mirror of
https://github.com/golang/go
synced 2024-11-23 08:20:05 -07:00
regexp: add one-pass optimization from RE2
This produces about a 2.3x speedup for patterns that can be handled this way. LGTM=rsc R=rsc CC=golang-codereviews https://golang.org/cl/13345046
This commit is contained in:
David Covert
Russ Cox
parent
84570aa9a1
commit
76236ef136
@ -578,3 +578,58 @@ func BenchmarkAnchoredLongMatch(b *testing.B) {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkOnePassShortA(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcddddddeeeededd")
|
||||
re := MustCompile("^.bc(d|e)*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
func BenchmarkNotOnePassShortA(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcddddddeeeededd")
|
||||
re := MustCompile(".bc(d|e)*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
func BenchmarkOnePassShortB(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcddddddeeeededd")
|
||||
re := MustCompile("^.bc(?:d|e)*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
func BenchmarkNotOnePassShortB(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcddddddeeeededd")
|
||||
re := MustCompile(".bc(?:d|e)*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
func BenchmarkOnePassLongPrefix(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcdefghijklmnopqrstuvwxyz")
|
||||
re := MustCompile("^abcdefghijklmnopqrstuvwxyz.*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
func BenchmarkOnePassLongNotPrefix(b *testing.B) {
|
||||
b.StopTimer()
|
||||
x := []byte("abcdefghijklmnopqrstuvwxyz")
|
||||
re := MustCompile("^.bcdefghijklmnopqrstuvwxyz.*$")
|
||||
b.StartTimer()
|
||||
for i := 0; i < b.N; i++ {
|
||||
re.Match(x)
|
||||
}
|
||||
}
|
||||
|
||||
@ -37,6 +37,7 @@ type thread struct {
|
||||
type machine struct {
|
||||
re *Regexp // corresponding Regexp
|
||||
p *syntax.Prog // compiled program
|
||||
op *syntax.Prog // compiled onepass program, or syntax.NotOnePass
|
||||
q0, q1 queue // two queues for runq, nextq
|
||||
pool []*thread // pool of available threads
|
||||
matched bool // whether a match was found
|
||||
@ -66,8 +67,8 @@ func (m *machine) newInputReader(r io.RuneReader) input {
|
||||
}
|
||||
|
||||
// progMachine returns a new machine running the prog p.
|
||||
func progMachine(p *syntax.Prog) *machine {
|
||||
m := &machine{p: p}
|
||||
func progMachine(p, op *syntax.Prog) *machine {
|
||||
m := &machine{p: p, op: op}
|
||||
n := len(m.p.Inst)
|
||||
m.q0 = queue{make([]uint32, n), make([]entry, 0, n)}
|
||||
m.q1 = queue{make([]uint32, n), make([]entry, 0, n)}
|
||||
@ -312,6 +313,105 @@ func (m *machine) add(q *queue, pc uint32, pos int, cap []int, cond syntax.Empty
|
||||
return t
|
||||
}
|
||||
|
||||
// onepass runs the machine over the input starting at pos.
|
||||
// It reports whether a match was found.
|
||||
// If so, m.matchcap holds the submatch information.
|
||||
func (m *machine) onepass(i input, pos int) bool {
|
||||
startCond := m.re.cond
|
||||
if startCond == ^syntax.EmptyOp(0) { // impossible
|
||||
return false
|
||||
}
|
||||
m.matched = false
|
||||
for i := range m.matchcap {
|
||||
m.matchcap[i] = -1
|
||||
}
|
||||
r, r1 := endOfText, endOfText
|
||||
width, width1 := 0, 0
|
||||
r, width = i.step(pos)
|
||||
if r != endOfText {
|
||||
r1, width1 = i.step(pos + width)
|
||||
}
|
||||
var flag syntax.EmptyOp
|
||||
if pos == 0 {
|
||||
flag = syntax.EmptyOpContext(-1, r)
|
||||
} else {
|
||||
flag = i.context(pos)
|
||||
}
|
||||
pc := m.op.Start
|
||||
inst := m.op.Inst[pc]
|
||||
// If there is a simple literal prefix, skip over it.
|
||||
if pos == 0 && syntax.EmptyOp(inst.Arg)&^flag == 0 &&
|
||||
len(m.re.prefix) > 0 && i.canCheckPrefix() {
|
||||
// Match requires literal prefix; fast search for it.
|
||||
if i.hasPrefix(m.re) {
|
||||
pos += len(m.re.prefix)
|
||||
r, width = i.step(pos)
|
||||
r1, width1 = i.step(pos + width)
|
||||
flag = i.context(pos)
|
||||
pc = int(m.re.prefixEnd)
|
||||
} else {
|
||||
return m.matched
|
||||
}
|
||||
}
|
||||
for {
|
||||
inst = m.op.Inst[pc]
|
||||
pc = int(inst.Out)
|
||||
switch inst.Op {
|
||||
default:
|
||||
panic("bad inst")
|
||||
case syntax.InstMatch:
|
||||
m.matched = true
|
||||
if len(m.matchcap) > 0 {
|
||||
m.matchcap[0] = 0
|
||||
m.matchcap[1] = pos
|
||||
}
|
||||
return m.matched
|
||||
case syntax.InstRune:
|
||||
if !inst.MatchRune(r) {
|
||||
return m.matched
|
||||
}
|
||||
case syntax.InstRune1:
|
||||
if r != inst.Rune[0] {
|
||||
return m.matched
|
||||
}
|
||||
case syntax.InstRuneAny:
|
||||
// Nothing
|
||||
case syntax.InstRuneAnyNotNL:
|
||||
if r == '\n' {
|
||||
return m.matched
|
||||
}
|
||||
// peek at the input rune to see which branch of the Alt to take
|
||||
case syntax.InstAlt, syntax.InstAltMatch:
|
||||
pc = int(inst.OnePassNext(r))
|
||||
continue
|
||||
case syntax.InstFail:
|
||||
return m.matched
|
||||
case syntax.InstNop:
|
||||
continue
|
||||
case syntax.InstEmptyWidth:
|
||||
if syntax.EmptyOp(inst.Arg)&^flag != 0 {
|
||||
return m.matched
|
||||
}
|
||||
continue
|
||||
case syntax.InstCapture:
|
||||
if int(inst.Arg) < len(m.matchcap) {
|
||||
m.matchcap[inst.Arg] = pos
|
||||
}
|
||||
continue
|
||||
}
|
||||
if width == 0 {
|
||||
break
|
||||
}
|
||||
flag = syntax.EmptyOpContext(r, r1)
|
||||
pos += width
|
||||
r, width = r1, width1
|
||||
if r != endOfText {
|
||||
r1, width1 = i.step(pos + width)
|
||||
}
|
||||
}
|
||||
return m.matched
|
||||
}
|
||||
|
||||
// empty is a non-nil 0-element slice,
|
||||
// so doExecute can avoid an allocation
|
||||
// when 0 captures are requested from a successful match.
