root/branches/1.5/wp-includes/template-functions-category.php

<?php

function get_the_category($id = false) {
    global $post, $category_cache;

    if ( !$id )
        $id = $post->ID;

    if ( ! isset($category_cache[$id]) )
        update_post_category_cache($id);

    $categories = $category_cache[$id];

    if (!empty($categories))
        sort($categories);
    else
        $categories = array();

    return $categories;
}

function get_category_link($category_id) {
    global $wp_rewrite;
    $catlink = $wp_rewrite->get_category_permastruct();

    if ( empty($catlink) ) {
        $file = get_settings('home') . '/' . get_settings('blogfilename');
        $catlink = $file . '?cat=' . $category_id;
    } else {
        $category = &get_category($category_id);
        $category_nicename = $category->category_nicename;

        if ($parent = $category->category_parent) 
            $category_nicename = get_category_parents($parent, false, '/', true) . $category_nicename . '/';

        $catlink = str_replace('%category%', $category_nicename, $catlink);
        $catlink = get_settings('home') . trailingslashit($catlink);
    }
    return apply_filters('category_link', $catlink, $category_id);
}

function get_the_category_list($separator = '', $parents='') {
    $categories = get_the_category();
    if (empty($categories)) {
            return apply_filters('the_category', __('Uncategorized'), $separator, $parents);
    }

    $thelist = '';
    if ('' == $separator) {
        $thelist .= '<ul class="post-categories">';
        foreach ($categories as $category) {
            $category->cat_name = $category->cat_name;
            $thelist .= "\n\t<li>";
            switch(strtolower($parents)) {
                case 'multiple':
                    if ($category->category_parent) {
                        $thelist .= get_category_parents($category->category_parent, TRUE);
                    }
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . '" rel="category tag">'.$category->cat_name.'</a></li>';
                    break;
                case 'single':
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . ' rel="category tag">';
                    if ($category->category_parent) {
                        $thelist .= get_category_parents($category->category_parent, FALSE);
                    }
                    $thelist .= $category->cat_name.'</a></li>';
                    break;
                case '':
                default:
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . '" rel="category tag">'.$category->cat_name.'</a></li>';
            }
        }
        $thelist .= '</ul>';
    } else {
        $i = 0;
        foreach ($categories as $category) {
            $category->cat_name = $category->cat_name;
            if (0 < $i) $thelist .= $separator . ' ';
            switch(strtolower($parents)) {
                case 'multiple':
                    if ($category->category_parent)    $thelist .= get_category_parents($category->category_parent, TRUE);
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . '" rel="category tag">'.$category->cat_name.'</a>';
                    break;
                case 'single':
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . '" rel="category tag">';
                    if ($category->category_parent)    $thelist .= get_category_parents($category->category_parent, FALSE);
                    $thelist .= "$category->cat_name</a>";
                    break;
                case '':
                default:
                    $thelist .= '<a href="' . get_category_link($category->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $category->cat_name) . '" rel="category tag">'.$category->cat_name.'</a>';
            }
            ++$i;
        }
    }
    return apply_filters('the_category', $thelist, $separator, $parents);
}

function the_category($separator = '', $parents='') {
    echo get_the_category_list($separator, $parents);
}

function get_the_category_by_ID($cat_ID) {
    $cat_ID = (int) $cat_ID;
    $category = &get_category($cat_ID);
    return $category->cat_name;
}

function get_category_parents($id, $link = FALSE, $separator = '/', $nicename = FALSE){
    $chain = '';
        $parent = &get_category($id);
    if ($nicename) {
        $name = $parent->category_nicename;
    } else {
        $name = $parent->cat_name;
    }
    if ($parent->category_parent) $chain .= get_category_parents($parent->category_parent, $link, $separator, $nicename);
    if ($link) {
        $chain .= '<a href="' . get_category_link($parent->cat_ID) . '" title="' . sprintf(__("View all posts in %s"), $parent->cat_name) . '">'.$name.'</a>' . $separator;
    } else {
        $chain .= $name.$separator;
    }
    return $chain;
}

function get_category_children($id, $before = '/', $after = '') {
    global $cache_categories;

    if ( ! isset($cache_categories))
        update_category_cache();
        
    $c_cache = $cache_categories; // Can't do recursive foreach on a global, have to make a copy
    $chain = '';
    foreach ($c_cache as $category){
        if ($category->category_parent == $id){
            $chain .= $before.$category->cat_ID.$after;
            $chain .= get_category_children($category->cat_ID, $before, $after);
        }
    }
    return $chain;
}

// Deprecated.
function the_category_ID($echo = true) {
    // Grab the first cat in the list.
    $categories = get_the_category();
    $cat = $categories[0]->cat_ID;
    
    if ($echo) echo $cat;

    return $cat;
}

// Deprecated.
function the_category_head($before='', $after='') {
    global $currentcat, $previouscat;
    // Grab the first cat in the list.
    $categories = get_the_category();
    $currentcat = $categories[0]->category_id;
    if ($currentcat != $previouscat) {
        echo $before;
        echo get_the_category_by_ID($currentcat);
        echo $after;
        $previouscat = $currentcat;
    }
}

function category_description($category = 0) {
    global $cat;
    if (!$category) $category = $cat;
        $category = & get_category($category);
    return apply_filters('category_description', $category->category_description, $category->cat_ID);
}

