/** * Reads and decompresses a dictionary page for the given column chunk. * * Returns null if the given column chunk has no dictionary page. * * @param meta a column's ColumnChunkMetaData to read the dictionary from * @return an uncompressed DictionaryPage or null * @throws IOException if there is an error while reading the dictionary */ DictionaryPage readDictionary(ColumnChunkMetaData meta) throws IOException { if (!meta.getEncodings().contains(Encoding.PLAIN_DICTIONARY) && !meta.getEncodings().contains(Encoding.RLE_DICTIONARY)) { return null; } // TODO: this should use getDictionaryPageOffset() but it isn't reliable. if (f.getPos() != meta.getStartingPos()) { f.seek(meta.getStartingPos()); } PageHeader pageHeader = Util.readPageHeader(f); if (!pageHeader.isSetDictionary_page_header()) { return null; // TODO: should this complain? } DictionaryPage compressedPage = readCompressedDictionary(pageHeader, f); BytesInputDecompressor decompressor = options.getCodecFactory().getDecompressor(meta.getCodec()); return new DictionaryPage( decompressor.decompress(compressedPage.getBytes(), compressedPage.getUncompressedSize()), compressedPage.getDictionarySize(), compressedPage.getEncoding()); }
/** * Reads and decompresses a dictionary page for the given column chunk. * * Returns null if the given column chunk has no dictionary page. * * @param meta a column's ColumnChunkMetaData to read the dictionary from * @return an uncompressed DictionaryPage or null * @throws IOException if there is an error while reading the dictionary */ DictionaryPage readDictionary(ColumnChunkMetaData meta) throws IOException { if (!meta.getEncodings().contains(Encoding.PLAIN_DICTIONARY) && !meta.getEncodings().contains(Encoding.RLE_DICTIONARY)) { return null; } // TODO: this should use getDictionaryPageOffset() but it isn't reliable. if (f.getPos() != meta.getStartingPos()) { f.seek(meta.getStartingPos()); } PageHeader pageHeader = Util.readPageHeader(f); if (!pageHeader.isSetDictionary_page_header()) { return null; // TODO: should this complain? } DictionaryPage compressedPage = readCompressedDictionary(pageHeader, f); BytesInputDecompressor decompressor = options.getCodecFactory().getDecompressor(meta.getCodec()); return new DictionaryPage( decompressor.decompress(compressedPage.getBytes(), compressedPage.getUncompressedSize()), compressedPage.getDictionarySize(), compressedPage.getEncoding()); }