Silly little cli celebration tool
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// +build !windows,!js
package runewidth
import (
"os"
"regexp"
"strings"
)
var reLoc = regexp.MustCompile(`^[a-z][a-z][a-z]?(?:_[A-Z][A-Z])?\.(.+)`)
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
}
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
}
}
mbc_max := 1
switch charset {
case "utf-8", "utf8":
mbc_max = 6
case "jis":
mbc_max = 8
case "eucjp":
mbc_max = 3
case "euckr", "euccn":
mbc_max = 2
case "sjis", "cp932", "cp51932", "cp936", "cp949", "cp950":
mbc_max = 2
case "big5":
mbc_max = 2
case "gbk", "gb2312":
mbc_max = 2
}
if mbc_max > 1 && (charset[0] != 'u' ||
strings.HasPrefix(locale, "ja") ||
strings.HasPrefix(locale, "ko") ||
strings.HasPrefix(locale, "zh")) {
return true
}
return false
}