diff options
Diffstat (limited to 'libihash/ihash.h')
| -rw-r--r-- | libihash/ihash.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/libihash/ihash.h b/libihash/ihash.h index 128027a0..1dbc3483 100644 --- a/libihash/ihash.h +++ b/libihash/ihash.h @@ -26,6 +26,7 @@ #include <sys/types.h> #include <limits.h> #include <stdint.h> +#include <stddef.h> /* The type of the values corresponding to the keys. Must be a @@ -198,10 +199,61 @@ hurd_ihash_get_load (hurd_ihash_t ht) error_t hurd_ihash_add (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t item); +/* Add VALUE to the hash table HT under the key KEY at LOCP. If there + already is an item under this key, call the cleanup function (if + any) for it before overriding the value. This function is faster + than hurd_ihash_add. + + If LOCP is NULL, fall back to hurd_ihash_add. Otherwise, LOCP must + be valid and may either be obtained from hurd_ihash_locp_find, or + from an item that is currently in the hash table. If an item is + replaced, KEY must match the key of the previous item. + + If a memory allocation error occurs, ENOMEM is returned, otherwise + 0. */ +error_t hurd_ihash_locp_add (hurd_ihash_t ht, hurd_ihash_locp_t locp, + hurd_ihash_key_t key, hurd_ihash_value_t value); + /* Find and return the item in the hash table HT with key KEY, or NULL if it doesn't exist. */ hurd_ihash_value_t hurd_ihash_find (hurd_ihash_t ht, hurd_ihash_key_t key); +/* Find the item in the hash table HT with key KEY. If it is found, + return the location of its slot in the hash table. If it is not + found, this function may still return a location. + + This location pointer can always be safely accessed using + hurd_ihash_locp_value. If the lookup is successful, + hurd_ihash_locp_value will return the value related to KEY. + + If the lookup is successful, the returned location can be used with + hurd_ihash_locp_add to update the item, and with + hurd_ihash_locp_remove to remove it. + + If the lookup is not successful, the returned location can be used + with hurd_ihash_locp_add to add the item. + + Note that returned location is only valid until the next insertion + or deletion. */ +hurd_ihash_locp_t hurd_ihash_locp_find (hurd_ihash_t ht, + hurd_ihash_key_t key); + +/* Given an hash table bucket location LOCP, return the value stored + there, or NULL if it is empty or LOCP is NULL. */ +static inline void * +hurd_ihash_locp_value (hurd_ihash_locp_t locp) +{ + struct _hurd_ihash_item *item = (struct _hurd_ihash_item *) locp; + + if (item == NULL) + return NULL; + + if (hurd_ihash_value_valid (item->value)) + return item->value; + + return NULL; +} + /* Iterate over all elements in the hash table. You use this macro with a block, for example like this: |