|
||||
@ -329,16 +429,23 @@ func (re *Regexp) doExecute(r io.RuneReader, b []byte, s string, pos int, ncap i
|
||||
} else {
|
||||
i = m.newInputString(s)
|
||||
}
|
||||
m.init(ncap)
|
||||
if !m.match(i, pos) {
|
||||
re.put(m)
|
||||
return nil
|
||||
if m.op != syntax.NotOnePass {
|
||||
if !m.onepass(i, pos) {
|
||||
re.put(m)
|
||||
return nil
|
||||
}
|
||||
} else {
|
||||
m.init(ncap)
|
||||
if !m.match(i, pos) {
|
||||
re.put(m)
|
||||
return nil
|
||||
}
|
||||
}
|
||||
if ncap == 0 {
|
||||
re.put(m)
|
||||
return empty // empty but not nil
|
||||
}
|
||||
cap := make([]int, ncap)
|
||||
cap := make([]int, len(m.matchcap))
|
||||
copy(cap, m.matchcap)
|
||||
re.put(m)
|
||||
return cap
|
||||
|
||||
@ -75,10 +75,12 @@ type Regexp struct {
|
||||
// read-only after Compile
|
||||
expr string // as passed to Compile
|
||||
prog *syntax.Prog // compiled program
|
||||
onepass *syntax.Prog // onpass program or nil
|
||||
prefix string // required prefix in unanchored matches
|
||||
prefixBytes []byte // prefix, as a []byte
|
||||
prefixComplete bool // prefix is the entire regexp
|
||||
prefixRune rune // first rune in prefix
|
||||
prefixEnd uint32 // pc for last rune in prefix
|
||||
cond syntax.EmptyOp // empty-width conditions required at start of match
|
||||
numSubexp int
|
||||
subexpNames []string
|
||||
@ -155,12 +157,17 @@ func compile(expr string, mode syntax.Flags, longest bool) (*Regexp, error) {
|
||||
regexp := &Regexp{
|
||||
expr: expr,
|
||||
prog: prog,
|
||||
onepass: prog.CompileOnePass(),
|
||||
numSubexp: maxCap,
|
||||
subexpNames: capNames,
|
||||
cond: prog.StartCond(),
|
||||
longest: longest,
|
||||
}
|
||||
regexp.prefix, regexp.prefixComplete = prog.Prefix()
|
||||
if regexp.onepass == syntax.NotOnePass {
|
||||
regexp.prefix, regexp.prefixComplete = prog.Prefix()
|
||||
} else {
|
||||
regexp.prefix, regexp.prefixComplete, regexp.prefixEnd = prog.OnePassPrefix()
|
||||
}
|
||||
if regexp.prefix != "" {
|
||||
// TODO(rsc): Remove this allocation by adding
|
||||
// IndexString to package bytes.
|
||||
@ -182,7 +189,7 @@ func (re *Regexp) get() *machine {
|
||||
return z
|
||||
}
|
||||
re.mu.Unlock()
|
||||
z := progMachine(re.prog)
|
||||
z := progMachine(re.prog, re.onepass)
|
||||
z.re = re
|
||||
return z
|
||||
}
|
||||
|
||||
@ -6,6 +6,7 @@ package syntax
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"sort"
|
||||
"strconv"
|
||||
"unicode"
|
||||
)
|
||||
@ -35,8 +36,30 @@ const (
|
||||
InstRune1
|
||||
InstRuneAny
|
||||
InstRuneAnyNotNL
|
||||
InstLast
|
||||
)
|
||||
|
||||
var instOpNames = []string{
|
||||
"InstAlt",
|
||||
"InstAltMatch",
|
||||
"InstCapture",
|
||||
"InstEmptyWidth",
|
||||
"InstMatch",
|
||||
"InstFail",
|
||||
"InstNop",
|
||||
"InstRune",
|
||||
"InstRune1",
|
||||
"InstRuneAny",
|
||||
"InstRuneAnyNotNL",
|
||||
}
|
||||
|
||||
func (i InstOp) String() string {
|
||||
if i >= InstLast {
|
||||
return ""
|
||||
}
|
||||
return instOpNames[i]
|
||||
}
|
||||
|
||||
// An EmptyOp specifies a kind or mixture of zero-width assertions.
|
||||
type EmptyOp uint8
|
||||
|
||||
@ -93,6 +116,7 @@ type Inst struct {
|
||||
Out uint32 // all but InstMatch, InstFail
|
||||
Arg uint32 // InstAlt, InstAltMatch, InstCapture, InstEmptyWidth
|
||||
Rune []rune
|
||||
Next []uint32 // If input rune matches
|
||||
}
|
||||
|
||||
func (p *Prog) String() string {
|
||||
@ -103,13 +127,13 @@ func (p *Prog) String() string {
|
||||
|
||||
// skipNop follows any no-op or capturing instructions
|
||||
// and returns the resulting pc.
