tools/perf/util/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
  15 static inline size_t hash_bits(size_t h, int bits)
  16 {
  17         /* shuffle bits and return requested number of upper bits */
  18 #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
  19         /* LP64 case */
  20         return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
  21 #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
  22         return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
  23 #else
  24 #       error "Unsupported size_t size"
  25 #endif
  26 }
  27
  28 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
  29 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
  30
  31 struct hashmap_entry {
  32         const void *key;
  33         void *value;
  34         struct hashmap_entry *next;
  35 };
  36
  37 struct hashmap {
  38         hashmap_hash_fn hash_fn;
  39         hashmap_equal_fn equal_fn;
  40         void *ctx;
  41
  42         struct hashmap_entry **buckets;
  43         size_t cap;
  44         size_t cap_bits;
  45         size_t sz;
  46 };
  47
  48 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) {  \
  49         .hash_fn = (hash_fn),                   \
  50         .equal_fn = (equal_fn),                 \
  51         .ctx = (ctx),                           \
  52         .buckets = NULL,                        \
  53         .cap = 0,                               \
  54         .cap_bits = 0,                          \
  55         .sz = 0,                                \
  56 }
  57
  58 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
  59                    hashmap_equal_fn equal_fn, void *ctx);
  60 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
  61                              hashmap_equal_fn equal_fn,
  62                              void *ctx);
  63 void hashmap__clear(struct hashmap *map);
  64 void hashmap__free(struct hashmap *map);
  65
  66 size_t hashmap__size(const struct hashmap *map);
  67 size_t hashmap__capacity(const struct hashmap *map);
  68
  69 /*
  70  * Hashmap insertion strategy:
  71  * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
  72  * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
  73  *   update value;
  74  * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
  75  *   nothing and return -ENOENT;
  76  * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
  77  *   This turns hashmap into a multimap by allowing multiple values to be
  78  *   associated with the same key. Most useful read API for such hashmap is
  79  *   hashmap__for_each_key_entry() iteration. If hashmap__find() is still
  80  *   used, it will return last inserted key/value entry (first in a bucket
  81  *   chain).
  82  */
  83 enum hashmap_insert_strategy {
  84         HASHMAP_ADD,
  85         HASHMAP_SET,
  86         HASHMAP_UPDATE,
  87         HASHMAP_APPEND,
  88 };
  89
  90 /*
  91  * hashmap__insert() adds key/value entry w/ various semantics, depending on
  92  * provided strategy value. If a given key/value pair replaced already
  93  * existing key/value pair, both old key and old value will be returned
  94  * through old_key and old_value to allow calling code do proper memory
  95  * management.
  96  */
  97 int hashmap__insert(struct hashmap *map, const void *key, void *value,
  98                     enum hashmap_insert_strategy strategy,
  99                     const void **old_key, void **old_value);
 100
 101 static inline int hashmap__add(struct hashmap *map,
 102                                const void *key, void *value)
 103 {
 104         return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
 105 }
 106
 107 static inline int hashmap__set(struct hashmap *map,
 108                                const void *key, void *value,
 109                                const void **old_key, void **old_value)
 110 {
 111         return hashmap__insert(map, key, value, HASHMAP_SET,
 112                                old_key, old_value);
 113 }
 114
 115 static inline int hashmap__update(struct hashmap *map,
 116                                   const void *key, void *value,
 117                                   const void **old_key, void **old_value)
 118 {
 119         return hashmap__insert(map, key, value, HASHMAP_UPDATE,
 120                                old_key, old_value);
 121 }
 122
 123 static inline int hashmap__append(struct hashmap *map,
 124                                   const void *key, void *value)
 125 {
 126         return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
 127 }
 128
 129 bool hashmap__delete(struct hashmap *map, const void *key,
 130                      const void **old_key, void **old_value);
 131
 132 bool hashmap__find(const struct hashmap *map, const void *key, void **value);
 133
 134 /*
 135  * hashmap__for_each_entry - iterate over all entries in hashmap
 136  * @map: hashmap to iterate
 137  * @cur: struct hashmap_entry * used as a loop cursor
 138  * @bkt: integer used as a bucket loop cursor
 139  */
 140 #define hashmap__for_each_entry(map, cur, bkt)                              \
 141         for (bkt = 0; bkt < map->cap; bkt++)                                \
 142                 for (cur = map->buckets[bkt]; cur; cur = cur->next)
 143
 144 /*
 145  * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
 146  * against removals
 147  * @map: hashmap to iterate
 148  * @cur: struct hashmap_entry * used as a loop cursor
 149  * @tmp: struct hashmap_entry * used as a temporary next cursor storage
 150  * @bkt: integer used as a bucket loop cursor
 151  */
 152 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt)                    \
 153         for (bkt = 0; bkt < map->cap; bkt++)                                \
 154                 for (cur = map->buckets[bkt];                               \
 155                      cur && ({tmp = cur->next; true; });                    \
 156                      cur = tmp)
 157
 158 /*
 159  * hashmap__for_each_key_entry - iterate over entries associated with given key
 160  * @map: hashmap to iterate
 161  * @cur: struct hashmap_entry * used as a loop cursor
 162  * @key: key to iterate entries for
 163  */
 164 #define hashmap__for_each_key_entry(map, cur, _key)                         \
 165         for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
 166                                              map->cap_bits);                \
 167                      map->buckets ? map->buckets[bkt] : NULL; });           \
 168              cur;                                                           \
 169              cur = cur->next)                                               \
 170                 if (map->equal_fn(cur->key, (_key), map->ctx))
 171
 172 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key)               \
 173         for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
 174                                              map->cap_bits);                \
 175                      cur = map->buckets ? map->buckets[bkt] : NULL; });     \
 176              cur && ({ tmp = cur->next; true; });                           \
 177              cur = tmp)                                                     \
 178                 if (map->equal_fn(cur->key, (_key), map->ctx))
 179
 180 #endif /* __LIBBPF_HASHMAP_H */