docs: public int read(char ch[], int offset, int length) throws IOException {
          if (length > fBuffer.length) {
              length = fBuffer.length;
          }
          int count = fInputStream.read(fBuffer, 0, length);
          for (int i = 0; i < count; i++) {
              int b0 = fBuffer[i];
              if (b0 > 0x80) {
              	String msg = JspCoreException.getMsg("jsp.error.xml.invalidASCII", new Object[] {Integer.toString(b0)});
                  throw new IOException(msg);
              }
              ch[offset + i] = (char)b0;
          }
          return count;
      }