mirror of
https://github.com/golang/go.git
synced 2025-12-08 06:10:04 +00:00
mv src/lib to src/pkg
tests: all.bash passes, gobuild still works, godoc still works. R=rsc OCL=30096 CL=30102
This commit is contained in:
Rob Pike
parent
bf5c0c957c
commit
d90e7cbac6
391 changed files with 14 additions and 48 deletions
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@ -1,764 +0,0 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package regexp implements a simple regular expression library.
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//
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// The syntax of the regular expressions accepted is:
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//
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// regexp:
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// concatenation { '|' concatenation }
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// concatenation:
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// { closure }
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// closure:
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// term [ '*' | '+' | '?' ]
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// term:
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// '^'
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// '$'
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// '.'
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// character
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// '[' [ '^' ] character-ranges ']'
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// '(' regexp ')'
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//
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package regexp
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import (
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"container/vector";
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"os";
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"runtime";
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"utf8";
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)
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var debug = false;
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// Error codes returned by failures to parse an expression.
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var (
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ErrInternal = os.NewError("internal error");
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ErrUnmatchedLpar = os.NewError("unmatched '('");
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ErrUnmatchedRpar = os.NewError("unmatched ')'");
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ErrUnmatchedLbkt = os.NewError("unmatched '['");
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ErrUnmatchedRbkt = os.NewError("unmatched ']'");
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ErrBadRange = os.NewError("bad range in character class");
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ErrExtraneousBackslash = os.NewError("extraneous backslash");
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ErrBadClosure = os.NewError("repeated closure (**, ++, etc.)");
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ErrBareClosure = os.NewError("closure applies to nothing");
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ErrBadBackslash = os.NewError("illegal backslash escape");
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)
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// An instruction executed by the NFA
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type instr interface {
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kind() int; // the type of this instruction: _CHAR, _ANY, etc.
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next() instr; // the instruction to execute after this one
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setNext(i instr);
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index() int;
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setIndex(i int);
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print();
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}
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// Fields and methods common to all instructions
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type common struct {
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_next instr;
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_index int;
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}
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func (c *common) next() instr { return c._next }
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func (c *common) setNext(i instr) { c._next = i }
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func (c *common) index() int { return c._index }
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func (c *common) setIndex(i int) { c._index = i }
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// The representation of a compiled regular expression.
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// The public interface is entirely through methods.
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type Regexp struct {
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expr string; // the original expression
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ch chan<- *Regexp; // reply channel when we're done
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error os.Error; // compile- or run-time error; nil if OK
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inst *vector.Vector;
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start instr;
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nbra int; // number of brackets in expression, for subexpressions
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}
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const (
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_START // beginning of program
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= iota;
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_END; // end of program: success
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_BOT; // '^' beginning of text
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_EOT; // '$' end of text
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_CHAR; // 'a' regular character
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_CHARCLASS; // [a-z] character class
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_ANY; // '.' any character
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_BRA; // '(' parenthesized expression
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_EBRA; // ')'; end of '(' parenthesized expression
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_ALT; // '|' alternation
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_NOP; // do nothing; makes it easy to link without patching
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)
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// --- START start of program
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type _Start struct {
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common
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}
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func (start *_Start) kind() int { return _START }
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func (start *_Start) print() { print("start") }
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// --- END end of program
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type _End struct {
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common
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}
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func (end *_End) kind() int { return _END }
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func (end *_End) print() { print("end") }
