Fast Lossless Compression Method for Embedded Device Memory Data
An embedded device, memory data technology, applied in the field of data processing, can solve the problems of inapplicability of LZO compression method and compression format, inability to effectively improve memory utilization, slow compression and decompression speed, etc., to improve memory data storage. The effect of capacity and utilization, good compression ratio, simple compression format
Active Publication Date: 2017-06-16
XIDIAN UNIV
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The disadvantage of this method is that since the memory "paging mechanism" was proposed, the default size of the memory page is set to 4096 bytes, that is, 4KB
In order to facilitate memory data management, the memory data should be compressed page by page, and the initial design purpose of LZO is to compress data with variable length. When compressing memory data, it can only achieve a very low compression rate and cannot effectively improve memory utilization. rate, and the compression and decompression speeds are slow
Therefore, for memory data, the current LZO compression method and compression format cannot be applied
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[0018] Below in conjunction with figure, the present invention is described in further detail:
[0019] refer to figure 1 , the implementation steps of the present invention are as follows:
[0020] Step 1: Read a memory page from the memory data packet of the embedded device, that is, read the memory page page by page according to the page size of 4KB.
[0021] Step 2: Read four characters from the read memory page, and perform the first hash operation, that is, calculate the key value through the first hash function, which is the first in the current LZO lossless compression method a hash function.
[0022] Step 3: Determine whether the position of the character is legal according to the key value in step 2. If it is legal, go to step 4. If not, update the hash table. The hash table is a data structure directly accessed according to the key value, and then return step2.
[0023] The legality mentioned means that every position stored in the hash table can only be accesse...
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The invention discloses a quick lossless compression method of memory data of an embedded device and mainly solves the problem that the existing compression method has low memory page compression speed. The method is mainly characterized in that two compression formats suitable for memory page data are designed: in the first format, a first byte records character repeated length, shift distance and new character length, and residual new character length, new characters and residual shift distance are recorded in order from the second byte; in the second format, the first byte records a compression format mark, shift distance and new character length, and residual new character length, new characters, character repeated length and residual shift distance are recorded in order from the second byte. Compared with the existing LZO (Lempel-Ziv-Oberhumer) lossless compression method, the method has the advantages that compression and decompression speed of memory page data is increased, a higher compression ratio is obtained, the embedded device has higher memory data storage capacity and availability, and the method is applicable to limited storage embedded devices.
Description
technical field [0001] The invention belongs to the technical field of data processing, and relates to a data compression method for embedded device memory data. The invention adopts a new data compression format according to the characteristics of memory data during data compression to improve the compression speed, and can be used in embedded devices with limited storage. in the device. Background technique [0002] Memory is one of the important parts of the computer, it is a bridge to communicate with the CPU. All programs in a computer run in memory. The performance of the memory has a great impact on the computer, and in embedded portable devices with limited volume and storage capacity, the impact of the memory on the device performance and user experience is particularly prominent. In recent years, with the development of the mobile Internet, embedded portable devices such as mobile phones and tablet computers have become a necessary communication tool for people. ...
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IPC IPC(8): H03M7/30
Inventor 宋彬李慧玲秦浩裴远
Owner XIDIAN UNIV