JP2016063475A - Encoding apparatus, encoding method, decoding apparatus, decoding method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoding apparatus and an encoding method for encoding data to be encoded to partially decodable data by using a method having high encoding efficiency, to provide a decoding apparatus and a decoding method for partially decoding the data encoded by using the method having high encoding efficiency, and to provide a program.SOLUTION: A conversion unit 107 converts respective characters included in data to be encoded into character identification numbers for identifying the characters. An encoding unit 108 encodes respective character identification numbers to binary data. A bit string identification number association unit 111 converts each bit string in which the data obtained by encoding the data to be encoded by the encoding unit 108 appear at high frequency into a bit string identification number. A reference flag-added encoding unit 114 encodes each bit string identification number to binary data.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an encoding device, an encoding method, a decoding device, a decoding method, and a program.

  In order to reduce the amount of data, an encoding method for encoding (compressing) data to be encoded and a decoding method for decoding the data to be decoded into original data before encoding are known.

  For example, Non-Patent Document 1 indicates the position in the data of the character string that appears first and the length of the character string for the character string that appears the second time or later for the character string that repeatedly appears in the data to be encoded. An LZ encoding method for encoding data to be encoded by converting it into data (hereinafter referred to as frequent character string metadata) is disclosed. Non-Patent Document 1 discloses a character string that repeatedly appears in the original data before encoding each of a plurality of frequent character string metadata included in the data to be decoded (data encoded by the LZ encoding method). The decoding method which decodes the data of decoding object by replacing with the character string which appears first among these is disclosed.

Daisuke Okanohara "World of High-Speed String Analysis", Iwanami Publishing, 2012

  However, in the conventional encoding method / decoding method, when data that requires partial decoding is targeted for encoding / decoding, the encoding efficiency is low. For example, decoding of dictionary data requires decoding in units of headwords that the user has searched for. If a conventional encoding method / decoding method tries to realize such partial decoding, the dictionary Data must be encoded in headword units. This will be specifically described by taking the above-described LZ encoding method as an example. When the entire dictionary data is encoded by the LZ encoding method, the above-mentioned frequent characters are included in a part of the encoded dictionary data. There is a high possibility that the first character string that appears repeatedly in the original data before encoding, which is necessary for the replacement of the column metadata, is not included. Therefore, when the entire dictionary data is encoded by the LZ encoding method, partial decoding of the dictionary data is almost impossible. Accordingly, decoding of dictionary data in units of headwords requires encoding in units of headwords. For the same reason as for other encoding methods and decoding methods, partial decoding of the original data before encoding is necessary for partial decoding of the data to be decoded. Such partial encoding significantly reduces the encoding efficiency.

  The present invention is to solve the above-described problems, and an encoding apparatus and encoding that encode data to be encoded into partially decodable data using a method with high encoding efficiency It is an object to provide a decoding apparatus, a decoding method, and a program for partially decoding data encoded using a method, a method with high encoding efficiency.

In order to achieve the above object, an encoding apparatus according to the first aspect of the present invention provides:
A character identification number storage unit that stores a character included in data to be encoded and a character identification number for identifying the character in association with each other;
A conversion unit that refers to the character identification number storage unit and converts a character included in the data to be encoded into a character identification number associated with the character;
An encoding unit that encodes the character identification number converted by the conversion unit into binary data;
A bit string identification number associating unit that associates a bit string identification number that identifies the bit string and stores it in the bit string identification number storage unit for each identical bit string that appears in the binary data of the character identification number encoded by the encoding unit;
A bit string identification number converter that converts the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Encoding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted by the bit string identification number conversion unit, and encoding the bit string identification number into binary data And
Is provided.

In order to achieve the above object, a decoding device according to the second aspect of the present invention provides:
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number A compressed data storage unit for storing compressed data,
A character identification number storage unit for storing the character included in the data to be encoded and the character identification number for identifying the character in association with each other;
A bit string identification number storage unit that associates and stores the bit string identification number for identifying the bit string for each identical bit string that appears in the binary data of each character identification number;
An input unit for inputting a condition for specifying data to be decrypted;
Among the compressed data stored in the compressed data storage unit, the data satisfying the condition is specified as the data to be decoded, and the binary data of the character identification number and the binary data of the bit string identification number constituting the specified decoding target data A bit string identification number decoding unit for decoding binary data of the bit string identification number into the bit string identification number,
A bit string identification number converting unit that converts the bit string identification number decoded by the bit string identification number decoding unit into a bit string associated with the bit string identification number with reference to the bit string identification number storage unit;
A decoding unit that decodes the binary data of the character identification number constituting the data to be decoded and the bit string converted by the bit string identification number conversion unit into the character identification number;
A conversion unit that refers to the character identification number storage unit and converts the character identification number decoded by the decoding unit into a character associated with the character identification number;
Is provided.

  According to the present invention, data to be encoded can be encoded into partially decodable data using a method with high encoding efficiency. In addition, data encoded using a method with high encoding efficiency can be partially decoded.

It is a figure which shows the physical structure of the encoding apparatus which concerns on embodiment of this invention. It is a figure which shows the function structure of the encoding apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of the encoding process which concerns on embodiment of this invention. It is a figure which shows dictionary data (data of encoding object). It is a figure which shows the appearance frequency in the dictionary data of each character. It is a figure which shows correlation with a character and a character identification number. It is a figure which shows the binary data before final encoding. It is a figure which shows the appearance frequency in the binary data before the last encoding of each bit sequence. It is a figure which shows correlation with a bit string and a bit string identification number. It is a figure which shows the physical structure of the decoding apparatus which concerns on embodiment of this invention. It is a figure which shows the function structure of the decoding apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of the decoding process which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  According to the conventional encoding / decoding method, when data is to be partially decoded, the original data before encoding must be partially encoded. Therefore, it takes time for encoding, and the encoding efficiency is low. In this regard, the encoding device 100 and the decoding device 200 according to the present invention enable partial decoding even if the original data before encoding is collectively encoded. Hereinafter, the physical configuration and functional configuration of such an encoding apparatus 100 and decoding apparatus 200 will be described.

  The encoding device 100 according to the present embodiment is physically configured as shown in FIG. That is, the encoding device 100 includes a ROM (Read Only Memory) 10, a RAM (Random Access Memory) 11, an external storage device 12, an input device 13, a display device 14, and a CPU (Central Processing Unit) 15. .

