--- /dev/null
+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../Make.inc
+
+TARG=exp/regexp
+GOFILES=\
+ exec.go\
+ regexp.go\
+
+include ../../../Make.pkg
--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package regexp
+
+import (
+ "os"
+ "strings"
+ "testing"
+)
+
+var good_re = []string{
+ ``,
+ `.`,
+ `^.$`,
+ `a`,
+ `a*`,
+ `a+`,
+ `a?`,
+ `a|b`,
+ `a*|b*`,
+ `(a*|b)(c*|d)`,
+ `[a-z]`,
+ `[a-abc-c\-\]\[]`,
+ `[a-z]+`,
+ `[abc]`,
+ `[^1234]`,
+ `[^\n]`,
+ `\!\\`,
+}
+
+/*
+type stringError struct {
+ re string
+ err os.Error
+}
+
+var bad_re = []stringError{
+ {`*`, ErrBareClosure},
+ {`+`, ErrBareClosure},
+ {`?`, ErrBareClosure},
+ {`(abc`, ErrUnmatchedLpar},
+ {`abc)`, ErrUnmatchedRpar},
+ {`x[a-z`, ErrUnmatchedLbkt},
+ {`abc]`, ErrUnmatchedRbkt},
+ {`[z-a]`, ErrBadRange},
+ {`abc\`, ErrExtraneousBackslash},
+ {`a**`, ErrBadClosure},
+ {`a*+`, ErrBadClosure},
+ {`a??`, ErrBadClosure},
+ {`\x`, ErrBadBackslash},
+}
+*/
+
+func compileTest(t *testing.T, expr string, error os.Error) *Regexp {
+ re, err := Compile(expr)
+ if err != error {
+ t.Error("compiling `", expr, "`; unexpected error: ", err.String())
+ }
+ return re
+}
+
+func TestGoodCompile(t *testing.T) {
+ for i := 0; i < len(good_re); i++ {
+ compileTest(t, good_re[i], nil)
+ }
+}
+
+/*
+func TestBadCompile(t *testing.T) {
+ for i := 0; i < len(bad_re); i++ {
+ compileTest(t, bad_re[i].re, bad_re[i].err)
+ }
+}
+*/
+
+func matchTest(t *testing.T, test *FindTest) {
+ re := compileTest(t, test.pat, nil)
+ if re == nil {
+ return
+ }
+ m := re.MatchString(test.text)
+ if m != (len(test.matches) > 0) {
+ t.Errorf("MatchString failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+ }
+ // now try bytes
+ m = re.Match([]byte(test.text))
+ if m != (len(test.matches) > 0) {
+ t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+ }
+}
+
+func TestMatch(t *testing.T) {
+ for _, test := range findTests {
+ matchTest(t, &test)
+ }
+}
+
+func matchFunctionTest(t *testing.T, test *FindTest) {
+ m, err := MatchString(test.pat, test.text)
+ if err == nil {
+ return
+ }
+ if m != (len(test.matches) > 0) {
+ t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+ }
+}
+
+func TestMatchFunction(t *testing.T) {
+ for _, test := range findTests {
+ matchFunctionTest(t, &test)
+ }
+}
+
+type ReplaceTest struct {
+ pattern, replacement, input, output string
+}
+
+var replaceTests = []ReplaceTest{
+ // Test empty input and/or replacement, with pattern that matches the empty string.
+ {"", "", "", ""},
+ {"", "x", "", "x"},
+ {"", "", "abc", "abc"},
+ {"", "x", "abc", "xaxbxcx"},
+
+ // Test empty input and/or replacement, with pattern that does not match the empty string.
+ {"b", "", "", ""},
+ {"b", "x", "", ""},
+ {"b", "", "abc", "ac"},
+ {"b", "x", "abc", "axc"},
+ {"y", "", "", ""},
+ {"y", "x", "", ""},
+ {"y", "", "abc", "abc"},
+ {"y", "x", "abc", "abc"},
+
+ // Multibyte characters -- verify that we don't try to match in the middle
+ // of a character.
+ {"[a-c]*", "x", "\u65e5", "x\u65e5x"},
+ {"[^\u65e5]", "x", "abc\u65e5def", "xxx\u65e5xxx"},
+
+ // Start and end of a string.
+ {"^[a-c]*", "x", "abcdabc", "xdabc"},
+ {"[a-c]*$", "x", "abcdabc", "abcdx"},
+ {"^[a-c]*$", "x", "abcdabc", "abcdabc"},
+ {"^[a-c]*", "x", "abc", "x"},
+ {"[a-c]*$", "x", "abc", "x"},
+ {"^[a-c]*$", "x", "abc", "x"},
+ {"^[a-c]*", "x", "dabce", "xdabce"},
+ {"[a-c]*$", "x", "dabce", "dabcex"},
+ {"^[a-c]*$", "x", "dabce", "dabce"},
+ {"^[a-c]*", "x", "", "x"},
+ {"[a-c]*$", "x", "", "x"},
+ {"^[a-c]*$", "x", "", "x"},
+
+ {"^[a-c]+", "x", "abcdabc", "xdabc"},
+ {"[a-c]+$", "x", "abcdabc", "abcdx"},
+ {"^[a-c]+$", "x", "abcdabc", "abcdabc"},
+ {"^[a-c]+", "x", "abc", "x"},
+ {"[a-c]+$", "x", "abc", "x"},
+ {"^[a-c]+$", "x", "abc", "x"},
+ {"^[a-c]+", "x", "dabce", "dabce"},
+ {"[a-c]+$", "x", "dabce", "dabce"},
+ {"^[a-c]+$", "x", "dabce", "dabce"},
+ {"^[a-c]+", "x", "", ""},
+ {"[a-c]+$", "x", "", ""},
+ {"^[a-c]+$", "x", "", ""},
+
+ // Other cases.
+ {"abc", "def", "abcdefg", "defdefg"},
+ {"bc", "BC", "abcbcdcdedef", "aBCBCdcdedef"},
+ {"abc", "", "abcdabc", "d"},
+ {"x", "xXx", "xxxXxxx", "xXxxXxxXxXxXxxXxxXx"},
+ {"abc", "d", "", ""},
+ {"abc", "d", "abc", "d"},
+ {".+", "x", "abc", "x"},
+ {"[a-c]*", "x", "def", "xdxexfx"},
+ {"[a-c]+", "x", "abcbcdcdedef", "xdxdedef"},
+ {"[a-c]*", "x", "abcbcdcdedef", "xdxdxexdxexfx"},
+}
+
+type ReplaceFuncTest struct {
+ pattern string
+ replacement func(string) string
+ input, output string
+}
+
+var replaceFuncTests = []ReplaceFuncTest{
+ {"[a-c]", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxayxbyxcydef"},
+ {"[a-c]+", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxabcydef"},
+ {"[a-c]*", func(s string) string { return "x" + s + "y" }, "defabcdef", "xydxyexyfxabcydxyexyfxy"},
+}
+
+func TestReplaceAll(t *testing.T) {
+ for _, tc := range replaceTests {
+ re, err := Compile(tc.pattern)
+ if err != nil {
+ t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
+ continue
+ }
+ actual := re.ReplaceAllString(tc.input, tc.replacement)
+ if actual != tc.output {
+ t.Errorf("%q.Replace(%q,%q) = %q; want %q",
+ tc.pattern, tc.input, tc.replacement, actual, tc.output)
+ }
+ // now try bytes
+ actual = string(re.ReplaceAll([]byte(tc.input), []byte(tc.replacement)))
+ if actual != tc.output {
+ t.Errorf("%q.Replace(%q,%q) = %q; want %q",
+ tc.pattern, tc.input, tc.replacement, actual, tc.output)
+ }
+ }
+}
+
+func TestReplaceAllFunc(t *testing.T) {
+ for _, tc := range replaceFuncTests {
+ re, err := Compile(tc.pattern)
+ if err != nil {
+ t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
+ continue
+ }
+ actual := re.ReplaceAllStringFunc(tc.input, tc.replacement)
+ if actual != tc.output {
+ t.Errorf("%q.ReplaceFunc(%q,%q) = %q; want %q",
+ tc.pattern, tc.input, tc.replacement, actual, tc.output)
+ }
+ // now try bytes
+ actual = string(re.ReplaceAllFunc([]byte(tc.input), func(s []byte) []byte { return []byte(tc.replacement(string(s))) }))
+ if actual != tc.output {
+ t.Errorf("%q.ReplaceFunc(%q,%q) = %q; want %q",
+ tc.pattern, tc.input, tc.replacement, actual, tc.output)
+ }
+ }
+}
+
+type MetaTest struct {
+ pattern, output, literal string
+ isLiteral bool
+}
+
+var metaTests = []MetaTest{
+ {``, ``, ``, true},
+ {`foo`, `foo`, `foo`, true},
+ {`foo\.\$`, `foo\\\.\\\$`, `foo.$`, true}, // has meta but no operator
+ {`foo.\$`, `foo\.\\\$`, `foo`, false}, // has escaped operators and real operators
+ {`!@#$%^&*()_+-=[{]}\|,<.>/?~`, `!@#\$%\^&\*\(\)_\+-=\[\{\]\}\\\|,<\.>/\?~`, `!@#`, false},
+}
+
+func TestQuoteMeta(t *testing.T) {
+ for _, tc := range metaTests {
+ // Verify that QuoteMeta returns the expected string.
