hash.h

#ifndef MACHINATRIX_HASH_H
#define MACHINATRIX_HASH_H
 
#include <stddef.h>
#include <stdint.h>
 
#define MTRIX_HASHER_INIT ((struct mtrix_hasher){.h = 0x1505})
 
typedef uint64_t mtrix_hash;
 
struct mtrix_hasher {
    mtrix_hash h;
};
 
static inline struct mtrix_hasher mtrix_hasher_add(
    struct mtrix_hasher h, char b);
 
static inline struct mtrix_hasher mtrix_hasher_add_str(
    struct mtrix_hasher h, const char *s);
 
static inline struct mtrix_hasher mtrix_hasher_add_bytes(
    struct mtrix_hasher h, const void *p, size_t n);
 
static inline mtrix_hash mtrix_hash_str(const char *s);
 
static inline int mtrix_hash_cmp(const void *lhs, const void *rhs);
 
struct mtrix_hasher mtrix_hasher_add(struct mtrix_hasher h, char b) {
    return (struct mtrix_hasher){.h = ((h.h << 5) + h.h) + (uint64_t)b};
}
 
struct mtrix_hasher mtrix_hasher_add_str(
    struct mtrix_hasher h, const char *s
) {
    for(char c; (c = *s++);)
        h = mtrix_hasher_add(h, c);
    return h;
}
 
struct mtrix_hasher mtrix_hasher_add_bytes(
    struct mtrix_hasher h, const void *vp, size_t n
) {
    for(const char *p = vp; n--;)
        h = mtrix_hasher_add(h, *p++);
    return h;
}
 
mtrix_hash mtrix_hash_str(const char *s) {
    return mtrix_hasher_add_str(MTRIX_HASHER_INIT, s).h;
}
 
int mtrix_hash_cmp(const void *lhs_p, const void *rhs_p) {
    const mtrix_hash lhs = *(const mtrix_hash*)lhs_p;
    const mtrix_hash rhs = *(const mtrix_hash*)rhs_p;
    return lhs < rhs ? -1 : rhs < lhs ? 1 : 0;
}
 
#endif