package strmatcher import ( "math/bits" "regexp" "sort" "strings" "unsafe" ) // PrimeRK is the prime base used in Rabin-Karp algorithm. const PrimeRK = 16777619 // calculate the rolling murmurHash of given string func RollingHash(s string) uint32 { h := uint32(0) for i := len(s) - 1; i >= 0; i-- { h = h*PrimeRK + uint32(s[i]) } return h } // A MphMatcherGroup is divided into three parts: // 1. `full` and `domain` patterns are matched by Rabin-Karp algorithm and minimal perfect hash table; // 2. `substr` patterns are matched by ac automaton; // 3. `regex` patterns are matched with the regex library. type MphMatcherGroup struct { ac *ACAutomaton otherMatchers []matcherEntry rules []string level0 []uint32 level0Mask int level1 []uint32 level1Mask int count uint32 ruleMap *map[string]uint32 } func (g *MphMatcherGroup) AddFullOrDomainPattern(pattern string, t Type) { h := RollingHash(pattern) switch t { case Domain: (*g.ruleMap)["."+pattern] = h*PrimeRK + uint32('.') fallthrough case Full: (*g.ruleMap)[pattern] = h default: } } func NewMphMatcherGroup() *MphMatcherGroup { return &MphMatcherGroup{ ac: nil, otherMatchers: nil, rules: nil, level0: nil, level0Mask: 0, level1: nil, level1Mask: 0, count: 1, ruleMap: &map[string]uint32{}, } } // AddPattern adds a pattern to MphMatcherGroup func (g *MphMatcherGroup) AddPattern(pattern string, t Type) (uint32, error) { switch t { case Substr: if g.ac == nil { g.ac = NewACAutomaton() } g.ac.Add(pattern, t) case Full, Domain: pattern = strings.ToLower(pattern) g.AddFullOrDomainPattern(pattern, t) case Regex: r, err := regexp.Compile(pattern) if err != nil { return 0, err } g.otherMatchers = append(g.otherMatchers, matcherEntry{ m: ®exMatcher{pattern: r}, id: g.count, }) default: panic("Unknown type") } return g.count, nil } // Build builds a minimal perfect hash table and ac automaton from insert rules func (g *MphMatcherGroup) Build() { if g.ac != nil { g.ac.Build() } keyLen := len(*g.ruleMap) if keyLen == 0 { keyLen = 1 (*g.ruleMap)["empty___"] = RollingHash("empty___") } g.level0 = make([]uint32, nextPow2(keyLen/4)) g.level0Mask = len(g.level0) - 1 g.level1 = make([]uint32, nextPow2(keyLen)) g.level1Mask = len(g.level1) - 1 sparseBuckets := make([][]int, len(g.level0)) var ruleIdx int for rule, hash := range *g.ruleMap { n := int(hash) & g.level0Mask g.rules = append(g.rules, rule) sparseBuckets[n] = append(sparseBuckets[n], ruleIdx) ruleIdx++ } g.ruleMap = nil var buckets []indexBucket for n, vals := range sparseBuckets { if len(vals) > 0 { buckets = append(buckets, indexBucket{n, vals}) } } sort.Sort(bySize(buckets)) occ := make([]bool, len(g.level1)) var tmpOcc []int for _, bucket := range buckets { seed := uint32(0) for { findSeed := true tmpOcc = tmpOcc[:0] for _, i := range bucket.vals { n := int(strhashFallback(unsafe.Pointer(&g.rules[i]), uintptr(seed))) & g.level1Mask if occ[n] { for _, n := range tmpOcc { occ[n] = false } seed++ findSeed = false break } occ[n] = true tmpOcc = append(tmpOcc, n) g.level1[n] = uint32(i) } if findSeed { g.level0[bucket.n] = seed break } } } } func nextPow2(v int) int { if v <= 1 { return 1 } const MaxUInt = ^uint(0) n := (MaxUInt >> bits.LeadingZeros(uint(v))) + 1 return int(n) } // Lookup searches for s in t and returns its index and whether it was found. func (g *MphMatcherGroup) Lookup(h uint32, s string) bool { i0 := int(h) & g.level0Mask seed := g.level0[i0] i1 := int(strhashFallback(unsafe.Pointer(&s), uintptr(seed))) & g.level1Mask n := g.level1[i1] return s == g.rules[int(n)] } // Match implements IndexMatcher.Match. func (g *MphMatcherGroup) Match(pattern string) []uint32 { result := []uint32{} hash := uint32(0) for i := len(pattern) - 1; i >= 0; i-- { hash = hash*PrimeRK + uint32(pattern[i]) if pattern[i] == '.' { if g.Lookup(hash, pattern[i:]) { result = append(result, 1) return result } } } if g.Lookup(hash, pattern) { result = append(result, 1) return result } if g.ac != nil && g.ac.Match(pattern) { result = append(result, 1) return result } for _, e := range g.otherMatchers { if e.m.Match(pattern) { result = append(result, e.id) return result } } return nil } type indexBucket struct { n int vals []int } type bySize []indexBucket func (s bySize) Len() int { return len(s) } func (s bySize) Less(i, j int) bool { return len(s[i].vals) > len(s[j].vals) } func (s bySize) Swap(i, j int) { s[i], s[j] = s[j], s[i] } type stringStruct struct { str unsafe.Pointer len int } func strhashFallback(a unsafe.Pointer, h uintptr) uintptr { x := (*stringStruct)(a) return memhashFallback(x.str, h, uintptr(x.len)) } const ( // Constants for multiplication: four random odd 64-bit numbers. m1 = 16877499708836156737 m2 = 2820277070424839065 m3 = 9497967016996688599 m4 = 15839092249703872147 ) var hashkey = [4]uintptr{1, 1, 1, 1} func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr { h := uint64(seed + s*hashkey[0]) tail: switch { case s == 0: case s < 4: h ^= uint64(*(*byte)(p)) h ^= uint64(*(*byte)(unsafe.Add(p, s>>1))) << 8 h ^= uint64(*(*byte)(unsafe.Add(p, s-1))) << 16 h = bits.RotateLeft64(h*m1, 31) * m2 case s <= 8: h ^= uint64(readUnaligned32(p)) h ^= uint64(readUnaligned32(unsafe.Add(p, s-4))) << 32 h = bits.RotateLeft64(h*m1, 31) * m2 case s <= 16: h ^= readUnaligned64(p) h = bits.RotateLeft64(h*m1, 31) * m2 h ^= readUnaligned64(unsafe.Add(p, s-8)) h = bits.RotateLeft64(h*m1, 31) * m2 case s <= 32: h ^= readUnaligned64(p) h = bits.RotateLeft64(h*m1, 31) * m2 h ^= readUnaligned64(unsafe.Add(p, 8)) h = bits.RotateLeft64(h*m1, 31) * m2 h ^= readUnaligned64(unsafe.Add(p, s-16)) h = bits.RotateLeft64(h*m1, 31) * m2 h ^= readUnaligned64(unsafe.Add(p, s-8)) h = bits.RotateLeft64(h*m1, 31) * m2 default: v1 := h v2 := uint64(seed * hashkey[1]) v3 := uint64(seed * hashkey[2]) v4 := uint64(seed * hashkey[3]) for s >= 32 { v1 ^= readUnaligned64(p) v1 = bits.RotateLeft64(v1*m1, 31) * m2 p = unsafe.Add(p, 8) v2 ^= readUnaligned64(p) v2 = bits.RotateLeft64(v2*m2, 31) * m3 p = unsafe.Add(p, 8) v3 ^= readUnaligned64(p) v3 = bits.RotateLeft64(v3*m3, 31) * m4 p = unsafe.Add(p, 8) v4 ^= readUnaligned64(p) v4 = bits.RotateLeft64(v4*m4, 31) * m1 p = unsafe.Add(p, 8) s -= 32 } h = v1 ^ v2 ^ v3 ^ v4 goto tail } h ^= h >> 29 h *= m3 h ^= h >> 32 return uintptr(h) } func readUnaligned32(p unsafe.Pointer) uint32 { q := (*[4]byte)(p) return uint32(q[0]) | uint32(q[1])<<8 | uint32(q[2])<<16 | uint32(q[3])<<24 } func readUnaligned64(p unsafe.Pointer) uint64 { q := (*[8]byte)(p) return uint64(q[0]) | uint64(q[1])<<8 | uint64(q[2])<<16 | uint64(q[3])<<24 | uint64(q[4])<<32 | uint64(q[5])<<40 | uint64(q[6])<<48 | uint64(q[7])<<56 }