Brotli を用いた静的コンテンツ配信最適化と Accept-Encoding: br について | blog.jxck.io
Intro High Sierra に乗る Safari 11 で Brotli 対応がされるということで、メジャーブラウザの Brotli 対応が概ね揃うことになる。 そこで、本サイトも Brotli による静的コンテンツ配信に対応した。 brotli brotli は Google が開発した新しい圧縮形式である。 Brotli Compressed Data Format LZ77 とハフマン符号化を合わせたものであり、元々は WOFF2 の仕様の一部として作られたものが、汎用化されたものである。 過去に公開されている zopfli と比べても、さらに圧縮率が 20-26% 向上しており、解答速度は zlib 相当とされている。 この効果に寄与する特徴的な要因として、仕様に含まれる辞書が挙げられる。 Static Dictionary 圧縮アルゴリズムは、簡単に言えば頻出する一致部分
Gzip 1.7 Released With Synchronous & Rsyncable Options - Phoronix
Show Your Support: Have you heard of Phoronix Premium? It's what complements advertisements on this site for our premium ad-free service. For less than $4 USD per month, you can help support our site while the funds generated allow us to keep doing Linux hardware reviews, performance benchmarking, maintain our community forums, and much more. Gzip 1.7 Released With Synchronous & Rsyncable Options
Smaller and faster data compression with Zstandard
People are creating, sharing, and storing data at a faster rate than at any other time in history. When it comes to innovating on storing and transmitting that data, at Facebook we're making advancements not only in hardware — such as larger hard drives and faster networking equipment — but in software as well. Software helps with data processing through compression, which encodes information, lik
SWFバイナリ編集のススメ番外編 (zlib 伸張) 前編 | GREE Engineering
こんにちは。アプリケーション基盤チームのよやと申します。 バイナリの目利きや書き換えを主な業務フィールドとし、1% でも多くのユーザの皆様にサービスをお届けする為、より良質のバイナリを探し求める毎日です。 SWF の番外編として zlib 伸張について２回のブログに分けて解説します。(圧縮処理は対象外です) 前編の今回は概要についてお話し、具体的な実装は後編で扱う予定です。 はじめに SWF フォーマットは zlib 圧縮を多用します。例えば、GIF/PNG 画像は独自画像形式(DefineBitsLossless の BitmapPixelData)に変換後 zlib 圧縮して格納します。 http://labs.gree.jp/blog/2010/12/1902/ SWFバイナリ編集のススメ第五回 (PNG) SWF バイナリの中の zlib 圧縮されたデータが怪しい場合に、zlib
カスタムハフマン符号 - 七誌の開発日記
ZIP勉強会（id:n7shi:20110529）を開催しましたが、時間の都合もありカスタム（動的）ハフマン符号については「RFC 1951を読んでください」で説明を省略しました。IO_Zlib開発者のid:yoyaさんからコメントを頂いたので、某「例示は理解の試金石」を実践してみました。 よやさんのまとめ id:yoya:20110726:io_zlib .NETのDeflateStreamはどんな短いものでもカスタムハフマンで圧縮します。それを利用して "aaaaa" というASCII文字列をカスタムハフマン圧縮してみます。 open System.IO open System.IO.Compression open System.Text let fs = new FileStream("test.bin", FileMode.Create) let ds = new Deflate
Fighting Cancer: The Unexpected Benefit Of Open Sourcing Our Code
Fighting Cancer: The Unexpected Benefit Of Open Sourcing Our Code07/08/2015 Recently I was contacted by Dr. Igor Kozin from The Institute of Cancer Research in London. He asked about the optimal way to compile CloudFlare's open source fork of zlib. It turns out that zlib is widely used to compress the SAM/BAM files that are used for DNA sequencing. And it turns out our zlib fork is the best open s
GZinga: Seekable and Splittable Gzip
Generally, data compression techniques are used to conserve space and network bandwidth. Widely used compression techniques include Gzip, bzip2, lzop, and 7-Zip. According to performance benchmarks, lzop is one of the fastest compression algorithms, while bzip2 has a high compression ratio but is very slow. Gzip offers the lowest level of compression. Gzip is based on the DEFLATE algorithm, which
Random access to zlib compressed files
Zlib / gzip is probably the most popular library/tool for general data compression. In zlib, there is an API gzseek() which places the file position indicator at a specified offset in the uncompressed file. However, whenever it gets called, it starts from the beginning of the file and reads through all the data up to the specified offset. For huge files, this is very slow. It is actually possible
GZ-Sort: A utility for sorting really big files.
