mirror of https://github.com/prometheus/prometheus
130 lines
3.7 KiB
Go
130 lines
3.7 KiB
Go
// Copyright 2014 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.
|
|
|
|
//go:generate go run gen.go gen_trieval.go
|
|
|
|
// Package cases provides general and language-specific case mappers.
|
|
package cases
|
|
|
|
import (
|
|
"golang.org/x/text/language"
|
|
"golang.org/x/text/transform"
|
|
)
|
|
|
|
// References:
|
|
// - Unicode Reference Manual Chapter 3.13, 4.2, and 5.18.
|
|
// - http://www.unicode.org/reports/tr29/
|
|
// - http://www.unicode.org/Public/6.3.0/ucd/CaseFolding.txt
|
|
// - http://www.unicode.org/Public/6.3.0/ucd/SpecialCasing.txt
|
|
// - http://www.unicode.org/Public/6.3.0/ucd/DerivedCoreProperties.txt
|
|
// - http://www.unicode.org/Public/6.3.0/ucd/auxiliary/WordBreakProperty.txt
|
|
// - http://www.unicode.org/Public/6.3.0/ucd/auxiliary/WordBreakTest.txt
|
|
// - http://userguide.icu-project.org/transforms/casemappings
|
|
|
|
// TODO:
|
|
// - Case folding
|
|
// - Wide and Narrow?
|
|
// - Segmenter option for title casing.
|
|
// - ASCII fast paths
|
|
// - Encode Soft-Dotted property within trie somehow.
|
|
|
|
// A Caser transforms given input to a certain case. It implements
|
|
// transform.Transformer.
|
|
//
|
|
// A Caser may be stateful and should therefore not be shared between
|
|
// goroutines.
|
|
type Caser struct {
|
|
t transform.Transformer
|
|
}
|
|
|
|
// Bytes returns a new byte slice with the result of converting b to the case
|
|
// form implemented by c.
|
|
func (c Caser) Bytes(b []byte) []byte {
|
|
b, _, _ = transform.Bytes(c.t, b)
|
|
return b
|
|
}
|
|
|
|
// String returns a string with the result of transforming s to the case form
|
|
// implemented by c.
|
|
func (c Caser) String(s string) string {
|
|
s, _, _ = transform.String(c.t, s)
|
|
return s
|
|
}
|
|
|
|
// Reset resets the Caser to be reused for new input after a previous call to
|
|
// Transform.
|
|
func (c Caser) Reset() { c.t.Reset() }
|
|
|
|
// Transform implements the Transformer interface and transforms the given input
|
|
// to the case form implemented by c.
|
|
func (c Caser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
|
|
return c.t.Transform(dst, src, atEOF)
|
|
}
|
|
|
|
// Upper returns a Caser for language-specific uppercasing.
|
|
func Upper(t language.Tag, opts ...Option) Caser {
|
|
return Caser{makeUpper(t, getOpts(opts...))}
|
|
}
|
|
|
|
// Lower returns a Caser for language-specific lowercasing.
|
|
func Lower(t language.Tag, opts ...Option) Caser {
|
|
return Caser{makeLower(t, getOpts(opts...))}
|
|
}
|
|
|
|
// Title returns a Caser for language-specific title casing. It uses an
|
|
// approximation of the default Unicode Word Break algorithm.
|
|
func Title(t language.Tag, opts ...Option) Caser {
|
|
return Caser{makeTitle(t, getOpts(opts...))}
|
|
}
|
|
|
|
// Fold returns a Caser that implements Unicode case folding. The returned Caser
|
|
// is stateless and safe to use concurrently by multiple goroutines.
|
|
//
|
|
// Case folding does not normalize the input and may not preserve a normal form.
|
|
// Use the collate or search package for more convenient and linguistically
|
|
// sound comparisons. Use unicode/precis for string comparisons where security
|
|
// aspects are a concern.
|
|
func Fold(opts ...Option) Caser {
|
|
return Caser{makeFold(getOpts(opts...))}
|
|
}
|
|
|
|
// An Option is used to modify the behavior of a Caser.
|
|
type Option func(o *options)
|
|
|
|
var (
|
|
// NoLower disables the lowercasing of non-leading letters for a title
|
|
// caser.
|
|
NoLower Option = noLower
|
|
|
|
// Compact omits mappings in case folding for characters that would grow the
|
|
// input. (Unimplemented.)
|
|
Compact Option = compact
|
|
)
|
|
|
|
// TODO: option to preserve a normal form, if applicable?
|
|
|
|
type options struct {
|
|
noLower bool
|
|
simple bool
|
|
|
|
// TODO: segmenter, max ignorable, alternative versions, etc.
|
|
|
|
noFinalSigma bool // Only used for testing.
|
|
}
|
|
|
|
func getOpts(o ...Option) (res options) {
|
|
for _, f := range o {
|
|
f(&res)
|
|
}
|
|
return
|
|
}
|
|
|
|
func noLower(o *options) {
|
|
o.noLower = true
|
|
}
|
|
|
|
func compact(o *options) {
|
|
o.simple = true
|
|
}
|