github.com/bhojpur/cache@v0.0.4/pkg/hack/hack.go (about)

     1  package hack
     2  
     3  // Copyright (c) 2018 Bhojpur Consulting Private Limited, India. All rights reserved.
     4  
     5  // Permission is hereby granted, free of charge, to any person obtaining a copy
     6  // of this software and associated documentation files (the "Software"), to deal
     7  // in the Software without restriction, including without limitation the rights
     8  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     9  // copies of the Software, and to permit persons to whom the Software is
    10  // furnished to do so, subject to the following conditions:
    11  
    12  // The above copyright notice and this permission notice shall be included in
    13  // all copies or substantial portions of the Software.
    14  
    15  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    16  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    17  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    18  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    19  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    20  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    21  // THE SOFTWARE.
    22  
    23  import (
    24  	"reflect"
    25  	"unsafe"
    26  )
    27  
    28  // String force casts a []byte to a string.
    29  // USE AT YOUR OWN RISK
    30  func String(b []byte) (s string) {
    31  	if len(b) == 0 {
    32  		return ""
    33  	}
    34  	return *(*string)(unsafe.Pointer(&b))
    35  }
    36  
    37  // StringPointer returns &s[0], which is not allowed in go
    38  func StringPointer(s string) unsafe.Pointer {
    39  	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
    40  	return unsafe.Pointer(pstring.Data)
    41  }
    42  
    43  // StringBytes returns the underlying bytes for a string. Modifying this byte slice
    44  // will lead to undefined behavior.
    45  func StringBytes(s string) []byte {
    46  	var b []byte
    47  	hdr := (*reflect.SliceHeader)(unsafe.Pointer(&b))
    48  	hdr.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
    49  	hdr.Cap = len(s)
    50  	hdr.Len = len(s)
    51  	return b
    52  }
    53  
    54  // StringClone returns a newly allocated copy of the string that doesn't share
    55  // its underlying memory storage.
    56  func StringClone(s string) string {
    57  	b := make([]byte, len(s))
    58  	copy(b, s)
    59  	return *(*string)(unsafe.Pointer(&b))
    60  }