Thanks to snuffy for this doxygen update to hashtab.h; closes issue #11223
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@89198 65c4cc65-6c06-0410-ace0-fbb531ad65f3
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Steve Murphy
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@ -19,9 +19,10 @@
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#define _ASTERISK_HASHTAB_H_
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#define __USE_UNIX98 1 /* to get the MUTEX_RECURSIVE stuff */
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/* generic (perhaps overly so) hashtable implementation */
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/* notes:
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/*! \file
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* \brief Generic (perhaps overly so) hashtable implementation
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*/
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/*! \note
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A hash table is a structure that allows for an exact-match search
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in O(1) (or close to that) time.
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@ -67,35 +68,36 @@ This implementation is pretty generic, because:
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struct ast_hashtab_bucket
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{
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const void *object; /* whatever it is we are storing in this table */
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struct ast_hashtab_bucket *next; /* a DLL of buckets in hash collision */
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struct ast_hashtab_bucket *prev; /* a DLL of buckets in hash collision */
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struct ast_hashtab_bucket *tnext; /* a DLL of all the hash buckets for traversal */
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struct ast_hashtab_bucket *tprev; /* a DLL of all the hash buckets for traversal */
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const void *object; /*!< whatever it is we are storing in this table */
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struct ast_hashtab_bucket *next; /*!< a DLL of buckets in hash collision */
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struct ast_hashtab_bucket *prev; /*!< a DLL of buckets in hash collision */
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struct ast_hashtab_bucket *tnext; /*!< a DLL of all the hash buckets for traversal */
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struct ast_hashtab_bucket *tprev; /*!< a DLL of all the hash buckets for traversal */
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};
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struct ast_hashtab
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{
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struct ast_hashtab_bucket **array;
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struct ast_hashtab_bucket *tlist; /* the head of a DLList of all the hashbuckets in the table (for traversal). */
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struct ast_hashtab_bucket *tlist; /*!< the head of a DLList of all the hashbuckets in the table (for traversal). */
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int (*compare) (const void *a, const void *b); /* a ptr to func that returns int, and take two void* ptrs, compares them,
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int (*compare) (const void *a, const void *b); /*!< a ptr to func that returns int, and take two void* ptrs, compares them,
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rets -1 if a < b; rets 0 if a==b; rets 1 if a>b */
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int (*newsize) (struct ast_hashtab *tab); /* a ptr to func that returns int, a new size for hash tab, based on curr_size */
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int (*resize) (struct ast_hashtab *tab); /* a function to decide whether this hashtable should be resized now */
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unsigned int (*hash) (const void *obj); /* a hash func ptr for this table. Given a raw ptr to an obj,
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int (*newsize) (struct ast_hashtab *tab); /*!< a ptr to func that returns int, a new size for hash tab, based on curr_size */
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int (*resize) (struct ast_hashtab *tab); /*!< a function to decide whether this hashtable should be resized now */
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unsigned int (*hash) (const void *obj); /*!< a hash func ptr for this table. Given a raw ptr to an obj,
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it calcs a hash.*/
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int hash_tab_size; /* the size of the bucket array */
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int hash_tab_elements; /* the number of objects currently stored in the table */
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int largest_bucket_size; /* a stat on the health of the table */
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int resize_count; /* a count of the number of times this table has been
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int hash_tab_size; /*!< the size of the bucket array */
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int hash_tab_elements; /*!< the number of objects currently stored in the table */
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int largest_bucket_size; /*!< a stat on the health of the table */
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int resize_count; /*!< a count of the number of times this table has been
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resized */
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int do_locking; /* if 1, use locks to guarantee safety of insertions/deletions */
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int do_locking; /*!< if 1 use locks to guarantee safety of insertions/deletions */
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/* this spot reserved for the proper lock storage */
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ast_rwlock_t lock; /* is this as good as it sounds? */
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};
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struct ast_hashtab_iter /* an iterator for traversing the buckets */
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/*! \brief an iterator for traversing the buckets */
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struct ast_hashtab_iter
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{
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struct ast_hashtab *tab;
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struct ast_hashtab_bucket *next;
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@ -104,42 +106,67 @@ struct ast_hashtab_iter /* an iterator for traversing the buckets *
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/* some standard, default routines for general use */
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int isPrime(int num); /* this one is handy for sizing the hash table, tells if num is prime or not */
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/*! \brief For sizing the hash table, tells if num is prime or not */
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int isPrime(int num);
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int ast_hashtab_compare_strings(const void *a, const void *b); /* assumes a and b are char * and returns 0 if they match */
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/*!
