JP2000138592A - Data expanding method, information processor, and computer readable recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data expanding method by which compressed data can be expanded in a state where the capacity to be secured on a RAM is smaller. SOLUTION: A data expanding method includes a reading-out and storing step in which compressed data 31 are stored in a predetermined compressed data storing area 32 in a RAM 22 by using compressed data composed of plural block data having a prescribed size as the data 31 and, at the same time, the data 31 are read out at every block data and an expanding step in which the block data are expanded whenever the block data are stored in the storing area 32 in the reading out and storing step and the expanded results are stored in a predetermined expanded data storing area 33 in the RAM 22, and at the same time, the execution of reading-out operations is instructed to the reading- out and storing step in order to prepare the expanded results of the compressed data stored in an auxiliary storage device 27 on the RAM 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a data decompression method for decompressing compressed data, an information processing apparatus using the data decompression method, and a program for operating a computer as such an information processing apparatus. The present invention relates to a computer-readable recording medium having recorded thereon.

[0002]

2. Description of the Related Art As is well known, various types of data are compressed in order to effectively use the storage capacity of an auxiliary storage device such as a hard disk drive or a CD-ROM drive. In particular, since graphic data is large-sized data, a program that makes extensive use of graphic data, for example, a program such as a game program, includes a routine for expanding (expanding) compressed data of graphic data. ing. When the graphic data becomes necessary, the compressed data is expanded by the routine.

[0003] Specifically, a conventional game program includes:
Data expansion is performed according to a procedure schematically shown in FIG. That is, when graphic data is needed, first, the CD-ROM drive 40
The total amount of the compressed data 41 of the graphic data stored in the CD-ROM set in the
The data is read to the compressed data storage area 43 prepared in advance. Next, decompression (decompression) processing is performed on the compressed data in the compressed data storage area 43, and the processing result is stored in the decompression data storage area 44 prepared in advance in the memory.
Is stored. Then, the graphic data stored in the decompressed data storage area 43 is
After some further processing, the VRA
M.

[0004]

As described above, in the conventional decompression procedure, both the compressed data and the decompressed data are stored in the RAM. For this reason, the conventional decompression procedure has a problem that the storage capacity that can be used for storing other information such as a program is limited.

[0005] The above problem will be specifically described below using a game machine as an example. Usually, a game machine is provided with a RAM having a storage capacity of about 2M (mega) bytes, and a game program uses a storage area of about 1M bytes in the RAM as a program area. And
For example, when displaying graphic data of 256 colors and 640 × 480 pixels, the size of the graphic data is about 300 kbytes. Therefore, a storage area for storing graphic data of 300 kbytes and compressed data are stored. 150k for temporary storage
The storage area for bytes (when the compression ratio is 50%) is RA
M.

That is, the storage area of 2 Mbytes in the RAM is used, for example, in the form shown in FIG. In the drawing, a system area is an area where an OS main body of a game machine is arranged, a system stack area is an OS work area, and a sound effect / sound data area is a sound effect set by a game program. Is an area in which data for generating is stored. In this figure, the size of the program area is set to about 1.2
M bytes.

The size of the storage area between the program area and the sound effect / sound data area shown in FIG. 4 is 640 kbytes.
This means that graphic data (600 kbytes) of 536 colors and 640 × 480 pixels can be stored. However, in this case, as shown in FIG. 5, no area (area of about 300 kbytes) capable of storing the compressed data of the graphic data remains in the RAM. Therefore, in order to display the graphic data, a part of other areas (the program area and the sound effect / sound data area) is opened for storing the compressed data, and after the expansion of the compressed data is completed, Processing such as returning the original data to the area used for storing the compressed data is required.

[0008] As described above, the conventional decompression procedure requires a large amount of storage capacity. Therefore, when the conventional decompression procedure is used, a program creation program is required to secure a storage area for compressed data. The degree of freedom was limited.

