mirror of
https://github.com/vlang/v.git
synced 2023-08-10 21:13:21 +03:00
130 lines
3.4 KiB
V
130 lines
3.4 KiB
V
// Copyright (c) 2019-2020 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 wyhash
|
|
|
|
//#flag -I @VROOT/thirdparty/wyhash
|
|
//#include "wyhash.h"
|
|
fn C.wyhash(byteptr, u64, u64) u64
|
|
|
|
|
|
const (
|
|
wyp0 = 0xa0761d6478bd642f
|
|
wyp1 = 0xe7037ed1a0b428db
|
|
wyp2 = 0x8ebc6af09c88c6e3
|
|
wyp3 = 0x589965cc75374cc3
|
|
wyp4 = 0x1d8e4e27c47d124f
|
|
)
|
|
|
|
[inline]
|
|
pub fn wyhash_c(key byteptr, len, seed u64) u64 {
|
|
return C.wyhash(key, len, seed)
|
|
}
|
|
|
|
[inline]
|
|
pub fn sum64_string(key string, seed u64) u64 {
|
|
return wyhash64(key.str, u64(key.len), seed)
|
|
}
|
|
|
|
[inline]
|
|
pub fn sum64(key []byte, seed u64) u64 {
|
|
return wyhash64(key.data, u64(key.len), seed)
|
|
}
|
|
|
|
[inline]
|
|
fn wyhash64(key byteptr, len, seed_ u64) u64 {
|
|
if len == 0 {
|
|
return 0
|
|
}
|
|
mut p := &key[0]
|
|
mut seed := seed_
|
|
mut i := len & 63
|
|
if i < 4 {
|
|
seed = wymum(wyr3(p, i) ^ seed ^ wyp0, seed ^ wyp1)
|
|
}
|
|
else if i <= 8 {
|
|
seed = wymum(wyr4(p) ^ seed ^ wyp0, wyr4(p + i - 4) ^ seed ^ wyp1)
|
|
}
|
|
else if i <= 16 {
|
|
seed = wymum(wyr8(p) ^ seed ^ wyp0, wyr8(p + i - 8) ^ seed ^ wyp1)
|
|
}
|
|
else if i <= 24 {
|
|
seed = wymum(wyr8(p) ^ seed ^ wyp0, wyr8(p + 8) ^ seed ^ wyp1) ^ wymum(wyr8(p + i - 8) ^ seed ^ wyp2, seed ^ wyp3)
|
|
}
|
|
else if i <= 32 {
|
|
seed = wymum(wyr8(p) ^ seed ^ wyp0, wyr8(p + 8) ^ seed ^ wyp1) ^ wymum(wyr8(p + 16) ^ seed ^ wyp2, wyr8(p + i - 8) ^ seed ^ wyp3)
|
|
}
|
|
else {
|
|
seed = wymum(wyr8(p) ^ seed ^ wyp0, wyr8(p + 8) ^ seed ^ wyp1) ^ wymum(wyr8(p + 16) ^ seed ^ wyp2, wyr8(p + 24) ^ seed ^ wyp3) ^ wymum(wyr8(p + i - 32) ^ seed ^ wyp1, wyr8(p + i - 24) ^ seed ^ wyp2) ^ wymum(wyr8(p + i - 16) ^ seed ^ wyp3, wyr8(p + i - 8) ^ seed ^ wyp0)
|
|
}
|
|
if i == len {
|
|
return wymum(seed, len ^ wyp4)
|
|
}
|
|
mut see1 := seed
|
|
mut see2 := seed
|
|
mut see3 := seed
|
|
p = p + i
|
|
for i = len - i; i >= 64; i -= 64 {
|
|
seed = wymum(wyr8(p) ^ seed ^ wyp0, wyr8(p + 8) ^ seed ^ wyp1)
|
|
see1 = wymum(wyr8(p + 16) ^ see1 ^ wyp2, wyr8(p + 24) ^ see1 ^ wyp3)
|
|
see2 = wymum(wyr8(p + 32) ^ see2 ^ wyp1, wyr8(p + 40) ^ see2 ^ wyp2)
|
|
see3 = wymum(wyr8(p + 48) ^ see3 ^ wyp3, wyr8(p + 56) ^ see3 ^ wyp0)
|
|
p = p + 64
|
|
}
|
|
return wymum(seed ^ see1 ^ see2, see3 ^ len ^ wyp4)
|
|
}
|
|
|
|
[inline]
|
|
fn wyrotr(v u64, k u32) u64 {
|
|
return (v>>k) | (v<<(64 - k))
|
|
}
|
|
|
|
[inline]
|
|
fn wymum(a, 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 byteptr, k u64) u64 {
|
|
return (u64(p[0])<<16) | (u64(p[k>>1])<<8) | u64(p[k - 1])
|
|
}
|
|
|
|
[inline]
|
|
fn wyr4(p byteptr) u64 {
|
|
return u32(p[0]) | (u32(p[1])<<u32(8)) | (u32(p[2])<<u32(16)) | (u32(p[3])<<u32(24))
|
|
}
|
|
|
|
[inline]
|
|
fn wyr8(p byteptr) u64 {
|
|
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)
|
|
}
|