提升WAF正则表达式性能（提升20%以上）

internal/re/rune_tree.go

@@ -0,0 +1,74 @@
+// Copyright 2022 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
+
+package re
+
+type RuneMap map[rune]*RuneTree
+
+func (this *RuneMap) Lookup(s string, caseInsensitive bool) bool {
+	return this.lookup([]rune(s), caseInsensitive, 0)
+}
+
+func (this RuneMap) lookup(runes []rune, caseInsensitive bool, depth int) bool {
+	if len(runes) == 0 {
+		return false
+	}
+	for i, r := range runes {
+		tree, ok := this[r]
+		if !ok {
+			if caseInsensitive {
+				if r >= 'a' && r <= 'z' {
+					r -= 32
+					tree, ok = this[r]
+				} else if r >= 'A' && r <= 'Z' {
+					r += 32
+					tree, ok = this[r]
+				}
+			}
+			if !ok {
+				if depth > 0 {
+					return false
+				}
+				continue
+			}
+		}
+		if tree.IsEnd {
+			return true
+		}
+		b := tree.Children.lookup(runes[i+1:], caseInsensitive, depth+1)
+		if b {
+			return true
+		}
+	}
+	return false
+}
+
+type RuneTree struct {
+	Children RuneMap
+	IsEnd    bool
+}
+
+func NewRuneTree(list []string) RuneMap {
+	var rootMap = RuneMap{}
+	for _, s := range list {
+		if len(s) == 0 {
+			continue
+		}
+
+		var lastMap = rootMap
+		var runes = []rune(s)
+		for index, r := range runes {
+			tree, ok := lastMap[r]
+			if !ok {
+				tree = &RuneTree{
+					Children: RuneMap{},
+				}
+				lastMap[r] = tree
+			}
+			if index == len(runes)-1 {
+				tree.IsEnd = true
+			}
+			lastMap = tree.Children
+		}
+	}
+	return rootMap
+}