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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"flag"
"fmt"
"log"
"os"
"regexp/syntax"
"runtime/pprof"
)
var maxState = flag.Int("m", 1e5, "maximum number of states to explore")
var cpuprof = flag.String("cpuprofile", "", "cpu profile file")
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "usage: regmerge [-m maxstate] regexp [regexp2 regexp3....]\n")
os.Exit(2)
}
flag.Parse()
if len(flag.Args()) < 1 {
flag.Usage()
}
os.Exit(run(flag.Args()))
}
func run(args []string) int {
if *cpuprof != "" {
f, err := os.Create(*cpuprof)
if err != nil {
log.Fatal(err)
}
pprof.StartCPUProfile(f)
defer pprof.StopCPUProfile()
}
m, err := compile(flag.Args()...)
if err != nil {
log.Fatal(err)
}
n := 100
for ;; n *= 2 {
if n >= *maxState {
if n >= 2* *maxState {
fmt.Printf("reached state limit\n")
return 1
}
n = *maxState
}
log.Printf("try %d states...\n", n)
s, err := m.findMatch(n)
if err == nil {
fmt.Printf("%q\n", s)
return 0
}
if err != ErrMemory {
fmt.Printf("failed: %s\n", err)
return 3
}
}
panic("unreachable")
}
func compile(exprs ...string) (*matcher, error) {
var progs []*syntax.Prog
for _, expr := range exprs {
re, err := syntax.Parse(expr, syntax.Perl)
if err != nil {
return nil, err
}
sre := re.Simplify()
prog, err := syntax.Compile(sre)
if err != nil {
return nil, err
}
if err := toByteProg(prog); err != nil {
return nil, err
}
progs = append(progs, prog)
}
m := &matcher{}
if err := m.init(joinProgs(progs), len(progs)); err != nil {
return nil, err
}
return m, nil
}
func bug() {
panic("regmerge: internal error")
}
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