  The ROM 10 stores an initial program for performing various initial settings, hardware inspection, program loading, and the like. The RAM 11 temporarily stores various software programs executed by the CPU 15 and data necessary for executing these software programs.

  The external storage device 12 is a hard disk, for example, and stores various software programs, data, and the like. These software programs include application software programs, basic software programs such as OS (Operating System), and the like.

  The input device 13 includes a keyboard, a mouse, a track pad, and the like, and receives input from the user. The input device 13 generates a signal based on input from a keyboard, mouse, track pad, etc., and supplies the signal to the CPU 15.

  The display device 14 includes a screen such as a liquid crystal display and displays text data and image data supplied from the CPU 15.

  The CPU 15 reads the software program stored in the external storage device 12 into the RAM 11 and controls the execution of the software program, thereby realizing the following functional configuration.

  The encoding device 100 is functionally configured as shown in FIG. That is, the encoding apparatus 100 includes an encoding candidate data storage unit 101, a display unit 102, an input unit 103, a character appearance frequency acquisition unit 104, a character identification number association unit 105, and a character identification number storage unit 106. A conversion unit 107, an encoding unit 108, a start position storage unit 109, a bit string appearance frequency acquisition unit 110, a bit string identification number association unit 111, a bit string identification number storage unit 112, and a bit string identification number conversion unit 113, an encoding unit with a reference flag 114, an encoding unit with a non-reference flag 115, and a compressed data storage unit. The encoding candidate data storage unit 101, the character identification number storage unit 106, the start position storage unit 109, the bit string identification number storage unit 112, and the compressed data storage unit 116 are constructed in the external storage device 12 shown in FIG. Has been.

  The encoding candidate data storage unit 101 stores a plurality of encoding candidate data. The encoding candidate data is text data such as dictionary data.

  The display unit 102 displays the name (file name) of the file in which the encoding candidate data is recorded on the display device 14. The user refers to the file name displayed on the display device 14 and designates which of the encoding candidate data is to be encoded.

  The input unit 103 receives a signal generated by the input device 13. This signal indicates a file name designated by the user via the input device 13. The input unit 103 specifies data to be encoded based on the signal received from the input device 13. Then, an instruction to encode the data to be encoded is input to the character appearance frequency acquisition unit 104.

  Based on the instruction input from the input unit 103, the character appearance frequency acquisition unit 104 acquires encoding target data from the encoding candidate data stored in the encoding candidate data storage unit 101.

The character appearance frequency acquisition unit 104 acquires the appearance frequency in the encoding target data for each character included in the encoding target data. For example, when the data to be encoded is the dictionary data 1 shown in FIG. 4, the appearance frequency of each character in the dictionary data 1 is as shown in FIG.
The appearance frequency is acquired for all characters included in the data to be encoded.

  The character identification number associating unit 105 associates and stores the character identification number for identifying the character in the character identification number storage unit 106 for each character included in the data to be encoded. At this time, the character identification number associating unit 105 associates character identification numbers having smaller values in order from the character having the highest appearance frequency in the data to be encoded. For example, if the data to be encoded is the dictionary data 1 shown in FIG. 4, as shown in FIG. 6, the characters “t”, “h”, The character identification numbers 0, 1, 2,... Are associated with “e”.

Hereinafter, the reason for associating a character identification number with a character based on the appearance frequency and the reason for associating a character identification number with a small value with a character having a high appearance frequency will be described.
In text compression, the character code system may cause a reduction in compression rate. In particular, when UTF-8 is employed, multilingual text is targeted for compression, so that depending on the language, the code length becomes redundant and the compression rate decreases. Therefore, the present invention does not encode a character into a character code, but associates a character identification number with the character and encodes the character into binary data of the character identification number. Thus, the compression rate is not affected by the character code system. In addition, if frequent characters are encoded into binary data having a long code length, the size of the compressed data increases, so the present invention is devised to prevent this from happening. Specifically, as described above, a character identification number having a small value is associated with a frequently appearing character. Then, by using encoding methods that can encode binary data with a shorter code length as the value is smaller, such as delta encoding method, variable byte code encoding method, and Huffman encoding method, frequent characters are converted into binary data with a shorter code length. Encode. As a result, the size of the compressed data is significantly reduced as compared with the case of encoding into a character code.

  As shown in FIG. 6, the character identification number storage unit 106 stores the character included in the encoding target data and the character identification number in association with each other.

  The conversion unit 107 refers to the character identification number storage unit 106 and converts the character included in the data to be encoded into a character identification number associated with the character.

  The encoding unit 108 encodes the character identification number converted by the conversion unit 107 into binary data. In this specification, binary data encoded by the encoding unit 108 is referred to as final pre-encoding binary data. FIG. 7 shows binary data 2 before final encoding when the dictionary data 1 shown in FIG. 4 is encoded by the conversion unit 107. The binary data 2 before final encoding is actually a set of bits representing 0 or 1. However, it should be noted that for convenience of explanation, hexadecimal notation is used every 8 bits. For example, in the bit string “12A5B8CA” shown in FIG. 7, “00010010”, “10100101”, “10111000”, “11001010” are hexadecimal numbers such as “12”, “A5”, “B8”, “CA”, respectively. It is written

  The start position storage unit 109 stores a start position of a headword included in the data to be encoded (also referred to as a compression boundary in the present specification, which indicates a position serving as a start point when decoding compressed data).

The bit string appearance frequency acquisition unit 110 acquires the appearance frequency in the binary data before final encoding for each identical bit string included in the binary data before final encoding. For example, in the binary data 2 before final encoding shown in FIG. 7, the appearance frequency of each bit string is as shown in FIG. However, the number of appearances of the bit string straddling the compression boundary described above is not included in the appearance frequency of the bit string.
Although the number of digits of the bit string depends on the encoding method, about 32 digits are appropriate for a natural language. Therefore, in this embodiment, the number of digits of the bit string is 32 digits. However, the number of digits of the bit string is not limited to 32 digits, and may be any number of digits.

  The bit string identification number associating unit 111 stores the bit string identification number for identifying the bit string in the bit string identification number storage unit 112 for each identical bit string that appears in the pre-encoded binary data. At this time, the bit string identification number associating unit 111 associates the bit string identification number with the bit string having the first to fifth highest appearance frequency. In addition, bit string identification numbers having smaller values are associated in descending order of bit strings. For example, in the case of binary data 2 before final encoding shown in FIG. 7, as shown in FIG. 9, the bit string “12A5B8CA”, the bit string “12A5B8CA” having the highest appearance frequency is the first, second, third, fourth, and fifth. Bit string identification numbers 0, 1, 2, 3, and 4 are associated with DF43A68C, bit string "385C65F9", bit string "935AD6CD", and bit string "B58CEEA5", respectively.

