Merge pull request #142 from rebuy-de/add-formatting

Add functions for byte formatting

pkg/formatutil/bytes.go

@@ -0,0 +1,31 @@
+package formatutil
+
+import "fmt"
+
+func ByteFormatSI(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])
+}
+
+func ByteFormatIEC(b int64) string {
+	const unit = 1024
+	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 %ciB",
+		float64(b)/float64(div), "KMGTPE"[exp])
+}

pkg/formatutil/bytes_test.go

@@ -0,0 +1,34 @@
+package formatutil
+
+import "testing"
+
+type testCaseByteFormatter struct {
+	input    int64
+	expected string
+}
+
+func TestByteFormatting(t *testing.T) {
+	casesIEC := []testCaseByteFormatter{
+		{16516, "16.1 KiB"},
+		{46564534534, "43.4 GiB"},
+		{9845345734653745, "8.7 PiB"},
+	}
+
+	for _, testcase := range casesIEC {
+		if output := ByteFormatIEC(testcase.input); output != testcase.expected {
+			t.Errorf("Output %q not equal to expected %q", output, testcase.expected)
+		}
+	}
+
+	casesSI := []testCaseByteFormatter{
+		{16516, "16.5 kB"},
+		{46564534534, "46.6 GB"},
+		{9845345734653745, "9.8 PB"},
+	}
+
+	for _, testcase := range casesSI {
+		if output := ByteFormatSI(testcase.input); output != testcase.expected {
+			t.Errorf("Output %q not equal to expected %q", output, testcase.expected)
+		}
+	}
+}