1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2
  3/*
  4 * Generic non-thread safe hash map implementation.
  5 *
  6 * Copyright (c) 2019 Facebook
  7 */
  8#ifndef __LIBBPF_HASHMAP_H
  9#define __LIBBPF_HASHMAP_H
 10
 11#include <stdbool.h>
 12#include <stddef.h>
 13#include <limits.h>
 14
 15static inline size_t hash_bits(size_t h, int bits)
 16{
 17	/* shuffle bits and return requested number of upper bits */
 18	if (bits == 0)
 19		return 0;
 20
 21#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
 22	/* LP64 case */
 23	return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
 24#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
 25	return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
 26#else
 27#	error "Unsupported size_t size"
 28#endif
 29}
 30
 31/* generic C-string hashing function */
 32static inline size_t str_hash(const char *s)
 33{
 34	size_t h = 0;
 35
 36	while (*s) {
 37		h = h * 31 + *s;
 38		s++;
 39	}
 40	return h;
 41}
 42
 43typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
 44typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
 45
 46/*
 47 * Hashmap interface is polymorphic, keys and values could be either
 48 * long-sized integers or pointers, this is achieved as follows:
 49 * - interface functions that operate on keys and values are hidden
 50 *   behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;
 51 * - these auxiliary macros cast the key and value parameters as
 52 *   long or long *, so the user does not have to specify the casts explicitly;
 53 * - for pointer parameters (e.g. old_key) the size of the pointed
 54 *   type is verified by hashmap_cast_ptr using _Static_assert;
 55 * - when iterating using hashmap__for_each_* forms
 56 *   hasmap_entry->key should be used for integer keys and
 57 *   hasmap_entry->pkey should be used for pointer keys,
 58 *   same goes for values.
 59 */
 60struct hashmap_entry {
 61	union {
 62		long key;
 63		const void *pkey;
 64	};
 65	union {
 66		long value;
 67		void *pvalue;
 68	};
 69	struct hashmap_entry *next;
 70};
 71
 72struct hashmap {
 73	hashmap_hash_fn hash_fn;
 74	hashmap_equal_fn equal_fn;
 75	void *ctx;
 76
 77	struct hashmap_entry **buckets;
 78	size_t cap;
 79	size_t cap_bits;
 80	size_t sz;
 81};
 82
 83void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
 84		   hashmap_equal_fn equal_fn, void *ctx);
 85struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
 86			     hashmap_equal_fn equal_fn,
 87			     void *ctx);
 88void hashmap__clear(struct hashmap *map);
 89void hashmap__free(struct hashmap *map);
 90
 91size_t hashmap__size(const struct hashmap *map);
 92size_t hashmap__capacity(const struct hashmap *map);
 93
 94/*
 95 * Hashmap insertion strategy:
 96 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
 97 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
 98 *   update value;
 99 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
100 *   nothing and return -ENOENT;
101 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
102 *   This turns hashmap into a multimap by allowing multiple values to be
103 *   associated with the same key. Most useful read API for such hashmap is
104 *   hashmap__for_each_key_entry() iteration. If hashmap__find() is still
105 *   used, it will return last inserted key/value entry (first in a bucket
106 *   chain).
107 */
108enum hashmap_insert_strategy {
109	HASHMAP_ADD,
110	HASHMAP_SET,
111	HASHMAP_UPDATE,
112	HASHMAP_APPEND,
113};
114
115#define hashmap_cast_ptr(p) ({								\
116	_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) ||			\
117				sizeof(*(p)) == sizeof(long),				\
118		       #p " pointee should be a long-sized integer or a pointer");	\
119	(long *)(p);									\
120})
121
122/*
123 * hashmap__insert() adds key/value entry w/ various semantics, depending on
124 * provided strategy value. If a given key/value pair replaced already
125 * existing key/value pair, both old key and old value will be returned
126 * through old_key and old_value to allow calling code do proper memory
127 * management.
