From dce3bca200ae499e1cf57994c7592a42f66694d5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felix=20Geisendo=CC=88rfer?= <felix@debuggable.com>
Date: Sun, 11 Jan 2015 16:55:26 +0100
Subject: [PATCH] optimize: remove printf for hex encoding

~208 ns/op now
---
 xxd.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xxd.go b/xxd.go
index 1d8ad24..d9e17f8 100644
--- a/xxd.go
+++ b/xxd.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"os"
@@ -48,7 +49,7 @@ func XXD(r io.Reader, w io.Writer) error {
 
 		// Hex values
 		for i := 0; i < n; i++ {
-			fmt.Fprintf(w, "%02x", buf[i])
+			io.WriteString(w, hex.EncodeToString(buf[i:i+1]))
 
 			if i%2 == 1 {
 				io.WriteString(w, " ")