mirror of
https://github.com/autc04/Retro68.git
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1136 lines
34 KiB
Go
1136 lines
34 KiB
Go
// 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 regular expression search.
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//
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// The syntax of the regular expressions accepted is the same
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// general syntax used by Perl, Python, and other languages.
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// More precisely, it is the syntax accepted by RE2 and described at
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// https://golang.org/s/re2syntax, except for \C.
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// For an overview of the syntax, run
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// go doc regexp/syntax
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//
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// The regexp implementation provided by this package is
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// guaranteed to run in time linear in the size of the input.
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// (This is a property not guaranteed by most open source
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// implementations of regular expressions.) For more information
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// about this property, see
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// http://swtch.com/~rsc/regexp/regexp1.html
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// or any book about automata theory.
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//
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// All characters are UTF-8-encoded code points.
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//
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// There are 16 methods of Regexp that match a regular expression and identify
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// the matched text. Their names are matched by this regular expression:
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//
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// Find(All)?(String)?(Submatch)?(Index)?
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//
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// If 'All' is present, the routine matches successive non-overlapping
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// matches of the entire expression. Empty matches abutting a preceding
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// match are ignored. The return value is a slice containing the successive
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// return values of the corresponding non-'All' routine. These routines take
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// an extra integer argument, n; if n >= 0, the function returns at most n
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// matches/submatches.
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//
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// If 'String' is present, the argument is a string; otherwise it is a slice
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// of bytes; return values are adjusted as appropriate.
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//
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// If 'Submatch' is present, the return value is a slice identifying the
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// successive submatches of the expression. Submatches are matches of
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// parenthesized subexpressions (also known as capturing groups) within the
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// regular expression, numbered from left to right in order of opening
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// parenthesis. Submatch 0 is the match of the entire expression, submatch 1
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// the match of the first parenthesized subexpression, and so on.
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//
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// If 'Index' is present, matches and submatches are identified by byte index
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// pairs within the input string: result[2*n:2*n+1] identifies the indexes of
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// the nth submatch. The pair for n==0 identifies the match of the entire
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// expression. If 'Index' is not present, the match is identified by the
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// text of the match/submatch. If an index is negative, it means that
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// subexpression did not match any string in the input.
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//
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// There is also a subset of the methods that can be applied to text read
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// from a RuneReader:
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//
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// MatchReader, FindReaderIndex, FindReaderSubmatchIndex
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//
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// This set may grow. Note that regular expression matches may need to
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// examine text beyond the text returned by a match, so the methods that
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// match text from a RuneReader may read arbitrarily far into the input
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// before returning.
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//
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// (There are a few other methods that do not match this pattern.)
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//
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package regexp
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import (
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"bytes"
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"io"
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"regexp/syntax"
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"strconv"
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"strings"
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"sync"
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"unicode"
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"unicode/utf8"
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)
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var debug = false
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// Regexp is the representation of a compiled regular expression.
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// A Regexp is safe for concurrent use by multiple goroutines.
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type Regexp struct {
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// read-only after Compile
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expr string // as passed to Compile
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prog *syntax.Prog // compiled program
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onepass *onePassProg // onepass program or nil
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prefix string // required prefix in unanchored matches
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prefixBytes []byte // prefix, as a []byte
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prefixComplete bool // prefix is the entire regexp
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prefixRune rune // first rune in prefix
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prefixEnd uint32 // pc for last rune in prefix
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cond syntax.EmptyOp // empty-width conditions required at start of match
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numSubexp int
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subexpNames []string
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longest bool
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// cache of machines for running regexp
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mu sync.Mutex
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machine []*machine
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}
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// String returns the source text used to compile the regular expression.
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func (re *Regexp) String() string {
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return re.expr
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}
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// Copy returns a new Regexp object copied from re.
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//
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// When using a Regexp in multiple goroutines, giving each goroutine
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// its own copy helps to avoid lock contention.
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func (re *Regexp) Copy() *Regexp {
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r := *re
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r.mu = sync.Mutex{}
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r.machine = nil
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return &r
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}
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// Compile parses a regular expression and returns, if successful,
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// a Regexp object that can be used to match against text.
