config.h

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Configuration File Parser
 */

#ifndef _ASTERISK_CONFIG_H
#define _ASTERISK_CONFIG_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include "asterisk/utils.h"
#include "asterisk/inline_api.h"

struct ast_config;

struct ast_category;

/*! Options for ast_config_load()
 */
enum {
   /*! Load the configuration, including comments */
   CONFIG_FLAG_WITHCOMMENTS  = (1 << 0),
   /*! On a reload, give us a -1 if the file hasn't changed. */
   CONFIG_FLAG_FILEUNCHANGED = (1 << 1),
   /*! Don't attempt to cache mtime on this config file. */
   CONFIG_FLAG_NOCACHE       = (1 << 2),
   /*! Don't attempt to load from realtime (typically called from a realtime driver dependency) */
   CONFIG_FLAG_NOREALTIME    = (1 << 3),
};

#define  CONFIG_STATUS_FILEMISSING  (void *)0
#define  CONFIG_STATUS_FILEUNCHANGED   (void *)-1
#define  CONFIG_STATUS_FILEINVALID  (void *)-2

/*!
 * \brief Types used in ast_realtime_require_field
 */
typedef enum {
   RQ_INTEGER1,
   RQ_UINTEGER1,
   RQ_INTEGER2,
   RQ_UINTEGER2,
   RQ_INTEGER3,
   RQ_UINTEGER3,
   RQ_INTEGER4,
   RQ_UINTEGER4,
   RQ_INTEGER8,
   RQ_UINTEGER8,
   RQ_CHAR,
   RQ_FLOAT,
   RQ_DATE,
   RQ_DATETIME,
} require_type;

/*! \brief Structure for variables, used for configurations and for channel variables */
struct ast_variable {
   /*! Variable name.  Stored in stuff[] at struct end. */
   const char *name;
   /*! Variable value.  Stored in stuff[] at struct end. */
   const char *value;

   /*! Next node in the list. */
   struct ast_variable *next;

   /*! Filename where variable found.  Stored in stuff[] at struct end. */
   const char *file;

   int lineno;
   int object;    /*!< 0 for variable, 1 for object */
   int blanklines;   /*!< Number of blanklines following entry */
   struct ast_comment *precomments;
   struct ast_comment *sameline;
   struct ast_comment *trailing; /*!< the last object in the list will get assigned any trailing comments when EOF is hit */
   /*!
    * \brief Contents of file, name, and value in that order stuffed here.
    * \note File must be stuffed before name because of ast_include_rename().
    */
   char stuff[0];
};

typedef struct ast_config *config_load_func(const char *database, const char *table, const char *configfile, struct ast_config *config, struct ast_flags flags, const char *suggested_include_file, const char *who_asked);
typedef struct ast_variable *realtime_var_get(const char *database, const char *table, va_list ap);
typedef struct ast_config *realtime_multi_get(const char *database, const char *table, va_list ap);
typedef int realtime_update(const char *database, const char *table, const char *keyfield, const char *entity, va_list ap);
typedef int realtime_update2(const char *database, const char *table, va_list ap);
typedef int realtime_store(const char *database, const char *table, va_list ap);
typedef int realtime_destroy(const char *database, const char *table, const char *keyfield, const char *entity, va_list ap);

/*!
 * \brief Function pointer called to ensure database schema is properly configured for realtime use
 * \since 1.6.1
 */
typedef int realtime_require(const char *database, const char *table, va_list ap);

/*!
 * \brief Function pointer called to clear the database cache and free resources used for such
 * \since 1.6.1
 */
typedef int realtime_unload(const char *database, const char *table);

/*! \brief Configuration engine structure, used to define realtime drivers */
struct ast_config_engine {
   char *name;
   config_load_func *load_func;
   realtime_var_get *realtime_func;
   realtime_multi_get *realtime_multi_func;
   realtime_update *update_func;
   realtime_update2 *update2_func;
   realtime_store *store_func;
   realtime_destroy *destroy_func;
   realtime_require *require_func;
   realtime_unload *unload_func;
   struct ast_config_engine *next;
};

