Make easier to embed in LinuxKit

Split out util file in same way.

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

cmd/moby/build.go

@@ -9,7 +9,6 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 
 	"github.com/moby/tool/src/moby"
@@ -32,27 +31,6 @@ func (f *formatList) Set(value string) error {
 	return nil
 }
 
-// Parse a string which is either a number in MB, or a number with
-// either M (for Megabytes) or G (for GigaBytes) as a suffix and
-// returns the number in MB. Return 0 if string is empty.
-func getDiskSizeMB(s string) (int, error) {
-	if s == "" {
-		return 0, nil
-	}
-	sz := len(s)
-	if strings.HasSuffix(s, "G") {
-		i, err := strconv.Atoi(s[:sz-1])
-		if err != nil {
-			return 0, err
-		}
-		return i * 1024, nil
-	}
-	if strings.HasSuffix(s, "M") {
-		s = s[:sz-1]
-	}
-	return strconv.Atoi(s)
-}
-
 // Process the build arguments and execute build
 func build(args []string) {
 	var buildFormats formatList

cmd/moby/util.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"strconv"
+	"strings"
+)
+
+// This function parses the "size" parameter of a disk specification
+// and returns the size in MB. The "size" parameter defaults to GB, but
+// the unit can be explicitly set with either a G (for GB) or M (for
+// MB). It returns the disk size in MB.
+func getDiskSizeMB(s string) (int, error) {
+	if s == "" {
+		return 0, nil
+	}
+	sz := len(s)
+	if strings.HasSuffix(s, "M") {
+		return strconv.Atoi(s[:sz-1])
+	}
+	if strings.HasSuffix(s, "G") {
+		s = s[:sz-1]
+	}
+
+	i, err := strconv.Atoi(s)
+	if err != nil {
+		return 0, err
+	}
+	return 1024 * i, nil
+}