mirror of
https://github.com/DarkPlacesEngine/gmqcc.git
synced 2025-01-21 07:30:53 +00:00
hash cleanups.
This commit is contained in:
Dale Weiler
parent
f24bdced10
commit
7e88247ed5
1 changed files with 91 additions and 157 deletions
250
hash.c
250
hash.c
|
|
@ -23,9 +23,21 @@
|
|||
#include "gmqcc.h"
|
||||
#include <limits.h>
|
||||
|
||||
#if defined(_MSC_VER)
|
||||
# define HASH_ROTL32(X, Y) _rotl((X), (Y))
|
||||
#elif defined (__GNUC__) && (defined(__i386__) || defined(__amd64__))
|
||||
static GMQCC_FORCEINLINE uint32_t hash_rotl32(volatile uint32_t x, int8_t r) {
|
||||
__asm__ __volatile__ ("roll %1,%0" : "+r"(x) : "c"(r));
|
||||
return x;
|
||||
}
|
||||
# define HASH_ROTL32(X, Y) hash_rotl32((volatile uint32_t)(X), (Y))
|
||||
#else
|
||||
# define HASH_ROTL32(X, Y) (((X) << (Y)) | ((X) >> (32 - (Y))))
|
||||
#endif
|
||||
|
||||
/*
|
||||
* This is a version of the Murmur3 hashing function optimized for various
|
||||
* compilers/architectures. It uses the traditional Murmur2 mix stagin
|
||||
* compilers/architectures. It uses the traditional Murmur2 mix staging
|
||||
* but fixes the mix staging inner loops.
|
||||
*
|
||||
* Murmur 2 contains an inner loop such as:
|
||||
|
|
@ -67,28 +79,7 @@
|
|||
* This means we have a 14.5% higher chance of collision. This is where
|
||||
* Murmur3 comes in to save the day.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Some rotation tricks:
|
||||
* MSVC one shaves off six instructions, where GCC optimized one for
|
||||
* x86 and amd64 shaves off four instructions. Native methods are often
|
||||
* optimized rather well at -O3, but not at -O2.
|
||||
*/
|
||||
#if defined(_MSC_VER)
|
||||
# define HASH_ROTL32(X, Y) _rotl((X), (Y))
|
||||
#else
|
||||
static GMQCC_FORCEINLINE uint32_t hash_rotl32(volatile uint32_t x, int8_t r) {
|
||||
#if defined (__GNUC__) && (defined(__i386__) || defined(__amd64__))
|
||||
__asm__ __volatile__ ("roll %1,%0" : "+r"(x) : "c"(r));
|
||||
return x;
|
||||
#else /* ! (defined(__GNUC__) && (defined(__i386__) || defined(__amd64__))) */
|
||||
return (x << r) | (x >> (32 - r));
|
||||
#endif
|
||||
}
|
||||
# define HASH_ROTL32(X, Y) hash_rotl32((volatile uint32_t)(X), (Y))
|
||||
#endif /* !(_MSC_VER) */
|
||||
|
||||
static GMQCC_FORCEINLINE uint32_t hash_mix32(uint32_t hash) {
|
||||
static GMQCC_FORCEINLINE uint32_t hash_murmur_mix32(uint32_t hash) {
|
||||
hash ^= hash >> 16;
|
||||
hash *= 0x85EBCA6B;
|
||||
hash ^= hash >> 13;
|
||||
|
|
@ -102,33 +93,33 @@ static GMQCC_FORCEINLINE uint32_t hash_mix32(uint32_t hash) {
|
|||
* case senario for Murmur3:
|
||||
* http://code.google.com/p/smhasher/
|
||||
*/
|
||||
#define HASH_MASK1 0xCC9E2D51
|
||||
#define HASH_MASK2 0x1B873593
|
||||
#define HASH_SEED 0x9747B28C
|
||||
#define HASH_MURMUR_MASK1 0xCC9E2D51
|
||||
#define HASH_MURMUR_MASK2 0x1B873593
|
||||
#define HASH_MURMUR_SEED 0x9747B28C
|
||||
|
||||
#if PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_LITTLE
|
||||
# define HASH_NATIVE_SAFEREAD(PTR) (*((uint32_t*)(PTR)))
|
||||
# define HASH_MURMUR_SAFEREAD(PTR) (*((uint32_t*)(PTR)))
|
