steganography.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "steganography_util.h"
#include "steganography_common.h"

/*
*   Function: encode
*   ----------------------
*   Encodes the image with the message
*
*   Parameters:
*       inputFile: the name of the input file
*       messageFile: the name of the message file
*       outputFile: the name of the output file
*
*   returns: void
*/
void
encode (char *inputFile, char *messageFile, char *outputFile)
{
  struct ImageInfo decodedImageInfo, encodedImageInfo;

  //  decode image
  decode_image (inputFile, &decodedImageInfo);

  // copy decoded image info to encoded image info
  memcpy (&encodedImageInfo, &decodedImageInfo, sizeof (decodedImageInfo));

  // apply LSB algorithm to encode image
  LSBAlgorithm (decodedImageInfo, messageFile, &encodedImageInfo);

  // encode image
  encode_image (outputFile, &encodedImageInfo);
}

/*
*   Function: decode
*   ----------------------
*   Decodes the image and stores the message in the output file
*
*   Parameters:
*       inputFile: the name of the input file
*       outputFile: the name of the output file
*
*   returns: void
*/
void
decode (char *inputFile, char *outputFile)
{
  struct ImageInfo decodedImageInfo;

  decode_image (inputFile, &decodedImageInfo);

  size_t imageSize = decodedImageInfo.width * decodedImageInfo.height * 4;

  // allocate memory for binary number
  int
    *binary = malloc (sizeof (int) * BYTE),
    *binBuffer = malloc (sizeof (int) * BYTE),
    *decimal = malloc (sizeof (int)),
    *reversedBinary = malloc (sizeof (int) * BYTE), count = 0;

  FILE *file = fopen (outputFile, "w");
  if (file == NULL)
  {
    printf ("Error opening file!\n");
    exit (EXIT_FAILURE);
  }

  for (int i = 0; i < imageSize; i++)
  {

    // convert decimal to binary
    decimal2binary (decodedImageInfo.image[i], binary);


    if (count < BYTE)
    {
      binBuffer[count] = binary[0];
      if (count == 7)
      {
        *decimal = 0;
        reverse (binBuffer, reversedBinary);
        binary2decimal (reversedBinary, decimal);

        if (*decimal != 0)
        {
          fprintf (file, "%c", *decimal);
        }
        else
        {
          exit (EXIT_SUCCESS);
        }

      }

      count++;
    }

    if (count == BYTE)
      count = 0;
  }

  fclose (file);
}