binarytree/comparable.go at master · tomdionysus/binarytree · GitHub

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package binarytree

import(
  "bytes"
)
// Comparable is an interface for comparable types. All keys used in this implementation of
// a binary tree must implement this interface.
//
// Helper types are supplied for some primitives, please see `IntKey`, [StringKey] and [ByteSliceKey]
type Comparable interface {
  LessThan(Comparable) bool
  EqualTo(Comparable) bool
  GreaterThan(Comparable) bool
  ValueOf() interface{}
}

// IntKey is a type of base type int that implements the Comparable interface.
type IntKey int

// Return true if this key is less than the supplied IntKey.
func (me IntKey) LessThan(other Comparable) bool {
  return me < other.(IntKey)
}

// Return true if this key is equal to the supplied IntKey.
func (me IntKey) EqualTo(other Comparable) bool {
  return me == other.(IntKey)
}

// Return true if this key is greater than the supplied IntKey.
func (me IntKey) GreaterThan(other Comparable) bool {
  return me > other.(IntKey)
}

// Return the int value as an interface
func (me IntKey) ValueOf() interface{} {
  return int(me)
}

// StringKey is a type of base type String that implements the Comparable interface.
type StringKey string

// Return true if this key is less than the supplied StringKey.
func (me StringKey) LessThan(other Comparable) bool {
  return me < other.(StringKey)
}

// Return true if this key is equal to the supplied StringKey.
func (me StringKey) EqualTo(other Comparable) bool {
  return me == other.(StringKey)
}

// Return true if this key is greater than the supplied StringKey.
func (me StringKey) GreaterThan(other Comparable) bool {
  return me > other.(StringKey)
}

// Return the string value as an interface
func (me StringKey) ValueOf() interface{} {
  return string(me)
}

// StringKey is a type of base type String that implements the Comparable interface.
type ByteSliceKey []byte

// Return true if this key is less than the supplied ByteSliceKey.
func (me ByteSliceKey) LessThan(other Comparable) bool {
  if len(me) > len(other.(ByteSliceKey)) { return false }
  if len(me) < len(other.(ByteSliceKey)) { return true }

  return bytes.Compare(me.ValueOf().([]byte), other.ValueOf().([]byte)) < 0
}

// Return true if this key is equal to the supplied ByteSliceKey.
func (me ByteSliceKey) EqualTo(other Comparable) bool {
  if len(me) != len(other.(ByteSliceKey)) { return false }
  return bytes.Compare(me.ValueOf().([]byte), other.ValueOf().([]byte)) == 0
}

// Return true if this key is greater than the supplied ByteSliceKey.
func (me ByteSliceKey) GreaterThan(other Comparable) bool {
  if len(me) < len(other.(ByteSliceKey)) { return false }
  if len(me) > len(other.(ByteSliceKey)) { return true }

  return bytes.Compare(me.ValueOf().([]byte), other.ValueOf().([]byte)) > 0
}

// Return the []byte value as an interface
func (me ByteSliceKey) ValueOf() interface{} {
  return []byte(me)
}