Question

I’m looking for a hashtable implementation in C that stores its objects in (twodimensional) arrays rather than linked lists.
i.e. if a collision happens, the object that is causing the collision will be stored in the next free row index rather than pushed to the head and first element of a linked list.

plus, the objects themselves must be copied to the hashtable, rather than referenced by pointers. (the objects do not live for the whole lifetime of the program but the table does).

I know that such an implementation might have serious efficiency drawbacks and is not the “standard way of hashing” but as I work on a very special system-architecture i need those characteristics.

thanks

Answer 1

A super simple implementation:

char hashtable[MAX_KEY][MAX_MEMORY];
int counts[MAX_KEY] = {0}; 

/* Inserting something into the table */
SomeStruct* some_struct;
int hashcode = compute_code(some_struct);
int size = sizeof(SomeStruct); 
memcpy(hashtable[hashcode] + counts[hashcode] * size, some_struct, size);
++counts[hashcode];

Don’t forget to check against MAX_MEMORY.