rte_kvargs.h

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2013 Intel Corporation.
 * Copyright(c) 2014 6WIND S.A.
 */

#ifndef _RTE_KVARGS_H_
#define _RTE_KVARGS_H_

/**
 * @file
 * RTE Argument parsing
 *
 * This module can be used to parse arguments whose format is
 * key1=value1,key2=value2,key3=value3,...
 *
 * The same key can appear several times with the same or a different
 * value. Indeed, the arguments are stored as a list of key/values
 * associations and not as a dictionary.
 *
 * This file provides some helpers that are especially used by virtual
 * ethernet devices at initialization for arguments parsing.
 */

#ifdef __cplusplus
extern "C" {
#endif

/** Maximum number of key/value associations */
#define RTE_KVARGS_MAX 32

/** separator character used between each pair */
#define RTE_KVARGS_PAIRS_DELIM	","

/** separator character used between key and value */
#define RTE_KVARGS_KV_DELIM	"="

/**
 * Callback prototype used by rte_kvargs_process().
 *
 * @param key
 *   The key to consider, it will not be NULL.
 * @param value
 *   The value corresponding to the key, it may be NULL (e.g. only with key)
 * @param opaque
 *   An opaque pointer coming from the caller.
 * @return
 *   - >=0 handle key success.
 *   - <0 on error.
 */
typedef int (*arg_handler_t)(const char *key, const char *value, void *opaque);

/** A key/value association */
struct rte_kvargs_pair {
	char *key;      /**< the name (key) of the association  */
	char *value;    /**< the value associated to that key */
};

/** Store a list of key/value associations */
struct rte_kvargs {
	char *str;      /**< copy of the argument string */
	unsigned count; /**< number of entries in the list */
	struct rte_kvargs_pair pairs[RTE_KVARGS_MAX]; /**< list of key/values */
};

/**
 * Allocate a rte_kvargs and store key/value associations from a string
 *
 * The function allocates and fills a rte_kvargs structure from a given
 * string whose format is key1=value1,key2=value2,...
 *
 * The structure can be freed with rte_kvargs_free().
 *
 * @param args
 *   The input string containing the key/value associations
 * @param valid_keys
 *   A list of valid keys (table of const char *, the last must be NULL).
 *   This argument is ignored if NULL
 *
 * @return
 *   - A pointer to an allocated rte_kvargs structure on success
 *   - NULL on error
 */
struct rte_kvargs *rte_kvargs_parse(const char *args,
		const char *const valid_keys[]);

/**
 * Allocate a rte_kvargs and store key/value associations from a string.
 * This version will consider any byte from valid_ends as a possible
 * terminating character, and will not parse beyond any of their occurrence.
 *
 * The function allocates and fills an rte_kvargs structure from a given
 * string whose format is key1=value1,key2=value2,...
 *
 * The structure can be freed with rte_kvargs_free().
 *
 * @param args
 *   The input string containing the key/value associations
 *
 * @param valid_keys
 *   A list of valid keys (table of const char *, the last must be NULL).
 *   This argument is ignored if NULL
 *
 * @param valid_ends
 *   Acceptable terminating characters.
 *   If NULL, the behavior is the same as ``rte_kvargs_parse``.
 *
 * @return
 *   - A pointer to an allocated rte_kvargs structure on success
 *   - NULL on error
 */
struct rte_kvargs *rte_kvargs_parse_delim(const char *args,
		const char *const valid_keys[],
		const char *valid_ends);

/**
 * Free a rte_kvargs structure
 *
 * Free a rte_kvargs structure previously allocated with
 * rte_kvargs_parse().
 *
 * @param kvlist
 *   The rte_kvargs structure. No error if NULL.
 */
void rte_kvargs_free(struct rte_kvargs *kvlist);

/**
 * Get the value associated with a given key.
 *
 * If multiple keys match, the value of the first one is returned.
 *
 * The memory returned is allocated as part of the rte_kvargs structure,
 * it must never be modified.
 *
 * @param kvlist
 *   A list of rte_kvargs pair of 'key=value'.
 * @param key
 *   The matching key.
 *
 * @return
 *   NULL if no key matches the input,
 *   a value associated with a matching key otherwise.
 */
const char *rte_kvargs_get(const struct rte_kvargs *kvlist, const char *key);

/**
 * Get the value associated with a given key and value.
 *
 * Find the first entry in the kvlist whose key and value match the
 * ones passed as argument.
 *
 * The memory returned is allocated as part of the rte_kvargs structure,
 * it must never be modified.
 *
 * @param kvlist
 *   A list of rte_kvargs pair of 'key=value'.
 * @param key
 *   The matching key. If NULL, any key will match.
 * @param value
 *   The matching value. If NULL, any value will match.
 *
 * @return
 *   NULL if no key matches the input,
 *   a value associated with a matching key otherwise.
 */
const char *rte_kvargs_get_with_value(const struct rte_kvargs *kvlist,
				      const char *key, const char *value);

/**
 * Call a handler function for each key=value matching the key
 *
 * For each key=value association that matches the given key, calls the
 * handler function with the for a given arg_name passing the value on the
 * dictionary for that key and a given extra argument.
 *
 * @note Compared to @see rte_kvargs_process_opt, this API will return -1
 * when handle only-key case (that is the matched key's value is NULL).
 *
 * @param kvlist
 *   The rte_kvargs structure.
 * @param key_match
 *   The key on which the handler should be called, or NULL to process handler
 *   on all associations
 * @param handler
 *   The function to call for each matching key
 * @param opaque_arg
 *   A pointer passed unchanged to the handler
 *
 * @return
 *   - 0 on success
 *   - Negative on error
 */
int rte_kvargs_process(const struct rte_kvargs *kvlist,
	const char *key_match, arg_handler_t handler, void *opaque_arg);

/**
 * Call a handler function for each key=value or only-key matching the key
 *
 * For each key=value or only-key association that matches the given key, calls
 * the handler function with the for a given arg_name passing the value on the
 * dictionary for that key and a given extra argument.
 *
 * @param kvlist
 *   The rte_kvargs structure.
 * @param key_match
 *   The key on which the handler should be called, or NULL to process handler
 *   on all associations
 * @param handler
 *   The function to call for each matching key
 * @param opaque_arg
 *   A pointer passed unchanged to the handler
 *
 * @return
 *   - 0 on success
 *   - Negative on error
 */
int rte_kvargs_process_opt(const struct rte_kvargs *kvlist,
	const char *key_match, arg_handler_t handler, void *opaque_arg);

/**
 * Count the number of associations matching the given key
 *
 * @param kvlist
 *   The rte_kvargs structure
 * @param key_match
 *   The key that should match, or NULL to count all associations
 *
 * @return
 *   The number of entries
 */
unsigned rte_kvargs_count(const struct rte_kvargs *kvlist,
	const char *key_match);

#ifdef __cplusplus
}
#endif

#endif