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// +build !windows
// +build !js
// +build !appengine
package runewidth
import (
"os"
"regexp"
"strings"
)
var reLoc = regexp.MustCompile(`^[a-z][a-z][a-z]?(?:_[A-Z][A-Z])?\.(.+)`)
var mblenTable = map[string]int{
"utf-8": 6,
"utf8": 6,
"jis": 8,
"eucjp": 3,
"euckr": 2,
"euccn": 2,
"sjis": 2,
"cp932": 2,
"cp51932": 2,
"cp936": 2,
"cp949": 2,
"cp950": 2,
"big5": 2,
"gbk": 2,
"gb2312": 2,
}
func isEastAsian(locale string) bool {
charset := strings.ToLower(locale)
r := reLoc.FindStringSubmatch(locale)
if len(r) == 2 {
charset = strings.ToLower(r[1])
}
if strings.HasSuffix(charset, "@cjk_narrow") {
return false
}
for pos, b := range []byte(charset) {
if b == '@' {
charset = charset[:pos]
break
}
}
max := 1
if m, ok := mblenTable[charset]; ok {
max = m
}
if max > 1 && (charset[0] != 'u' ||
strings.HasPrefix(locale, "ja") ||
strings.HasPrefix(locale, "ko") ||
strings.HasPrefix(locale, "zh")) {
return true
}
return false
}
// IsEastAsian return true if the current locale is CJK
func IsEastAsian() bool {
locale := os.Getenv("LC_CTYPE")
if locale == "" {
locale = os.Getenv("LANG")
}
// ignore C locale
if locale == "POSIX" || locale == "C" {
return false
}
if len(locale) > 1 && locale[0] == 'C' && (locale[1] == '.' || locale[1] == '-') {
return false
}
return isEastAsian(locale)
}
|