|
||||
func (p *Prog) skipNop(pc uint32) *Inst {
|
||||
func (p *Prog) skipNop(pc uint32) (*Inst, uint32) {
|
||||
i := &p.Inst[pc]
|
||||
for i.Op == InstNop || i.Op == InstCapture {
|
||||
pc = i.Out
|
||||
i = &p.Inst[pc]
|
||||
}
|
||||
return i
|
||||
return i, pc
|
||||
}
|
||||
|
||||
// op returns i.Op but merges all the Rune special cases into InstRune
|
||||
@ -126,7 +150,7 @@ func (i *Inst) op() InstOp {
|
||||
// regexp must start with. Complete is true if the prefix
|
||||
// is the entire match.
|
||||
func (p *Prog) Prefix() (prefix string, complete bool) {
|
||||
i := p.skipNop(uint32(p.Start))
|
||||
i, _ := p.skipNop(uint32(p.Start))
|
||||
|
||||
// Avoid allocation of buffer if prefix is empty.
|
||||
if i.op() != InstRune || len(i.Rune) != 1 {
|
||||
@ -137,11 +161,41 @@ func (p *Prog) Prefix() (prefix string, complete bool) {
|
||||
var buf bytes.Buffer
|
||||
for i.op() == InstRune && len(i.Rune) == 1 && Flags(i.Arg)&FoldCase == 0 {
|
||||
buf.WriteRune(i.Rune[0])
|
||||
i = p.skipNop(i.Out)
|
||||
i, _ = p.skipNop(i.Out)
|
||||
}
|
||||
return buf.String(), i.Op == InstMatch
|
||||
}
|
||||
|
||||
// OnePassPrefix returns a literal string that all matches for the
|
||||
// regexp must start with. Complete is true if the prefix
|
||||
// is the entire match. Pc is the index of the last rune instruction
|
||||
// in the string. The OnePassPrefix skips over the mandatory
|
||||
// EmptyBeginText
|
||||
func (p *Prog) OnePassPrefix() (prefix string, complete bool, pc uint32) {
|
||||
i := &p.Inst[p.Start]
|
||||
if i.Op != InstEmptyWidth || (EmptyOp(i.Arg))&EmptyBeginText == 0 {
|
||||
return "", i.Op == InstMatch, uint32(p.Start)
|
||||
}
|
||||
pc = i.Out
|
||||
i = &p.Inst[pc]
|
||||
for i.Op == InstNop {
|
||||
pc = i.Out
|
||||
i = &p.Inst[pc]
|
||||
}
|
||||
// Avoid allocation of buffer if prefix is empty.
|
||||
if i.op() != InstRune || len(i.Rune) != 1 {
|
||||
return "", i.Op == InstMatch, uint32(p.Start)
|
||||
}
|
||||
|
||||
// Have prefix; gather characters.
|
||||
var buf bytes.Buffer
|
||||
for i.op() == InstRune && len(i.Rune) == 1 && Flags(i.Arg)&FoldCase == 0 {
|
||||
buf.WriteRune(i.Rune[0])
|
||||
pc, i = i.Out, &p.Inst[i.Out]
|
||||
}
|
||||
return buf.String(), i.Op == InstEmptyWidth && (EmptyOp(i.Arg))&EmptyBeginText != 0, pc
|
||||
}
|
||||
|
||||
// StartCond returns the leading empty-width conditions that must
|
||||
// be true in any match. It returns ^EmptyOp(0) if no matches are possible.
|
||||
func (p *Prog) StartCond() EmptyOp {
|
||||
@ -166,35 +220,58 @@ Loop:
|
||||
return flag
|
||||
}
|
||||
|
||||
const noMatch = -1
|
||||
|
||||
// OnePassNext selects the next actionable state of the prog, based on the input character.
|
||||
// It should only be called when i.Op == InstAlt or InstAltMatch, and from the one-pass machine.
|
||||
// One of the alternates may ultimately lead without input to end of line. If the instruction
|
||||
// is InstAltMatch the path to the InstMatch is in i.Out, the normal node in i.Next.
|
||||
func (i *Inst) OnePassNext(r rune) uint32 {
|
||||
next := i.MatchRunePos(r)
|
||||
if next != noMatch {
|
||||
return i.Next[next]
|
||||
}
|
||||
if i.Op == InstAltMatch {
|
||||
return i.Out
|
||||
}
|
||||
return 0
|
||||
}
|
||||
|
||||
// MatchRune returns true if the instruction matches (and consumes) r.
|
||||
// It should only be called when i.Op == InstRune.
|
||||
func (i *Inst) MatchRune(r rune) bool {
|
||||
return i.MatchRunePos(r) != noMatch
|
||||
}
|
||||
|
||||
// MatchRunePos returns the index of the rune pair if the instruction matches.
|
||||
// It should only be called when i.Op == InstRune.
|
||||
func (i *Inst) MatchRunePos(r rune) int {
|
||||
rune := i.Rune
|
||||
|
||||
// Special case: single-rune slice is from literal string, not char class.
|
||||
if len(rune) == 1 {
|
||||
r0 := rune[0]
|
||||
if r == r0 {
|
||||
return true
|
||||
return 0
|
||||
}
|
||||
if Flags(i.Arg)&FoldCase != 0 {
|
||||
for r1 := unicode.SimpleFold(r0); r1 != r0; r1 = unicode.SimpleFold(r1) {
|
||||
if r == r1 {
|
||||
return true
|
||||
return 0
|
||||
}
|
||||
}
|
||||
}
|
||||
return false
|
||||
return noMatch
|
||||
}
|
||||
|
||||
// Peek at the first few pairs.
|
||||
// Should handle ASCII well.