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* \brief assumes a and b are char *
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* \return 0 if they match
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*/
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int ast_hashtab_compare_strings(const void *a, const void *b);
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/*!
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* \brief assumes a & b are strings
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* \return 0 if they match (strcasecmp)
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*/
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int ast_hashtab_compare_strings_nocase(const void *a, const void *b);
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int ast_hashtab_compare_strings_nocase(const void *a, const void *b); /* assumes a & b are strings, returns 0 if they match (strcasecmp) */
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/*!
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* \brief assumes a & b are int *
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* \retval 0 if match
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* \retval 1 a > b
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* \retval -1 a < b
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*/
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int ast_hashtab_compare_ints(const void *a, const void *b);
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/*!
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* \brief assumes a & b are short *
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* \retval 0 if match
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* \retval 1 a > b
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* \retval -1 a < b
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*/
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int ast_hashtab_compare_shorts(const void *a, const void *b);
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int ast_hashtab_compare_ints(const void *a, const void *b); /* assumes a & b are int *, returns a != b */
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/*!
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* \brief determine if resize should occur
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* \returns 1 if the table is 75% full or more
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*/
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int ast_hashtab_resize_java(struct ast_hashtab *tab);
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/*! \brief no resizing; always return 0 */
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int ast_hashtab_resize_tight(struct ast_hashtab *tab);
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int ast_hashtab_compare_shorts(const void *a, const void *b); /* assumes a & b are short *, returns a != b */
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/*! \brief no resizing; always return 0 */
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int ast_hashtab_resize_none(struct ast_hashtab *tab);
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/*! \brief Create a prime number roughly 2x the current table size */
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int ast_hashtab_newsize_java(struct ast_hashtab *tab);
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int ast_hashtab_resize_java(struct ast_hashtab *tab); /* returns 1 if the table is 75% full or more */
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/* not yet specified, probably will return 1.5x the current table size */
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int ast_hashtab_newsize_tight(struct ast_hashtab *tab);
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/*! \brief always return current size -- no resizing */
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int ast_hashtab_newsize_none(struct ast_hashtab *tab);
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int ast_hashtab_resize_tight(struct ast_hashtab *tab); /* not yet specified; probably will return 1 if table is 100% full */
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/*!
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* \brief Hashes a string to a number
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* \param obj
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* \note A modulus is applied so it in the range 0 to mod-1
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*/
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unsigned int ast_hashtab_hash_string(const void *obj);
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int ast_hashtab_resize_none(struct ast_hashtab *tab); /* no resizing; always return 0 */
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int ast_hashtab_newsize_java(struct ast_hashtab *tab); /* returns a prime number roughly 2x the current table size */
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int ast_hashtab_newsize_tight(struct ast_hashtab *tab); /* not yet specified, probably will return 1.5x the current table size */
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int ast_hashtab_newsize_none(struct ast_hashtab *tab); /* always return current size -- no resizing */
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unsigned int ast_hashtab_hash_string(const void *obj); /* hashes a string to a number, mod is applied so it in the range 0 to mod-1 */
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unsigned int ast_hashtab_hash_string_nocase(const void *obj); /* upcases each char before using them for a hash */
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/*! \brief Upperases each char before using them for a hash */
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unsigned int ast_hashtab_hash_string_nocase(const void *obj);
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unsigned int ast_hashtab_hash_string_sax(const void *obj); /* from Josh */
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@ -151,94 +178,127 @@ unsigned int ast_hashtab_hash_int(const int num); /* right now, both these func
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unsigned int ast_hashtab_hash_short(const short num);
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/*!
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* \brief Create the hashtable list
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* \param initial_buckets starting number of buckets
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* \param compare a func ptr to compare two elements in the hash -- cannot be null
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* \param resize a func ptr to decide if the table needs to be resized, a NULL ptr here will cause a default to be used
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* \param newsize a func ptr that returns a new size of the array. A NULL will cause a default to be used
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* \param hash a func ptr to do the hashing
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* \param do_locking use locks to guarantee safety of iterators/insertion/deletion -- real simpleminded right now
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*/
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struct ast_hashtab * ast_hashtab_create(int initial_buckets,
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int (*compare)(const void *a, const void *b), /* a func to compare two elements in the hash -- cannot be null */
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int (*resize)(struct ast_hashtab *), /* a func to decide if the table needs to be resized,
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a NULL ptr here will cause a default to be used */
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int (*newsize)(struct ast_hashtab *tab), /* a ptr to func that returns a new size of the array.
