Read N Characters Given Read4

The API: int read4(char *buf) reads 4 characters at a time from a file.
The return value is the actual number of characters read. For example, it returns 3 if there is only 3 characters left in the file.
By using the read4 API, implement the function int read(char *buf, int n) that reads n characters from the file.
Note:
The read function will only be called once for each test case.

/* The read4 API is defined in the parent class Reader4.
      int read4(char[] buf); */

public class Solution extends Reader4 {
   
    /**
     * @param buf Destination buffer
     * @param n   Maximum number of characters to read
     * @return    The number of characters read
     */
    public int read(char[] buf, int n) {
        int cur = 0;
        char[] buf4 = new char[4];
        while (true) {
            int len = read4(buf4);
            for (int i = 0; i < len && cur < n; i++) {
                buf[cur++] = buf4[i];
            }
            if (len < 4 || cur == n) {
                break;
            }
        }
        return cur;
    }
}