  As shown in FIG. 9, the bit string identification number storage unit 112 stores a bit string identification number for identifying a bit string in association with each bit string that appears in the binary data before final encoding.

  The bit string identification number conversion unit 113 refers to the bit string identification number storage unit 112 and converts the same bit string appearing in the binary data before final encoding into a bit string identification number associated with the bit string. However, the bit string identification number conversion unit 113 does not convert the bit string into the bit string identification number when the bit string crosses the compression boundary described above. Thereby, data (compressed data) encoded so as to be decodable in units of headwords can be generated.

The encoding unit with a reference flag 114 encodes the bit string identification number converted by the bit string identification number conversion unit 113 into binary data using an encoding method such as a delta encoding method, a variable byte code encoding method, or a Huffman encoding method. Turn into. Then, a reference flag (a flag indicating that the bit string identification number storage unit 112 is referred to at the time of decoding) is associated with the binary data of the bit string identification number.
In this way, by encoding a frequently occurring bit string into binary data having a bit string identification number with a short code length, the size of the encoded data (compressed data) can be reduced.

The non-reference flag-attached encoding unit 115 performs the process from the beginning of the bit string to the appearance of the bit string associated with the bit string identification number for the bit string that is not associated with the bit string identification number among the bit strings that appear in the binary data before final encoding. Encode the number of bits into binary data. At this time, a non-reference flag (a flag indicating that the bit string identification number storage unit 112 is not referred to at the time of decoding) is associated with binary data having the number of bits.
If the bit string crosses the compression boundary, the number of bits from the beginning of the bit string to the compression boundary is encoded into binary data, and the non-reference flag is associated with the binary data.
Further, the same processing is performed on the bit string that is not converted to the bit string identification number because it crosses the compression boundary among the bit strings associated with the bit string identification number, depending on whether or not the compression boundary is crossed.

  The compressed data storage unit 116 stores binary data (compressed data) obtained by encoding data to be encoded.

  The flow of the encoding process performed by the encoding apparatus 100 as described above will be described with reference to the flowchart shown in FIG.

[Encoding process]
It is assumed that the display unit 102 displays the name (file name) of the file in which the encoding candidate data is recorded on the display device 14. The user refers to the file name displayed on the display device 14 and inputs the file name of an encoding target among these encoding candidates to the input device 13. The input device 13 generates a signal indicating the input file name and supplies it to the input unit 103. The input unit 103 receives a signal supplied from the input device 13 and specifies a file to be encoded by the user. Then, the user supplies an instruction to the character appearance frequency acquisition unit 104 to encode the file data to be encoded. The character appearance frequency acquisition unit 104 receives this instruction and starts the encoding process shown in FIG.

  First, the character appearance frequency acquisition unit 104 acquires data to be encoded from among a plurality of encoding candidate data stored in the encoding candidate data storage unit 101 based on the instruction (step S10). Hereinafter, in order to facilitate understanding, it is assumed that dictionary data 1 shown in FIG. 4 is acquired as data to be encoded.

  The character appearance frequency acquisition unit 104 acquires the appearance frequency in the dictionary data 1 for each character included in the dictionary data 1 (step S11). As shown in FIG. 5, the appearance frequency of the character “t” in the dictionary data 1 is highest at 92041 times. Subsequently, the appearance frequency of the character “h”, the character “e”, the character “s”, the character “r”,... Is second, third, with 83890, 80984, 76189, 68607,. 4th, 5th ... high.

  The character identification number associating unit 105 associates character identification numbers with smaller values in order from the character having the highest appearance frequency in the dictionary data 1 and stores them in the character identification number storage unit 106 (step S12). Specifically, as shown in FIG. 6, the character “t”, the character “h”, the character “e”, the character whose appearance frequency is the first, second, third, fourth, fifth,... The character identification numbers 0, 1, 2, 3, 4... Are associated with “s”, the character “r”.

  The conversion unit 107 refers to the character identification number storage unit 106 and converts the characters included in the dictionary data 1 into character identification numbers associated with the characters (step S13). Specifically, the character “t”, the character “h”, the character “e”,... Included in the dictionary data 1 are converted into character identification numbers 0, 1, 2,.

  The encoding unit 108 encodes the character identification number converted by the conversion unit 107 into binary data (step S14). Specifically, dictionary data 1 is encoded into binary data 2 before final encoding shown in FIG. Note that, as described above, for convenience of explanation, the binary data 2 before final encoding shown in FIG. 7 is represented by a plurality of numerical values in hexadecimal notation. Actually, the binary data 2 before final encoding is a set of bits representing 0 or 1.

The bit string appearance frequency acquisition unit 110 acquires the appearance frequency in the binary data 2 before final encoding for each identical bit string that appears in the binary data 2 before final encoding (step S15). However, the number of appearances of the bit string straddling the start position (compression boundary) of the headword included in the dictionary data 1 is not included in the appearance frequency of the bit string.
As shown in FIG. 8, in the binary data 2 before final encoding, the appearance frequency of the bit string “12A5B8CA” is the highest at 150 times. Also, the appearance frequency of the bit string “DF43A68C”, the bit string “385C65F9”, the bit string “935AD6CD”, the bit string “D58CEEA5”, the bit string “1B3C2A09”,... 130 times, 100 times, 80 times, 70 times, 40 times, respectively.・ In 2nd, 3rd, 4th, 5th, 6th and so on.

  The bit string identification number associating unit 111 associates bit string identification numbers with smaller values in order from the bit string with the highest appearance frequency to the bit string with the first to fifth highest occurrence frequency, and stores them in the bit string identification number storage unit 112 ( Step S16). Specifically, as shown in FIG. 9, the bit string “12A5B8CA”, the bit string “DF43A68C”, the bit string “385C65F9”, the bit string “935AD6CD” having the first, second, third, fourth, and fifth highest appearance frequencies. , Bit string identification numbers 0, 1, 2, 3, 4 are associated with the bit string “B58CEEA5”, respectively.

