dices.go: make Roll() more robust

1 files changed, 8 insertions, 3 deletions

diff --git a/logic/dices.go b/logic/dices.go
index 07c4a98..43dca22 100644
--- a/logic/dices.go
+++ b/logic/dices.go
@@ -1,6 +1,7 @@
 package logic
 
 import (
+	"errors"
 	"fmt"
 	"math/rand"
 	"sort"
@@ -10,14 +11,18 @@ var diceRunes = [7]string{"", "\u2680", "\u2681", "\u2682", "\u2683", "\u2684",
 
 type Dices [5]int
 
-func (d *Dices) Roll(i []int) {
-	if i == nil {
-		i = []int{1,2,3,4,5}
+func (d *Dices) Roll(i []int) error {
+	if i == nil || len(i) == 0 {
+		i = []int{1, 2, 3, 4, 5}
 	}
 	for _, v := range i {
+		if v > 6 || v < 1 {
+			return errors.New("index out of range")
+		}
 		d[v-1] = rand.Int()%6 + 1
 	}
 	sort.Ints(d[0:])
+	return nil
 }
 
 func (d Dices) String() string {