mirror of
https://github.com/ceph/ceph-csi.git
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404 lines
9.4 KiB
Go
404 lines
9.4 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// TODO: remove hard-coded versions when we have implemented fractional weights.
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// The current implementation is incompatible with later CLDR versions.
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//go:generate go run maketables.go -cldr=23 -unicode=6.2.0
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// Package collate contains types for comparing and sorting Unicode strings
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// according to a given collation order.
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package collate // import "golang.org/x/text/collate"
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import (
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"bytes"
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"strings"
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"golang.org/x/text/internal/colltab"
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"golang.org/x/text/language"
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)
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// Collator provides functionality for comparing strings for a given
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// collation order.
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type Collator struct {
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options
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sorter sorter
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_iter [2]iter
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}
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func (c *Collator) iter(i int) *iter {
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// TODO: evaluate performance for making the second iterator optional.
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return &c._iter[i]
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}
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// Supported returns the list of languages for which collating differs from its parent.
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func Supported() []language.Tag {
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// TODO: use language.Coverage instead.
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t := make([]language.Tag, len(tags))
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copy(t, tags)
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return t
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}
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func init() {
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ids := strings.Split(availableLocales, ",")
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tags = make([]language.Tag, len(ids))
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for i, s := range ids {
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tags[i] = language.Raw.MustParse(s)
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}
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}
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var tags []language.Tag
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// New returns a new Collator initialized for the given locale.
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func New(t language.Tag, o ...Option) *Collator {
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index := colltab.MatchLang(t, tags)
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c := newCollator(getTable(locales[index]))
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// Set options from the user-supplied tag.
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c.setFromTag(t)
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// Set the user-supplied options.
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c.setOptions(o)
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c.init()
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return c
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}
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// NewFromTable returns a new Collator for the given Weighter.
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func NewFromTable(w colltab.Weighter, o ...Option) *Collator {
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c := newCollator(w)
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c.setOptions(o)
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c.init()
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return c
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}
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func (c *Collator) init() {
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if c.numeric {
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c.t = colltab.NewNumericWeighter(c.t)
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}
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c._iter[0].init(c)
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c._iter[1].init(c)
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}
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// Buffer holds keys generated by Key and KeyString.
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type Buffer struct {
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buf [4096]byte
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key []byte
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}
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func (b *Buffer) init() {
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if b.key == nil {
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b.key = b.buf[:0]
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}
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}
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// Reset clears the buffer from previous results generated by Key and KeyString.
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func (b *Buffer) Reset() {
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b.key = b.key[:0]
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}
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// Compare returns an integer comparing the two byte slices.
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// The result will be 0 if a==b, -1 if a < b, and +1 if a > b.
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func (c *Collator) Compare(a, b []byte) int {
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// TODO: skip identical prefixes once we have a fast way to detect if a rune is
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// part of a contraction. This would lead to roughly a 10% speedup for the colcmp regtest.
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c.iter(0).SetInput(a)
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c.iter(1).SetInput(b)
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if res := c.compare(); res != 0 {
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return res
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}
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if !c.ignore[colltab.Identity] {
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return bytes.Compare(a, b)
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}
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return 0
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}
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// CompareString returns an integer comparing the two strings.
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// The result will be 0 if a==b, -1 if a < b, and +1 if a > b.
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func (c *Collator) CompareString(a, b string) int {
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// TODO: skip identical prefixes once we have a fast way to detect if a rune is
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// part of a contraction. This would lead to roughly a 10% speedup for the colcmp regtest.
