JPH02108119A - data compression device - Google Patents

Abstract

PURPOSE:To enable efficient data storage by providing a compressing means which has >=1 data compression means and data noncompression means and a compression decision means which decides the compressibility of data by the compressing means. CONSTITUTION:A data compressing device 6 is loaded previously in a RAM 5 by a CPU 1 and a user sends a compression instruction from K/B2, so that the data compressing device 6 receives data to be compressed from the CPU 1. Then a data compressing means 7 for the data and a decision means 8 for the compression result perform a series of compressing operations for the data and a data updating means 9 outputs the compressed data to a disk device. Consequently, the best compressed data or noncompressed data is obtained and the efficient data storage is enabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the registration, deletion, and registration of data in various disk devices.
The present invention relates to a data compression device when performing changes, etc.

[Background Art 1] Recently, with the development and spread of word processors, image scanners, high-resolution screens, etc., there is a tendency for the capacity and quantity of various types of data to increase when handling document data, image data, screen data, etc. Along with this, various data compression devices have been used to reduce data.

However, data compression requires control data to indicate compression, and the data compression device is not necessarily effective when dealing with complex or unique data patterns; There was also an increase in

For this reason, although the capacity of various disk devices such as floppy disks and RAM disks is increasing, portable and compact devices often have limited capacity and can easily fill up their disks. It was becoming something like that.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the disadvantage that the best data compression device cannot be obtained as described above. It is an object of the present invention to provide a data compression device that eliminates such drawbacks and performs efficient data storage.

[Means for Solving the Problems 1] A data compression device of the present invention includes a disk device for storing a plurality of data groups, and a data updating means for inputting and outputting data to and from the disk device. hand,
It is characterized by comprising a compression means having one or more data compression means and data non-compression means, and compression determination means for determining the degree of compression of data by the compression means.

[Function] In the present invention, when data processing is required, compression work is performed using a compression means having a plurality of compression means and a non-compression means, and the compression determination means selects the best compressed data. Alternatively, obtain uncompressed data and input/output the compressed data.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention, in which a central processing unit (hereinafter referred to as CPtJ) 1 processes data input from a keyboard (hereinafter referred to as /B) 2. Based on V
Data to be displayed is output to the RAM 3, and the result is displayed on a display device (eg, CRT, LCI) 4. On the other hand, a data compression device 6 is preloaded into the RAM 5 by the CPU 1, and when the user issues a compression instruction from the controller/B2, the data compression device 6 is loaded by the CPU 1.
Data to be compressed from 1 (e.g. VRAM3 data)
The receiver receives the data and applies data compression means 7 to the data.
The compression result determining means 8 executes a series of compression operations, and the data updating means 9 outputs the compressed data to a disk device (for example, a floppy disk).

FIG. 2 is a block diagram that further embodies the data compression device 6 shown in FIG.
The raw data 21 written in 3 and to be compressed from now on is processed by the compression section (1123,
The compression unit (2) 24° is composed of a compression unit (n) 25 and a non-compression unit 26, and the compression result of each compression unit is determined by the compression determination unit 27, and the best compression unit (X
) is selected and output as compressed data 28.

Next, the raw data 21, the compression section (1) 23, and the compression section (2) 24 will be specifically given, and the data compression effect will be described.

Figure 3 shows an example of compression means. The compression section (1), which uses the following compression means, is an advantageous means when the same data is continuous. This is done by means of compression.

The first byte is a control byte, the MS81 bit of the control byte indicates the type of control byte, and the following 7 bits indicate the number n of data. The same data is n bytes (2≦n≦1
27) The conversion means 32 is used when the same data is continuous, and the conversion means 31 is used when the same data is not continuous. The compression unit (2) is a means that is advantageous when data of 00h and FFh are continuous, and is performed by the following compression 0 means. The first byte is a control byte, the MS82 bit of the control byte indicates the type of control byte, and the following 6 bits indicate the number of data m.
or indicates data m. When the data is FFh and one or more consecutive pieces, the converting means 33 is used; when the data is 00h and one or more pieces are consecutive, the converting means 34 is used;
When the MSB2 bit is OO other than Oh, FFh, the conversion means 36 is used, and at other times (ooh, pFh, M
When the SB2 bit is not OOl), the conversion means 35 is used.6 The non-compression means uses the data as it is without processing it.

FIG. 4 shows the compression unit (1) 23, compression unit (2) 24, which is shown as the compression means in FIG. A state in which each of the non-compressing units 26 executes compression is shown. 80h
For data consisting of 6 consecutive bytes, the compression section (1) 23 compresses it to 2 bytes, the compression section (2) 24 compresses it to 7 bytes, and the non-compression section 26 compresses it to 6 bytes (41 ), OOh is 6 consecutive bytes of data, it is compressed to 2 bytes using compression section (1) 23, 1 byte when using compression section < 2) 24, and 6 bytes when using non-compression section 26. (42).

Furthermore, as unique data, 80h, 00h, 8oh
, ooh, soh, ooh are 6 bytes of data, but if the compression unit (1) 23 is used, it becomes 7 bytes.

If the compression section (2) 24 is used, the data is compressed to 9 bytes, and if the non-compression section 26 is used, it is compressed to 6 bytes (43).

FIG. 5 shows a situation in which the compression determining means 27 makes a determination upon receiving the result of the compressed data by the compressing means 22 of FIG. (2) 24 and the uncompressed part 26 each have 2.7.6 bytes, and it is determined that the compressed part (1) 23 is the best. In the case of raw data (2) 42, the compression unit (1) 23. The compression part (2) 24 and the non-compression part 26 each have 2.1.6 bytes, and it is determined that the compression part (2) 24 is the best. In the case of raw data (3) 43, the compression section (1) 23, compression section (2) 24, and non-compression section 26 each have 7.9.6 bytes, and it is determined that the non-compression section 26 is the best.

Finally, the best compressed data can be obtained by this compression determining means 27. The data updating means 9 in FIG.
By outputting this compressed data 28 to the disk device IO, the best compression method is selected and the data capacity is reduced, and even if the degree of compression is the worst, a non-compression method is selected and the compression is better than the raw data 21. The data 28 will no longer become large. ′ [Effect of the invention] As explained above, according to the present invention, when handling document data, image data, screen data, etc., even if the capacity and quantity of the various data increases, one or more data By providing a compression means having a compression means and a data non-compression means, and a compression determination means for determining the degree of compression of data by the compression means, the best data compression means can be obtained and efficient data storage can be achieved. It becomes possible to provide data compression equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 to 5 are schematic diagrams showing embodiments of the present invention, FIG. 2 is a block diagram showing a data compression method, and FIG. 3 is a block diagram showing an embodiment of the present invention. 4 shows an example of the implementation of the data compression method, and FIG. 5 shows an example of the implementation of the compression determining means. l ・ ・ ・ 2 ・ ・ ・ 3 ・ ・ 4 ・ ・ ・ 5 ・ ・ ・ 6 ・ ・ ・ 10 ・ ・ ・ PU K/B RAM Display device AM Data compression device Disk device Applicant Seiko Epson Corporation Agent Patent Attorney Kisanbe Suzuki (1 other person) Hanbetsu (1 person)
) Gomari (2) Non-IL ellipsoid raw data (1) Sex, take (3)

Claims (1)

[Claims] A compression device having one or more data compression means and data decompression means in a device having a disk device for storing a plurality of data groups and a data update means for inputting and outputting data to and from the disk device. 1. A data compression apparatus, comprising: means for determining the degree of compression of data by said compression means; and compression determining means for determining the degree of compression of data by said compression means.