regexp: eliminate vector in favor of append.

R=rsc
CC=golang-dev
https://golang.org/cl/2795041

diff --git a/src/pkg/regexp/regexp.go b/src/pkg/regexp/regexp.go
index 00ff76fe3a17d0a196f92f99c30e6897375a1f8f..d3f03ad790b1f890d5f0fb9bb8ccc83acec526f0 100644 (file)
--- a/src/pkg/regexp/regexp.go
+++ b/src/pkg/regexp/regexp.go
@@ -60,7 +60,6 @@ package regexp
 
 import (
        "bytes"
-       "container/vector"
        "io"
        "os"
        "strings"
@@ -117,7 +116,7 @@ type Regexp struct {
        expr        string // the original expression
        prefix      string // initial plain text string
        prefixBytes []byte // initial plain text bytes
-       inst        *vector.Vector
+       inst        []instr
        start       instr // first instruction of machine
        prefixStart instr // where to start if there is a prefix
        nbra        int   // number of brackets in expression, for subexpressions
@@ -190,8 +189,8 @@ func newChar(char int) *_Char {
 type _CharClass struct {
        common
        negate bool // is character class negated? ([^a-z])
-       // vector of int, stored pairwise: [a-z] is (a,z); x is (x,x):
-       ranges     *vector.IntVector
+       // slice of int, stored pairwise: [a-z] is (a,z); x is (x,x):
+       ranges     []int
        cmin, cmax int
 }
 
@@ -202,9 +201,9 @@ func (cclass *_CharClass) print() {
        if cclass.negate {
                print(" (negated)")
        }
-       for i := 0; i < cclass.ranges.Len(); i += 2 {
-               l := cclass.ranges.At(i)
-               r := cclass.ranges.At(i + 1)
+       for i := 0; i < len(cclass.ranges); i += 2 {
+               l := cclass.ranges[i]
+               r := cclass.ranges[i+1]
                if l == r {
                        print(" [", string(l), "]")
                } else {
@@ -215,8 +214,7 @@ func (cclass *_CharClass) print() {
 
 func (cclass *_CharClass) addRange(a, b int) {
        // range is a through b inclusive
-       cclass.ranges.Push(a)
-       cclass.ranges.Push(b)
+       cclass.ranges = append(cclass.ranges, a, b)
        if a < cclass.cmin {
                cclass.cmin = a
        }
@@ -229,7 +227,7 @@ func (cclass *_CharClass) matches(c int) bool {
        if c < cclass.cmin || c > cclass.cmax {
                return cclass.negate
        }
-       ranges := []int(*cclass.ranges)
+       ranges := cclass.ranges
        for i := 0; i < len(ranges); i = i + 2 {
                if ranges[i] <= c && c <= ranges[i+1] {
                        return !cclass.negate
@@ -240,7 +238,7 @@ func (cclass *_CharClass) matches(c int) bool {
 
 func newCharClass() *_CharClass {
        c := new(_CharClass)
-       c.ranges = new(vector.IntVector)
+       c.ranges = make([]int, 0, 4)
        c.cmin = 0x10FFFF + 1 // MaxRune + 1
        c.cmax = -1
        return c
@@ -298,8 +296,8 @@ func (nop *_Nop) kind() int { return _NOP }
 func (nop *_Nop) print()    { print("nop") }
 
 func (re *Regexp) add(i instr) instr {
-       i.setIndex(re.inst.Len())
-       re.inst.Push(i)
+       i.setIndex(len(re.inst))
+       re.inst = append(re.inst, i)
        return i
 }
 
@@ -380,15 +378,15 @@ func (p *parser) charClass() instr {
                                p.error(ErrBadRange)
                        }
                        // Is it [^\n]?
-                       if cc.negate && cc.ranges.Len() == 2 &&
-                               cc.ranges.At(0) == '\n' && cc.ranges.At(1) == '\n' {
+                       if cc.negate && len(cc.ranges) == 2 &&
+                               cc.ranges[0] == '\n' && cc.ranges[1] == '\n' {
                                nl := new(_NotNl)
                                p.re.add(nl)
                                return nl
                        }
                        // Special common case: "[a]" -> "a"
-                       if !cc.negate && cc.ranges.Len() == 2 && cc.ranges.At(0) == cc.ranges.At(1) {
-                               c := newChar(cc.ranges.At(0))
+                       if !cc.negate && len(cc.ranges) == 2 && cc.ranges[0] == cc.ranges[1] {
+                               c := newChar(cc.ranges[0])
                                p.re.add(c)
                                return c
                        }
@@ -606,8 +604,7 @@ func unNop(i instr) instr {
 }
 
 func (re *Regexp) eliminateNops() {
-       for i := 0; i < re.inst.Len(); i++ {
-               inst := re.inst.At(i).(instr)
+       for _, inst := range re.inst {
                if inst.kind() == _END {
                        continue
                }
@@ -621,8 +618,7 @@ func (re *Regexp) eliminateNops() {
 
 func (re *Regexp) dump() {
        print("prefix <", re.prefix, ">\n")
-       for i := 0; i < re.inst.Len(); i++ {
-               inst := re.inst.At(i).(instr)
+       for _, inst := range re.inst {
                print(inst.index(), ": ")
                inst.print()
                if inst.kind() != _END {
@@ -664,17 +660,17 @@ func (re *Regexp) setPrefix() {
        var b []byte
        var utf = make([]byte, utf8.UTFMax)
        // First instruction is start; skip that.
-       i := re.inst.At(0).(instr).next().index()
+       i := re.inst[0].next().index()
 Loop:
-       for i < re.inst.Len() {
-               inst := re.inst.At(i).(instr)
+       for i < len(re.inst) {
+               inst := re.inst[i]
                // stop if this is not a char
                if inst.kind() != _CHAR {
                        break
                }
                // stop if this char can be followed by a match for an empty string,
                // which includes closures, ^, and $.
-               switch re.inst.At(inst.next().index()).(instr).kind() {
+               switch re.inst[inst.next().index()].kind() {
                case _BOT, _EOT, _ALT:
                        break Loop
                }
@@ -683,7 +679,7 @@ Loop:
                i = inst.next().index()
        }
        // point prefixStart instruction to first non-CHAR after prefix
-       re.prefixStart = re.inst.At(i).(instr)
+       re.prefixStart = re.inst[i]
        re.prefixBytes = b
        re.prefix = string(b)
 }
@@ -700,7 +696,7 @@ func Compile(str string) (regexp *Regexp, error os.Error) {
                }
        }()
        regexp.expr = str
-       regexp.inst = new(vector.Vector)
+       regexp.inst = make([]instr, 0, 10)
        regexp.doParse()
        return
 }
@@ -830,8 +826,8 @@ func (a *matchArena) addState(s []state, inst instr, prefixed bool, match *match
 // If bytes == nil, scan str.
 func (re *Regexp) doExecute(str string, bytestr []byte, pos int) []int {
        var s [2][]state
-       s[0] = make([]state, 10)[0:0]
-       s[1] = make([]state, 10)[0:0]
+       s[0] = make([]state, 0, 10)
+       s[1] = make([]state, 0, 10)
        in, out := 0, 1
        var final state
        found := false