/*!
 * \brief Load a config file
 *
 * \param filename path of file to open.  If no preceding '/' character,
 * path is considered relative to AST_CONFIG_DIR
 * \param who_asked The module which is making this request.
 * \param flags Optional flags:
 * CONFIG_FLAG_WITHCOMMENTS - load the file with comments intact;
 * CONFIG_FLAG_FILEUNCHANGED - check the file mtime and return CONFIG_STATUS_FILEUNCHANGED if the mtime is the same; or
 * CONFIG_FLAG_NOCACHE - don't cache file mtime (main purpose of this option is to save memory on temporary files).
 *
 * \details
 * Create a config structure from a given configuration file.
 *
 * \return an ast_config data structure on success
 * \retval NULL on error
 */
struct ast_config *ast_config_load2(const char *filename, const char *who_asked, struct ast_flags flags);

/*!
 * \brief Load a config file
 *
 * \param filename path of file to open.  If no preceding '/' character,
 * path is considered relative to AST_CONFIG_DIR
 * \param flags Optional flags:
 * CONFIG_FLAG_WITHCOMMENTS - load the file with comments intact;
 * CONFIG_FLAG_FILEUNCHANGED - check the file mtime and return CONFIG_STATUS_FILEUNCHANGED if the mtime is the same; or
 * CONFIG_FLAG_NOCACHE - don't cache file mtime (main purpose of this option is to save memory on temporary files).
 *
 * \details
 * Create a config structure from a given configuration file.
 *
 * \return an ast_config data structure on success
 * \retval NULL on error
 */
#define ast_config_load(filename, flags)  ast_config_load2(filename, AST_MODULE, flags)

/*!
 * \brief Destroys a config
 *
 * \param config pointer to config data structure
 *
 * \details
 * Free memory associated with a given config
 */
void ast_config_destroy(struct ast_config *config);

/*!
 * \brief returns the root ast_variable of a config
 *
 * \param config pointer to an ast_config data structure
 * \param cat name of the category for which you want the root
 *
 * \return the category specified
 */
struct ast_variable *ast_category_root(struct ast_config *config, char *cat);

/*!
 * \brief Sorts categories in a config in the order of a numerical value contained within them.
 *
 * \param config The config structure you wish to sort
 * \param variable Which numerical value you wish to sort by
 * \param descending If true, we sort highest to lowest instead of lowest to highest
 *
 * \details
 * This function will assume a value of 0 for any non-numerical strings and NULL fields.
 */
void ast_config_sort_categories(struct ast_config *config, int descending,
                        int (*comparator)(struct ast_category *p, struct ast_category *q));

/*!
 * \brief Goes through categories
 *
 * \param config Which config structure you wish to "browse"
 * \param prev A pointer to a previous category.
 *
 * \details
 * This function is kind of non-intuitive in it's use.
 * To begin, one passes NULL as the second argument.
 * It will return a pointer to the string of the first category in the file.
 * From here on after, one must then pass the previous usage's return value
 * as the second pointer, and it will return a pointer to the category name
 * afterwards.
 *
 * \retval a category on success
 * \retval NULL on failure/no-more-categories
 */
char *ast_category_browse(struct ast_config *config, const char *prev);

/*!
 * \brief Goes through variables
 *
 * \details
 * Somewhat similar in intent as the ast_category_browse.
 * List variables of config file category
 *
 * \retval ast_variable list on success
 * \retval NULL on failure
 */
struct ast_variable *ast_variable_browse(const struct ast_config *config, const char *category);

/*!
 * \brief given a pointer to a category, return the root variable.
 *
 * \details
 * This is equivalent to ast_variable_browse(), but more efficient if we
 * already have the struct ast_category * (e.g. from ast_category_get())
 */
struct ast_variable *ast_category_first(struct ast_category *cat);

/*!
 * \brief Gets a variable
 *
 * \param config which (opened) config to use
 * \param category category under which the variable lies
 * \param variable which variable you wish to get the data for
 *
 * \details
 * Goes through a given config file in the given category and searches for the given variable
 *
 * \retval The variable value on success
 * \retval NULL if unable to find it.
 */
const char *ast_variable_retrieve(const struct ast_config *config, const char *category, const char *variable);

