mirror of https://github.com/golang/go.git
66 lines
1.9 KiB
Go
66 lines
1.9 KiB
Go
// Copyright 2023 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
//go:build !purego
|
|
|
|
package maphash
|
|
|
|
import (
|
|
"internal/abi"
|
|
"internal/unsafeheader"
|
|
"unsafe"
|
|
)
|
|
|
|
//go:linkname runtime_rand runtime.rand
|
|
func runtime_rand() uint64
|
|
|
|
//go:linkname runtime_memhash runtime.memhash
|
|
//go:noescape
|
|
func runtime_memhash(p unsafe.Pointer, seed, s uintptr) uintptr
|
|
|
|
func rthash(buf []byte, seed uint64) uint64 {
|
|
if len(buf) == 0 {
|
|
return seed
|
|
}
|
|
len := len(buf)
|
|
// The runtime hasher only works on uintptr. For 64-bit
|
|
// architectures, we use the hasher directly. Otherwise,
|
|
// we use two parallel hashers on the lower and upper 32 bits.
|
|
if unsafe.Sizeof(uintptr(0)) == 8 {
|
|
return uint64(runtime_memhash(unsafe.Pointer(&buf[0]), uintptr(seed), uintptr(len)))
|
|
}
|
|
lo := runtime_memhash(unsafe.Pointer(&buf[0]), uintptr(seed), uintptr(len))
|
|
hi := runtime_memhash(unsafe.Pointer(&buf[0]), uintptr(seed>>32), uintptr(len))
|
|
return uint64(hi)<<32 | uint64(lo)
|
|
}
|
|
|
|
func rthashString(s string, state uint64) uint64 {
|
|
buf := unsafe.Slice(unsafe.StringData(s), len(s))
|
|
return rthash(buf, state)
|
|
}
|
|
|
|
func randUint64() uint64 {
|
|
return runtime_rand()
|
|
}
|
|
|
|
func comparableF[T comparable](seed uint64, v T, t *abi.Type) uint64 {
|
|
k := t.Kind()
|
|
len := t.Size()
|
|
ptr := unsafe.Pointer(&v)
|
|
switch k {
|
|
case abi.Slice:
|
|
len = uintptr(((*unsafeheader.Slice)(unsafe.Pointer(&v))).Len) * t.Elem().Size()
|
|
ptr = ((*unsafeheader.Slice)(unsafe.Pointer(&v))).Data
|
|
case abi.String:
|
|
len = uintptr(((*unsafeheader.String)(unsafe.Pointer(&v))).Len)
|
|
ptr = ((*unsafeheader.String)(unsafe.Pointer(&v))).Data
|
|
}
|
|
if unsafe.Sizeof(uintptr(0)) == 8 {
|
|
return uint64(runtime_memhash(ptr, uintptr(seed), len))
|
|
}
|
|
lo := runtime_memhash(ptr, uintptr(seed), len)
|
|
hi := runtime_memhash(ptr, uintptr(seed>>32), len)
|
|
return uint64(hi)<<32 | uint64(lo)
|
|
}
|