|
||||
for j := 0; j < len(rune) && j <= 8; j += 2 {
|
||||
if r < rune[j] {
|
||||
return false
|
||||
return noMatch
|
||||
}
|
||||
if r <= rune[j+1] {
|
||||
return true
|
||||
return j / 2
|
||||
}
|
||||
}
|
||||
|
||||
@ -205,14 +282,14 @@ func (i *Inst) MatchRune(r rune) bool {
|
||||
m := lo + (hi-lo)/2
|
||||
if c := rune[2*m]; c <= r {
|
||||
if r <= rune[2*m+1] {
|
||||
return true
|
||||
return m
|
||||
}
|
||||
lo = m + 1
|
||||
} else {
|
||||
hi = m
|
||||
}
|
||||
}
|
||||
return false
|
||||
return noMatch
|
||||
}
|
||||
|
||||
// As per re2's Prog::IsWordChar. Determines whether rune is an ASCII word char.
|
||||
@ -311,3 +388,491 @@ func dumpInst(b *bytes.Buffer, i *Inst) {
|
||||
bw(b, "anynotnl -> ", u32(i.Out))
|
||||
}
|
||||
}
|
||||
|
||||
// Sparse Array implementation is used as a queue.
|
||||
type queue struct {
|
||||
sparse []uint32
|
||||
dense []uint32
|
||||
size, nextIndex uint32
|
||||
}
|
||||
|
||||
func (q *queue) empty() bool {
|
||||
return q.nextIndex >= q.size
|
||||
}
|
||||
|
||||
func (q *queue) next() (n uint32) {
|
||||
n = q.dense[q.nextIndex]
|
||||
q.nextIndex++
|
||||
return
|
||||
}
|
||||
|
||||
func (q *queue) clear() {
|
||||
q.size = 0
|
||||
q.nextIndex = 0
|
||||
}
|
||||
|
||||
func (q *queue) reset() {
|
||||
q.nextIndex = 0
|
||||
}
|
||||
|
||||
func (q *queue) contains(u uint32) bool {
|
||||
if u >= uint32(len(q.sparse)) {
|
||||
return false
|
||||
}
|
||||
return q.sparse[u] < q.size && q.dense[q.sparse[u]] == u
|
||||
}
|
||||
|
||||
func (q *queue) insert(u uint32) {
|
||||
if !q.contains(u) {
|
||||
q.insertNew(u)
|
||||
}
|
||||
}
|
||||
|
||||
func (q *queue) insertNew(u uint32) {
|
||||
if u >= uint32(len(q.sparse)) {
|
||||
return
|
||||
}
|
||||
q.sparse[u] = q.size
|
||||
q.dense[q.size] = u
|
||||
q.size++
|
||||
}
|
||||
|
||||
func newQueue(size int) (q *queue) {
|
||||
return &queue{
|
||||
sparse: make([]uint32, size),
|
||||
dense: make([]uint32, size),
|
||||
}
|
||||
}
|
||||
|
||||
// mergeRuneSets merges two non-intersecting runesets, and returns the merged result,
|
||||
// and a NextIp array. The idea is that if a rune matches the OnePassRunes at index
|
||||
// i, NextIp[i/2] is the target. If the input sets intersect, an empty runeset and a
|
||||
// NextIp array with the single element mergeFailed is returned.
|
||||
// The code assumes that both inputs contain ordered and non-intersecting rune pairs.
|
||||
const mergeFailed = uint32(0xffffffff)
|
||||
|
||||
var (
|
||||
noRune = []rune{}
|
||||
noNext = []uint32{mergeFailed}
|
||||
)
|
||||
|
||||
func mergeRuneSets(leftRunes, rightRunes *[]rune, leftPC, rightPC uint32) ([]rune, []uint32) {
|
||||
leftLen := len(*leftRunes)
|
||||
rightLen := len(*rightRunes)
|
||||
if leftLen&0x1 != 0 || rightLen&0x1 != 0 {
|
||||
panic("mergeRuneSets odd length []rune")
|
||||
}
|
||||
var (
|
||||
lx, rx int
|
||||
)
|
||||
merged := make([]rune, 0)
|
||||
next := make([]uint32, 0)
|
||||
ok := true
|
||||
defer func() {
|
||||
if !ok {
|
||||
merged = nil
|
||||
next = nil
|
||||
}
|
||||
}()
|
||||
|
||||
ix := -1
|
||||
extend := func(newLow *int, newArray *[]rune, pc uint32) bool {
|
||||
if ix > 0 && (*newArray)[*newLow] <= merged[ix] {
|
||||
return false
|
||||
}
|
||||
merged = append(merged, (*newArray)[*newLow], (*newArray)[*newLow+1])
|
||||
*newLow += 2
|
||||
ix += 2
|
||||
next = append(next, pc)
|
||||
return true
|
||||
}
|
||||
|
||||
for lx < leftLen || rx < rightLen {
|
||||
switch {
|
||||
case rx >= rightLen:
|
||||
ok = extend(&lx, leftRunes, leftPC)
|
||||
case lx >= leftLen:
|
||||
ok = extend(&rx, rightRunes, rightPC)
|
||||
case (*rightRunes)[rx] < (*leftRunes)[lx]:
|
||||
ok = extend(&rx, rightRunes, rightPC)
|
||||
default:
|
||||
ok = extend(&lx, leftRunes, leftPC)
|
||||
}
|
||||
if !ok {
|
||||
return noRune, noNext
|
||||
}
|
||||
}
|
||||
return merged, next
|
||||
}
|
||||
|
||||
// cleanupOnePass drops working memory, and restores certain shortcut instructions.
