JPH03232016A - Method and device for data compression - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a data compression method and a data compression device when recording data in a data storage device.

(Prior Art) Conventionally, a run length method has been used as a method for compressing data in which there are few types of signals and long runs of the same symbol often appear. FIG. 3 shows a block flowchart of a conventional data compression device. In Figure 3, 51
is first data, 52 is a data compression device, 53 is data reading means, 54 is record comparing means, 55 is record counting means, 56 is data writing means, and 57 is second data.

FIG. 4 is a schematic diagram of data compressed by a conventional data compression method, where 41a is a first record, 41b is a second record, 42 is a sequence of identical records in the first data 51, and 43 is a code indicating the start of compression, 44 is the number of repetitions of the same record, and 45 is the sequence 4 of the same records.
This is the code in 2. 51 and 57 are first data and second data, respectively, which are the same as in FIG.

Next, the operation of the conventional example will be explained. First, the data reading means 53 reads the first data 51 in code units. Next, the record comparing means 54 compares the second record 41b with the immediately preceding first record 41a. The second record 41b is the first record 41a
If it is the same as , it is assumed that a sequence 42 of the same records has been detected, and the record counting means 55 counts the number of repetitions 44 of the same records. second record 4
1b is different from the first record 41a, it is assumed that the end of the sequence 42 of the same records has been detected, and the data writing means 56 writes the second data 57.

The number of repetitions 44 of the same record is returned to the initial value.

At this time, if the number of repetitions 44 of the same record is smaller than the predetermined number, the second data 57 is the same number of times as the number of repetitions 44 of the same record.

Write the first record 41a. If the number of repetitions 44 of the same record exceeds a predetermined number, the second
As data 57, a code 43 indicating the start of compression, the number of repetitions 44 of the same record, and the first record 41a are written.

Thereafter, data is compressed by repeating this process.

(Problem to be Solved by the Invention) However, in the conventional configuration described above, the sequence 42 of identical records is not detected in data where similar records are consecutive or where each record changes regularly. There was a problem that data could not be compressed.

The present invention solves the above conventional problems, and aims to provide a data compression device that can compress data that has similarities between records and regularity in the arrangement of records. .

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a data compression device equipped with means for dividing each record of data according to a predetermined rule.

(Function) Therefore, according to the present invention, the compression ratio can be increased because a portion with a high degree of redundancy is separated from each record of data and then compressed.

(Embodiment) FIG. 1 shows a block flowchart of a data compression apparatus in an embodiment of the present invention.

In FIG. 1, 11 is first data, 12 is a data compression device, 13 is data reading means, 14 is record dividing means, 15 is divided record comparing means, 16 is divided record counting means, 17 is data writing means, and 18 is second data.

FIG. 2 is a schematic diagram of data compressed by the real number data compression method in one embodiment of the present invention. In FIG. 2, 31 is real number data, 32 is an exponent part of the divided data, 32a is a first exponent part, 32b is a second exponent part,
33 is the compressed exponent part, 34 is the mantissa part of the divided data, 35 is the compressed mantissa part, 36 is a code indicating the start of compression, 37 is the number of repetitions of the same part, and 38 is the number of the same parts in the sequence A part of 39 is compressed real number data.

Next, the operation of the above embodiment will be explained.

1) First, the data reading means 13 reads the first real number data 31 in code units, and the data dividing means 1
4, each record is divided into an exponent part 32 and a mantissa part 33.

2) Next, by the divided record comparing means 15,
The exponent part 32b is compared with the exponent part 32a of the immediately preceding record.

3) If the second exponent part 32b is the same as the first exponent part 32a, it is assumed that a sequence of the same part has been detected, and the divided record counting means 16 counts the number of repetitions 37 of the same part. .

4) If the second exponent part 32b is different from the first exponent part 32a, it is assumed that the end of the sequence of the same part has been detected, and the data writing means 17 writes the compressed data 39, Return the number of repetitions 37 to the initial value. At this time, if the number of repetitions 37 of the same part is smaller than a predetermined number, the compressed data 39
The first part is repeated for the same number of times as 37 for the same part.
The exponent part 32a of is written. Number of repetitions of the same part 3
If 7 exceeds the predetermined number, the second data 3
9, a code 36 indicating the start of compression, the number of repetitions 37 of the same portion, and the first exponent part 32a are written.

5) Next, perform operations 2) to 4) above for the mantissa part.

By repeating steps 1) to 5), real number data is compressed.

As described above, according to this embodiment, by first dividing real number data into an exponent part and a mantissa part, the exponent part with a high degree of redundancy can be divided and this part can be significantly compressed.

In the above embodiment, the real number data is divided into an exponent part and a mantissa part, but instead of the real number data, it may be divided into the first half and the second half of a character code as character data.

(Effects of the Invention) The present invention has the excellent effect of increasing the redundancy of data that appears to have low redundancy and significantly compressing the data by providing a data division means.

[Brief explanation of drawings]

FIG. 1 is a block flowchart of a data compression device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of data compressed by a real data compression method according to an embodiment of the present invention, and FIG. 3 is a conventional data compression method. Block flowchart of the device, 1st ff! ! FIG. 2 is a schematic diagram of data compressed by a conventional data compression method. 11, 51... First data, 12.52... Data compression device [, 13, 53... Data reading means,
14... Record dividing means, 15... Divided record comparing means, 16... Divided record counting means, 17.56... Data writing means, 18.57
...Second data, 31...Real number data, 32...
・Exponent part of real number data, 32a...first exponent part, 3
2b... Second exponent part, 33... Compressed exponent part, 34... Mantissa part of real number data, 35... Compressed mantissa part, 36... Code indicating start of compression. 37...
Number of repetitions of the same part, 38...Part of the sequence of the same part, 39...Compressed real number data, 41a
...first record, 41b...second record,
42...Sequence of the same records, 44...Number of repetitions of the same records, 45...Rucode in the sequence of the same records, 54...Record comparison means. 55...Record counting means.

Claims (2)

[Claims] (1) First data is input, the first data is read into a data compression device, each record of the first data is divided according to a predetermined rule, and each part resulting from the division is A data compression method, comprising: comparing the numbers, calculating a count for each part of the record from the comparison, and writing second data based on the count. (2) means for inputting first data; means for reading said first data; means for dividing each record of said first data; and means for comparing portions of records of said first data. A data compression device comprising: a means for calculating a count of a record portion from the comparison; and a means for writing second data based on the count.