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//
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// When matching against text, the regexp returns a match that
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// begins as early as possible in the input (leftmost), and among those
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// it chooses the one that a backtracking search would have found first.
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// This so-called leftmost-first matching is the same semantics
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// that Perl, Python, and other implementations use, although this
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// package implements it without the expense of backtracking.
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// For POSIX leftmost-longest matching, see CompilePOSIX.
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func Compile(expr string) (*Regexp, error) {
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return compile(expr, syntax.Perl, false)
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}
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// CompilePOSIX is like Compile but restricts the regular expression
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// to POSIX ERE (egrep) syntax and changes the match semantics to
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// leftmost-longest.
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//
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// That is, when matching against text, the regexp returns a match that
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// begins as early as possible in the input (leftmost), and among those
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// it chooses a match that is as long as possible.
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// This so-called leftmost-longest matching is the same semantics
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// that early regular expression implementations used and that POSIX
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// specifies.
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//
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// However, there can be multiple leftmost-longest matches, with different
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// submatch choices, and here this package diverges from POSIX.
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// Among the possible leftmost-longest matches, this package chooses
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// the one that a backtracking search would have found first, while POSIX
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// specifies that the match be chosen to maximize the length of the first
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// subexpression, then the second, and so on from left to right.
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// The POSIX rule is computationally prohibitive and not even well-defined.
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// See http://swtch.com/~rsc/regexp/regexp2.html#posix for details.
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func CompilePOSIX(expr string) (*Regexp, error) {
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return compile(expr, syntax.POSIX, true)
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}
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// Longest makes future searches prefer the leftmost-longest match.
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// That is, when matching against text, the regexp returns a match that
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// begins as early as possible in the input (leftmost), and among those
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// it chooses a match that is as long as possible.
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func (re *Regexp) Longest() {
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re.longest = true
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}
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func compile(expr string, mode syntax.Flags, longest bool) (*Regexp, error) {
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re, err := syntax.Parse(expr, mode)
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if err != nil {
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return nil, err
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}
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maxCap := re.MaxCap()
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capNames := re.CapNames()
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re = re.Simplify()
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prog, err := syntax.Compile(re)
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if err != nil {
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return nil, err
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}
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regexp := &Regexp{
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expr: expr,
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prog: prog,
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onepass: compileOnePass(prog),
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numSubexp: maxCap,
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subexpNames: capNames,
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cond: prog.StartCond(),
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longest: longest,
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}
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if regexp.onepass == notOnePass {
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regexp.prefix, regexp.prefixComplete = prog.Prefix()
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} else {
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regexp.prefix, regexp.prefixComplete, regexp.prefixEnd = onePassPrefix(prog)
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}
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if regexp.prefix != "" {
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// TODO(rsc): Remove this allocation by adding
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// IndexString to package bytes.
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regexp.prefixBytes = []byte(regexp.prefix)
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regexp.prefixRune, _ = utf8.DecodeRuneInString(regexp.prefix)
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}
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return regexp, nil
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}
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// get returns a machine to use for matching re.
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// It uses the re's machine cache if possible, to avoid
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// unnecessary allocation.
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func (re *Regexp) get() *machine {
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re.mu.Lock()
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if n := len(re.machine); n > 0 {
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z := re.machine[n-1]
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re.machine = re.machine[:n-1]
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re.mu.Unlock()
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return z
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}
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re.mu.Unlock()
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z := progMachine(re.prog, re.onepass)
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z.re = re
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return z
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}
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// put returns a machine to the re's machine cache.
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// There is no attempt to limit the size of the cache, so it will
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// grow to the maximum number of simultaneous matches
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// run using re. (The cache empties when re gets garbage collected.)
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func (re *Regexp) put(z *machine) {
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re.mu.Lock()
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re.machine = append(re.machine, z)
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re.mu.Unlock()
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}
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// MustCompile is like Compile but panics if the expression cannot be parsed.