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A NULL will cause a default to be used */
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unsigned int (*hash)(const void *obj), /* a func to do the hashing */
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int do_locking ); /* use locks to guarantee safety of iterators/insertion/deletion */
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int (*compare)(const void *a, const void *b),
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int (*resize)(struct ast_hashtab *),
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int (*newsize)(struct ast_hashtab *tab),
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unsigned int (*hash)(const void *obj),
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int do_locking );
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/* this func will free the hash table and all its memory. It
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doesn't touch the objects stored in it */
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/*!
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* \brief This func will free the hash table and all its memory.
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* \note It doesn't touch the objects stored in it
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* \param tab
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* \param objdestroyfunc
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*/
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void ast_hashtab_destroy( struct ast_hashtab *tab, void (*objdestroyfunc)(void *obj));
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/* normally, you'd insert "safely" by checking to see if the element is
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already there; in this case, you must already have checked. If an element
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is already in the hashtable, that matches this one, most likely this one
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will be found first. */
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/* will force a resize if the resize func returns 1 */
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/* returns 1 on success, 0 if there's a problem */
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/*!
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* \brief Insert without checking
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* \param tab
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* \param obj
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*
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* Normally, you'd insert "safely" by checking to see if the element is
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* already there; in this case, you must already have checked. If an element
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* is already in the hashtable, that matches this one, most likely this one
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* will be found first.
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* \note will force a resize if the resize func returns 1
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* \retval 1 on success
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* \retval 0 if there's a problem
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*/
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int ast_hashtab_insert_immediate(struct ast_hashtab *tab, const void *obj);
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/* same as the above, but h is the hash index; won't hash to find the index */
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/*!
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* \brief Insert without checking, hashing or locking
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* \param tab
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* \param obj
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* \param h hashed index value
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*
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* \note Will force a resize if the resize func returns 1
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* \retval 1 on success
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* \retval 0 if there's a problem
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*/
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int ast_hashtab_insert_immediate_bucket(struct ast_hashtab *tab, const void *obj, unsigned int h);
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/* check to see if the element is already there; insert only if
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it is not there.*/
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/* will force a resize if the resize func returns 1 */
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/* returns 1 on success, 0 if there's a problem, or it's already there. */
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/*!
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* \brief Check and insert new object only if it is not there.
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* \note Will force a resize if the resize func returns 1
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* \retval 1 on success
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* \retval 0 if there's a problem, or it's already there.
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*/
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int ast_hashtab_insert_safe(struct ast_hashtab *tab, const void *obj);
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/* lookup this object in the hash table. return a ptr if found, or NULL if not */
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/*!
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* \brief Lookup this object in the hash table.
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* \param tab
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* \param obj
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* \retval a ptr if found
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* \retval NULL if not found
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*/
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void * ast_hashtab_lookup(struct ast_hashtab *tab, const void *obj);
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/* if you know the hash val for the object, then use this and avoid the recalc
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of the hash (the modulus (table_size) is not applied) */
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/*!
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* \brief Use this if have the hash val for the object
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* \note This and avoid the recalc of the hash (the modulus (table_size) is not applied)
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*/
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void * ast_hashtab_lookup_with_hash(struct ast_hashtab *tab, const void *obj, unsigned int hashval);
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/* same as the above lookup, but sets h to the key hash value if the lookup fails -- this has the modulus
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applied, and will not be useful for long term storage if the table is resizable */
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/*!
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* \brief Similar to ast_hashtab_lookup but sets h to the key hash value if the lookup fails.
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* \note This has the modulus applied, and will not be useful for long term storage if the table is resizable.
