Split strings explicitly in ParseNodeID and ParseEndpointNodeID to sa…

…ve allocations

These routines are called a lot, so this change reduces garbage collection

report/id.go

@@ -200,22 +200,25 @@ func ParseOverlayNodeID(id string) (overlayPrefix string, peerName string) {
 // ParseNodeID produces the host ID and remainder (typically an address) from
 // a node ID. Note that hostID may be blank.
 func ParseNodeID(nodeID string) (hostID string, remainder string, ok bool) {
-	fields := strings.SplitN(nodeID, ScopeDelim, 2)
-	if len(fields) != 2 {
+	first := strings.Index(nodeID, ScopeDelim)
+	if first == -1 {
 		return "", "", false
 	}
-	return fields[0], fields[1], true
+	return nodeID[:first], nodeID[first+1:], true
 }
 
 // ParseEndpointNodeID produces the scope, address, and port and remainder.
-// Note that hostID may be blank.
+// Note that scope may be blank.
 func ParseEndpointNodeID(endpointNodeID string) (scope, address, port string, ok bool) {
-	fields := strings.SplitN(endpointNodeID, ScopeDelim, 3)
-	if len(fields) != 3 {
+	first := strings.Index(endpointNodeID, ScopeDelim)
+	if first == -1 {
 		return "", "", "", false
 	}
-
-	return fields[0], fields[1], fields[2], true
+	second := strings.Index(endpointNodeID[first+1:], ScopeDelim)
+	if second == -1 {
+		return "", "", "", false
+	}
+	return endpointNodeID[:first], endpointNodeID[first+1 : first+1+second], endpointNodeID[first+1+second+1:], true
 }
 
 // ParseAddressNodeID produces the host ID, address from an address node ID.