repo_zf1/documentation/manual/en/module_specs/Zend_Validate-Barcode.xml

<?xml version="1.0" encoding="UTF-8"?>
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<sect2 id="zend.validate.set.barcode">
    <title>Barcode</title>

    <para>
        <classname>Zend_Validate_Barcode</classname> allows you to check if a given value can be
        represented as barcode.
    </para>

    <para>
        <classname>Zend_Validate_Barcode</classname> supports multiple barcode standards and can be
        extended with proprietary barcode implementations very easily. The following barcode
        standards are supported:
    </para>

    <itemizedlist>
        <listitem>
            <para>
                <emphasis>CODE25</emphasis>: Often called "two of five."
            </para>

            <para>
                This barcode has no length limitation, but it must contain an even amount of
                characters. It supports only digits, and the last digit can be an optional checksum
                which is calculated with modulo 10. This standard is used worldwide and common on
                the market.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>CODE39</emphasis>: CODE39 is one of the oldest available codes.
            </para>

            <para>
                This barcode has a variable length. It supports digits, alphabetical characters
                and 7 special characters. It can have an optional checksum which is calculated with
                modulo 43. This standard is used worldwide and common within the industry.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>CODE93</emphasis>: CODE93 is the successor of CODE39.
            </para>

            <para>
                This barcode has a variable length. It supports digits, alphabetical characters
                and 7 special characters. It has an checksum which is calculated with modulo 47 and
                contains 2 characters. This standard produces a denser code than CODE39 and is more
                secure.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>EAN8</emphasis>: EAN is the shortcut for "European Article Number".
            </para>

            <para>
                These barcodes must have a length of 8 characters. It supports only digits, and
                the last digit is always a checksum. This standard is used worldwide but has a very
                limited range. It can be found on small articles where a longer barcode could not
                be printed.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>EAN12</emphasis>: EAN is the shortcut for "European Article Number".
            </para>

            <para>
                This barcode must have a length of 12 characters. It supports only digits, and the
                last digit is always a checksum which is calculated with modulo 10. This standard is
                used within the USA and common on the market. It has been superceded by EAN13.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>EAN13</emphasis>: EAN is the shortcut for "European Article Number".
            </para>

            <para>
                This barcode must have a length of 13 characters. It supports only digits, and the
                last digit is always a checksum which is calculated with modulo 10. This standard is
                used worldwide and common on the market.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>EAN14</emphasis>: EAN is the shortcut for "European Article Number".
            </para>

            <para>
                This barcode must have a length of 14 characters. It supports only digits, and the
                last digit is always a checksum which is calculated with modulo 10. This standard is
                used worldwide and common on the market. It is the successor for EAN13.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>GTIN12</emphasis>: GTIN is the shortcut for "Global Trade Item Number".
            </para>

            <para>
                This barcode uses the same standard as EAN12 and is its successor. It's commonly
                used within the USA.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>GTIN13</emphasis>: GTIN is the shortcut for "Global Trade Item Number".
            </para>

            <para>
                This barcode uses the same standard as EAN13 and is its successor. It is used
                worldwide by industry.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>GTIN14</emphasis>: GTIN is the shortcut for "Global Trade Item Number".
            </para>

            <para>
                This barcode uses the same standard as EAN14 and is its successor. It is used
                worldwide and common on the market.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>ITF14</emphasis>: ITF14 is the GS1 implementation of an Interleaved Two
                of Five bar code.
            </para>

            <para>
                This barcode is a special variant of Interleaved 2 of 5. It must have a length of
                14 characters and is based on GTIN14. It supports only digits, and the last digit
                must be a checksum digit which is calculated with modulo 10. It is used worldwide
                and common within the market.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>SSCC</emphasis>: SSCC is the shortcut for "Serial Shipping Container
                Code".
            </para>

            <para>
                This barcode is a variant of EAN barcode. It must have a length of 18 characters and
                supports only digits. The last digit must be a checksum digit which is calculated
                with modulo 10. It is commonly used by the transport industry.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>UPCA</emphasis>: UPC is the shortcut for "Univeral Product Code".
            </para>

            <para>
                This barcode preceeded EAN13. It must have a length of 12 characters and supports
                only digits. The last digit must be a checksum digit which is calculated with
                modulo 10. It is commonly used within the USA.
            </para>
        </listitem>

        <listitem>
            <para>
                <emphasis>UPCE</emphasis>: UPCE is the short variant from UPCA.
            </para>

