Code processing technique

A computer-readable, non-transitory storage medium storing a program for causing a computer to execute a process, the process comprising:

• first generating a data block including a first area for holding a code for a character or a character string, a second area for holding, for each character that will be used, an appearance sequential number of a second character that appears next to the character or the character string, and a third area for holding, according to the appearance sequential number, a number of appearances or a code corresponding to a character string comprising the character or the character string and the second character when the number of appearances exceeds a threshold, for each character that will be used, and each character that appears a predetermined number of times or more next to a character or a character string in an input character string, for which the data block has already been generated;
• second generating, from a plurality of data blocks generated for the input character string, first correlation data to correlate data representing a root in a tree structure represented by the plurality of data blocks in a specific state or a greatest code among codes of child data blocks for each data block of data blocks in a first layer in the tree structure with a character code for each data block of the data blocks in the first layer in the tree structure and a layer number of the data block, and second correlation data to correlate, for each data block of data blocks in a second layer and subsequent layers of the tree structure, a code for a parent data block of the data block or a greatest code among codes of child data blocks of the data block with a character code corresponding to an added character for the data block and a layer number of the data block, wherein the specific state is a state where first codes held in the first area and the third area of the plurality of data blocks are reassigned to second codes based on order of characters or character strings that correspond to the first codes;
• third generating first data including, for each data block in each layer of the second layer and the subsequent layers of the tree structure, a code for a character string corresponding to the second code held in the first area of the data block;
• and
• fourth generating layer information to correlate, for each layer of the second layer and the subsequent layers of the tree structure, a number of data blocks in the layer with a least second code of the second codes held in the first areas of the data blocks in the layer and an offset value of a position of a character or a character string corresponding to the least second code in the first data from a beginning of the first data.

A computer-readable, non-transitory storage medium storing a data structure, which is used by a computer, the data structure comprising:

• first data corresponding to a phrase tree;
• second data for a character or a character string, which corresponds to each node in the phrase tree;
• and
• third data for layers of the phrase tree,
• wherein the first data comprises, for each node of the phrase tree, correlation data to correlate a code for a parent node of the node or a greatest code among codes of child nodes of the node with a code for a character, which is represented by the node, and a layer identifier of a layer to which the node belongs, wherein the correlation data is arranged in order of a code assigned to the node,
• the second data includes, for each node in each layer of a second layer and subsequent layers in the phrase tree, a code for a character or a character string, which corresponds to the node, in order of the code assigned to the node, and
• the third data includes, for each layer of the second layer and the subsequent layers in the phrase tree, a number of nodes belonging to the layer, a least code among codes of nodes belonging to the layer, and an offset value of a position of a character or a character string corresponding to the least code in the second data from a beginning of the second data.

An information processing method, comprising:

• first generating, by using a computer, for each character that will be used, a data block including a first area for holding a code for a character or a character string, a second area for holding, for each character that will be used, an appearance sequential number of a second character that appears next to the character or the character string, and a third area for holding, according to the appearance sequential number, a number of appearances or a code corresponding to a character string comprising the character or the character string and the second character when the number of appearances exceeds a threshold;
• upon detecting that, in a second area of a data block for a character or a character string being processed among a plurality of characters included in an input character string, an appearance sequential number for a next character of the character or the character string being processed in the input character string is held, that, in a third area of the data block, a number of appearances is held as data in the appearance sequential number, and that the number of appearances after increment exceeds the threshold, storing, by using the computer, a code corresponding to a second character string comprising the character or the character string being processed and the next character;
• and
• generating, by using the computer, a data block for the second character string, which has a same structure as the data block generated in the first generating.

An information processing apparatus, comprising:

• a memory;
• and
• a processor configured to use the memory and execute a process, the process comprising:
• first generating, for each character that will be used, a data block including a first area for holding a code for a character or a character string, a second area for holding, for each character that will be used, an appearance sequential number of a second character that appears next to the character or the character string, and a third area for holding, according to the appearance sequential number, a number of appearances or a code corresponding to a character string comprising the character or the character string and the second character when the number of appearances exceeds a threshold;
• upon detecting that, in a second area of a data block for a character or a character string being processed among a plurality of characters included in an input character string, an appearance sequential number for a next character of the character or the character string being processed in the input character string is held, that, in a third area of the data block, a number of appearances is held as data in the appearance sequential number, and that the number of appearances after increment exceeds the threshold, storing a code corresponding to a second character string comprising the character or the character string being processed and the next character;
• and
• generating a data block for the second character string, which has a same structure as the data block generated in the first generating.