JP3190855B2 - Decompression method of compressed data - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a restoration method for restoring compressed data to original data, and more particularly to a restoration method suitable for a portable information processing terminal.

[0002]

2. Description of the Related Art Conventionally, as a method of compressing / decompressing message data, message data is compressed by replacing a frequently occurring character string with a short code, and the code is used to restore the character string at the time of output such as display. Reverse substitution is performed on the original character string to expand the message data. In the conventional technology, a code after replacement and a character string corresponding to the replacement code included in the compressed data are both stored in a file, and the decompressed code is searched for in the file at the time of decompression, so that the corresponding character is obtained. The column is fetched and the original text of the message is restored.

[0003]

However, in the conventional method, when restoring data, a character string corresponding to the code is obtained by searching the replaced code in a file. There is a problem in that the search process takes a long time, and the restoration / display of the original text of the message is delayed.

In the conventional method, a code and an original text character string corresponding to the code are stored in a file, and a character string corresponding to the code is read at the time of restoration. Therefore, a memory buffer for file input / output is required at the time of restoration. Thus, there is a problem that the memory capacity usable for the program operation decreases accordingly.

Generally, in order to input / output file data, a memory buffer for data input / output is required. In many systems, when a program opens a file, the OS (basic software) automatically secures a memory buffer, so it is impossible for the program to read data from the file without using the memory buffer. . As a result, the memory capacity of the system is reduced by the amount of the buffer, which may hinder the program operation of the system in some cases. There was a problem that it became large.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a method of restoring compressed data which can restore data at high speed without requiring a system memory buffer.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a restoration method for restoring compressed data to original data by replacing data with a predetermined code. Wherein the code is a system
A continuous external character code not used for
Consecutive external character codes and corresponding text data
Is the original text storage data stored in order with the same data length.
Bull and, if the compressed data the external character codes is included, the relevant outside on the original text storing table
The storage position of the text data corresponding to the character code, the
The corresponding external character code and the head of the original text storage table
Between the external character code and the external character code and the text data
Bei means for calculating, based on the data length of the chromatography data, reads the text data from the calculated storage location of the original text storage table, and means for restoring the original data
It is characterized in that was example.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of a method for restoring compressed data according to the present invention. FIG. 1 shows an example in which the compressed data decompression method according to the present embodiment is applied to a portable information processing terminal system using an MS-DOS-based OS (basic software). In FIG. 1, a system message file 1 is a file provided outside the portable information processing terminal system, and is a file for storing original message data.

In the example of FIG. 1, the system message file 1 contains, for example, "... in that case, change the setting .... Press the return key .. Then, the setting can be changed." The message is stored. A data compression means (not shown) for compressing the original message data of the message file 1 is provided inside the portable information processing terminal system, and converts the message of the message file 1 into an external character code and compresses it. Then, the compressed message data is stored in the system message file 2.

In this embodiment, when data is compressed,
As the post-replacement code, a continuous external character code from 9900 (H) to 99FF (H) of an external character code which is not usually used in the system is used. For example, "Press the return key" is converted to 9900 (H), and "Change settings" is converted to 9901 (H) to compress the data. The data compression means uses this external character code to set the message of the system message file 1 to "... 9010 (H) in that case."
... 9900 (H). … Then you can do 9901 (H). "And stored in the system message file 2.

The original text storage table 3 is a table for storing external character codes and corresponding original text data. This original text storage table 3 contains the RO
The memory area is provided in an area where a memory image can be accessed. Here, in the present embodiment, although the external character code and the corresponding original text data are stored in the original text storage table 3, the text data is aligned to a fixed length data of 2 bytes of the external character code and 38 bytes of the original text data. Stored.

When the text data is shorter than a predetermined data length, a null code (a code indicating the end of character string data) is added to the text data so that the text data has the same data length. this is,
As will be described in detail later, by storing the text data in the original text storage table 3 with the same data length, the storage start position of each text data becomes an integer multiple from the head of the storage area in the original text storage table 3. In this way, the storage position of each text data is obtained by calculation.

Although the external character code and the corresponding text data are stored in the original text storage table 3 in FIG. 1, the external character code may not be provided. That is, if it is known in advance what text data is stored in the original text storage table 3, there is no need for an external character code, and only the text data may be stored with the same data length.

The original text restoration / display processing 4 reads out compressed data from the system message file 2, restores the original text before compression, and displays the message. Means for accessing the original text storage table 3 through the ROM area access area 6 of the memory area and acquiring the original text data corresponding to the external character code, and the output device 7 converts the message data passed from the original text restoration / display processing 4 Output means.

Next, a specific operation when displaying a system message according to the present embodiment will be described in detail with reference to the flowchart of FIG. In FIG. 2, first, original text restoration / display processing 4 reads compressed data from the system message file 2 (step 20).
1) It is determined whether or not the read data includes an external character code (9900 (H) to 99FF (H)) indicating replacement data (step 202).

