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