[0009] Further, compressed data is stored by adding an error check code, but conventionally, an error check code is added to the entire compressed data. For this reason, even if a read error occurs at the head of the compressed data, there is a problem that the reading is not detected unless the reading of the entire compressed data is completed. In other words, if the validity of the data is not verified by the error check code, the data is re-read, but in the conventional method, it takes time until the transfer of the valid data to the RAM by the re-read is completed. There was such a problem.

Therefore, an object of the present invention is to provide a memory (RA
M) It is an object of the present invention to provide a data decompression method, an information processing apparatus, and a computer-readable recording medium capable of decompressing compressed data in a state in which the capacity that must be secured on the compressed data is smaller.

Another object of the present invention is to provide a data decompression method, an information processing apparatus, and a program recording medium capable of decompressing compressed data to which an error check code has been added. An object of the present invention is to provide a data decompression method, an information processing device, and a computer-readable recording medium from which data can be acquired at high speed.

[0012]

In order to solve the above-mentioned problems, according to the present invention, in order to prepare a decompression result of compressed data stored in an auxiliary storage device in a memory, compressed data of a predetermined size is prepared as compressed data. A read storage step of reading compressed data for each block data and storing the read data in a predetermined compressed data storage area in the memory while using a block composed of a plurality of block data; Each time the block data is stored, the block data is decompressed, the decompression result is stored in a predetermined decompression data storage area in the memory, and a decompression step for instructing the read storage step to execute a read operation is performed. Including methods.

According to this data decompression method, the storage area that must be secured on the memory for data decompression is a compressed data storage area of the same size as the block data read in the read storage step. Therefore, according to the present method, as compared with the conventional decompression procedure, the storage capacity of the memory can be used for other purposes by increasing the size obtained by subtracting the size of the block data from the total size of the compressed data. Become. As a result, using this method, the memory can be used more freely, in other words, the program can be created more freely.

When the data decompression method of the present invention is carried out, each block data is divided into compressed block data, which is a component of the compressed data, and an error check code for verifying the validity of the compressed block data. The read storage step is performed by using a read step of reading compressed data for each block data, and an error check code included in the information read in the read step. A verification step of verifying the validity of the data, and, if the validity of the compressed block data is verified in the verification step, storing the compressed block data read in the reading step in a compressed data storage area of a memory. , Let the decompression step process the compressed block data, If the validity of Kkudeta is not verified, it can be assumed to include a read control step of causing the reading of the same information reading step.

According to this data decompression method, only data of a predetermined size is read out when an error occurs. Therefore, when a read error occurs, valid compressed data is obtained at a higher speed than before. become.

An information processing apparatus according to the present invention has an auxiliary storage device storing compressed data and a memory, wherein the compressed data comprises a plurality of block data of a predetermined size. Is read out for each block data and stored in a predetermined compressed data storage area in the memory, and each time the block data is stored in the compressed data storage area by the read storage means, the block data is read out. Decompressing, storing the decompression result in a predetermined decompression data storage area in the memory, and providing the readout storage means with decompression means for reading out the next block data.

That is, the information processing apparatus of the present invention is configured to execute the data decompression method of the present invention. Therefore, the information processing device of the present invention functions as a device that can use the memory more freely, in other words, a device that can more freely create a program.

When realizing the information processing apparatus of the present invention,
Each block data includes compressed block data which is a component of the compressed data, and an error check code for verifying the validity of the compressed block data. A verification unit that verifies the validity of the compressed block data included in the information using an error check code included in the information read by the reading unit; If the validity of the compressed block data is verified, the compressed block data read by the reading means is stored in the compressed data storage area of the memory, and the decompression means executes the processing, and the validity of the compressed block data is verified. If not, a read control for causing the read means to read the same information. It can be a means comprising a stage.

In the information processing apparatus configured as described above,
The data that is read again when an error occurs is only block data of a predetermined size. Therefore, this information processing device functions as a device that obtains valid compressed data at a higher speed than before when a reading error occurs.