||||
#elif PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_BIG
|
||||
# if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR >= 3))
|
||||
# define HASH_NATIVE_SAFEREAD(PTR) (__builtin_bswap32(*((uint32_t*)(PTR))))
|
||||
# define HASH_MURMUR_SAFEREAD(PTR) (__builtin_bswap32(*((uint32_t*)(PTR))))
|
||||
# endif
|
||||
#endif
|
||||
/* Process individual bytes at this point since the endianess isn't known. */
|
||||
#ifndef HASH_NATIVE_SAFEREAD
|
||||
# define HASH_NATIVE_SAFEREAD(PTR) ((PTR)[0] | (PTR)[1] << 8 | (PTR)[2] << 16 | (PTR)[3] << 24)
|
||||
#ifndef HASH_MURMUR_SAFEREAD
|
||||
# define HASH_MURMUR_SAFEREAD(PTR) ((PTR)[0] | (PTR)[1] << 8 | (PTR)[2] << 16 | (PTR)[3] << 24)
|
||||
#endif
|
||||
|
||||
#define HASH_NATIVE_BLOCK(H, K) \
|
||||
#define HASH_MURMUR_BLOCK(H, K) \
|
||||
do { \
|
||||
K *= HASH_MASK1; \
|
||||
K *= HASH_MURMUR_MASK1; \
|
||||
K = HASH_ROTL32(K, 15); \
|
||||
K *= HASH_MASK2; \
|
||||
K *= HASH_MURMUR_MASK2; \
|
||||
H ^= K; \
|
||||
H = HASH_ROTL32(H, 13); \
|
||||
H = H * 5 + 0xE6546B64; \
|
||||
} while (0)
|
||||
|
||||
#define HASH_NATIVE_BYTES(COUNT, H, C, N, PTR, LENGTH) \
|
||||
#define HASH_MURMUR_BYTES(COUNT, H, C, N, PTR, LENGTH) \
|
||||
do { \
|
||||
int i = COUNT; \
|
||||
while (i--) { \
|
||||
|
|
@ -136,175 +127,118 @@ static GMQCC_FORCEINLINE uint32_t hash_mix32(uint32_t hash) {
|
|||
N++; \
|
||||
LENGTH--; \
|
||||
if (N == 4) { \
|
||||
HASH_NATIVE_BLOCK(H, C); \
|
||||
HASH_MURMUR_BLOCK(H, C); \
|
||||
N = 0; \
|
||||
} \
|
||||
} \
|
||||
} while (0)
|
||||
|
||||
/*
|
||||
* Highly unrolled at per-carry bit granularity instead of per-block granularity. This will achieve the
|
||||
* highest possible instruction level parallelism.
|
||||
*/
|
||||
static GMQCC_FORCEINLINE void hash_native_process(uint32_t *ph1, uint32_t *carry, const void *key, int length) {
|
||||
#if PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_LITTLE
|
||||
static GMQCC_FORCEINLINE void hash_murmur_process(uint32_t *ph1, uint32_t *carry, const void *key, int length) {
|
||||
uint32_t h1 = *ph1;
|
||||
uint32_t c = *carry;
|
||||
|
||||
const uint8_t *ptr = (uint8_t*)key;
|
||||
const uint8_t *end;
|
||||
|
||||
/* carry count from low 2 bits of carry value */
|
||||
int n = c & 3;
|
||||
|
||||
/*
|
||||
* Unaligned word accesses are safe in LE. Thus we can obtain a little
|
||||
* more speed.
|
||||
*/
|
||||
# if PLATFORM_BYTE_ORDER == GMQCC_BYTE_ORDER_LITTLE
|
||||
/* Consume carry bits */
|
||||
int it = (4 - n) & 3;
|
||||
if (it && it <= length)
|
||||
HASH_NATIVE_BYTES(it, h1, c, n, ptr, length);
|
||||
HASH_MURMUR_BYTES(it, h1, c, n, ptr, length);
|
||||
|
||||
/* word size chunk consumption */
|
||||
end = ptr + length/4*4;
|
||||
for (; ptr < end; ptr += 4) {
|
||||
uint32_t k1 = HASH_NATIVE_SAFEREAD(ptr);
|
||||
HASH_NATIVE_BLOCK(h1, k1);
|
||||
uint32_t k1 = HASH_MURMUR_SAFEREAD(ptr);
|
||||
HASH_MURMUR_BLOCK(h1, k1);
|
||||
}
|
||||
# else
|
||||
/*
|
||||
* Unsafe to assume unaligned word accesses. Thus we'll need to consume
|
||||
* to alignment then process in aligned block chunks.
