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small optimization when streaming small quantities

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described in #1011 by @aleksazr as point 2:
this optimization avoids copying accumulators
when there is not enough data to compute them anyway.
Seems effective on MSVC.

Such a scenario implies streaming, and receiving very little data per invocation.
This commit is contained in:
Yann Collet
2025-06-19 15:29:10 -07:00
parent 83a85f6423
commit 4f43b71778
1 changed files with 10 additions and 9 deletions
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19
xxhash.h
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@@ -6715,6 +6715,16 @@ XXH3_update(XXH3_state_t* XXH_RESTRICT const state,
}
XXH_ASSERT(state != NULL);
state->totalLen += len;
/* small input : just fill in tmp buffer */
XXH_ASSERT(state->bufferedSize <= XXH3_INTERNALBUFFER_SIZE);
if (len <= XXH3_INTERNALBUFFER_SIZE - state->bufferedSize) {
XXH_memcpy(state->buffer + state->bufferedSize, input, len);
state->bufferedSize += (XXH32_hash_t)len;
return XXH_OK;
}
{ const xxh_u8* const bEnd = input + len;
const unsigned char* const secret = (state->extSecret == NULL) ? state->customSecret : state->extSecret;
#if defined(XXH3_STREAM_USE_STACK) && XXH3_STREAM_USE_STACK >= 1
@@ -6727,15 +6737,6 @@ XXH3_update(XXH3_state_t* XXH_RESTRICT const state,
#else
xxh_u64* XXH_RESTRICT const acc = state->acc;
#endif
state->totalLen += len;
XXH_ASSERT(state->bufferedSize <= XXH3_INTERNALBUFFER_SIZE);
/* small input : just fill in tmp buffer */
if (len <= XXH3_INTERNALBUFFER_SIZE - state->bufferedSize) {
XXH_memcpy(state->buffer + state->bufferedSize, input, len);
state->bufferedSize += (XXH32_hash_t)len;
return XXH_OK;
}
/* total input is now > XXH3_INTERNALBUFFER_SIZE */
#define XXH3_INTERNALBUFFER_STRIPES (XXH3_INTERNALBUFFER_SIZE / XXH_STRIPE_LEN)