In realizing the information processing apparatus of the present invention, an auxiliary storage device having a portable storage medium storing compressed data can be used.
In addition, it goes without saying that the information processing device of the present invention may be realized as a dedicated device, but a program for causing a computer (device having a CPU) to operate as the information processing device of the present invention is recorded. It may be realized using a recording medium that has been used.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a schematic configuration of an information processing apparatus according to an embodiment of the present invention. As illustrated, the information processing apparatus 20 of the embodiment includes a control unit 21, a RAM 22 having a storage capacity of 2 Mbytes, a sound processing unit 23, an input unit 24, an MDEC 25, a graphic processing unit 26,
This is a device having the D-ROM drive 27 as a main component, and is a device in which the recording medium 10 is inserted into the CD-ROM drive 27 and used.

The control unit 21 is a circuit including a CPU, a ROM, and the like.
Each part is controlled according to the program stored in the OM). The sound processing unit 23 is a circuit having a function of generating musical sounds, sound effects, and the like, and generates a sound corresponding to data read from the recording medium 10 and stored in the RAM 22 under the control of the control unit 21. The input unit 24 includes the information processing device 2
This is an interface for the user to input information for 0. Note that components other than the input unit 24 of the information processing device 20 are housed in one housing, and the input unit 24 is a device (a so-called controller) connected to the housing by a cable. .

The MDEC 25 has an inverse DCT (discrete cosi
ne transformation: A circuit that can execute the discrete cosine transform (JPEG) operation at high speed. JPEG (Joint Photographic E)
xperts Group) and MPEG (Moving Picture Expert Gr)
oup) or other data (CD-RO
It is used when decompressing (image data compressed and recorded in M). The graphic processing unit 26 is a circuit having a frame buffer, draws an image (polygon) in accordance with a command given from the control unit 21 on the frame buffer, and responds to image information stored in the frame buffer. Generate and output video signals. Also,
The graphic processing unit 26 also performs a process of outputting a video signal according to the expansion result of the MDEC 25. CD-ROM
The drive 27 is a CD-ROM reader.

The recording medium 10 (CD-ROM) set in the CD-ROM 27 stores a program including a data expansion routine for expanding the compressed data by the control unit 21 and compressed data of graphic data. Has become a medium. The compressed data of the graphic data recorded on the recording medium 10 includes a plurality of compressed data of a predetermined size including compressed block data forming a part of the compressed data and an error check code for verifying the validity of the compressed block data. Of the block data. In this embodiment, the block data is data of one sector (2 kbytes) of the recording medium 10.

The data decompression routine recorded in the recording medium 10 is a routine for causing the control unit 21 to decompress the compressed data according to the procedure schematically shown in FIG. That is, when operating in accordance with the data decompression routine (when graphic data is required), the control unit 21 first sets the CD-ROM drive 27
On the other hand, one block data constituting the compressed data 31 of the target graphic data (ie,
Command to read compressed block data and error check code). Then, it is determined whether or not the compressed block data is valid by using the read error check code. If the validity is not verified, the CD
-Instruct the ROM drive 27 to read the same compressed data.

When the validity of the read compressed block data is verified, the control unit 21 stores the compressed block data in a compressed data storage area 32 of the same size as the compressed block data secured in the RAM 22. At the same time, the compressed block data is expanded, and the expansion result is stored (added) in the expansion data storage area 33 secured in the RAM 22. The control unit 21 performs such processing,
By sequentially performing the processing on all the compressed block data constituting the compressed data, graphic data for one screen is prepared in the decompressed data storage area 33. Then, processing using the graphic data in the decompressed data storage area 33 is actually started.

The data decompression routine in the program recorded in the recording medium 10 is executed by the information processing device 20 (the control unit 2).
1) is operated in this way. That is, the data decompression procedure by the program recorded in the recording medium 10 requires only a compressed data storage area of the same size as the block data when decompressing the compressed data. Therefore, using this data decompression procedure, compared to the conventional decompression procedure, the storage capacity of the size obtained by subtracting the size of the block data from the total size of the compressed data can be used for other purposes. As a result, the memory can be used more freely, in other words, the program can be created more freely.