            <para>
                This barcode is a smaller variant of UPCA. It must have a length of 6 characters and
                supports only digits. There is no checksum within this barcode. It is commonly used
                with small products where a UPCA barcode would not fit.
            </para>
        </listitem>
    </itemizedlist>

    <sect3 id="zend.validate.set.barcode.basic">
        <title>Basic usage</title>

        <para>
            To validate if a given string is a barcode you just need to know its type.  See the
            following example for an EAN13 barcode:
        </para>

        <programlisting language="php"><![CDATA[
$valid = new Zend_Validate_Barcode('EAN13');
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}
]]></programlisting>
    </sect3>

    <sect3 id="zend.validate.set.barcode.checksum">
        <title>Optional checksum</title>

        <para>
            Some barcodes can be provided with an optional checksum. These barcodes would be valid
            even without checksum. Still, when you provide a checksum, then you should also validate
            it. By default, these barcode types perform no checksum validation. By using the
            <property>checksum</property> option you can define if the checksum will be validated or
            ignored.
        </para>

        <programlisting language="php"><![CDATA[
$valid = new Zend_Validate_Barcode(array(
    'adapter'  => 'EAN13',
    'checksum' => false,
));
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}
]]></programlisting>

        <note>
            <title>Reduced security by disabling checksum validation</title>

            <para>
                 By switching off checksum validation you will also reduce the security of the used
                 barcodes. Additionally you should note that you can also turn off the checksum
                 validation for those barcode types which must contain a checksum value. Barcodes
                 which would not be valid could then be returned as valid even if they are not.
            </para>
        </note>
    </sect3>

    <sect3 id="zend.validate.set.barcode.custom">
        <title>Writing custom adapters</title>

        <para>
            You may write custom barcode validators for usage with
            <classname>Zend_Validate_Barcode</classname>; this is often necessary when dealing with
            proprietary barcode types.  To write your own barcode validator, you need the following
            information.
        </para>

        <itemizedlist>
            <listitem>
                <para>
                    <emphasis>Length</emphasis>: The length your barcode must have. It can have one
                    of the following values:
                </para>

                <itemizedlist>
                    <listitem>
                        <para>
                            <emphasis>Integer</emphasis>: A value greater 0, which means that the
                            barcode must have this length.
                        </para>
                    </listitem>

                    <listitem>
                        <para>
                            <emphasis>-1</emphasis>: There is no limitation for the length of this
                            barcode.
                        </para>
                    </listitem>

                    <listitem>
                        <para>
                            <emphasis>"even"</emphasis>: The length of this barcode must have a
                            even amount of digits.
                        </para>
                    </listitem>

                    <listitem>
                        <para>
                            <emphasis>"odd"</emphasis>: The length of this barcode must have a
                            odd amount of digits.
                        </para>
                    </listitem>

                    <listitem>
                        <para>
                            <emphasis>array</emphasis>: An array of integer values. The length of
                            this barcode must have one of the set array values.
                        </para>
                    </listitem>
                </itemizedlist>
            </listitem>

            <listitem>
                <para>
                    <emphasis>Characters</emphasis>: A string which contains all allowed characters
                    for this barcode. Also the integer value 128 is allowed, which means the first
                    128 characters of the ASCII table.
                </para>
            </listitem>

            <listitem>
                <para>
                    <emphasis>Checksum</emphasis>: A string which will be used as callback for a
                    method which does the checksum validation.
                </para>
            </listitem>
        </itemizedlist>

        <para>
            Your custom barcode validator must extend
            <classname>Zend_Validate_Barcode_AdapterAbstract</classname> or implement
            <interface>Zend_Validate_Barcode_AdapterInterface</interface>.
        </para>

        <para>
            As an example, let's create a validator that expects an even number of characters that
            include all digits and the letters 'ABCDE', and which requires a checksum.
        </para>

        <programlisting language="php"><![CDATA[
class My_Barcode_MyBar extends Zend_Validate_Barcode_AdapterAbstract
{
    protected $_length     = 'even';
    protected $_characters = '0123456789ABCDE';
    protected $_checksum   = '_mod66';

    protected function _mod66($barcode)
    {
        // do some validations and return a boolean
    }
}

$valid = new Zend_Validate_Barcode('My_Barcode_MyBar');
if ($valid->isValid($input)) {
    // input appears to be valid
} else {
    // input is invalid
}
]]></programlisting>
    </sect3>
</sect2>
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