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- // Copyright 2015 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.
-
- //NOTE(dan): I need this because the default PRECIS API does not allow a way to retrieve the casefolded version of strings.
- // See also: https://github.com/golang/go/issues/17386
-
- // the content of this file is taken wholesale from the proper PRECIS API:
- // https://github.com/golang/text/tree/master/secure/precis
-
- package irc
-
- import (
- "unicode"
- "unicode/utf8"
-
- "golang.org/x/text/secure/precis"
- "golang.org/x/text/transform"
- "golang.org/x/text/unicode/norm"
- )
-
- type nickAdditionalMapping struct {
- // TODO: This transformer needs to be stateless somehow…
- notStart bool
- prevSpace bool
- }
-
- func (t *nickAdditionalMapping) Reset() {
- t.prevSpace = false
- t.notStart = false
- }
-
- func (t *nickAdditionalMapping) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
- // RFC 7700 §2.1. Rules
- //
- // 2. Additional Mapping Rule: The additional mapping rule consists of
- // the following sub-rules.
- //
- // 1. Any instances of non-ASCII space MUST be mapped to ASCII
- // space (U+0020); a non-ASCII space is any Unicode code point
- // having a general category of "Zs", naturally with the
- // exception of U+0020.
- //
- // 2. Any instances of the ASCII space character at the beginning
- // or end of a nickname MUST be removed (e.g., "stpeter " is
- // mapped to "stpeter").
- //
- // 3. Interior sequences of more than one ASCII space character
- // MUST be mapped to a single ASCII space character (e.g.,
- // "St Peter" is mapped to "St Peter").
-
- for nSrc < len(src) {
- r, size := utf8.DecodeRune(src[nSrc:])
- if size == 0 { // Incomplete UTF-8 encoding
- if !atEOF {
- return nDst, nSrc, transform.ErrShortSrc
- }
- size = 1
- }
- if unicode.Is(unicode.Zs, r) {
- t.prevSpace = true
- } else {
- if t.prevSpace && t.notStart {
- dst[nDst] = ' '
- nDst += 1
- }
- if size != copy(dst[nDst:], src[nSrc:nSrc+size]) {
- nDst += size
- return nDst, nSrc, transform.ErrShortDst
- }
- nDst += size
- t.prevSpace = false
- t.notStart = true
- }
- nSrc += size
- }
- return nDst, nSrc, nil
- }
-
- var (
- NicknameProfile = precis.NewFreeform(
- precis.AdditionalMapping(func() transform.Transformer {
- return &nickAdditionalMapping{}
- }),
- precis.LowerCase(),
- precis.Norm(norm.NFKC),
- precis.DisallowEmpty,
- )
- )
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