1 files changed, 68 insertions, 0 deletions
diff --git a/decor/percentage.go b/decor/percentage.go
new file mode 100644
index 0000000..9709c19
--- /dev/null
+++ b/decor/percentage.go
@@ -0,0 +1,68 @@
+package decor
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/vbauerster/mpb/v8/internal"
+)
+
+var _ fmt.Formatter = percentageType(0)
+
+type percentageType float64
+
+func (s percentageType) Format(st fmt.State, verb rune) {
+	prec := -1
+	switch verb {
+	case 'f', 'e', 'E':
+		prec = 6 // default prec of fmt.Printf("%f|%e|%E")
+		fallthrough
+	case 'b', 'g', 'G', 'x', 'X':
+		if p, ok := st.Precision(); ok {
+			prec = p
+		}
+	default:
+		verb, prec = 'f', 0
+	}
+
+	b := strconv.AppendFloat(make([]byte, 0, 16), float64(s), byte(verb), prec, 64)
+	if st.Flag(' ') {
+		b = append(b, ' ', '%')
+	} else {
+		b = append(b, '%')
+	}
+	_, err := st.Write(b)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Percentage returns percentage decorator. It's a wrapper of NewPercentage.
+func Percentage(wcc ...WC) Decorator {
+	return NewPercentage("% d", wcc...)
+}
+
+// NewPercentage percentage decorator with custom format string.
+//
+//	`format` printf compatible verb
+//
+//	`wcc` optional WC config
+//
+// format examples:
+//
+//	format="%d"    output: "1%"
+//	format="% d"   output: "1 %"
+//	format="%.1f"  output: "1.0%"
+//	format="% .1f" output: "1.0 %"
+//	format="%f"    output: "1.000000%"
+//	format="% f"   output: "1.000000 %"
+func NewPercentage(format string, wcc ...WC) Decorator {
+	if format == "" {
+		format = "% d"
+	}
+	f := func(s Statistics) string {
+		p := internal.Percentage(s.Total, s.Current, 100)
+		return fmt.Sprintf(format, percentageType(p))
+	}
+	return Any(f, wcc...)
+}