官术网_书友最值得收藏!

  • D Cookbook
  • Adam D. Ruppe
  • 251字
  • 2021-07-16 11:50:47

Using the std.zlib compression

Phobos provides a wrapper for the common zlib/gzip/DEFLATE compression algorithm. This algorithm is used in the .zip files, the .png images, the HTTP protocol, the common gzip utility, and more. With std.zlib, we can both compress and decompress data easily.

How to do it…

Let's compress and decompress data by executing the following steps:

  1. Import std.zlib.
  2. Create an instance of Compress or UnCompress, depending on what direction you want to go.
  3. Call the compress or uncompress methods for each block of data, concatenating the pieces together as they are made.
  4. Call flush to get the last block of data.

The code is as follows:

void main() {
  import std.zlib, std.file;
  auto compressor = new Compress(HeaderFormat.gzip);
  void[] compressedData;
  compressedData ~= compressor.compress("Hello, ");
  compressedData ~= compressor.compress("world!");
  compressedData ~= compressor.flush();
  std.file.write("compressed.gz", compressedData);
}

Running the program will create a file, compressed.gz, which can be unzipped to become a text file with Hello, world!.

How it works…

The std.zlib module doesn't follow exactly the same pattern as std.digest (the implementation of std.zlib was written before ranges were incorporated into Phobos), but it is a very simple API. It works with one block of data at a time, returning the compressed or uncompressed block. When finished, the flush method clears any partial blocks, returning the final piece of data.

There are also convenience functions, compress and uncompress, that can perform the operation in a single function call if you have all the data available as a single array at once.

主站蜘蛛池模板: 伊川县| 阳曲县| 稷山县| 屏边| 叙永县| 库伦旗| 遂川县| 北碚区| 盐津县| 茶陵县| 洛浦县| 屏边| 临泽县| 平谷区| 宝坻区| 资中县| 五家渠市| 外汇| 黄浦区| 抚远县| 新乡市| 青冈县| 凯里市| 澄迈县| 渭源县| 五华县| 巴彦县| 伊宁市| 阳谷县| 仙居县| 台东县| 高州市| 无为县| 镇坪县| 聊城市| 巴青县| 桦川县| 平昌县| 屏东县| 云南省| 永济市|