1 // MIT License
2 3 // Copyright (c) 2019 Ewan Chou
4 5 // Permission is hereby granted, free of charge, to any person obtaining a copy
6 // of this software and associated documentation files (the "Software"), to deal
7 // in the Software without restriction, including without limitation the rights
8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // copies of the Software, and to permit persons to whom the Software is
10 // furnished to do so, subject to the following conditions:
11 12 // The above copyright notice and this permission notice shall be included in all
13 // copies or substantial portions of the Software.
14 15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 // SOFTWARE.
22 23 package z
24 25 import (
26 "unsafe"
27 )
28 29 // NanoTime returns the current time in nanoseconds from a monotonic clock.
30 //
31 //go:linkname NanoTime runtime.nanotime
32 func NanoTime() int64
33 34 // CPUTicks is a faster alternative to NanoTime to measure time duration.
35 //
36 //go:linkname CPUTicks runtime.cputicks
37 func CPUTicks() int64
38 39 type stringStruct struct {
40 str unsafe.Pointer
41 len int
42 }
43 44 //go:noescape
45 //go:linkname memhash runtime.memhash
46 func memhash(p unsafe.Pointer, h, s uintptr) uintptr
47 48 // MemHash is the hash function used by go map, it utilizes available hardware instructions(behaves
49 // as aeshash if aes instruction is available).
50 // NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
51 func MemHash(data []byte) uint64 {
52 ss := (*stringStruct)(unsafe.Pointer(&data))
53 return uint64(memhash(ss.str, 0, uintptr(ss.len)))
54 }
55 56 // MemHashString is the hash function used by go map, it utilizes available hardware instructions
57 // (behaves as aeshash if aes instruction is available).
58 // NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
59 func MemHashString(str string) uint64 {
60 ss := (*stringStruct)(unsafe.Pointer(&str))
61 return uint64(memhash(ss.str, 0, uintptr(ss.len)))
62 }
63 64 // FastRand is a fast thread local random function.
65 //
66 //go:linkname FastRand runtime.fastrand
67 func FastRand() uint32
68 69 //go:linkname memclrNoHeapPointers runtime.memclrNoHeapPointers
70 func memclrNoHeapPointers(p unsafe.Pointer, n uintptr)
71 72 func Memclr(b []byte) {
73 if len(b) == 0 {
74 return
75 }
76 p := unsafe.Pointer(&b[0])
77 memclrNoHeapPointers(p, uintptr(len(b)))
78 }
79