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Alessandro Mauri 2023-11-02 11:25:53 +01:00
parent 4ee957c2ae
commit 71080476b1
54 changed files with 219 additions and 22797 deletions
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generic_hash.h Normal file
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#ifndef _HASH_GENERIC
#define _HASH_GENERIC
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
// FIXME: change the api to just one HASH_DECL to HASH_PROTO and HASH_DEFINE
#define HASH_MAXSIZE 4096
// for fibonacci hashing, 2^{32,64}/<golden ratio>
#define HASH_RATIO32 ((uint64_t)2654435769u)
#define HASH_RATIO64 ((uint64_t)11400714819322457583u)
// salt for string hashing
#define HASH_SALT ((uint64_t)0xbabb0cac)
/* Ready-made compares */
static inline int hash_cmp_u32(uint32_t a, uint32_t b) { return a == b; }
static inline int hash_cmp_u64(uint64_t a, uint64_t b) { return a == b; }
static inline int hash_cmp_str(const char *a, const char *b) { return strcmp(a, b) == 0; }
/* Ready-made hashes */
static inline uint32_t hash_u64(uint64_t c)
{
return (uint64_t)((((uint64_t)c+HASH_SALT)*HASH_RATIO64)>>32);
}
static inline uint32_t hash_u32(uint32_t c)
{
return (uint32_t)((((uint64_t)c<<31)*HASH_RATIO64)>>32);
}
static inline uint32_t hash_str(const char *s)
{
uint32_t h = HASH_SALT;
const uint8_t *v = (const uint8_t *)(s);
for (int x = *s; x; x--) {
h += v[x-1];
h += h << 10;
h ^= h >> 6;
}
h += h << 3;
h ^= h >> 11;
h += h << 15;
return h;
}
#define HASH_DECL(htname, codetype, datatype, hashfn, cmpfn) \
struct htname##_entry { \
codetype code; \
datatype data; \
}; \
\
struct htname##_ref { \
uint32_t items, size, exp; \
struct htname##_entry bucket[]; \
}; \
\
\
struct htname##_ref * htname##_create(uint32_t size) \
{ \
if (!size || size > HASH_MAXSIZE) \
return NULL; \
/* round to the greater power of two */ \
/* FIXME: check for intger overflow here */ \
uint32_t exp = 32-__builtin_clz(size-1); \
size = 1<<(exp); \
/* FIXME: check for intger overflow here */ \
struct htname##_ref *ht = malloc(sizeof(struct htname##_ref)+sizeof(struct htname##_entry)*size); \
if (ht) { \
ht->items = 0; \
ht->size = size; \
ht->exp = exp; \
memset(ht->bucket, 0, sizeof(struct htname##_entry)*size); \
} \
return ht; \
} \
\
\
void htname##_destroy(struct htname##_ref *ht) \
{ \
if (ht) free(ht); \
} \
\
\
static uint32_t htname##_lookup(struct htname##_ref *ht, uint32_t hash, uint32_t idx) \
{ \
if (!ht) return 0; \
uint32_t mask = ht->size-1; \
uint32_t step = (hash >> (32 - ht->exp)) | 1; \
return (idx + step) & mask; \
} \
\
\
/* Find and return the element by code */ \
struct htname##_entry * htname##_search(struct htname##_ref *ht, codetype code)\
{ \
if (!ht) return NULL; \
uint32_t h = hashfn(code); \
for (uint32_t i=h, x=0; ; x++) { \
i = htname##_lookup(ht, h, i); \
if (x > (ht->size<<1) || \
!ht->bucket[i].code || \
cmpfn(ht->bucket[i].code, code) \
) { \
return &(ht->bucket[i]); \
} \
} \
return NULL; \
} \
\
\
/* FIXME: this simply overrides the found item */ \
struct htname##_entry * htname##_insert(struct htname##_ref *ht, struct htname##_entry *entry) \
{ \
struct htname##_entry *r = htname##_search(ht, entry->code); \
if (r) { \
if (!r->code) \
ht->items++; \
*r = *entry; \
} \
return r; \
} \
\
\
struct htname##_entry * htname##_remove(struct htname##_ref *ht, codetype code)\
{ \
if (!ht) return NULL; \
struct htname##_entry *r = htname##_search(ht, code); \
if (r) r->code = 0; \
return r; \
} \
#endif