+ quoted := QuoteMeta(tc.pattern)
+ if quoted != tc.output {
+ t.Errorf("QuoteMeta(`%s`) = `%s`; want `%s`",
+ tc.pattern, quoted, tc.output)
+ continue
+ }
+
+ // Verify that the quoted string is in fact treated as expected
+ // by Compile -- i.e. that it matches the original, unquoted string.
+ if tc.pattern != "" {
+ re, err := Compile(quoted)
+ if err != nil {
+ t.Errorf("Unexpected error compiling QuoteMeta(`%s`): %v", tc.pattern, err)
+ continue
+ }
+ src := "abc" + tc.pattern + "def"
+ repl := "xyz"
+ replaced := re.ReplaceAllString(src, repl)
+ expected := "abcxyzdef"
+ if replaced != expected {
+ t.Errorf("QuoteMeta(`%s`).Replace(`%s`,`%s`) = `%s`; want `%s`",
+ tc.pattern, src, repl, replaced, expected)
+ }
+ }
+ }
+}
+
+func TestLiteralPrefix(t *testing.T) {
+ for _, tc := range metaTests {
+ // Literal method needs to scan the pattern.
+ re := MustCompile(tc.pattern)
+ str, complete := re.LiteralPrefix()
+ if complete != tc.isLiteral {
+ t.Errorf("LiteralPrefix(`%s`) = %t; want %t", tc.pattern, complete, tc.isLiteral)
+ }
+ if str != tc.literal {
+ t.Errorf("LiteralPrefix(`%s`) = `%s`; want `%s`", tc.pattern, str, tc.literal)
+ }
+ }
+}
+
+type numSubexpCase struct {
+ input string
+ expected int
+}
+
+var numSubexpCases = []numSubexpCase{
+ {``, 0},
+ {`.*`, 0},
+ {`abba`, 0},
+ {`ab(b)a`, 1},
+ {`ab(.*)a`, 1},
+ {`(.*)ab(.*)a`, 2},
+ {`(.*)(ab)(.*)a`, 3},
+ {`(.*)((a)b)(.*)a`, 4},
+ {`(.*)(\(ab)(.*)a`, 3},
+ {`(.*)(\(a\)b)(.*)a`, 3},
+}
+
+func TestNumSubexp(t *testing.T) {
+ for _, c := range numSubexpCases {
+ re := MustCompile(c.input)
+ n := re.NumSubexp()
+ if n != c.expected {
+ t.Errorf("NumSubexp for %q returned %d, expected %d", c.input, n, c.expected)
+ }
+ }
+}
+
+func BenchmarkLiteral(b *testing.B) {
+ x := strings.Repeat("x", 50) + "y"
+ b.StopTimer()
+ re := MustCompile("y")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ if !re.MatchString(x) {
+ println("no match!")
+ break
+ }
+ }
+}
+
+func BenchmarkNotLiteral(b *testing.B) {
+ x := strings.Repeat("x", 50) + "y"
+ b.StopTimer()
+ re := MustCompile(".y")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ if !re.MatchString(x) {
+ println("no match!")
+ break
+ }
+ }
+}
+
+func BenchmarkMatchClass(b *testing.B) {
+ b.StopTimer()
+ x := strings.Repeat("xxxx", 20) + "w"
+ re := MustCompile("[abcdw]")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ if !re.MatchString(x) {
+ println("no match!")
+ break
+ }
+ }
+}
+
+func BenchmarkMatchClass_InRange(b *testing.B) {
+ b.StopTimer()
+ // 'b' is between 'a' and 'c', so the charclass
+ // range checking is no help here.
+ x := strings.Repeat("bbbb", 20) + "c"
+ re := MustCompile("[ac]")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ if !re.MatchString(x) {
+ println("no match!")
+ break
+ }
+ }
+}
+
+func BenchmarkReplaceAll(b *testing.B) {
+ x := "abcdefghijklmnopqrstuvwxyz"
+ b.StopTimer()
+ re := MustCompile("[cjrw]")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ re.ReplaceAllString(x, "")
+ }
+}
+
+func BenchmarkAnchoredLiteralShortNonMatch(b *testing.B) {
+ b.StopTimer()
+ x := []byte("abcdefghijklmnopqrstuvwxyz")
+ re := MustCompile("^zbc(d|e)")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ re.Match(x)
+ }
+}
+
+func BenchmarkAnchoredLiteralLongNonMatch(b *testing.B) {
+ b.StopTimer()
+ x := []byte("abcdefghijklmnopqrstuvwxyz")
+ for i := 0; i < 15; i++ {
+ x = append(x, x...)
+ }
+ re := MustCompile("^zbc(d|e)")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ re.Match(x)
+ }
+}
+
+func BenchmarkAnchoredShortMatch(b *testing.B) {
+ b.StopTimer()
+ x := []byte("abcdefghijklmnopqrstuvwxyz")
+ re := MustCompile("^.bc(d|e)")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ re.Match(x)
+ }
+}
+
+func BenchmarkAnchoredLongMatch(b *testing.B) {
+ b.StopTimer()
+ x := []byte("abcdefghijklmnopqrstuvwxyz")
+ for i := 0; i < 15; i++ {
+ x = append(x, x...)
+ }
+ re := MustCompile("^.bc(d|e)")
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ re.Match(x)
+ }
+}
--- /dev/null
+package regexp
+
+import "exp/regexp/syntax"
+
+// A queue is a 'sparse array' holding pending threads of execution.
+// See http://research.swtch.com/2008/03/using-uninitialized-memory-for-fun-and.html
+type queue struct {
+ sparse []uint32
+ dense []entry
+}
+
+// A entry is an entry on a queue.
+// It holds both the instruction pc and the actual thread.
+// Some queue entries are just place holders so that the machine
+// knows it has considered that pc. Such entries have t == nil.
+type entry struct {
+ pc uint32
+ t *thread
+}
+
+// A thread is the state of a single path through the machine:
+// an instruction and a corresponding capture array.
+// See http://swtch.com/~rsc/regexp/regexp2.html
+type thread struct {
+ inst *syntax.Inst
+ cap []int
+}
+
+// A machine holds all the state during an NFA simulation for p.
+type machine struct {
+ re *Regexp // corresponding Regexp
+ p *syntax.Prog // compiled program
+ q0, q1 queue // two queues for runq, nextq
+ pool []*thread // pool of available threads
+ matched bool // whether a match was found
+ matchcap []int // capture information for the match
+}
+
+// progMachine returns a new machine running the prog p.