<Modifications> The technology used in the information processing apparatus of the embodiment can be used in various forms. For example, the block data may be data of two sectors or data of a smaller size instead of data of one sector. Further, the block data may be data that does not include the error check code.

[0030]

As described above, according to the data decompression method of the present invention, the memory can be used more freely, in other words, the program can be created more freely. Further, according to the information processing apparatus and the recording medium of the present invention, it is possible to realize an apparatus that can use a memory more freely, in other words, can create a program more freely.

Further, according to the data decompression method, the information processing apparatus, and the recording medium of the present invention in which the block data including the error check code is used, when the error occurs, the data to be reread is only the block data of a predetermined size. Therefore, when a read error occurs, legitimate compressed data is obtained at a higher speed than before.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an information processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an operation of the information processing apparatus according to the embodiment during a data decompression process.

FIG. 3 is a schematic diagram for explaining a data expansion procedure by a conventional game program.

FIG. 4 is a memory map for explaining a problem of a data decompression procedure using a conventional game program.

FIG. 5 is a memory map for explaining a problem of a data decompression procedure using a conventional game program.

[Explanation of symbols]

 Reference Signs List 10 recording medium (CD-ROM) 20 information processing device 21 control unit 22, 42 RAM 23 sound processing unit 24 input unit 25 MDEC 26 graphic processing unit 27, 40 CD-ROM drive 31, 41 compressed data 32, 43 compressed data storage Area 33, 44 Decompression data storage area

Claims (6)

[Claims] 1. A data decompression method for preparing a decompression result of compressed data stored in an auxiliary storage device on a memory, wherein the compressed data includes a plurality of block data of a predetermined size. A read storage step of reading data for each of the block data and storing the read data in a predetermined compressed data storage area in the memory; and in the read storage step, each time block data is stored in the compressed data storage area, A decompression step of decompressing the block data, storing the decompression result in a predetermined decompression data storage area in the memory, and instructing the read storage step to execute a read operation. Stretching method. 2. The reading and storing step, wherein each of the plurality of block data includes compressed block data that is a component of the compressed data, and an error check code for verifying the validity of the compressed block data. Using a reading step of reading the compressed data for each of the block data, and using an error check code included in the information read in the reading step to verify the validity of the compressed block data included in the information A verification step; and if the validity of the compressed block data is verified in the verification step, the compressed block data read in the reading step is stored in the compressed data storage area of the memory, and the decompression step is performed. To process the compressed block data. If the validity of has not been verified, the data decompression method according to claim 1, characterized in that it comprises a read control step of causing the reading of the same information in the reading step. 3. An information processing apparatus having an auxiliary storage device in which compressed data is stored and a memory, wherein the compressed data is composed of a plurality of block data of a predetermined size, Read-out means for reading out and storing in a predetermined compressed data storage area in the memory, each time block data is stored in the compressed data storage area by the read-out storage means, decompressing the block data; An information processing apparatus comprising: an expansion unit that stores the expansion result in a predetermined expansion data storage area in the memory; and the expansion unit that causes the read storage unit to read the next block data. 4. The read storage unit includes a plurality of block data, each of which includes compressed block data that is a component of the compressed data, and an error check code for verifying the validity of the compressed block data. Verifying the validity of the compressed block data included in the information using a reading unit that reads the compressed data for each block data, and an error check code included in the information read by the reading unit. Verification means; and if the validity of the compressed block data is verified by the verification means, the compressed block data read by the reading means is stored in the compressed data storage area of the memory, and the decompression means If the validity of the compressed block data is not verified, The information processing apparatus according to claim 3, characterized in that it comprises a read control means for causing the reading of the same information to the reading unit. 5. The information processing apparatus according to claim 3, wherein the auxiliary storage device includes a portable storage medium storing the compressed data. 6. A computer-readable recording medium on which a program for causing a computer to operate as the information processing apparatus according to claim 3 is recorded.