|
||||
*/
|
||||
uint32_t k1;
|
||||
int it = -(long)ptr & 3;
|
||||
if (it && it <= length)
|
||||
HASH_NATIVE_BYTES(it, h1, c, n, ptr, length);
|
||||
|
||||
/*
|
||||
* Alignment has been reached, deal with aligned blocks, specializing for
|
||||
* all possible carry counts.
|
||||
*/
|
||||
end = ptr + length / 4 * 4;
|
||||
switch (n) {
|
||||
case 0:
|
||||
for (; ptr < end; ptr += 4) {
|
||||
k1 = HASH_NATIVE_SAFEREAD(ptr);
|
||||
HASH_NATIVE_BLOCK(h1, k1);
|
||||
}
|
||||
break;
|
||||
|
||||
case 1:
|
||||
for (; ptr < end; ptr += 4) {
|
||||
k1 = c >> 24;
|
||||
c = HASH_NATIVE_SAFEREAD(ptr);
|
||||
k1 |= c << 8;
|
||||
HASH_NATIVE_BLOCK(h1, k1);
|
||||
}
|
||||
break;
|
||||
|
||||
case 2:
|
||||
for (; ptr < end; ptr += 4) {
|
||||
k1 = c >> 16;
|
||||
c = HASH_NATIVE_SAFEREAD(ptr);
|
||||
k1 |= c << 16;
|
||||
HASH_NATIVE_BLOCK(h1, k1);
|
||||
}
|
||||
break;
|
||||
|
||||
case 3:
|
||||
for (; ptr < end; ptr += 4) {
|
||||
k1 = c >> 8;
|
||||
c = HASH_NATIVE_SAFEREAD(ptr);
|
||||
k1 |= c << 24;
|
||||
HASH_NATIVE_BLOCK(h1, k1);
|
||||
}
|
||||
break;
|
||||
}
|
||||
#endif /* misaligned reads */
|
||||
|
||||
/*
|
||||
* Advanced over 32-bit chunks, this can possibly leave 1..3 bytes of
|
||||
* additional trailing content to process.
|
||||
*/
|
||||
length -= length/4*4;
|
||||
|
||||
HASH_NATIVE_BYTES(length, h1, c, n, ptr, length);
|
||||
HASH_MURMUR_BYTES(length, h1, c, n, ptr, length);
|
||||
|
||||
*ph1 = h1;
|
||||
*carry = (c & ~0xFF) | n;
|
||||
}
|
||||
#else
|
||||
static GMQCC_FORCEINLINE void hash_murmur_process(uint32_t *ph1, uint32_t *carry, const void *key, int length) {
|
||||
uint32_t k1;
|
||||
uint32_t h1 = *ph1;
|
||||
uint32_t c = *carry;
|
||||
|
||||
static GMQCC_FORCEINLINE uint32_t hash_native_result(uint32_t hash, uint32_t carry, size_t length) {
|
||||
const uint8_t *ptr = (uint8_t*)key;
|
||||
const uint8_t *end;
|
||||
|
||||
int n = c & 3;
|
||||
int it = -(long)ptr & 3;
|
||||
if (it && it <= length)
|
||||
HASH_MURMUR_BYTES(it, h1, c, n, ptr, length);
|
||||
|
||||
end = ptr + length / 4 * 4;
|
||||
switch (n) {
|
||||
case 0:
|
||||
for (; ptr < end; ptr += 4) {
|
||||
k1 = HASH_MURMUR_SAFEREAD(ptr);
|
||||
HASH_MURMUR_BLOCK(h1, k1);
|
||||
}
|
||||
break;
|
||||
|
||||
# define NEXT(N, RIGHT, LEFT) \
|
||||
case N: \
|
||||
for (; ptr < end; ptr += 4) { \
|
||||
k1 = c >> RIGHT; \
|
||||
c = HASH_MURMUR_SAFEREAD(ptr); \
|
||||
k1 |= c << LEFT; \
|
||||
HASH_MURMUR_BLOCK(h1, k1); \
|
||||
} \
|
||||
break
|
||||
NEXT(1, 24, 8);
|
||||
NEXT(2, 16, 16);
|
||||
NEXT(3, 8, 24);
|
||||
#undef NEXT
|
||||
}
|
||||
length -= length/4*4;
|
||||
|
||||
HASH_MURMUR_BYTES(length, h1, c, n, ptr, length);
|
||||
|
||||
*ph1 = h1;
|
||||
*carry = (c & ~0xFF) | n;
|
||||
}
|
||||
#endif
|
||||
|
||||
static GMQCC_FORCEINLINE uint32_t hash_murmur_result(uint32_t hash, uint32_t carry, size_t length) {
|
||||
uint32_t k1;
|
||||
int n = carry & 3;
|
||||
