<?php
/*!
* @file bbcode.php
*
* A BBCode tag is defined in terms of two parameters, a parse type,
* and an argument count. The parse type, "type", is given by one of
* the TT_ constants.
*
* The argument count, "args", is in the range [0,4]. A zero-argument tag
* does not have an end tag. A one-argument tag has its argument between
* the start and end tag. A two-element tag is identical to a one-argument
* tag with the advent of an =arg1 in the opening tag, eg,
* [url=arg1]arg0[/url]
* A three-argument tag is given an additional parameter at tag close.
* A four-element tag actually has unlimited arguments and operates as
* an HTML tag. The parameters are passed in an associative array to
* a callback, which is the only valid type for this count.
*
* From an implementation perspective, the argument count controls how
* the tag is decomposed into memory, ie, parsed. The type determines
* how the tag is evaluated after parse finishes. The argument count is
* used in evaluation to pass the correct number of parameters, but the
* type is not considered during parse, at all.
*
* Other notes: Tag names may not contain spaces or "=".
*/
const TT_TRIVIAL = 0; ///< This tag is a direct HTML wrapper tag
const TT_INTERLEAVE = 1; ///< This tag becomes "html"[0] . arg0 . "html"[1] . arg1 ...
const TT_CALLBACK = 2; ///< This tag gets evaluated by a callback function
$bbtags = array(
'b' => array('type' => TT_TRIVIAL, 'args' => 1),
'i' => array('type' => TT_TRIVIAL, 'args' => 1),
'u' => array('type' => TT_TRIVIAL, 'args' => 1),
'hr' => array('type' => TT_TRIVIAL, 'args' => 0),
'img' => array(
'type' => TT_INTERLEAVE,
'args' => 1,
'html' => array('<img src="', '" alt="User image" />')
),
'url' => array(
'type' => TT_CALLBACK,
'args' => 2,
'func' => function($txt, $url) {
return '<a href="' . $url . '">' . $txt . '</a>';
}
),
'bubble' => array(
'type' => TT_CALLBACK,
'args' => 4,
'func' => function($txt, $args) {
$br = isset($args['radius'])? $args['radius'] : 6;
$col = isset($args['color'])? $args['color'] : "000";
return '<span class="bubble" style="'
. "border-radius:".$br."px;"
. "color:#".$col.";"
. '">' . $txt . '</span>';
}
),
'grad' => array(
'type' => TT_CALLBACK,
'args' => 3,
'func' => function($txt, $arg0, $arg1) {
if (empty($arg0)) $arg0="pink";
if (empty($arg1)) $arg1="green";
return "<span style=\"linear-gradient(to right,$arg0,$arg1)\">"
. $txt . '</span>';
}
)
);
function notice($s) { echo "<!-- Notice: $s -->\n"; }
/*!
* This is a recursive function; call it with i = 0, and it will
* call itself recursively until all tags are parsed. It returns the
* parsed string, with $i set to the position of the first-read closing tag.
* @param $str The string to parse.
* @param $i [in/out] The position from which to start parsing.
* Set at the end of the function to denote the first
* unparsed character, or FALSE if all characters have
* been consumed.
* @return Returns the HTML parsed substring of the given input.