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// --- BOT beginning of text
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type _Bot struct {
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common
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}
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func (bot *_Bot) kind() int { return _BOT }
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func (bot *_Bot) print() { print("bot") }
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// --- EOT end of text
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type _Eot struct {
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common
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}
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func (eot *_Eot) kind() int { return _EOT }
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func (eot *_Eot) print() { print("eot") }
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// --- CHAR a regular character
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type _Char struct {
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common;
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char int;
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}
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func (char *_Char) kind() int { return _CHAR }
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func (char *_Char) print() { print("char ", string(char.char)) }
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func newChar(char int) *_Char {
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c := new(_Char);
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c.char = char;
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return c;
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}
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// --- CHARCLASS [a-z]
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type _CharClass struct {
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common;
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char int;
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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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}
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func (cclass *_CharClass) kind() int { return _CHARCLASS }
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func (cclass *_CharClass) print() {
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print("charclass");
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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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if l == r {
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print(" [", string(l), "]");
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} else {
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print(" [", string(l), "-", string(r), "]");
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}
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}
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}
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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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}
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func (cclass *_CharClass) matches(c int) bool {
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for i := 0; i < cclass.ranges.Len(); i = i+2 {
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min := cclass.ranges.At(i);
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max := cclass.ranges.At(i+1);
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if min <= c && c <= max {
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return !cclass.negate
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}
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}
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return cclass.negate
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}
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func newCharClass() *_CharClass {
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c := new(_CharClass);
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c.ranges = vector.NewIntVector(0);
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return c;
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}
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// --- ANY any character
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type _Any struct {
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common
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}
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func (any *_Any) kind() int { return _ANY }
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func (any *_Any) print() { print("any") }
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// --- BRA parenthesized expression
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type _Bra struct {
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common;
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n int; // subexpression number
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}
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func (bra *_Bra) kind() int { return _BRA }
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func (bra *_Bra) print() { print("bra", bra.n); }
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// --- EBRA end of parenthesized expression
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type _Ebra struct {
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common;
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n int; // subexpression number
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}
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func (ebra *_Ebra) kind() int { return _EBRA }
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func (ebra *_Ebra) print() { print("ebra ", ebra.n); }
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// --- ALT alternation
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type _Alt struct {
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common;
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left instr; // other branch
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}
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func (alt *_Alt) kind() int { return _ALT }
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func (alt *_Alt) print() { print("alt(", alt.left.index(), ")"); }
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// --- NOP no operation
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type _Nop struct {
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common
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}
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func (nop *_Nop) kind() int { return _NOP }
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func (nop *_Nop) print() { print("nop") }
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// report error and exit compiling/executing goroutine
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func (re *Regexp) setError(err os.Error) {
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re.error = err;
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re.ch <- re;
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runtime.Goexit();
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}
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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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return i;
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}
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type parser struct {
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re *Regexp;
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nlpar int; // number of unclosed lpars
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pos int;