+func progMachine(p *syntax.Prog) *machine {
+ m := &machine{p: p}
+ 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)}
+ ncap := p.NumCap
+ if ncap < 2 {
+ ncap = 2
+ }
+ m.matchcap = make([]int, ncap)
+ return m
+}
+
+// alloc allocates a new thread with the given instruction.
+// It uses the free pool if possible.
+func (m *machine) alloc(i *syntax.Inst) *thread {
+ var t *thread
+ if n := len(m.pool); n > 0 {
+ t = m.pool[n-1]
+ m.pool = m.pool[:n-1]
+ } else {
+ t = new(thread)
+ t.cap = make([]int, cap(m.matchcap))
+ }
+ t.cap = t.cap[:len(m.matchcap)]
+ t.inst = i
+ return t
+}
+
+// free returns t to the free pool.
+func (m *machine) free(t *thread) {
+ m.pool = append(m.pool, t)
+}
+
+// match 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) match(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
+ }
+ runq, nextq := &m.q0, &m.q1
+ rune, rune1 := endOfText, endOfText
+ width, width1 := 0, 0
+ rune, width = i.step(pos)
+ if rune != endOfText {
+ rune1, width1 = i.step(pos + width)
+ }
+ // TODO: Let caller specify the initial flag setting.
+ // For now assume pos == 0 is beginning of text and
+ // pos != 0 is not even beginning of line.
+ // TODO: Word boundary.
+ var flag syntax.EmptyOp
+ if pos == 0 {
+ flag = syntax.EmptyBeginText | syntax.EmptyBeginLine
+ }
+
+ // Update flag using lookahead rune.
+ if rune1 == '\n' {
+ flag |= syntax.EmptyEndLine
+ }
+ if rune1 == endOfText {
+ flag |= syntax.EmptyEndText
+ }
+
+ for {
+ if len(runq.dense) == 0 {
+ if startCond&syntax.EmptyBeginText != 0 && pos != 0 {
+ // Anchored match, past beginning of text.
+ break
+ }
+ if m.matched {
+ // Have match; finished exploring alternatives.
+ break
+ }
+ if len(m.re.prefix) > 0 && rune1 != m.re.prefixRune && i.canCheckPrefix() {
+ // Match requires literal prefix; fast search for it.
+ advance := i.index(m.re, pos)
+ if advance < 0 {
+ break
+ }
+ pos += advance
+ rune, width = i.step(pos)
+ rune1, width1 = i.step(pos + width)
+ }
+ }
+ if !m.matched {
+ if len(m.matchcap) > 0 {
+ m.matchcap[0] = pos
+ }
+ m.add(runq, uint32(m.p.Start), pos, m.matchcap, flag)
+ }
+ // TODO: word boundary
+ flag = 0
+ if rune == '\n' {
+ flag |= syntax.EmptyBeginLine
+ }
+ if rune1 == '\n' {
+ flag |= syntax.EmptyEndLine
+ }
+ if rune1 == endOfText {
+ flag |= syntax.EmptyEndText
+ }
+ m.step(runq, nextq, pos, pos+width, rune, flag)
+ if width == 0 {
+ break
+ }
+ pos += width
+ rune, width = rune1, width1
+ if rune != endOfText {
+ rune1, width1 = i.step(pos + width)
+ }
+ runq, nextq = nextq, runq
+ }
+ m.clear(nextq)
+ return m.matched
+}
+
+// clear frees all threads on the thread queue.
+func (m *machine) clear(q *queue) {
+ for _, d := range q.dense {
+ if d.t != nil {
+ m.free(d.t)
+ }
+ }
+ q.dense = q.dense[:0]
+}
+
+// step executes one step of the machine, running each of the threads
+// on runq and appending new threads to nextq.
+// The step processes the rune c (which may be endOfText),
+// which starts at position pos and ends at nextPos.
+// nextCond gives the setting for the empty-width flags after c.
+func (m *machine) step(runq, nextq *queue, pos, nextPos, c int, nextCond syntax.EmptyOp) {
+ for j := 0; j < len(runq.dense); j++ {
+ d := &runq.dense[j]
+ t := d.t
+ if t == nil {
+ continue
+ }
+ /*
+ * If we support leftmost-longest matching:
+ if longest && matched && match[0] < t.cap[0] {
+ m.free(t)
+ continue
+ }
+ */
+
+ i := t.inst
+ switch i.Op {
+ default:
+ panic("bad inst")
+
+ case syntax.InstMatch:
+ if len(t.cap) > 0 {
+ t.cap[1] = pos
+ copy(m.matchcap, t.cap)
+ }
+ m.matched = true
+ for _, d := range runq.dense[j+1:] {
+ if d.t != nil {
+ m.free(d.t)
+ }
+ }
+ runq.dense = runq.dense[:0]
+
+ case syntax.InstRune:
+ if i.MatchRune(c) {
+ m.add(nextq, i.Out, nextPos, t.cap, nextCond)
+ }
+ }
+ m.free(t)
+ }
+ runq.dense = runq.dense[:0]
+}
+
+// add adds an entry to q for pc, unless the q already has such an entry.
+// It also recursively adds an entry for all instructions reachable from pc by following
+// empty-width conditions satisfied by cond. pos gives the current position
+// in the input.
+func (m *machine) add(q *queue, pc uint32, pos int, cap []int, cond syntax.EmptyOp) {
+ if pc == 0 {
+ return
+ }
+ if j := q.sparse[pc]; j < uint32(len(q.dense)) && q.dense[j].pc == pc {
+ return
+ }
+
+ j := len(q.dense)
+ q.dense = q.dense[:j+1]
+ d := &q.dense[j]
+ d.t = nil
+ d.pc = pc
+ q.sparse[pc] = uint32(j)
+
+ i := &m.p.Inst[pc]
+ switch i.Op {
+ default:
+ panic("unhandled")
+ case syntax.InstFail:
+ // nothing
+ case syntax.InstAlt, syntax.InstAltMatch:
+ m.add(q, i.Out, pos, cap, cond)
+ m.add(q, i.Arg, pos, cap, cond)
+ case syntax.InstEmptyWidth:
+ if syntax.EmptyOp(i.Arg)&^cond == 0 {
+ m.add(q, i.Out, pos, cap, cond)
+ }
+ case syntax.InstNop:
+ m.add(q, i.Out, pos, cap, cond)
+ case syntax.InstCapture:
+ if int(i.Arg) < len(cap) {
+ opos := cap[i.Arg]
+ cap[i.Arg] = pos
+ m.add(q, i.Out, pos, cap, cond)
+ cap[i.Arg] = opos
+ } else {
+ m.add(q, i.Out, pos, cap, cond)
+ }
+ case syntax.InstMatch, syntax.InstRune:
+ t := m.alloc(i)
+ if len(t.cap) > 0 {
+ copy(t.cap, cap)
+ }
+ d.t = t
+ }
+}
+
+// empty is a non-nil 0-element slice,
+// so doExecute can avoid an allocation
+// when 0 captures are requested from a successful match.
+var empty = make([]int, 0)
+
+// doExecute finds the leftmost match in the input and returns
+// the position of its subexpressions.
+func (re *Regexp) doExecute(i input, pos int, ncap int) []int {
+ m := re.get()
+ m.matchcap = m.matchcap[: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)
+ copy(cap, m.matchcap)
+ re.put(m)
+ return cap
+}
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package regexp
+
+import (
+ "fmt"
+ "strings"
+ "testing"
+)
+
+// For each pattern/text pair, what is the expected output of each function?
+// We can derive the textual results from the indexed results, the non-submatch
+// results from the submatched results, the single results from the 'all' results,
+// and the byte results from the string results. Therefore the table includes
+// only the FindAllStringSubmatchIndex result.