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c.iter(0).SetInputString(a)
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c.iter(1).SetInputString(b)
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if res := c.compare(); res != 0 {
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return res
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}
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if !c.ignore[colltab.Identity] {
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if a < b {
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return -1
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} else if a > b {
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return 1
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}
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}
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return 0
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}
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func compareLevel(f func(i *iter) int, a, b *iter) int {
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a.pce = 0
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b.pce = 0
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for {
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va := f(a)
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vb := f(b)
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if va != vb {
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if va < vb {
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return -1
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}
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return 1
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} else if va == 0 {
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break
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}
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}
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return 0
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}
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func (c *Collator) compare() int {
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ia, ib := c.iter(0), c.iter(1)
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// Process primary level
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if c.alternate != altShifted {
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// TODO: implement script reordering
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if res := compareLevel((*iter).nextPrimary, ia, ib); res != 0 {
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return res
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}
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} else {
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// TODO: handle shifted
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}
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if !c.ignore[colltab.Secondary] {
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f := (*iter).nextSecondary
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if c.backwards {
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f = (*iter).prevSecondary
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}
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if res := compareLevel(f, ia, ib); res != 0 {
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return res
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}
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}
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// TODO: special case handling (Danish?)
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if !c.ignore[colltab.Tertiary] || c.caseLevel {
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if res := compareLevel((*iter).nextTertiary, ia, ib); res != 0 {
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return res
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}
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if !c.ignore[colltab.Quaternary] {
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if res := compareLevel((*iter).nextQuaternary, ia, ib); res != 0 {
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return res
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}
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}
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}
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return 0
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}
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// Key returns the collation key for str.
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// Passing the buffer buf may avoid memory allocations.
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// The returned slice will point to an allocation in Buffer and will remain
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// valid until the next call to buf.Reset().
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func (c *Collator) Key(buf *Buffer, str []byte) []byte {
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// See https://www.unicode.org/reports/tr10/#Main_Algorithm for more details.
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buf.init()
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return c.key(buf, c.getColElems(str))
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}
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// KeyFromString returns the collation key for str.
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// Passing the buffer buf may avoid memory allocations.
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// The returned slice will point to an allocation in Buffer and will retain
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// valid until the next call to buf.ResetKeys().
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func (c *Collator) KeyFromString(buf *Buffer, str string) []byte {
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// See https://www.unicode.org/reports/tr10/#Main_Algorithm for more details.
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buf.init()
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return c.key(buf, c.getColElemsString(str))
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}
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func (c *Collator) key(buf *Buffer, w []colltab.Elem) []byte {
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processWeights(c.alternate, c.t.Top(), w)
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kn := len(buf.key)
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c.keyFromElems(buf, w)
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return buf.key[kn:]
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}
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func (c *Collator) getColElems(str []byte) []colltab.Elem {
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i := c.iter(0)
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i.SetInput(str)
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for i.Next() {
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}
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return i.Elems
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}
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func (c *Collator) getColElemsString(str string) []colltab.Elem {
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i := c.iter(0)
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i.SetInputString(str)
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for i.Next() {
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}
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return i.Elems
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}
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type iter struct {
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wa [512]colltab.Elem
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colltab.Iter
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pce int
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}
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func (i *iter) init(c *Collator) {
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i.Weighter = c.t
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i.Elems = i.wa[:0]
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}
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func (i *iter) nextPrimary() int {
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for {
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for ; i.pce < i.N; i.pce++ {
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if v := i.Elems[i.pce].Primary(); v != 0 {
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i.pce++
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return v
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}
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}
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if !i.Next() {
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return 0
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}
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}
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panic("should not reach here")
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}
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func (i *iter) nextSecondary() int {
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for ; i.pce < len(i.Elems); i.pce++ {
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if v := i.Elems[i.pce].Secondary(); v != 0 {
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i.pce++
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return v
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}
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}
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return 0
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}
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func (i *iter) prevSecondary() int {
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for ; i.pce < len(i.Elems); i.pce++ {
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if v := i.Elems[len(i.Elems)-i.pce-1].Secondary(); v != 0 {
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i.pce++
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return v
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}
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}
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return 0
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}
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func (i *iter) nextTertiary() int {
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for ; i.pce < len(i.Elems); i.pce++ {
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if v := i.Elems[i.pce].Tertiary(); v != 0 {
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i.pce++
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return int(v)
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}
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}
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return 0
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}
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func (i *iter) nextQuaternary() int {
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for ; i.pce < len(i.Elems); i.pce++ {
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if v := i.Elems[i.pce].Quaternary(); v != 0 {
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i.pce++
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return v
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}
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}
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return 0
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}
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func appendPrimary(key []byte, p int) []byte {
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// Convert to variable length encoding; supports up to 23 bits.