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ch int;
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}
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const endOfFile = -1
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func (p *parser) c() int {
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return p.ch;
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}
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func (p *parser) nextc() int {
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if p.pos >= len(p.re.expr) {
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p.ch = endOfFile
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} else {
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c, w := utf8.DecodeRuneInString(p.re.expr[p.pos:len(p.re.expr)]);
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p.ch = c;
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p.pos += w;
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}
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return p.ch;
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}
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func newParser(re *Regexp) *parser {
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p := new(parser);
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p.re = re;
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p.nextc(); // load p.ch
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return p;
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}
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func (p *parser) regexp() (start, end instr)
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var iNULL instr
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func special(c int) bool {
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s := `\.+*?()|[]`;
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for i := 0; i < len(s); i++ {
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if c == int(s[i]) {
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return true
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}
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}
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return false
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}
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func specialcclass(c int) bool {
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s := `\-[]`;
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for i := 0; i < len(s); i++ {
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if c == int(s[i]) {
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return true
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}
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}
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return false
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}
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func (p *parser) charClass() instr {
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cc := newCharClass();
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p.re.add(cc);
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if p.c() == '^' {
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cc.negate = true;
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p.nextc();
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}
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left := -1;
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for {
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switch c := p.c(); c {
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case ']', endOfFile:
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if left >= 0 {
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p.re.setError(ErrBadRange);
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}
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return cc;
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case '-': // do this before backslash processing
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p.re.setError(ErrBadRange);
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case '\\':
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c = p.nextc();
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switch {
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case c == endOfFile:
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p.re.setError(ErrExtraneousBackslash);
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case c == 'n':
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c = '\n';
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case specialcclass(c):
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// c is as delivered
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default:
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p.re.setError(ErrBadBackslash);
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}
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fallthrough;
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default:
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p.nextc();
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switch {
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case left < 0: // first of pair
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if p.c() == '-' { // range
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p.nextc();
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left = c;
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} else { // single char
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cc.addRange(c, c);
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}
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case left <= c: // second of pair
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cc.addRange(left, c);
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left = -1;
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default:
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p.re.setError(ErrBadRange);
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}
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}
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}
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return iNULL
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}
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func (p *parser) term() (start, end instr) {
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switch c := p.c(); c {
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case '|', endOfFile:
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return iNULL, iNULL;
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case '*', '+':
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p.re.setError(ErrBareClosure);
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case ')':
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if p.nlpar == 0 {
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p.re.setError(ErrUnmatchedRpar);
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}
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return iNULL, iNULL;
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case ']':
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p.re.setError(ErrUnmatchedRbkt);
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case '^':
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p.nextc();
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start = p.re.add(new(_Bot));
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return start, start;
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case '$':
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p.nextc();
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start = p.re.add(new(_Eot));
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return start, start;
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case '.':
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p.nextc();