/*!
 * \brief Retrieve a category if it exists
 *
 * \param config which config to use
 * \param category_name name of the category you're looking for
 *
 * \details
 * This will search through the categories within a given config file for a match.
 *
 * \retval pointer to category if found
 * \retval NULL if not.
 */
struct ast_category *ast_category_get(const struct ast_config *config, const char *category_name);

/*!
 * \brief Check for category duplicates
 *
 * \param config which config to use
 * \param category_name name of the category you're looking for
 *
 * \details
 * This will search through the categories within a given config file for a match.
 *
 * \return non-zero if found
 */
int ast_category_exist(const struct ast_config *config, const char *category_name);

/*!
 * \brief Retrieve realtime configuration
 *
 * \param family which family/config to lookup
 *
 * \details
 * This will use builtin configuration backends to look up a particular
 * entity in realtime and return a variable list of its parameters.
 *
 * \note
 * Unlike the variables in ast_config, the resulting list of variables
 * MUST be freed with ast_variables_destroy() as there is no container.
 *
 * \note
 * The difference between these two calls is that ast_load_realtime excludes
 * fields whose values are NULL, while ast_load_realtime_all loads all columns.
 *
 * \note
 * You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
struct ast_variable *ast_load_realtime(const char *family, ...) attribute_sentinel;
struct ast_variable *ast_load_realtime_all(const char *family, ...) attribute_sentinel;

/*!
 * \brief Release any resources cached for a realtime family
 * \since 1.6.1
 *
 * \param family which family/config to destroy
 *
 * \details
 * Various backends may cache attributes about a realtime data storage
 * facility; on reload, a front end resource may request to purge that cache.
 *
 * \retval 0 If any cache was purged
 * \retval -1 If no cache was found
 */
int ast_unload_realtime(const char *family);

/*!
 * \brief Inform realtime what fields that may be stored
 * \since 1.6.1
 *
 * \param family which family/config is referenced
 *
 * \details
 * This will inform builtin configuration backends that particular fields
 * may be updated during the use of that configuration section.  This is
 * mainly to be used during startup routines, to ensure that various fields
 * exist in the backend.  The backends may take various actions, such as
 * creating new fields in the data store or warning the administrator that
 * new fields may need to be created, in order to ensure proper function.
 *
 * The arguments are specified in groups of 3:  column name, column type,
 * and column size.  The column types are specified as integer constants,
 * defined by the enum require_type.  Note that the size is specified as
 * the number of equivalent character fields that a field may take up, even
 * if a field is otherwise specified as an integer type.  This is due to
 * the fact that some fields have historically been specified as character
 * types, even if they contained integer values.
 *
 * A family should always specify its fields to the minimum necessary
 * requirements to fulfill all possible values (within reason; for example,
 * a timeout value may reasonably be specified as an INTEGER2, with size 5.
 * Even though values above 32767 seconds are possible, they are unlikely
 * to be useful, and we should not complain about that size).
 *
 * \retval 0 Required fields met specified standards
 * \retval -1 One or more fields was missing or insufficient
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
int ast_realtime_require_field(const char *family, ...) attribute_sentinel;

/*!
 * \brief Retrieve realtime configuration
 *
 * \param family which family/config to lookup
 *
 * \details
 * This will use builtin configuration backends to look up a particular
 * entity in realtime and return a variable list of its parameters. Unlike
 * the ast_load_realtime, this function can return more than one entry and
 * is thus stored inside a traditional ast_config structure rather than
 * just returning a linked list of variables.
 *
 * \return An ast_config with one or more results
 * \retval NULL Error or no results returned
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
struct ast_config *ast_load_realtime_multientry(const char *family, ...) attribute_sentinel;

/*!
 * \brief Update realtime configuration
 *
 * \param family which family/config to be updated
 * \param keyfield which field to use as the key
 * \param lookup which value to look for in the key field to match the entry.
 *
 * \details
 * This function is used to update a parameter in realtime configuration space.
 *
 * \return Number of rows affected, or -1 on error.
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
int ast_update_realtime(const char *family, const char *keyfield, const char *lookup, ...) attribute_sentinel;