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// It simplifies safe initialization of global variables holding compiled regular
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// expressions.
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func MustCompile(str string) *Regexp {
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regexp, error := Compile(str)
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if error != nil {
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panic(`regexp: Compile(` + quote(str) + `): ` + error.Error())
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}
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return regexp
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}
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// MustCompilePOSIX is like CompilePOSIX but panics if the expression cannot be parsed.
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// It simplifies safe initialization of global variables holding compiled regular
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// expressions.
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func MustCompilePOSIX(str string) *Regexp {
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regexp, error := CompilePOSIX(str)
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if error != nil {
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panic(`regexp: CompilePOSIX(` + quote(str) + `): ` + error.Error())
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}
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return regexp
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}
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func quote(s string) string {
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if strconv.CanBackquote(s) {
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return "`" + s + "`"
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}
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return strconv.Quote(s)
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}
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// NumSubexp returns the number of parenthesized subexpressions in this Regexp.
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func (re *Regexp) NumSubexp() int {
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return re.numSubexp
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}
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// SubexpNames returns the names of the parenthesized subexpressions
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// in this Regexp. The name for the first sub-expression is names[1],
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// so that if m is a match slice, the name for m[i] is SubexpNames()[i].
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// Since the Regexp as a whole cannot be named, names[0] is always
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// the empty string. The slice should not be modified.
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func (re *Regexp) SubexpNames() []string {
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return re.subexpNames
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}
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const endOfText rune = -1
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// input abstracts different representations of the input text. It provides
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// one-character lookahead.
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type input interface {
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step(pos int) (r rune, width int) // advance one rune
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canCheckPrefix() bool // can we look ahead without losing info?
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hasPrefix(re *Regexp) bool
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index(re *Regexp, pos int) int
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context(pos int) syntax.EmptyOp
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}
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// inputString scans a string.
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type inputString struct {
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str string
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}
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func (i *inputString) step(pos int) (rune, int) {
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if pos < len(i.str) {
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c := i.str[pos]
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if c < utf8.RuneSelf {
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return rune(c), 1
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}
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return utf8.DecodeRuneInString(i.str[pos:])
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}
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return endOfText, 0
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}
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func (i *inputString) canCheckPrefix() bool {
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return true
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}
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func (i *inputString) hasPrefix(re *Regexp) bool {
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return strings.HasPrefix(i.str, re.prefix)
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}
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func (i *inputString) index(re *Regexp, pos int) int {
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return strings.Index(i.str[pos:], re.prefix)
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}
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func (i *inputString) context(pos int) syntax.EmptyOp {
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r1, r2 := endOfText, endOfText
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if pos > 0 && pos <= len(i.str) {
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r1, _ = utf8.DecodeLastRuneInString(i.str[:pos])
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}
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if pos < len(i.str) {
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r2, _ = utf8.DecodeRuneInString(i.str[pos:])
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}
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return syntax.EmptyOpContext(r1, r2)
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}
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// inputBytes scans a byte slice.
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type inputBytes struct {
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str []byte
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}
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func (i *inputBytes) step(pos int) (rune, int) {
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if pos < len(i.str) {
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c := i.str[pos]
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if c < utf8.RuneSelf {
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return rune(c), 1
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}
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return utf8.DecodeRune(i.str[pos:])
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}
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return endOfText, 0
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}
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func (i *inputBytes) canCheckPrefix() bool {
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return true
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}
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func (i *inputBytes) hasPrefix(re *Regexp) bool {
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return bytes.HasPrefix(i.str, re.prefixBytes)
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}
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func (i *inputBytes) index(re *Regexp, pos int) int {
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return bytes.Index(i.str[pos:], re.prefixBytes)
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}
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func (i *inputBytes) context(pos int) syntax.EmptyOp {
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r1, r2 := endOfText, endOfText
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if pos > 0 && pos <= len(i.str) {
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r1, _ = utf8.DecodeLastRune(i.str[:pos])
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}
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if pos < len(i.str) {
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r2, _ = utf8.DecodeRune(i.str[pos:])
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}
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return syntax.EmptyOpContext(r1, r2)
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}
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// inputReader scans a RuneReader.