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start = p.re.add(new(_Any));
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return start, start;
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case '[':
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p.nextc();
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start = p.charClass();
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if p.c() != ']' {
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p.re.setError(ErrUnmatchedLbkt);
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}
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p.nextc();
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return start, start;
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case '(':
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p.nextc();
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p.nlpar++;
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p.re.nbra++; // increment first so first subexpr is \1
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nbra := p.re.nbra;
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start, end = p.regexp();
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if p.c() != ')' {
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p.re.setError(ErrUnmatchedLpar);
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}
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p.nlpar--;
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p.nextc();
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bra := new(_Bra);
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p.re.add(bra);
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ebra := new(_Ebra);
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p.re.add(ebra);
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bra.n = nbra;
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ebra.n = nbra;
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if start == iNULL {
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if end == iNULL {
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p.re.setError(ErrInternal)
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}
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start = ebra
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} else {
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end.setNext(ebra);
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}
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bra.setNext(start);
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return bra, ebra;
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case '\\':
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c = p.nextc();
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switch {
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case c == endOfFile:
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p.re.setError(ErrExtraneousBackslash);
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case c == 'n':
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c = '\n';
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case special(c):
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// c is as delivered
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default:
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p.re.setError(ErrBadBackslash);
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}
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fallthrough;
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default:
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p.nextc();
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start = newChar(c);
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p.re.add(start);
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return start, start
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}
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panic("unreachable");
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}
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func (p *parser) closure() (start, end instr) {
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start, end = p.term();
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if start == iNULL {
|
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return
|
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}
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switch p.c() {
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case '*':
|
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// (start,end)*:
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alt := new(_Alt);
|
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p.re.add(alt);
|
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end.setNext(alt); // after end, do alt
|
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alt.left = start; // alternate brach: return to start
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start = alt; // alt becomes new (start, end)
|
||||
end = alt;
|
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case '+':
|
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// (start,end)+:
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alt := new(_Alt);
|
||||
p.re.add(alt);
|
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end.setNext(alt); // after end, do alt
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alt.left = start; // alternate brach: return to start
|
||||
end = alt; // start is unchanged; end is alt
|
||||
case '?':
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// (start,end)?:
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alt := new(_Alt);
|
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p.re.add(alt);
|
||||
nop := new(_Nop);
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||||
p.re.add(nop);
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alt.left = start; // alternate branch is start
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||||
alt.setNext(nop); // follow on to nop
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||||
end.setNext(nop); // after end, go to nop
|
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start = alt; // start is now alt
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||||
end = nop; // end is nop pointed to by both branches
|
||||
default:
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return
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}
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||||
switch p.nextc() {
|
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case '*', '+', '?':
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||||
p.re.setError(ErrBadClosure);
|
||||
}
|
||||
return
|
||||
}
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||||
|
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func (p *parser) concatenation() (start, end instr) {
|
||||
start, end = iNULL, iNULL;
|
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for {
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nstart, nend := p.closure();
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||||
switch {
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||||
case nstart == iNULL: // end of this concatenation
|
||||
if start == iNULL { // this is the empty string
|
||||
nop := p.re.add(new(_Nop));
|
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return nop, nop;
|
||||
}
|
||||
return;
|
||||
case start == iNULL: // this is first element of concatenation
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||||
start, end = nstart, nend;
|
||||
default:
|
||||
end.setNext(nstart);
|
||||
end = nend;
|
||||
}
|
||||
}
|
||||
panic("unreachable");
|
||||
}
|
||||
|
||||
func (p *parser) regexp() (start, end instr) {
|
||||
start, end = p.concatenation();
|
||||
for {
|
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switch p.c() {
|
||||
default:
|
||||
return;
|
||||
case '|':
|
||||