+type FindTest struct {
+ pat string
+ text string
+ matches [][]int
+}
+
+func (t FindTest) String() string {
+ return fmt.Sprintf("pat: %#q text: %#q", t.pat, t.text)
+}
+
+var findTests = []FindTest{
+ {``, ``, build(1, 0, 0)},
+ {`^abcdefg`, "abcdefg", build(1, 0, 7)},
+ {`a+`, "baaab", build(1, 1, 4)},
+ {"abcd..", "abcdef", build(1, 0, 6)},
+ {`a`, "a", build(1, 0, 1)},
+ {`x`, "y", nil},
+ {`b`, "abc", build(1, 1, 2)},
+ {`.`, "a", build(1, 0, 1)},
+ {`.*`, "abcdef", build(1, 0, 6)},
+ {`^`, "abcde", build(1, 0, 0)},
+ {`$`, "abcde", build(1, 5, 5)},
+ {`^abcd$`, "abcd", build(1, 0, 4)},
+ {`^bcd'`, "abcdef", nil},
+ {`^abcd$`, "abcde", nil},
+ {`a+`, "baaab", build(1, 1, 4)},
+ {`a*`, "baaab", build(3, 0, 0, 1, 4, 5, 5)},
+ {`[a-z]+`, "abcd", build(1, 0, 4)},
+ {`[^a-z]+`, "ab1234cd", build(1, 2, 6)},
+ {`[a\-\]z]+`, "az]-bcz", build(2, 0, 4, 6, 7)},
+ {`[^\n]+`, "abcd\n", build(1, 0, 4)},
+ {`[日本語]+`, "日本語日本語", build(1, 0, 18)},
+ {`日本語+`, "日本語", build(1, 0, 9)},
+ {`日本語+`, "日本語語語語", build(1, 0, 18)},
+ {`()`, "", build(1, 0, 0, 0, 0)},
+ {`(a)`, "a", build(1, 0, 1, 0, 1)},
+ {`(.)(.)`, "æ—¥a", build(1, 0, 4, 0, 3, 3, 4)},
+ {`(.*)`, "", build(1, 0, 0, 0, 0)},
+ {`(.*)`, "abcd", build(1, 0, 4, 0, 4)},
+ {`(..)(..)`, "abcd", build(1, 0, 4, 0, 2, 2, 4)},
+ {`(([^xyz]*)(d))`, "abcd", build(1, 0, 4, 0, 4, 0, 3, 3, 4)},
+ {`((a|b|c)*(d))`, "abcd", build(1, 0, 4, 0, 4, 2, 3, 3, 4)},
+ {`(((a|b|c)*)(d))`, "abcd", build(1, 0, 4, 0, 4, 0, 3, 2, 3, 3, 4)},
+ {`\a\f\n\r\t\v`, "\a\f\n\r\t\v", build(1, 0, 6)},
+ {`[\a\f\n\r\t\v]+`, "\a\f\n\r\t\v", build(1, 0, 6)},
+
+ {`a*(|(b))c*`, "aacc", build(1, 0, 4, 2, 2, -1, -1)},
+ {`(.*).*`, "ab", build(1, 0, 2, 0, 2)},
+ {`[.]`, ".", build(1, 0, 1)},
+ {`/$`, "/abc/", build(1, 4, 5)},
+ {`/$`, "/abc", nil},
+
+ // multiple matches
+ {`.`, "abc", build(3, 0, 1, 1, 2, 2, 3)},
+ {`(.)`, "abc", build(3, 0, 1, 0, 1, 1, 2, 1, 2, 2, 3, 2, 3)},
+ {`.(.)`, "abcd", build(2, 0, 2, 1, 2, 2, 4, 3, 4)},
+ {`ab*`, "abbaab", build(3, 0, 3, 3, 4, 4, 6)},
+ {`a(b*)`, "abbaab", build(3, 0, 3, 1, 3, 3, 4, 4, 4, 4, 6, 5, 6)},
+
+ // fixed bugs
+ {`ab$`, "cab", build(1, 1, 3)},
+ {`axxb$`, "axxcb", nil},
+ {`data`, "daXY data", build(1, 5, 9)},
+ {`da(.)a$`, "daXY data", build(1, 5, 9, 7, 8)},
+ {`zx+`, "zzx", build(1, 1, 3)},
+
+ // can backslash-escape any punctuation
+ {`\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\{\|\}\~`,
+ `!"#$%&'()*+,-./:;<=>?@[\]^_{|}~`, build(1, 0, 31)},
+ {`[\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\{\|\}\~]+`,
+ `!"#$%&'()*+,-./:;<=>?@[\]^_{|}~`, build(1, 0, 31)},
+ {"\\`", "`", build(1, 0, 1)},
+ {"[\\`]+", "`", build(1, 0, 1)},
+
+ // long set of matches (longer than startSize)
+ {
+ ".",
+ "qwertyuiopasdfghjklzxcvbnm1234567890",
+ build(36, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10,
+ 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20,
+ 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30,
+ 30, 31, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36),
+ },
+}
+
+// build is a helper to construct a [][]int by extracting n sequences from x.
+// This represents n matches with len(x)/n submatches each.
+func build(n int, x ...int) [][]int {
+ ret := make([][]int, n)
+ runLength := len(x) / n
+ j := 0
+ for i := range ret {
+ ret[i] = make([]int, runLength)
+ copy(ret[i], x[j:])
+ j += runLength
+ if j > len(x) {
+ panic("invalid build entry")
+ }
+ }
+ return ret
+}
+
+// First the simple cases.
+
+func TestFind(t *testing.T) {
+ for _, test := range findTests {
+ re := MustCompile(test.pat)
+ if re.String() != test.pat {
+ t.Errorf("String() = `%s`; should be `%s`", re.String(), test.pat)
+ }
+ result := re.Find([]byte(test.text))
+ switch {
+ case len(test.matches) == 0 && len(result) == 0:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ expect := test.text[test.matches[0][0]:test.matches[0][1]]
+ if expect != string(result) {
+ t.Errorf("expected %q got %q: %s", expect, result, test)
+ }
+ }
+ }
+}
+
+func TestFindString(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindString(test.text)
+ switch {
+ case len(test.matches) == 0 && len(result) == 0:
+ // ok
+ case test.matches == nil && result != "":
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == "":
+ // Tricky because an empty result has two meanings: no match or empty match.
+ if test.matches[0][0] != test.matches[0][1] {
+ t.Errorf("expected match; got none: %s", test)
+ }
+ case test.matches != nil && result != "":
+ expect := test.text[test.matches[0][0]:test.matches[0][1]]
+ if expect != result {
+ t.Errorf("expected %q got %q: %s", expect, result, test)
+ }
+ }
+ }
+}
+
+func testFindIndex(test *FindTest, result []int, t *testing.T) {
+ switch {
+ case len(test.matches) == 0 && len(result) == 0:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ expect := test.matches[0]
+ if expect[0] != result[0] || expect[1] != result[1] {
+ t.Errorf("expected %v got %v: %s", expect, result, test)
+ }
+ }
+}
+
+func TestFindIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindIndex(&test, MustCompile(test.pat).FindIndex([]byte(test.text)), t)
+ }
+}
+
+func TestFindStringIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindIndex(&test, MustCompile(test.pat).FindStringIndex(test.text), t)
+ }
+}
+
+func TestFindReaderIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindIndex(&test, MustCompile(test.pat).FindReaderIndex(strings.NewReader(test.text)), t)
+ }
+}
+
+// Now come the simple All cases.
+
+func TestFindAll(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindAll([]byte(test.text), -1)
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Fatalf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ if len(test.matches) != len(result) {
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ continue
+ }
+ for k, e := range test.matches {
+ expect := test.text[e[0]:e[1]]
+ if expect != string(result[k]) {
+ t.Errorf("match %d: expected %q got %q: %s", k, expect, result[k], test)
+ }
+ }
+ }
+ }
+}
+
+func TestFindAllString(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindAllString(test.text, -1)
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ if len(test.matches) != len(result) {
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ continue
+ }
+ for k, e := range test.matches {
+ expect := test.text[e[0]:e[1]]
+ if expect != result[k] {
+ t.Errorf("expected %q got %q: %s", expect, result, test)
+ }
+ }
+ }
+ }
+}
+
+func testFindAllIndex(test *FindTest, result [][]int, t *testing.T) {
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ if len(test.matches) != len(result) {
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ return
+ }
+ for k, e := range test.matches {
+ if e[0] != result[k][0] || e[1] != result[k][1] {
+ t.Errorf("match %d: expected %v got %v: %s", k, e, result[k], test)
+ }
+ }
+ }
+}
+
+func TestFindAllIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindAllIndex(&test, MustCompile(test.pat).FindAllIndex([]byte(test.text), -1), t)
+ }
+}
+
+func TestFindAllStringIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindAllIndex(&test, MustCompile(test.pat).FindAllStringIndex(test.text, -1), t)
+ }
+}
+
+// Now come the Submatch cases.
