convert CT1 price modifiers to CT2

gistfile1.php

<?php

  	$fieldtypes = array(
			'ct_price_mod' => 'cartthrob_price_modifiers',
			'ct_coupon' => 'cartthrob_discount',
			'ct_items' => 'cartthrob_order_items',
			'ct_matrix_pq' => 'cartthrob_price_quantity_thresholds',
		);
		
		foreach ($fieldtypes as $field_type => $new_field_type)
		{
			//get fields that match this old field type
			$fields = get_instance()->db->select('field_id')
					       ->where('field_type', $field_type)
					       ->get('channel_fields')
					       ->result();
			
			foreach ($fields as $field)
			{
				$field_data = NULL;
				
				//get the entries with field data for this field id
				$entries = get_instance()->db->select('entry_id, field_id_'.$field->field_id)
						      ->where('field_id_'.$field->field_id.' !=', '')
						      ->get('channel_data')
						      ->result();
				
				foreach ($entries as $entry)
				{
					if ($field_type === 'ct_items')
					{
						$data = @unserialize($entry->{'field_id_'.$field->field_id});
						
						if (is_array($data))
						{
							foreach ($data as $row_id => $row)
							{
								$insert = array(
									'order_id' => $entry->entry_id,
									'row_order' => $row_id,
								);
								
								foreach (array('entry_id', 'title', 'quantity', 'price') as $key)
								{
									$insert[$key] = (isset($row[$key])) ? $row[$key] : '';
									unset($row[$key]);
								}
								
								$insert['extra'] = (count($row) > 0) ? base64_encode(serialize($row)) : '';
								
								get_instance()->db->insert('cartthrob_order_items', $insert);
							}
							
							$field_data = 1;
						}
					}
					else if ($field_type === 'ct_price_mod')
					{
						$data = @unserialize($entry->{'field_id_'.$field->field_id});
						
						if (is_array($data))
						{
							foreach ($data as &$row)
							{
								if (isset($row['option']))
								{
									$row = array_merge(array('option_value' => $row['option']), $row);
									
									unset($row['option']);
								}
							}
							
							$field_data = base64_encode(serialize($data));
						}
					}
					else
					{
						$field_data = base64_encode($entry->{'field_id_'.$field->field_id});
					}
					
					if ( ! is_null($field_data))
					{
						get_instance()->db->update(
							'channel_data',
							array('field_id_'.$field->field_id => $field_data),
							array('entry_id' => $entry->entry_id)
						);
					}
				}
			}
			
			get_instance()->db->update('channel_fields', array('field_type' => $new_field_type), array('field_type' => $field_type));
		}