Fumofumotris/rewrite/c/dictionary.c

#include "dictionary.h"
#include <string.h>


void *index_bkt(struct Dictionary *dict, usize i)
{
	return (u8 *)dict->bkts + i * dict->bkt_size;
}

u32 *get_key(struct Dictionary *dict, void *bkt)
{
	return (u32 *)bkt;
}

void *get_value_ptr(struct Dictionary *dict, void *bkt)
{
	return (u8 *)bkt + dict->value_offset;
}

void set_bkt(struct Dictionary *dict, void *bkt, u32 key, void *value_ptr)
{
	*get_key(dict, bkt) = key;
	memcpy(get_value_ptr(dict, bkt), value_ptr, dict->value_size);
}

void *probe_bkt(struct Dictionary *dict, usize index, u32 key)
{
	for (usize i = 0; i < dict->capacity; i++) {
		void *bkt = index_bkt(dict, (index + i) % dict->capacity);

		if (*get_key(dict, bkt) == key)
			return bkt;
	}

	return nullptr;
}

void *probe_empty_bkt(struct Dictionary *dict, usize index, u32 key)
{
	for (usize i = 0; i < dict->capacity; i++) {
		void *bkt = index_bkt(dict, (index + i) % dict->capacity);

		u32 k = *get_key(dict, bkt);
		if (k == 0 or k == key)
			return bkt;
	}

	return nullptr;
}

void *DictionaryFind(struct Dictionary *dict, u32 key)
{
	usize index = key % dict->capacity;

	void *bkt = probe_bkt(dict, index, key);
	if (bkt == nullptr)
		return false;

	return get_value_ptr(dict, bkt);
}

void *DictionarySet(struct Dictionary *dict, u32 key, void *value_ptr)
{
	usize index = key % dict->capacity;

	void *bkt = probe_empty_bkt(dict, index, key);

	if (*get_key(dict, bkt) == 0) 
		set_bkt(dict, bkt, key, value_ptr);

	return bkt;
}