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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package bits
import (
"reflect"
"testing"
)
func TestTrailingZeros64(t *testing.T) {
for i := 0; i <= 64; i++ {
n := uint64(1) << uint(i)
if got, want := TrailingZeros64(n), i; got != want {
t.Errorf("TrailingZeros64(%#x): got %d, wanted %d", n, got, want)
}
}
for i := 0; i < 64; i++ {
n := ^uint64(0) << uint(i)
if got, want := TrailingZeros64(n), i; got != want {
t.Errorf("TrailingZeros64(%#x): got %d, wanted %d", n, got, want)
}
}
for i := 0; i < 64; i++ {
n := ^uint64(0) >> uint(i)
if got, want := TrailingZeros64(n), 0; got != want {
t.Errorf("TrailingZeros64(%#x): got %d, wanted %d", n, got, want)
}
}
}
func TestMostSignificantOne64(t *testing.T) {
for i := 0; i <= 64; i++ {
n := uint64(1) << uint(i)
if got, want := MostSignificantOne64(n), i; got != want {
t.Errorf("MostSignificantOne64(%#x): got %d, wanted %d", n, got, want)
}
}
for i := 0; i < 64; i++ {
n := ^uint64(0) >> uint(i)
if got, want := MostSignificantOne64(n), 63-i; got != want {
t.Errorf("MostSignificantOne64(%#x): got %d, wanted %d", n, got, want)
}
}
for i := 0; i < 64; i++ {
n := ^uint64(0) << uint(i)
if got, want := MostSignificantOne64(n), 63; got != want {
t.Errorf("MostSignificantOne64(%#x): got %d, wanted %d", n, got, want)
}
}
}
func TestForEachSetBit64(t *testing.T) {
for _, want := range [][]int{
{},
{0},
{1},
{63},
{0, 1},
{1, 3, 5},
{0, 63},
} {
n := Mask64(want...)
// "Slice values are deeply equal when ... they are both nil or both
// non-nil ..."
got := make([]int, 0)
ForEachSetBit64(n, func(i int) {
got = append(got, i)
})
if !reflect.DeepEqual(got, want) {
t.Errorf("ForEachSetBit64(%#x): iterated bits %v, wanted %v", n, got, want)
}
}
}
func TestIsOn(t *testing.T) {
type spec struct {
mask uint64
bits uint64
any bool
all bool
}
for _, s := range []spec{
{Mask64(0), Mask64(0), true, true},
{Mask64(63), Mask64(63), true, true},
{Mask64(0), Mask64(1), false, false},
{Mask64(0), Mask64(0, 1), true, false},
{Mask64(1, 63), Mask64(1), true, true},
{Mask64(1, 63), Mask64(1, 63), true, true},
{Mask64(1, 63), Mask64(0, 1, 63), true, false},
{Mask64(1, 63), Mask64(0, 62), false, false},
} {
if ok := IsAnyOn64(s.mask, s.bits); ok != s.any {
t.Errorf("IsAnyOn(%#x, %#x) = %v, wanted: %v", s.mask, s.bits, ok, s.any)
}
if ok := IsOn64(s.mask, s.bits); ok != s.all {
t.Errorf("IsOn(%#x, %#x) = %v, wanted: %v", s.mask, s.bits, ok, s.all)
}
}
}
func TestIsPowerOfTwo(t *testing.T) {
for _, tc := range []struct {
v uint64
want bool
}{
{v: 0, want: false},
{v: 1, want: true},
{v: 2, want: true},
{v: 3, want: false},
{v: 4, want: true},
{v: 5, want: false},
} {
if got := IsPowerOfTwo64(tc.v); got != tc.want {
t.Errorf("IsPowerOfTwo(%d) = %t, want: %t", tc.v, got, tc.want)
}
}
}
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