raze/source/build/include/hash.h
terminx 0af13dcde0 Minor changes to hash table code
git-svn-id: https://svn.eduke32.com/eduke32@8372 1a8010ca-5511-0410-912e-c29ae57300e0

# Conflicts:
#	source/build/include/hash.h
2019-12-08 08:09:13 +01:00

85 lines
2.1 KiB
C

#pragma once
#ifndef hash_h_
#define hash_h_
// Hash functions
#define DJB_MAGIC 5381u
typedef struct hashitem // size is 12/24 bytes.
{
char *string;
intptr_t key;
struct hashitem *next;
} hashitem_t;
typedef struct
{
int32_t size;
hashitem_t **items;
} hashtable_t;
// djb3 algorithm
static inline uint32_t hash_getcode(const char *s)
{
uint32_t h = DJB_MAGIC;
char ch;
while ((ch = Btolower(*s++)) != '\0')
h = ((h << 5) + h) ^ ch;
return h;
}
void hash_init(hashtable_t *t);
void hash_loop(hashtable_t *t, void (*func)(const char *, intptr_t));
void hash_free(hashtable_t *t);
void hash_add(hashtable_t *t, const char *s, intptr_t key, int32_t replace);
void hash_delete(hashtable_t *t, const char *s);
intptr_t hash_findcase(hashtable_t const *t, char const *s);
intptr_t hash_find(hashtable_t const *t, char const *s);
// Hash functions
// modified for raw binary keys and one big allocation, and maximum find() performance
typedef struct inthashitem
{
intptr_t key;
intptr_t value;
struct inthashitem *collision; // use NULL to signify empty and pointer identity to signify end of linked list
} inthashitem_t;
typedef struct
{
inthashitem_t *items;
uint32_t count;
} inthashtable_t;
// djb3 algorithm
static inline uint32_t inthash_getcode(intptr_t key)
{
uint32_t h = DJB_MAGIC;
for (auto keybuf = (uint8_t const *) &key, keybuf_end = keybuf + sizeof(key); keybuf < keybuf_end; ++keybuf)
h = ((h << 5) + h) ^ (uint32_t) *keybuf;
return h;
}
void inthash_init(inthashtable_t *t);
void inthash_loop(inthashtable_t const *t, void (*func)(intptr_t, intptr_t));
void inthash_free(inthashtable_t *t);
void inthash_add(inthashtable_t *t, intptr_t key, intptr_t value, int32_t replace);
void inthash_delete(inthashtable_t *t, intptr_t key);
intptr_t inthash_find(inthashtable_t const *t, intptr_t key);
// keep the load factor below 0.75 and make sure the size is odd
// ideally we would find the next largest prime number
#define INTHASH_SIZE(size) ((size * 4u / 3u) | 1u)
#endif
#endif // hash_h_