Lossless compression and decompression method for data

A lossless compression method for data, comprising the following steps:

• S101. reading a to-be-compressed file, obtaining raw data in hexadecimal of the file, reading the first eight bytes of the raw data to obtain a first to-be-processed data;
• S102. determining whether there is at least one digit in the first to-be-processed data that satisfies 0-F;
• selecting sequentially a half byte from the ninth byte of the raw data and adding it to a tail part of the first to-be-processed data until the condition is met to obtain a second to-be-processed data when the at least one digit in the first to-be-processed data does not satisfy 0-F;
• or taking the first to-be-processes data as the second to-be-processed data when the at least one digit in the first to-be processed data satisfies 0-F;
• S103. obtaining a data length based on the second to-be-processed data, converting it to hexadecimal, saving it as data A;
• obtaining remaining data in the second to-be-processed data except for the last four bytes and saving it as data B;
• S104. selecting the last four bytes of the second to-be-processed data and performing a rule operation to obtain a third calculation result;
• converting the third calculation result to hexadecimal and saving it as data C;
• S105. obtaining a reference digit of the last four bytes of the second to-be-processed data, arranging and combining the reference digit in an orderly manner according to a setting rule, saving a calculation result as all combinations of the third calculation result;
• searching for a combination of the last four bytes of the second to-be-processed data from a saved combination, obtaining its arrangement rank;
• converting the arrangement rank to hexadecimal and saving it as data D;
• S106. obtaining compressed data according to a formula of data A plus data B plus data C plus data D;
• S107. selecting sequentially next eight bytes from the raw data that has never been read, repeating steps S102-S106 until all bytes have been selected and ending an operation.