shad-go/iprange/lex.go
2022-04-14 04:36:15 +03:00

86 lines
1.3 KiB
Go

//go:build !solution
package iprange
import (
"bytes"
"errors"
"log"
"strconv"
"unicode/utf8"
)
const eof = 0
type ipLex struct {
line []byte
peek rune
output AddressRangeList
err error
}
func (ip *ipLex) Lex(yylval *ipSymType) int {
for {
c := ip.next()
switch c {
case eof:
return eof
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
return ip.byte(c, yylval)
default:
return int(c)
}
}
}
func (ip *ipLex) byte(c rune, yylval *ipSymType) int {
add := func(b *bytes.Buffer, c rune) {
if _, err := b.WriteRune(c); err != nil {
log.Fatalf("WriteRune: %s", err)
}
}
var b bytes.Buffer
add(&b, c)
L:
for {
c = ip.next()
switch c {
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
add(&b, c)
default:
break L
}
}
if c != eof {
ip.peek = c
}
octet, err := strconv.ParseUint(b.String(), 10, 32)
if err != nil {
log.Printf("badly formatted octet")
return eof
}
yylval.num = byte(octet)
return num
}
func (ip *ipLex) next() rune {
if ip.peek != eof {
r := ip.peek
ip.peek = eof
return r
}
if len(ip.line) == 0 {
return eof
}
c, size := utf8.DecodeRune(ip.line)
ip.line = ip.line[size:]
if c == utf8.RuneError && size == 1 {
log.Print("invalid utf8")
return ip.next()
}
return c
}
func (ip *ipLex) Error(s string) {
ip.err = errors.New(s)
}