  The bit string identification number conversion unit 113 refers to the bit string identification number storage unit 112 and converts the same bit string appearing in the binary data 2 before final encoding into a bit string identification number associated with the bit string (step S17). Specifically, the bit string “12A5B8CA”, the bit string “DF43A68C”, the bit string “385C65F9”,... Are converted into bit string identification numbers 0, 1, 2,. However, the bit string identification number conversion unit 113 does not convert a bit string straddling the compression boundary into a bit string identification number.

  The encoding unit with reference flag 114 encodes the bit string identification number converted by the bit string identification number conversion unit 113 into binary data. Then, a reference flag (a flag indicating that the bit string identification number storage unit 112 is referred to at the time of decoding) is associated with the binary data of the bit string identification number (step S18).

Next, the non-reference flag-attached encoding unit 115 generates a bit string associated with a bit string identification number from the beginning of the bit string for a bit string that is not associated with a bit string identification number among the bit strings that appear in the binary data 2 before final encoding. Encode the number of bits before appearing to binary data. At this time, a non-reference flag (a flag indicating that the bit string identification number storage unit 112 is not referred to at the time of decoding) is associated with binary data having the number of bits. If the bit string crosses the compression boundary, the number of bits from the beginning of the bit string to the compression boundary is encoded into binary data, and the non-reference flag is associated with the binary data. (Step S19).
Furthermore, the encoding unit 115 with a non-reference flag also includes a case where a bit string that has not been converted to a bit string identification number because it crosses a compression boundary among bit strings associated with a bit string identification number and a case where the bit string does not cross the compression boundary. Accordingly, the same processing is performed (step S20).

  Then, the encoding unit 115 with the non-reference flag stores the binary data (compressed data) obtained by encoding the dictionary data 1 by the processing from steps S10 to S20 in the compressed data storage unit 116 (step S21).

  Next, the physical configuration and functional configuration of the decoding apparatus 200 that partially decodes the compressed data encoded by the above encoding process will be described.

  The decoding device 200 according to the present embodiment is physically configured as shown in FIG. That is, the decoding device 200 includes a ROM 20, a RAM 21, an external storage device 22, an input device 23, a display device 24, and a CPU 25.

  The ROM 20 stores an initial program for performing various initial settings, hardware inspection, program loading, and the like. The RAM 21 temporarily stores various software programs executed by the CPU 25, data necessary for executing these software programs, and the like.

  The external storage device 22 is a hard disk, for example, and stores various software programs, data, and the like. These software programs include application software programs, basic software programs such as an OS, and the like.

  The input device 23 includes a keyboard, a mouse, a track pad, and the like, and receives input from the user. The input device 23 generates a signal based on input from a keyboard, mouse, track pad, etc., and supplies the signal to the CPU 25.

  The display device 24 includes a screen such as a liquid crystal display, and displays text data and image data supplied from the CPU 25 on the screen.

  The CPU 25 implements the following functional configuration by reading the software program stored in the external storage device 22 into the RAM 21 and executing and controlling the software program.

  The decoding device 200 is functionally configured as shown in FIG. That is, the decoding device 200 includes a bit string identification number storage unit 201, a compressed data storage unit 202, a start position storage unit 203, a bit string identification number decoding method storage unit 204, an input unit 205, and a bit string identification number decoding unit 206. A bit string identification number conversion unit 207, a character string identification number decoding method storage unit 208, a character identification number storage unit 209, a decoding unit 210, a conversion unit 211, and a display unit 212. The bit string identification number storage unit 201, the compressed data storage unit 202, the start position storage unit 203, and the character identification number storage unit 209 are respectively a bit string identification number storage unit 112, a compressed data storage unit 116, and a start included in the encoding device 100. The same data as the data stored in the position storage unit 109 and the character identification number storage unit 106 is stored. A bit string identification number storage unit 201, a compressed data storage unit 202, a start position storage unit 203, a bit string identification number decoding method storage unit 204, a character identification number decoding method storage unit 208, a character identification number storage unit 209, Is constructed in the external storage device 22 shown in FIG.

  The bit string identification number storage unit 201 stores a bit string identification number for identifying a bit string in association with each bit string that appears in the binary data before final encoding.

  The compressed data storage unit 202 stores binary data (compressed data) in which data to be encoded is encoded by the encoding process.

  The start position storage unit 203 stores the start position (compression boundary) of the headword included in the data to be encoded.

  The bit string identification number decoding method storage unit 204 stores a method for decoding binary data of a bit string identification number included in the compressed data into a bit string identification number. As a specific example, when the binary data of the bit string identification number is encoded using the delta encoding method, the bit string identification number decoding method storage unit 204 stores the binary data encoded by the delta encoding method. Is stored as a bit string identification number decoding method.

  The input unit 205 receives a signal generated by the input device 23. This signal indicates a headword specified by the user via the input device 23. The input unit 205 sets a headword designated by the user and an example sentence of the headword as a condition for specifying data to be decoded. Then, the condition set in the bit string identification number decoding unit 206 is input.

  The bit string identification number decoding unit 206 specifies data among the compressed data that satisfies the condition input from the input unit 205 as data to be decoded. For example, if the condition is the headword “the” and its example sentence, the headword “the” and its example sentence included in the compressed data are specified as data to be decoded. Note that the positions of headwords and example sentences in the compressed data are specified based on the start positions of the headwords stored in the start position storage unit 203.

Also, the bit string identification number decoding unit 206 determines whether a reference flag or a non-reference flag exists at the start position of the headword. When it is determined that the reference flag exists, the binary data of the bit string identification number associated with the reference flag is decoded into the bit string identification number. As a decoding method, a decoding method stored in the bit string identification number decoding method storage unit 204 is employed.
On the other hand, when it is determined that the non-reference flag exists, the control of the decoding process is transferred to the decoding unit 210.

  The bit string identification number conversion unit 207 refers to the bit string identification number storage unit 201 and converts the bit string identification number decoded by the bit string identification number decoding unit 206 into a bit string associated with the bit string identification number. Then, the converted bit string is copied to the queue.

  The character identification number decoding method storage unit 208 stores a method for decoding character identification number binary data included in the compressed data into character identification numbers. As a specific example, when the binary data of the character identification number is encoded using the delta encoding method, the character identification number decoding method storage unit 208 stores the binary data encoded by the delta encoding method. Is stored as a character string identification number decoding method.

  The character identification number storage unit 209 stores a character included in the compressed data and a character identification number for identifying the character in association with each other.

