Characters being replaced by bbcode plugin - php

Question

I have a bbcode plugin for wordpress.
But for some reason, if I post something like
[i]v497212he2x2MfMi[/i] the "X" character is outputted as ×, which is some other sort of X. How can I fix this?
Plugin code is below:
class BBCode {
// Plugin initialization
function BBCode() {
// This version only supports WP 2.5+ (learn to upgrade please!)
if ( !function_exists('add_shortcode') ) return;
// Register the shortcodes
add_shortcode( 'b' , array(&$this, 'shortcode_bold') );
add_shortcode( 'i' , array(&$this, 'shortcode_italics') );
}
// No-name attribute fixing
function attributefix( $atts = array() ) {
if ( empty($atts[0]) ) return $atts;
if ( 0 !== preg_match( '#=("|\')(.*?)("|\')#', $atts[0], $match ) )
$atts[0] = $match[2];
return $atts;
}
// Bold shortcode
function shortcode_bold( $atts = array(), $content = NULL ) {
if ( NULL === $content ) return '';
return '<strong>' . do_shortcode( $content ) . '</strong>';
}
// Italics shortcode
function shortcode_italics( $atts = array(), $content = NULL ) {
if ( NULL === $content ) return '';
return '<em>' . do_shortcode( $content ) . '</em>';
}
}
// Start this plugin once all other plugins are fully loaded
add_action( 'plugins_loaded', create_function( '', 'global $BBCode; $BBCode = new BBCode();' ) );

Answer 1

This transformation is taking place because of Wordpress's wptexturize() function that returns given text with transformations of quotes to smart quotes, apostrophes, dashes, ellipses, the trademark symbol, and the multiplication symbol.
This is from WP 3.2.1 wp-includes/formatting.php line 55:
$dynamic_characters = array('/\'(\d\d(?:’|\')?s)/', '/\'(\d)/', '/(\s|\A|[([{<]|")\'/', '/(\d)"/', '/(\d)\'/', '/(\S)\'([^\'\s])/', '/(\s|\A|[([{<])"(?!\s)/', '/"(\s|\S|\Z)/', '/\'([\s.]|\Z)/', '/\b(\d+)x(\d+)\b/');
$dynamic_replacements = array('’$1','’$1', '$1‘', '$1″', '$1′', '$1’$2', '$1' . $opening_quote . '$2', $closing_quote . '$1', '’$1', '$1×$2');
The last regex in that $dynamic_characters array is the one turning the "X" into ×
As stated on the function page for wptexturize... "[t]ext enclosed in the tags <pre>, <code>, <kbd>, <style>, <script>, <tt>, and [code] will be skipped.", you can fix this by putting that bbcode in one of those tags, or use a plugin that can disable wptexturize, such as InScript or Disabler or Disable wptexturize.