// out of the WordPress loop
function dropdown_cats($optionall = 1, $all = 'All', $sort_column = 'ID', $sort_order = 'asc',
        $optiondates = 0, $optioncount = 0, $hide_empty = 1, $optionnone=FALSE,
        $selected=0, $hide=0) {
    global $wpdb;
    if (($file == 'blah') || ($file == '')) $file = get_settings('home') . '/';
    if (!$selected) $selected=$cat;
    $sort_column = 'cat_'.$sort_column;

    $query = "
        SELECT cat_ID, cat_name, category_nicename,category_parent,
        COUNT($wpdb->post2cat.post_id) AS cat_count,
        DAYOFMONTH(MAX(post_date)) AS lastday, MONTH(MAX(post_date)) AS lastmonth
        FROM $wpdb->categories LEFT JOIN $wpdb->post2cat ON (cat_ID = category_id)
        LEFT JOIN $wpdb->posts ON (ID = post_id)
        WHERE cat_ID > 0
        ";
    if ($hide) {
        $query .= " AND cat_ID != $hide";
        $query .= get_category_children($hide, " AND cat_ID != ");
    }
    $query .=" GROUP BY cat_ID";
    if (intval($hide_empty) == 1) $query .= " HAVING cat_count > 0";
    $query .= " ORDER BY $sort_column $sort_order, post_date DESC";

    $categories = $wpdb->get_results($query);
    echo "<select name='cat' class='postform'>\n";
    if (intval($optionall) == 1) {
        $all = apply_filters('list_cats', $all);
        echo "\t<option value='0'>$all</option>\n";
    }
    if (intval($optionnone) == 1) echo "\t<option value='-1'>".__('None')."</option>\n";
    if ($categories) {
        foreach ($categories as $category) {
            $cat_name = apply_filters('list_cats', $category->cat_name, $category);
            echo "\t<option value=\"".$category->cat_ID."\"";
            if ($category->cat_ID == $selected)
                echo ' selected="selected"';
            echo '>';
            echo $cat_name;
            if (intval($optioncount) == 1) echo '&nbsp;&nbsp;('.$category->cat_count.')';
            if (intval($optiondates) == 1) echo '&nbsp;&nbsp;'.$category->lastday.'/'.$category->lastmonth;
            echo "</option>\n";
        }
    }
    echo "</select>\n";
}

// out of the WordPress loop
function wp_list_cats($args = '') {
    parse_str($args, $r);
    if (!isset($r['optionall'])) $r['optionall'] = 0;
    if (!isset($r['all'])) $r['all'] = 'All';
    if (!isset($r['sort_column'])) $r['sort_column'] = 'ID';
    if (!isset($r['sort_order'])) $r['sort_order'] = 'asc';
    if (!isset($r['file'])) $r['file'] = '';
    if (!isset($r['list'])) $r['list'] = true;
    if (!isset($r['optiondates'])) $r['optiondates'] = 0;
    if (!isset($r['optioncount'])) $r['optioncount'] = 0;
    if (!isset($r['hide_empty'])) $r['hide_empty'] = 1;
    if (!isset($r['use_desc_for_title'])) $r['use_desc_for_title'] = 1;
    if (!isset($r['children'])) $r['children'] = true;
    if (!isset($r['child_of'])) $r['child_of'] = 0;
    if (!isset($r['categories'])) $r['categories'] = 0;
    if (!isset($r['recurse'])) $r['recurse'] = 0;
    if (!isset($r['feed'])) $r['feed'] = '';
    if (!isset($r['feed_image'])) $r['feed_image'] = '';
    if (!isset($r['exclude'])) $r['exclude'] = '';
    if (!isset($r['hierarchical'])) $r['hierarchical'] = true;

    list_cats($r['optionall'], $r['all'], $r['sort_column'], $r['sort_order'], $r['file'],    $r['list'], $r['optiondates'], $r['optioncount'], $r['hide_empty'], $r['use_desc_for_title'], $r['children'], $r['child_of'], $r['categories'], $r['recurse'], $r['feed'], $r['feed_image'], $r['exclude'], $r['hierarchical']);
}

function list_cats($optionall = 1, $all = 'All', $sort_column = 'ID', $sort_order = 'asc', $file = '', $list = true, $optiondates = 0, $optioncount = 0, $hide_empty = 1, $use_desc_for_title = 1, $children=FALSE, $child_of=0, $categories=0, $recurse=0, $feed = '', $feed_image = '', $exclude = '', $hierarchical=FALSE) {
    global $wpdb, $category_posts;
    // Optiondates now works
    if ('' == $file) {
        $file = get_settings('home') . '/';
    }

    $exclusions = '';
    if (!empty($exclude)) {
        $excats = preg_split('/[\s,]+/',$exclude);
        if (count($excats)) {
            foreach ($excats as $excat) {
                $exclusions .= ' AND cat_ID <> ' . intval($excat) . ' ';
            }
        }
    }

