Non-transitory computer-readable recording medium, encoding method, encoding device, decoding method, and decoding device

An encoding method, comprising:

• first generating static-encoded data from input text data, utilizing a static dictionary that associates a character strings and static codes, respectively the static-encoded data including a plurality of static codes corresponding to a plurality of character strings that are registered in the static dictionary and character strings that are not registered in the static dictionary among the text data, using a processor;
• second generating dynamic-encoded data from the static-encoded data by either encoding a character string that occurs more than once in the static-encoded data into a dynamic code or encoding a static code that occurs more than once in the static-encoded data, using the processor;
• first creating a dynamic dictionary associating character strings or static codes with corresponding dynamic codes, respectively, using the processor;
• and
• second creating a Huffman tree and data of a leaf in the Huffman tree based on an occurrence frequency of the dynamic codes and the static codes in the input text data, using the processor.

An encoding device, comprising:

• a processor that executes a process comprising:
• first generating static-encoded data from input text data, utilizing a static dictionary that associates a character strings and static codes, respectively the static-encoded data including a plurality of static codes corresponding to a plurality of character strings that are registered in the static dictionary and character strings that are not registered in the static dictionary among the text data;
• second generating dynamic-encoded data from the static-encoded data by either encoding a character string that occurs more than once in the static-encoded data into a dynamic code or encoding a static code that occurs more than once in the static-encoded data;
• first creating a dynamic dictionary associating character strings or static codes with corresponding dynamic codes, respectively;
• and
• second creating a Huffman tree and data of a leaf in the Huffman tree based on an occurrence frequency of the dynamic codes and the static codes in the input text data.

A non-transitory computer-readable recording medium having stored therein a decoding program that causes a computer to execute a process comprising:

• reading occurrence-frequency table data from a header portion of an encoded file to be input;
• creating a Huffman tree and data of a leaf in the Huffman tree based on information relating to an occurrence frequency of dynamic codes and static codes obtained from the occurrence-frequency table data, wherein the dynamic codes include a dynamic code which is encoded from a character string that occurs more than once in a static-encodes data, a dynamic code which is encoded from a static code that occurs more than once in the static-encodes data, a dynamic code which is encoded from combination data including a character string and a static code that occur more than once in the static-encodes data;
• and
• decoding an encoded file based on the Huffman tree, the data of a leaf in the Huffman tree, and encoded data included in the encoded file.

A decoding method, comprising:

• reading occurrence-frequency table data from a header portion of an encoded file to be input, using a processor;
• creating a Huffman tree and data of a leaf in the Huffman tree based on information relating to an occurrence frequency of dynamic codes and static codes obtained from the occurrence-frequency table data, wherein the dynamic codes include a dynamic code which is encoded from a character string that occurs more than once in a static-encodes data, a dynamic code which is encoded from a static code that occurs more than once in the static-encodes data, a dynamic code which is encoded from combination data including a character string and a static code that occur more than once in the static-encodes data, using the processor;
• and
• decoding an encoded file based on the Huffman tree, the data of a leaf in the Huffman tree, and encoded data included in the encoded file, using the processor.

A decoding device, comprising:

• a processor that executes a process comprising:
• reading occurrence-frequency table data from a header portion of an encoded file to be input;
• creating a Huffman tree and data of a leaf in the Huffman tree based on information relating to an occurrence frequency of dynamic codes and static codes obtained from the occurrence-frequency table data, wherein the dynamic codes include a dynamic code which is encoded from a character string that occurs more than once in a static-encodes data, a dynamic code which is encoded from a static code that occurs more than once in the static-encodes data, a dynamic code which is encoded from combination data including a character string and a static code that occur more than once in the static-encodes data;
• and
• decoding an encoded file based on the Huffman tree, the data of a leaf in the Huffman tree, and encoded data included in the encoded file.