if (GMQCC_LIKELY(n)) {
|
||||
k1 = carry >> (4 - n) * 8;
|
||||
k1 *= HASH_MASK1;
|
||||
k1 *= HASH_MURMUR_MASK1;
|
||||
k1 = HASH_ROTL32(k1, 15);
|
||||
k1 *= HASH_MASK2;
|
||||
k1 *= HASH_MURMUR_MASK2;
|
||||
hash ^= k1;
|
||||
}
|
||||
hash ^= length;
|
||||
hash = hash_mix32(hash);
|
||||
hash = hash_murmur_mix32(hash);
|
||||
|
||||
return hash;
|
||||
}
|
||||
|
||||
static GMQCC_FORCEINLINE GMQCC_USED uint32_t hash_native(const void *GMQCC_RESTRICT key, size_t length) {
|
||||
uint32_t hash = HASH_SEED;
|
||||
static GMQCC_FORCEINLINE uint32_t hash_murmur(const void *GMQCC_RESTRICT key, size_t length) {
|
||||
uint32_t hash = HASH_MURMUR_SEED;
|
||||
uint32_t carry = 0;
|
||||
|
||||
/* Seperate calls for inliner to deal with */
|
||||
hash_native_process(&hash, &carry, key, length);
|
||||
return hash_native_result(hash, carry, length);
|
||||
hash_murmur_process(&hash, &carry, key, length);
|
||||
return hash_murmur_result(hash, carry, length);
|
||||
}
|
||||
|
||||
static uint32_t hash_entry(const void *GMQCC_RESTRICT key, size_t length) {
|
||||
return hash_native(key, length);
|
||||
}
|
||||
|
||||
#define HASH_LEN_ALIGN (sizeof(size_t))
|
||||
#define HASH_LEN_ONES ((size_t)-1/UCHAR_MAX)
|
||||
#define HASH_LEN_HIGHS (HASH_LEN_ONES * (UCHAR_MAX / 2 + 1))
|
||||
#define HASH_LEN_HASZERO(X) (((X)-HASH_LEN_ONES) & ~(X) & HASH_LEN_HIGHS)
|
||||
|
||||
size_t hash(const char *key) {
|
||||
const char *s = key;
|
||||
const char *a = s;
|
||||
const size_t *w;
|
||||
|
||||
/* Align for fast staging */
|
||||
for (; (uintptr_t)s % HASH_LEN_ALIGN; s++) {
|
||||
/* Quick stage if terminated before alignment */
|
||||
for (; (uintptr_t)s % sizeof(size_t); s++)
|
||||
if (!*s)
|
||||
return hash_entry(key, s-a);
|
||||
return hash_murmur((const void *)key, s-a);
|
||||
|
||||
for (w = (const size_t*)s; !((*w-(size_t)-1/UCHAR_MAX) & ~*w & ((size_t)-1/UCHAR_MAX) * (UCHAR_MAX / 2 + 1)); w++);
|
||||
for (s = (const char *)w; *s; s++);
|
||||
|
||||
return hash_murmur((const void *)key, s-a);
|
||||
}
|
||||
|
||||
/*
|
||||
* Efficent staging of words for string length calculation, this is
|
||||
* faster than ifunc resolver of strlen call.
|
||||
*
|
||||
* On a x64 this becomes literally two masks, and a quick skip through
|
||||
* bytes along the string with the following masks:
|
||||
* movabs $0xFEFEFEFEFEFEFEFE,%r8
|
||||
* movabs $0x8080808080808080,%rsi
|
||||
*/
|
||||
for (w = (const void *)s; !HASH_LEN_HASZERO(*w); w++);
|
||||
for (s = (const void *)w; *s; s++);
|
||||
|
||||
return hash_entry(key, s-a);
|
||||
}
|
||||
|
||||
#undef HASH_LEN_HASZERO
|
||||
#undef HASH_LEN_HIGHS
|
||||
#undef HASH_LEN_ONES
|
||||
#undef HASH_LEN_ALIGN
|
||||
#undef HASH_SEED
|
||||
#undef HASH_MASK2
|
||||
#undef HASH_MASK1
|
||||
#undef HASH_ROTL32
|
||||
#undef HASH_NATIVE_BLOCK
|
||||
#undef HASH_NATIVE_BYTES
|
||||
#undef HASH_NATIVE_SAFEREAD
|
||||
|
|
|
|||
Loading…
Reference in a new issue