Function EncodingHintByName

library/cpp/charset/codepage.cpp:357–394

};

ECharset EncodingHintByName(const char* encname) {
    if (!encname)
        return CODES_UNKNOWN; // safety check

    // Common trouble: spurious "charset=" in the encoding name
    if (!strnicmp(encname, "charset=", 8)) {
        encname += 8;
    }

    // Strip everything up to the first alphanumeric, and after the last one
    while (*encname && !isalnum(*encname))
        ++encname;

    if (!*encname)
        return CODES_UNKNOWN;

    const char* lastpos = encname + strlen(encname) - 1;
    while (lastpos > encname && !isalnum(*lastpos))
        --lastpos;

    // Do some normalization
    TString enc(encname, lastpos - encname + 1);
    enc.to_lower();
    for (char* p = enc.begin(); p != enc.end(); ++p) {
        if (*p == ' ' || *p == '=' || *p == '_')
            *p = '-';
    }

    NormalizeEncodingPrefixes(enc);

    ECharset hint = CharsetByName(enc.c_str());
    if (hint != CODES_UNKNOWN)
        return hint;

    if (Singleton<TEncodingNamesHashSet>()->Has(enc))
        return CODES_UNSUPPORTED;
    return CODES_UNKNOWN;
}