|
||||
func (prog *Prog) cleanupOnePass(pOriginal *Prog) {
|
||||
for ix, instOriginal := range pOriginal.Inst {
|
||||
switch instOriginal.Op {
|
||||
case InstAlt, InstAltMatch, InstRune:
|
||||
case InstCapture, InstEmptyWidth, InstNop, InstMatch, InstFail:
|
||||
prog.Inst[ix].Next = nil
|
||||
case InstRune1, InstRuneAny, InstRuneAnyNotNL:
|
||||
prog.Inst[ix].Next = nil
|
||||
prog.Inst[ix] = instOriginal
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// onePassCopy creates a copy of the original Prog, as we'll be modifying it
|
||||
func (prog *Prog) onePassCopy() *Prog {
|
||||
p := &Prog{
|
||||
Inst: append([]Inst{}[:], prog.Inst...),
|
||||
Start: prog.Start,
|
||||
NumCap: prog.NumCap,
|
||||
}
|
||||
for _, inst := range p.Inst {
|
||||
inst.Next = make([]uint32, 0)
|
||||
}
|
||||
|
||||
// rewrites one or more common Prog constructs that enable some otherwise
|
||||
// non-onepass Progs to be onepass. A:BD (for example) means an InstAlt at
|
||||
// ip A, that points to ips B & C.
|
||||
// A:BC + B:DA => A:BC + B:CD
|
||||
// A:BC + B:DC => A:DC + B:DC
|
||||
for pc := range p.Inst {
|
||||
switch p.Inst[pc].Op {
|
||||
default:
|
||||
continue
|
||||
case InstAlt, InstAltMatch:
|
||||
// A:Bx + B:Ay
|
||||
p_A_Other := &p.Inst[pc].Out
|
||||
p_A_Alt := &p.Inst[pc].Arg
|
||||
// make sure a target is another Alt
|
||||
instAlt := p.Inst[*p_A_Alt]
|
||||
if !(instAlt.Op == InstAlt || instAlt.Op == InstAltMatch) {
|
||||
p_A_Alt, p_A_Other = p_A_Other, p_A_Alt
|
||||
instAlt = p.Inst[*p_A_Alt]
|
||||
if !(instAlt.Op == InstAlt || instAlt.Op == InstAltMatch) {
|
||||
continue
|
||||
}
|
||||
}
|
||||
instOther := p.Inst[*p_A_Other]
|
||||
// Analyzing both legs pointing to Alts is for another day
|
||||
if instOther.Op == InstAlt || instOther.Op == InstAltMatch {
|
||||
// too complicated
|
||||
continue
|
||||
}
|
||||
// simple empty transition loop
|
||||
// A:BC + B:DA => A:BC + B:DC
|
||||
p_B_Alt := &p.Inst[*p_A_Alt].Out
|
||||
p_B_Other := &p.Inst[*p_A_Alt].Arg
|
||||
patch := false
|
||||
if instAlt.Out == uint32(pc) {
|
||||
patch = true
|
||||
} else if instAlt.Arg == uint32(pc) {
|
||||
patch = true
|
||||
p_B_Alt, p_B_Other = p_B_Other, p_B_Alt
|
||||
}
|
||||
if patch {
|
||||
*p_B_Alt = *p_A_Other
|
||||
}
|
||||
|
||||
// empty transition to common target
|
||||
// A:BC + B:DC => A:DC + B:DC
|
||||
if *p_A_Other == *p_B_Alt {
|
||||
*p_A_Alt = *p_B_Other
|
||||
}
|
||||
}
|
||||
}
|
||||
return p
|
||||
}
|
||||
|
||||
// runeSlice exists to permit sorting the case-folded rune sets.
|
||||
type runeSlice []rune
|
||||
|
||||
func (p runeSlice) Len() int { return len(p) }
|
||||
func (p runeSlice) Less(i, j int) bool { return p[i] < p[j] }
|
||||
func (p runeSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
|
||||
|
||||
// Sort is a convenience method.
|
||||
func (p runeSlice) Sort() {
|
||||
sort.Sort(p)
|
||||
}
|
||||
|
||||
// makeOnePass creates a onepass Prog, if possible. It is possible if at any alt,
|
||||
// the match engine can always tell which branch to take. The routine may modify
|
||||
// p if it is turned into a onepass Prog. If it isn't possible for this to be a
|
||||
// onepass Prog, the Prog syntax.NotOnePass is returned. makeOnePass is resursive
|
||||
// to the size of the Prog
|
||||
func (p *Prog) makeOnePass() *Prog {
|
||||
var (
|
||||
instQueue = newQueue(len(p.Inst))
|
||||
visitQueue = newQueue(len(p.Inst))
|
||||
build func(uint32, *queue)
|
||||
check func(uint32, map[uint32]bool) bool
|
||||
onePassRunes = make([][]rune, len(p.Inst))
|
||||
)
|
||||
build = func(pc uint32, q *queue) {
|
||||
if q.contains(pc) {
|
||||
return
|
||||
}
|
||||
inst := p.Inst[pc]
|
||||
switch inst.Op {
|
||||
case InstAlt, InstAltMatch:
|
||||
q.insert(inst.Out)
|
||||
build(inst.Out, q)
|
||||
q.insert(inst.Arg)
|
||||
case InstMatch, InstFail:
|
||||
default:
|
||||
q.insert(inst.Out)
|
||||
}
|
||||
}
|
||||
|
||||
// check that paths from Alt instructions are unambiguous, and rebuild the new
|
||||
// program as a onepass program
|
||||
check = func(pc uint32, m map[uint32]bool) (ok bool) {
|
||||
ok = true
|
||||
inst := &p.Inst[pc]
|
||||
if visitQueue.contains(pc) {
|
||||
return
|
||||
}
|
||||
visitQueue.insert(pc)
|
||||
switch inst.Op {
|
||||
case InstAlt, InstAltMatch:
|
||||
ok = check(inst.Out, m) && check(inst.Arg, m)
|
||||
// check no-input paths to InstMatch
|
||||
matchOut := m[inst.Out]
|
||||
matchArg := m[inst.Arg]
|
||||
if matchOut && matchArg {
|
||||
ok = false
|
||||
break
|
||||
}
|
||||
// Match on empty goes in inst.Out
|
||||
if matchArg {
|
||||
inst.Out, inst.Arg = inst.Arg, inst.Out
|
||||
matchOut, matchArg = matchArg, matchOut
|
||||
}
|
||||
if matchOut {
|
||||
m[pc] = true
|
||||
inst.Op = InstAltMatch
|
||||
}
|
||||
|
||||
// build a dispatch operator from the two legs of the alt.