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*/
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void * ast_hashtab_lookup_bucket(struct ast_hashtab *tab, const void *obj, unsigned int *h);
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/* returns key stats for the table */
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/*! \brief Returns key stats for the table */
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void ast_hashtab_get_stats( struct ast_hashtab *tab, int *biggest_bucket_size, int *resize_count, int *num_objects, int *num_buckets);
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/* this function returns the number of elements stored in the hashtab */
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int ast_hashtab_size( struct ast_hashtab *tab);
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/*! \brief Returns the number of elements stored in the hashtab */
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int ast_hashtab_size( struct ast_hashtab *tab);
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/* this function returns the size of the bucket array in the hashtab */
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int ast_hashtab_capacity( struct ast_hashtab *tab);
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/*! \brief Returns the size of the bucket array in the hashtab */
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int ast_hashtab_capacity( struct ast_hashtab *tab);
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/* this function will return a copy of the table */
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/*! \brief Return a copy of the hash table */
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struct ast_hashtab *ast_hashtab_dup(struct ast_hashtab *tab, void *(*obj_dup_func)(const void *obj));
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/* returns an iterator */
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/*! \brief Gives an iterator to hastable */
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struct ast_hashtab_iter *ast_hashtab_start_traversal(struct ast_hashtab *tab);
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/* end the traversal, free the iterator, unlock if necc. */
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/*! \brief end the traversal, free the iterator, unlock if necc. */
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void ast_hashtab_end_traversal(struct ast_hashtab_iter *it);
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/* returns the next object in the list, advances iter one step, returns null on end of traversal */
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/*! \brief Gets the next object in the list, advances iter one step returns null on end of traversal */
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void *ast_hashtab_next(struct ast_hashtab_iter *it);
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/* looks up the object; removes the corresponding bucket */
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/*! \brief Looks up the object, removes the corresponding bucket */
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void *ast_hashtab_remove_object_via_lookup(struct ast_hashtab *tab, void *obj);
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/* looks up the object by hash and then comparing pts in bucket list instead of
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calling the compare routine; removes the bucket */
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/*! \brief Hash the object and then compare ptrs in bucket list instead of
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calling the compare routine, will remove the bucket */
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void *ast_hashtab_remove_this_object(struct ast_hashtab *tab, void *obj);
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/* ------------------ */
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/* for lock-enabled traversals with ability to remove an object during the traversal*/
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/* ------------------ */
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/* returns an iterator */
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/*! \brief Gives an iterator to hastable */
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struct ast_hashtab_iter *ast_hashtab_start_write_traversal(struct ast_hashtab *tab);
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/* looks up the object; removes the corresponding bucket */
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/*! \brief Looks up the object, removes the corresponding bucket */
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void *ast_hashtab_remove_object_via_lookup_nolock(struct ast_hashtab *tab, void *obj);
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/* looks up the object by hash and then comparing pts in bucket list instead of
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calling the compare routine; removes the bucket */
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/*! \brief Hash the object and then compare ptrs in bucket list instead of
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calling the compare routine, will remove the bucket */
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void *ast_hashtab_remove_this_object_nolock(struct ast_hashtab *tab, void *obj);
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/* ------------------ */
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@ -247,11 +307,16 @@ void *ast_hashtab_remove_this_object_nolock(struct ast_hashtab *tab, void *obj);
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/* user-controlled hashtab locking. Create a hashtab without locking, then call the
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following locking routines yourself to lock the table between threads. */
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void ast_hashtab_initlock(struct ast_hashtab *tab); /* call this after you create the table to init the lock */
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void ast_hashtab_wrlock(struct ast_hashtab *tab); /* request a write-lock on the table. */
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void ast_hashtab_rdlock(struct ast_hashtab *tab); /* request a read-lock on the table-- don't change anything! */
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void ast_hashtab_unlock(struct ast_hashtab *tab); /* release a read- or write- lock. */
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void ast_hashtab_destroylock(struct ast_hashtab *tab); /* call this before you destroy the table. */
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/*! \brief Call this after you create the table to init the lock */
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void ast_hashtab_initlock(struct ast_hashtab *tab);
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/*! \brief Request a write-lock on the table. */
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void ast_hashtab_wrlock(struct ast_hashtab *tab);
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/*! \brief Request a read-lock on the table -- don't change anything! */
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void ast_hashtab_rdlock(struct ast_hashtab *tab);
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/*! \brief release a read- or write- lock. */
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void ast_hashtab_unlock(struct ast_hashtab *tab);
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/*! \brief Call this before you destroy the table. */
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void ast_hashtab_destroylock(struct ast_hashtab *tab);
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#endif
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