Nice app, but unfortunately limited to gzipped data. Would be a lo... sources are at github git clone https://github.com/keenerd/gz-sort; cd gz-sort; make; ./gz-sort -h Gz-sort sorts gzipped data files. Really really big gzipped data files that I couldn't figure out how to wrangle with gnu-sort. After heavy tweaking gnu-sort can do some very large files indeed, but with poor big-O disk patterns. I
zindex - index your compressed text files
Scratching your own itch @mattgodbolt / @mattgodbolt My problem 5000+ read-only archived JSON log files on NFS Average 450MiB gzipped, 4GiB uncompressed Need to find entries by a unique ID zgrep $ zgrep -E '^\{"eventId":63181572,' audit.log.gz {"eventId":63181572,...} Takes 14 seconds zgrep has to uncompress every byte of the file to search it! Could index file ...but then would need to be able to
jQuery file size
Note: The gzipped and Zopflinated file sizes refer to the total byte size of the file after compressing it using gzip or Zopfli with the default settings. For gzip, this boils down to gzip -6 file.js — the default compression level is 6 on a scale from 1 (fastest, but less compression) to 9 (slowest, but best compression). For Zopfli, 15 iterations are performed (i.e. the default): zopfli --i15 fi
Improving compression with a preset DEFLATE dictionary
Improving compression with a preset DEFLATE dictionary03/30/2015 A few years ago Google made a proposal for a new HTTP compression method, called SDCH (SanDwiCH). The idea behind the method is to create a dictionary of long strings that appear throughout many pages of the same domain (or popular search results). The compression is then simply searching for the appearance of the long strings in a d
How gzip uses Huffman coding
I wrote a blog post quite a while ago called gzip + poetry = awesome where I talked about how the gzip compression program uses the LZ77 algorithm to identify repetitions in a piece of text. In case you don’t know what LZ77 is (I sure didn’t), here’s the video from that post that gives you an example of gzip identifying repetitions in a poem! I thought this was a great demonstration, but it’s only
School - JA-VA Code
Java – the most common programming language, it is not difficult to learn, so it is suitable for those who first approached the study of programming. Introduction Java course is designed for those who are just starting their way in the IT industry and have no idea about the basics of programming. During the course, students will learn to create Java applications and gain an understanding of OOP pr
Deflate (gzip) のアルゴリズムを視覚化してみた
のような感じにエンコードされることが分かります。 自分の好きなデータで試すことができて便利！という話でした。 PS. 以下は実行結果です。 % make % gzip < alice.txt > alice.txt.gz % ./puff -10 alice.txt.gz puff() succeeded uncompressing 1328 bytes 8 compressed bytes unused inpos=406,inbits=224,outpos=0,outbytes=45 41 6c 69 63 65 20 77 61 73 20 62 65 67 69 6e 6e 69 6e 67 20 74 6f 20 67 65 74 20 76 65 72 79 20 74 69 72 65 64 20 6f 66 20 73 69 74 74 A l i c e w a s b
Intel Makes Major Zlib Performance Improvements - Phoronix
Intel Makes Major Zlib Performance Improvements Written by Michael Larabel in Intel on 26 November 2013 at 02:05 PM EST. 7 Comments Intel's Open-Source Technology Center has prepared a set of thirteen patches against Zlib to sharply improve the deflate performance. Jim Kukunas of Intel OTC published the set of 13 patches on Monday that include medium and quick deflate strategies, a faster hash fun
Compression Options in Hadoop - A Tale of Tradeoffs
Yahoo! is one of the most-visited web sites in the world. It runs one of the largest private cloud infrastructures, one that operates on petabytes of data every day. Being able to store and manage that data well is essential to the efficient functioning of Yahoo!`s Hadoop clusters. A key component that enables this efficient operation is data compression. With regard to compression algorithms, the
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Why isn’t it possible to read gzip files from the middle?
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