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// Copyright 2012 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 runtime_test
import (
"runtime"
"strings"
"testing"
)
// Strings and slices that don't escape and fit into tmpBuf are stack allocated,
// which defeats using AllocsPerRun to test other optimizations.
const sizeNoStack = 100
func BenchmarkCompareStringEqual(b *testing.B) {
bytes := []byte("Hello Gophers!")
s1, s2 := string(bytes), string(bytes)
for i := 0; i < b.N; i++ {
if s1 != s2 {
b.Fatal("s1 != s2")
}
}
}
func BenchmarkCompareStringIdentical(b *testing.B) {
s1 := "Hello Gophers!"
s2 := s1
for i := 0; i < b.N; i++ {
if s1 != s2 {
b.Fatal("s1 != s2")
}
}
}
func BenchmarkCompareStringSameLength(b *testing.B) {
s1 := "Hello Gophers!"
s2 := "Hello, Gophers"
for i := 0; i < b.N; i++ {
if s1 == s2 {
b.Fatal("s1 == s2")
}
}
}
func BenchmarkCompareStringDifferentLength(b *testing.B) {
s1 := "Hello Gophers!"
s2 := "Hello, Gophers!"
for i := 0; i < b.N; i++ {
if s1 == s2 {
b.Fatal("s1 == s2")
}
}
}
func BenchmarkCompareStringBigUnaligned(b *testing.B) {
bytes := make([]byte, 0, 1<<20)
for len(bytes) < 1<<20 {
bytes = append(bytes, "Hello Gophers!"...)
}
s1, s2 := string(bytes), "hello"+string(bytes)
for i := 0; i < b.N; i++ {
if s1 != s2[len("hello"):] {
b.Fatal("s1 != s2")
}
}
b.SetBytes(int64(len(s1)))
}
func BenchmarkCompareStringBig(b *testing.B) {
bytes := make([]byte, 0, 1<<20)
for len(bytes) < 1<<20 {
bytes = append(bytes, "Hello Gophers!"...)
}
s1, s2 := string(bytes), string(bytes)
for i := 0; i < b.N; i++ {
if s1 != s2 {
b.Fatal("s1 != s2")
}
}
b.SetBytes(int64(len(s1)))
}
func BenchmarkRuneIterate(b *testing.B) {
bytes := make([]byte, 100)
for i := range bytes {
bytes[i] = byte('A')
}
s := string(bytes)
for i := 0; i < b.N; i++ {
for range s {
}
}
}
func BenchmarkRuneIterate2(b *testing.B) {
bytes := make([]byte, 100)
for i := range bytes {
bytes[i] = byte('A')
}
s := string(bytes)
for i := 0; i < b.N; i++ {
for range s {
}
}
}
func BenchmarkArrayEqual(b *testing.B) {
a1 := [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
a2 := [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
b.ResetTimer()
for i := 0; i < b.N; i++ {
if a1 != a2 {
b.Fatal("not equal")
}
}
}
func TestStringW(t *testing.T) {
strings := []string{
"hello",
"a\u5566\u7788b",
}
for _, s := range strings {
var b []uint16
for _, c := range s {
b = append(b, uint16(c))
if c != rune(uint16(c)) {
t.Errorf("bad test: stringW can't handle >16 bit runes")
}
}
b = append(b, 0)
r := runtime.GostringW(b)
if r != s {
t.Errorf("gostringW(%v) = %s, want %s", b, r, s)
}
}
}
func TestLargeStringConcat(t *testing.T) {
output := runTestProg(t, "testprog", "stringconcat")
want := "panic: " + strings.Repeat("0", 1<<10) + strings.Repeat("1", 1<<10) +
strings.Repeat("2", 1<<10) + strings.Repeat("3", 1<<10)
if !strings.HasPrefix(output, want) {
t.Fatalf("output does not start with %q:\n%s", want, output)
}
}
func TestGostringnocopy(t *testing.T) {
max := *runtime.Maxstring
b := make([]byte, max+10)
for i := uintptr(0); i < max+9; i++ {
b[i] = 'a'
}
_ = runtime.Gostringnocopy(&b[0])
newmax := *runtime.Maxstring
if newmax != max+9 {
t.Errorf("want %d, got %d", max+9, newmax)
}
}
func TestCompareTempString(t *testing.T) {
s := strings.Repeat("x", sizeNoStack)
b := []byte(s)
n := testing.AllocsPerRun(1000, func() {
if string(b) != s {
t.Fatalf("strings are not equal: '%v' and '%v'", string(b), s)
}
if string(b) == s {
} else {
t.Fatalf("strings are not equal: '%v' and '%v'", string(b), s)
}
})
if n != 0 {
t.Fatalf("want 0 allocs, got %v", n)
}
}
func TestStringOnStack(t *testing.T) {
s := ""
for i := 0; i < 3; i++ {
s = "a" + s + "b" + s + "c"
}
if want := "aaabcbabccbaabcbabccc"; s != want {
t.Fatalf("want: '%v', got '%v'", want, s)
}
}
func TestIntString(t *testing.T) {
// Non-escaping result of intstring.
s := ""
for i := 0; i < 4; i++ {
s += string(i+'0') + string(i+'0'+1)
}
if want := "01122334"; s != want {
t.Fatalf("want '%v', got '%v'", want, s)
}
// Escaping result of intstring.
var a [4]string
for i := 0; i < 4; i++ {
a[i] = string(i + '0')
}
s = a[0] + a[1] + a[2] + a[3]
if want := "0123"; s != want {
t.Fatalf("want '%v', got '%v'", want, s)
}
}
func TestIntStringAllocs(t *testing.T) {
unknown := '0'
n := testing.AllocsPerRun(1000, func() {
s1 := string(unknown)
s2 := string(unknown + 1)
if s1 == s2 {
t.Fatalf("bad")
}
})
if n != 0 {
t.Fatalf("want 0 allocs, got %v", n)
}
}
func TestRangeStringCast(t *testing.T) {
s := strings.Repeat("x", sizeNoStack)
n := testing.AllocsPerRun(1000, func() {
for i, c := range []byte(s) {
if c != s[i] {
t.Fatalf("want '%c' at pos %v, got '%c'", s[i], i, c)
}
}
})
if n != 0 {
t.Fatalf("want 0 allocs, got %v", n)
}
}
func isZeroed(b []byte) bool {
for _, x := range b {
if x != 0 {
return false
}
}
return true
}
func isZeroedR(r []rune) bool {
for _, x := range r {
if x != 0 {
return false
}
}
return true
}
func TestString2Slice(t *testing.T) {
// Make sure we don't return slices that expose
// an unzeroed section of stack-allocated temp buf
// between len and cap. See issue 14232.
s := "foo┼ż"
b := ([]byte)(s)
if !isZeroed(b[len(b):cap(b)]) {
t.Errorf("extra bytes not zeroed")
}
r := ([]rune)(s)
if !isZeroedR(r[len(r):cap(r)]) {
t.Errorf("extra runes not zeroed")
}
}