From 2701bcc4d2e3f7d25fc0b642e63a2c658e16492a Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Tue, 30 May 2023 11:41:54 +0800
Subject: [PATCH] feat: add Cos, Sin, LCM, GCD function

---
 internal/assert.go        | 47 +++++++++++++++++++++++++++++
 mathutil/mathutil.go      | 63 +++++++++++++++++++++++++++++++++++++++
 mathutil/mathutil_test.go | 58 +++++++++++++++++++++++++++++++++++
 3 files changed, 168 insertions(+)

diff --git a/internal/assert.go b/internal/assert.go
index 3e817d8..ec4954b 100644
--- a/internal/assert.go
+++ b/internal/assert.go
@@ -5,6 +5,7 @@
 package internal
 
 import (
+	"bytes"
 	"fmt"
 	"reflect"
 	"runtime"
@@ -36,6 +37,52 @@ func (a *Assert) Equal(expected, actual interface{}) {
 	}
 }
 
+// EqualValues asserts that two objects are equal or convertable to the same types and equal.
+// https://github.com/stretchr/testify/assert/assertions.go
+func (a *Assert) EqualValues(expected, actual interface{}) {
+	if !objectsAreEqualValues(expected, actual) {
+		makeTestFailed(a.T, a.CaseName, expected, actual)
+	}
+}
+
+func objectsAreEqualValues(expected, actual interface{}) bool {
+	if objectsAreEqual(expected, actual) {
+		return true
+	}
+
+	actualType := reflect.TypeOf(actual)
+	if actualType == nil {
+		return false
+	}
+	expectedValue := reflect.ValueOf(expected)
+	if expectedValue.IsValid() && expectedValue.Type().ConvertibleTo(actualType) {
+		// Attempt comparison after type conversion
+		return reflect.DeepEqual(expectedValue.Convert(actualType).Interface(), actual)
+	}
+
+	return false
+}
+
+func objectsAreEqual(expected, actual interface{}) bool {
+	if expected == nil || actual == nil {
+		return expected == actual
+	}
+
+	exp, ok := expected.([]byte)
+	if !ok {
+		return reflect.DeepEqual(expected, actual)
+	}
+
+	act, ok := actual.([]byte)
+	if !ok {
+		return false
+	}
+	if exp == nil || act == nil {
+		return exp == nil && act == nil
+	}
+	return bytes.Equal(exp, act)
+}
+
 // NotEqual check if expected is not equal with actual
 func (a *Assert) NotEqual(expected, actual interface{}) {
 	if compare(expected, actual) == compareEqual {
diff --git a/mathutil/mathutil.go b/mathutil/mathutil.go
index 1cde95b..35bc1a7 100644
--- a/mathutil/mathutil.go
+++ b/mathutil/mathutil.go
@@ -126,3 +126,66 @@ func IsPrime(n int) bool {
 
 	return true
 }
+
+// GCD return greatest common divisor (GCD) of integers.
+func GCD(integers ...int) int {
+	result := integers[0]
+
+	for k := range integers {
+		result = gcd(integers[k], result)
+
+		if result == 1 {
+			return 1
+		}
+	}
+
+	return result
+}
+
+// find greatest common divisor (GCD)
+func gcd(a, b int) int {
+	if b == 0 {
+		return a
+	}
+
+	return gcd(b, a%b)
+}
+
+// LCM return Least Common Multiple (LCM) of integers.
+func LCM(integers ...int) int {
+	result := integers[0]
+
+	for k := range integers {
+		result = lcm(integers[k], result)
+	}
+
+	return result
+}
+
+// find Least Common Multiple (LCM) via GCD.
+func lcm(a, b int) int {
+	if a == 0 || b == 0 {
+		panic("lcm function: provide non zero integers only.")
+	}
+	return a * b / gcd(a, b)
+}
+
+// Cos returns the cosine of the radian argument.
+func Cos(radian float64, precision ...int) float64 {
+	t := 1.0 / (2.0 * math.Pi)
+	radian *= t
+	radian -= 0.25 + math.Floor(radian+0.25)
+	radian *= 16.0 * (math.Abs(radian) - 0.5)
+	radian += 0.225 * radian * (math.Abs(radian) - 1.0)
+
+	if len(precision) == 1 {
+		return TruncRound(radian, precision[0])
+	}
+
+	return TruncRound(radian, 3)
+}
+
+// Cos returns the sine of the radian argument.
+func Sin(radian float64, precision ...int) float64 {
+	return Cos((math.Pi / 2) - radian)
+}
diff --git a/mathutil/mathutil_test.go b/mathutil/mathutil_test.go
index fa15e3b..a10f5d0 100644
--- a/mathutil/mathutil_test.go
+++ b/mathutil/mathutil_test.go
@@ -114,3 +114,61 @@ func TestIsPrime(t *testing.T) {
 	assert.Equal(true, IsPrime(3))
 	assert.Equal(false, IsPrime(4))
 }
+
+func TestGCD(t *testing.T) {
+	assert := internal.NewAssert(t, "TestGCD")
+
+	assert.Equal(1, GCD(1, 1))
+	assert.Equal(1, GCD(1, -1))
+	assert.Equal(-1, GCD(-1, 1))
+	assert.Equal(-1, GCD(-1, -1))
+
+	assert.Equal(1, GCD(1, 0))
+	assert.Equal(1, GCD(0, 1))
+	assert.Equal(-1, GCD(-1, 0))
+	assert.Equal(-1, GCD(0, -1))
+
+	assert.Equal(1, GCD(1, -2))
+	assert.Equal(1, GCD(-2, 1))
+	assert.Equal(-1, GCD(-1, 2))
+	assert.Equal(-1, GCD(2, -1))
+
+	assert.Equal(-1, GCD(-1, -2))
+	assert.Equal(-1, GCD(-2, -1))
+
+	assert.Equal(-9, GCD(-27, -36))
+	assert.Equal(3, GCD(3, 6, 9))
+}
+
+func TestLCM(t *testing.T) {
+	assert := internal.NewAssert(t, "TestLCM")
+
+	assert.Equal(1, LCM(1))
+	assert.Equal(-1, LCM(-1))
+	assert.Equal(-1, LCM(1, -1))
+	assert.Equal(1, LCM(-1, 1))
+	assert.Equal(1, LCM(1, 1))
+	assert.Equal(-1, LCM(-1, -1))
+	assert.Equal(2, LCM(1, 2))
+	assert.Equal(18, LCM(3, 6, 9))
+}
+
+func TestCos(t *testing.T) {
+	assert := internal.NewAssert(t, "TestCos")
+
+	assert.EqualValues(1, Cos(0))
+	assert.EqualValues(-0.447, Cos(90))
+	assert.EqualValues(-0.598, Cos(180))
+	assert.EqualValues(-1, Cos(math.Pi))
+	assert.EqualValues(0, Cos(math.Pi/2))
+}
+
+func TestSin(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSin")
+
+	assert.EqualValues(0, Sin(0))
+	assert.EqualValues(0.894, Sin(90))
+	assert.EqualValues(-0.801, Sin(180))
+	assert.EqualValues(0, Sin(math.Pi))
+	assert.EqualValues(1, Sin(math.Pi/2))
+}