github.com/biogo/store@v0.0.0-20201120204734-aad293a2328f/llrb/llrb_example_test.go (about)

     1  // Copyright ©2012 The bíogo Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package llrb_test
     6  
     7  import (
     8  	"fmt"
     9  
    10  	"github.com/biogo/store/llrb"
    11  )
    12  
    13  type (
    14  	Int           int
    15  	IntUpperBound int
    16  )
    17  
    18  func (c Int) Compare(b llrb.Comparable) int {
    19  	switch i := b.(type) {
    20  	case Int:
    21  		return int(c - i)
    22  	case IntUpperBound:
    23  		return int(c) - int(i)
    24  	}
    25  	panic("unknown type")
    26  }
    27  
    28  func (c IntUpperBound) Compare(b llrb.Comparable) int {
    29  	var d int
    30  	switch i := b.(type) {
    31  	case Int:
    32  		d = int(c) - int(i)
    33  	case IntUpperBound:
    34  		d = int(c - i)
    35  	}
    36  	if d == 0 {
    37  		return 1
    38  	}
    39  	return d
    40  }
    41  
    42  func Example() {
    43  	values := []int{0, 1, 2, 3, 4, 2, 3, 5, 5, 65, 32, 3, 23}
    44  
    45  	// Insert using a type that reports equality:
    46  	{
    47  		t := &llrb.Tree{}
    48  		for _, v := range values {
    49  			t.Insert(Int(v)) // Insert with replacement.
    50  		}
    51  
    52  		results := []int(nil)
    53  		// More efficiently retrieved using Get(Int(3))...
    54  		t.DoMatching(func(c llrb.Comparable) (done bool) {
    55  			results = append(results, int(c.(Int)))
    56  			return
    57  		}, Int(3))
    58  
    59  		fmt.Println("With replacement:   ", results)
    60  	}
    61  
    62  	// Insert using a type that does not report equality:
    63  	{
    64  		t := &llrb.Tree{}
    65  		for _, v := range values {
    66  			t.Insert(IntUpperBound(v)) // Insert without replacement.
    67  		}
    68  
    69  		results := []int(nil)
    70  		t.DoMatching(func(c llrb.Comparable) (done bool) {
    71  			results = append(results, int(c.(IntUpperBound)))
    72  			return
    73  		}, Int(3))
    74  
    75  		fmt.Println("Without replacement:", results)
    76  	}
    77  
    78  	// Output:
    79  	// With replacement:    [3]
    80  	// Without replacement: [3 3 3]
    81  }