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ergo/vendor/github.com/ergochat/irc-go/ircmsg/userhost.go
2022-01-20 17:59:57 -05:00

62 lines
1.4 KiB
Go

// written by Daniel Oaks <daniel@danieloaks.net>
// released under the ISC license
package ircmsg
import (
"errors"
"strings"
)
var (
MalformedNUH = errors.New("NUH is malformed")
)
// NUH holds a parsed name!user@host source ("prefix") of an IRC message.
// The Name member will be either a nickname (in the case of a user-initiated
// message) or a server name (in the case of a server-initiated numeric,
// command, or NOTICE).
type NUH struct {
Name string
User string
Host string
}
// ParseNUH parses a NUH source of an IRC message into its constituent parts;
// name (nickname or server name), username, and hostname.
func ParseNUH(in string) (out NUH, err error) {
if len(in) == 0 {
return out, MalformedNUH
}
hostStart := strings.IndexByte(in, '@')
if hostStart != -1 {
out.Host = in[hostStart+1:]
in = in[:hostStart]
}
userStart := strings.IndexByte(in, '!')
if userStart != -1 {
out.User = in[userStart+1:]
in = in[:userStart]
}
out.Name = in
return
}
// Canonical returns the canonical string representation of the NUH.
func (nuh *NUH) Canonical() (result string) {
var out strings.Builder
out.Grow(len(nuh.Name) + len(nuh.User) + len(nuh.Host) + 2)
out.WriteString(nuh.Name)
if len(nuh.User) != 0 {
out.WriteByte('!')
out.WriteString(nuh.User)
}
if len(nuh.Host) != 0 {
out.WriteByte('@')
out.WriteString(nuh.Host)
}
return out.String()
}