/*!
 * \brief Update realtime configuration
 *
 * \param family which family/config to be updated
 *
 * \details
 * This function is used to update a parameter in realtime configuration space.
 * It includes the ability to lookup a row based upon multiple key criteria.
 * As a result, this function includes two sentinel values, one to terminate
 * lookup values and the other to terminate the listing of fields to update.
 *
 * \return Number of rows affected, or -1 on error.
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
int ast_update2_realtime(const char *family, ...) attribute_sentinel;

/*!
 * \brief Create realtime configuration
 *
 * \param family which family/config to be created
 *
 * \details
 * This function is used to create a parameter in realtime configuration space.
 *
 * \return Number of rows affected, or -1 on error.
 *
 * \note
 * On the MySQL engine only, for reasons of backwards compatibility, the return
 * value is the insert ID.  This value is nonportable and may be changed in a
 * future version to match the other engines.
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
int ast_store_realtime(const char *family, ...) attribute_sentinel;

/*!
 * \brief Destroy realtime configuration
 *
 * \param family which family/config to be destroyed
 * \param keyfield which field to use as the key
 * \param lookup which value to look for in the key field to match the entry.
 *
 * \details
 * This function is used to destroy an entry in realtime configuration space.
 * Additional params are used as keys.
 *
 * \return Number of rows affected, or -1 on error.
 *
 * \note You should use the constant SENTINEL to terminate arguments, in
 * order to preserve cross-platform compatibility.
 */
int ast_destroy_realtime(const char *family, const char *keyfield, const char *lookup, ...) attribute_sentinel;

/*!
 * \brief Check if realtime engine is configured for family
 * \param family which family/config to be checked
 * \return 1 if family is configured in realtime and engine exists
 */
int ast_check_realtime(const char *family);

/*! \brief Check if there's any realtime engines loaded */
int ast_realtime_enabled(void);

/*!
 * \brief Duplicate variable list
 * \param var the linked list of variables to clone
 * \return A duplicated list which you'll need to free with
 * ast_variables_destroy or NULL when out of memory.
 *
 * \note Do not depend on this to copy more than just name, value and filename
 * (the arguments to ast_variables_new).
 */
struct ast_variable *ast_variables_dup(struct ast_variable *var);

/*!
 * \brief Reverse a variable list
 * \param var the linked list of variables to reverse
 * \return The head of the reversed variable list
 *
 * \note The variable list var is not preserved in this function and should
 * not be used after reversing it.
 */
struct ast_variable *ast_variables_reverse(struct ast_variable *var);

/*!
 * \brief Free variable list
 * \param var the linked list of variables to free
 *
 * \details
 * This function frees a list of variables.
 */
void ast_variables_destroy(struct ast_variable *var);

/*!
 * \brief Register config engine
 * \retval 1 Always
 */
int ast_config_engine_register(struct ast_config_engine *newconfig);

/*!
 * \brief Deregister config engine
 * \retval 0 Always
 */
int ast_config_engine_deregister(struct ast_config_engine *del);

/*!
 * \brief Determine if a mapping exists for a given family
 *
 * \param family which family you are looking to see if a mapping exists for
 * \retval 1 if it is mapped
 * \retval 0 if it is not
 */
int ast_realtime_is_mapping_defined(const char *family);

/*!
 * \brief Exposed initialization method for core process
 *
 * \details
 * This method is intended for use only with the core initialization and is
 * not designed to be called from any user applications.
 */
int register_config_cli(void);

/*!
 * \brief Exposed re-initialization method for core process
 *
 * \details
 * This method is intended for use only with the core re-initialization and is
 * not designed to be called from any user applications.
 */
int read_config_maps(void);

/*! \brief Create a new base configuration structure */
struct ast_config *ast_config_new(void);

/*!
 * \brief Retrieve the current category name being built.
 *
 * \details
 * API for backend configuration engines while building a configuration set.
 */
struct ast_category *ast_config_get_current_category(const struct ast_config *cfg);

/*!
 * \brief Set the category within the configuration as being current.
 *
 * \details
 * API for backend configuration engines while building a configuration set.
 */
void ast_config_set_current_category(struct ast_config *cfg, const struct ast_category *cat);

