From 7d13447b64506ea07c912691b1ed1624c52f87ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1s=20Senart?= <tomas@soundcloud.com>
Date: Fri, 16 Aug 2013 19:38:57 +0200
Subject: [PATCH] Simplify random ordering code

---
 main.go    |  7 +++----
 targets.go | 14 ++++++--------
 2 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/main.go b/main.go
index 51fc45e..876e11a 100644
--- a/main.go
+++ b/main.go
@@ -4,7 +4,6 @@ import (
 	"flag"
 	"io"
 	"log"
-	"math/rand"
 	"net/http"
 	"os"
 	"runtime"
@@ -42,7 +41,7 @@ func main() {
 
 	switch *ordering {
 	case "random":
-		rand.Seed(time.Now().UnixNano())
+		targets.Shuffle(time.Now().UnixNano())
 	case "sequential":
 		break
 	default:
@@ -92,8 +91,8 @@ func attack(targets Targets, ordering string, rate uint, duration time.Duration,
 	defer close(responses)
 	client := NewClient(rate)
 	go client.Drill(hits, responses) // Attack!
-	for i, idxs := 0, targets.Iter(ordering); i < cap(hits); i++ {
-		hits <- targets[idxs[i%len(idxs)]]
+	for i := 0; i < cap(hits); i++ {
+		hits <- targets[i%len(targets)]
 	}
 	// Wait for all requests to finish
 	for i := 0; i < cap(responses); i++ {
diff --git a/targets.go b/targets.go
index 07d219e..f97cec9 100644
--- a/targets.go
+++ b/targets.go
@@ -49,13 +49,11 @@ func NewTargets(source io.Reader) (Targets, error) {
 	return targets, nil
 }
 
-func (t Targets) Iter(ordering string) []int {
-	if ordering == "random" {
-		return rand.Perm(len(t))
+func (t Targets) Shuffle(seed int64) {
+	rand.Seed(seed)
+	for i, rnd := range rand.Perm(len(t)) {
+		tmp := t[i]
+		t[i] = t[rnd]
+		t[rnd] = tmp
 	}
-	iter := make([]int, len(t))
-	for i := 0; i < len(t); i++ {
-		iter[i] = i
-	}
-	return iter
 }