/***********************************************************************
 * testFifo.c
 *
 * Perform some rudimentary testing of the fifo device.  Emphasis on
 * the rudimentary.  Asserts are used to confirm correct functionality.
 * This program should be able to successfully run an arbitrary number
 * of times without unloading and reloading the module.  If not, your
 * fifo is faulty.
 *
 * Running the program without the fifo loaded should result in a
 * failure of the first assertion ('file >= 0').
 *
 * Add your tests below, as indicated by the pair of comments near the
 * end of the file.
 ***********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <string.h>
#include <assert.h>
#include "fifodev.h"


/***********************************************************************
 * main()
 ***********************************************************************/

int main()
{
   int file;   /* File descriptor for fifo device. */

   /* Just a string used for testing
    * later.
    */

   char hw[] = "Hello world.\n";

   /* Buffer0 and bd0 (buffer descriptor).  This is used for receiving
    * data from the fifo.
    */

   char buffer0[FIFO_LEN + 1];
   buffer_descriptor bd0 = {
      .buffer = buffer0,
      .len = FIFO_LEN
   };

   /* Buffer1 and bd1.  This is used for writing data to the fifo. */

   char buffer1[FIFO_LEN] = "DATA data\n";
   buffer_descriptor bd1 = {
      .buffer = buffer1,
      .len = 10
   };

   /* Check that device can be opened correctly and that we can't open an
    * open device.
    */

   file = open(DEVICE_FILE_NAME, O_RDWR);
   assert(file >= 0);
   assert(open(DEVICE_FILE_NAME, O_RDWR) < 0);

   /* Return the fifo to a known initial state to begin testing. */

   ioctl(file, IOCTL_READ_FIFO, &bd0);
   ioctl(file, IOCTL_SET_IMODE, STOP);
   ioctl(file, IOCTL_SET_PMODE, NORMAL);

   /* Check processing mode functionality. */

   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 10);
   ioctl(file, IOCTL_SET_PMODE, WHISPER);
   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 10);
   ioctl(file, IOCTL_SET_PMODE, SHOUT);
   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 10);
   assert(ioctl(file, IOCTL_READ_FIFO, &bd0) == 30);
   buffer0[30] = '\0';
   printf("%s", buffer0);
   assert(strcmp(buffer0, "DATA data\ndata data\nDATA DATA\n") == 0);

   /* Check input mode functionality, STOP mode first. */

   strcpy(buffer1, "12345678901234567890");
   bd1.len = 20;
   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 20);
   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 12);
   assert(ioctl(file, IOCTL_READ_FIFO, &bd0) == 32);
   buffer0[32] = '\0';
   printf("%s\n", buffer0);
   assert(strcmp(buffer0, "12345678901234567890123456789012") == 0);

   /* Now check OVERWRITE mode. */

   ioctl(file, IOCTL_SET_IMODE, OVERWRITE);

   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 20);
   assert(ioctl(file, IOCTL_WRITE_FIFO, &bd1) == 20);
   assert(ioctl(file, IOCTL_READ_FIFO, &bd0) == 32);
   buffer0[32] = '\0';
   printf("%s\n", buffer0);
   assert(strcmp(buffer0, "90123456789012345678901234567890") == 0);

   /* Perform a few filesystem access tests. */

   ioctl(file, IOCTL_SET_PMODE, NORMAL);
   assert(write(file, hw, strlen(hw)) == strlen(hw));
   assert(read(file, buffer0, 6) == 6);
   assert(read(file, buffer0, FIFO_LEN) == 7);
   buffer0[7] = '\0';
   printf("%s", buffer0);
   assert(strcmp(buffer0, "world.\n") == 0);


   /*********** Add your tests below this line. ***********/




   /*********** Add your tests above this line. ***********/


   /* Close the device and confirm that we can't close a closed device. */

   assert(close(file) == 0);
   assert(close(file) == -1);

   return 0;
}