github.com/cloudwego/dynamicgo@v0.2.6-0.20240519101509-707f41b6b834/internal/caching/hashing.go (about) 1 /* 2 * Copyright 2023 CloudWeGo Authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package caching 18 19 import ( 20 "unsafe" 21 22 "github.com/cloudwego/dynamicgo/internal/rt" 23 ) 24 25 var ( 26 V_strhash = rt.UnpackEface(strhash) 27 S_strhash = *(*uintptr)(V_strhash.Value) 28 byteTypeSize = unsafe.Sizeof(byte(0)) 29 ) 30 31 //go:noescape 32 //go:linkname strhash runtime.strhash 33 func strhash(_ unsafe.Pointer, _ uintptr) uintptr 34 35 func StrHash(s string) uint64 { 36 if v := strhash(unsafe.Pointer(&s), 0); v == 0 { 37 return 1 38 } else { 39 return uint64(v) 40 } 41 } 42 43 func DJBHash32(k string) uint32 { 44 var hash uint32 = 5381 45 var ks = *(*unsafe.Pointer)(unsafe.Pointer(&k)) 46 for i := 0; i < len(k); i++ { 47 c := *(*byte)(rt.IndexPtr(ks, byteTypeSize, i)) 48 hash = ((hash << 5) + hash + uint32(c)) 49 } 50 return hash 51 } 52 53 func DJBHash64(k string) uint64 { 54 var hash uint64 = 5381 55 var ks = *(*unsafe.Pointer)(unsafe.Pointer(&k)) 56 for i := 0; i < len(k); i++ { 57 c := *(*byte)(rt.IndexPtr(ks, byteTypeSize, i)) 58 hash = ((hash << 5) + hash + uint64(c)) 59 } 60 return hash 61 }