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type inputReader struct {
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r io.RuneReader
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atEOT bool
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pos int
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}
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func (i *inputReader) step(pos int) (rune, int) {
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if !i.atEOT && pos != i.pos {
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return endOfText, 0
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}
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r, w, err := i.r.ReadRune()
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if err != nil {
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i.atEOT = true
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return endOfText, 0
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}
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i.pos += w
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return r, w
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}
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func (i *inputReader) canCheckPrefix() bool {
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return false
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}
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func (i *inputReader) hasPrefix(re *Regexp) bool {
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return false
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}
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func (i *inputReader) index(re *Regexp, pos int) int {
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return -1
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}
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func (i *inputReader) context(pos int) syntax.EmptyOp {
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return 0
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}
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// LiteralPrefix returns a literal string that must begin any match
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// of the regular expression re. It returns the boolean true if the
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// literal string comprises the entire regular expression.
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func (re *Regexp) LiteralPrefix() (prefix string, complete bool) {
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return re.prefix, re.prefixComplete
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}
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// MatchReader reports whether the Regexp matches the text read by the
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// RuneReader.
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func (re *Regexp) MatchReader(r io.RuneReader) bool {
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return re.doExecute(r, nil, "", 0, 0) != nil
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}
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// MatchString reports whether the Regexp matches the string s.
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func (re *Regexp) MatchString(s string) bool {
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return re.doExecute(nil, nil, s, 0, 0) != nil
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}
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// Match reports whether the Regexp matches the byte slice b.
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func (re *Regexp) Match(b []byte) bool {
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return re.doExecute(nil, b, "", 0, 0) != nil
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}
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// MatchReader checks whether a textual regular expression matches the text
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// read by the RuneReader. More complicated queries need to use Compile and
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// the full Regexp interface.
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func MatchReader(pattern string, r io.RuneReader) (matched bool, err error) {
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re, err := Compile(pattern)
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if err != nil {
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return false, err
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}
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return re.MatchReader(r), nil
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}
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// MatchString checks whether a textual regular expression
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// matches a string. More complicated queries need
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// to use Compile and the full Regexp interface.
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func MatchString(pattern string, s string) (matched bool, err error) {
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re, err := Compile(pattern)
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if err != nil {
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return false, err
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}
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return re.MatchString(s), nil
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}
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// Match checks whether a textual regular expression
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// matches a byte slice. More complicated queries need
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// to use Compile and the full Regexp interface.
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func Match(pattern string, b []byte) (matched bool, err error) {
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re, err := Compile(pattern)
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if err != nil {
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return false, err
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}
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return re.Match(b), nil
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}
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// ReplaceAllString returns a copy of src, replacing matches of the Regexp
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// with the replacement string repl. Inside repl, $ signs are interpreted as
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// in Expand, so for instance $1 represents the text of the first submatch.
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func (re *Regexp) ReplaceAllString(src, repl string) string {
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n := 2
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if strings.Index(repl, "$") >= 0 {
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n = 2 * (re.numSubexp + 1)
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}
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b := re.replaceAll(nil, src, n, func(dst []byte, match []int) []byte {
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return re.expand(dst, repl, nil, src, match)
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})
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return string(b)
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}
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// ReplaceAllLiteralString returns a copy of src, replacing matches of the Regexp
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// with the replacement string repl. The replacement repl is substituted directly,
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// without using Expand.
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func (re *Regexp) ReplaceAllLiteralString(src, repl string) string {
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return string(re.replaceAll(nil, src, 2, func(dst []byte, match []int) []byte {
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return append(dst, repl...)
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}))
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}
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// ReplaceAllStringFunc returns a copy of src in which all matches of the
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// Regexp have been replaced by the return value of function repl applied
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// to the matched substring. The replacement returned by repl is substituted
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// directly, without using Expand.
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func (re *Regexp) ReplaceAllStringFunc(src string, repl func(string) string) string {
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b := re.replaceAll(nil, src, 2, func(dst []byte, match []int) []byte {
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return append(dst, repl(src[match[0]:match[1]])...)
