github.com/team-ide/go-dialect@v1.9.20/vitess/hack/hack.go (about)

     1  /*
     2  Copyright 2019 The Vitess 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 hack gives you some efficient functionality at the cost of
    18  // breaking some Go rules.
    19  package hack
    20  
    21  import (
    22  	"reflect"
    23  	"unsafe"
    24  )
    25  
    26  // String force casts a []byte to a string.
    27  // USE AT YOUR OWN RISK
    28  func String(b []byte) (s string) {
    29  	if len(b) == 0 {
    30  		return ""
    31  	}
    32  	return *(*string)(unsafe.Pointer(&b))
    33  }
    34  
    35  // StringPointer returns &s[0], which is not allowed in go
    36  func StringPointer(s string) unsafe.Pointer {
    37  	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
    38  	return unsafe.Pointer(pstring.Data)
    39  }
    40  
    41  // StringBytes returns the underlying bytes for a string. Modifying this byte slice
    42  // will lead to undefined behavior.
    43  func StringBytes(s string) []byte {
    44  	var b []byte
    45  	hdr := (*reflect.SliceHeader)(unsafe.Pointer(&b))
    46  	hdr.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
    47  	hdr.Cap = len(s)
    48  	hdr.Len = len(s)
    49  	return b
    50  }
    51  
    52  // StringClone returns a newly allocated copy of the string that doesn't share
    53  // its underlying memory storage.
    54  func StringClone(s string) string {
    55  	b := make([]byte, len(s))
    56  	copy(b, s)
    57  	return *(*string)(unsafe.Pointer(&b))
    58  }