+
+func testSubmatchBytes(test *FindTest, n int, submatches []int, result [][]byte, t *testing.T) {
+ if len(submatches) != len(result)*2 {
+ t.Errorf("match %d: expected %d submatches; got %d: %s", n, len(submatches)/2, len(result), test)
+ return
+ }
+ for k := 0; k < len(submatches); k += 2 {
+ if submatches[k] == -1 {
+ if result[k/2] != nil {
+ t.Errorf("match %d: expected nil got %q: %s", n, result, test)
+ }
+ continue
+ }
+ expect := test.text[submatches[k]:submatches[k+1]]
+ if expect != string(result[k/2]) {
+ t.Errorf("match %d: expected %q got %q: %s", n, expect, result, test)
+ return
+ }
+ }
+}
+
+func TestFindSubmatch(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindSubmatch([]byte(test.text))
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ testSubmatchBytes(&test, 0, test.matches[0], result, t)
+ }
+ }
+}
+
+func testSubmatchString(test *FindTest, n int, submatches []int, result []string, t *testing.T) {
+ if len(submatches) != len(result)*2 {
+ t.Errorf("match %d: expected %d submatches; got %d: %s", n, len(submatches)/2, len(result), test)
+ return
+ }
+ for k := 0; k < len(submatches); k += 2 {
+ if submatches[k] == -1 {
+ if result[k/2] != "" {
+ t.Errorf("match %d: expected nil got %q: %s", n, result, test)
+ }
+ continue
+ }
+ expect := test.text[submatches[k]:submatches[k+1]]
+ if expect != result[k/2] {
+ t.Errorf("match %d: expected %q got %q: %s", n, expect, result, test)
+ return
+ }
+ }
+}
+
+func TestFindStringSubmatch(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindStringSubmatch(test.text)
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ testSubmatchString(&test, 0, test.matches[0], result, t)
+ }
+ }
+}
+
+func testSubmatchIndices(test *FindTest, n int, expect, result []int, t *testing.T) {
+ if len(expect) != len(result) {
+ t.Errorf("match %d: expected %d matches; got %d: %s", n, len(expect)/2, len(result)/2, test)
+ return
+ }
+ for k, e := range expect {
+ if e != result[k] {
+ t.Errorf("match %d: submatch error: expected %v got %v: %s", n, expect, result, test)
+ }
+ }
+}
+
+func testFindSubmatchIndex(test *FindTest, result []int, t *testing.T) {
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case test.matches != nil && result != nil:
+ testSubmatchIndices(test, 0, test.matches[0], result, t)
+ }
+}
+
+func TestFindSubmatchIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindSubmatchIndex(&test, MustCompile(test.pat).FindSubmatchIndex([]byte(test.text)), t)
+ }
+}
+
+func TestFindStringSubmatchIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindSubmatchIndex(&test, MustCompile(test.pat).FindStringSubmatchIndex(test.text), t)
+ }
+}
+
+func TestFindReaderSubmatchIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindSubmatchIndex(&test, MustCompile(test.pat).FindReaderSubmatchIndex(strings.NewReader(test.text)), t)
+ }
+}
+
+// Now come the monster AllSubmatch cases.
+
+func TestFindAllSubmatch(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindAllSubmatch([]byte(test.text), -1)
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case len(test.matches) != len(result):
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ case test.matches != nil && result != nil:
+ for k, match := range test.matches {
+ testSubmatchBytes(&test, k, match, result[k], t)
+ }
+ }
+ }
+}
+
+func TestFindAllStringSubmatch(t *testing.T) {
+ for _, test := range findTests {
+ result := MustCompile(test.pat).FindAllStringSubmatch(test.text, -1)
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case len(test.matches) != len(result):
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ case test.matches != nil && result != nil:
+ for k, match := range test.matches {
+ testSubmatchString(&test, k, match, result[k], t)
+ }
+ }
+ }
+}
+
+func testFindAllSubmatchIndex(test *FindTest, result [][]int, t *testing.T) {
+ switch {
+ case test.matches == nil && result == nil:
+ // ok
+ case test.matches == nil && result != nil:
+ t.Errorf("expected no match; got one: %s", test)
+ case test.matches != nil && result == nil:
+ t.Errorf("expected match; got none: %s", test)
+ case len(test.matches) != len(result):
+ t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+ case test.matches != nil && result != nil:
+ for k, match := range test.matches {
+ testSubmatchIndices(test, k, match, result[k], t)
+ }
+ }
+}
+
+func TestFindAllSubmatchIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindAllSubmatchIndex(&test, MustCompile(test.pat).FindAllSubmatchIndex([]byte(test.text), -1), t)
+ }
+}
+
+func TestFindAllStringSubmatchIndex(t *testing.T) {
+ for _, test := range findTests {
+ testFindAllSubmatchIndex(&test, MustCompile(test.pat).FindAllStringSubmatchIndex(test.text, -1), t)
+ }
+}
--- /dev/null
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package regexp implements a simple regular expression library.
+//
+// The syntax of the regular expressions accepted is the same
+// general syntax used by Perl, Python, and other languages.
+// More precisely, it is the syntax accepted by RE2 and described at
+// http://code.google.com/p/re2/wiki/Syntax, except for \C.
+//
+// All characters are UTF-8-encoded code points.
+//
+// There are 16 methods of Regexp that match a regular expression and identify
+// the matched text. Their names are matched by this regular expression:
+//
+// Find(All)?(String)?(Submatch)?(Index)?
+//
+// If 'All' is present, the routine matches successive non-overlapping
+// matches of the entire expression. Empty matches abutting a preceding
+// match are ignored. The return value is a slice containing the successive
+// return values of the corresponding non-'All' routine. These routines take
+// an extra integer argument, n; if n >= 0, the function returns at most n
+// matches/submatches.
+//
+// If 'String' is present, the argument is a string; otherwise it is a slice
+// of bytes; return values are adjusted as appropriate.
+//
+// If 'Submatch' is present, the return value is a slice identifying the
+// successive submatches of the expression. Submatches are matches of
+// parenthesized subexpressions within the regular expression, numbered from
+// left to right in order of opening parenthesis. Submatch 0 is the match of
+// the entire expression, submatch 1 the match of the first parenthesized
+// subexpression, and so on.
+//
+// If 'Index' is present, matches and submatches are identified by byte index
+// pairs within the input string: result[2*n:2*n+1] identifies the indexes of
+// the nth submatch. The pair for n==0 identifies the match of the entire
+// expression. If 'Index' is not present, the match is identified by the
+// text of the match/submatch. If an index is negative, it means that
+// subexpression did not match any string in the input.
+//
+// There is also a subset of the methods that can be applied to text read
+// from a RuneReader:
+//
+// MatchReader, FindReaderIndex, FindReaderSubmatchIndex
+//
+// This set may grow. Note that regular expression matches may need to
+// examine text beyond the text returned by a match, so the methods that
+// match text from a RuneReader may read arbitrarily far into the input
+// before returning.
+//
+// (There are a few other methods that do not match this pattern.)
+//
+package regexp
+
+import (
+ "bytes"
+ "exp/regexp/syntax"
+ "io"
+ "os"
+ "strings"
+ "sync"
+ "utf8"
+)
+
+var debug = false
+
+// Error is the local type for a parsing error.
+type Error string
+
+func (e Error) String() string {
+ return string(e)
+}
+
+// Regexp is the representation of a compiled regular expression.