The decoding unit 210 decodes the bit string copied to the queue by the bit string identification number conversion unit 207 into a character identification number.
On the other hand, when the decoding process is transferred from the bit string identification number decoding unit 206, the decoding unit 210 reads data indicating the number of digits of the bit associated with the non-reference flag. Then, the binary data corresponding to the number of digits is further read and copied to the queue. Then, the binary data copied to the queue is decoded into a character identification number.
Note that the decoding method stored in the character identification number decoding method storage unit 208 is employed.

  The conversion unit 211 refers to the character identification number storage unit 209 and converts the character identification number decoded by the decoding unit 210 into a character.

  The display unit 212 displays data obtained by decoding the compressed data (original data before encoding) on the display device 24.

  The flow of the decoding process executed by the decoding apparatus 200 as described above will be described with reference to the flowchart shown in FIG.

[Decryption process]
Here, it is assumed that the compressed data stored in the compressed data storage unit 202 is binary data of the dictionary data 1 shown in FIG. Then, it is assumed that the user inputs the headword “the” to the input device 23 in order to examine the definition of “the” and usage examples of “the”. In this case, the input device 23 generates a signal indicating the input headword “the” and supplies the signal to the input unit 205. The input unit 205 receives the signal supplied from the input device 23 and specifies that the input headword is “the”. Then, the headword “the” and its example sentence are set as a condition to be decoded, and the condition set in the bit string identification number decoding unit 206 is input. The bit string identification number decoding unit 206 receives the above condition from the input unit 205 and starts the decoding process shown in FIG.

  The bit string identification number decoding unit 206 identifies data among the compressed data that satisfies the above conditions as data to be decoded (step S30). Here, the headword “the” and its example sentences satisfy the above conditions. Therefore, the headword “the” and its example sentence are specified as data to be decoded.

  Next, the bit string identification number decoding unit 206 determines whether a reference flag or a non-reference flag exists at the start position of the headword “the” (step S31). If it is determined that the reference flag exists, the binary data of the bit string identification number associated with the reference flag is read. Then, using the decoding method stored in the bit string identification number decoding method storage unit 204, the binary data of the bit string identification number is decoded into the bit string identification number (step S32). Here, the bit string identification number decoded in step S32 is “0”.

  The bit string identification number conversion unit 207 refers to the bit string identification number storage unit 201 and converts the bit string identification number decoded by the bit string identification number decoding unit 206 into a bit string associated with the bit string identification number (step S33). Then, the converted bit string is copied to the queue (step S34). Specifically, the bit string identification number “0” decoded in step S32 is converted into the bit string “12A5B8CA” (see FIG. 9) associated with the bit string identification number “0”, and the bit string “12A5B8CA” is copied to the queue. To do.

  The decoding unit 210 decodes the bit string existing in the queue into the character identification number using the decoding method stored in the character identification number decoding method storage unit 208 (step S35). Here, it is assumed that the bit string “12A5B8CA” is decoded into character identification numbers “0”, “1”, “2”, and “3”.

  The conversion unit 211 refers to the character identification number storage unit 209 and converts the character identification number decoded by the decoding unit 210 into a character (step S36). Specifically, the character identification numbers “0”, “1”, “2”, “3” decrypted in step S35 are replaced with the characters “t”, “h”, “ e ”and“ s ”(see FIG. 6).

  When the conversion to characters is completed, the conversion unit 211 determines whether all the data to be decoded has been converted to characters (step S37).

  When the conversion unit 211 determines that there is a portion that has not been converted into the data to be decoded (step S37; No), the conversion unit 211 moves the control of the decoding process to the bit string identification number decoding unit 206. In this case, the bit string identification number decoding unit 206 determines whether a reference flag or a non-reference flag exists at the end of the binary data of the bit string identification number that has been decoded (step S31). If the bit string identification number decoding unit 206 determines that a non-reference flag exists, the bit string identification number decoding unit 206 moves the control of the decoding process to the decoding unit 210. In this case, the decoding unit 210 reads binary data having the number of bits associated with the non-reference flag (step S38). Then, the binary data corresponding to the number of digits is read from the tail of the binary data of the bit string identification number that has been decoded (step S39) and copied to the queue (step S40).

  The decoding unit 210 decodes the binary data present in the queue into a character identification number using the decoding method stored in the character identification number decoding method storage unit 208 (step S35).

  The conversion unit 211 refers to the character identification number storage unit 209 and converts the character identification number decoded by the decoding unit 210 into a character (step S36).

  When the conversion to characters is completed, the conversion unit 211 determines whether all the data to be decoded has been converted to characters (step S37). When it is determined that there is a part that has not been converted into the data to be decoded (step S37; No), the control of the decoding process is transferred to the bit string identification number decoding unit 206. Then, the processing from steps S31 to S37 is repeatedly executed until all data to be decoded is converted into characters.

  If it is determined in step S37 that the conversion unit 211 has converted all data to be decoded into characters (step S37; Yes), the display unit 212 displays the converted characters on the display device 24 (step S41). . Specifically, the headword “the” and its example sentence are displayed on the display device 24.

Thus, in the decoding process, a part of the compressed data is sequentially decoded from the start position of the headword designated by the user. At this time, it is determined before decoding whether a reference flag or a non-reference flag exists, and it is specified whether the binary data to be decoded is binary data of a character identification number or binary data of a bit string identification number. Here, when it is determined that the reference flag exists, it is specified as binary data of the bit string identification number, and when it is determined that the non-reference flag exists, it is specified as binary data of the character identification number. . Then, the binary data of the character identification number is decoded into the character identification number and the binary data of the bit string identification number is decoded into the bit string by a decoding method corresponding to the type of the specified binary data.
What should be noted here is that the original data before conversion necessary for converting the character identification number into characters and the original data before conversion necessary for converting the bit string into the character identification number are stored in the character identification number. It can be freely acquired from the unit 209 and the bit string identification number storage unit 201. This means that the data to be decoded, which is a part of the compressed data, can be converted into the original data even if the original data before conversion does not exist. Therefore, with the conventional encoding method / decoding method, partial decoding cannot be performed unless the data to be encoded is partially encoded in advance. Even partial decoding can be performed.

