);
				if (err < 0) {
					snd_config_delete(deflt);
					return err;
				}
				continue;
			}
			SNDERR("Unknown field %s", id);
			return -EINVAL;
		}
	}
	return 0;
}

static void skip_blank(const char **ptr)
{
	while (1) {
		switch (**ptr) {
		case ' ':
		case '\f':
		case '\t':
		case '\n':
		case '\r':
			break;
		default:
			return;
		}
		(*ptr)++;
	}
}

static int parse_char(const char **ptr)
{
	int c;
	assert(**ptr == '\\');
	(*ptr)++;
	c = **ptr;
	switch (c) {
	case 'n':
		c = '\n';
		break;
	case 't':
		c = '\t';
		break;
	case 'v':
		c = '\v';
		break;
	case 'b':
		c = '\b';
		break;
	case 'r':
		c = '\r';
		break;
	case 'f':
		c = '\f';
		break;
	case '0' ... '7':
	{
		int num = c - '0';
		int i = 1;
		(*ptr)++;
		do {
			c = **ptr;
			if (c < '0' || c > '7')
				break;
			num = num * 8 + c - '0';
			i++;
			(*ptr)++;
		} while (i < 3);
		return num;
	}
	default:
		break;
	}
	(*ptr)++;
	return c;
}

static int parse_id(const char **ptr)
{
	if (!**ptr)
		return -EINVAL;
	while (1) {
		switch (**ptr) {
		case '\f':
		case '\t':
		case '\n':
		case '\r':
		case ',':
		case '=':
		case '\0':
			return 0;
		default:
			break;
		}
		(*ptr)++;
	}
}

static int parse_string(const char **ptr, char **val)
{
	const size_t bufsize = 256;
	char _buf[bufsize];
	char *buf = _buf;
	size_t alloc = bufsize;
	char delim = **ptr;
	size_t idx = 0;
	(*ptr)++;
	while (1) {
		int c = **ptr;
		switch (c) {
		case '\0':
			SNDERR("Unterminated string");
			return -EINVAL;
		case '\\':
			c = parse_char(ptr);
			if (c < 0)
				return c;
			break;
		default:
			(*ptr)++;
			if (c == delim) {
				*val = malloc(idx + 1);
				if (!*val)
					return -ENOMEM;
				memcpy(*val, buf, idx);
				(*val)[idx] = 0;
				if (alloc > bufsize)
					free(buf);
				return 0;
			}
		}
		if (idx >= alloc) {
			size_t old_alloc = alloc;
			alloc *= 2;
			if (old_alloc == bufsize) {
				buf = malloc(alloc);
				memcpy(buf, _buf, old_alloc);
			} else {
				buf = realloc(buf, alloc);
			}
			if (!buf)
				return -ENOMEM;
		}
		buf[idx++] = c;
	}
}
				

/* Parse var=val or val */
static int parse_arg(const char **ptr, unsigned int *varlen, char **val)
{
	const char *str;
	int err, vallen;
	skip_blank(ptr);
	str = *ptr;
	if (*str == '"' || *str == '\'') {
		err = parse_string(ptr, val);
		if (err < 0)
			return err;
		*varlen = 0;
		return 0;
	}
	err = parse_id(ptr);
	if (err < 0)
		return err;
	vallen = *ptr - str;
	skip_blank(ptr);
	if (**ptr != '=') {
		*varlen = 0;
		goto _value;
	}
	*varlen = vallen;
	(*ptr)++;
	skip_blank(ptr);
	str = *ptr;
	if (*str == '"' || *str == '\'') {
		err = parse_string(ptr, val);
		if (err < 0)
			return err;
		return 0;
	}
	err = parse_id(ptr);
	if (err < 0)
		return err;
	vallen = *ptr - str;
 _value:
	*val = malloc(vallen + 1);
	if (!*val)
		return -ENOMEM;
	memcpy(*val, str, vallen);
	(*val)[vallen] = 0;
	return 0;
}


