Change endianness to BigEndian :(

Change endianness to BigEndian (ಥ﹏ಥ), spec has been updated to achieve
compatibility with js & smart contracts & circuits implementations.

common/float16_test.go

@@ -0,0 +1,131 @@
+package common
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConversions(t *testing.T) {
+	testVector := map[Float16]string{
+		0x307B: "123000000",
+		0x1DC6: "454500",
+		0xFFFF: "10235000000000000000000000000000000",
+		0x0000: "0",
+		0x0400: "0",
+		0x0001: "1",
+		0x0401: "1",
+		0x0800: "0",
+		0x0c00: "5",
+		0x0801: "10",
+		0x0c01: "15",
+	}
+
+	for test := range testVector {
+		fix := test.BigInt()
+
+		assert.Equal(t, fix.String(), testVector[test])
+
+		bi := big.NewInt(0)
+		bi.SetString(testVector[test], 10)
+
+		fl, err := NewFloat16(bi)
+		assert.Equal(t, nil, err)
+
+		fx2 := fl.BigInt()
+		assert.Equal(t, fx2.String(), testVector[test])
+	}
+}
+
+func TestFloorFix2Float(t *testing.T) {
+	testVector := map[string]Float16{
+		"87999990000000000": 0x776f,
+		"87950000000000001": 0x776f,
+		"87950000000000000": 0x776f,
+		"87949999999999999": 0x736f,
+	}
+
+	for test := range testVector {
+		bi := big.NewInt(0)
+		bi.SetString(test, 10)
+
+		testFloat := NewFloat16Floor(bi)
+
+		assert.Equal(t, testFloat, testVector[test])
+	}
+}
+
+func TestConversionLosses(t *testing.T) {
+	a := big.NewInt(1000)
+	b, err := NewFloat16(a)
+	assert.Equal(t, nil, err)
+	c := b.BigInt()
+	assert.Equal(t, c, a)
+
+	a = big.NewInt(1024)
+	b, err = NewFloat16(a)
+	assert.Equal(t, ErrRoundingLoss, err)
+	c = b.BigInt()
+	assert.NotEqual(t, c, a)
+
+	a = big.NewInt(32767)
+	b, err = NewFloat16(a)
+	assert.Equal(t, ErrRoundingLoss, err)
+	c = b.BigInt()
+	assert.NotEqual(t, c, a)
+
+	a = big.NewInt(32768)
+	b, err = NewFloat16(a)
+	assert.Equal(t, ErrRoundingLoss, err)
+	c = b.BigInt()
+	assert.NotEqual(t, c, a)
+
+	a = big.NewInt(65536000)
+	b, err = NewFloat16(a)
+	assert.Equal(t, ErrRoundingLoss, err)
+	c = b.BigInt()
+	assert.NotEqual(t, c, a)
+}
+
+func BenchmarkFloat16(b *testing.B) {
+	newBigInt := func(s string) *big.Int {
+		bigInt, ok := new(big.Int).SetString(s, 10)
+		if !ok {
+			panic("Bad big int")
+		}
+		return bigInt
+	}
+	type pair struct {
+		Float16 Float16
+		BigInt  *big.Int
+	}
+	testVector := []pair{
+		{0x307B, newBigInt("123000000")},
+		{0x1DC6, newBigInt("454500")},
+		{0xFFFF, newBigInt("10235000000000000000000000000000000")},
+		{0x0000, newBigInt("0")},
+		{0x0400, newBigInt("0")},
+		{0x0001, newBigInt("1")},
+		{0x0401, newBigInt("1")},
+		{0x0800, newBigInt("0")},
+		{0x0c00, newBigInt("5")},
+		{0x0801, newBigInt("10")},
+		{0x0c01, newBigInt("15")},
+	}
+	b.Run("floorFix2Float()", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			NewFloat16Floor(testVector[i%len(testVector)].BigInt)
+		}
+	})
+	b.Run("NewFloat16()", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			_, _ = NewFloat16(testVector[i%len(testVector)].BigInt)
+		}
+	})
+	b.Run("Float16.BigInt()", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			testVector[i%len(testVector)].Float16.BigInt()
+		}
+	})
+}