/*!
 * \brief Retrieve a configuration variable within the configuration set.
 *
 * \details
 * Retrieves the named variable \p var within category \p cat of configuration
 * set \p cfg.  If not found, attempts to retrieve the named variable \p var
 * from within category \em general.
 *
 * \return Value of \p var, or NULL if not found.
 */
const char *ast_config_option(struct ast_config *cfg, const char *cat, const char *var);

/*! \brief Create a category structure */
struct ast_category *ast_category_new(const char *name, const char *in_file, int lineno);
void ast_category_append(struct ast_config *config, struct ast_category *cat);

/*!
 * \brief Inserts new category
 * 
 * \param config which config to use
 * \param cat newly created category to insert
 * \param match which category to insert above
 *
 * \details
 * This function is used to insert a new category above another category
 * matching the match parameter.
 */
void ast_category_insert(struct ast_config *config, struct ast_category *cat, const char *match);
int ast_category_delete(struct ast_config *cfg, const char *category);

/*!
 * \brief Removes and destroys all variables within a category
 * \retval 0 if the category was found and emptied
 * \retval -1 if the category was not found
 */
int ast_category_empty(struct ast_config *cfg, const char *category);
void ast_category_destroy(struct ast_category *cat);
struct ast_variable *ast_category_detach_variables(struct ast_category *cat);
void ast_category_rename(struct ast_category *cat, const char *name);

#ifdef MALLOC_DEBUG
struct ast_variable *_ast_variable_new(const char *name, const char *value, const char *filename, const char *file, const char *function, int lineno);
#define ast_variable_new(a, b, c) _ast_variable_new(a, b, c, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#else
struct ast_variable *ast_variable_new(const char *name, const char *value, const char *filename);
#endif
struct ast_config_include *ast_include_new(struct ast_config *conf, const char *from_file, const char *included_file, int is_exec, const char *exec_file, int from_lineno, char *real_included_file_name, int real_included_file_name_size);
struct ast_config_include *ast_include_find(struct ast_config *conf, const char *included_file);
void ast_include_rename(struct ast_config *conf, const char *from_file, const char *to_file);
void ast_variable_append(struct ast_category *category, struct ast_variable *variable);
void ast_variable_insert(struct ast_category *category, struct ast_variable *variable, const char *line);
int ast_variable_delete(struct ast_category *category, const char *variable, const char *match, const char *line);

/*!
 * \brief Update variable value within a config
 *
 * \param category Category element within the config
 * \param variable Name of the variable to change
 * \param value New value of the variable
 * \param match If set, previous value of the variable (if NULL or zero-length, no matching will be done)
 * \param object Boolean of whether to make the new variable an object
 *
 * \return 0 on success or -1 on failure.
 */
int ast_variable_update(struct ast_category *category, const char *variable,
                  const char *value, const char *match, unsigned int object);

int ast_config_text_file_save(const char *filename, const struct ast_config *cfg, const char *generator);
int config_text_file_save(const char *filename, const struct ast_config *cfg, const char *generator) __attribute__((deprecated));

struct ast_config *ast_config_internal_load(const char *configfile, struct ast_config *cfg, struct ast_flags flags, const char *suggested_incl_file, const char *who_asked);
/*!
 * \brief
 * Copies the contents of one ast_config into another
 *
 * \note
 * This creates a config on the heap. The caller of this must
 * be prepared to free the memory returned.
 *
 * \param orig the config to copy
 * \return The new config on success, NULL on failure.
 */
struct ast_config *ast_config_copy(const struct ast_config *orig);

/*!
 * \brief
 * Flags that affect the behaviour of config hooks.
 */
enum config_hook_flags {
   butt,
};

/*
 * \brief Callback when configuration is updated
 *
 * \param cfg A copy of the configuration that is being changed.
 *            This MUST be freed by the callback before returning.
 */
typedef int (*config_hook_cb)(struct ast_config *cfg);