|
||||
onePassRunes[pc], inst.Next = mergeRuneSets(
|
||||
&onePassRunes[inst.Out], &onePassRunes[inst.Arg], inst.Out, inst.Arg)
|
||||
if len(inst.Next) > 0 && inst.Next[0] == mergeFailed {
|
||||
ok = false
|
||||
break
|
||||
}
|
||||
case InstCapture, InstNop:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = m[inst.Out]
|
||||
// pass matching runes back through these no-ops.
|
||||
onePassRunes[pc] = append([]rune{}[:], onePassRunes[inst.Out][:]...)
|
||||
inst.Next = []uint32{}
|
||||
for i := len(onePassRunes[pc]) / 2; i >= 0; i-- {
|
||||
inst.Next = append(inst.Next, inst.Out)
|
||||
}
|
||||
case InstEmptyWidth:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = m[inst.Out]
|
||||
onePassRunes[pc] = append([]rune{}[:], onePassRunes[inst.Out][:]...)
|
||||
inst.Next = []uint32{}
|
||||
for i := len(onePassRunes[pc]) / 2; i >= 0; i-- {
|
||||
inst.Next = append(inst.Next, inst.Out)
|
||||
}
|
||||
case InstMatch, InstFail:
|
||||
m[pc] = inst.Op == InstMatch
|
||||
break
|
||||
case InstRune:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = false
|
||||
if len(inst.Next) > 0 {
|
||||
break
|
||||
}
|
||||
if len(inst.Rune) == 0 {
|
||||
onePassRunes[pc] = []rune{}[:]
|
||||
inst.Next = []uint32{inst.Out}
|
||||
break
|
||||
}
|
||||
runes := make([]rune, 0)
|
||||
if len(inst.Rune) == 1 && Flags(inst.Arg)&FoldCase != 0 {
|
||||
r0 := inst.Rune[0]
|
||||
runes = append(runes, r0, r0)
|
||||
for r1 := unicode.SimpleFold(r0); r1 != r0; r1 = unicode.SimpleFold(r1) {
|
||||
runes = append(runes, r1, r1)
|
||||
}
|
||||
sort.Sort(runeSlice(runes))
|
||||
} else {
|
||||
runes = append(runes, inst.Rune...)
|
||||
}
|
||||
onePassRunes[pc] = runes
|
||||
inst.Next = []uint32{}
|
||||
for i := len(onePassRunes[pc]) / 2; i >= 0; i-- {
|
||||
inst.Next = append(inst.Next, inst.Out)
|
||||
}
|
||||
inst.Op = InstRune
|
||||
case InstRune1:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = false
|
||||
if len(inst.Next) > 0 {
|
||||
break
|
||||
}
|
||||
runes := []rune{}[:]
|
||||
// expand case-folded runes
|
||||
if Flags(inst.Arg)&FoldCase != 0 {
|
||||
r0 := inst.Rune[0]
|
||||
runes = append(runes, r0, r0)
|
||||
for r1 := unicode.SimpleFold(r0); r1 != r0; r1 = unicode.SimpleFold(r1) {
|
||||
runes = append(runes, r1, r1)
|
||||
}
|
||||
sort.Sort(runeSlice(runes))
|
||||
} else {
|
||||
runes = append(runes, inst.Rune[0], inst.Rune[0])
|
||||
}
|
||||
onePassRunes[pc] = runes
|
||||
inst.Next = []uint32{}
|
||||
for i := len(onePassRunes[pc]) / 2; i >= 0; i-- {
|
||||
inst.Next = append(inst.Next, inst.Out)
|
||||
}
|
||||
inst.Op = InstRune
|
||||
case InstRuneAny:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = false
|
||||
if len(inst.Next) > 0 {
|
||||
break
|
||||
}
|
||||
onePassRunes[pc] = append([]rune{}[:], anyRune[:]...)
|
||||
inst.Next = []uint32{inst.Out}
|
||||
case InstRuneAnyNotNL:
|
||||
ok = check(inst.Out, m)
|
||||
m[pc] = false
|
||||
if len(inst.Next) > 0 {
|
||||
break
|
||||
}
|
||||
onePassRunes[pc] = append([]rune{}[:], anyRuneNotNL[:]...)
|
||||
inst.Next = []uint32{}
|
||||
for i := len(onePassRunes[pc]) / 2; i >= 0; i-- {
|
||||
inst.Next = append(inst.Next, inst.Out)
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
instQueue.clear()
|
||||
instQueue.insert(uint32(p.Start))
|
||||
m := make(map[uint32]bool, len(p.Inst))
|
||||
for !instQueue.empty() {
|
||||
pc := instQueue.next()
|
||||
inst := p.Inst[pc]
|
||||
visitQueue.clear()
|
||||
if !check(uint32(pc), m) {
|
||||
p = NotOnePass
|
||||
break
|
||||
}
|
||||
switch inst.Op {
|
||||
case InstAlt, InstAltMatch:
|
||||
instQueue.insert(inst.Out)
|
||||
instQueue.insert(inst.Arg)
|
||||
case InstCapture, InstEmptyWidth, InstNop:
|
||||
instQueue.insert(inst.Out)
|
||||
case InstMatch:
|
||||
case InstFail:
|
||||
case InstRune, InstRune1, InstRuneAny, InstRuneAnyNotNL:
|
||||
default:
|
||||
}
|
||||
}
|
||||
if p != NotOnePass {
|
||||
for i, _ := range p.Inst {
|
||||
p.Inst[i].Rune = onePassRunes[i][:]
|
||||
}
|
||||
}
|
||||
return p
|
||||
}
|
||||
|
||||
// walk visits each Inst in the prog once, and applies the argument
|
||||
// function(ip, next), in pre-order.