/* val1, val2, ...
 * var1=val1,var2=val2,...
 * { conf syntax }
 */
static int parse_args(snd_config_t *subs, const char *str, snd_config_t *defs)
{
	int err;
	int arg = 0;
	if (str == NULL)
		return 0;
	skip_blank(&str);
	if (!*str)
		return 0;
	if (*str == '{') {
		int len = strlen(str);
		snd_input_t *input;
		snd_config_iterator_t i, next;
		while (1) {
			switch (str[--len]) {
			case ' ':
			case '\f':
			case '\t':
			case '\n':
			case '\r':
				continue;
			default:
				break;
			}
			break;
		}
		if (str[len] != '}')
			return -EINVAL;
		err = snd_input_buffer_open(&input, str + 1, len - 1);
		if (err < 0)
			return err;
		err = snd_config_load_override(subs, input);
		snd_input_close(input);
		if (err < 0)
			return err;
		snd_config_for_each(i, next, subs) {
			snd_config_t *n = snd_config_iterator_entry(i);
			snd_config_t *d;
			const char *id = n->id;
			err = snd_config_search(defs, id, &d);
			if (err < 0) {
				SNDERR("Unknown parameter %s", id);
				return err;
			}
		}
		return 0;
	}
	
	while (1) {
		char buf[256];
		const char *var = buf;
		unsigned int varlen;
		snd_config_t *def, *sub, *typ;
		const char *new = str;
		const char *tmp;
		char *val;
		err = parse_arg(&new, &varlen, &val);
		if (err < 0)
			goto _err;
		if (varlen > 0) {
			assert(varlen < sizeof(buf));
			memcpy(buf, str, varlen);
			buf[varlen] = 0;
		} else {
			sprintf(buf, "%d", arg);
		}
		err = snd_config_search_alias(defs, NULL, var, &def);
		if (err < 0) {
			SNDERR("Unknown parameter %s", var);
			goto _err;
		}
		if (snd_config_get_type(def) != SND_CONFIG_TYPE_COMPOUND) {
			SNDERR("Parameter %s definition is not correct", var);
			err = -EINVAL;
			goto _err;
		}
		var = def->id;
		err = snd_config_search(subs, var, &sub);
		if (err >= 0)
			snd_config_delete(sub);
		err = snd_config_search(def, "type", &typ);
		if (err < 0) {
		_invalid_type:
			SNDERR("Parameter %s definition is missing a valid type info", var);
			goto _err;
		}
		err = snd_config_get_string(typ, &tmp);
		if (err < 0)
			goto _invalid_type;
		if (strcmp(tmp, "integer") == 0) {
			long v;
			err = snd_config_make(&sub, var, SND_CONFIG_TYPE_INTEGER);
			if (err < 0)
				goto _err;
			err = safe_strtol(val, &v);
			if (err < 0) {
				SNDERR("Parameter %s must be an integer", var);
				goto _err;
			}
			err = snd_config_set_integer(sub, v);
			if (err < 0)
				goto _err;
		} else if (strcmp(tmp, "integer64") == 0) {
			long long v;
			err = snd_config_make(&sub, var, SND_CONFIG_TYPE_INTEGER64);
			if (err < 0)
				goto _err;
			err = safe_strtoll(val, &v);
			if (err < 0) {
				SNDERR("Parameter %s must be an integer", var);
				goto _err;
			}
			err = snd_config_set_integer64(sub, v);
			if (err < 0)
				goto _err;
		} else if (strcmp(tmp, "real") == 0) {
			double v;
			err = snd_config_make(&sub, var, SND_CONFIG_TYPE_REAL);
			if (err < 0)
				goto _err;
			err = safe_strtod(val, &v);
			if (err < 0) {
				SNDERR("Parameter %s must be a real", var);
				goto _err;
			}
			err = snd_config_set_real(sub, v);
			if (err < 0)
				goto _err;
		} else if (strcmp(tmp, "string") == 0) {
			err = snd_config_make(&sub, var, SND_CONFIG_TYPE_STRING);
			if (err < 0)
				goto _err;
			err = snd_config_set_string(sub, val);
			if (err < 0)
				goto _err;
		} else {
			err = -EINVAL;
			goto _invalid_type;
		}
		err = snd_config_set_id(sub, var);
		if (err < 0)
			goto _err;
		err = snd_config_add(subs, sub);
		if (err < 0) {
		_err:
			free(val);
			return err;
		}
		free(val);
		if (!*new)
			break;
		if (*new != ',')
			return -EINVAL;
		str = new + 1;
		arg++;
	}
	return 0;
}

