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// Copyright 2013 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 bytes_test
import (
. "bytes"
"internal/testenv"
"testing"
)
var compareTests = []struct {
a, b []byte
i int
}{
{[]byte(""), []byte(""), 0},
{[]byte("a"), []byte(""), 1},
{[]byte(""), []byte("a"), -1},
{[]byte("abc"), []byte("abc"), 0},
{[]byte("abd"), []byte("abc"), 1},
{[]byte("abc"), []byte("abd"), -1},
{[]byte("ab"), []byte("abc"), -1},
{[]byte("abc"), []byte("ab"), 1},
{[]byte("x"), []byte("ab"), 1},
{[]byte("ab"), []byte("x"), -1},
{[]byte("x"), []byte("a"), 1},
{[]byte("b"), []byte("x"), -1},
// test runtime·memeq's chunked implementation
{[]byte("abcdefgh"), []byte("abcdefgh"), 0},
{[]byte("abcdefghi"), []byte("abcdefghi"), 0},
{[]byte("abcdefghi"), []byte("abcdefghj"), -1},
{[]byte("abcdefghj"), []byte("abcdefghi"), 1},
// nil tests
{nil, nil, 0},
{[]byte(""), nil, 0},
{nil, []byte(""), 0},
{[]byte("a"), nil, 1},
{nil, []byte("a"), -1},
}
func TestCompare(t *testing.T) {
for _, tt := range compareTests {
numShifts := 16
buffer := make([]byte, len(tt.b)+numShifts)
// vary the input alignment of tt.b
for offset := 0; offset <= numShifts; offset++ {
shiftedB := buffer[offset : len(tt.b)+offset]
copy(shiftedB, tt.b)
cmp := Compare(tt.a, shiftedB)
if cmp != tt.i {
t.Errorf(`Compare(%q, %q), offset %d = %v; want %v`, tt.a, tt.b, offset, cmp, tt.i)
}
}
}
}
func TestCompareIdenticalSlice(t *testing.T) {
var b = []byte("Hello Gophers!")
if Compare(b, b) != 0 {
t.Error("b != b")
}
if Compare(b, b[:1]) != 1 {
t.Error("b > b[:1] failed")
}
}
func TestCompareBytes(t *testing.T) {
lengths := make([]int, 0) // lengths to test in ascending order
for i := 0; i <= 128; i++ {
lengths = append(lengths, i)
}
lengths = append(lengths, 256, 512, 1024, 1333, 4095, 4096, 4097)
if !testing.Short() || testenv.Builder() != "" {
lengths = append(lengths, 65535, 65536, 65537, 99999)
}
n := lengths[len(lengths)-1]
a := make([]byte, n+1)
b := make([]byte, n+1)
for _, len := range lengths {
// randomish but deterministic data. No 0 or 255.
for i := 0; i < len; i++ {
a[i] = byte(1 + 31*i%254)
b[i] = byte(1 + 31*i%254)
}
// data past the end is different
for i := len; i <= n; i++ {
a[i] = 8
b[i] = 9
}
cmp := Compare(a[:len], b[:len])
if cmp != 0 {
t.Errorf(`CompareIdentical(%d) = %d`, len, cmp)
}
if len > 0 {
cmp = Compare(a[:len-1], b[:len])
if cmp != -1 {
t.Errorf(`CompareAshorter(%d) = %d`, len, cmp)
}
cmp = Compare(a[:len], b[:len-1])
if cmp != 1 {
t.Errorf(`CompareBshorter(%d) = %d`, len, cmp)
}
}
for k := 0; k < len; k++ {
b[k] = a[k] - 1
cmp = Compare(a[:len], b[:len])
if cmp != 1 {
t.Errorf(`CompareAbigger(%d,%d) = %d`, len, k, cmp)
}
b[k] = a[k] + 1
cmp = Compare(a[:len], b[:len])
if cmp != -1 {
t.Errorf(`CompareBbigger(%d,%d) = %d`, len, k, cmp)
}
b[k] = a[k]
}
}
}
func TestEndianBaseCompare(t *testing.T) {
// This test compares byte slices that are almost identical, except one
// difference that for some j, a[j]>b[j] and a[j+1]<b[j+1]. If the implementation
// compares large chunks with wrong endianness, it gets wrong result.
