fnv1a.h File Reference

#include <stdint.h>
#include <derive-c/core/prelude.h>
#include <derive-c/core/std/reflect.h>

Go to the source code of this file.

Macros
#define	DC_FNV1A_64_OFFSET   14695981039346656037ull
	FNV-1a 64-bit constants.
#define	DC_FNV1A_64_PRIME   1099511628211ull
#define	FNV1A_INTEGER(type, ...)
	Applying the fnv1a hash for the size of the integer.

Functions
static DC_PUBLIC uint64_t	dc_fnv1a_str_borrow (const char *s)
	Hashes a null terminated string.
static DC_PUBLIC uint64_t	dc_fnv1a_str (char *const *s)
static DC_PUBLIC uint64_t	dc_fnv1a_str_const (const char *const *s)
static DC_PUBLIC uint64_t	dc_fnv1a_u64 (uint64_t const *v)
static DC_PUBLIC uint64_t	dc_fnv1a_u32 (uint32_t const *v)

Macro Definition Documentation

DC_FNV1A_64_OFFSET

#define DC_FNV1A_64_OFFSET   14695981039346656037ull

FNV-1a 64-bit constants.

Definition at line 9 of file fnv1a.h.

DC_FNV1A_64_PRIME

#define DC_FNV1A_64_PRIME   1099511628211ull

Definition at line 10 of file fnv1a.h.

FNV1A_INTEGER

#define FNV1A_INTEGER	(		type,
			... )

Value:

    DC_PUBLIC static size_t type##_hash_fnv1a(type const* key) {                                   \
        DC_STATIC_ASSERT(sizeof(type) <= sizeof(uint64_t),                                         \
                         "fnv integer hashing only supports up to size_t integers");               \
        if (sizeof(type) <= sizeof(uint32_t)) {                                                    \
            uint32_t value = (uint32_t)(*key);                                                     \
            return dc_fnv1a_u32(&value);                                                           \
        }                                                                                          \
        uint64_t value = (uint64_t)(*key);                                                         \
        return dc_fnv1a_u64(&value);                                                               \
    }

Applying the fnv1a hash for the size of the integer.

Definition at line 55 of file fnv1a.h.

#define FNV1A_INTEGER(type, ...)                                                                   \
    DC_PUBLIC static size_t type##_hash_fnv1a(type const* key) {                                   \
        DC_STATIC_ASSERT(sizeof(type) <= sizeof(uint64_t),                                         \
                         "fnv integer hashing only supports up to size_t integers");               \
        if (sizeof(type) <= sizeof(uint32_t)) {                                                    \
            uint32_t value = (uint32_t)(*key);                                                     \
            return dc_fnv1a_u32(&value);                                                           \
        }                                                                                          \
        uint64_t value = (uint64_t)(*key);                                                         \
        return dc_fnv1a_u64(&value);                                                               \
    }

Function Documentation

dc_fnv1a_str()

DC_PUBLIC uint64_t dc_fnv1a_str ( char *const * s )

inlinestatic

Definition at line 24 of file fnv1a.h.

{ return dc_fnv1a_str_borrow(*s); }

dc_fnv1a_str_borrow()

DC_PUBLIC uint64_t dc_fnv1a_str_borrow ( const char * s )

inlinestatic

Hashes a null terminated string.

Definition at line 13 of file fnv1a.h.

                                                                    {
    const unsigned char* p = (const unsigned char*)(s);
    uint64_t h = DC_FNV1A_64_OFFSET;
 
    for (unsigned char c = *p; c != 0; c = *++p) {
        h ^= (uint64_t)c;
        h *= DC_FNV1A_64_PRIME;
    }
    return h;
}

dc_fnv1a_str_const()

DC_PUBLIC uint64_t dc_fnv1a_str_const ( const char *const * s )

inlinestatic

Examples

container/map.c, and container/set.c.

Definition at line 26 of file fnv1a.h.

                                                                          {
    return dc_fnv1a_str_borrow(*s);
}

dc_fnv1a_u32()

DC_PUBLIC uint64_t dc_fnv1a_u32 ( uint32_t const * v )

inlinestatic

Definition at line 42 of file fnv1a.h.

                                                                 {
    uint64_t h = DC_FNV1A_64_OFFSET;
    uint32_t x = *v;
 
    for (int i = 0; i < 4; ++i) {
        h ^= (uint64_t)(x & 0xffU);
        h *= DC_FNV1A_64_PRIME;
        x >>= 8;
    }
    return h;
}

dc_fnv1a_u64()

DC_PUBLIC uint64_t dc_fnv1a_u64 ( uint64_t const * v )

inlinestatic

Definition at line 30 of file fnv1a.h.

                                                                 {
    uint64_t h = DC_FNV1A_64_OFFSET;
    uint64_t x = *v;
 
    for (int i = 0; i < 8; ++i) {
        h ^= (uint64_t)(x & 0xffU);
        h *= DC_FNV1A_64_PRIME;
        x >>= 8;
    }
    return h;
}