76 lines
2.7 KiB
Go
76 lines
2.7 KiB
Go
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// MIT License
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// Copyright (c) 2019 Ewan Chou
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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package z
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import (
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"unsafe"
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)
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// NanoTime returns the current time in nanoseconds from a monotonic clock.
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//go:linkname NanoTime runtime.nanotime
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func NanoTime() int64
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// CPUTicks is a faster alternative to NanoTime to measure time duration.
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//go:linkname CPUTicks runtime.cputicks
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func CPUTicks() int64
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type stringStruct struct {
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str unsafe.Pointer
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len int
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}
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//go:noescape
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//go:linkname memhash runtime.memhash
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func memhash(p unsafe.Pointer, h, s uintptr) uintptr
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// MemHash is the hash function used by go map, it utilizes available hardware instructions(behaves
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// as aeshash if aes instruction is available).
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// NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
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func MemHash(data []byte) uint64 {
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ss := (*stringStruct)(unsafe.Pointer(&data))
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return uint64(memhash(ss.str, 0, uintptr(ss.len)))
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}
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// MemHashString is the hash function used by go map, it utilizes available hardware instructions
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// (behaves as aeshash if aes instruction is available).
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// NOTE: The hash seed changes for every process. So, this cannot be used as a persistent hash.
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func MemHashString(str string) uint64 {
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ss := (*stringStruct)(unsafe.Pointer(&str))
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return uint64(memhash(ss.str, 0, uintptr(ss.len)))
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}
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// FastRand is a fast thread local random function.
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//go:linkname FastRand runtime.fastrand
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func FastRand() uint32
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//go:linkname memclrNoHeapPointers runtime.memclrNoHeapPointers
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func memclrNoHeapPointers(p unsafe.Pointer, n uintptr)
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func Memclr(b []byte) {
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if len(b) == 0 {
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return
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}
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p := unsafe.Pointer(&b[0])
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memclrNoHeapPointers(p, uintptr(len(b)))
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}
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