Read N Characters from 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.

 1 /* The read4 API is defined in the parent class Reader4.
 2       int read4(char[] buf); */
 3 
 4 public class Solution extends Reader4 {
 5     /**
 6      * @param buf Destination buffer
 7      * @param n   Maximum number of characters to read
 8      * @return    The number of characters read
 9      */
10     public int read(char[] buf, int n) {
11         char[] temp = new char[4];
12         int count = 0;
13         while (count < n) {
14             int currentCount = read4(temp);
15             if (currentCount == 0) break;
16             
17             int index = 0;
18             while (index < currentCount && count < n)
19                 buf[count++] = temp[index++];
20         }
21         return count;
22     }
23 }