// no vector register is larger than 512 bytes for now
const maxLength = 512
a := make([]byte, maxLength)
b := make([]byte, maxLength)
// randomish but deterministic data. No 0 or 255.
for i := 0; i < maxLength; i++ {
a[i] = byte(1 + 31*i%254)
b[i] = byte(1 + 31*i%254)
}
for i := 2; i <= maxLength; i <<= 1 {
for j := 0; j < i-1; j++ {
a[j] = b[j] - 1
a[j+1] = b[j+1] + 1
cmp := Compare(a[:i], b[:i])
if cmp != -1 {
t.Errorf(`CompareBbigger(%d,%d) = %d`, i, j, cmp)
}
a[j] = b[j] + 1
a[j+1] = b[j+1] - 1
cmp = Compare(a[:i], b[:i])
if cmp != 1 {
t.Errorf(`CompareAbigger(%d,%d) = %d`, i, j, cmp)
}
a[j] = b[j]
a[j+1] = b[j+1]
}
}
}
func BenchmarkCompareBytesEqual(b *testing.B) {
b1 := []byte("Hello Gophers!")
b2 := []byte("Hello Gophers!")
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 0 {
b.Fatal("b1 != b2")
}
}
}
func BenchmarkCompareBytesToNil(b *testing.B) {
b1 := []byte("Hello Gophers!")
var b2 []byte
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 1 {
b.Fatal("b1 > b2 failed")
}
}
}
func BenchmarkCompareBytesEmpty(b *testing.B) {
b1 := []byte("")
b2 := b1
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 0 {
b.Fatal("b1 != b2")
}
}
}
func BenchmarkCompareBytesIdentical(b *testing.B) {
b1 := []byte("Hello Gophers!")
b2 := b1
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 0 {
b.Fatal("b1 != b2")
}
}
}
func BenchmarkCompareBytesSameLength(b *testing.B) {
b1 := []byte("Hello Gophers!")
b2 := []byte("Hello, Gophers")
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != -1 {
b.Fatal("b1 < b2 failed")
}
}
}
func BenchmarkCompareBytesDifferentLength(b *testing.B) {
b1 := []byte("Hello Gophers!")
b2 := []byte("Hello, Gophers!")
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != -1 {
b.Fatal("b1 < b2 failed")
}
}
}
func BenchmarkCompareBytesBigUnaligned(b *testing.B) {
b.StopTimer()
b1 := make([]byte, 0, 1<<20)
for len(b1) < 1<<20 {
b1 = append(b1, "Hello Gophers!"...)
}
b2 := append([]byte("hello"), b1...)
b.StartTimer()
for i := 0; i < b.N; i++ {
if Compare(b1, b2[len("hello"):]) != 0 {
b.Fatal("b1 != b2")
}
}
b.SetBytes(int64(len(b1)))
}
func BenchmarkCompareBytesBig(b *testing.B) {
b.StopTimer()
b1 := make([]byte, 0, 1<<20)
for len(b1) < 1<<20 {
b1 = append(b1, "Hello Gophers!"...)
}
b2 := append([]byte{}, b1...)
b.StartTimer()
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 0 {
b.Fatal("b1 != b2")
}
}
b.SetBytes(int64(len(b1)))
}
func BenchmarkCompareBytesBigIdentical(b *testing.B) {
b.StopTimer()
b1 := make([]byte, 0, 1<<20)
for len(b1) < 1<<20 {
b1 = append(b1, "Hello Gophers!"...)
}
b2 := b1
b.StartTimer()
for i := 0; i < b.N; i++ {
if Compare(b1, b2) != 0 {
b.Fatal("b1 != b2")
}
}
b.SetBytes(int64(len(b1)))
}