JP2604492B2 - Data compression processing method for sequential files - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] In the present invention, each record of a sequential file includes data in which the same character string as the previous record exists and in which the same character continues. And an efficient data compression processing method.

[Conventional technology]

Conventionally, a sequential file is compressed using compression means of the same character string of the preceding and succeeding records or compression means of the same continuous character, or compression using both compression means. I had to leave the file.

[Problems to be solved by the invention]

In the above-mentioned conventional technique, a drawback is that the data characteristics of each sequential file must be investigated or the compression efficiency must be investigated by processing both sequential files for each sequential file in order to select the compression means. was there. Further, in order to use both compression means, the compression sequential organization file created by one compression means must be compressed again by the other compression means.

[Means for solving the problem]

According to the present invention, in a data compression processing method for a sequential file having continuous data of the same character or the same character string data of a previous record, data is input one by one by taking data from the sequential file and storing the data in a work area prepared in advance. By comparing the means with the record just entered,
The stored record is divided into a portion of a type A field indicating that the record has the same character string data and a portion of a type B field indicating that the record is other than the type A field, and a compression instruction is sequentially issued for each field. A record dividing means for compressing the same character string before and after outputting when the field accompanying the compression instruction is type A, converts the type A field into compression information by a predetermined compression method, and outputs it to a previously prepared output area; Means and, when the field accompanying the compression instruction is of type B, when there is continuous data of the same character in the field of type B, the continuous character portion is compressed by a predetermined compression method. Information and compressed characters, and converts the discontinuous character string into predetermined uncompressed information and an uncompressed character string. The same continuous character compression means for outputting to the output area, and when outputting the compressed / uncompressed information and the compressed character / uncompressed character string to the output area, the compressed information of the same character string before and after is output to the output record. Information adding means for adding predetermined dummy information such that the compressed information of the same consecutive characters is located at the even-numbered position in the compressed information at odd-numbered positions in the compressed information. And a data output means for outputting the compressed record, which is activated at the end of the compression processing of each field and output to the output area, to a sequential file.

〔Example〕

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

FIG. 1 is a diagram showing the configuration of one embodiment of the present invention.
The compression processing method for sequential files is based on the data input means (10
1), a record dividing means (102), a preceding and succeeding identical character string compressing means (103), an identical continuous character compressing means (104), an information adding means (105), and a data output means (106). ing.

First, one record is input from the input sequential file by the data input means (101) and stored in the work area. Next, a field called type A which is the same character string as the previous record by the record dividing means (102),
Split the record into other fields called Type B. This type A field is converted into compression information by the same front and rear character string compression means (103) and set in the output area. In the field of type B, a continuous portion of the same character is converted into compression information and a compressed character by the same continuous character compression means (104) and set in an output area. Non-consecutive parts are converted into uncompressed information and an uncompressed character string and set in the output area. When the compression information is set in the output area, the information addition means (105) sets the compressed information of the same character string before and after in the odd-numbered position in the compressed information in the output record, Dummy information is added so as to be an even-numbered position. The compressed record created in the output area is output to a sequential file for output by the data output means (106). By making it possible to distinguish even numbers and odd numbers in this way, it is not necessary to use an identification code for determining whether the same character string is compressed information of consecutive same characters, and the compression efficiency can be improved.

2 to 8 show the data input means (10
Example of processing corresponding to 1), record dividing means (102), preceding and succeeding identical character string compressing means (103), identical continuous character compressing means (104), information adding means (105), and data output means (106) FIG.

A detailed description will be given in each flowchart. FIG. 2 is a flowchart of the data input means (101), in which one record is input from the sequential file and stored in the work area (201), after which control is passed to the record dividing means.

FIG. 3 is a flowchart of the record dividing means (102). If there is a character string identical to the previous record as a result of comparison with the previous record (301), the character string is extracted and set as a type A field (304 to 305). If they are not the same character string, the character string is extracted and set as a type B field (302 to 303). Steps 301 to 305 are repeated until all the field divisions of the data in the record are completed (306).

The records for which field division has been completed are subjected to the processing of FIGS. 4 and 5 for each field (307), and when the compression processing of each field is completed, the data output means (10)
6) Start (308).

FIG. 4 is a flow chart of the same character string compression means (103) before and after. The type of the received field is checked (401), and if it is type A, the information adding means (105)
After calling, set the compression information in the output area (40
2 to 403). Reference numerals 404 and 405 show examples before and after compression.

FIG. 5 is a flowchart of the same continuous character compression means (104). Check the type of the received field (50
1) If it is type A, the process is terminated; if it is type B, it is checked whether the same character is continuous (50).
2) If they are continuous, the information adding means is called, and only one character continuous with the compressed information is set in the output area (503 to 505). If the same character is not consecutive, take out the non-continuous character string and convert it to an uncompressed character string.
Set uncompressed information and uncompressed character string in the output area (50
6-508). Steps 502 to 508 are repeated until all compression processing in the field is completed (509). 510 and 511 show examples before and after compression.

FIG. 6 is a flowchart of the information adding means (105). Check the type of field currently being processed (60
1) In the case of type B, if the position as compression information in the output area is odd, dummy information is added to the output area (60).
2 to 603) Set to even position. In the case of type A, if the position as compression information in the output area is even, dummy information is added to the output area (604 to 605) and changed to an odd position.

FIG. 7 is a flowchart of the data output means (106).
The compressed records in the output area are output to a sequential file for output (701).

〔The invention's effect〕

As described above, according to the present invention, the user can perform compression without considering the data characteristics of the file by using both the compression means of the same character string before and after the sequential file and the compression means of the same continuous character. Can be performed, and further, there is an effect of improving the compression efficiency by using both compression means in combination.

[Brief description of the drawings]

1 is an overall configuration diagram of the present invention, FIG. 2 is a flowchart of data input means, FIG. 3 is a flowchart of record division means, FIG. 4 is a flowchart of the same character string compression means before and after, and FIG. FIG. 6 is a flowchart of the character adding means, FIG. 6 is a flowchart of the information adding means, and FIG. 7 is a flowchart of the data output means. 101 ... data input means, 102 ... record division means, 10
3 ... compressing means for the same character string before and after; 104 ... compressing means for the same continuous character; 105 ... adding means; 106 ... data outputting means.

Claims (1)

(57) [Claims] In a data compression processing method for a sequential file having continuous data of the same character or the same character string data as a previous record, data is taken out from the sequential file one record at a time and stored in a previously prepared work area. A comparison between the data input means to be performed and the record input immediately before indicates that the stored record has a portion of the type A field indicating that the stored record has the same character string data, and indicates that the stored record is other than the type A field. A record dividing means for dividing the data into a type B field portion and sequentially giving a compression instruction for each field; and activating when the field accompanying the compression instruction is type A, and compressing the type A field by a predetermined compression method. The same character string compression means before and after converting to information and outputting to an output area prepared in advance,
Activated when the field associated with the compression instruction is of type B, and when there is continuous data of the same character in the type B field, the continuous character portion is compressed information and compressed character by a predetermined compression method. To
The same continuous character compression means for converting the non-continuous character string into predetermined non-compressed information and an uncompressed character string and outputting the same to the output area;
When outputting an uncompressed character string to the output area, the compressed information of the same character string before and after is placed at an odd-numbered position in the compressed information in the output record, and the compressed information of the same character is successively Information adding means for adding dummy information predetermined so as to be located at an even-numbered position in the information; and sequentially storing the compressed records, which are activated at the end of the compression processing of the respective fields and output to the output area. A data compression processing method for a sequential file having data output means for outputting to a organized file.