Editing Deflate (section)

== Encoder–compressor ==
During the compression stage, it is the ''encoder'' that chooses the amount of time spent looking for matching strings. The zlib/gzip [[reference implementation]] allows the user to select from a sliding scale of likely resulting compression-level vs. speed of encoding. Options range from <code>0</code> (do not attempt compression, just store uncompressed) to <code>9</code> representing the maximum capability of the reference implementation in zlib/gzip.

Other Deflate encoders have been produced, all of which will also produce a compatible [[bitstream]] capable of being decompressed by any existing Deflate decoder. Differing implementations will likely produce variations on the final encoded bit-stream produced. The focus with non-zlib versions of an encoder has normally been to produce a more efficiently compressed and smaller encoded stream.

=== Deflate64, Enhanced Deflate ===
Deflate64, specified by PKWARE, is a proprietary variant of Deflate. It's fundamentally the same algorithm. What has changed is the increase in dictionary size from 32&nbsp;KB to 64&nbsp;KB, an extension of the distance codes to 16&nbsp;bits so that they may address a range of 64&nbsp;KB, and the length code, which is extended to [[16-bit computing|16-bit]], so that it may define lengths of three to 65,538 bytes.<ref>{{Cite web |url=http://www.binaryessence.com/dct/imp/en000225.htm |title=Binary Essence – Deflate64 |access-date=22 May 2011 |archive-url=https://web.archive.org/web/20170621195505/http://www.binaryessence.com/dct/imp/en000225.htm |archive-date=21 June 2017 |url-status=bot: unknown}}</ref> This leads to Deflate64 having a longer compression time, and potentially a slightly higher compression ratio, than Deflate.<ref>{{Cite web |url=http://www.binaryessence.com/dct/apc/en000263.htm |title=Binary Essence – "Calgary Corpus" compression comparisons |access-date=22 May 2011 |archive-url=https://web.archive.org/web/20171227131819/http://www.binaryessence.com/dct/apc/en000263.htm |archive-date=27 December 2017 |url-status=bot: unknown}}</ref> Several free and/or open source projects support Deflate64, such as [[7-Zip]],<ref>{{Cite web|url=https://sevenzip.osdn.jp/chm/cmdline/switches/method.htm|title=-m (Set compression Method) switch|website=sevenzip.osdn.jp|access-date=2023-01-21|archive-date=2022-04-09|archive-url=https://web.archive.org/web/20220409225619/https://sevenzip.osdn.jp/chm/cmdline/switches/method.htm|url-status=dead}}</ref> while others, such as [[zlib]], do not, because the procedure is proprietary,<ref>History of Lossless Data Compression Algorithms – [http://ieeeghn.org/wiki/index.php/History_of_Lossless_Data_Compression_Algorithms#DEFLATE64 Deflate64]</ref> and the performance increase over Deflate is small.<ref>zlib FAQ – [https://www.zlib.net/zlib_faq.html#faq40 Does zlib support the new "Deflate64" format introduced by PKWare?]</ref>