|
||||
func (prog *Prog) walk(funcs ...func(ip, next uint32)) {
|
||||
var walk1 func(uint32)
|
||||
progQueue := newQueue(len(prog.Inst))
|
||||
walk1 = func(ip uint32) {
|
||||
if progQueue.contains(ip) {
|
||||
return
|
||||
}
|
||||
progQueue.insert(ip)
|
||||
inst := prog.Inst[ip]
|
||||
switch inst.Op {
|
||||
case InstAlt, InstAltMatch:
|
||||
for _, f := range funcs {
|
||||
f(ip, inst.Out)
|
||||
f(ip, inst.Arg)
|
||||
}
|
||||
walk1(inst.Out)
|
||||
walk1(inst.Arg)
|
||||
default:
|
||||
for _, f := range funcs {
|
||||
f(ip, inst.Out)
|
||||
}
|
||||
walk1(inst.Out)
|
||||
}
|
||||
}
|
||||
walk1(uint32(prog.Start))
|
||||
}
|
||||
|
||||
// find returns the Insts that match the argument predicate function
|
||||
func (prog *Prog) find(f func(*Prog, int) bool) (matches []uint32) {
|
||||
matches = []uint32{}
|
||||
|
||||
for ip := range prog.Inst {
|
||||
if f(prog, ip) {
|
||||
matches = append(matches, uint32(ip))
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
var NotOnePass *Prog = nil
|
||||
var debug = false
|
||||
|
||||
// CompileOnePass returns a new *Prog suitable for onePass execution if the original Prog
|
||||
// can be recharacterized as a one-pass regexp program, or syntax.NotOnePass if the
|
||||
// Prog cannot be converted. For a one pass prog, the fundamental condition that must
|
||||
// be true is: at any InstAlt, there must be no ambiguity about what branch to take.
|
||||
func (prog *Prog) CompileOnePass() (p *Prog) {
|
||||
if prog.Start == 0 {
|
||||
return NotOnePass
|
||||
}
|
||||
// onepass regexp is anchored
|
||||
if prog.Inst[prog.Start].Op != InstEmptyWidth ||
|
||||
EmptyOp(prog.Inst[prog.Start].Arg)&EmptyBeginText != EmptyBeginText {
|
||||
return NotOnePass
|
||||
}
|
||||
// every instruction leading to InstMatch must be EmptyEndText
|
||||
for _, inst := range prog.Inst {
|
||||
opOut := prog.Inst[inst.Out].Op
|
||||
switch inst.Op {
|
||||
default:
|
||||
if opOut == InstMatch {
|
||||
return NotOnePass
|
||||
}
|
||||
case InstAlt, InstAltMatch:
|
||||
if opOut == InstMatch || prog.Inst[inst.Arg].Op == InstMatch {
|
||||
return NotOnePass
|
||||
}
|
||||
case InstEmptyWidth:
|
||||
if opOut == InstMatch {
|
||||
if EmptyOp(inst.Arg)&EmptyEndText == EmptyEndText {
|
||||
continue
|
||||
}
|
||||
return NotOnePass
|
||||
}
|
||||
}
|
||||
}
|
||||
// Creates a slightly optimized copy of the original Prog
|
||||
// that cleans up some Prog idioms that block valid onepass programs
|
||||
p = prog.onePassCopy()
|
||||
|
||||
// checkAmbiguity on InstAlts, build onepass Prog if possible
|
||||
p = p.makeOnePass()
|
||||
|
||||
if p != NotOnePass {
|
||||
p.cleanupOnePass(prog)
|
||||
}
|
||||
return p
|
||||
}
|
||||
|
||||
@ -5,6 +5,7 @@
|
||||
package syntax
|
||||
|
||||
import (
|
||||
"reflect"
|
||||
"testing"
|
||||
)
|
||||
|
||||
@ -114,3 +115,200 @@ func BenchmarkEmptyOpContext(b *testing.B) {
|
||||
EmptyOpContext(r1, -1)
|
||||
}
|
||||
}
|
||||
|
||||
var runeMergeTests = []struct {
|
||||
left, right, merged []rune
|
||||
next []uint32
|
||||
leftPC, rightPC uint32
|
||||
}{
|
||||
{
|
||||
// empty rhs
|
||||
[]rune{69, 69},
|
||||
[]rune{},
|
||||
[]rune{69, 69},
|
||||
[]uint32{1},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// identical runes, identical targets
|
||||
[]rune{69, 69},
|
||||
[]rune{69, 69},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 1,
|
||||
},
|
||||
{
|
||||
// identical runes, different targets
|
||||
[]rune{69, 69},
|
||||
[]rune{69, 69},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// append right-first
|
||||
[]rune{69, 69},
|
||||
[]rune{71, 71},
|
||||
[]rune{69, 69, 71, 71},
|
||||
[]uint32{1, 2},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// append, left-first
|
||||
[]rune{71, 71},
|
||||
[]rune{69, 69},
|
||||
[]rune{69, 69, 71, 71},
|
||||
[]uint32{2, 1},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// successful interleave
|
||||
[]rune{60, 60, 71, 71, 101, 101},
|
||||
[]rune{69, 69, 88, 88},
|
||||
[]rune{60, 60, 69, 69, 71, 71, 88, 88, 101, 101},
|
||||
[]uint32{1, 2, 1, 2, 1},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// left surrounds right
