02-06_sign_test.go

package hd_test

import (
	"fmt"
	"math"
	"testing"

	hd "github.com/nikolaydubina/go-hackers-delight"
)

func ExampleExtendSign7_notExtended() {
	fmt.Printf("%08b", hd.ExtendSign7(0b0010_1010))
	// Output: 00101010
}

func ExampleExtendSign7_extended() {
	fmt.Printf("%08b", hd.ExtendSign7(0b1110_1010))
	// Output: 11111111111111111111111111101010
}

func ExampleExtendSign7Two_notExtended() {
	fmt.Printf("%08b", hd.ExtendSign7Two(0b0010_1010))
	// Output: 00101010
}

func ExampleExtendSign7Two_extended() {
	fmt.Printf("%08b", hd.ExtendSign7Two(0b1110_1010))
	// Output: 11111111111111111111111111101010
}

func ExampleExtendSign7Three_notExtended() {
	fmt.Printf("%08b", hd.ExtendSign7Three(0b0010_1010))
	// Output: 00101010
}

func ExampleExtendSign7Three_extended() {
	fmt.Printf("%08b", hd.ExtendSign7Three(0b1110_1010))
	// Output: 11111111111111111111111111101010
}

func ExampleShiftRightSignedFromUnsigned() {
	fmt.Printf("%08b", hd.ShiftRightSignedFromUnsigned(0b11111111111111111111111111101010, 2))
	// Output: 11111111111111111111111111111010
}

func ExampleShiftRightSignedFromUnsigned2() {
	fmt.Printf("%08b", hd.ShiftRightSignedFromUnsigned2(0b11111111111111111111111111101010, 2))
	// Output: 11111111111111111111111111111010
}

func ExampleShiftRightSignedFromUnsigned3() {
	fmt.Printf("%08b", hd.ShiftRightSignedFromUnsigned3(0b11111111111111111111111111101010, 2))
	// Output: 11111111111111111111111111111010
}

func ExampleShiftRightSignedFromUnsigned4() {
	fmt.Printf("%08b", hd.ShiftRightSignedFromUnsigned4(0b11111111111111111111111111101010, 2))
	// Output: 11111111111111111111111111111010
}

func ExampleShiftRightSignedFromUnsigned5() {
	fmt.Printf("%08b", hd.ShiftRightSignedFromUnsigned5(0b11111111111111111111111111101010, 2))
	// Output: 11111111111111111111111111111010
}

func ExampleSign() {
	fmt.Println(hd.Sign(-10), hd.Sign(10), hd.Sign(0))
	// Output: -1 1 0
}

func ExampleIsMostSignificantSet_int32() {
	fmt.Println(hd.IsMostSignificantSet(int32(-1)), hd.IsMostSignificantSet(int32(1)), hd.IsMostSignificantSet(int32(math.MaxInt32)))
	// Output: true false false
}

func ExampleIsMostSignificantSet_uint32() {
	fmt.Println(hd.IsMostSignificantSet(uint32(0xFFFFFFFF)), hd.IsMostSignificantSet(uint32(10)))
	// Output: true false
}

func sign[T hd.Signed](x T) T {
	switch {
	case x > 0:
		return 1
	case x < 0:
		return -1
	default:
		return 0
	}
}

func FuzzSign(f *testing.F) {
	for _, x := range fuzzInt32 {
		f.Add(x)
	}
	f.Fuzz(func(t *testing.T, x int32) {
		exp := sign(x)
		got := hd.Sign(x)
		if got != exp {
			t.Error("x", x, "got", got, "exp", exp)
		}
	})
}

func ExampleISIGN() {
	fmt.Println(hd.ISIGN(10, -100000), hd.ISIGN(-10, 100000))
	// Output: -10 10
}

func isign[T hd.Signed](x, y T) T {
	v := x
	if v < 0 {
		v = -v
	}
	if y < 0 {
		v = -v
	}
	return v
}

func fuzzISIGN[T hd.Signed](t *testing.T, x, y T) {
	exp := isign(x, y)
	got := [...]T{
		hd.ISIGN(x, y),
		hd.ISIGN2(x, y),
		hd.ISIGN3(x, y),
		hd.ISIGN4(x, y),
	}
	for i, q := range got {
		if q != exp {
			t.Error(i, x, y, "got", q, "exp", exp)
		}
	}
}

func FuzzISIGN_int32(f *testing.F) {
	for _, x := range fuzzInt32 {
		for _, y := range fuzzInt32 {
			f.Add(x, y)
		}
	}
	f.Fuzz(fuzzISIGN[int32])
}

func FuzzISIGN_int16(f *testing.F) { f.Fuzz(fuzzISIGN[int16]) }

func FuzzISIGN_int64(f *testing.F) { f.Fuzz(fuzzISIGN[int64]) }