github.com/mitghi/x@v0.0.0-20191206171256-71e86edf750d/pointers/tagged_test.go (about)

     1  /* MIT License
     2  *
     3  * Copyright (c) 2018 Mike Taghavi <mitghi[at]gmail.com>
     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  * The above copyright notice and this permission notice shall be included in all
    12  * copies or substantial portions of the Software.
    13  *
    14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    19  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    20  * SOFTWARE.
    21   */
    22  
    23  package pointers
    24  
    25  import (
    26  	"fmt"
    27  	"testing"
    28  	"unsafe"
    29  )
    30  
    31  func TestTag(t *testing.T) {
    32  	const sval = 8
    33  	var (
    34  		s    *Sample = &Sample{value: sval}
    35  		sptr unsafe.Pointer
    36  		tag  uint
    37  		err  error
    38  	)
    39  	sptr, err = TaggedPointer(unsafe.Pointer(s), 1)
    40  	if err != nil {
    41  		t.Fatal("assertion failed, expected==nil.")
    42  	}
    43  	s = (*Sample)(sptr)
    44  	tag = GetTag(sptr)
    45  	fmt.Println("Tag: ", tag)
    46  	sptr = Untag(unsafe.Pointer(s))
    47  	s = (*Sample)(sptr)
    48  	if s == nil || s.value != sval {
    49  		t.Fatal("assertion failed, expected s.value==sval.")
    50  	}
    51  	tag = GetTag(sptr)
    52  	if tag != 0 {
    53  		t.Fatal("assertion failed, expected tag==0.")
    54  	}
    55  }