git.ozlabs.org Git - ccan/blob - ccan/htable/htable_type.h

   1 /* Licensed under LGPLv2+ - see LICENSE file for details */
   2 #ifndef CCAN_HTABLE_TYPE_H
   3 #define CCAN_HTABLE_TYPE_H
   4 #include <ccan/htable/htable.h>
   5 #include "config.h"
   6
   7 /**
   8  * HTABLE_DEFINE_TYPE - create a set of htable ops for a type
   9  * @type: a type whose pointers will be values in the hash.
  10  * @keyof: a function/macro to extract a key: <keytype> @keyof(const type *elem)
  11  * @hashfn: a hash function for a @key: size_t @hashfn(const <keytype> *)
  12  * @eqfn: an equality function keys: bool @eqfn(const type *, const <keytype> *)
  13  * @prefix: a prefix for all the functions to define (of form <name>_*)
  14  *
  15  * NULL values may not be placed into the hash table.
  16  *
  17  * This defines the type hashtable type and an iterator type:
  18  *      struct <name>;
  19  *      struct <name>_iter;
  20  *
  21  * It also defines initialization and freeing functions:
  22  *      void <name>_init(struct <name> *);
  23  *      void <name>_clear(struct <name> *);
  24  *
  25  * Add function only fails if we run out of memory:
  26  *      bool <name>_add(struct <name> *ht, const <type> *e);
  27  *
  28  * Delete and delete-by key return true if it was in the set:
  29  *      bool <name>_del(struct <name> *ht, const <type> *e);
  30  *      bool <name>_delkey(struct <name> *ht, const <keytype> *k);
  31  *
  32  * Find function return the matching element, or NULL:
  33  *      type *<name>_get(const struct @name *ht, const <keytype> *k);
  34  *
  35  * Iteration over hashtable is also supported:
  36  *      type *<name>_first(const struct <name> *ht, struct <name>_iter *i);
  37  *      type *<name>_next(const struct <name> *ht, struct <name>_iter *i);
  38  *
  39  * It's currently safe to iterate over a changing hashtable, but you might
  40  * miss an element.  Iteration isn't very efficient, either.
  41  */
  42 #define HTABLE_DEFINE_TYPE(type, keyof, hashfn, eqfn, name)             \
  43         struct name { struct htable raw; };                             \
  44         struct name##_iter { struct htable_iter i; };                   \
  45         static inline size_t name##_hash(const void *elem, void *priv)  \
  46         {                                                               \
  47                 return hashfn(keyof((const type *)elem));               \
  48         }                                                               \
  49         static inline void name##_init(struct name *ht)                 \
  50         {                                                               \
  51                 htable_init(&ht->raw, name##_hash, NULL);               \
  52         }                                                               \
  53         static inline void name##_clear(struct name *ht)                \
  54         {                                                               \
  55                 htable_clear(&ht->raw);                                 \
  56         }                                                               \
  57         static inline bool name##_add(struct name *ht, const type *elem) \
  58         {                                                               \
  59                 return htable_add(&ht->raw, hashfn(keyof(elem)), elem); \
  60         }                                                               \
  61         static inline bool name##_del(struct name *ht, const type *elem) \
  62         {                                                               \
  63                 return htable_del(&ht->raw, hashfn(keyof(elem)), elem); \
  64         }                                                               \
  65         static inline type *name##_get(const struct name *ht,           \
  66                                        const HTABLE_KTYPE(keyof) k)     \
  67         {                                                               \
  68                 /* Typecheck for eqfn */                                \
  69                 (void)sizeof(eqfn((const type *)NULL,                   \
  70                                   keyof((const type *)NULL)));          \
  71                 return htable_get(&ht->raw,                             \
  72                                   hashfn(k),                            \
  73                                   (bool (*)(const void *, void *))(eqfn), \
  74                                   k);                                   \
  75         }                                                               \
  76         static inline bool name##_delkey(struct name *ht,               \
  77                                          const HTABLE_KTYPE(keyof) k)   \
  78         {                                                               \
  79                 type *elem = name##_get(ht, k);                         \
  80                 if (elem)                                               \
  81                         return name##_del(ht, elem);                    \
  82                 return false;                                           \
  83         }                                                               \
  84         static inline type *name##_first(const struct name *ht,         \
  85                                          struct name##_iter *iter)      \
  86         {                                                               \
  87                 return htable_first(&ht->raw, &iter->i);                \
  88         }                                                               \
  89         static inline type *name##_next(const struct name *ht,          \
  90                                         struct name##_iter *iter)       \
  91         {                                                               \
  92                 return htable_next(&ht->raw, &iter->i);                 \
  93         }
  94
  95 #if HAVE_TYPEOF
  96 #define HTABLE_KTYPE(keyof) typeof(keyof(NULL))
  97 #else
  98 #define HTABLE_KTYPE(keyof) void *
  99 #endif
 100 #endif /* CCAN_HTABLE_TYPE_H */