CellIDFromString: Remove no-op byte < 0 check

jmr · jmr · commit 070ebca06c79 · 2025-03-19T12:19:52.000+01:00
diff --git a/s2/cellid.go b/s2/cellid.go
@@ -355,8 +355,9 @@ func CellIDFromString(s string) CellID {
 	}
 	id := CellIDFromFace(face)
 	for i := 2; i < len(s); i++ {
-		childPos := s[i] - '0'
-		if childPos < 0 || childPos > 3 {
+		var childPos byte = s[i] - '0'
+		// Bytes are non-negative.
+		if childPos > 3 {
 			return CellID(0)
 		}
 		id = id.Children()[childPos]

Original file line number	Diff line number	Diff line change
`@@ -355,8 +355,9 @@ func CellIDFromString(s string) CellID {`
`355`	`355`	`}`
`356`	`356`	`id := CellIDFromFace(face)`
`357`	`357`	`for i := 2; i < len(s); i++ {`
`358`		`- childPos := s[i] - '0'`
`359`		`- if childPos < 0 \|\| childPos > 3 {`
	`358`	`+ var childPos byte = s[i] - '0'`
	`359`	`+ // Bytes are non-negative.`
	`360`	`+ if childPos > 3 {`
`360`	`361`	`return CellID(0)`
`361`	`362`	`}`
`362`	`363`	`id = id.Children()[childPos]`