p.nextc();
|
||||
nstart, nend := p.concatenation();
|
||||
alt := new(_Alt);
|
||||
p.re.add(alt);
|
||||
alt.left = start;
|
||||
alt.setNext(nstart);
|
||||
nop := new(_Nop);
|
||||
p.re.add(nop);
|
||||
end.setNext(nop);
|
||||
nend.setNext(nop);
|
||||
start, end = alt, nop;
|
||||
}
|
||||
}
|
||||
panic("unreachable");
|
||||
}
|
||||
|
||||
func unNop(i instr) instr {
|
||||
for i.kind() == _NOP {
|
||||
i = i.next()
|
||||
}
|
||||
return i
|
||||
}
|
||||
|
||||
func (re *Regexp) eliminateNops() {
|
||||
for i := 0; i < re.inst.Len(); i++ {
|
||||
inst := re.inst.At(i).(instr);
|
||||
if inst.kind() == _END {
|
||||
continue
|
||||
}
|
||||
inst.setNext(unNop(inst.next()));
|
||||
if inst.kind() == _ALT {
|
||||
alt := inst.(*_Alt);
|
||||
alt.left = unNop(alt.left);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (re *Regexp) dump() {
|
||||
for i := 0; i < re.inst.Len(); i++ {
|
||||
inst := re.inst.At(i).(instr);
|
||||
print(inst.index(), ": ");
|
||||
inst.print();
|
||||
if inst.kind() != _END {
|
||||
print(" -> ", inst.next().index())
|
||||
}
|
||||
print("\n");
|
||||
}
|
||||
}
|
||||
|
||||
func (re *Regexp) doParse() {
|
||||
p := newParser(re);
|
||||
start := new(_Start);
|
||||
re.add(start);
|
||||
s, e := p.regexp();
|
||||
start.setNext(s);
|
||||
re.start = start;
|
||||
e.setNext(re.add(new(_End)));
|
||||
|
||||
if debug {
|
||||
re.dump();
|
||||
println();
|
||||
}
|
||||
|
||||
re.eliminateNops();
|
||||
|
||||
if debug {
|
||||
re.dump();
|
||||
println();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
func compiler(str string, ch chan *Regexp) {
|
||||
re := new(Regexp);
|
||||
re.expr = str;
|
||||
re.inst = vector.New(0);
|
||||
re.ch = ch;
|
||||
re.doParse();
|
||||
ch <- re;
|
||||
}
|
||||
|
||||
// Compile parses a regular expression and returns, if successful, a Regexp
|
||||
// object that can be used to match against text.
|
||||
func Compile(str string) (regexp *Regexp, error os.Error) {
|
||||
// Compile in a separate goroutine and wait for the result.
|
||||
ch := make(chan *Regexp);
|
||||
go compiler(str, ch);
|
||||
re := <-ch;
|
||||
return re, re.error
|
||||
}
|
||||
|
||||
type state struct {
|
||||
inst instr; // next instruction to execute
|
||||
match []int; // pairs of bracketing submatches. 0th is start,end
|
||||
}
|
||||
|
||||
// Append new state to to-do list. Leftmost-longest wins so avoid
|
||||
// adding a state that's already active.
|
||||
func addState(s []state, inst instr, match []int) []state {
|
||||
index := inst.index();
|
||||
l := len(s);
|
||||
pos := match[0];
|
||||
// TODO: Once the state is a vector and we can do insert, have inputs always
|
||||
// go in order correctly and this "earlier" test is never necessary,
|
||||
for i := 0; i < l; i++ {
|
||||
if s[i].inst.index() == index && // same instruction
|
||||
s[i].match[0] < pos { // earlier match already going; lefmost wins
|
||||
return s
|
||||
}
|
||||
}
|
||||
if l == cap(s) {
|
||||
s1 := make([]state, 2*l)[0:l];
|
||||
for i := 0; i < l; i++ {
|
||||
s1[i] = s[i];
|
||||
}
|
||||
s = s1;
|
||||
}
|
||||
s = s[0:l+1];
|
||||
s[l].inst = inst;
|
||||
s[l].match = match;
|
||||
return s;
|
||||
}
|
||||
|
||||
func (re *Regexp) doExecute(str string, pos int) []int {
|
||||
var s [2][]state; // TODO: use a vector when state values (not ptrs) can be vector elements
|
||||
s[0] = make([]state, 10)[0:0];
|
||||
s[1] = make([]state, 10)[0:0];
|
||||
in, out := 0, 1;
|
||||
var final state;
|
||||
found := false;
|
||||
for pos <= len(str) {
|
||||
if !found {
|
||||
// prime the pump if we haven't seen a match yet
|
||||
match := make([]int, 2*(re.nbra+1));
|
||||
for i := 0; i < len(match); i++ {
|
||||
match[i] = -1; // no match seen; catches cases like "a(b)?c" on "ac"
|
||||
}
|
||||
match[0] = pos;
|
||||
s[out] = addState(s[out], re.start.next(), match);
|
||||
}
|
||||
in, out = out, in; // old out state is new in state
|
||||
s[out] = s[out][0:0]; // clear out state
|
||||
if len(s[in]) == 0 {
|
||||
// machine has completed
|
||||
break;
|
||||
}
|
||||
charwidth := 1;
|
||||
c := endOfFile;
|
||||
if pos < len(str) {
|
||||
c, charwidth = utf8.DecodeRuneInString(str[pos:len(str)]);
|
||||
}
|
||||
for i := 0; i < len(s[in]); i++ {
|
||||
st := s[in][i];
|
||||
switch s[in][i].inst.kind() {
|
||||
case _BOT:
|
||||
if pos == 0 {
|
||||
s[in] = addState(s[in], st.inst.next(), st.match)
|
||||
}
|
||||
case _EOT:
|
||||
if pos == len(str) {
|
||||
s[in] = addState(s[in], st.inst.next(), st.match)
|
||||
}
|
||||
case _CHAR:
|
||||
if c == st.inst.(*_Char).char {
|
||||
s[out] = addState(s[out], st.inst.next(), st.match)
|
||||
}
|
||||
case _CHARCLASS:
|
||||
if st.inst.(*_CharClass).matches(c) {
|
||||
s[out] = addState(s[out], st.inst.next(), st.match)
|
||||
}
|
||||
case _ANY:
|
||||
if c != endOfFile {
|
||||
s[out] = addState(s[out], st.inst.next(), st.match)
|
||||
}
|
||||
case _BRA:
|
||||
n := st.inst.(*_Bra).n;
|
||||
st.match[2*n] = pos;
|
||||
s[in] = addState(s[in], st.inst.next(), st.match);
|
||||
case _EBRA:
|
||||
n := st.inst.(*_Ebra).n;
|
||||
st.match[2*n+1] = pos;
|
||||
s[in] = addState(s[in], st.inst.next(), st.match);
|
||||
case _ALT:
|
||||
s[in] = addState(s[in], st.inst.(*_Alt).left, st.match);
|
||||
// give other branch a copy of this match vector
|
||||
s1 := make([]int, 2*(re.nbra+1));
|
||||
for i := 0; i < len(s1); i++ {
|
||||
s1[i] = st.match[i]
|
||||
}
|
||||
s[in] = addState(s[in], st.inst.next(), s1);
|
||||
case _END:
|
||||
// choose leftmost longest
|
||||
if !found || // first
|
||||
st.match[0] < final.match[0] || // leftmost
|
||||
(st.match[0] == final.match[0] && pos > final.match[1]) { // longest
|
||||
final = st;
|
||||
final.match[1] = pos;
|
||||
}
|
||||
found = true;
|
||||
default:
|
||||
st.inst.print();
|
||||
panic("unknown instruction in execute");
|
||||
}
|
||||
}
|
||||
pos += charwidth;
|
||||
}
|
||||
return final.match;
|
||||
}
|
||||
|
||||
|
||||
// Execute matches the Regexp against the string s.
|
||||
// The return value is an array of integers, in pairs, identifying the positions of
|
||||
// substrings matched by the expression.
|
||||
// s[a[0]:a[1]] is the substring matched by the entire expression.
|
||||
// s[a[2*i]:a[2*i+1]] for i > 0 is the substring matched by the ith parenthesized subexpression.
|
||||
// A negative value means the subexpression did not match any element of the string.
|
||||
// An empty array means "no match".
|
||||
func (re *Regexp) Execute(s string) (a []int) {
|
||||
return re.doExecute(s, 0)
|
||||
}
|
||||
|
||||
|
||||
// Match returns whether the Regexp matches the string s.
|
||||
// The return value is a boolean: true for match, false for no match.
|
||||
func (re *Regexp) Match(s string) bool {
|
||||
return len(re.doExecute(s, 0)) > 0
|
||||
}
|
||||
|
||||
|
||||
// MatchStrings matches the Regexp against the string s.
|
||||
// The return value is an array of strings matched by the expression.
|
||||
// a[0] is the substring matched by the entire expression.
|
||||
// a[i] for i > 0 is the substring matched by the ith parenthesized subexpression.
|
||||
// An empty array means ``no match''.
|
||||
func (re *Regexp) MatchStrings(s string) (a []string) {
|
||||
r := re.doExecute(s, 0);
|
||||
if r == nil {
|
||||
return nil
|
||||
}
|
||||
a = make([]string, len(r)/2);
|
||||
for i := 0; i < len(r); i += 2 {
|
||||
if r[i] != -1 { // -1 means no match for this subexpression
|
||||
a[i/2] = s[r[i] : r[i+1]]
|
||||
}
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
// Match checks whether a textual regular expression
|
||||
// matches a substring. More complicated queries need
|
||||
// to use Compile and the full Regexp interface.
|
||||
func Match(pattern string, s string) (matched bool, error os.Error) {
|
||||
re, err := Compile(pattern);
|
||||
if err != nil {
|
||||
return false, err
|
||||
}
|
||||
return re.Match(s), nil
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue