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) {
        char[] buffer = new char[4];
        boolean eof = false;
        int read = 0;//number of characters has been read
        
        while(!eof && read < n) {
            int count = read4(buffer);
            int remain = Math.min(count, n - read);
            
            if (count < 4)
                eof = true;
            
            System.arraycopy(buffer, 0, buf, read, remain);
            
            read = read + remain;
        }
        
        return read;
    }
}