|
||||
[]rune{69, 74},
|
||||
[]rune{71, 71},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// right surrounds left
|
||||
[]rune{69, 74},
|
||||
[]rune{68, 75},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// overlap at interval begin
|
||||
[]rune{69, 74},
|
||||
[]rune{74, 75},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// overlap ar interval end
|
||||
[]rune{69, 74},
|
||||
[]rune{65, 69},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// overlap from above
|
||||
[]rune{69, 74},
|
||||
[]rune{71, 74},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// overlap from below
|
||||
[]rune{69, 74},
|
||||
[]rune{65, 71},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
{
|
||||
// out of order []rune
|
||||
[]rune{69, 74, 60, 65},
|
||||
[]rune{66, 67},
|
||||
[]rune{},
|
||||
[]uint32{mergeFailed},
|
||||
1, 2,
|
||||
},
|
||||
}
|
||||
|
||||
func TestMergeRuneSet(t *testing.T) {
|
||||
for ix, test := range runeMergeTests {
|
||||
merged, next := mergeRuneSets(&test.left, &test.right, test.leftPC, test.rightPC)
|
||||
if !reflect.DeepEqual(merged, test.merged) {
|
||||
t.Errorf("mergeRuneSet :%d (%v, %v) merged\n have\n%v\nwant\n%v", ix, test.left, test.right, merged, test.merged)
|
||||
}
|
||||
if !reflect.DeepEqual(next, test.next) {
|
||||
t.Errorf("mergeRuneSet :%d(%v, %v) next\n have\n%v\nwant\n%v", ix, test.left, test.right, next, test.next)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
const noStr = `!`
|
||||
|
||||
var onePass = &Prog{}
|
||||
|
||||
var onePassTests = []struct {
|
||||
re string
|
||||
onePass *Prog
|
||||
prog string
|
||||
}{
|
||||
{`^(?:a|(?:a*))$`, NotOnePass, noStr},
|
||||
{`^(?:(a)|(?:a*))$`, NotOnePass, noStr},
|
||||
{`^(?:(?:(?:.(?:$))?))$`, onePass, `a`},
|
||||
{`^abcd$`, onePass, `abcd`},
|
||||
{`^abcd$`, onePass, `abcde`},
|
||||
{`^(?:(?:a{0,})*?)$`, onePass, `a`},
|
||||
{`^(?:(?:a+)*)$`, onePass, ``},
|
||||
{`^(?:(?:a|(?:aa)))$`, onePass, ``},
|
||||
{`^(?:[^\s\S])$`, onePass, ``},
|
||||
{`^(?:(?:a{3,4}){0,})$`, NotOnePass, `aaaaaa`},
|
||||
{`^(?:(?:a+)*)$`, onePass, `a`},
|
||||
{`^(?:(?:(?:a*)+))$`, onePass, noStr},
|
||||
{`^(?:(?:a+)*)$`, onePass, ``},
|
||||
{`^[a-c]+$`, onePass, `abc`},
|
||||
{`^[a-c]*$`, onePass, `abcdabc`},
|
||||
{`^(?:a*)$`, onePass, `aaaaaaa`},
|
||||
{`^(?:(?:aa)|a)$`, onePass, `a`},
|
||||
{`^[a-c]*`, NotOnePass, `abcdabc`},
|
||||
{`^[a-c]*$`, onePass, `abc`},
|
||||
{`^...$`, onePass, ``},
|
||||
{`^(?:a|(?:aa))$`, onePass, `a`},
|
||||
{`^[a-c]*`, NotOnePass, `abcabc`},
|
||||
{`^a((b))c$`, onePass, noStr},
|
||||
{`^a.[l-nA-Cg-j]?e$`, onePass, noStr},
|
||||
{`^a((b))$`, onePass, noStr},
|
||||
{`^a(?:(b)|(c))c$`, onePass, noStr},
|
||||
{`^a(?:(b*)|(c))c$`, NotOnePass, noStr},
|
||||
{`^a(?:b|c)$`, onePass, noStr},
|
||||
{`^a(?:b?|c)$`, onePass, noStr},
|
||||
{`^a(?:b?|c?)$`, NotOnePass, noStr},
|
||||
{`^a(?:b?|c+)$`, onePass, noStr},
|
||||
{`^a(?:b+|(bc))d$`, NotOnePass, noStr},
|
||||
{`^a(?:bc)+$`, onePass, noStr},
|
||||
{`^a(?:[bcd])+$`, onePass, noStr},
|
||||
{`^a((?:[bcd])+)$`, onePass, noStr},
|
||||
{`^a(:?b|c)*d$`, onePass, `abbbccbbcbbd"`},
|
||||
{`^.bc(d|e)*$`, onePass, `abcddddddeeeededd`},
|
||||
{`^(?:(?:aa)|.)$`, NotOnePass, `a`},
|
||||
{`^(?:(?:a{1,2}){1,2})$`, NotOnePass, `aaaa`},
|
||||
}
|
||||
|
||||
func TestCompileOnePass(t *testing.T) {
|
||||
var (
|
||||
p *Prog
|
||||
re *Regexp
|
||||
err error
|
||||
)
|
||||
for _, test := range onePassTests {
|
||||
if re, err = Parse(test.re, Perl); err != nil {
|
||||
t.Errorf("Parse(%q) got err:%s, want success", test.re, err)
|
||||
continue
|
||||
}
|
||||
// needs to be done before compile...
|
||||
re = re.Simplify()
|
||||
if p, err = Compile(re); err != nil {
|
||||
t.Errorf("Compile(%q) got err:%s, want success", test.re, err)
|
||||
continue
|
||||
}
|
||||
onePass = p.CompileOnePass()
|
||||
if (onePass == NotOnePass) != (test.onePass == NotOnePass) {
|
||||
t.Errorf("CompileOnePass(%q) got %v, expected %v", test.re, onePass, test.onePass)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user