+// The public interface is entirely through methods.
+// A Regexp is safe for concurrent use by multiple goroutines.
+type Regexp struct {
+ // read-only after Compile
+ expr string // as passed to Compile
+ prog *syntax.Prog // compiled program
+ prefix string // required prefix in unanchored matches
+ prefixBytes []byte // prefix, as a []byte
+ prefixComplete bool // prefix is the entire regexp
+ prefixRune int // first rune in prefix
+ cond syntax.EmptyOp // empty-width conditions required at start of match
+
+ // cache of machines for running regexp
+ mu sync.Mutex
+ machine []*machine
+}
+
+// String returns the source text used to compile the regular expression.
+func (re *Regexp) String() string {
+ return re.expr
+}
+
+// Compile parses a regular expression and returns, if successful, a Regexp
+// object that can be used to match against text.
+func Compile(expr string) (*Regexp, os.Error) {
+ re, err := syntax.Parse(expr, syntax.Perl)
+ if err != nil {
+ return nil, err
+ }
+ prog, err := syntax.Compile(re)
+ if err != nil {
+ return nil, err
+ }
+ regexp := &Regexp{
+ expr: expr,
+ prog: prog,
+ }
+ regexp.prefix, regexp.prefixComplete = prog.Prefix()
+ if regexp.prefix != "" {
+ // TODO(rsc): Remove this allocation by adding
+ // IndexString to package bytes.
+ regexp.prefixBytes = []byte(regexp.prefix)
+ regexp.prefixRune, _ = utf8.DecodeRuneInString(regexp.prefix)
+ }
+ regexp.cond = prog.StartCond()
+ return regexp, nil
+}
+
+// get returns a machine to use for matching re.
+// It uses the re's machine cache if possible, to avoid
+// unnecessary allocation.
+func (re *Regexp) get() *machine {
+ re.mu.Lock()
+ if n := len(re.machine); n > 0 {
+ z := re.machine[n-1]
+ re.machine = re.machine[:n-1]
+ re.mu.Unlock()
+ return z
+ }
+ re.mu.Unlock()
+ z := progMachine(re.prog)
+ z.re = re
+ return z
+}
+
+// put returns a machine to the re's machine cache.
+// There is no attempt to limit the size of the cache, so it will
+// grow to the maximum number of simultaneous matches
+// run using re. (The cache empties when re gets garbage collected.)
+func (re *Regexp) put(z *machine) {
+ re.mu.Lock()
+ re.machine = append(re.machine, z)
+ re.mu.Unlock()
+}
+
+// MustCompile is like Compile but panics if the expression cannot be parsed.
+// It simplifies safe initialization of global variables holding compiled regular
+// expressions.
+func MustCompile(str string) *Regexp {
+ regexp, error := Compile(str)
+ if error != nil {
+ panic(`regexp: compiling "` + str + `": ` + error.String())
+ }
+ return regexp
+}
+
+// NumSubexp returns the number of parenthesized subexpressions in this Regexp.
+func (re *Regexp) NumSubexp() int {
+ // NumCap/2 because captures count ( and ) separately.
+ // -1 because NumCap counts $0 but NumSubexp does not.
+ return re.prog.NumCap/2 - 1
+}
+
+const endOfText = -1
+
+// input abstracts different representations of the input text. It provides
+// one-character lookahead.
+type input interface {
+ step(pos int) (rune int, width int) // advance one rune
+ canCheckPrefix() bool // can we look ahead without losing info?
+ hasPrefix(re *Regexp) bool
+ index(re *Regexp, pos int) int
+}
+
+// inputString scans a string.
+type inputString struct {
+ str string
+}
+
+func newInputString(str string) *inputString {
+ return &inputString{str: str}
+}
+
+func (i *inputString) step(pos int) (int, int) {
+ if pos < len(i.str) {
+ return utf8.DecodeRuneInString(i.str[pos:len(i.str)])
+ }
+ return endOfText, 0
+}
+
+func (i *inputString) canCheckPrefix() bool {
+ return true
+}
+
+func (i *inputString) hasPrefix(re *Regexp) bool {
+ return strings.HasPrefix(i.str, re.prefix)
+}
+
+func (i *inputString) index(re *Regexp, pos int) int {
+ return strings.Index(i.str[pos:], re.prefix)
+}
+
+// inputBytes scans a byte slice.
+type inputBytes struct {
+ str []byte
+}
+
+func newInputBytes(str []byte) *inputBytes {
+ return &inputBytes{str: str}
+}
+
+func (i *inputBytes) step(pos int) (int, int) {
+ if pos < len(i.str) {
+ return utf8.DecodeRune(i.str[pos:len(i.str)])
+ }
+ return endOfText, 0
+}
+
+func (i *inputBytes) canCheckPrefix() bool {
+ return true
+}
+
+func (i *inputBytes) hasPrefix(re *Regexp) bool {
+ return bytes.HasPrefix(i.str, re.prefixBytes)
+}
+
+func (i *inputBytes) index(re *Regexp, pos int) int {
+ return bytes.Index(i.str[pos:], re.prefixBytes)
+}
+
+// inputReader scans a RuneReader.
+type inputReader struct {
+ r io.RuneReader
+ atEOT bool
+ pos int
+}
+
+func newInputReader(r io.RuneReader) *inputReader {
+ return &inputReader{r: r}
+}
+
+func (i *inputReader) step(pos int) (int, int) {
+ if !i.atEOT && pos != i.pos {
+ return endOfText, 0
+
+ }
+ r, w, err := i.r.ReadRune()
+ if err != nil {
+ i.atEOT = true
+ return endOfText, 0
+ }
+ i.pos += w
+ return r, w
+}
+
+func (i *inputReader) canCheckPrefix() bool {
+ return false
+}
+
+func (i *inputReader) hasPrefix(re *Regexp) bool {
+ return false
+}
+
+func (i *inputReader) index(re *Regexp, pos int) int {
+ return -1
+}
+
+// LiteralPrefix returns a literal string that must begin any match
+// of the regular expression re. It returns the boolean true if the
+// literal string comprises the entire regular expression.
+func (re *Regexp) LiteralPrefix() (prefix string, complete bool) {
+ return re.prefix, re.prefixComplete
+}
+
+// MatchReader returns whether the Regexp matches the text read by the
+// RuneReader. The return value is a boolean: true for match, false for no
+// match.
+func (re *Regexp) MatchReader(r io.RuneReader) bool {
+ return re.doExecute(newInputReader(r), 0, 0) != nil
+}
+
+// MatchString returns whether the Regexp matches the string s.
+// The return value is a boolean: true for match, false for no match.
+func (re *Regexp) MatchString(s string) bool {
+ return re.doExecute(newInputString(s), 0, 0) != nil
+}
+
+// Match returns whether the Regexp matches the byte slice b.
+// The return value is a boolean: true for match, false for no match.
+func (re *Regexp) Match(b []byte) bool {
+ return re.doExecute(newInputBytes(b), 0, 0) != nil
+}
+
+// MatchReader checks whether a textual regular expression matches the text
+// read by the RuneReader. More complicated queries need to use Compile and
+// the full Regexp interface.
+func MatchReader(pattern string, r io.RuneReader) (matched bool, error os.Error) {
+ re, err := Compile(pattern)
+ if err != nil {
+ return false, err
+ }
+ return re.MatchReader(r), nil
+}
+
+// MatchString checks whether a textual regular expression
+// matches a string. More complicated queries need
+// to use Compile and the full Regexp interface.
+func MatchString(pattern string, s string) (matched bool, error os.Error) {
+ re, err := Compile(pattern)
+ if err != nil {
+ return false, err
+ }
+ return re.MatchString(s), nil
+}
+
+// Match checks whether a textual regular expression
+// matches a byte slice. More complicated queries need
+// to use Compile and the full Regexp interface.
