use more efficient item type parsing for files

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

gopher/itemtype.go

@@ -1,6 +1,9 @@
 package gopher
 
-import "strings"
+import (
+	"path"
+	"strings"
+)
 
 // ItemType specifies a gopher item type char
 type ItemType byte
@@ -134,30 +137,25 @@ var fileExtMap = map[string]ItemType{
 
 // getItemType is an internal function to get an ItemType for a file name string
 func getItemType(name string) ItemType {
-	// Split, name MUST be lower
-	split := strings.Split(strings.ToLower(name), ".")
-
-	// First we look at how many '.' in name string
-	splitLen := len(split)
-	switch splitLen {
-	case 0:
-		// We cannot tell the file type, return default
+	// Get file extension (lower!)
+	ext := strings.ToLower(path.Ext(name))
+
+	// Empty, cannot tell so return default
+	if ext == "" {
 		return typeDefault
+	}
 
-	default:
-		// get index of str after last '.', look up in fileExtMap
-		fileType, ok := fileExtMap["."+split[splitLen-1]]
-		if ok {
-			return fileType
-		}
+	// Lookup in map, return value or default
+	itemType, ok := fileExtMap["."+ext]
+	if !ok {
 		return typeDefault
 	}
+	return itemType
 }
 
 // parseLineType parses a gophermap's line type based on first char and contents
 func parseLineType(line string) ItemType {
 	lineLen := len(line)
-
 	if lineLen == 0 {
 		return typeInfoNotStated
 	}