<?php
/*
  Copyright 2007 Redshift Software, Inc.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
*/

/**
 * Return a callback to comparing the given field.
 * @return callable
 */

function sort_by_field($field)
{
    return '_field_cmp_'.strtolower(str_replace('-','_',$field)).'_';
}

function _field_cmp_($r,$a,$b)
{
    if ($r == 0) { return _field_cmp_name_($a,$b); }
    else { return $r; }
}

function _field_cmp_authors_($a,$b)
{ return _field_cmp_(strcmp($a['authors'],$b['authors']),$a,$b); }

function _field_cmp_boost_version_($a,$b)
{
    return BoostVersion::from($a['boost-version'])
        ->compare($b['boost-version']);
}

function _field_cmp_description_($a,$b)
{ return strcmp($a['description'],$b['description']); }

function _field_cmp_documentation_($a,$b)
{ return strcmp($a['documentation'],$b['documentation']); }

function _field_cmp_guid_($a,$b)
{ return strcmp($a['guid'],$b['guid']); }

function _field_cmp_key_($a,$b)
{ return strcmp($a['key'],$b['key']); }

function _field_cmp_less_($i,$j)
{
    return ($i == $j) ? 0 : ($i !== FALSE && ($j === FALSE || $i < $j) ? -1 : 1);
}

function _field_cmp_name_($a,$b)
{ return strcasecmp($a['name'],$b['name']); }

function _field_cmp_pubdate_($a,$b)
{ return _field_cmp_less_($b['pubdate'],$a['pubdate']); }

function _field_cmp_std_proposal_($a,$b)
{ return _field_cmp_(_field_cmp_less_($a['std-proposal'],$b['std-proposal']),$a,$b); }

function _field_cmp_std_tr1_($a,$b)
{ return _field_cmp_(_field_cmp_less_($a['std-tr1'],$b['std-tr1']),$a,$b); }

function _field_cmp_title_($a,$b)
{ return strcmp($a['title'],$b['title']); }

?>