container.h

net_snmp应用程序示例

#ifndef NETSNMP_CONTAINER_H
#define NETSNMP_CONTAINER_H

/*
 * $Id: container.h,v 1.32 2005/12/04 18:43:04 rstory Exp $
 *
 * WARNING: This is a recently created file, and all of it's contents are
 *          subject to change at any time.
 *
 * A basic container template. A generic way for code to store and
 * retrieve data. Allows for interchangable storage algorithms.
 */
#ifndef NET_SNMP_CONFIG_H
#error "Please include <net-snmp/net-snmp-config.h> before this file"
#endif

#include <net-snmp/types.h>
#include <net-snmp/library/factory.h>
#include <net-snmp/library/snmp_logging.h>

#ifdef  __cplusplus
extern "C" {
#endif

    /*************************************************************************
     *
     * function pointer definitions
     *
     *************************************************************************/
    struct netsnmp_iterator_s; /** forward declare */
    struct netsnmp_container_s; /** forward declare */

    /*
     * function returning an int for an operation on a container
     */
    typedef int (netsnmp_container_option)(struct netsnmp_container_s *,
                                           int set, u_int flags);

    /*
     * function returning an int for an operation on a container
     */
    typedef int (netsnmp_container_rc)(struct netsnmp_container_s *);

    /*
     * function returning an iterator for a container
     */
    typedef struct netsnmp_iterator_s * (netsnmp_container_it)
        (struct netsnmp_container_s *);

    /*
     * function returning a size_t for an operation on a container
     */
    typedef size_t (netsnmp_container_size)(struct netsnmp_container_s *);

    /*
     * function returning an int for an operation on an object and
     * a container
     */
    typedef int (netsnmp_container_op)(struct netsnmp_container_s *,
                                       const void *data);

    /*
     * function returning an oject for an operation on an object and a
     * container
     */
    typedef void * (netsnmp_container_rtn)(struct netsnmp_container_s *,
                                           const void *data);

    /*
     * function with no return which acts on an object
     */
    typedef void (netsnmp_container_obj_func)(void *data, void *context);

    /*
     * function with no return which calls a function on an object
     */
    typedef void (netsnmp_container_func)(struct netsnmp_container_s *,
                                          netsnmp_container_obj_func *,
                                          void *context);

    /*
     * function returning an array of objects for an operation on an
     * ojbect and a container
     */
    typedef netsnmp_void_array * (netsnmp_container_set)
        (struct netsnmp_container_s *, void *data);

    /*
     * function returning an int for a comparison between two objects
     */
    typedef int (netsnmp_container_compare)(const void *lhs,
                                            const void *rhs);

    /*************************************************************************
     *
     * Basic container
     *
     *************************************************************************/
    typedef struct netsnmp_container_s {
       
       /*
        * pointer for container implementation
        */
       void *         container_data;

       /*
        * returns the number of items in a container
        */
       netsnmp_container_size  *get_size;
       
       /*
        * initialize a container
        */
       netsnmp_container_rc    *init;

       /*
        * release memory used by a container.
        *
        * Note: if your data structures contained allocated
        * memory, you are responsible for releasing that
        * memory before calling this function!
        */
       netsnmp_container_rc    *cfree;

       /*
        * add an entry to the container
        */
       netsnmp_container_op    *insert;

       /*
        * remove an entry from the container
        */
       netsnmp_container_op    *remove;

       /*
        * release memory for an entry from the container
        */
       netsnmp_container_op    *release;

       /*
        * Note: do not change the key!  If you need to
        * change a key, remove the entry, change the key,
        * and the re-add the entry.
        */

       /*
        * find the entry in the container with the same key
        *
        */
       netsnmp_container_rtn   *find;

       /*
        * find the entry in the container with the next highest key
        *
        * If the key is NULL, return the first item in the container.
        */
       netsnmp_container_rtn   *find_next;

       /*
        * find all entries in the container which match the partial key
        * returns allocated memory (netsnmp_void_array). User is responsible
        * for releasing this memory (free(array->array), free(array)).
        * DO NOT FREE ELEMENTS OF THE ARRAY, because they are the same pointers
        * stored in the container.
        */
       netsnmp_container_set            *get_subset;

       /*
        * function to return an iterator for the container
        */
       netsnmp_container_it           *get_iterator;

       /*
        * function to call another function for each object in the container
        */
       netsnmp_container_func         *for_each;

       /*
        * specialized version of for_each used to optimize cleanup.
        * clear the container, optionally calling a function for each item.
        */
       netsnmp_container_func         *clear;

       /*
        * OPTIONAL function to filter inserts to the container
        *  (intended for a secondary container, which only wants
        *   a sub-set of the objects in the primary/parent container)
        * Returns:
        *   1 : filter matched (don't insert)
        *   0 : no match (insert)
        */
       netsnmp_container_op    *insert_filter;

       /*
        * function to compare two object stored in the container.
        *
        * Returns:
        *
        *   -1  LHS < RHS
        *    0  LHS = RHS
        *    1  LHS > RHS
        */
       netsnmp_container_compare        *compare;

       /*
        * same as compare, but RHS will be a partial key
        */
       netsnmp_container_compare        *ncompare;

       /*
        * function to set container options
        */
       netsnmp_container_option         *options;

       /*
        * unique name for finding a particular container in a list
        */
       char *container_name;

       /*
        * sort count, for iterators to track (insert/delete
        * bumps coutner, invalidates iterator
        */
       u_long                          sync;

       /*
        * containers can contain other containers (additional indexes)
        */
       struct netsnmp_container_s *next, *prev;

    } netsnmp_container;

    /*
     * initialize/free a container of container factories. used by
     * netsnmp_container_find* functions.
     */
    void netsnmp_container_init_list(void);
    void netsnmp_container_free_list(void);

    /*
     * register a new container factory
     */
    int netsnmp_container_register_with_compare(const char* name,
                                                netsnmp_factory *f,
                                                netsnmp_container_compare *c);
    int netsnmp_container_register(const char* name, netsnmp_factory *f);

    /*
     * search for and create a container from a list of types or a
     * specific type.
     */
    netsnmp_container * netsnmp_container_find(const char *type_list);
    netsnmp_container * netsnmp_container_get(const char *type);

    /*
     * utility routines
     */
    void netsnmp_container_add_index(netsnmp_container *primary,
                                     netsnmp_container *new_index);


    netsnmp_factory *netsnmp_container_get_factory(const char *type);

    /*
     * common comparison routines
     */
    /** first data element is a 'netsnmp_index' */
    int netsnmp_compare_netsnmp_index(const void *lhs, const void *rhs);
    int netsnmp_ncompare_netsnmp_index(const void *lhs, const void *rhs);