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https://github.com/golang/go
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regexp: eliminate vector in favor of append.
R=rsc CC=golang-dev https://golang.org/cl/2795041
This commit is contained in:
Rob Pike
parent
fafb116c75
commit
1f4d54ea01
@ -60,7 +60,6 @@ package regexp
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import (
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"bytes"
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"container/vector"
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"io"
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"os"
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"strings"
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@ -117,7 +116,7 @@ type Regexp struct {
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expr string // the original expression
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prefix string // initial plain text string
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prefixBytes []byte // initial plain text bytes
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inst *vector.Vector
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inst []instr
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start instr // first instruction of machine
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prefixStart instr // where to start if there is a prefix
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nbra int // number of brackets in expression, for subexpressions
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@ -190,8 +189,8 @@ func newChar(char int) *_Char {
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type _CharClass struct {
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common
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negate bool // is character class negated? ([^a-z])
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// vector of int, stored pairwise: [a-z] is (a,z); x is (x,x):
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ranges *vector.IntVector
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// slice of int, stored pairwise: [a-z] is (a,z); x is (x,x):
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ranges []int
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cmin, cmax int
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}
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@ -202,9 +201,9 @@ func (cclass *_CharClass) print() {
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if cclass.negate {
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print(" (negated)")
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}
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for i := 0; i < cclass.ranges.Len(); i += 2 {
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l := cclass.ranges.At(i)
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r := cclass.ranges.At(i + 1)
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for i := 0; i < len(cclass.ranges); i += 2 {
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l := cclass.ranges[i]
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r := cclass.ranges[i+1]
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if l == r {
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print(" [", string(l), "]")
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} else {
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@ -215,8 +214,7 @@ func (cclass *_CharClass) print() {
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func (cclass *_CharClass) addRange(a, b int) {
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// range is a through b inclusive
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cclass.ranges.Push(a)
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cclass.ranges.Push(b)
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cclass.ranges = append(cclass.ranges, a, b)
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if a < cclass.cmin {
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cclass.cmin = a
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}
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@ -229,7 +227,7 @@ func (cclass *_CharClass) matches(c int) bool {
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if c < cclass.cmin || c > cclass.cmax {
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return cclass.negate
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}
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ranges := []int(*cclass.ranges)
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ranges := cclass.ranges
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for i := 0; i < len(ranges); i = i + 2 {
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if ranges[i] <= c && c <= ranges[i+1] {
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return !cclass.negate
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@ -240,7 +238,7 @@ func (cclass *_CharClass) matches(c int) bool {
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func newCharClass() *_CharClass {
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c := new(_CharClass)
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c.ranges = new(vector.IntVector)
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c.ranges = make([]int, 0, 4)
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c.cmin = 0x10FFFF + 1 // MaxRune + 1
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c.cmax = -1
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return c
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@ -298,8 +296,8 @@ func (nop *_Nop) kind() int { return _NOP }
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func (nop *_Nop) print() { print("nop") }
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func (re *Regexp) add(i instr) instr {
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i.setIndex(re.inst.Len())
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re.inst.Push(i)
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i.setIndex(len(re.inst))
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re.inst = append(re.inst, i)
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return i
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}
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@ -380,15 +378,15 @@ func (p *parser) charClass() instr {
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p.error(ErrBadRange)
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}
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// Is it [^\n]?
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if cc.negate && cc.ranges.Len() == 2 &&
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cc.ranges.At(0) == '\n' && cc.ranges.At(1) == '\n' {
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if cc.negate && len(cc.ranges) == 2 &&
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cc.ranges[0] == '\n' && cc.ranges[1] == '\n' {
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nl := new(_NotNl)
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p.re.add(nl)
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return nl
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}
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// Special common case: "[a]" -> "a"
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if !cc.negate && cc.ranges.Len() == 2 && cc.ranges.At(0) == cc.ranges.At(1) {
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c := newChar(cc.ranges.At(0))
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if !cc.negate && len(cc.ranges) == 2 && cc.ranges[0] == cc.ranges[1] {
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c := newChar(cc.ranges[0])
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p.re.add(c)
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return c
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}
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@ -606,8 +604,7 @@ func unNop(i instr) instr {
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}
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func (re *Regexp) eliminateNops() {
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for i := 0; i < re.inst.Len(); i++ {
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inst := re.inst.At(i).(instr)
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for _, inst := range re.inst {
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if inst.kind() == _END {
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continue
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}
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@ -621,8 +618,7 @@ func (re *Regexp) eliminateNops() {
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func (re *Regexp) dump() {
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print("prefix <", re.prefix, ">\n")
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for i := 0; i < re.inst.Len(); i++ {
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inst := re.inst.At(i).(instr)
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for _, inst := range re.inst {
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print(inst.index(), ": ")
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inst.print()
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if inst.kind() != _END {
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@ -664,17 +660,17 @@ func (re *Regexp) setPrefix() {
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var b []byte
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var utf = make([]byte, utf8.UTFMax)
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// First instruction is start; skip that.
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i := re.inst.At(0).(instr).next().index()
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i := re.inst[0].next().index()
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Loop:
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for i < re.inst.Len() {
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inst := re.inst.At(i).(instr)
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for i < len(re.inst) {
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inst := re.inst[i]
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// stop if this is not a char
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if inst.kind() != _CHAR {
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break
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}
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// stop if this char can be followed by a match for an empty string,
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// which includes closures, ^, and $.
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switch re.inst.At(inst.next().index()).(instr).kind() {
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switch re.inst[inst.next().index()].kind() {
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case _BOT, _EOT, _ALT:
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break Loop
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}
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@ -683,7 +679,7 @@ Loop:
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i = inst.next().index()
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}
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// point prefixStart instruction to first non-CHAR after prefix
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re.prefixStart = re.inst.At(i).(instr)
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re.prefixStart = re.inst[i]
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re.prefixBytes = b
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re.prefix = string(b)
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}
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@ -700,7 +696,7 @@ func Compile(str string) (regexp *Regexp, error os.Error) {
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}
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}()
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regexp.expr = str
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regexp.inst = new(vector.Vector)
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regexp.inst = make([]instr, 0, 10)
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regexp.doParse()
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return
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}
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@ -830,8 +826,8 @@ func (a *matchArena) addState(s []state, inst instr, prefixed bool, match *match
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// If bytes == nil, scan str.
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func (re *Regexp) doExecute(str string, bytestr []byte, pos int) []int {
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var s [2][]state
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s[0] = make([]state, 10)[0:0]
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s[1] = make([]state, 10)[0:0]
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s[0] = make([]state, 0, 10)
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s[1] = make([]state, 0, 10)
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in, out := 0, 1
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var final state
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found := false
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