In this case, as shown in FIG. 1, the system message file 2 contains "... in that case, perform 9901 (H) .... 9900 (H)."
(H) Yes. … ”Is stored. Therefore, in this case, the original text restoring / display processing 4 includes the external character codes 9900 (H), 9901
Since (H) is included, first, 9901 (H) is determined as an external character code indicating replacement data, and the external character code 9 is determined.
901 (H) is passed to the original text acquisition processing 5 to request acquisition of the original text data corresponding thereto (step 2).
03).

The original text acquisition processing 5 is executed through a ROM area access area 6 existing on the extended memory area.
The original text storage table 3 in the ROM area is accessed to obtain the original text data corresponding to the external character code. Specifically, in the original text storage table 3, each text data is stored in the order of the corresponding external character code,
Further, since each text data has the same data length by adding a NULL code, the storage position of the text data corresponding to the corresponding external character code is calculated by performing the following calculation (step 204).

The storage position (offset from the head of the storage area) of the text data can be obtained by the following equation.

Storage location of text data = (given external character code−
9900 (H)) × the length of one data of table 3 ...
(1) Here, assuming that the given external character code is 9901 (H), the length of one data in the original text storage table 3 = the external character code (2 bytes) + the text data (38 bytes) =
Since it is 40 bytes, the storage position of the text data is: storage position = (9901 (H) -9900 (H)) × 40
Byte = 40.

That is, it is found that the storage position of the text data corresponding to the external character code 9901 (H) is the second from the top of the original text storage table 3, and the original text acquisition processing 5 performs The text data “change setting” corresponding to the external character code 9901 (H) is read from the first (step 205), and passed to the original text restoration / display processing 4. In this case, if the length of the fixed-length data is 40 bytes, the storage position of the text data is an integral multiple of 40, and 0, 40, 80, 120
... Therefore, from this result, the storage location of the text data is the first data in the original text storage table 3,
It can be seen that the second data, the third data,...

The original text restoring / displaying process 4 performs another external character code 9900 included in the compressed data.
Similar processing is performed for (H), and the external character code 990 is obtained.
It requests the original text acquisition processing 5 to acquire text data corresponding to 0 (H). In this case as well, the original text acquisition processing 5 uses the external character code 9900 by using the expression (1).
Calculating the storage position of the text data corresponding to (H),
The text data at the corresponding storage position is read from the original text storage table 3 and passed to the original text restoration / display processing 5.

Here, since the storage position of the text data corresponding to the external character code 9900 (H) is 0, the original text acquisition processing 5 executes the first text data “return key” in the corresponding original text storage table 3. Please press "and pass it to original text restoration / display processing 4. The original text restoration / display processing 4 converts the external character code into the text data passed from the original text acquisition processing 5 and restores the message data before compression (step 2).
06). The original text restoration / display processing 4 outputs the restored message data to the output device 7 and displays the message on the output device 7 (step 207). If the message data does not include the external character code in step 202, the process proceeds to step 207, where the message data is displayed on the output device 7.

[0023]

According to the present invention as described above, according to the present invention, communication
The consecutive external character code and the corresponding text data are
Since the data is stored in the table in order with one data length, and when restoring the data, the storage position of the text data corresponding to the external character code is calculated, and the data is restored by reading out the text data from the obtained storage position. Instead of searching for a file as in the related art, no collation processing is required, so that the data restoration processing can be significantly speeded up as compared with the related art.

Further, since the original text data is stored not in a file but in a table accessible as a memory, a memory buffer for input / output is not required for reading out the text data, and the program for operating the program of the computer system is not required. Insufficient memory can be prevented. In particular, this is effective for a portable information processing terminal having a small memory capacity.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a compressed data decompression method according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 system message file (uncompressed data) 2 system message file (compressed data) 3 original text storage table 4 original text restoration / display processing 5 original text acquisition processing 6 ROM area access area 7 output device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03M 7/30

Claims (3)

(57) [Claims] 1. A decompression method for restoring compressed data to original data by replacing data with a predetermined code , said code being used by a system.
A continuous external character code that is not
The external character code and the corresponding text data are the same
An original text storage table stored in order by data length,
If it contains the external character codes to the compressed data, the storage location of the text data corresponding to the relevant external character code <br/> de on the original text storing table, the original text
The corresponding external character code and the first external character on the strike storage table
Code, and the external character code and text data
Means for calculating, based on the data length, reads the text data from the calculated storage location of the original text storing table, wherein this <br/> and and means for restoring the original data Decompression method for compressed data. 2. The compressed data according to claim 1, wherein in the original text storage table, by adding a predetermined code to the text data, each text data is made to have the same data length. Restoration method. 3. The method according to claim 1, wherein the original text storage table is provided in a ROM area accessible to a memory image.