using PCLZIP_CB_PRE_EXTRACT of Pclzip.php in a class

<?php // for highlighting
$extract = $zip->extract(PCLZIP_OPT_PATH, '../'.$gdir,
                         PCLZIP_CB_PRE_EXTRACT, 'zipPreExtractCallBack');
if ( $extract == 0 ) {
    $_SESSION['easy2err'][] = "Error : ".$zip->errorInfo(TRUE);
} else {
    $_SESSION['easy2suc'][] = $j.' '.$lng['files_uploaded'].'.';
}

<?php 
/*
 * PclZip PCLZIP_CB_PRE_EXTRACT to convert filenames while extracting the content.
*/
function zipPreExtractCallBack($p_event, &$p_header) {
    $info = pathinfo($p_header['filename']);
    $p_header['filename'] = iconv("ISO-8859-1", "UTF-8", $p_header['filename']);
    return 1;
}

<?php
// not working
header('Content-Type: text/html; charset=UTF-8');
iconv_set_encoding("internal_encoding", "UTF-8");
iconv_set_encoding("input_encoding", "UTF-8");
iconv_set_encoding("output_encoding", "UTF-8");

<?php
class e2g_mod {

private function _explore() {
/*
 * PclZip PCLZIP_CB_PRE_EXTRACT to convert filenames while extracting the content.
*/
if (!function_exists('zipPreExtractCallBack')) {
    function zipPreExtractCallBack($p_event, &$p_header) {
        $info = pathinfo($p_header['filename']);
        // limit the unzipped images
        if ($info['extension'] == 'jpeg' || $info['extension'] == 'jpg' || $info['extension'] == 'gif' || $info['extension'] == 'png') {
            if ( iconv_get_encoding("input_encoding") != "UTF-8" ) {
                iconv_set_encoding("input_encoding", "UTF-8");
            }
            // below is another option
            //$p_header['filename'] = iconv("Latin1", "ISO-8859-1", $p_header['filename'] );
            //die('125 '.var_dump(iconv_get_encoding('all')));
            return 1;
        }
        // other file extension will not be unzipped
        else return 0;
    }
}
$extract = $zip->extract(PCLZIP_OPT_PATH, '../'.$gdir
                         , PCLZIP_CB_PRE_EXTRACT, 'zipPreExtractCallBack'
                        );

// more codes....
    }
}

<?php
if (!function_exists('zipPreExtractCallBack')) {
    function zipPreExtractCallBack($p_event, &$p_header) {
        $info = pathinfo($p_header['filename']);
        // limit the unzipped images
        if ($info['extension'] == 'jpeg' || $info['extension'] == 'jpg' || $info['extension'] == 'gif' || $info['extension'] == 'png') {
            $get_host_iconv_encode = iconv_get_encoding("internal_encoding");
            $get_file_mb_encode = mb_detect_encoding( $info['basename'] );
            $p_header['filename'] = iconv( $get_host_iconv_encode , $get_file_mb_encode.'//TRANSLIT//IGNORE' , $p_header['filename'] );
            return 1;
        }
        // other file extension will not be unzipped
        else return 0;
    }
}