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|
package ucd
import (
"bufio"
"encoding/binary"
"encoding/hex"
"io"
"regexp"
"strings"
)
type CodePointRange struct {
From rune
To rune
}
type UnicodeData struct {
GeneralCategory map[string][]*CodePointRange
}
func ParseUnicodeData(r io.Reader, propValAliases *PropertyValueAliases) (*UnicodeData, error) {
gc2CPRange := map[string][]*CodePointRange{}
lastCPTo := rune(-1)
p := newParser(r)
for p.parse() {
if len(p.fields) == 0 {
continue
}
cpFrom, cpTo, err := parseCodePointRange(p.fields[0])
if err != nil {
return nil, err
}
if cpFrom-lastCPTo > 1 {
defaultGCVal := propValAliases.GeneralCategoryDefaultValue
gc2CPRange[defaultGCVal] = append(gc2CPRange[defaultGCVal], &CodePointRange{
From: lastCPTo + 1,
To: cpFrom - 1,
})
}
lastCPTo = cpTo
gc := NormalizeSymbolicValue(p.fields[2])
rs, ok := gc2CPRange[gc]
if ok {
r := rs[len(rs)-1]
if cpFrom-r.To == 1 {
r.To = cpTo
} else {
gc2CPRange[gc] = append(rs, &CodePointRange{
From: cpFrom,
To: cpTo,
})
}
} else {
gc2CPRange[gc] = []*CodePointRange{
{
From: cpFrom,
To: cpTo,
},
}
}
}
if p.err != nil {
return nil, p.err
}
if lastCPTo < propValAliases.GeneralCategoryDefaultRange.To {
defaultGCVal := propValAliases.GeneralCategoryDefaultValue
gc2CPRange[defaultGCVal] = append(gc2CPRange[defaultGCVal], &CodePointRange{
From: lastCPTo + 1,
To: propValAliases.GeneralCategoryDefaultRange.To,
})
}
return &UnicodeData{
GeneralCategory: gc2CPRange,
}, nil
}
type PropertyValueAliases struct {
GeneralCategory map[string]string
GeneralCategoryDefaultRange *CodePointRange
GeneralCategoryDefaultValue string
}
func ParsePropertyValueAliases(r io.Reader) (*PropertyValueAliases, error) {
catName2Abbs := map[string]string{}
var defaultGCCPRange *CodePointRange
var defaultGCVal string
p := newParser(r)
for p.parse() {
if len(p.fields) > 0 && p.fields[0] == "gc" {
catNameShort := NormalizeSymbolicValue(p.fields[1])
catNameLong := NormalizeSymbolicValue(p.fields[2])
catName2Abbs[catNameShort] = catNameShort
catName2Abbs[catNameLong] = catNameShort
for _, f := range p.fields[3:] {
catNameOther := NormalizeSymbolicValue(f)
catName2Abbs[catNameOther] = catNameShort
}
}
if len(p.defaultFields) > 0 && p.defaultFields[1] == "General_Category" {
cpFrom, cpTo, err := parseCodePointRange(p.defaultFields[0])
if err != nil {
return nil, err
}
defaultGCCPRange = &CodePointRange{
From: cpFrom,
To: cpTo,
}
defaultGCVal = NormalizeSymbolicValue(p.defaultFields[2])
}
}
if p.err != nil {
return nil, p.err
}
return &PropertyValueAliases{
GeneralCategory: catName2Abbs,
GeneralCategoryDefaultRange: defaultGCCPRange,
GeneralCategoryDefaultValue: defaultGCVal,
}, nil
}
var symValReplacer = strings.NewReplacer("_", "", "-", "", "\x20", "")
func NormalizeSymbolicValue(original string) string {
strings.Trim("", "")
v := strings.ToLower(symValReplacer.Replace(original))
if strings.HasPrefix(v, "is") && v != "is" {
return v[3:]
}
return v
}
type Fields []string
var (
reLine = regexp.MustCompile(`^\s*(.*?)\s*(#.*)?$`)
reCodePointRange = regexp.MustCompile(`^([[:xdigit:]]+)(?:..([[:xdigit:]]+))?$`)
specialCommentPrefix = "# @missing:"
)
// This parser can parse data files of Unicode Character Database (UCD).
// Specifically, it has the following two functions:
// - Converts each line of the data files into a slice of fields.
// - Recognizes specially-formatted comments starting `@missing` and generates a slice of fields.
//
// However, for practical purposes, each field needs to be analyzed more specifically.
// For instance, in UnicodeData.txt, the first field represents a range of code points,
// so it needs to be recognized as a hexadecimal string.
// You can perform more specific parsing for each file by implementing a dedicated parser that wraps this parser.
//
// https://www.unicode.org/reports/tr44/#Format_Conventions
type parser struct {
scanner *bufio.Scanner
fields Fields
defaultFields Fields
err error
}
func newParser(r io.Reader) *parser {
return &parser{
scanner: bufio.NewScanner(r),
}
}
func (p *parser) parse() bool {
for p.scanner.Scan() {
p.fields, p.defaultFields, p.err = parseRecord(p.scanner.Text())
if p.err != nil {
return false
}
if p.fields != nil || p.defaultFields != nil {
return true
}
}
p.err = p.scanner.Err()
return false
}
func parseRecord(src string) (Fields, Fields, error) {
ms := reLine.FindStringSubmatch(src)
fields := ms[1]
comment := ms[2]
var fs Fields
if fields != "" {
fs = parseFields(fields)
}
var defaultFs Fields
if strings.HasPrefix(comment, specialCommentPrefix) {
fields := strings.Replace(comment, specialCommentPrefix, "", -1)
fs := parseFields(fields)
defaultFs = fs
}
return fs, defaultFs, nil
}
func parseFields(src string) Fields {
var fields Fields
for _, f := range strings.Split(src, ";") {
fields = append(fields, strings.TrimSpace(f))
}
return fields
}
func parseCodePointRange(src string) (rune, rune, error) {
var from, to rune
var err error
cp := reCodePointRange.FindStringSubmatch(src)
from, err = decodeHexToRune(cp[1])
if err != nil {
return 0, 0, err
}
if cp[2] != "" {
to, err = decodeHexToRune(cp[2])
if err != nil {
return 0, 0, err
}
} else {
to = from
}
return from, to, nil
}
func decodeHexToRune(hexCodePoint string) (rune, error) {
h := hexCodePoint
if len(h)%2 != 0 {
h = "0" + h
}
b, err := hex.DecodeString(h)
if err != nil {
return 0, err
}
l := len(b)
for i := 0; i < 4-l; i++ {
b = append([]byte{0}, b...)
}
n := binary.BigEndian.Uint32(b)
return rune(n), nil
}
|
