Add template func FileSize

modules/base/template.go

@@ -21,6 +21,7 @@ var TemplateFuncs template.FuncMap = map[string]interface{}{
 	},
 	"str2html":   Str2html,
 	"TimeSince":  TimeSince,
+	"FileSize":   FileSize,
 	"Subtract":   Subtract,
 	"ActionIcon": ActionIcon,
 	"ActionDesc": ActionDesc,

modules/base/tool.go

@@ -8,6 +8,7 @@ import (
 	"crypto/md5"
 	"encoding/hex"
 	"fmt"
+	"math"
 	"strings"
 	"time"
 )
@@ -80,6 +81,51 @@ func TimeSince(then time.Time) string {
 	return then.String()
 }
 
+const (
+	Byte  = 1
+	KByte = Byte * 1024
+	MByte = KByte * 1024
+	GByte = MByte * 1024
+	TByte = GByte * 1024
+	PByte = TByte * 1024
+	EByte = PByte * 1024
+)
+
+var bytesSizeTable = map[string]uint64{
+	"b":  Byte,
+	"kb": KByte,
+	"mb": MByte,
+	"gb": GByte,
+	"tb": TByte,
+	"pb": PByte,
+	"eb": EByte,
+}
+
+func logn(n, b float64) float64 {
+	return math.Log(n) / math.Log(b)
+}
+
+func humanateBytes(s uint64, base float64, sizes []string) string {
+	if s < 10 {
+		return fmt.Sprintf("%dB", s)
+	}
+	e := math.Floor(logn(float64(s), base))
+	suffix := sizes[int(e)]
+	val := float64(s) / math.Pow(base, math.Floor(e))
+	f := "%.0f"
+	if val < 10 {
+		f = "%.1f"
+	}
+
+	return fmt.Sprintf(f+"%s", val, suffix)
+}
+
+// FileSize calculates the file size and generate user-friendly string.
+func FileSize(s uint64) string {
+	sizes := []string{"B", "KB", "MB", "GB", "TB", "PB", "EB"}
+	return humanateBytes(uint64(s), 1024, sizes)
+}
+
 // Subtract deals with subtraction of all types of number.
 func Subtract(left interface{}, right interface{}) interface{} {
 	var rleft, rright int64