presto-parquet/src/main/java/io/prestosql/parquet/reader/PageReader.java/PageReader/readDictionaryPage
class PageReader:    public DictionaryPage readDictionaryPage()
    {
        if (compressedDictionaryPage == null) {
            return null;
        }
        try {
            return new DictionaryPage(
                    decompress(codec, compressedDictionaryPage.getSlice(), compressedDictionaryPage.getUncompressedSize()),
                    compressedDictionaryPage.getDictionarySize(),
                    compressedDictionaryPage.getEncoding());
        }
        catch (IOException e) {
            throw new RuntimeException("Error reading dictionary page", e);
        }
    }