+func Match(pattern string, b []byte) (matched bool, error os.Error) {
+ re, err := Compile(pattern)
+ if err != nil {
+ return false, err
+ }
+ return re.Match(b), nil
+}
+
+// ReplaceAllString returns a copy of src in which all matches for the Regexp
+// have been replaced by repl. No support is provided for expressions
+// (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllString(src, repl string) string {
+ return re.ReplaceAllStringFunc(src, func(string) string { return repl })
+}
+
+// ReplaceAllStringFunc returns a copy of src in which all matches for the
+// Regexp have been replaced by the return value of of function repl (whose
+// first argument is the matched string). No support is provided for
+// expressions (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllStringFunc(src string, repl func(string) string) string {
+ lastMatchEnd := 0 // end position of the most recent match
+ searchPos := 0 // position where we next look for a match
+ buf := new(bytes.Buffer)
+ for searchPos <= len(src) {
+ a := re.doExecute(newInputString(src), searchPos, 2)
+ if len(a) == 0 {
+ break // no more matches
+ }
+
+ // Copy the unmatched characters before this match.
+ io.WriteString(buf, src[lastMatchEnd:a[0]])
+
+ // Now insert a copy of the replacement string, but not for a
+ // match of the empty string immediately after another match.
+ // (Otherwise, we get double replacement for patterns that
+ // match both empty and nonempty strings.)
+ if a[1] > lastMatchEnd || a[0] == 0 {
+ io.WriteString(buf, repl(src[a[0]:a[1]]))
+ }
+ lastMatchEnd = a[1]
+
+ // Advance past this match; always advance at least one character.
+ _, width := utf8.DecodeRuneInString(src[searchPos:])
+ if searchPos+width > a[1] {
+ searchPos += width
+ } else if searchPos+1 > a[1] {
+ // This clause is only needed at the end of the input
+ // string. In that case, DecodeRuneInString returns width=0.
+ searchPos++
+ } else {
+ searchPos = a[1]
+ }
+ }
+
+ // Copy the unmatched characters after the last match.
+ io.WriteString(buf, src[lastMatchEnd:])
+
+ return buf.String()
+}
+
+// ReplaceAll returns a copy of src in which all matches for the Regexp
+// have been replaced by repl. No support is provided for expressions
+// (e.g. \1 or $1) in the replacement text.
+func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
+ return re.ReplaceAllFunc(src, func([]byte) []byte { return repl })
+}
+
+// ReplaceAllFunc returns a copy of src in which all matches for the
+// Regexp have been replaced by the return value of of function repl (whose
+// first argument is the matched []byte). No support is provided for
+// expressions (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllFunc(src []byte, repl func([]byte) []byte) []byte {
+ lastMatchEnd := 0 // end position of the most recent match
+ searchPos := 0 // position where we next look for a match
+ buf := new(bytes.Buffer)
+ for searchPos <= len(src) {
+ a := re.doExecute(newInputBytes(src), searchPos, 2)
+ if len(a) == 0 {
+ break // no more matches
+ }
+
+ // Copy the unmatched characters before this match.
+ buf.Write(src[lastMatchEnd:a[0]])
+
+ // Now insert a copy of the replacement string, but not for a
+ // match of the empty string immediately after another match.
+ // (Otherwise, we get double replacement for patterns that
+ // match both empty and nonempty strings.)
+ if a[1] > lastMatchEnd || a[0] == 0 {
+ buf.Write(repl(src[a[0]:a[1]]))
+ }
+ lastMatchEnd = a[1]
+
+ // Advance past this match; always advance at least one character.
+ _, width := utf8.DecodeRune(src[searchPos:])
+ if searchPos+width > a[1] {
+ searchPos += width
+ } else if searchPos+1 > a[1] {
+ // This clause is only needed at the end of the input
+ // string. In that case, DecodeRuneInString returns width=0.
+ searchPos++
+ } else {
+ searchPos = a[1]
+ }
+ }
+
+ // Copy the unmatched characters after the last match.
+ buf.Write(src[lastMatchEnd:])
+
+ return buf.Bytes()
+}
+
+var specialBytes = []byte(`\.+*?()|[]{}^$`)
+
+func special(b byte) bool {
+ return bytes.IndexByte(specialBytes, b) >= 0
+}
+
+// QuoteMeta returns a string that quotes all regular expression metacharacters
+// inside the argument text; the returned string is a regular expression matching
+// the literal text. For example, QuoteMeta(`[foo]`) returns `\[foo\]`.
+func QuoteMeta(s string) string {
+ b := make([]byte, 2*len(s))
+
+ // A byte loop is correct because all metacharacters are ASCII.
+ j := 0
+ for i := 0; i < len(s); i++ {
+ if special(s[i]) {
+ b[j] = '\\'
+ j++
+ }
+ b[j] = s[i]
+ j++
+ }
+ return string(b[0:j])
+}
+
+// Find matches in slice b if b is non-nil, otherwise find matches in string s.
+func (re *Regexp) allMatches(s string, b []byte, n int, deliver func([]int)) {
+ var end int
+ if b == nil {
+ end = len(s)
+ } else {
+ end = len(b)
+ }
+
+ for pos, i, prevMatchEnd := 0, 0, -1; i < n && pos <= end; {
+ var in input
+ if b == nil {
+ in = newInputString(s)
+ } else {
+ in = newInputBytes(b)
+ }
+ matches := re.doExecute(in, pos, re.prog.NumCap)
+ if len(matches) == 0 {
+ break
+ }
+
+ accept := true
+ if matches[1] == pos {
+ // We've found an empty match.
+ if matches[0] == prevMatchEnd {
+ // We don't allow an empty match right
+ // after a previous match, so ignore it.
+ accept = false
+ }
+ var width int
+ // TODO: use step()
+ if b == nil {
+ _, width = utf8.DecodeRuneInString(s[pos:end])
+ } else {
+ _, width = utf8.DecodeRune(b[pos:end])
+ }
+ if width > 0 {
+ pos += width
+ } else {
+ pos = end + 1
+ }
+ } else {
+ pos = matches[1]
+ }
+ prevMatchEnd = matches[1]
+
+ if accept {
+ deliver(matches)
+ i++
+ }
+ }
+}
+
+// Find returns a slice holding the text of the leftmost match in b of the regular expression.
+// A return value of nil indicates no match.
+func (re *Regexp) Find(b []byte) []byte {
+ a := re.doExecute(newInputBytes(b), 0, 2)
+ if a == nil {
+ return nil
+ }
+ return b[a[0]:a[1]]
+}
+
+// FindIndex returns a two-element slice of integers defining the location of
+// the leftmost match in b of the regular expression. The match itself is at
+// b[loc[0]:loc[1]].
+// A return value of nil indicates no match.
+func (re *Regexp) FindIndex(b []byte) (loc []int) {
+ a := re.doExecute(newInputBytes(b), 0, 2)
+ if a == nil {
+ return nil
+ }
+ return a[0:2]
+}
+
+// FindString returns a string holding the text of the leftmost match in s of the regular
+// expression. If there is no match, the return value is an empty string,
+// but it will also be empty if the regular expression successfully matches
+// an empty string. Use FindStringIndex or FindStringSubmatch if it is
+// necessary to distinguish these cases.
+func (re *Regexp) FindString(s string) string {
+ a := re.doExecute(newInputString(s), 0, 2)
+ if a == nil {
+ return ""
+ }
+ return s[a[0]:a[1]]
+}
+
+// FindStringIndex returns a two-element slice of integers defining the
+// location of the leftmost match in s of the regular expression. The match
+// itself is at s[loc[0]:loc[1]].
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringIndex(s string) []int {
+ a := re.doExecute(newInputString(s), 0, 2)
+ if a == nil {
+ return nil
+ }
+ return a[0:2]
+}
+
+// FindReaderIndex returns a two-element slice of integers defining the
+// location of the leftmost match of the regular expression in text read from
+// the RuneReader. The match itself is at s[loc[0]:loc[1]]. A return
+// value of nil indicates no match.