*/
function parse_sub($str, &$i)
{
global $bbtags;
$outstr = "";
$bookmark = $i;
for ($i = strpos($str, '[', $i); $i !== FALSE; $i = strpos($str, '[', $i))
{
$close = strpos($str, ']', $i + 1);
if ($close == FALSE) {
$i = FALSE;
return $outstr . parse_nonbb(substr($str, $bookmark, $i - $bookmark));
}
// Look inside our tag, now
$stag = substr($str, $i+1, $close - $i - 1);
// If it's a closing tag, return and let the parent handle that
if ($stag[0] == '/')
return $outstr . parse_nonbb(substr($str, $bookmark, $i - $bookmark));
// Doplegänger
if ($stag[0] == '[') {
++$i;
continue;
}
// Make sure we're safe if args=1; we don't know, yet
$tagc = preg_split('/\s*[\s=]\s*/', $stag, 2);
if (count($tagc) == 2)
$arg1 = $tagc[1]; // This technically allows [tag x]y[/tag]
else
$arg1 = NULL; // Don't reuse old arg values
$tname = strtolower($tagc[0]); // Deliberately not trimmed
// Look up tag
$tstart = $i;
$i = $close + 1;
if (!array_key_exists($tname, $bbtags)) {
notice("No bbtag called [$tname] ($stag)");
continue;
}
// Tag found
$bbtag = $bbtags[$tname];
if ($bbtag['args'] > 0)
{
$tlen = strlen($tname) + 2;
// Handle associative tags
if ($bbtag['args'] > 3)
{
$i = $tstart + $tlen;
if (ctype_space($str[$i-1])) {
$args = read_attr_list($str, $i);
if ($args === NULL) { // Bail on failure
$i = FALSE;
return $outstr . parse_nonbb(substr($str, $bookmark));
}
++$i;
}
else if ($str[$i-1] == ']')
$args = array();
else continue;
}
else {
$args = NULL;
if ($bbtag['args'] == 1 && $str[$tstart + $tlen - 1] != ']') {
notice("$str [$tstart+$tlen-1] != ']'");
continue;
}
}
$arg0 = '';
for (;;) {
// This is where shit gets interesting
$arg0 .= parse_sub($str, $i);
// Make sure we arrived at our own closing tag
if ($i == FALSE)
return $outstr . parse_nonbb(substr($str, $bookmark));
$close = strpos($str, ']', $i);
$ctag = substr($str, $i, $close - $i);
if (strncasecmp($ctag, '[/'.$tname, $tlen) != 0) {
notice("strncasecmp('$ctag', '[/'.'$tname', '$tlen') != 0");
$arg0 .= $str[$i++];
continue; // If not, just keep looking
}
break;
}
// Now we have a little more parsing to do for ternary tags
if ($bbtag['args'] == 3) {
$arg2 = trim(substr($str, $i + $tlen, $close - $i - $tlen));
if (strlen($arg2) > 0 && $arg2[0] == '=')
$arg2 = trim(substr($arg2, 1));
}
else
$arg2 = NULL;
$i = $close + 1;
}
else
$arg0 = $arg1 = $arg2 = $args = NULL;
$outstr .= parse_nonbb(substr($str, $bookmark, $tstart - $bookmark));
$outstr .= evaluate_tag($tname, $bbtag, $arg0, $arg1, $arg2, $args);
$bookmark = $i;
}
$outstr .= substr($str, $bookmark);
return $outstr;
}
/*! This function might as well be in that last block of code,
* but it was getting frighteningly big, so I moved it here.
* @note Unused tag arguments should be NULL; \p $arg1 and \p $arg2 should
* never be non-null at the same time as \p $args.
* @param $tname The name of the tag.
* @param $bbtag The tag array from the \c bbtags array.
* @param $arg0 The first argument, the text between the tags, if applicable.
* @param $arg1 The second argument, the = value in the opening tag, if applicable.
* @param $arg2 The third argument, the = value in the closing tag, if applicable.
* @param $args An associative array of arguments, if applicable.
* @return Returns the result of evaluating the tag;
* a string with which to replace the tag.
*/
function evaluate_tag($tname, $bbtag, $arg0, $arg1, $arg2, $args) {
switch ($bbtag['type'])
{
case TT_TRIVIAL: switch ($bbtag['args']) {
case 0: return "<$tname />";
case 1: return "<$tname>$arg0</$tname>";
case 2: return "<!-- This tag is invalid -->";
case 3: return "<!-- This tag is invalid -->";
default: return "<!-- This tag would be a security risk -->";
}
case TT_INTERLEAVE: $h = $bbtag['html']; switch ($bbtag['args']) {
case 0: return $h[0];
case 1: return $h[0] . $arg0 . $h[1];
case 2: return $h[0] . $arg1 . $h[1] . $arg0 . $h[2];
case 3: return $h[0] . $arg1 . $h[1] . $arg0 . $h[2] . $arg2 . $h[3];
default: return "<!-- This tag cannot be automated -->";
}
case TT_CALLBACK: $f = $bbtag['func']; switch ($bbtag['args']) {
case 0: return $f();
case 1: return $f($arg0);
case 2: return $f($arg0, $arg1);
case 3: return $f($arg0, $arg1, $arg2);
default: return $f($arg0, $args);
}
}
}
/*! This nonsense is to parse associative tags.
