File: StoryPager.lib

<?php

/* ====================================================================
 * Copyright (c) 2000 Steven Haryanto.  All rights reserved.
 *
 * StoryPager
 *   A PHP module to do automatic story paging
 * 
 * This module is released under the GNU General Public License. See:
 *   http://www.gnu.org/copyleft/gpl.html
 * 
 * Version
 *   0.011, Wed Dec 13 03:24:45 2000 
 *
 * For latest version and example, visit:
 *   http://steven.haryan.to/php/StoryPager.html
 * 
 * ====================================================================
 *
 */

class StoryPager {

    function StoryPager() {
        // default values
        $this->nb_tag = "<!-- NOBREAK -->";
        $this->mb_tag = "<!-- BREAK -->";
        $this->even_paging = 1;
    }

    // whether to do even paging
    function even_paging($value) {
        if (isset($value)) $this->even_paging = $value;
        return $this->even_paging;
    }

    // target number of pages
    function target_nop($value) {
        if (isset($value)) $this->target_nop = $value;
        return $this->target_nop;
    }

    // optimum page length, in bytes
    function optimum_pl($value) {
        if (isset($value)) $this->optimum_pl = $value;
        return $this->optimum_pl;
    }

    // string to look for to prevent breaking/paging the whole story
    function nb_tag($value) {
        if (isset($value)) $this->nb_tag = $value;
        return $this->nb_tag;
    }

    // string to look for doing manual breaking
    function mb_tag($value) {
        if (isset($value)) $this->mb_tag = $value;
        return $this->mb_tag;
    }

    // do the split
    function split($content) {
        $this->pages = array();

        // should we break at all?
        if (preg_match("/\Q$this->nb_tag/is", &$content)) {
            push($this->pages, &$content);
            return;
        }

        // if yes, should we manual-break?
        if (preg_match("/\Q$this->mb_tag/is", &$content)) {
            $this->pages = preg_split("/\Q$this->mb_tag/is", &$content);
            return;
        }

        // if no manual break is specified, try to do automatic paging
        $content_length = strlen(&$content);

        if (!$this->even_paging) {
            if (!$this->optimum_pl) {
                die("You must specify desired page length (optimum_pl)");
            }
            if ($this->target_nop) {
                $pl = round(strlen(&$content)/$this->target_nop);
            } else {
                $pl = $this->optimum_pl;
            }
        } else {

            if ($this->target_nop) {
                $nop = $this->target_nop;
            } else if ($this->optimum_pl) {
                $nop = round($content_length/$this->optimum_pl);
            } else {
                die("At least specify target number of pages (target_nop) ".
                    "or optimum page length (optimum_pl)");
            }
            if ($nop == 0) $nop=1;
            $pl = round($content_length/$nop);

        }

        $lines = explode("\n", &$content);
        $in_table = 0;
        $in_pre = 0;
        $offset = 0;
        $cur_offset = 0;
        $distance = 0;
        $index = 0;
        $this->pages[$index] = '';

        foreach ($lines as $line) {
            $linebr = $line . "\n";
            $len = strlen(&$linebr);

            $p_tag=0;

            $p_tag = preg_match("/<\/?p>/i", &$line);
            preg_match_all("/<pre>/i", &$line, $m); $in_pre += sizeof($m[0]);
            preg_match_all("/<table/i", &$line, $m); $in_table += sizeof($m[0]);
            $offset += $len;

            // is it time to start a new page?
            if (
                $in_pre <= 0 && $in_table <= 0 && 
                ($p_tag || !preg_match("/\S/", $line)) && 
                (!$this->target_nop || $index+1 < $this->target_nop) &&
                ($cur_offset > 0.75*$pl) && // don't let a page be too short
                $offset > $pl*($index+1) 
               ) {
                ++$index;
                $this->pages[$index] = $linebr;
                $cur_offset = 0;

            } else { // nope, keep writing to the current page

                $this->pages[$index] .= $linebr;
                $cur_offset += $len;

            }

            preg_match_all("/<\/pre>/i", &$line, $m); $in_pre -= sizeof($m[0]);
            preg_match_all("/<\/table>/i", &$line, $m); $in_table -= sizeof($m[0]);

        }

        // remove last page if empty
        // if (!preg_match("/\S/", $this->pages[$index])) array_pop($this->pages);
    }

    // retrieve the number of pages
    function nop() {
        return sizeof($this->pages);
    }

    // retrieve the pages
    function &page($index) {
        return $this->pages[$index-1];
    }

} // class

?>