prec handling

Author: linkdata

sprint_test.go

@@ -26,6 +26,10 @@ func TestSprint(t *testing.T) {
 			1023,
 			"1.00kB",
 		},
+		{
+			999.5,
+			"0.98kB",
+		},
 		{
 			1024 + 512,
 			"1.50kB",

value.go

@@ -14,6 +14,7 @@ func (v Value) String() string {
 
 func (v Value) Format(f fmt.State, verb rune) {
 	var wid, prec int
+	userPrec, hasUserPrec := f.Precision()
 	var scale rune
 	divisor := Value(1024.0)
 	sign := byte(0)
@@ -44,7 +45,13 @@ func (v Value) Format(f fmt.State, verb rune) {
 		sign = '+'
 	}
 
-	if v >= 1000 {
+	scaleAt := Value(1000)
+	if !hasUserPrec {
+		// With default precision (0), 999.5 rounds to 1000.
+		scaleAt = 999.5
+	}
+
+	if v >= scaleAt {
 		for _, scale = range "kMGTPEZYRQ" {
 			v /= divisor
 			if v < 10 {
@@ -67,8 +74,8 @@ func (v Value) Format(f fmt.State, verb rune) {
 	if n, ok := f.Width(); ok {
 		wid = n
 	}
-	if n, ok := f.Precision(); ok {
-		prec = n
+	if hasUserPrec {
+		prec = userPrec
 	}
 
 	var buf []byte

value_test.go

@@ -55,6 +55,21 @@ func TestValue_Format(t *testing.T) {
 			f:    "%b",
 			v:    1,
 		},
+		{
+			name: "0.98kB",
+			f:    "%v",
+			v:    999.5,
+		},
+		{
+			name: "-0.98kB",
+			f:    "%v",
+			v:    -999.5,
+		},
+		{
+			name: "1000B",
+			f:    "%.0v",
+			v:    999.5,
+		},
 		{
 			name: "1.0  ",
 			f:    "%#-5.1v",