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.

Code:

  public int read(char[] buf, int n) {
    if (buf == null || buf.length == 0 || n <= 0) {
        return 0;
    }
    for (int i = 0; i < n; i += 4) {
        char[] temp = new char[4];
        int length = read4(temp);
        System.arraycopy(temp, 0, buf, i, Math.min(length, n - i));
        if (length < 4) {
            return Math.min(i + length, n);
        }
    }
    return n;
  }

奇怪做法：

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) {
        boolean eof = false;      // end of file flag
        int total = 0;            // total bytes have read
        char[] tmp = new char[4]; // temp buffer

        while (!eof && total < n) {
            int count = read4(tmp);
            // check if it's the end of the file
            eof = count < 4;
            // get the actual count
            count = Math.min(count, n - total);

            // copy from temp buffer to buf
            for (int i = 0; i < count; i++) {
                buf[total++] = tmp[i];
            } 
      }
      return total;
    }
 }