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authorIndrajith K L2022-12-03 17:00:20 +0530
committerIndrajith K L2022-12-03 17:00:20 +0530
commitf5c4671bfbad96bf346bd7e9a21fc4317b4959df (patch)
tree2764fc62da58f2ba8da7ed341643fc359873142f /v_windows/v/old/vlib/hash/wyhash.v
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Adds most of the toolsHEADmaster
Diffstat (limited to 'v_windows/v/old/vlib/hash/wyhash.v')
-rw-r--r--v_windows/v/old/vlib/hash/wyhash.v82
1 files changed, 82 insertions, 0 deletions
diff --git a/v_windows/v/old/vlib/hash/wyhash.v b/v_windows/v/old/vlib/hash/wyhash.v
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+++ b/v_windows/v/old/vlib/hash/wyhash.v
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+// Copyright (c) 2019-2021 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+//
+// this is an implementation of wyhash v4
+// from https://github.com/wangyi-fudan/wyhash
+//
+// TODO: use u128 once implemented
+// currently the C version performs slightly better
+// because it uses 128 bit int when available and
+// branch prediction hints. the C version will be
+// removed once the perfomance is matched.
+// you can test performance by running:
+// `v run cmd/tools/bench/wyhash.v`
+// try running with and without the `-prod` flag
+module hash
+
+const (
+ wyp0 = u64(0xa0761d6478bd642f)
+ wyp1 = u64(0xe7037ed1a0b428db)
+ wyp2 = u64(0x8ebc6af09c88c6e3)
+ wyp3 = u64(0x589965cc75374cc3)
+ wyp4 = u64(0x1d8e4e27c47d124f)
+)
+
+[inline]
+pub fn sum64_string(key string, seed u64) u64 {
+ return wyhash_c(key.str, u64(key.len), seed)
+}
+
+[inline]
+pub fn sum64(key []byte, seed u64) u64 {
+ return wyhash_c(&byte(key.data), u64(key.len), seed)
+}
+
+[inline]
+fn wyrotr(v u64, k u32) u64 {
+ return (v >> k) | (v << (64 - k))
+}
+
+[inline]
+pub fn wymum(a u64, b u64) u64 {
+ /*
+ mut r := u128(a)
+ r = r*b
+ return (r>>64)^r
+ */
+ mask32 := u32(4294967295)
+ x0 := a & mask32
+ x1 := a >> 32
+ y0 := b & mask32
+ y1 := b >> 32
+ w0 := x0 * y0
+ t := x1 * y0 + (w0 >> 32)
+ mut w1 := t & mask32
+ w2 := t >> 32
+ w1 += x0 * y1
+ hi := x1 * y1 + w2 + (w1 >> 32)
+ lo := a * b
+ return hi ^ lo
+}
+
+[inline]
+fn wyr3(p &byte, k u64) u64 {
+ unsafe {
+ return (u64(p[0]) << 16) | (u64(p[k >> 1]) << 8) | u64(p[k - 1])
+ }
+}
+
+[inline]
+fn wyr4(p &byte) u64 {
+ unsafe {
+ return u32(p[0]) | (u32(p[1]) << u32(8)) | (u32(p[2]) << u32(16)) | (u32(p[3]) << u32(24))
+ }
+}
+
+[inline]
+fn wyr8(p &byte) u64 {
+ unsafe {
+ return u64(p[0]) | (u64(p[1]) << 8) | (u64(p[2]) << 16) | (u64(p[3]) << 24) | (u64(p[4]) << 32) | (u64(p[5]) << 40) | (u64(p[6]) << 48) | (u64(p[7]) << 56)
+ }
+}