Custom Text File Data Reading Function with Multiple Read Modes

A self-developed function for reading text file data that supports multiple reading modes including full file reading, reading specific line N, reading lines from M to N, reading from line M to the Nth line from the end, and reading data starting from (or ending at) the M-th occurrence (including last occurrence or M-th from last) of a specific string. This function provides flexible text file manipulation capabilities and includes implementation details about line-by-line processing, string pattern matching, and efficient memory handling for large files.