/**
 * \brief Expand a node applying arguments and functions
 * \param config Config node handle
 * \param root Root config node handle
 * \param args Arguments string (optional)
 * \param private_data Private data for functions
 * \param result Pointer to found node
 * \return 0 on success otherwise a negative error code
 */
int snd_config_expand(snd_config_t *config, snd_config_t *root, const char *args,
		      snd_config_t *private_data, snd_config_t **result)
{
	int err;
	snd_config_t *defs, *subs = NULL, *res;
	err = snd_config_search(config, "@args", &defs);
	if (err < 0) {
		err = snd_config_copy(&res, config);
		if (err < 0)
			return err;
	} else {
		err = snd_config_top(&subs);
		if (err < 0)
			return err;
		err = load_defaults(subs, defs);
		if (err < 0) {
			SNDERR("Load defaults error: %s", snd_strerror(err));
			goto _end;
		}
		err = parse_args(subs, args, defs);
		if (err < 0) {
			SNDERR("Parse arguments error: %s", snd_strerror(err));
			goto _end;
		}
		err = snd_config_evaluate(subs, root, private_data, NULL);
		if (err < 0) {
			SNDERR("Args evaluate error: %s", snd_strerror(err));
			goto _end;
		}
		err = snd_config_walk(config, root, &res, _snd_config_expand, subs);
		if (err < 0) {
			SNDERR("Expand error (walk): %s", snd_strerror(err));
			goto _end;
		}
	}
	err = snd_config_evaluate(res, root, private_data, NULL);
	if (err < 0) {
		SNDERR("Evaluate error: %s", snd_strerror(err));
		snd_config_delete(res);
		goto _end;
	}
	*result = res;
	err = 1;
 _end:
 	if (subs)
		snd_config_delete(subs);
	return err;
}
	
/**
 * \brief Search a definition inside a config tree using alias and expand hooks and arguments
 * \param config Config node handle
 * \param base Implicit key base (or NULL - none)
 * \param key Key suffix
 * \param result Pointer to expanded found node
 * \return 0 on success otherwise a negative error code
 *
 * First key is tried and if nothing is found is tried base.key.
 * If the value found is a string this is recursively tried in the
 * same way.
 */
int snd_config_search_definition(snd_config_t *config,
				 const char *base, const char *name,
				 snd_config_t **result)
{
	snd_config_t *conf;
	char *key;
	const char *args = strchr(name, ':');
	int err;
	if (args) {
		args++;
		key = alloca(args - name);
		memcpy(key, name, args - name - 1);
		key[args - name - 1] = '\0';
	} else {
		key = (char *) name;
	}
	/*
	 *  if key contains dot (.), the implicit base is ignored
	 *  and the key starts from root given by the 'config' parameter
	 */
	err = snd_config_search_alias_hooks(config, strchr(key, '.') ? NULL : base, key, &conf);
	if (err < 0)
		return err;
	return snd_config_expand(conf, config, args, NULL, result);
}


#if 0
/* Not strictly needed, but useful to check for memory leaks */
void _snd_config_end(void) __attribute__ ((destructor));

static void _snd_config_end(void)
{
	int k;
	if (snd_config)
		snd_config_delete(snd_config);
	snd_config = 0;
	for (k = 0; k < files_info_count; ++k)
		free(files_info[k].name);
	free(files_info);
	files_info = NULL;
	files_info_count = 0;
}
#endif