GS1 128

[ghola]

I'm having a hard time figuring out what character i should be using for FNC1 (i'm trying to generate GS1 128 barcodes). Btw, is it even possible to generate such barcodes with his library?

[ghola]

I figured out it's 241 and it does work as long as i have it at the beginning of the barcode number (attempting to work with barcode type C here), but as soon as i move it somewhere in the middle of the barcode it complains about the length not being even. My use case requires me to use multiple FCN1 characters.

Maybe if i produce a barcode for each piece starting with FCN1 and then concatenate them? But i'm not sure that's even possible.

[nicolaasuni]

Can you provide some examples or test cases?

[ghola]

Sure, here's an attempt to produce a USPS barcode which fails with the above mentioned error.

$trackingCode = '9405510200864168997758';
$fiveDigitZip = '29651';
$FNC1 = chr(241);
$code = "{$FNC1}420{$fiveDigitZip}{$FNC1}{$trackingCode}";

$barcode = new C($code, -1, -40, '#000000');
$svgImage = $barcode->getSvgCode();

However changing the code from $code = "{$FNC1}420{$fiveDigitZip}{$FNC1}{$trackingCode}"; to $code = "{$FNC1}420{$fiveDigitZip}{$trackingCode}"; works.

The spec for the USPS barcode is from the Endicia documentation: http://www.endicia.com/tools-resources/harrys-hints/new-usps-tracking-barcodes . Using this generator from USPS http://generator.onbarcode.com/online-gs1-128-barcode-generator.aspx with the following code (420)29651(94)05510200864168997758 produces the correct barcode (the parans are used to delimit the AIs, but it's just a way to intrododuce the FNC1 as it goes right before the opening parans)

[ghola]

I managed to do it by hacking the code in the getCodeDataC method. It is producing the correct barcode, identical to the USPS one. Here's what i ended up with:

class TcLibGS1 extends C
{
    /**
     * Get the C code point array
     *
     * @param array  $code_data Array of codepoints to alter
     * @param string $code      Code to process
     * @param int    $len       Number of characters to process
     *
     * @retun array
     *
     * @throws BarcodeException in case of error
     */
    protected function getCodeDataC(&$code_data, $code, $len)
    {
        $codeFragments = explode(chr(241), $code);

        foreach ($codeFragments as $fragment) {
            if ((strlen($fragment) % 2) != 0) {
                throw new BarcodeException(
                    'Fragment length must be even. A fragment is the code between two FNC1 characters.'
                );
            }
        }

        $codeFragmentCount = count($codeFragments);

        for ($i = 0; $i < $codeFragmentCount; $i++) {
            $fragment = $codeFragments[$i];
            $len = strlen($fragment);

            for ($pos = 0; $pos < $len; $pos += 2) {
                $chrnum = $fragment[$pos] . $fragment[($pos + 1)];
                if (preg_match('/([0-9]{2})/', $chrnum) > 0) {
                    $code_data[] = intval($chrnum);
                } else {
                    throw new BarcodeException('Invalid character sequence');
                }
            }

            if ($codeFragmentCount != 1 && $i != $codeFragmentCount - 1) {
                $code_data[] = 102;
            }
        }
    }
}

The idea was to split the code by FNC1 and during the build of the $code_data, reinsert '102' where the FNC1 used to be (i followed this approach from the C::getCodeData method where i noticed how the first FNC1 is handled).

[nicolaasuni]

Thanks for reporting this issue.
I have just pushed a new version that should fix the problem.
Please let me know if this is working as expected.

[ghola]

Thanks for the quick responses. Yes, it works as expected. Will you be releasing a tagged version for it?

[nicolaasuni]

Yes, done:
1.15.2

[ghola]

Thank you!

[jasimalikhan]

Hi I am facing the following error, I am using the latest version of the library, but I don't know sometimes its working and sometimes its through the attached error. Please help me out and your help will be really apricated