The hash API is a collection of simple hash table functions. Users are expected to implement their own hashing.

Data Structures

struct hash_table

The hash table structure. The array member points to the hash table entries. The size member counts the total number of valid and invalid entries in the table. The nr member keeps track of the number of valid entries.

struct hash_table_entry

An opaque structure representing an entry in the hash table. The hash member is the entry’s hash key and the ptr member is the entry’s value.

Functions

init_hash

Initialize the hash table.

free_hash

Release memory associated with the hash table.

insert_hash

Insert a pointer into the hash table. If an entry with that hash already exists, a pointer to the existing entry’s value is returned. Otherwise NULL is returned. This allows callers to implement chaining, etc.

lookup_hash

Lookup an entry in the hash table. If an entry with that hash exists the entry’s value is returned. Otherwise NULL is returned.

for_each_hash

Call a function for each entry in the hash table. The function is expected to take the entry’s value as its only argument and return an int. If the function returns a negative int the loop is aborted immediately. Otherwise, the return value is accumulated and the sum returned upon completion of the loop.