Apply nl2br to a string except for the content of a given string (Useful for <pre> tags)

smart_nl2br.php

<?
function smart_nl2br($data, $opening_tag, $closing_tag) {
    $results = "";
    $closing_tag_length = strlen($closing_tag);
    while(($position_start = strpos($data, $opening_tag)) !== false) {
        $position_end = strpos($data, $closing_tag);
        $previous_data = substr($data, 0, $position_start);
        $tag_data = substr($data, $position_start, $position_end - $position_start + $closing_tag_length);
        $data = substr($data, $position_end + $closing_tag_length);
        $results = $results . nl2br($previous_data) . $tag_data;
    }
    return $results;
}
//usage: $results = smart_nl2br("Some string", "[code]", "[/code]");
//Testing code:
$data = "
    Lorem
    Impsum
    Dicto 
    Sit
[b]- Incluimos las librerias jquery y ajaxupload[/b]
[code]<script type=\"text/javascript\" src=\"jquery.js\"></script>
<script type=\"text/javascript\" src=\"ajaxupload.js\"></script></pre>
<p><strong>- Html</strong></p>
<pre class=\"brush:xml\"><div id=\"content\">
        <a href=\"javascript:;\" id=\"upload\">Subir Foto</a>
        <ul id=\"gallery\">
            <!-- Cargar Fotos -->
        </ul>
    </div>[/code]
[b]- Css[/b]
[code]<style type=\"text/css\">

    body{
        margin:0;
        padding:0;
        font:normal 12px Arial, Helvetica, sans-serif
    }
    #content{
        width:700px;
        margin:20px auto;
        height:550px;
        border:6px solid #F3F3F3;
        padding-top:10px;
        overflow-y:auto
    }
    #upload{
        padding:12px;
        font:bold 12px Arial, Helvetica, sans-serif;
        text-align:center;
        background:#f2f2f2;
        color:#3366cc;
        border:1px solid #ccc;
        width:150px;
        display:block;
        -moz-border-radius:5px;
        -webkit-border-radius:5px;
        margin:0 auto;
        text-decoration:none
    }
    #gallery{
        list-style:none;
        margin:20px 0 0 0;
        padding:0
    }
    #gallery li{
        display:block;
        float:left;
        width:155px;
        height:160px;
        background:#9AF099;
        border:1px solid #093;
        text-align:center;
        padding:6px 0;
        margin:5px 0 5px 14px
    }
    #gallery li img{
        width:145px;
        height:140px
    }

</style>[/code]
- El javascript donde creamos una instancia de la clase Ajaxupload para poder cargar nuestras imagenes.
[code]<script type=\"text/javascript\">
    $(document).ready(function(){

        var button = $('#upload'), interval;
        new AjaxUpload(button,{
            action: 'procesa.php',
            name: 'image',
            onSubmit : function(file, ext){
                // cambiar el texto del boton cuando se selecicione la imagen
                button.text('Subiendo');
                // desabilitar el boton
                this.disable();

                interval = window.setInterval(function(){
                    var text = button.text();
                    if (text.length < 11){
                        button.text(text + '.');
                    } else {
                        button.text('Subiendo');
                    }
                }, 200);
            },
            onComplete: function(file, response){
                button.text('Subir Foto');

                window.clearInterval(interval);

                // Habilitar boton otra vez
                this.enable();

                // Añadiendo las imagenes a mi lista

                if($('#gallery li').length == 0){
                    $('#gallery').html(response).fadeIn(\"fast\");
                    $('#gallery li').eq(0).hide().show(\"slow\");
                }else{
                    $('#gallery').prepend(response);
                    $('#gallery li').eq(0).hide().show(\"slow\");
                }
            }
        });

        // Listar  fotos que hay en mi tabla
        $(\"#gallery\").load(\"procesa.php?action=listFotos\");
    });

</script>[/code]";
    echo smart_nl2br($data, "[code]", "[/code]");
?>