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if p <= 0x7FFF {
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key = append(key, uint8(p>>8), uint8(p))
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} else {
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key = append(key, uint8(p>>16)|0x80, uint8(p>>8), uint8(p))
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}
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return key
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}
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// keyFromElems converts the weights ws to a compact sequence of bytes.
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// The result will be appended to the byte buffer in buf.
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func (c *Collator) keyFromElems(buf *Buffer, ws []colltab.Elem) {
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for _, v := range ws {
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if w := v.Primary(); w > 0 {
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buf.key = appendPrimary(buf.key, w)
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}
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}
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if !c.ignore[colltab.Secondary] {
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buf.key = append(buf.key, 0, 0)
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// TODO: we can use one 0 if we can guarantee that all non-zero weights are > 0xFF.
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if !c.backwards {
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for _, v := range ws {
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if w := v.Secondary(); w > 0 {
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buf.key = append(buf.key, uint8(w>>8), uint8(w))
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}
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}
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} else {
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for i := len(ws) - 1; i >= 0; i-- {
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if w := ws[i].Secondary(); w > 0 {
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buf.key = append(buf.key, uint8(w>>8), uint8(w))
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}
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}
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}
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} else if c.caseLevel {
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buf.key = append(buf.key, 0, 0)
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}
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if !c.ignore[colltab.Tertiary] || c.caseLevel {
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buf.key = append(buf.key, 0, 0)
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for _, v := range ws {
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if w := v.Tertiary(); w > 0 {
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buf.key = append(buf.key, uint8(w))
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}
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}
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// Derive the quaternary weights from the options and other levels.
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// Note that we represent MaxQuaternary as 0xFF. The first byte of the
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// representation of a primary weight is always smaller than 0xFF,
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// so using this single byte value will compare correctly.
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if !c.ignore[colltab.Quaternary] && c.alternate >= altShifted {
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if c.alternate == altShiftTrimmed {
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lastNonFFFF := len(buf.key)
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buf.key = append(buf.key, 0)
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for _, v := range ws {
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if w := v.Quaternary(); w == colltab.MaxQuaternary {
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buf.key = append(buf.key, 0xFF)
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} else if w > 0 {
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buf.key = appendPrimary(buf.key, w)
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lastNonFFFF = len(buf.key)
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}
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}
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buf.key = buf.key[:lastNonFFFF]
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} else {
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buf.key = append(buf.key, 0)
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for _, v := range ws {
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if w := v.Quaternary(); w == colltab.MaxQuaternary {
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buf.key = append(buf.key, 0xFF)
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} else if w > 0 {
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buf.key = appendPrimary(buf.key, w)
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}
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}
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}
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}
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}
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}
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func processWeights(vw alternateHandling, top uint32, wa []colltab.Elem) {
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ignore := false
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vtop := int(top)
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switch vw {
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case altShifted, altShiftTrimmed:
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for i := range wa {
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if p := wa[i].Primary(); p <= vtop && p != 0 {
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wa[i] = colltab.MakeQuaternary(p)
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ignore = true
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} else if p == 0 {
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if ignore {
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wa[i] = colltab.Ignore
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}
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} else {
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ignore = false
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}
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}
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case altBlanked:
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for i := range wa {
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if p := wa[i].Primary(); p <= vtop && (ignore || p != 0) {
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wa[i] = colltab.Ignore
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ignore = true
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} else {
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ignore = false
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}
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}
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}
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}
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