--- /dev/null
+// Copyright 2013 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.
+
+package cldr
+
+import (
+ "bufio"
+ "encoding/xml"
+ "errors"
+ "fmt"
+ "strconv"
+ "strings"
+ "unicode"
+ "unicode/utf8"
+)
+
+// RuleProcessor can be passed to Collator's Process method, which
+// parses the rules and calls the respective method for each rule found.
+type RuleProcessor interface {
+ Reset(anchor string, before int) error
+ Insert(level int, str, context, extend string) error
+ Index(id string)
+}
+
+const (
+ // cldrIndex is a Unicode-reserved sentinel value used to mark the start
+ // of a grouping within an index.
+ // We ignore any rule that starts with this rune.
+ // See http://unicode.org/reports/tr35/#Collation_Elements for details.
+ cldrIndex = "\uFDD0"
+
+ // specialAnchor is the format in which to represent logical reset positions,
+ // such as "first tertiary ignorable".
+ specialAnchor = "<%s/>"
+)
+
+// Process parses the rules for the tailorings of this collation
+// and calls the respective methods of p for each rule found.
+func (c Collation) Process(p RuleProcessor) (err error) {
+ if len(c.Cr) > 0 {
+ if len(c.Cr) > 1 {
+ return fmt.Errorf("multiple cr elements, want 0 or 1")
+ }
+ return processRules(p, c.Cr[0].Data())
+ }
+ if c.Rules.Any != nil {
+ return c.processXML(p)
+ }
+ return errors.New("no tailoring data")
+}
+
+// processRules parses rules in the Collation Rule Syntax defined in
+// http://www.unicode.org/reports/tr35/tr35-collation.html#Collation_Tailorings.
+func processRules(p RuleProcessor, s string) (err error) {
+ chk := func(s string, e error) string {
+ if err == nil {
+ err = e
+ }
+ return s
+ }
+ i := 0 // Save the line number for use after the loop.
+ scanner := bufio.NewScanner(strings.NewReader(s))
+ for ; scanner.Scan() && err == nil; i++ {
+ for s := skipSpace(scanner.Text()); s != "" && s[0] != '#'; s = skipSpace(s) {
+ level := 5
+ var ch byte
+ switch ch, s = s[0], s[1:]; ch {
+ case '&': // followed by <anchor> or '[' <key> ']'
+ if s = skipSpace(s); consume(&s, '[') {
+ s = chk(parseSpecialAnchor(p, s))
+ } else {
+ s = chk(parseAnchor(p, 0, s))
+ }
+ case '<': // sort relation '<'{1,4}, optionally followed by '*'.
+ for level = 1; consume(&s, '<'); level++ {
+ }
+ if level > 4 {
+ err = fmt.Errorf("level %d > 4", level)
+ }
+ fallthrough
+ case '=': // identity relation, optionally followed by *.
+ if consume(&s, '*') {
+ s = chk(parseSequence(p, level, s))
+ } else {
+ s = chk(parseOrder(p, level, s))
+ }
+ default:
+ chk("", fmt.Errorf("illegal operator %q", ch))
+ break
+ }
+ }
+ }
+ if chk("", scanner.Err()); err != nil {
+ return fmt.Errorf("%d: %v", i, err)
+ }
+ return nil
+}
+
+// parseSpecialAnchor parses the anchor syntax which is either of the form
+// ['before' <level>] <anchor>
+// or
+// [<label>]
+// The starting should already be consumed.
+func parseSpecialAnchor(p RuleProcessor, s string) (tail string, err error) {
+ i := strings.IndexByte(s, ']')
+ if i == -1 {
+ return "", errors.New("unmatched bracket")
+ }
+ a := strings.TrimSpace(s[:i])
+ s = s[i+1:]
+ if strings.HasPrefix(a, "before ") {
+ l, err := strconv.ParseUint(skipSpace(a[len("before "):]), 10, 3)
+ if err != nil {
+ return s, err
+ }
+ return parseAnchor(p, int(l), s)
+ }
+ return s, p.Reset(fmt.Sprintf(specialAnchor, a), 0)
+}
+
+func parseAnchor(p RuleProcessor, level int, s string) (tail string, err error) {
+ anchor, s, err := scanString(s)
+ if err != nil {
+ return s, err
+ }
+ return s, p.Reset(anchor, level)
+}
+
+func parseOrder(p RuleProcessor, level int, s string) (tail string, err error) {
+ var value, context, extend string
+ if value, s, err = scanString(s); err != nil {
+ return s, err
+ }
+ if strings.HasPrefix(value, cldrIndex) {
+ p.Index(value[len(cldrIndex):])
+ return
+ }
+ if consume(&s, '|') {
+ if context, s, err = scanString(s); err != nil {
+ return s, errors.New("missing string after context")
+ }
+ }
+ if consume(&s, '/') {
+ if extend, s, err = scanString(s); err != nil {
+ return s, errors.New("missing string after extension")
+ }
+ }
+ return s, p.Insert(level, value, context, extend)
+}
+
+// scanString scans a single input string.
+func scanString(s string) (str, tail string, err error) {
+ if s = skipSpace(s); s == "" {
+ return s, s, errors.New("missing string")
+ }
+ buf := [16]byte{} // small but enough to hold most cases.
+ value := buf[:0]
+ for s != "" {
+ if consume(&s, '\'') {
+ i := strings.IndexByte(s, '\'')
+ if i == -1 {
+ return "", "", errors.New(`unmatched single quote`)
+ }
+ if i == 0 {
+ value = append(value, '\'')
+ } else {
+ value = append(value, s[:i]...)