    $exclusions = apply_filters('list_cats_exclusions', $exclusions);

    if (intval($categories)==0){
        $sort_column = 'cat_'.$sort_column;

        $query  = "
            SELECT cat_ID, cat_name, category_nicename, category_description, category_parent
            FROM $wpdb->categories
            WHERE cat_ID > 0 $exclusions
            ORDER BY $sort_column $sort_order";

        $categories = $wpdb->get_results($query);
    }
    if (!count($category_posts)) {
        $now = current_time('mysql', 1);
        $cat_counts = $wpdb->get_results("    SELECT cat_ID,
        COUNT($wpdb->post2cat.post_id) AS cat_count
        FROM $wpdb->categories 
        INNER JOIN $wpdb->post2cat ON (cat_ID = category_id)
        INNER JOIN $wpdb->posts ON (ID = post_id)
        WHERE post_status = 'publish'
        AND post_date_gmt < '$now' $exclusions
        GROUP BY category_id");
        if (! empty($cat_counts)) {
            foreach ($cat_counts as $cat_count) {
                if (1 != intval($hide_empty) || $cat_count > 0) {
                    $category_posts["$cat_count->cat_ID"] = $cat_count->cat_count;
                }
            }
        }
    }
    
    if ( $optiondates ) {
        $cat_dates = $wpdb->get_results("    SELECT category_id,
        UNIX_TIMESTAMP( MAX(post_date) ) AS ts
        FROM $wpdb->posts, $wpdb->post2cat
        WHERE post_status = 'publish' AND post_id = ID $exclusions
        GROUP BY category_id");
        foreach ($cat_dates as $cat_date) {
            $category_timestamp["$cat_date->category_id"] = $cat_date->ts;
        }
    }
    
    $num_found=0;
    $thelist = "";
    
    foreach ($categories as $category) {
        if ((intval($hide_empty) == 0 || isset($category_posts["$category->cat_ID"])) && (!$hierarchical || $category->category_parent == $child_of) ) {
            $num_found++;
            $link = '<a href="'.get_category_link($category->cat_ID).'" ';
            if ($use_desc_for_title == 0 || empty($category->category_description)) {
                $link .= 'title="'. sprintf(__("View all posts filed under %s"), wp_specialchars($category->cat_name)) . '"';
            } else {
                $link .= 'title="' . wp_specialchars(apply_filters('category_description',$category->category_description,$category)) . '"';
            }
            $link .= '>';
            $link .= apply_filters('list_cats', $category->cat_name, $category).'</a>';

            if ( (! empty($feed_image)) || (! empty($feed)) ) {
                
                $link .= ' ';

                if (empty($feed_image)) {
                    $link .= '(';
                }

                $link .= '<a href="' . get_category_rss_link(0, $category->cat_ID, $category->category_nicename)  . '"';

                if ( !empty($feed) ) {
                    $title =  ' title="' . $feed . '"';
                    $alt = ' alt="' . $feed . '"';
                    $name = $feed;
                    $link .= $title;
                }

                $link .= '>';

                if (! empty($feed_image)) {
                    $link .= "<img src='$feed_image' $alt$title" . ' />';
                } else {
                    $link .= $name;
                }
                
                $link .= '</a>';

                if (empty($feed_image)) {
                    $link .= ')';
                }
            }

            if (intval($optioncount) == 1) {
                $link .= ' ('.intval($category_posts["$category->cat_ID"]).')';
            }
            if ( $optiondates ) {
                if ( $optiondates == 1 ) $optiondates = 'Y-m-d';
                $link .= ' ' . gmdate($optiondates, $category_timestamp["$category->cat_ID"]);
            }
            if ($list) {
                $thelist .= "\t<li>$link\n";
            } else {
                $thelist .= "\t$link<br />\n";
            }
            if ($hierarchical && $children) $thelist .= list_cats($optionall, $all, $sort_column, $sort_order, $file, $list, $optiondates, $optioncount, $hide_empty, $use_desc_for_title, $hierarchical, $category->cat_ID, $categories, 1, $feed, $feed_image, $exclude, $hierarchical);
            if ($list) $thelist .= "</li>\n";
            }
    }
    if (!$num_found && !$child_of){
        if ($list) {
            $before = '<li>';
            $after = '</li>';
        }
        echo $before . __("No categories") . $after . "\n";
        return;
    }
    if ($list && $child_of && $num_found && $recurse) {
        $pre = "\t\t<ul class='children'>";
        $post = "\t\t</ul>\n";
    } else {
        $pre = $post = '';
    }
    $thelist = $pre . $thelist . $post;
    if ($recurse) {
        return $thelist;
    }
    echo apply_filters('list_cats', $thelist);
}

function in_category($category) { // Check if the current post is in the given category
    global $post, $category_cache;
    $cats = '';
    foreach ($category_cache[$post->ID] as $cat) :
        $cats[] = $cat->cat_ID;
    endforeach;

    if ( in_array($category, $cats) )
        return true;
    else
        return false;
}
?>