* @param $str The string from which to read attributes.
* @param $i [in/out] The position from which to start reading.
* Set at end of function call to denote the end of the list.
* @return Returns the associative array read in from the string.
*/
function read_attr_list($str, &$i) {
$len = strlen($str);
$attrs = array();
while ($i < $len && $str[$i] != ']')
{
if (ctype_space($str[$i]))
continue;
// Read an attribute name
$attr_start = $i;
while (++$i < $len && $str[$i] != '='
&& !ctype_space($str[$i-1]));
$attr_name = substr($str, $attr_start, $i-$attr_start);
// Read past the attribute name
while ($i < $len && ctype_space($str[$i]))
++$i;
if ($i >= $len) // Bail if out of bounds
{ notice("OOB1"); return NULL; }
if ($str[$i] == '=')
{
while (++$i < $len && ctype_space($str[$i]));
if ($str[$i] == '"' || $str[$i] == '\'')
{
$val_start = $i + 1;
$ochar = $str[$i];
while (++$i < $len && $str[$i] != $ochar)
if ($str[$i] == '\\') ++$i;
if ($i >= $len)
{ notice("OOB2"); return NULL; }
$val = str_replace(
array("\\\\", "\\\'", "\\\"", "\\r", "\\n", "\\t"),
array("\\", "\'", "\"", "\r", "\n", "\t"),
substr($str, $val_start, $i - $val_start)
);
}
else {
$val_start = $i;
while (++$i < $len && $str[$i] != ']' && !ctype_space($str[$i]));
if ($i >= $len)
{ notice("OOB3"); return NULL; }
$val = substr($str, $val_start, $i - $val_start);
}
}
else $val = NULL;
$attrs[$attr_name] = $val;
}
return $attrs;
}
/*!
* Parse for non-BBCode elements, such as URLs or (God forbid) Markdown.
* @param $str HTML-escaped plain text input.
* @return Returns HTML-formatted parsed text.
*/
function parse_nonbb($str)
{
// Note: this is a fantastic place to put a Markdown parser
// fuk u fsx
$urlexp = "/(?i)\b("
. "(?:https?:\/\/|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)"
. "(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+"
. "(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'\".,<>?«»“”‘’])"
.")/";
return preg_replace($urlexp, "<a href=\"$1\">$1</a>", $str);
}
/*! Main BBCode parser call.
* @param $str The BBCode string to parse.
* @return Returns the HTML parsed version of the input.
*/
function parse_bbcode($str) {
$i = 0;
$res = "";
while ($i !== false) {
$res .= parse_sub($str, $i);
if ($i !== false)
$res .= $str[$i++];
}
return $res;
}
echo "Result:<br/>\n";
echo parse_bbcode(
"This is some [b]cool shit[/b], I'm sure you'll agree.
Italics: [i]check[/i].
Bold italics: [b][i]check[/i] and [i]double check[/i][/b]
Now, let's try [url=asses]some urls[/url].
And now, let's try [url = asses in thongs]urls with gaps[/url].
For good measure, [grad=red]graded spans[/grad=blue].
To fuck shit up, [grad=red]graded spans[/grad].
To really fuck shit up, [grad]graded spans[/grad].
Okay, [bubble]complicated tag time[/bubble]!
Now, [bubble radius='5' color=255]more complicated tag time[/bubble]!
Finally, [bubble radius='5[b]ha[/b][/bubble]' color=255]extremely complicated tag time[/bubble]!
This is an unmatched closing italic tag: [/i]
Here's one in a bold tag: [b]wat[/[/i][/[[/b]
[b]This is a matched bold tag.[/b]
This concludes the BBCode portion of your exam.
URLs:
www.google.com
http://google.com
[b]Thank you for flying air BB[/b]
Goodbye.
");
?>
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