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})
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return string(b)
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}
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func (re *Regexp) replaceAll(bsrc []byte, src string, nmatch int, repl func(dst []byte, m []int) []byte) []byte {
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lastMatchEnd := 0 // end position of the most recent match
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searchPos := 0 // position where we next look for a match
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var buf []byte
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var endPos int
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if bsrc != nil {
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endPos = len(bsrc)
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} else {
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endPos = len(src)
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}
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if nmatch > re.prog.NumCap {
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nmatch = re.prog.NumCap
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}
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for searchPos <= endPos {
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a := re.doExecute(nil, bsrc, src, searchPos, nmatch)
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if len(a) == 0 {
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break // no more matches
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|
}
|
|
|
|
// Copy the unmatched characters before this match.
|
|
if bsrc != nil {
|
|
buf = append(buf, bsrc[lastMatchEnd:a[0]]...)
|
|
} else {
|
|
buf = append(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 {
|
|
buf = repl(buf, a)
|
|
}
|
|
lastMatchEnd = a[1]
|
|
|
|
// Advance past this match; always advance at least one character.
|
|
var width int
|
|
if bsrc != nil {
|
|
_, width = utf8.DecodeRune(bsrc[searchPos:])
|
|
} else {
|
|
_, 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.
|
|
if bsrc != nil {
|
|
buf = append(buf, bsrc[lastMatchEnd:]...)
|
|
} else {
|
|
buf = append(buf, src[lastMatchEnd:]...)
|
|
}
|
|
|
|
return buf
|
|
}
|
|
|
|
// ReplaceAll returns a copy of src, replacing matches of the Regexp
|
|
// with the replacement text repl. Inside repl, $ signs are interpreted as
|
|
// in Expand, so for instance $1 represents the text of the first submatch.
|
|
func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
|
|
n := 2
|
|
if bytes.IndexByte(repl, '$') >= 0 {
|
|
n = 2 * (re.numSubexp + 1)
|
|
}
|
|
srepl := ""
|
|
b := re.replaceAll(src, "", n, func(dst []byte, match []int) []byte {
|
|
if len(srepl) != len(repl) {
|
|
srepl = string(repl)
|
|
}
|
|
return re.expand(dst, srepl, src, "", match)
|
|
})
|
|
return b
|
|
}
|
|
|
|
// ReplaceAllLiteral returns a copy of src, replacing matches of the Regexp
|
|
// with the replacement bytes repl. The replacement repl is substituted directly,
|
|
// without using Expand.
|
|
func (re *Regexp) ReplaceAllLiteral(src, repl []byte) []byte {
|
|
return re.replaceAll(src, "", 2, func(dst []byte, match []int) []byte {
|
|
return append(dst, repl...)
|
|
})
|
|
}
|
|
|
|
// ReplaceAllFunc returns a copy of src in which all matches of the
|
|
// Regexp have been replaced by the return value of function repl applied
|
|
// to the matched byte slice. The replacement returned by repl is substituted
|
|
// directly, without using Expand.
|
|
func (re *Regexp) ReplaceAllFunc(src []byte, repl func([]byte) []byte) []byte {
|
|
return re.replaceAll(src, "", 2, func(dst []byte, match []int) []byte {
|
|
return append(dst, repl(src[match[0]:match[1]])...)
|
|
})
|
|
}
|
|
|
|
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])
|
|
}
|
|
|
|
// The number of capture values in the program may correspond
|
|
// to fewer capturing expressions than are in the regexp.
|
|
// For example, "(a){0}" turns into an empty program, so the
|
|
// maximum capture in the program is 0 but we need to return
|
|
// an expression for \1. Pad appends -1s to the slice a as needed.
|
|
func (re *Regexp) pad(a []int) []int {
|
|
if a == nil {
|
|
// No match.
