net,vweb: reduce allocations by ~80%

vlib/net/http/util.v

@@ -0,0 +1,16 @@
+// Copyright (c) 2019-2023 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module http
+
+// A fast version that avoids allocations in s.split()
+// returns the locations of the 2 spaces
+// "GET / HTTP/1.1" => ["GET" "/" "HTTP/1.1"]
+fn fast_request_words(line string) (int, int) {
+	space1 := line.index(' ') or { return 0, 0 }
+	space2 := line.index_after(' ', space1 + 1)
+	if space2 == -1 {
+		return 0, 0
+	}
+	return space1, space2
+}