128 */
129int hashmap_insert(struct hashmap *map, long key, long value,
130		   enum hashmap_insert_strategy strategy,
131		   long *old_key, long *old_value);
132
133#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
134	hashmap_insert((map), (long)(key), (long)(value), (strategy),  \
135		       hashmap_cast_ptr(old_key),		       \
136		       hashmap_cast_ptr(old_value))
137
138#define hashmap__add(map, key, value) \
139	hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
140
141#define hashmap__set(map, key, value, old_key, old_value) \
142	hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
143
144#define hashmap__update(map, key, value, old_key, old_value) \
145	hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
146
147#define hashmap__append(map, key, value) \
148	hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
149
150bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
151
152#define hashmap__delete(map, key, old_key, old_value)		       \
153	hashmap_delete((map), (long)(key),			       \
154		       hashmap_cast_ptr(old_key),		       \
155		       hashmap_cast_ptr(old_value))
156
157bool hashmap_find(const struct hashmap *map, long key, long *value);
158
159#define hashmap__find(map, key, value) \
160	hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
161
162/*
163 * hashmap__for_each_entry - iterate over all entries in hashmap
164 * @map: hashmap to iterate
165 * @cur: struct hashmap_entry * used as a loop cursor
166 * @bkt: integer used as a bucket loop cursor
167 */
168#define hashmap__for_each_entry(map, cur, bkt)				    \
169	for (bkt = 0; bkt < map->cap; bkt++)				    \
170		for (cur = map->buckets[bkt]; cur; cur = cur->next)
171
172/*
173 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
174 * against removals
175 * @map: hashmap to iterate
176 * @cur: struct hashmap_entry * used as a loop cursor
177 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
178 * @bkt: integer used as a bucket loop cursor
179 */
180#define hashmap__for_each_entry_safe(map, cur, tmp, bkt)		    \
181	for (bkt = 0; bkt < map->cap; bkt++)				    \
182		for (cur = map->buckets[bkt];				    \
183		     cur && ({tmp = cur->next; true; });		    \
184		     cur = tmp)
185
186/*
187 * hashmap__for_each_key_entry - iterate over entries associated with given key
188 * @map: hashmap to iterate
189 * @cur: struct hashmap_entry * used as a loop cursor
190 * @key: key to iterate entries for
191 */
192#define hashmap__for_each_key_entry(map, cur, _key)			    \
193	for (cur = map->buckets						    \
194		     ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
195		     : NULL;						    \
196	     cur;							    \
197	     cur = cur->next)						    \
198		if (map->equal_fn(cur->key, (_key), map->ctx))
199
200#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key)		    \
201	for (cur = map->buckets						    \
202		     ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
203		     : NULL;						    \
204	     cur && ({ tmp = cur->next; true; });			    \
205	     cur = tmp)							    \
206		if (map->equal_fn(cur->key, (_key), map->ctx))
207
208#endif /* __LIBBPF_HASHMAP_H */

  1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2
  3/*
  4 * Generic non-thread safe hash map implementation.
  5 *
  6 * Copyright (c) 2019 Facebook
  7 */
  8#ifndef __LIBBPF_HASHMAP_H
  9#define __LIBBPF_HASHMAP_H
 10
 11#include <stdbool.h>
 12#include <stddef.h>
 13#include <limits.h>
 14
 15static inline size_t hash_bits(size_t h, int bits)
 16{
 17	/* shuffle bits and return requested number of upper bits */
 18	if (bits == 0)
 19		return 0;
 20
 21#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
 22	/* LP64 case */
 23	return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
 24#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
 25	return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
 26#else
 27#	error "Unsupported size_t size"
 28#endif
 29}
 30
 31/* generic C-string hashing function */
 32static inline size_t str_hash(const char *s)
 33{
 34	size_t h = 0;
 35
 36	while (*s) {
 37		h = h * 31 + *s;
 38		s++;
 39	}
 40	return h;
 41}
 42
 43typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
 44typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
 45
 46/*
 47 * Hashmap interface is polymorphic, keys and values could be either
 48 * long-sized integers or pointers, this is achieved as follows:
 49 * - interface functions that operate on keys and values are hidden
 50 *   behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;
 51 * - these auxiliary macros cast the key and value parameters as
 52 *   long or long *, so the user does not have to specify the casts explicitly;
 53 * - for pointer parameters (e.g. old_key) the size of the pointed
 54 *   type is verified by hashmap_cast_ptr using _Static_assert;
 55 * - when iterating using hashmap__for_each_* forms
 56 *   hasmap_entry->key should be used for integer keys and
 57 *   hasmap_entry->pkey should be used for pointer keys,
 58 *   same goes for values.
