A detailed introduction to data compression

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. Summary of instance codes for compression algorithms

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: Already coded area, search ...

2. 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.

3. Detailed PHP data compression, encryption and decryption (pack, unpack)

Introduction: Network communication, file storage often need to exchange data, in order to reduce network traffic, file storage size and encryption communication rules, often need to two-way encryption and decryption to ensure data security. The main function of this function in PHP is to use the pack and unpack function pack to compress the data into the string. Syntax: string Pack (string format, mixed [args]

4. Photoshop CS2 v9.0 Green Chinese version PHP Development Framework Summary Collection

Introduction: Photoshop CS2 v9.0 Green Chinese version: Photoshop cs2 v9.0 Green Chinese PHP Development Framework Summary collection: Development framework Wact http://wact.sourceforge.net/old PHP programming framework, Implemented many enterprise-level development patterns Horde http://www.horde.org/horde/provides a number of common libraries that can be used for parameter processing, data compression, browser detection, link tracking, and MIME. Support for the Pear Class Library is required, providing an API reference. Seagull Http://seagull.phpkitch

5. Speed up your page--Data compression _php tutorial

Introduction: Accelerating your page-data compression. Recently, my website is getting slower, not slow script execution time, the network transmission speed is slow. Know http1.1 support gzip encoded data, so try to compress your own page compression ... (In

6. PHP data compression, encryption and decryption (pack, unpack) _php tutorial

Introduction: PHP Data compression, encryption and decryption (pack, unpack). network communication, file storage often need to exchange data, in order to reduce network traffic, file storage size and encryption of communication rules, often need to two-way encryption to ensure that the data

7. PHP Streams (Stream) detailed introduction and use, phpstreams_php tutorial

Introduction: PHP Streams (Stream) detailed introduction and use, Phpstreams. PHP Streams (Stream) detailed introduction and use, Phpstreams PHP Streams is built-in core operations, probably the general developers rarely use, it is used for unified file, network, data compression and other class file

8. Two ways to turn on gzip compression in PHP Web programs

Introduction: gzip is a network data compression transmission skills, can let our bandwidth save about 70%, can greatly speed up the page opening speed, not only conducive to user experience, but also save a lot of bandwidth. General Apache, Nginx and so on in the configuration file can open the Gzip service. Let's talk about how to turn on the gzip compression service in the PHP Web program: The first gzip compression scenario 1, add the following code to the. htaccess: AddHandler application/x-httpd-php&

9. Speed up your page--data compression

Introduction: Accelerating your page-data compression. Recently, my website is getting slower, not slow script execution time, the network transmission speed is slow. Know http1.1 support gzip encoded data, so try to compress your own page compression ... (In

PHP data compression, encryption and decryption (pack, unpack)

Introduction: PHP Data compression, encryption and decryption (pack, unpack). network communication, file storage often need to exchange data, in order to reduce network traffic, file storage size and encryption of communication rules, often need to two-way encryption to ensure that the data

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