interfaces.go

// Copyright 2009 The Go Authors.
// Copyright 2015 Randall Farmer.
// All rights reserved.

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package sorts does parallel radix sorts of data by (u)int64, string, or
// []byte keys, and parallel quicksort.  See the sorts/sortutil package for
// shortcuts for common slice types and help sorting floats.
package sorts

import "sort" // for Interface

// Uint64Interface represents a collection that can be sorted by a uint64
// key.
type Uint64Interface interface {
	sort.Interface
	// Key provides a uint64 key for element i.
	Key(i int) uint64
}

// Uint128Interface represents a collection that can be sorted by a uint128
// key.
type Uint128Interface interface {
	sort.Interface
	// Key provides a uint128 key for element i, in the form of 2 uint64s
	// containing the high and low bits, respectively.
	Key(i int) (uint64, uint64)
}

// Int64Interface represents a collection that can be sorted by an int64
// key.
type Int64Interface interface {
	sort.Interface
	// Key provides an int64 key for element i.
	Key(i int) int64
}

// StringInterface represents a collection that can be sorted by a string
// key.
type StringInterface interface {
	sort.Interface
	// Key provides the string key for element i.
	Key(i int) string
}

// BytesInterface represents a collection that can be sorted by a []byte
// key.
type BytesInterface interface {
	sort.Interface
	// Key provides the []byte key for element i.
	Key(i int) []byte
}

// Flip reverses the order of items in a sort.Interface.
func Flip(data sort.Interface) {
	a, b := 0, data.Len()-1
	for b > a {
		data.Swap(a, b)
		a++
		b--
	}
}