/*!
 * \brief
 * Register a config hook for a particular file and module
 *
 * \param name The name of the hook you are registering.
 * \param filename The file whose config you wish to hook into.
 * \param module The module that is reloading the config. This
 *               can be useful if multiple modules may possibly
 *               reload the same file, but you are only interested
 *               when a specific module reloads the file
 * \param flags Flags that affect the way hooks work.
 * \param hook The callback to be called when config is loaded.
 * return 0 Success
 * return -1 Unsuccess, also known as UTTER AND COMPLETE FAILURE
 */
int ast_config_hook_register(const char *name,
      const char *filename,
      const char *module,
      enum config_hook_flags flags,
      config_hook_cb hook);

/*!
 * \brief
 * Unregister a config hook
 *
 * \param name The name of the hook to unregister
 */
void ast_config_hook_unregister(const char *name);

/*!
 * \brief Support code to parse config file arguments
 *
 * \details
 * The function ast_parse_arg() provides a generic interface to parse
 * strings (e.g. numbers, network addresses and so on) in a flexible
 * way, e.g. by doing proper error and bound checks, provide default
 * values, and so on.
 * The function (described later) takes a string as an argument,
 * a set of flags to specify the result format and checks to perform,
 * a pointer to the result, and optionally some additional arguments.
 *
 * \return It returns 0 on success, != 0 otherwise.
 */
enum ast_parse_flags {
   /* low 4 bits of flags are used for the operand type */
   PARSE_TYPE  =  0x000f,
   /* numeric types, with optional default value and bound checks.
    * Additional arguments are passed by value.
    */
   PARSE_INT32 =  0x0001,
   PARSE_UINT32   =  0x0002,
   PARSE_DOUBLE   =  0x0003,
#if 0 /* not supported yet */
   PARSE_INT16 =  0x0004,
   PARSE_UINT16   =  0x0005,
#endif

   /* Returns a struct ast_sockaddr, with optional default value
    * (passed by reference) and port handling (accept, ignore,
    * require, forbid). The format is 'ipaddress[:port]'. IPv6 address
    * literals need square brackets around them if a port is specified.
    */
   PARSE_ADDR  =  0x000e,

   /* Returns a struct sockaddr_in, with optional default value
    * (passed by reference) and port handling (accept, ignore,
    * require, forbid). The format is 'host.name[:port]'
    */
   PARSE_INADDR   =  0x000f,

   /* Other data types can be added as needed */

   /* If PARSE_DEFAULT is set, next argument is a default value
    * which is returned in case of error. The argument is passed
    * by value in case of numeric types, by reference in other cases.
    */
   PARSE_DEFAULT  =  0x0010,  /* assign default on error */

   /* Request a range check, applicable to numbers. Two additional
    * arguments are passed by value, specifying the low-high end of
    * the range (inclusive). An error is returned if the value
    * is outside or inside the range, respectively.
    */
   PARSE_IN_RANGE =       0x0020, /* accept values inside a range */
   PARSE_OUT_RANGE =      0x0040, /* accept values outside a range */
   PARSE_RANGE_DEFAULTS = 0x0080, /* default to range min/max on range error */

   /* Port handling, for ast_sockaddr. accept/ignore/require/forbid
    * port number after the hostname or address.
    */
   PARSE_PORT_MASK = 0x0300, /* 0x000: accept port if present */
   PARSE_PORT_IGNORE =  0x0100, /* 0x100: ignore port if present */
   PARSE_PORT_REQUIRE = 0x0200, /* 0x200: require port number */
   PARSE_PORT_FORBID =  0x0300, /* 0x100: forbid port number */
};

