PHP - CSV to map plus

csv-to-map_plus.php

<?php
if($_SERVER['SERVER_NAME'] === 'xxxxx.xxx' &&
   (!isset($_SERVER['HTTP_X_REQUESTED_WITH']) ||
    $_SERVER['HTTP_X_REQUESTED_WITH'] !== 'XMLHttpRequest')) {
  die(json_encode(array('status' => "Invalid call.")));
}
setlocale(LC_ALL, 'ja_JP.UTF-8');
function csv_to_map($csv) {
  $csv  = ereg_replace("\r\n|\r|\n", "\n", $csv);
  $csv  = mb_convert_encoding($csv, 'UTF-8', 'sjis-win');
  $temp = tmpfile();
  $meta = stream_get_meta_data($temp);
  fwrite($temp, $csv);
  rewind($temp);
  $file = new SplFileObject($meta['uri']);
  $file -> setFlags(SplFileObject::READ_CSV);
  $map  = array();
  $keys = array();
  foreach($file as $row_index => $line) {
    if($row_index === 0) continue;
    if($row_index === 1) {
      foreach($line as $val) {
        $keys[] = $val;
      }
    } else {
      $arr = array();
      foreach($line as $col_index => $val) {
        if($keys[$col_index] === 'view') {
          if($val === '0') break;
        } else {
          $arr[$keys[$col_index]] = $val;
        }
      }
      if(count($arr)) {
        $map[] = $arr;
      }
    }
  }
  foreach($map as $key => $val) {
    if(array_key_exists($key - 1, $map)) {
      $map[$key]['prevId'] = $map[$key - 1]['id'];
    }
    if(array_key_exists($key + 1, $map)) {
      $map[$key]['nextId'] = $map[$key + 1]['id'];
    }
  }
  fclose($temp);
  $file = null;
  return $map;
}
$csv_data = file_get_contents('data.csv', "id,name,age\n0,taro,20,\n1,jiro,25,\n2,saburo,30");
$data     = csv_to_map($csv_data);
header('Content-Type: application/json; charset=UTF-8');
header('X-Content-Type-Options: nosniff');
echo json_encode($data, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP);