JPH03162134A - Compressing/expanding system for communication data - Google Patents

Abstract

PURPOSE:To shorten the data transfer time on a communication line by curtailing the communication data by using a compression processing program. CONSTITUTION:A system A is constituted by adding a compression processing program 2A and an expansion processing program 3A to a communication program 1A and a communication control mechanism 4A, and a system B is also constituted by adding a compression processing program 2B and an expansion processing program 3B to a communication control mechanism 4B and a compression processing program 2B. In such a state, in the case the same character-string of the maximum 4096 bytes in which one character or two characters in communication data are continued is compressed to 4 bytes, and the character-string is a numerical type, a different character-string of the maximum 9 bytes is compressed to 4 bytes or below, and its communication data is expanded and restored at the time of reception. In such a way, the time required for the transmission/reception processing of the communication data is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication data compression/expansion method, and more particularly to transmission and reception of communication data in a data transfer method via a communication line.

[Conventional technology]

Conventionally, when communicating data with other systems, the content of the communication data was sent and received either in its original format or in a compressed format using information indicating data attributes. [Problem to be solved by the invention] In the conventional method described above, when communication data is uncompressed, communication data and contents are transmitted and received without being processed. The time required for the transmission and reception processing depends on the amount of communication data. Therefore, even if consecutive identical character strings exist, the time required to process them remains the same. Another disadvantage is that compression requires information indicating the attributes of each type of communication data. [Means for Solving the Problems] The communication data compression/decompression method of the present invention does not require information indicating attributes in the data,
Compressing identical character strings of up to 4096 bytes of consecutive characters or two characters into 4 bytes or less, and compressing different character strings of up to 9 bytes into 5
It has means for compressing the compressed communication data to less than a byte, and means for decompressing and restoring the compressed communication data using logic opposite to that of compression upon reception.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows the overall structure of an embodiment of the present invention. In Fig. 1, system A is simplified by adding a compression processing program (2A) and a decompression processing program (3A) to a communication program (LA) and a communication control mechanism (4A). It is constructed by adding a compression processing program (2B) and a decompression processing program (3B) to a program (IB) and a communication control mechanism <4B>.System A and system B are connected via a communication circuit. System A
An example will be explained in which a communication program (IA) residing in system B performs data communication with a communication program (IB) residing in system B. A program existing in system A (I
A) compresses the communication data transmission request <2A
>, the communication data is processed by the compression processing program (2
At A), data is compressed using the data compression method described later, and control is passed to the communication control mechanism (4, A). Communication control R structure <4A> transmits compressed communication data to system B via a communication line. System B communication controller f
# (4B) receives the compressed communication data and passes the communication data to the decompression processing program (3B). The decompression program (3B) decompresses the compressed communication data using the data decompression method described later and converts it into the communication program (IB).
Pass communication data to. Next, the compression method used in the compression processing program (2A) of system A will be explained. Figure 2 shows part of the original data contained in certain communication data, which is data (IC) in which the same single character is consecutive.
It represents data in which two characters are consecutive (2C), data in which different numbers are consecutive (3C), and data that does not correspond to any of these three types (4C).

Figure 3 shows the results of compressing each data, and the data format shown in Figure 2 is 1 character compressed data (ID) and 2 characters.
Compressed character data (2D) and compressed numerical data (3D)
and uncompressed data (4D). These four types of compression formats will be explained.

■In character compression processing, the compressed characters of original data (IC) are compressed character field (1D) of compressed data (1D).
3D). The number of compressed characters is the compressed data (I
D> is expressed in the number of compressed characters field (12D). Also, compressed data (1
D) is expressed in the control code field (IID).

The size of the compressed character count field (12D) is 4 bits when the original data is 16 bytes or less, and 12 bits when it is 17 bytes or more and 4096 bytes or less, and its identification is also expressed in the control code field (LID). 6 In 2-character compression processing, the compressed character of the source data (2C) is the compressed character field (2D) of the compressed data (2D).
3D). The number of compressed characters is compressed data (2
D) is expressed in the number of compressed characters field (22D). Also, to indicate the compressed data format, compressed data (2
D) is expressed in the control code field (21D).

The size of the compressed character count field (22D) is 4 bits when the original data is 16 bytes or less, and 12 bits when it is 17 bits or more and 4096 bytes or less, and its identification is also expressed in the control code field (21D). do. In the numerical compression process, continuous numerical type original data (3C) is regarded as a decimal number and converted into a hexadecimal number. The numerical value is the device field of the compressed data (3D) (
33D). The number of numbers is compressed data (
3D) in the number field (32D). Also, to indicate the compressed data format, compressed data (3D
) is expressed in the control code field (31D). The numeric field (33D) is 2 bytes when the original data number is 4 bytes or less, and 4 when it is 5 bytes or more and 9 bytes or less, and this identification is also the control code field (31D).
Expressed in.

In character processing that cannot be compressed, the original data (4C) is directly used as the uncompressed field (43) of the compressed data (4D).
Expressed as D). The number of uncompressed characters is displayed in the number of uncompressed characters field (42D). Also, to indicate the compressed data format, it is expressed in the control code field (41D) of the compressed data (4D). The size of the uncompressed character count field (42D> is 4 bits when the original data is less than 16 bytes, and 12 bits when it is more than 17 bytes and less than 4096 bytes, and its identification is also in the control code field (41D). express.

Original data (IE) shown in Figure 4 from the above four types of compression formats
will be expressed as compressed data (2E) after compression. Next, the decompression method used in the decompression processing program (3B) of system B will be explained.

Each compressed data (LD, 2D, 3D, 4D
, ) are decompressed and each original data (IC, 2C, 3
C, 4C). Each decompression format is the opposite of the compression format used in the compression program (2A) of System A described above. From the above four types of decompression methods, the compressed data (2E) in Figure 4 will be expressed as original data (IE) after decompression. [Effects of the Invention] As explained above, the present invention The data transfer time on the communication line is shortened by reducing the communication data by the processing program, and the conventional compression/expansion technology is used, in which the communication data is compressed by the compression processing program and decompressed by the decompression processing program. This has the effect of eliminating the need for information indicating attributes in necessary data.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing original data before transmission data is compressed and received data is expanded, and FIG. 3 is a diagram showing original data after transmission data is compressed. FIG. 4 is a diagram showing a comparison example of compressed data and decompressed data. A. B...System, IA, 1B...
... Communication program, 2A, 3B ... Compression program, 3A, 3B ... Decompression processing program, 4A, 4B ... Communication control device.

Claims (1)

[Claims] Between systems connected by a communication line, the same character string of up to 4096 bytes of one or two consecutive characters in the communication data can be compressed to 4 bytes, and if the character string is a numeric type, it can differ by up to 9 bytes. A method for compressing and decompressing communication data, comprising means for compressing a character string to 4 bytes or less, and means for decompressing and restoring the communication data upon reception.