Jan Dubsky
50 lines
1006 B
Go
50 lines
1006 B
Go
package puddle
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import (
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"math"
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"math/rand"
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"testing"
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"time"
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"github.com/stretchr/testify/require"
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)
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func TestLog2Uint(t *testing.T) {
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r := require.New(t)
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r.Equal(uint8(0), log2Int(1))
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r.Equal(uint8(0), log2Int[uint64](1))
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r.Equal(uint8(1), log2Int[uint32](2))
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r.Equal(uint8(7), log2Int[uint8](math.MaxUint8))
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r.Equal(uint8(15), log2Int[uint16](math.MaxUint16))
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r.Equal(uint8(31), log2Int[uint32](math.MaxUint32))
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r.Equal(uint8(63), log2Int[uint64](math.MaxUint64))
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r.Panics(func() { log2Int[uint64](0) })
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r.Panics(func() { log2Int[int64](-1) })
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}
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func FuzzLog2Uint(f *testing.F) {
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const cnt = 1000
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rand := rand.New(rand.NewSource(time.Now().UnixNano()))
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for i := 0; i < cnt; i++ {
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val := uint64(rand.Int63())
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// val + 1 not to test val == 0.
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f.Add(val + 1)
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}
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f.Fuzz(func(t *testing.T, val uint64) {
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var mx uint8
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for i := 63; i >= 0; i-- {
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mask := uint64(1) << i
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if mask&val != 0 {
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mx = uint8(i)
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break
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}
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}
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require.Equal(t, mx, log2Int(val))
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})
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}
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