FEX-Emu/xxHash
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do not regenerate secret from seed

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when state was already used with the same `seed` previously.
This skips secret generation when `seed` remains constant.

Also : improves streaming speed on small data
thanks to lighter memset() during reset().
This commit is contained in:
Yann Collet 2020-07-10 22:11:45 -07:00
parent 289813fab9
commit 18f0991cef
3 changed files with 29 additions and 15 deletions
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31
xxh3.h
View File

@ -1902,7 +1902,10 @@ static void XXH_alignedFree(void* p)
}
XXH_PUBLIC_API XXH3_state_t* XXH3_createState(void)
{
return (XXH3_state_t*)XXH_alignedMalloc(sizeof(XXH3_state_t), 64);
XXH3_state_t* const state = XXH_alignedMalloc(sizeof(XXH3_state_t), 64);
if (state==NULL) return NULL;
XXH3_INITSTATE(state);
return state;
}
XXH_PUBLIC_API XXH_errorcode XXH3_freeState(XXH3_state_t* statePtr)
@ -1920,10 +1923,11 @@ XXH3_copyState(XXH3_state_t* dst_state, const XXH3_state_t* src_state)
static void
XXH3_64bits_reset_internal(XXH3_state_t* statePtr,
XXH64_hash_t seed,
const xxh_u8* secret, size_t secretSize)
const void* secret, size_t secretSize)
{
size_t const initStart = offsetof(XXH3_state_t, bufferedSize);
XXH_ASSERT(statePtr != NULL);
memset(statePtr, 0, sizeof(*statePtr));
memset((char*)statePtr + initStart, 0, sizeof(*statePtr) - initStart);
statePtr->acc[0] = XXH_PRIME32_3;
statePtr->acc[1] = XXH_PRIME64_1;
statePtr->acc[2] = XXH_PRIME64_2;
@ -1933,8 +1937,7 @@ XXH3_64bits_reset_internal(XXH3_state_t* statePtr,
statePtr->acc[6] = XXH_PRIME64_5;
statePtr->acc[7] = XXH_PRIME32_1;
statePtr->seed = seed;
XXH_ASSERT(secret != NULL);
statePtr->extSecret = secret;
statePtr->extSecret = (const unsigned char*)secret;
XXH_ASSERT(secretSize >= XXH3_SECRET_SIZE_MIN);
statePtr->secretLimit = secretSize - XXH_STRIPE_LEN;
statePtr->nbStripesPerBlock = statePtr->secretLimit / XXH_SECRET_CONSUME_RATE;
@ -1952,7 +1955,7 @@ XXH_PUBLIC_API XXH_errorcode
XXH3_64bits_reset_withSecret(XXH3_state_t* statePtr, const void* secret, size_t secretSize)
{
if (statePtr == NULL) return XXH_ERROR;
XXH3_64bits_reset_internal(statePtr, 0, (const xxh_u8*)secret, secretSize);
XXH3_64bits_reset_internal(statePtr, 0, secret, secretSize);
if (secret == NULL) return XXH_ERROR;
if (secretSize < XXH3_SECRET_SIZE_MIN) return XXH_ERROR;
return XXH_OK;
@ -1962,9 +1965,9 @@ XXH_PUBLIC_API XXH_errorcode
XXH3_64bits_reset_withSeed(XXH3_state_t* statePtr, XXH64_hash_t seed)
{
if (statePtr == NULL) return XXH_ERROR;
XXH3_64bits_reset_internal(statePtr, seed, XXH3_kSecret, XXH_SECRET_DEFAULT_SIZE);
XXH3_initCustomSecret(statePtr->customSecret, seed);
statePtr->extSecret = NULL;
if (seed==0) return XXH3_64bits_reset(statePtr);
if (seed != statePtr->seed) XXH3_initCustomSecret(statePtr->customSecret, seed);
XXH3_64bits_reset_internal(statePtr, seed, NULL, XXH_SECRET_DEFAULT_SIZE);
return XXH_OK;
}
@ -2581,7 +2584,7 @@ XXH128(const void* input, size_t len, XXH64_hash_t seed)
static void
XXH3_128bits_reset_internal(XXH3_state_t* statePtr,
XXH64_hash_t seed,
const xxh_u8* secret, size_t secretSize)
const void* secret, size_t secretSize)
{
XXH3_64bits_reset_internal(statePtr, seed, secret, secretSize);
}
@ -2598,7 +2601,7 @@ XXH_PUBLIC_API XXH_errorcode
XXH3_128bits_reset_withSecret(XXH3_state_t* statePtr, const void* secret, size_t secretSize)
{
if (statePtr == NULL) return XXH_ERROR;
XXH3_128bits_reset_internal(statePtr, 0, (const xxh_u8*)secret, secretSize);
XXH3_128bits_reset_internal(statePtr, 0, secret, secretSize);
if (secret == NULL) return XXH_ERROR;
if (secretSize < XXH3_SECRET_SIZE_MIN) return XXH_ERROR;
return XXH_OK;
@ -2608,9 +2611,9 @@ XXH_PUBLIC_API XXH_errorcode
XXH3_128bits_reset_withSeed(XXH3_state_t* statePtr, XXH64_hash_t seed)
{
if (statePtr == NULL) return XXH_ERROR;
XXH3_128bits_reset_internal(statePtr, seed, XXH3_kSecret, XXH_SECRET_DEFAULT_SIZE);
XXH3_initCustomSecret(statePtr->customSecret, seed);
statePtr->extSecret = NULL;
if (seed==0) return XXH3_128bits_reset(statePtr);
if (seed != statePtr->seed) XXH3_initCustomSecret(statePtr->customSecret, seed);
XXH3_128bits_reset_internal(statePtr, seed, NULL, XXH_SECRET_DEFAULT_SIZE);
return XXH_OK;
}

10
xxhash.h
View File

@ -572,6 +572,16 @@ struct XXH3_state_s {
#undef XXH_ALIGN_MEMBER
/* When the XXH3_state_t structure is merely emplaced on stack,
* it should be initialized with XXH3_INITSTATE() or a memset()
* in case its first reset uses XXH3_NNbits_reset_withSeed().
* This init can be omitted if the first reset uses default or _withSecret mode.
* This operation isn't necessary when the state is created with XXH3_createState().
* Note that this doesn't prepare the state for a streaming operation,
* it's still necessary to use XXH3_NNbits_reset*() afterwards.
*/
#define XXH3_INITSTATE(XXH3_state_ptr) { (XXH3_state_ptr)->seed = 0; }
/*
* Streaming requires state maintenance.
* This operation costs memory and CPU.

3
xxhsum.c
View File

@ -660,6 +660,7 @@ static U32 localXXH3_stream(const void* buffer, size_t bufferSize, U32 seed)
static U32 localXXH3_stream_seeded(const void* buffer, size_t bufferSize, U32 seed)
{
XXH3_state_t state;
XXH3_INITSTATE(&state);
XXH3_64bits_reset_withSeed(&state, (XXH64_hash_t)seed);
XXH3_64bits_update(&state, buffer, bufferSize);
return (U32)XXH3_64bits_digest(&state);
@ -675,7 +676,7 @@ static U32 localXXH128_stream(const void* buffer, size_t bufferSize, U32 seed)
static U32 localXXH128_stream_seeded(const void* buffer, size_t bufferSize, U32 seed)
{
XXH3_state_t state;
(void)seed;
XXH3_INITSTATE(&state);
XXH3_128bits_reset_withSeed(&state, (XXH64_hash_t)seed);
XXH3_128bits_update(&state, buffer, bufferSize);
return (U32)(XXH3_128bits_digest(&state).low64);