make sure charset does not contain duplicates

quackduck · quackduck · commit 206c625c7cf2 · 2022-11-24T13:35:03.000-08:00
diff --git a/aces.go b/aces.go
@@ -125,6 +125,13 @@ func NewCoding(charset []rune) (*Coding, error) {
 				"\n   want: a power of 2 (nearest is", 1<<numOfBits, "which is", math.Abs(float64(len(charset)-1<<numOfBits)), "away)"),
 		)
 	}
+	seen := make(map[rune]bool)
+	for _, r := range charset {
+		if seen[r] {
+			return nil, errors.New("charset contains duplicates")
+		}
+		seen[r] = true
+	}
 	return &Coding{charset: charset, numOfBits: numOfBits}, nil
 }
 

Original file line number	Diff line number	Diff line change
`@@ -125,6 +125,13 @@ func NewCoding(charset []rune) (*Coding, error) {`
`125`	`125`	`"\n want: a power of 2 (nearest is", 1<<numOfBits, "which is", math.Abs(float64(len(charset)-1<<numOfBits)), "away)"),`
`126`	`126`	`)`
`127`	`127`	`}`
	`128`	`+ seen := make(map[rune]bool)`
	`129`	`+ for _, r := range charset {`
	`130`	`+ if seen[r] {`
	`131`	`+ return nil, errors.New("charset contains duplicates")`
	`132`	`+ }`
	`133`	`+ seen[r] = true`
	`134`	`+ }`
`128`	`135`	`return &Coding{charset: charset, numOfBits: numOfBits}, nil`
`129`	`136`	`}`
`130`	`137`