Custom page next previous code drupal module for node pages

PHP code or module code goes as below:
<?php
/**
 *@desc provides previous node object for caller
 * @param <type> $node
 * @param <type> $same_type
 * @return <type>
 */
function _prev_node_link($node=NULL,$same_type=FALSE){
    if(
$same_type){
       
$old_node=db_fetch_object(db_query_range("SELECT * from {node} WHERE nid<'%d' AND status=1 AND type='%s' ORDER BY nid DESC",$node->nid,$node->type,0,1));

    }else{
       
$old_node=db_fetch_object(db_query_range("SELECT * from {node} WHERE nid<'%d' AND status=1 ORDER BY nid DESC",$node->nid,0,1));
    }
    return
$old_node;
}
?>
<?php
//Custom pager Links for nodes goes here
/**
 *@desc Return next closest node object data caller
 * @param <type> $node
 * @param <type> $same_type
 * @return <type>
 */
function _next_node_link($node=NULL,$same_type=FALSE){
    if(
$same_type){
       
$old_node=db_fetch_object(db_query_range("SELECT * from {node} WHERE nid>'%d' AND status=1 AND type='%s' ORDER BY nid ASC",$node->nid,$node->type,0,1));

    }else{
       
$old_node=db_fetch_object(db_query_range("SELECT * from {node} WHERE nid>'%d' AND status=1 ORDER BY nid ASC",$node->nid,0,1));
    }
    return
$old_node;
}
?>
<?php
/**
 *
 */
function inders_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL){
    if(
$op=="load"){
      
$node->pager_info['prev']=_prev_node_link($node,TRUE);
      
$node->pager_info['next']=_next_node_link($node,TRUE);
    }elseif(
$op=="view"){
    }
}
/**
 *
 * @param <type> $vars
 */
function inders_preprocess_node(&$vars){
   if(isset(
$vars['pager_info']['prev']))
           
$vars['inders_pager_info']['prev']=l("<<".$vars['pager_info']['prev']->title,"node/".$vars['pager_info']['prev']->nid);
   if(isset(
$vars['pager_info']['next']))
           
$vars['inders_pager_info']['next']=l($vars['pager_info']['next']->title." >>","node/".$vars['pager_info']['next']->nid);
}
/**
 *
 */
?>
And you can use dummy css from here:
.inders-pager{
    clear:both;
    float:none;
    height:26px;
    padding-bottom:5px;
    padding-top:5px;
}
.inders-pager-prev{
    float:left;
    margin-right: 5px;
}
.inders-pager-next{
    float:right;
    margin-left: 5px;
    color: white;
}
.inders-pager-prev a{
    color: white;
    background-color:#8F9CBF;
    padding:3px;
}
.inders-pager-next a{
    color: white;
    background-color:#4F9F5A;
    padding:3px;
}
.clear{
        clear:both;
}