xK/xS/irc.go

133 lines
2.8 KiB
Go
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2024-04-02 16:44:01 +02:00
package main
import (
"path/filepath"
"regexp"
"strings"
)
func ircToLower(c byte) byte {
switch c {
case '[':
return '{'
case ']':
return '}'
case '\\':
return '|'
case '~':
return '^'
}
if c >= 'A' && c <= 'Z' {
return c + ('a' - 'A')
}
return c
}
func ircToUpper(c byte) byte {
switch c {
case '{':
return '['
case '}':
return ']'
case '|':
return '\\'
case '^':
return '~'
}
if c >= 'a' && c <= 'z' {
return c - ('a' - 'A')
}
return c
}
// Convert identifier to a canonical form for case-insensitive comparisons.
// ircToUpper is used so that statically initialized maps can be in uppercase.
func ircToCanon(ident string) string {
var canon []byte
for _, c := range []byte(ident) {
canon = append(canon, ircToUpper(c))
}
return string(canon)
}
func ircEqual(s1, s2 string) bool {
return ircToCanon(s1) == ircToCanon(s2)
}
func ircFnmatch(pattern string, s string) bool {
pattern, s = ircToCanon(pattern), ircToCanon(s)
// FIXME: This should not support [] ranges and handle '/' specially.
// We could translate the pattern to a regular expression.
matched, _ := filepath.Match(pattern, s)
return matched
}
var reMsg = regexp.MustCompile(
`^(?:@([^ ]*) +)?(?::([^! ]*)(?:!([^@]*)@([^ ]*))? +)?([^ ]+)(.*)?$`)
var reArgs = regexp.MustCompile(`:.*| [^: ][^ ]*`)
type message struct {
tags map[string]string // IRC 3.2 message tags
nick string // optional nickname
user string // optional username
host string // optional hostname or IP address
command string // command name
params []string // arguments
}
func ircUnescapeMessageTag(value string) string {
var buf []byte
escape := false
for i := 0; i < len(value); i++ {
if escape {
switch value[i] {
case ':':
buf = append(buf, ';')
case 's':
buf = append(buf, ' ')
case 'r':
buf = append(buf, '\r')
case 'n':
buf = append(buf, '\n')
default:
buf = append(buf, value[i])
}
escape = false
} else if value[i] == '\\' {
escape = true
} else {
buf = append(buf, value[i])
}
}
return string(buf)
}
func ircParseMessageTags(tags string, out map[string]string) {
for _, tag := range strings.Split(tags, ";") {
if tag == "" {
// Ignore empty.
} else if equal := strings.IndexByte(tag, '='); equal < 0 {
out[tag] = ""
} else {
out[tag[:equal]] = ircUnescapeMessageTag(tag[equal+1:])
}
}
}
func ircParseMessage(line string) *message {
m := reMsg.FindStringSubmatch(line)
if m == nil {
return nil
}
msg := message{nil, m[2], m[3], m[4], m[5], nil}
if m[1] != "" {
msg.tags = make(map[string]string)
ircParseMessageTags(m[1], msg.tags)
}
for _, x := range reArgs.FindAllString(m[6], -1) {
msg.params = append(msg.params, x[1:])
}
return &msg
}