github.com/noisysockets/netstack@v0.6.0/pkg/gohacks/string_go120_unsafe.go (about) 1 // Copyright 2023 The gVisor Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 //go:build go1.20 16 17 package gohacks 18 19 import ( 20 "unsafe" 21 ) 22 23 // ImmutableBytesFromString is equivalent to []byte(s), except that it uses the 24 // same memory backing s instead of making a heap-allocated copy. This is only 25 // valid if the returned slice is never mutated. 26 func ImmutableBytesFromString(s string) []byte { 27 b := unsafe.StringData(s) 28 return unsafe.Slice(b, len(s)) 29 } 30 31 // StringFromImmutableBytes is equivalent to string(bs), except that it uses 32 // the same memory backing bs instead of making a heap-allocated copy. This is 33 // only valid if bs is never mutated after StringFromImmutableBytes returns. 34 func StringFromImmutableBytes(bs []byte) string { 35 if len(bs) == 0 { 36 return "" 37 } 38 return unsafe.String(&bs[0], len(bs)) 39 }