  As described above, the encoding apparatus 100 according to the present embodiment encodes data to be encoded into binary data of a character string identification number and a bit string identification number. Then, the decoding device 200 refers to the character identification number storage unit 209 and the bit string identification number storage unit 201, and partially decodes the binary data (compressed data) encoded by the encoding device 100. As described above, these allow partial decoding of compressed data without partial encoding of data to be encoded. Therefore, compared with the conventional encoding method / decoding method, encoding is not time-consuming and encoding efficiency is high.

(Modification)
Although the embodiment of the present invention has been described above, the above embodiment is an example, and the scope of application of the present invention is not limited to this. That is, the embodiments of the present invention can be applied in various ways, and all the embodiments are included in the scope of the present invention.

  For example, in the above embodiment, the bit string identification number is associated with the bit string having the first to fifth highest occurrence frequency, but the target to associate the bit string identification number is not limited to the bit string having the first to fifth highest occurrence frequency. Absent. For example, a bit string identification number may be associated with a bit string having the highest appearance frequency from 1 to 10, or a bit string identification number may be associated with all bit strings. However, since a compression rate is lowered when a bit string having a low appearance frequency is encoded into binary data having a bit string identification number having a long code length, it is preferable to limit a target to be associated with a bit string identification number to a bit string having a high appearance frequency.

  In the above embodiment, the start position of the headword is used as the compression boundary. However, the start position of the headword and the start position of the example sentence of the headword may be used as the compression boundary.

  In the above embodiment, the encoding device 100 and the decoding device 200 are described as devices independent of each other. However, the encoding apparatus 100 may have all the functions of the decoding apparatus 200 and operate as a decoding apparatus, or the decoding apparatus 200 may have all the functions of the encoding apparatus 100 and operate as an encoding apparatus. Good.

  In addition, the decoding device 200 may include a specifying unit that specifies data to be decoded from the compressed data. Then, in step S30 of the decoding process shown in FIG. 12, the specifying unit may specify the data to be decoded from the compressed data. In this case, the bit string identification number decoding unit 206 decodes the decoding target data specified by the specifying unit.

  It should be noted that, in addition to being able to be provided as an encoding device and a decoding device provided in advance with the configuration for realizing the functions according to the present invention, an existing personal computer, an information terminal device, etc. can be installed according to the present invention by applying a program. It can also function as an encoding device or a decoding device. That is, by applying the program for realizing each functional configuration by the encoding device and the decoding device exemplified in the above embodiment so that a CPU or the like that controls an existing personal computer or information terminal device can be executed, The coding apparatus and decoding apparatus according to the present invention can be made to function. The encoding method and decoding method according to the present invention can be implemented using an encoding device and a decoding device.

  Moreover, the application method of such a program is arbitrary. For example, the program can be stored and applied to a computer-readable recording medium [CD-ROM (Compact Disc Read-Only Memory), DVD (Digital Versatile Disc), MO (Magneto Optical disc), etc.], the Internet, etc. It is also possible to apply the program by storing it in a storage on the network and downloading it.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention includes the invention described in the claims and the equivalent scope thereof. included. Hereinafter, the invention described in the scope of claims of the present application will be appended.

(Appendix 1)
A character identification number storage unit that stores a character included in data to be encoded and a character identification number for identifying the character in association with each other;
A conversion unit that refers to the character identification number storage unit and converts a character included in the data to be encoded into a character identification number associated with the character;
An encoding unit that encodes the character identification number converted by the conversion unit into binary data;
A bit string identification number associating unit that associates a bit string identification number that identifies the bit string and stores it in the bit string identification number storage unit for each identical bit string that appears in the binary data of the character identification number encoded by the encoding unit;
A bit string identification number converter that converts the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Encoding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted by the bit string identification number conversion unit, and encoding the bit string identification number into binary data And
An encoding device comprising:

(Appendix 2)
The character identification number is smaller as it is associated with a character having a high appearance frequency in the data to be encoded,
The encoding unit encodes the character identification number into binary data using an encoding method in which the amount of binary data obtained by encoding the character identification number is smaller as the character identification number is smaller.
The encoding device according to attachment 1.

(Appendix 3)
Among the bit strings appearing in the binary data of the character identification number, for the bit string not associated with the bit string identification number, the number of bits from the beginning of the bit string until the bit string associated with the bit string identification number appears An encoding unit with a non-reference flag that associates a non-reference flag indicating that the bit string identification number storage unit is not referred to at the time of decoding and encodes the number of digits of the bit into binary data;
The encoding apparatus according to Supplementary Note 1 or 2, further comprising:

(Appendix 4)
The bit string identification number is smaller as it is associated with the same bit string that frequently appears in the binary data of the character identification number,
The encoding unit with a reference flag encodes the bit string identification number into binary data using an encoding method in which the smaller the bit string identification number, the smaller the amount of binary data obtained by encoding the bit string identification number. To
The encoding device according to any one of appendices 1 to 3.

(Appendix 5)
The encoding target data includes a headword,
The appearance frequency of the same bit string does not include the number of occurrences of the same bit string across the start position of the headword in the encoding target data.
The encoding device according to attachment 4.

(Appendix 6)
The encoding target data includes a headword,
The bit string identification number conversion unit, when the bit string associated with the bit string identification number straddles the start position of the headword, does not convert the bit string to the bit string identification number,
The encoding unit with a non-reference flag is the bit string straddling the bit string from the beginning of the bit string with respect to the bit string that the bit string identification number conversion unit does not convert to the bit string identification number among the bit strings associated with the bit string identification number. Associating the non-reference flag with the number of bits to the start position of the headword and encoding the number of bits into binary data;
The encoding device according to attachment 3.

(Appendix 7)
When the bit string not associated with the bit string identification number straddles the start position of the headword, the encoding unit with a non-reference flag sets the non-reference flag encoding unit to the number of bits from the beginning of the bit string to the start position. Associating a reference flag and encoding the number of digits of the bit into binary data;
The encoding device according to attachment 6.

(Appendix 8)
The number of digits of the same bit string stored in the bit string identification number storage unit is 32 digits.
The encoding device according to any one of appendices 1 to 7.

