presto-parquet/src/main/java/io/prestosql/parquet/reader/ParquetColumnChunk.java/ParquetColumnChunk/readDictionaryPage
class ParquetColumnChunk:    private DictionaryPage readDictionaryPage(PageHeader pageHeader, int uncompressedPageSize, int compressedPageSize)
    {
        DictionaryPageHeader dicHeader = pageHeader.getDictionary_page_header();
        return new DictionaryPage(
                getSlice(compressedPageSize),
                uncompressedPageSize,
                dicHeader.getNum_values(),
                getParquetEncoding(Encoding.valueOf(dicHeader.getEncoding().name())));
    }