+ }
+ s = s[i+1:]
+ continue
+ }
+ r, sz := utf8.DecodeRuneInString(s)
+ if unicode.IsSpace(r) || strings.ContainsRune("&<=#", r) {
+ break
+ }
+ value = append(value, s[:sz]...)
+ s = s[sz:]
+ }
+ return string(value), skipSpace(s), nil
+}
+
+func parseSequence(p RuleProcessor, level int, s string) (tail string, err error) {
+ if s = skipSpace(s); s == "" {
+ return s, errors.New("empty sequence")
+ }
+ last := rune(0)
+ for s != "" {
+ r, sz := utf8.DecodeRuneInString(s)
+ s = s[sz:]
+
+ if r == '-' {
+ // We have a range. The first element was already written.
+ if last == 0 {
+ return s, errors.New("range without starter value")
+ }
+ r, sz = utf8.DecodeRuneInString(s)
+ s = s[sz:]
+ if r == utf8.RuneError || r < last {
+ return s, fmt.Errorf("invalid range %q-%q", last, r)
+ }
+ for i := last + 1; i <= r; i++ {
+ if err := p.Insert(level, string(i), "", ""); err != nil {
+ return s, err
+ }
+ }
+ last = 0
+ continue
+ }
+
+ if unicode.IsSpace(r) || unicode.IsPunct(r) {
+ break
+ }
+
+ // normal case
+ if err := p.Insert(level, string(r), "", ""); err != nil {
+ return s, err
+ }
+ last = r
+ }
+ return s, nil
+}
+
+func skipSpace(s string) string {
+ return strings.TrimLeftFunc(s, unicode.IsSpace)
+}
+
+// consumes returns whether the next byte is ch. If so, it gobbles it by
+// updating s.
+func consume(s *string, ch byte) (ok bool) {
+ if *s == "" || (*s)[0] != ch {
+ return false
+ }
+ *s = (*s)[1:]
+ return true
+}
+
+// The following code parses Collation rules of CLDR version 24 and before.
+
+var lmap = map[byte]int{
+ 'p': 1,
+ 's': 2,
+ 't': 3,
+ 'i': 5,
+}
+
+type rulesElem struct {
+ Rules struct {
+ Common
+ Any []*struct {
+ XMLName xml.Name
+ rule
+ } `xml:",any"`
+ } `xml:"rules"`
+}
+
+type rule struct {
+ Value string `xml:",chardata"`
+ Before string `xml:"before,attr"`
+ Any []*struct {
+ XMLName xml.Name
+ rule
+ } `xml:",any"`
+}
+
+var emptyValueError = errors.New("cldr: empty rule value")
+
+func (r *rule) value() (string, error) {
+ // Convert hexadecimal Unicode codepoint notation to a string.
+ s := charRe.ReplaceAllStringFunc(r.Value, replaceUnicode)
+ r.Value = s
+ if s == "" {
+ if len(r.Any) != 1 {
+ return "", emptyValueError
+ }
+ r.Value = fmt.Sprintf(specialAnchor, r.Any[0].XMLName.Local)
+ r.Any = nil
+ } else if len(r.Any) != 0 {
+ return "", fmt.Errorf("cldr: XML elements found in collation rule: %v", r.Any)
+ }
+ return r.Value, nil
+}
+
+func (r rule) process(p RuleProcessor, name, context, extend string) error {
+ v, err := r.value()
+ if err != nil {
+ return err
+ }
+ switch name {
+ case "p", "s", "t", "i":
+ if strings.HasPrefix(v, cldrIndex) {
+ p.Index(v[len(cldrIndex):])
+ return nil
+ }
+ if err := p.Insert(lmap[name[0]], v, context, extend); err != nil {
+ return err
+ }
+ case "pc", "sc", "tc", "ic":
+ level := lmap[name[0]]
+ for _, s := range v {
+ if err := p.Insert(level, string(s), context, extend); err != nil {
+ return err
+ }
+ }
+ default:
+ return fmt.Errorf("cldr: unsupported tag: %q", name)
+ }
+ return nil
+}
+
+// processXML parses the format of CLDR versions 24 and older.
+func (c Collation) processXML(p RuleProcessor) (err error) {
+ // Collation is generated and defined in xml.go.
+ var v string
+ for _, r := range c.Rules.Any {
+ switch r.XMLName.Local {
+ case "reset":
+ level := 0
+ switch r.Before {
+ case "primary", "1":
+ level = 1
+ case "secondary", "2":
+ level = 2
+ case "tertiary", "3":
+ level = 3
+ case "":
+ default:
+ return fmt.Errorf("cldr: unknown level %q", r.Before)
+ }
+ v, err = r.value()
+ if err == nil {
+ err = p.Reset(v, level)
+ }
+ case "x":
+ var context, extend string
+ for _, r1 := range r.Any {
+ v, err = r1.value()
+ switch r1.XMLName.Local {
+ case "context":
+ context = v
+ case "extend":
+ extend = v
+ }
+ }
+ for _, r1 := range r.Any {
+ if t := r1.XMLName.Local; t == "context" || t == "extend" {
+ continue
+ }
+ r1.rule.process(p, r1.XMLName.Local, context, extend)
+ }
+ default:
+ err = r.rule.process(p, r.XMLName.Local, "", "")
+ }
+ if err != nil {
+ return err
+ }
+ }
+ return nil
+}
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