+func (re *Regexp) FindReaderIndex(r io.RuneReader) []int {
+ a := re.doExecute(newInputReader(r), 0, 2)
+ if a == nil {
+ return nil
+ }
+ return a[0:2]
+}
+
+// FindSubmatch returns a slice of slices holding the text of the leftmost
+// match of the regular expression in b and the matches, if any, of its
+// subexpressions, as defined by the 'Submatch' descriptions in the package
+// comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindSubmatch(b []byte) [][]byte {
+ a := re.doExecute(newInputBytes(b), 0, re.prog.NumCap)
+ if a == nil {
+ return nil
+ }
+ ret := make([][]byte, len(a)/2)
+ for i := range ret {
+ if a[2*i] >= 0 {
+ ret[i] = b[a[2*i]:a[2*i+1]]
+ }
+ }
+ return ret
+}
+
+// FindSubmatchIndex returns a slice holding the index pairs identifying the
+// leftmost match of the regular expression in b and the matches, if any, of
+// its subexpressions, as defined by the 'Submatch' and 'Index' descriptions
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindSubmatchIndex(b []byte) []int {
+ return re.doExecute(newInputBytes(b), 0, re.prog.NumCap)
+}
+
+// FindStringSubmatch returns a slice of strings holding the text of the
+// leftmost match of the regular expression in s and the matches, if any, of
+// its subexpressions, as defined by the 'Submatch' description in the
+// package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringSubmatch(s string) []string {
+ a := re.doExecute(newInputString(s), 0, re.prog.NumCap)
+ if a == nil {
+ return nil
+ }
+ ret := make([]string, len(a)/2)
+ for i := range ret {
+ if a[2*i] >= 0 {
+ ret[i] = s[a[2*i]:a[2*i+1]]
+ }
+ }
+ return ret
+}
+
+// FindStringSubmatchIndex returns a slice holding the index pairs
+// identifying the leftmost match of the regular expression in s and the
+// matches, if any, of its subexpressions, as defined by the 'Submatch' and
+// 'Index' descriptions in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringSubmatchIndex(s string) []int {
+ return re.doExecute(newInputString(s), 0, re.prog.NumCap)
+}
+
+// FindReaderSubmatchIndex returns a slice holding the index pairs
+// identifying the leftmost match of the regular expression of text read by
+// the RuneReader, and the matches, if any, of its subexpressions, as defined
+// by the 'Submatch' and 'Index' descriptions in the package comment. A
+// return value of nil indicates no match.
+func (re *Regexp) FindReaderSubmatchIndex(r io.RuneReader) []int {
+ return re.doExecute(newInputReader(r), 0, re.prog.NumCap)
+}
+
+const startSize = 10 // The size at which to start a slice in the 'All' routines.
+
+// FindAll is the 'All' version of Find; it returns a slice of all successive
+// matches of the expression, as defined by the 'All' description in the
+// package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAll(b []byte, n int) [][]byte {
+ if n < 0 {
+ n = len(b) + 1
+ }
+ result := make([][]byte, 0, startSize)
+ re.allMatches("", b, n, func(match []int) {
+ result = append(result, b[match[0]:match[1]])
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllIndex is the 'All' version of FindIndex; it returns a slice of all
+// successive matches of the expression, as defined by the 'All' description
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllIndex(b []byte, n int) [][]int {
+ if n < 0 {
+ n = len(b) + 1
+ }
+ result := make([][]int, 0, startSize)
+ re.allMatches("", b, n, func(match []int) {
+ result = append(result, match[0:2])
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllString is the 'All' version of FindString; it returns a slice of all
+// successive matches of the expression, as defined by the 'All' description
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllString(s string, n int) []string {
+ if n < 0 {
+ n = len(s) + 1
+ }
+ result := make([]string, 0, startSize)
+ re.allMatches(s, nil, n, func(match []int) {
+ result = append(result, s[match[0]:match[1]])
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllStringIndex is the 'All' version of FindStringIndex; it returns a
+// slice of all successive matches of the expression, as defined by the 'All'
+// description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringIndex(s string, n int) [][]int {
+ if n < 0 {
+ n = len(s) + 1
+ }
+ result := make([][]int, 0, startSize)
+ re.allMatches(s, nil, n, func(match []int) {
+ result = append(result, match[0:2])
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllSubmatch is the 'All' version of FindSubmatch; it returns a slice
+// of all successive matches of the expression, as defined by the 'All'
+// description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllSubmatch(b []byte, n int) [][][]byte {
+ if n < 0 {
+ n = len(b) + 1
+ }
+ result := make([][][]byte, 0, startSize)
+ re.allMatches("", b, n, func(match []int) {
+ slice := make([][]byte, len(match)/2)
+ for j := range slice {
+ if match[2*j] >= 0 {
+ slice[j] = b[match[2*j]:match[2*j+1]]
+ }
+ }
+ result = append(result, slice)
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllSubmatchIndex is the 'All' version of FindSubmatchIndex; it returns
+// a slice of all successive matches of the expression, as defined by the
+// 'All' description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllSubmatchIndex(b []byte, n int) [][]int {
+ if n < 0 {
+ n = len(b) + 1
+ }
+ result := make([][]int, 0, startSize)
+ re.allMatches("", b, n, func(match []int) {
+ result = append(result, match)
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllStringSubmatch is the 'All' version of FindStringSubmatch; it
+// returns a slice of all successive matches of the expression, as defined by
+// the 'All' description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringSubmatch(s string, n int) [][]string {
+ if n < 0 {
+ n = len(s) + 1
+ }
+ result := make([][]string, 0, startSize)
+ re.allMatches(s, nil, n, func(match []int) {
+ slice := make([]string, len(match)/2)
+ for j := range slice {
+ if match[2*j] >= 0 {
+ slice[j] = s[match[2*j]:match[2*j+1]]
+ }
+ }
+ result = append(result, slice)
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
+
+// FindAllStringSubmatchIndex is the 'All' version of
+// FindStringSubmatchIndex; it returns a slice of all successive matches of
+// the expression, as defined by the 'All' description in the package
+// comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringSubmatchIndex(s string, n int) [][]int {
+ if n < 0 {
+ n = len(s) + 1
+ }
+ result := make([][]int, 0, startSize)
+ re.allMatches(s, nil, n, func(match []int) {
+ result = append(result, match)
+ })
+ if len(result) == 0 {
+ return nil
+ }
+ return result
+}
func (c *compiler) init() {
c.p = new(Prog)
+ c.p.NumCap = 2 // implicit ( and ) for whole match $0
c.inst(InstFail)
}
return b.String()
}
+// skipNop follows any no-op or capturing instructions
+// and returns the resulting pc.
+func (p *Prog) skipNop(pc uint32) *Inst {
+ i := &p.Inst[pc]
+ for i.Op == InstNop || i.Op == InstCapture {
+ pc = i.Out
+ i = &p.Inst[pc]
+ }
+ return i
+}
+
+// Prefix returns a literal string that all matches for the
+// 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))
+
+ // Avoid allocation of buffer if prefix is empty.
+ if i.Op != InstRune || len(i.Rune) != 1 {
+ return "", i.Op == InstMatch
+ }
+
+ // Have prefix; gather characters.
+ var buf bytes.Buffer
+ for i.Op == InstRune && len(i.Rune) == 1 {
+ buf.WriteRune(i.Rune[0])
+ i = p.skipNop(i.Out)
+ }
+ return buf.String(), i.Op == InstMatch
+}
+
+// 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 {
+ var flag EmptyOp
+ pc := uint32(p.Start)
+ i := &p.Inst[pc]
+Loop:
+ for {
+ switch i.Op {
+ case InstEmptyWidth:
+ flag |= EmptyOp(i.Arg)
+ case InstFail:
+ return ^EmptyOp(0)
+ case InstCapture, InstNop:
+ // skip
+ default:
+ break Loop
+ }
+ pc = i.Out
+ i = &p.Inst[pc]
+ }
+ return flag
+}
+
// MatchRune returns true if the instruction matches (and consumes) r.
// It should only be called when i.Op == InstRune.
func (i *Inst) MatchRune(r int) bool {