add memory usage

main.go

@@ -6,6 +6,7 @@ import (
 	"go-comic-converter/internal/epub"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 )
 
@@ -61,6 +62,7 @@ type Option struct {
 	Quality  int
 	NoCrop   bool
 	LimitMb  int
+	PrintMem bool
 }
 
 func (o *Option) String() string {
@@ -88,6 +90,7 @@ Options:
     Quality : %d
     Crop    : %v
     LimitMb : %s
+    PrintMem: %v
 `,
 		o.Input,
 		o.Output,
@@ -100,6 +103,27 @@ Options:
 		o.Quality,
 		!o.NoCrop,
 		limitmb,
+		o.PrintMem,
+	)
+}
+
+func PrintMemUsage() {
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	bToMb := func(b uint64) uint64 { return b / 1024 / 1024 }
+
+	// For info on each, see: https://golang.org/pkg/runtime/#MemStats
+	fmt.Printf(`Memory Usage:
+	Alloc     : %v MiB
+	TotalAlloc: %v MiB
+	Sys       : %v MiB
+	NumGC     : %v
+`,
+		bToMb(m.Alloc),
+		bToMb(m.TotalAlloc),
+		bToMb(m.Sys),
+		m.NumGC,
 	)
 }
 
@@ -123,6 +147,7 @@ func main() {
 	flag.IntVar(&opt.Quality, "quality", 85, "Quality of the image")
 	flag.BoolVar(&opt.NoCrop, "nocrop", false, "Disable cropping")
 	flag.IntVar(&opt.LimitMb, "limitmb", 0, "Limit size of the ePub: Default nolimit (0), Minimum 20")
+	flag.BoolVar(&opt.PrintMem, "printmem", false, "Print memory usage")
 	flag.Parse()
 
 	if opt.Input == "" {
@@ -183,5 +208,8 @@ func main() {
 		os.Exit(1)
 	}
 
+	if opt.PrintMem {
+		PrintMemUsage()
+	}
 	os.Exit(0)
 }