write float64

feature_stream_float.go

@@ -36,4 +36,34 @@ func (stream *Stream) WriteFloat32(val float32) {
 	for stream.buf[stream.n - 1] == '0' {
 		stream.n--;
 	}
+}
+
+func (stream *Stream) WriteFloat64(val float64) {
+	if val < 0 {
+		stream.writeByte('-')
+		val = -val
+	}
+	if val > 0x4ffffff {
+		stream.WriteRaw(strconv.FormatFloat(val, 'f', -1, 64));
+		return
+	}
+	precision := 6
+	exp := uint64(1000000) // 6
+	lval := uint64(val * float64(exp) + 0.5)
+	stream.WriteUint64(lval / exp)
+	fval := lval % exp
+	if fval == 0 {
+		return
+	}
+	stream.writeByte('.')
+	if stream.Available() < 10 {
+		stream.Flush()
+	}
+	for p := precision - 1; p > 0 && fval < POW10[p]; p-- {
+		stream.writeByte('0')
+	}
+	stream.WriteUint64(fval);
+	for stream.buf[stream.n - 1] == '0' {
+		stream.n--;
+	}
 }

jsoniter_float_test.go

@@ -58,6 +58,30 @@ func Test_write_float32(t *testing.T) {
 	should.Equal("abcdefg1.123456", buf.String())
 }
 
+func Test_write_float64(t *testing.T) {
+	vals := []float64{0, 1, -1, 99, 0xff, 0xfff, 0xffff, 0xfffff, 0xffffff, 0x4ffffff, 0xfffffff,
+	-0x4ffffff, -0xfffffff, 1.2345, 1.23456, 1.234567, 1.001}
+	for _, val := range vals {
+		t.Run(fmt.Sprintf("%v", val), func(t *testing.T) {
+			should := require.New(t)
+			buf := &bytes.Buffer{}
+			stream := NewStream(buf, 4096)
+			stream.WriteFloat64(val)
+			stream.Flush()
+			should.Nil(stream.Error)
+			should.Equal(strconv.FormatFloat(val, 'f', -1, 64), buf.String())
+		})
+	}
+	should := require.New(t)
+	buf := &bytes.Buffer{}
+	stream := NewStream(buf, 10)
+	stream.WriteRaw("abcdefg")
+	stream.WriteFloat64(1.123456)
+	stream.Flush()
+	should.Nil(stream.Error)
+	should.Equal("abcdefg1.123456", buf.String())
+}
+
 func Benchmark_jsoniter_float(b *testing.B) {
 	b.ReportAllocs()
 	for n := 0; n < b.N; n++ {