WordPress/wp-admin/categories.php

<?php
$title = 'Categories';
/* <Categories> */

function add_magic_quotes($array) {
	foreach ($array as $k => $v) {
		if (is_array($v)) {
			$array[$k] = add_magic_quotes($v);
		} else {
			$array[$k] = addslashes($v);
		}
	}
	return $array;
} 

if (!get_magic_quotes_gpc()) {
	$HTTP_GET_VARS    = add_magic_quotes($HTTP_GET_VARS);
	$HTTP_POST_VARS   = add_magic_quotes($HTTP_POST_VARS);
	$HTTP_COOKIE_VARS = add_magic_quotes($HTTP_COOKIE_VARS);
}

$wpvarstoreset = array('action','standalone','cat');
for ($i=0; $i<count($wpvarstoreset); $i += 1) {
	$wpvar = $wpvarstoreset[$i];
	if (!isset($$wpvar)) {
		if (empty($HTTP_POST_VARS["$wpvar"])) {
			if (empty($HTTP_GET_VARS["$wpvar"])) {
				$$wpvar = '';
			} else {
				$$wpvar = $HTTP_GET_VARS["$wpvar"];
			}
		} else {
			$$wpvar = $HTTP_POST_VARS["$wpvar"];
		}
	}
}

switch($action) {

case 'addcat':

	$standalone = 1;
	require_once('admin-header.php');
	
	if ($user_level < 3)
		die ('Cheatin&#8217; uh?');
	
	$cat_name= addslashes(stripslashes(stripslashes($HTTP_POST_VARS['cat_name'])));
	$category_nicename = sanitize_title($cat_name);
	$category_description = addslashes(stripslashes(stripslashes($HTTP_POST_VARS['category_description'])));
	
	$wpdb->query("INSERT INTO $tablecategories (cat_ID, cat_name, category_nicename, category_description) VALUES ('0', '$cat_name', '$category_nicename', '$category_description')");
	
	header('Location: categories.php');

break;

case 'Delete':

	$standalone = 1;
	require_once('admin-header.php');

	$cat_ID = intval($HTTP_GET_VARS["cat_ID"]);
	$cat_name = get_catname($cat_ID);
	$cat_name = addslashes($cat_name);

	if (1 == $cat_ID)
		die("Can't delete the <strong>$cat_name</strong> category: this is the default one");

	if ($user_level < 3)
		die ('Cheatin&#8217; uh?');

	$wpdb->query("DELETE FROM $tablecategories WHERE cat_ID = $cat_ID");
	$wpdb->query("UPDATE $tablepost2cat SET category_id='1' WHERE category_id='$cat_ID'");

	header('Location: categories.php');

break;

case 'edit':

	require_once ('admin-header.php');
	$category = $wpdb->get_row("SELECT * FROM $tablecategories WHERE cat_ID = " . $HTTP_GET_VARS['cat_ID']);
	$cat_name = stripslashes($category->cat_name);
	?>

<div class="wrap">
	<h2>Edit Category</h2>
	<form name="editcat" action="categories.php" method="post">
		<input type="hidden" name="action" value="editedcat" />
		<input type="hidden" name="cat_ID" value="<?php echo $HTTP_GET_VARS['cat_ID'] ?>" />
		<p>Category name:<br />
		<input type="text" name="cat_name" value="<?php echo $cat_name; ?>" /></p>
		<p>Description:<br />
		<textarea name="category_description" rows="5" cols="50" style="width: 97%;"><?php echo htmlentities($category->category_description); ?></textarea></p>
		<p><input type="submit" name="submit" value="Edit it!" class="search" /></p>
	</form>
</div>

	<?php

break;

case 'editedcat':

	$standalone = 1;
	require_once('admin-header.php');

	if ($user_level < 3)
		die ('Cheatin&#8217; uh?');
	
	$cat_name = addslashes(stripslashes(stripslashes($HTTP_POST_VARS['cat_name'])));
	$cat_ID = addslashes($HTTP_POST_VARS['cat_ID']);
	$category_nicename = sanitize_title($cat_name);
	$category_description = $HTTP_POST_VARS['category_description'];

	$wpdb->query("UPDATE $tablecategories SET cat_name = '$cat_name', category_nicename = '$category_nicename', category_description = '$category_description' WHERE cat_ID = $cat_ID");
	
	header('Location: categories.php');

break;

default:

	$standalone = 0;
	require_once ('admin-header.php');
	if ($user_level < 3) {
		die("You have no right to edit the categories for this blog.<br />Ask for a promotion to your <a href='mailto:$admin_email'>blog admin</a>. :)");
	}
	?>

<div class="wrap">
	<h2>Current Categories</h2>
	<table width="100%" cellpadding="3" cellspacing="3">
	<tr>
		<th scope="col">Name</th>
		<th scope="col">Description</th>
		<th scope="col"># Posts</th>
		<th colspan="2">Action</th>
	</tr>
	<?php
	$categories = $wpdb->get_results("SELECT * FROM $tablecategories ORDER BY cat_name");
	foreach ($categories as $category) {
		$count = $wpdb->get_var("SELECT COUNT(post_id) FROM $tablepost2cat WHERE category_id = $category->cat_ID");
		$bgcolor = ('#eee' == $bgcolor) ? 'none' : '#eee';
		echo "<tr style='background-color: $bgcolor'><td>$category->cat_name</td>
		<td>$category->category_description</td>
		<td>$count</td>
		<td><a href='categories.php?action=edit&amp;cat_ID=$category->cat_ID' class='edit'>Edit</a></td><td><a href='categories.php?action=Delete&amp;cat_ID=$category->cat_ID' onclick=\"return confirm('You are about to delete the category \'". addslashes($category->cat_name) ."\' and all its posts will go to the default category.\\n  \'OK\' to delete, \'Cancel\' to stop.')\" class='delete'>Delete</a></td>
		</tr>";
	}
	?>
	</table>

</div>
<div class="wrap">
	<h2>Add New Category</h2>
	<form name="addcat" action="categories.php" method="post">
		
		<p>Name:<br />
		<input type="text" name="cat_name" value="" /></p>
		<p>Description: (optional) <br />
		<textarea name="category_description" rows="5" cols="50" style="width: 97%;"></textarea></p>
		<p><input type="hidden" name="action" value="addcat" /><input type="submit" name="submit" value="Add" class="search" /></p>
	</form>
</div>


<div class="wrap"> 
  <p><strong>Note:</strong><br />
    Deleting a category does not delete posts from that category, it will just 
    set them back to the default category <strong><?php echo get_catname(1) ?></strong>. 
  </p>
</div>

	<?php
break;
}

/* </Categories> */
include('admin-footer.php');
?>