Add formatting to bandwidth values.

api/bandwidth.go

@@ -22,14 +22,47 @@
 package api
 
 import (
+	"fmt"
+	"math"
 	"sync/atomic"
 
 	"github.com/strukturag/nextcloud-spreed-signaling/internal"
 )
 
+var (
+	Kilobit = BandwidthFromBits(1024)
+	Megabit = BandwidthFromBits(1024) * Kilobit
+	Gigabit = BandwidthFromBits(1024) * Megabit
+)
+
 // Bandwidth stores a bandwidth in bits per second.
 type Bandwidth uint64
 
+func formatWithRemainder(value uint64, divisor uint64, format string) string {
+	if value%divisor == 0 {
+		return fmt.Sprintf("%d %s", value/divisor, format)
+	} else {
+		v := float64(value) / float64(divisor)
+		v = math.Trunc(v*100) / 100
+		return fmt.Sprintf("%.2f %s", v, format)
+	}
+}
+
+// String returns the formatted bandwidth.
+func (b Bandwidth) String() string {
+	if b >= Gigabit {
+		return formatWithRemainder(b.Bits(), Gigabit.Bits(), "Gbps")
+	} else if b >= Megabit {
+		return formatWithRemainder(b.Bits(), Megabit.Bits(), "Mbps")
+	} else if b >= Kilobit {
+		return formatWithRemainder(b.Bits(), Kilobit.Bits(), "Kbps")
+	} else if b > 0 {
+		return fmt.Sprintf("%d bps", b)
+	} else {
+		return "unlimited"
+	}
+}
+
 // Bits returns the bandwidth in bits per second.
 func (b Bandwidth) Bits() uint64 {
 	return uint64(b)
@@ -47,7 +80,7 @@ func BandwidthFromBits(b uint64) Bandwidth {
 
 // BandwithFromBits creates a bandwidth from megabits per second.
 func BandwidthFromMegabits(b uint64) Bandwidth {
-	return Bandwidth(b * 1024 * 1024)
+	return Bandwidth(b) * Megabit
 }
 
 // BandwidthFromBytes creates a bandwidth from bytes per second.

api/bandwidth_test.go

@@ -56,3 +56,54 @@ func TestBandwidth(t *testing.T) {
 	assert.EqualValues(1000, old)
 	assert.EqualValues(2000, a.Load())
 }
+
+func TestBandwidthString(t *testing.T) {
+	t.Parallel()
+
+	assert := assert.New(t)
+	testcases := []struct {
+		value    Bandwidth
+		expected string
+	}{
+		{
+			0,
+			"unlimited",
+		},
+		{
+			BandwidthFromBits(123),
+			"123 bps",
+		},
+		{
+			BandwidthFromBits(1023),
+			"1023 bps",
+		},
+		{
+			BandwidthFromBits(1024),
+			"1 Kbps",
+		},
+		{
+			BandwidthFromBits(1024 + 512),
+			"1.50 Kbps",
+		},
+		{
+			BandwidthFromBits(1024*1024 - 1),
+			"1023.99 Kbps",
+		},
+		{
+			BandwidthFromBits(1024 * 1024),
+			"1 Mbps",
+		},
+		{
+			BandwidthFromBits(1024*1024*1024 - 1),
+			"1023.99 Mbps",
+		},
+		{
+			BandwidthFromBits(1024 * 1024 * 1024),
+			"1 Gbps",
+		},
+	}
+
+	for idx, tc := range testcases {
+		assert.Equal(tc.expected, tc.value.String(), "failed for testcase %d (%d)", idx, tc.value.Bits())
+	}
+}