|
|
return nil
|
|
}
|
|
n := (1 + re.numSubexp) * 2
|
|
for len(a) < n {
|
|
a = append(a, -1)
|
|
}
|
|
return a
|
|
}
|
|
|
|
// 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; {
|
|
matches := re.doExecute(nil, b, s, 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(re.pad(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(nil, 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(nil, 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(nil, nil, 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) (loc []int) {
|
|
a := re.doExecute(nil, nil, 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 text was found in the input stream at
|
|
// byte offset loc[0] through loc[1]-1.
|
|
// A return value of nil indicates no match.
|
|
func (re *Regexp) FindReaderIndex(r io.RuneReader) (loc []int) {
|
|
a := re.doExecute(r, nil, "", 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(nil, b, "", 0, re.prog.NumCap)
|
|
if a == nil {
|
|
return nil
|
|
}
|
|
ret := make([][]byte, 1+re.numSubexp)
|
|
for i := range ret {
|
|
if 2*i < len(a) && a[2*i] >= 0 {
|
|
ret[i] = b[a[2*i]:a[2*i+1]]
|
|
}
|
|
}
|
|
return ret
|
|
}
|
|
|
|
// Expand appends template to dst and returns the result; during the
|
|
// append, Expand replaces variables in the template with corresponding
|
|
// matches drawn from src. The match slice should have been returned by
|
|
// FindSubmatchIndex.
|
|
//
|
|
// In the template, a variable is denoted by a substring of the form
|
|
// $name or ${name}, where name is a non-empty sequence of letters,
|
|
// digits, and underscores. A purely numeric name like $1 refers to
|
|
// the submatch with the corresponding index; other names refer to
|
|
// capturing parentheses named with the (?P<name>...) syntax. A
|
|
// reference to an out of range or unmatched index or a name that is not
|
|
// present in the regular expression is replaced with an empty slice.
|
|
//
|
|
// In the $name form, name is taken to be as long as possible: $1x is
|
|
// equivalent to ${1x}, not ${1}x, and, $10 is equivalent to ${10}, not ${1}0.
|
|
//
|
|
// To insert a literal $ in the output, use $$ in the template.
|
|
func (re *Regexp) Expand(dst []byte, template []byte, src []byte, match []int) []byte {
|
|
return re.expand(dst, string(template), src, "", match)
|
|
}
|
|
|
|
// ExpandString is like Expand but the template and source are strings.
|
|
// It appends to and returns a byte slice in order to give the calling
|
|
// code control over allocation.
|
|
func (re *Regexp) ExpandString(dst []byte, template string, src string, match []int) []byte {
|
|
return re.expand(dst, template, nil, src, match)
|
|
}
|
|
|
|
func (re *Regexp) expand(dst []byte, template string, bsrc []byte, src string, match []int) []byte {
|
|
for len(template) > 0 {
|
|
i := strings.Index(template, "$")
|
|
if i < 0 {
|
|
break
|
|
}
|
|
dst = append(dst, template[:i]...)
|
|
template = template[i:]
|
|
if len(template) > 1 && template[1] == '$' {
|
|
// Treat $$ as $.
|
|
dst = append(dst, '$')
|
|
template = template[2:]
|
|
continue
|
|
}
|
|
name, num, rest, ok := extract(template)
|
|
if !ok {
|
|
// Malformed; treat $ as raw text.
|
|
dst = append(dst, '$')
|
|
template = template[1:]
|
|
continue
|
|
}
|
|
template = rest
|
|
if num >= 0 {
|
|
if 2*num+1 < len(match) && match[2*num] >= 0 {
|
|
if bsrc != nil {
|
|
dst = append(dst, bsrc[match[2*num]:match[2*num+1]]...)
|
|
} else {
|
|
dst = append(dst, src[match[2*num]:match[2*num+1]]...)
|
|
}
|
|
}
|
|
} else {
|
|
for i, namei := range re.subexpNames {
|
|
if name == namei && 2*i+1 < len(match) && match[2*i] >= 0 {
|
|
if bsrc != nil {
|
|
dst = append(dst, bsrc[match[2*i]:match[2*i+1]]...)
