'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

Although this is an old thread I recently had to solve a very similar problem and wanted to post my answer. The PHP code is somewhat simple. It starts with a painstakingly large array of GSM valid character codes in an array, then simply checks if the current character is in that array using the ord($string) function which returns the ascii value of the first character of the string passed. Here is the code I use to validate if a string is GSM worth.

    $valid_gsm_keycodes = Array(   
        0x0040, 0x0394, 0x0020, 0x0030, 0x00a1, 0x0050, 0x00bf, 0x0070,
        0x00a3, 0x005f, 0x0021, 0x0031, 0x0041, 0x0051, 0x0061, 0x0071,
        0x0024, 0x03a6, 0x0022, 0x0032, 0x0042, 0x0052, 0x0062, 0x0072,
        0x00a5, 0x0393, 0x0023, 0x0033, 0x0043, 0x0053, 0x0063, 0x0073,
        0x00e8, 0x039b, 0x00a4, 0x0034, 0x0035, 0x0044, 0x0054, 0x0064, 0x0074,
        0x00e9, 0x03a9, 0x0025, 0x0045, 0x0045, 0x0055, 0x0065, 0x0075,
        0x00f9, 0x03a0, 0x0026, 0x0036, 0x0046, 0x0056, 0x0066, 0x0076,
        0x00ec, 0x03a8, 0x0027, 0x0037, 0x0047, 0x0057, 0x0067, 0x0077, 
        0x00f2, 0x03a3, 0x0028, 0x0038, 0x0048, 0x0058, 0x0068, 0x0078,
        0x00c7, 0x0398, 0x0029, 0x0039, 0x0049, 0x0059, 0x0069, 0x0079,
        0x000a, 0x039e, 0x002a, 0x003a, 0x004a, 0x005a, 0x006a, 0x007a,
        0x00d8, 0x001b, 0x002b, 0x003b, 0x004b, 0x00c4, 0x006b, 0x00e4,
        0x00f8, 0x00c6, 0x002c, 0x003c, 0x004c, 0x00d6, 0x006c, 0x00f6,
        0x000d, 0x00e6, 0x002d, 0x003d, 0x004d, 0x00d1, 0x006d, 0x00f1,
        0x00c5, 0x00df, 0x002e, 0x003e, 0x004e, 0x00dc, 0x006e, 0x00fc,
        0x00e5, 0x00c9, 0x002f, 0x003f, 0x004f, 0x00a7, 0x006f, 0x00e0 );


        for($i = 0; $i < strlen($string); $i++) {
            if(!in_array($string[$i], $valid_gsm_keycodes)) return false;
        }

        return true;