Data compression method and data decompression device corresponding thereto

A data compression method comprising:

• calculating first frequencies of occurrence of different original codewords, wherein each of the original codewords has at least two sub-words and each of the sub-words has at least one bit;
• calculating second frequencies of occurrence of all the different sub-words based on the first frequencies;
• recoding the sub-words of the original codewords;
• decomposing each of the original codewords into the at least two recoded sub-words;
• calculating third frequencies of occurrence of all the different recoded sub-words based on the first frequencies, wherein a distribution of the third frequencies corresponding to all the different recoded sub-words is more extreme than a distribution of the second frequencies corresponding to all the different unrecoded sub-words;
• performing variable-length coding on all the different recoded sub-words in a compression manner to respectively generate different compression codes corresponding to all the different recoded sub-words, wherein a coding length of the compression code corresponding to the higher third frequency is less than or equal to a coding length of the compression code corresponding to the lower third frequency;
• and
• respectively converting the original codewords into encoded codewords based on a corresponding relationship between the compression codes and all the different recoded sub-words.