 59 */
 60struct hashmap_entry {
 61	union {
 62		long key;
 63		const void *pkey;
 64	};
 65	union {
 66		long value;
 67		void *pvalue;
 68	};
 69	struct hashmap_entry *next;
 70};
 71
 72struct hashmap {
 73	hashmap_hash_fn hash_fn;
 74	hashmap_equal_fn equal_fn;
 75	void *ctx;
 76
 77	struct hashmap_entry **buckets;
 78	size_t cap;
 79	size_t cap_bits;
 80	size_t sz;
 81};
 82
 83void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
 84		   hashmap_equal_fn equal_fn, void *ctx);
 85struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
 86			     hashmap_equal_fn equal_fn,
 87			     void *ctx);
 88void hashmap__clear(struct hashmap *map);
 89void hashmap__free(struct hashmap *map);
 90
 91size_t hashmap__size(const struct hashmap *map);
 92size_t hashmap__capacity(const struct hashmap *map);
 93
 94/*
 95 * Hashmap insertion strategy:
 96 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
 97 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
 98 *   update value;
 99 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
100 *   nothing and return -ENOENT;
101 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
102 *   This turns hashmap into a multimap by allowing multiple values to be
103 *   associated with the same key. Most useful read API for such hashmap is
104 *   hashmap__for_each_key_entry() iteration. If hashmap__find() is still
105 *   used, it will return last inserted key/value entry (first in a bucket
106 *   chain).
107 */
108enum hashmap_insert_strategy {
109	HASHMAP_ADD,
110	HASHMAP_SET,
111	HASHMAP_UPDATE,
112	HASHMAP_APPEND,
113};
114
115#define hashmap_cast_ptr(p) ({								\
116	_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) ||			\
117				sizeof(*(p)) == sizeof(long),				\
118		       #p " pointee should be a long-sized integer or a pointer");	\
119	(long *)(p);									\
120})
121
122/*
123 * hashmap__insert() adds key/value entry w/ various semantics, depending on
124 * provided strategy value. If a given key/value pair replaced already
125 * existing key/value pair, both old key and old value will be returned
126 * through old_key and old_value to allow calling code do proper memory
127 * management.
128 */
129int hashmap_insert(struct hashmap *map, long key, long value,
130		   enum hashmap_insert_strategy strategy,
131		   long *old_key, long *old_value);
132
133#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
134	hashmap_insert((map), (long)(key), (long)(value), (strategy),  \
135		       hashmap_cast_ptr(old_key),		       \
136		       hashmap_cast_ptr(old_value))
137
138#define hashmap__add(map, key, value) \
139	hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
140
141#define hashmap__set(map, key, value, old_key, old_value) \
142	hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
143
144#define hashmap__update(map, key, value, old_key, old_value) \
145	hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
146
147#define hashmap__append(map, key, value) \
148	hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
149
150bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
151
152#define hashmap__delete(map, key, old_key, old_value)		       \
153	hashmap_delete((map), (long)(key),			       \
154		       hashmap_cast_ptr(old_key),		       \
155		       hashmap_cast_ptr(old_value))
156
157bool hashmap_find(const struct hashmap *map, long key, long *value);
158
159#define hashmap__find(map, key, value) \
160	hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
161
162/*
163 * hashmap__for_each_entry - iterate over all entries in hashmap
164 * @map: hashmap to iterate
165 * @cur: struct hashmap_entry * used as a loop cursor
166 * @bkt: integer used as a bucket loop cursor
167 */
168#define hashmap__for_each_entry(map, cur, bkt)				    \
169	for (bkt = 0; bkt < (map)->cap; bkt++)				    \
170		for (cur = (map)->buckets[bkt]; cur; cur = cur->next)
171
172/*
173 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
174 * against removals
175 * @map: hashmap to iterate
176 * @cur: struct hashmap_entry * used as a loop cursor
177 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
178 * @bkt: integer used as a bucket loop cursor
179 */
180#define hashmap__for_each_entry_safe(map, cur, tmp, bkt)		    \
181	for (bkt = 0; bkt < (map)->cap; bkt++)				    \
182		for (cur = (map)->buckets[bkt];				    \
183		     cur && ({tmp = cur->next; true; });		    \
184		     cur = tmp)
185
186/*
187 * hashmap__for_each_key_entry - iterate over entries associated with given key
188 * @map: hashmap to iterate
189 * @cur: struct hashmap_entry * used as a loop cursor
190 * @key: key to iterate entries for
191 */
192#define hashmap__for_each_key_entry(map, cur, _key)			    \
193	for (cur = (map)->buckets					    \
194		     ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
195		     : NULL;						    \
196	     cur;							    \
197	     cur = cur->next)						    \
198		if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
199
200#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key)		    \
201	for (cur = (map)->buckets					    \
202		     ? (map)->buckets[hash_bits((map)->hash_fn((_key), (map)->ctx), (map)->cap_bits)] \
203		     : NULL;						    \
204	     cur && ({ tmp = cur->next; true; });			    \
205	     cur = tmp)							    \
206		if ((map)->equal_fn(cur->key, (_key), (map)->ctx))
207
208#endif /* __LIBBPF_HASHMAP_H */