(Appendix 9)
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number A compressed data storage unit for storing compressed data,
A character identification number storage unit for storing the character included in the data to be encoded and the character identification number for identifying the character in association with each other;
A bit string identification number storage unit that associates and stores the bit string identification number for identifying the bit string for each identical bit string that appears in the binary data of each character identification number;
An input unit for inputting a condition for specifying data to be decrypted;
Among the compressed data stored in the compressed data storage unit, the data satisfying the condition is specified as the data to be decoded, and the binary data of the character identification number and the binary data of the bit string identification number constituting the specified decoding target data A bit string identification number decoding unit for decoding binary data of the bit string identification number into the bit string identification number,
A bit string identification number converting unit that converts the bit string identification number decoded by the bit string identification number decoding unit into a bit string associated with the bit string identification number with reference to the bit string identification number storage unit;
A decoding unit that decodes the binary data of the character identification number constituting the data to be decoded and the bit string converted by the bit string identification number conversion unit into the character identification number;
A conversion unit that refers to the character identification number storage unit and converts the character identification number decoded by the decoding unit into a character associated with the character identification number;
A decoding device comprising:

(Appendix 10)
The character included in the data to be encoded is referred to the character identification number storage unit that stores the character included in the data to be encoded and the character identification number that identifies the character in association with each other. A conversion step for converting to a character identification number associated with
An encoding step of encoding the character identification number converted in the conversion step into binary data;
A bit string identification number associating step for associating a bit string identification number for identifying the bit string and storing it in the bit string identification number storage unit for each identical bit string appearing in the binary data of the character identification number encoded in the encoding step;
A bit string identification number conversion step for converting the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Coding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted in the bit string identification number conversion step, and encoding the bit string identification number into binary data Steps,
An encoding method comprising:

(Appendix 11)
An input step for inputting conditions for specifying data to be decrypted;
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number Among the compressed data, a specific step of specifying data satisfying the condition as data to be decoded;
Bit string identification for decoding binary data of the bit string identification number into the bit string identification number of the binary data of the character identification number and the binary data of the bit string identification number constituting the data to be decoded identified in the identifying step A number decoding step;
Decoding in the bit string identification number decoding step with reference to a bit string identification number storage unit for storing the bit string identification number for identifying the bit string for each of the same bit strings appearing in the binary data of each character identification number Converting the bit string identification number into a bit string associated with the bit string identification number; and
A decoding step for decoding the character identification number binary data constituting the decoding target data and the bit string converted in the bit string identification number conversion step into the character identification number;
The character identification number decoded in the decoding step with reference to a character identification number storage unit that associates and stores the character included in the data to be encoded and the character identification number that identifies the character, A conversion step for converting to a character associated with the character identification number;
A decoding method comprising:

(Appendix 12)
Computer
The character included in the data to be encoded is referred to the character identification number storage unit that stores the character included in the data to be encoded and the character identification number that identifies the character in association with each other. A conversion unit for converting to a character identification number associated with
An encoding unit for encoding the character identification number into binary data by the conversion unit;
A bit string identification number associating unit that associates a bit string identification number that identifies the bit string and stores it in the bit string identification number storage unit for each identical bit string that appears in the binary data of the character identification number encoded by the encoding unit;
A bit string identification number converter that converts the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Encoding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted by the bit string identification number conversion unit, and encoding the bit string identification number into binary data Part,
Program to function as.

(Appendix 13)
Computer
An input unit for inputting a condition for specifying data to be decrypted;
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number Among the compressed data, a specifying unit that specifies data satisfying the condition as data to be decoded,
Bit string identification for decoding binary data of the bit string identification number into the bit string identification number of binary data of the character identification number and binary data of the bit string identification number constituting the data to be decoded specified by the specifying unit Number decoding part,
For each identical bit string appearing in the binary data of each character identification number, the bit string identification number decoding unit decodes with reference to a bit string identification number storage unit that stores the bit string identification number that identifies the bit string in association with each other. A bit string identification number converting unit that converts the bit string identification number into a bit string associated with the bit string identification number;
A decoding unit that decodes the binary data of the character identification number constituting the data to be decoded and the bit string converted by the bit string identification number conversion unit into the character identification number;
The character identification number decoded by the decoding unit with reference to a character identification number storage unit that associates and stores the character included in the data to be encoded and the character identification number that identifies the character, A conversion unit for converting into a character associated with the character identification number;
Program to function as.

DESCRIPTION OF SYMBOLS 1 ... Dictionary data, 2 ... Binary data before final encoding, 10 ... ROM, 11 ... RAM, 12 ... External storage device, 13 ... Input device, 14 ... Display device, 15 ... CPU, 100 ... Encoding device, 101 ... Encoding candidate data storage unit, 102 ... display unit, 103 ... input unit, 104 ... character appearance frequency acquisition unit, 105 ... character identification number association unit, 106 ... character identification number storage unit, 107 ... conversion unit, 108 ... code 109: Start position storage unit, 110: Bit string appearance frequency acquisition unit, 111 ... Bit string identification number association unit, 112 ... Bit string identification number storage unit, 113 ... Bit string identification number conversion unit, 114 ... Coding with reference flag 115: Encoding unit with non-reference flag, 116 ... Compressed data storage unit, 200 ... Decoding device, 20 ... ROM, 21 ... RAM, 22 ... External storage device, 23 ... On Device: 24 ... Display device 25 ... CPU 200 ... Decoding device 201 ... Bit string identification number storage unit 202 ... Compressed data storage unit 203 ... Start position storage unit 204 ... Bit string identification number decoding method storage unit 205 ... Input unit 206 ... Bit string identification number decoding unit, 207 ... Bit string identification number conversion unit, 208 ... Character identification number decoding method storage unit, 209 ... Character identification number storage unit, 210 ... Decoding unit, 211 ... Conversion unit, 212 ... Display Part

Claims (13)