|
|
} else {
|
|
dst = append(dst, src[match[2*i]:match[2*i+1]]...)
|
|
}
|
|
break
|
|
}
|
|
}
|
|
}
|
|
}
|
|
dst = append(dst, template...)
|
|
return dst
|
|
}
|
|
|
|
// extract returns the name from a leading "$name" or "${name}" in str.
|
|
// If it is a number, extract returns num set to that number; otherwise num = -1.
|
|
func extract(str string) (name string, num int, rest string, ok bool) {
|
|
if len(str) < 2 || str[0] != '$' {
|
|
return
|
|
}
|
|
brace := false
|
|
if str[1] == '{' {
|
|
brace = true
|
|
str = str[2:]
|
|
} else {
|
|
str = str[1:]
|
|
}
|
|
i := 0
|
|
for i < len(str) {
|
|
rune, size := utf8.DecodeRuneInString(str[i:])
|
|
if !unicode.IsLetter(rune) && !unicode.IsDigit(rune) && rune != '_' {
|
|
break
|
|
}
|
|
i += size
|
|
}
|
|
if i == 0 {
|
|
// empty name is not okay
|
|
return
|
|
}
|
|
name = str[:i]
|
|
if brace {
|
|
if i >= len(str) || str[i] != '}' {
|
|
// missing closing brace
|
|
return
|
|
}
|
|
i++
|
|
}
|
|
|
|
// Parse number.
|
|
num = 0
|
|
for i := 0; i < len(name); i++ {
|
|
if name[i] < '0' || '9' < name[i] || num >= 1e8 {
|
|
num = -1
|
|
break
|
|
}
|
|
num = num*10 + int(name[i]) - '0'
|
|
}
|
|
// Disallow leading zeros.
|
|
if name[0] == '0' && len(name) > 1 {
|
|
num = -1
|
|
}
|
|
|
|
rest = str[i:]
|
|
ok = true
|
|
return
|
|
}
|
|
|
|
// 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.pad(re.doExecute(nil, 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(nil, nil, s, 0, re.prog.NumCap)
|
|
if a == nil {
|
|
return nil
|
|
}
|
|
ret := make([]string, 1+re.numSubexp)
|
|
for i := range ret {
|
|
if 2*i < len(a) && 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.pad(re.doExecute(nil, nil, 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.pad(re.doExecute(r, nil, "", 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
|
|
}
|
|
|
|
// Split slices s into substrings separated by the expression and returns a slice of
|
|
// the substrings between those expression matches.
|
|
//
|
|
// The slice returned by this method consists of all the substrings of s
|
|
// not contained in the slice returned by FindAllString. When called on an expression
|
|
// that contains no metacharacters, it is equivalent to strings.SplitN.
|
|
//
|
|
// Example:
|
|
// s := regexp.MustCompile("a*").Split("abaabaccadaaae", 5)
|
|
// // s: ["", "b", "b", "c", "cadaaae"]
|
|
//
|
|
// The count determines the number of substrings to return:
|
|
// n > 0: at most n substrings; the last substring will be the unsplit remainder.
|
|
// n == 0: the result is nil (zero substrings)
|
|
// n < 0: all substrings
|
|
func (re *Regexp) Split(s string, n int) []string {
|
|
|
|
if n == 0 {
|
|
return nil
|
|
}
|
|
|
|
if len(re.expr) > 0 && len(s) == 0 {
|
|
return []string{""}
|
|
}
|
|
|
|
matches := re.FindAllStringIndex(s, n)
|
|
strings := make([]string, 0, len(matches))
|
|
|
|
beg := 0
|
|
end := 0
|
|
for _, match := range matches {
|
|
if n > 0 && len(strings) >= n-1 {
|
|
break
|
|
}
|
|
|
|
end = match[0]
|
|
if match[1] != 0 {
|
|
strings = append(strings, s[beg:end])
|
|
}
|
|
beg = match[1]
|
|
}
|
|
|
|
if end != len(s) {
|
|
strings = append(strings, s[beg:])
|
|
}
|
|
|
|
return strings
|
|
}
|