[FIX] option -i: now shows the sizes with the correct units

utils/utils.go

@@ -33,6 +33,21 @@ func CalcSizeInByte(number float64, unit string) int64 {
 	return int64(number)
 }
 
+// ByteCountSI turn bytes to SI (decimal) format - https://yourbasic.org/golang/formatting-byte-size-to-human-readable-format/
+func ByteCountSI(b int64) string {
+	const unit = 1000
+	if b < unit {
+		return fmt.Sprintf("%d B", b)
+	}
+	div, exp := int64(unit), 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.1f %cB",
+		float64(b)/float64(div), "kMGTPE"[exp])
+}
+
 // NeedDownloadList return the indices of gallery that need download
 func NeedDownloadList(length int) []int {
 	if config.Pages != "" {

utils/utils_test.go

@@ -57,6 +57,29 @@ func TestCalcSizeInByte(t *testing.T) {
 	}
 }
 
+func TestByteCountSI(t *testing.T) {
+	tests := []struct {
+		Name   string
+		number int64
+		Want   string
+	}{
+		{
+			Name:   "To Kilobytes",
+			number: 752000,
+			Want:   "752.0 kB",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			bytes := ByteCountSI(tt.number)
+
+			if bytes != tt.Want {
+				t.Errorf("Got: %v - Want: %v", bytes, tt.Want)
+			}
+		})
+	}
+}
+
 func TestNeedDownloadList(t *testing.T) {
 	type args struct {
 		len int