A character identification number storage unit that stores a character included in data to be encoded and a character identification number for identifying the character in association with each other;
A conversion unit that refers to the character identification number storage unit and converts a character included in the data to be encoded into a character identification number associated with the character;
An encoding unit that encodes the character identification number converted by the conversion unit into binary data;
A bit string identification number associating unit that associates a bit string identification number that identifies the bit string and stores it in the bit string identification number storage unit for each identical bit string that appears in the binary data of the character identification number encoded by the encoding unit;
A bit string identification number converter that converts the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Encoding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted by the bit string identification number conversion unit, and encoding the bit string identification number into binary data And
An encoding device comprising: The character identification number is smaller as it is associated with a character having a high appearance frequency in the data to be encoded,
The encoding unit encodes the character identification number into binary data using an encoding method in which the amount of binary data obtained by encoding the character identification number is smaller as the character identification number is smaller.
The encoding device according to claim 1. Among the bit strings appearing in the binary data of the character identification number, for the bit string not associated with the bit string identification number, the number of bits from the beginning of the bit string until the bit string associated with the bit string identification number appears An encoding unit with a non-reference flag that associates a non-reference flag indicating that the bit string identification number storage unit is not referred to at the time of decoding and encodes the number of digits of the bit into binary data;
The encoding device according to claim 1, comprising: The bit string identification number is smaller as it is associated with the same bit string that frequently appears in the binary data of the character identification number,
The encoding unit with a reference flag encodes the bit string identification number into binary data using an encoding method in which the smaller the bit string identification number, the smaller the amount of binary data obtained by encoding the bit string identification number. To
The encoding apparatus as described in any one of Claims 1 thru | or 3. The encoding target data includes a headword,
The appearance frequency of the same bit string does not include the number of occurrences of the same bit string across the start position of the headword in the encoding target data.
The encoding device according to claim 4. The encoding target data includes a headword,
The bit string identification number conversion unit, when the bit string associated with the bit string identification number straddles the start position of the headword, does not convert the bit string to the bit string identification number,
The encoding unit with a non-reference flag is the bit string straddling the bit string from the beginning of the bit string with respect to the bit string that the bit string identification number conversion unit does not convert to the bit string identification number among the bit strings associated with the bit string identification number. Associating the non-reference flag with the number of bits to the start position of the headword and encoding the number of bits into binary data;
The encoding device according to claim 3. When the bit string not associated with the bit string identification number straddles the start position of the headword, the encoding unit with a non-reference flag sets the non-reference flag encoding unit to the number of bits from the beginning of the bit string to the start position. Associating a reference flag and encoding the number of digits of the bit into binary data;
The encoding device according to claim 6. The number of digits of the same bit string stored in the bit string identification number storage unit is 32 digits.
The encoding device according to any one of claims 1 to 7. It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number A compressed data storage unit for storing compressed data,
A character identification number storage unit for storing the character included in the data to be encoded and the character identification number for identifying the character in association with each other;
A bit string identification number storage unit that associates and stores the bit string identification number for identifying the bit string for each identical bit string that appears in the binary data of each character identification number;
An input unit for inputting a condition for specifying data to be decrypted;
Among the compressed data stored in the compressed data storage unit, the data satisfying the condition is specified as the data to be decoded, and the binary data of the character identification number and the binary data of the bit string identification number constituting the specified decoding target data A bit string identification number decoding unit for decoding binary data of the bit string identification number into the bit string identification number,
A bit string identification number converting unit that converts the bit string identification number decoded by the bit string identification number decoding unit into a bit string associated with the bit string identification number with reference to the bit string identification number storage unit;
A decoding unit that decodes the binary data of the character identification number constituting the data to be decoded and the bit string converted by the bit string identification number conversion unit into the character identification number;
A conversion unit that refers to the character identification number storage unit and converts the character identification number decoded by the decoding unit into a character associated with the character identification number;
A decoding device comprising: The character included in the data to be encoded is referred to the character identification number storage unit that stores the character included in the data to be encoded and the character identification number that identifies the character in association with each other. A conversion step for converting to a character identification number associated with
An encoding step of encoding the character identification number converted in the conversion step into binary data;
A bit string identification number associating step for associating a bit string identification number for identifying the bit string and storing it in the bit string identification number storage unit for each identical bit string appearing in the binary data of the character identification number encoded in the encoding step;
A bit string identification number conversion step for converting the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Coding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted in the bit string identification number conversion step, and encoding the bit string identification number into binary data Steps,
An encoding method comprising: An input step for inputting conditions for specifying data to be decrypted;
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number Among the compressed data, a specific step of specifying data satisfying the condition as data to be decoded;
Bit string identification for decoding binary data of the bit string identification number into the bit string identification number of the binary data of the character identification number and the binary data of the bit string identification number constituting the data to be decoded identified in the identifying step A number decoding step;
Decoding in the bit string identification number decoding step with reference to a bit string identification number storage unit for storing the bit string identification number for identifying the bit string for each of the same bit strings appearing in the binary data of each character identification number Converting the bit string identification number into a bit string associated with the bit string identification number; and
A decoding step for decoding the character identification number binary data constituting the decoding target data and the bit string converted in the bit string identification number conversion step into the character identification number;
The character identification number decoded in the decoding step with reference to a character identification number storage unit that associates and stores the character included in the data to be encoded and the character identification number that identifies the character, A conversion step for converting to a character associated with the character identification number;
A decoding method comprising: Computer
The character included in the data to be encoded is referred to the character identification number storage unit that stores the character included in the data to be encoded and the character identification number that identifies the character in association with each other. A conversion unit for converting to a character identification number associated with
An encoding unit for encoding the character identification number into binary data by the conversion unit;
A bit string identification number associating unit that associates a bit string identification number that identifies the bit string and stores it in the bit string identification number storage unit for each identical bit string that appears in the binary data of the character identification number encoded by the encoding unit;
A bit string identification number converter that converts the same bit string appearing in the binary data of the character identification number into a bit string identification number associated with the bit string with reference to the bit string identification number storage unit;
Encoding with a reference flag for associating a reference flag indicating that the bit string identification number storage unit is referred to at the time of decoding with the bit string identification number converted by the bit string identification number conversion unit, and encoding the bit string identification number into binary data Part,
Program to function as. Computer
An input unit for inputting a condition for specifying data to be decrypted;
It consists of binary data of each character identification number that identifies each character included in the data to be encoded, and binary data of a bit string identification number that identifies the same bit string that appears in the binary data of each character identification number Among the compressed data, a specifying unit that specifies data satisfying the condition as data to be decoded,
Bit string identification for decoding binary data of the bit string identification number into the bit string identification number of binary data of the character identification number and binary data of the bit string identification number constituting the data to be decoded specified by the specifying unit Number decoding part,
For each identical bit string appearing in the binary data of each character identification number, the bit string identification number decoding unit decodes with reference to a bit string identification number storage unit that stores the bit string identification number that identifies the bit string in association with each other. A bit string identification number converting unit that converts the bit string identification number into a bit string associated with the bit string identification number;
A decoding unit that decodes the binary data of the character identification number constituting the data to be decoded and the bit string converted by the bit string identification number conversion unit into the character identification number;
The character identification number decoded by the decoding unit with reference to a character identification number storage unit that associates and stores the character included in the data to be encoded and the character identification number that identifies the character, A conversion unit for converting into a character associated with the character identification number;
Program to function as.

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