From 91b5f65fd5d8d8d5aabf3247effec4ec6b2a8a63 Mon Sep 17 00:00:00 2001
From: Andrea Shepard <andrea@special-circumstanc.es>
Date: Sun, 12 Jan 2020 04:20:24 +0000
Subject: [PATCH] Unroll djbhash for ~25% speedup
---
src/datastructures.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/src/datastructures.c b/src/datastructures.c
index ba012b76..6971e0e0 100644
--- a/src/datastructures.c
+++ b/src/datastructures.c
@@ -437,11 +437,26 @@ HHashValue h_hash_ptr(const void *p) {
}
uint32_t h_djbhash(const uint8_t *buf, size_t len) {
- uint32_t hash = 5381;
+ uint32_t h = 5381;
+
+ while (len >= 16) {
+ h = h * 33 + buf[0]; h = h * 33 + buf[1];
+ h = h * 33 + buf[2]; h = h * 33 + buf[3];
+ h = h * 33 + buf[4]; h = h * 33 + buf[5];
+ h = h * 33 + buf[6]; h = h * 33 + buf[7];
+ h = h * 33 + buf[8]; h = h * 33 + buf[9];
+ h = h * 33 + buf[10]; h = h * 33 + buf[11];
+ h = h * 33 + buf[12]; h = h * 33 + buf[13];
+ h = h * 33 + buf[14]; h = h * 33 + buf[15];
+ len -= 16;
+ buf += 16;
+ }
+
while (len--) {
- hash = hash * 33 + *buf++;
+ h = h * 33 + *buf++;
}
- return hash;
+
+ return h;
}
void h_symbol_put(HParseState *state, const char* key, void *value) {
--
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