// The LowerCase option defines a Profile's case mapping rule. Options can be
// provided to determine the type of case folding used.
func LowerCase(opts ...cases.Option) Option {
return func(o *options) {
if len(opts) == 0 {
o.cases = cases.Lower(language.Und, cases.HandleFinalSigma(false))
return
}
opts = append([]cases.Option{cases.HandleFinalSigma(false)}, opts...)
o.cases = cases.Lower(language.Und, opts...)
}
}
}
x := b.next & 1
if b.buf[x] == nil {
b.buf[x] = make([]byte, 0, 8+len(b.src)+len(b.src)>>2)
}
span := append(b.buf[x][:0], b.src[:n]...)
b.src, _, err = transform.Append(t, span, b.src[n:])
b.buf[x] = b.src
b.next++
return err
}
// Pre-allocate transformers when possible. In some cases this avoids allocation.
var (
foldWidthT transform.SpanningTransformer = width.Fold
lowerCaseT transform.SpanningTransformer = cases.Lower(language.Und, cases.HandleFinalSigma(false))
)
// TODO: make this a method on profile.
func (b *buffers) enforce(p *Profile, src []byte, comparing bool) (str []byte, err error) {
b.src = src
ascii := true
for _, c := range src {
if c >= utf8.RuneSelf {
ascii = false
break
}
}
// ASCII fast path.
func (b *buffers) enforce(p *Profile, src []byte, comparing bool) (str []byte, err error) {
b.src = src
// These transforms are applied in the order defined in
// https://tools.ietf.org/html/rfc7564#section-7
// TODO: allow different width transforms options.
if p.options.foldWidth || (p.options.ignorecase && comparing) {
// TODO: use Span, once available.
if err = b.apply(width.Fold); err != nil {
return nil, err
}
}
for _, f := range p.options.additional {
if err = b.apply(f()); err != nil {
return nil, err
}
}
if p.options.cases != nil {
if err = b.apply(p.options.cases); err != nil {
return nil, err
}
}
if comparing && p.options.ignorecase {
if err = b.apply(cases.Lower(language.Und, cases.HandleFinalSigma(false))); err != nil {
return nil, err
}
}
if n := p.norm.QuickSpan(b.src); n < len(b.src) {
x := b.next & 1
n = copy(b.buf[x], b.src[:n])
b.src, _, err = transform.Append(p.norm, b.buf[x][:n], b.src[n:])
b.buf[x] = b.src
b.next++
if err != nil {
return nil, err
}
}
if p.options.bidiRule {
if err := b.apply(bidirule.New()); err != nil {
return nil, err
}
}
c := checker{p: p}
if _, err := c.span(b.src, true); err != nil {
return nil, err
}
if p.disallow != nil {
for i := 0; i < len(b.src); {
r, size := utf8.DecodeRune(b.src[i:])
if p.disallow.Contains(r) {
return nil, errDisallowedRune
}
i += size
}
}
// TODO: Add the disallow empty rule with a dummy transformer?
if p.options.disallowEmpty && len(b.src) == 0 {
return nil, errEmptyString
}
return b.src, nil
}