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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package sort
import (
"fmt"
"rand"
"strconv"
"testing"
)
var ints = [...]int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586}
var float64s = [...]float64{74.3, 59.0, 238.2, -784.0, 2.3, 9845.768, -959.7485, 905, 7.8, 7.8}
var strings = [...]string{"", "Hello", "foo", "bar", "foo", "f00", "%*&^*&^&", "***"}
func TestSortIntArray(t *testing.T) {
data := ints
a := IntArray(data[0:])
Sort(a)
if !IsSorted(a) {
t.Errorf("sorted %v", ints)
t.Errorf(" got %v", data)
}
}
func TestSortFloat64Array(t *testing.T) {
data := float64s
a := Float64Array(data[0:])
Sort(a)
if !IsSorted(a) {
t.Errorf("sorted %v", float64s)
t.Errorf(" got %v", data)
}
}
func TestSortStringArray(t *testing.T) {
data := strings
a := StringArray(data[0:])
Sort(a)
if !IsSorted(a) {
t.Errorf("sorted %v", strings)
t.Errorf(" got %v", data)
}
}
func TestSortInts(t *testing.T) {
data := ints
SortInts(data[0:])
if !IntsAreSorted(data[0:]) {
t.Errorf("sorted %v", ints)
t.Errorf(" got %v", data)
}
}
func TestSortFloat64s(t *testing.T) {
data := float64s
SortFloat64s(data[0:])
if !Float64sAreSorted(data[0:]) {
t.Errorf("sorted %v", float64s)
t.Errorf(" got %v", data)
}
}
func TestSortStrings(t *testing.T) {
data := strings
SortStrings(data[0:])
if !StringsAreSorted(data[0:]) {
t.Errorf("sorted %v", strings)
t.Errorf(" got %v", data)
}
}
func TestSortLarge_Random(t *testing.T) {
data := make([]int, 1000000)
for i := 0; i < len(data); i++ {
data[i] = rand.Intn(100)
}
if IntsAreSorted(data) {
t.Fatalf("terrible rand.rand")
}
SortInts(data)
if !IntsAreSorted(data) {
t.Errorf("sort didn't sort - 1M ints")
}
}
func BenchmarkSortString1K(b *testing.B) {
b.StopTimer()
for i := 0; i < b.N; i++ {
data := make([]string, 1<<10)
for i := 0; i < len(data); i++ {
data[i] = strconv.Itoa(i ^ 0x2cc)
}
b.StartTimer()
SortStrings(data)
b.StopTimer()
}
}
func BenchmarkSortInt1K(b *testing.B) {
b.StopTimer()
for i := 0; i < b.N; i++ {
data := make([]int, 1<<10)
for i := 0; i < len(data); i++ {
data[i] = i ^ 0x2cc
}
b.StartTimer()
SortInts(data)
b.StopTimer()
}
}
func BenchmarkSortInt64K(b *testing.B) {
b.StopTimer()
for i := 0; i < b.N; i++ {
data := make([]int, 1<<16)
for i := 0; i < len(data); i++ {
data[i] = i ^ 0xcccc
}
b.StartTimer()
SortInts(data)
b.StopTimer()
}
}
const (
_Sawtooth = iota
_Rand
_Stagger
_Plateau
_Shuffle
_NDist
)
const (
_Copy = iota
_Reverse
_ReverseFirstHalf
_ReverseSecondHalf
_Sorted
_Dither
_NMode
)
type testingData struct {
desc string
t *testing.T
data []int
maxswap int // number of swaps allowed
nswap int
}
func (d *testingData) Len() int { return len(d.data) }
func (d *testingData) Less(i, j int) bool { return d.data[i] < d.data[j] }
func (d *testingData) Swap(i, j int) {
if d.nswap >= d.maxswap {
d.t.Errorf("%s: used %d swaps sorting array of %d", d.desc, d.nswap, len(d.data))
d.t.FailNow()
}
d.nswap++
d.data[i], d.data[j] = d.data[j], d.data[i]
}
func lg(n int) int {
i := 0
for 1<<uint(i) < n {
i++
}
return i
}
func TestBentleyMcIlroy(t *testing.T) {
sizes := []int{100, 1023, 1024, 1025}
dists := []string{"sawtooth", "rand", "stagger", "plateau", "shuffle"}
modes := []string{"copy", "reverse", "reverse1", "reverse2", "sort", "dither"}
var tmp1, tmp2 [1025]int
for ni := 0; ni < len(sizes); ni++ {
n := sizes[ni]
for m := 1; m < 2*n; m *= 2 {
for dist := 0; dist < _NDist; dist++ {
j := 0
k := 1
data := tmp1[0:n]
for i := 0; i < n; i++ {
switch dist {
case _Sawtooth:
data[i] = i % m
case _Rand:
data[i] = rand.Intn(m)
case _Stagger:
data[i] = (i*m + i) % n
case _Plateau:
data[i] = min(i, m)
case _Shuffle:
if rand.Intn(m) != 0 {
j += 2
data[i] = j
} else {
k += 2
data[i] = k
}
}
}
mdata := tmp2[0:n]
for mode := 0; mode < _NMode; mode++ {
switch mode {
case _Copy:
for i := 0; i < n; i++ {
mdata[i] = data[i]
}
case _Reverse:
for i := 0; i < n; i++ {
mdata[i] = data[n-i-1]
}
case _ReverseFirstHalf:
for i := 0; i < n/2; i++ {
mdata[i] = data[n/2-i-1]
}
for i := n / 2; i < n; i++ {
mdata[i] = data[i]
}
case _ReverseSecondHalf:
for i := 0; i < n/2; i++ {
mdata[i] = data[i]
}
for i := n / 2; i < n; i++ {
mdata[i] = data[n-(i-n/2)-1]
}
case _Sorted:
for i := 0; i < n; i++ {
mdata[i] = data[i]
}
// SortInts is known to be correct
// because mode Sort runs after mode _Copy.
SortInts(mdata)
case _Dither:
for i := 0; i < n; i++ {
mdata[i] = data[i] + i%5
}
}
desc := fmt.Sprintf("n=%d m=%d dist=%s mode=%s", n, m, dists[dist], modes[mode])
d := &testingData{desc, t, mdata[0:n], n * lg(n) * 12 / 10, 0}
Sort(d)
// If we were testing C qsort, we'd have to make a copy
// of the array and sort it ourselves and then compare
// x against it, to ensure that qsort was only permuting
// the data, not (for example) overwriting it with zeros.
//
// In go, we don't have to be so paranoid: since the only
// mutating method Sort can call is TestingData.swap,
// it suffices here just to check that the final array is sorted.
if !IntsAreSorted(mdata) {
t.Errorf("%s: ints not sorted", desc)
t.Errorf("\t%v", mdata)
t.FailNow()
}
}
}
}
}
}
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