Summary of instance codes about compression algorithms

Foreword LZ77 algorithm is lossless compression algorithm, by the Israeli Abraham Lempel published in 1977. LZ77 is a typical dictionary-based compression algorithm, and many compression techniques are now based on LZ77. In view of its position in the field of data compression, this article will be combined with the image and source details of its principles. Introduction: First introduce several professional terminology. 1.lookahead buffer (does not know how to express in Chinese, temporarily known as the coding area): Waiting for the coded area 2. Search buffer: The area that has already been coded, searching for buffers 3. Sliding window: Specifies the size of a window, including the "Search buffer" (left) + "to encode" (right) Next, the specific coding process: In order to encode the area to encode, The encoder locates the search buffer in the sliding window until a matching string is found. The distance between the start string of the matching string and the buffer to be encoded is called the offset value, and the length of the matching string is called the match length. When the encoder is encoded, it searches the search area until the maximum match string is found and outputs (O, L), where O is the offset value and L is the matching length. Then the window

1. Graphic details LZ77 compression algorithm coding Python implementation principle

Introduction: Preface LZ77 algorithm is lossless compression algorithm, by the Israeli Abraham Lempel published in 1977. LZ77 is a typical dictionary-based compression algorithm, and many compression techniques are now based on LZ77. In view of its position in the field of data compression, this article will be combined with the image and source details of its principles. Introduction: First introduce several professional terminology. 1.lookahead buffer (does not know how to express in Chinese, temporarily known as the coding area): Waiting for the coded area 2. Search buffer: The area that has been encoded, searching for buffers 3. Slip.

2. LZW compression algorithm

Description: LZW compression algorithm

3. A perfect php zip compression class Code _php tutorial

Introduction: A Perfect PHP zip compression class code. This program can be quickly implemented to our files using PHP compression class compressed into our thinking zip, or rar compression package, suffix can be customized oh, compression algorithm is from a foreign site

4. [GD] Create a BMP format picture (imagebmp) _php Tutorial

Introduction: [GD] generates a BMP format picture (imagebmp). GD library does not produce BMP image function, so wrote a, this function has a compression algorithm is not written, but already enough. The students who need it can take a look. int image

5. PHP program accelerated exploration of compressed output gzip_php tutorial

Description: PHP program accelerates exploration of compressed output gzip. Using the Mod_gzip module in Apache, we can use the GZIP compression algorithm to compress the Web content published by the Apache server before it is transferred to the client's browser. If it is plain text

6. A perfect php zip compression class Code

Introduction: A Perfect PHP zip compression class code. This program can be quickly implemented to our files using PHP compression class compressed into our thinking zip, or rar compression package, suffix can be customized oh, compression algorithm is from a foreign site

7. [GD] Create a BMP format picture (imagebmp)

Introduction: [GD] generates a BMP format picture (imagebmp). GD library does not produce BMP image function, so wrote a, this function has a compression algorithm is not written, but already enough. The students who need it can take a look. int image

8. Make it faster to transfer large files remotely

Introduction: I was doing tests on two virtual machines. If the traditional SCP remote copy, the speed is relatively slow, now using LZ4 compression transmission. The LZ4 is a very fast lossless compression algorithm that compresses at a single-core 300mb/s and can be extended

9. Rman Backup Optimization Ideas

Introduction: This chapter does not talk about the principle of rman backup, only provide some ideas 1.oracle11g select compression algorithm for intermediate; 2. Increase the channel for Rman backup. The above two practices, increase CPU utilization, reduce IO 3. Specify the rate parameter this number and channel sum do not exceed the ioPS of the hard disk, so as not to cause IO wait

Unity3d-Is there a symmetric compression algorithm for C # (Unity) and PHP?

Summary: Recently developed the game Project client uses unity, while the server side uses PHP, want to compress the client and the server to transfer the amount of communication data. What are the available compression decompression algorithms in unity? Is there a symmetric compression decompression API available on the PHP side? Thank you ~

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