'Reliable' SMS Unicode & GSM Encoding in PHP

Question

(Updated a little)

I\'m not very experienced with internationalization using PHP, it must be said, and a deal of searching didn\'t really provide th

Answer 1

function is_gsm0338( $utf8_string ) {
    $gsm0338 = array(
        '@','Δ',' ','0','¡','P','¿','p',
        '£','_','!','1','A','Q','a','q',
        '$','Φ','"','2','B','R','b','r',
        '¥','Γ','#','3','C','S','c','s',
        'è','Λ','¤','4','D','T','d','t',
        'é','Ω','%','5','E','U','e','u',
        'ù','Π','&','6','F','V','f','v',
        'ì','Ψ','\'','7','G','W','g','w',
        'ò','Σ','(','8','H','X','h','x',
        'Ç','Θ',')','9','I','Y','i','y',
        "\n",'Ξ','*',':','J','Z','j','z',
        'Ø',"\x1B",'+',';','K','Ä','k','ä',
        'ø','Æ',',','<','L','Ö','l','ö',
        "\r",'æ','-','=','M','Ñ','m','ñ',
        'Å','ß','.','>','N','Ü','n','ü',
        'å','É','/','?','O','§','o','à'
     );
    $len = mb_strlen( $utf8_string, 'UTF-8');

    for( $i=0; $i < $len; $i++)
        if (!in_array(mb_substr($utf8_string,$i,1,'UTF-8'), $gsm0338))
            return false;

    return true;
}