/*!
 * \brief The argument parsing routine.
 *
 * \param arg the string to parse. It is not modified.
 * \param flags combination of ast_parse_flags to specify the
 * return type and additional checks.
 * \param result pointer to the result. NULL is valid here, and can
 * be used to perform only the validity checks.
 * \param ... extra arguments are required according to flags.
 *
 * \retval 0 in case of success, != 0 otherwise.
 * \retval result returns the parsed value in case of success,
 * the default value in case of error, or it is left unchanged
 * in case of error and no default specified. Note that in certain
 * cases (e.g. sockaddr_in, with multi-field return values) some
 * of the fields in result may be changed even if an error occurs.
 *
 * \details
 * Examples of use:
 *     ast_parse_arg("223", PARSE_INT32|PARSE_IN_RANGE, &a, -1000, 1000);
 * returns 0, a = 223
 *     ast_parse_arg("22345", PARSE_INT32|PARSE_IN_RANGE|PARSE_DEFAULT, &a, 9999, 10, 100);
 * returns 1, a = 9999
 *     ast_parse_arg("22345ssf", PARSE_UINT32|PARSE_IN_RANGE, &b, 10, 100);
 * returns 1, b unchanged
 *    ast_parse_arg("12", PARSE_UINT32|PARSE_IN_RANGE|PARSE_RANGE_DEFAULTS, &a, 1, 10);
 * returns 1, a = 10
 *    ast_parse_arg("www.foo.biz:44", PARSE_INADDR, &sa);
 * returns 0, sa contains address and port
 *    ast_parse_arg("www.foo.biz", PARSE_INADDR|PARSE_PORT_REQUIRE, &sa);
 * returns 1 because port is missing, sa contains address
 */
int ast_parse_arg(const char *arg, enum ast_parse_flags flags,
        void *result, ...);

/*
 * Parsing config file options in C is slightly annoying because we cannot use
 * string in a switch() statement, yet we need a similar behaviour, with many
 * branches and a break on a matching one.
 * The following somehow simplifies the job: we create a block using
 * the CV_START and CV_END macros, and then within the block we can run
 * actions such as "if (condition) { body; break; }"
 * Additional macros are present to run simple functions (e.g. ast_copy_string)
 * or to pass arguments to ast_parse_arg()
 *
 * As an example:

   CV_START(v->name, v->value);  // start the block
   CV_STR("foo", x_foo);      // static string
   CV_DSTR("bar", y_bar);     // malloc'ed string
   CV_F("bar", ...);    // call a generic function
   CV_END;           // end the block
 */

/*! \brief the macro to open a block for variable parsing */
#define CV_START(__in_var, __in_val)      \
   do {              \
      const char *__var = __in_var; \
      const char *__val = __in_val;

/*! \brief close a variable parsing block */
#define  CV_END         } while (0)

/*! \brief call a generic function if the name matches. */
#define  CV_F(__pattern, __body) if (!strcasecmp((__var), __pattern)) { __body; break; }

/*!
 * \brief helper macros to assign the value to a BOOL, UINT, static string and
 * dynamic string
 */
#define  CV_BOOL(__x, __dst)  CV_F(__x, (__dst) = ast_true(__val) )
#define CV_UINT(__x, __dst)   CV_F(__x, (__dst) = strtoul(__val, NULL, 0) )
#define CV_STR(__x, __dst) CV_F(__x, ast_copy_string(__dst, __val, sizeof(__dst)))
#define CV_DSTR(__x, __dst)   CV_F(__x, ast_free(__dst); __dst = ast_strdup(__val))
#define CV_STRFIELD(__x, __obj, __field) CV_F(__x, ast_string_field_set(__obj, __field, __val))

/*! \brief Check if require type is an integer type */
AST_INLINE_API(
int ast_rq_is_int(require_type type),
{
   switch (type) {
   case RQ_INTEGER1:
   case RQ_UINTEGER1:
   case RQ_INTEGER2:
   case RQ_UINTEGER2:
   case RQ_INTEGER3:
   case RQ_UINTEGER3:
   case RQ_INTEGER4:
   case RQ_UINTEGER4:
   case RQ_INTEGER8:
   case RQ_UINTEGER8:
      return 1;
   default:
      return 0;
   }
}
)

/*!
 * \brief Remove standard encoding from realtime values, which ensures
 * that a semicolon embedded within a single value is not treated upon
 * retrieval as multiple values.
 * \param chunk Data to be decoded
 * \return The decoded data, in the original buffer
 * \since 1.8
 * \warn This function modifies the original buffer
 */
char *ast_realtime_decode_chunk(char *chunk);

/*!
 * \brief Encodes a chunk of data for realtime
 * \param dest Destination buffer
 * \param maxlen Length passed through to ast_str_* functions
 * \param chunk Source data to be encoded
 * \return Buffer within dest
 * \since 1.8
 */
char *ast_realtime_encode_chunk(struct ast_str **dest, ssize_t maxlen, const char *chunk);

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif /* _ASTERISK_CONFIG_H */