#include <stdio.h>
#include <unistd.h>
#include "hfh_hdr_def.h"

/*   
	  fd is the file descriptor returned by open(... it is assumed that the
	  file has already been opened for reading and the space for the header
	  has been allocated
*/

int read_hfh_header(int fd, hfh_img_hdr *header)
{
  int bytes;

/* read each item individually (Sparc systems align double floating point) */

  bytes = read(fd, (void *) header->image_label, (size_t) 64);
  bytes += read(fd, (void *) &header->revision_num, (size_t) 1);
  bytes += read(fd, (void *) &header->orient, (size_t) 1);
  bytes += read(fd, (void *) &header->file_flag, (size_t) 1);
  bytes += read(fd, (void *) &header->compress, (size_t) 1);
  bytes += read(fd, (void *) &header->bits_gray, (size_t) 2);
  bytes += read(fd, (void *) &header->bits_pixel, (size_t) 2);
  bytes += read(fd, (void *) &header->row, (size_t) 2);
  bytes += read(fd, (void *) &header->colm, (size_t) 2);
  bytes += read(fd, (void *) &header->max_value, (size_t) 2);
  bytes += read(fd, (void *) &header->min_value, (size_t) 2);
  bytes += read(fd, (void *) &header->xpix_size, (size_t) 4);
  bytes += read(fd, (void *) &header->ypix_size, (size_t) 4);
  bytes += read(fd, (void *) &header->zpix_size, (size_t) 4);
  bytes += read(fd, (void *) &header->sequence_value, (size_t) 4);
  bytes += read(fd, (void *) &header->pixel_data, (size_t) 4);
  bytes += read(fd, (void *) &header->d_max_value, (size_t) 8);
  bytes += read(fd, (void *) &header->d_min_value, (size_t) 8);
  bytes += read(fd, (void *) &header->byte_order, (size_t) 1);
  bytes += read(fd, (void *) &header->int_format, (size_t) 1);
  bytes += read(fd, (void *) &header->fp_format, (size_t) 1);
  bytes += read(fd, (void *) header->id, (size_t) 4);
  bytes += read(fd, (void *) &header->slices, (size_t) 2); /* should always be 0 */
  bytes += read(fd, (void *) header->temp, (size_t) 3);

/* add the following only if using the code and files on intel architecture */

#ifdef i386
  swab((char *) &header->bits_gray, (char *) &header->bits_gray, (size_t) (6*sizeof(short)));
  swab((char *) &header->slices, (char *) &header->slices, (size_t) (1*sizeof(short)));
  swap_byte_and_word((long int *) &header->xpix_size);
  swap_byte_and_word((long int *) &header->ypix_size);
  swap_byte_and_word((long int *) &header->zpix_size);
  swap_byte_and_word((long int *) &header->sequence_value);
  swap_byte_and_word((long int *) &header->pixel_data);
  swab((char *) &header->d_max_value, (char *) &header->d_max_value, (size_t) (2*sizeof(double)));
  i386_sparc_double(&header->d_max_value);
  i386_sparc_double(&header->d_min_value);
#endif

/* return the # bytes successfully read */

  return bytes;
}

/*   
	  fd is the file descriptor returned by open(... it is assumed that the
	  file has already been opened for writing and the space for the header 
	  has been allocated
*/

int write_hfh_header(int fd, hfh_img_hdr *header)
{
  int bytes;

/* add the following only if using the code and files on intel architecture */

#ifdef i386
  swab((char *) &header->bits_gray, (char *) &header->bits_gray, (size_t) (6*sizeof(short)));
  swab((char *) &header->slices, (char *) &header->slices, (size_t) (1*sizeof(short)));
  swap_byte_and_word((long int *) &header->xpix_size);
  swap_byte_and_word((long int *) &header->ypix_size);
  swap_byte_and_word((long int *) &header->zpix_size);
  swap_byte_and_word((long int *) &header->sequence_value);
  swap_byte_and_word((long int *) &header->pixel_data);
  swab((char *) &header->d_max_value, (char *) &header->d_max_value, (size_t) (2*sizeof(double)));
  i386_sparc_double(&header->d_max_value);
  i386_sparc_double(&header->d_min_value);
#endif

/* write each item individually to preserve 128-byte size (Sparc systems align double floating point) */

  bytes = write(fd, (void *) header->image_label, (size_t) 64);
  bytes += write(fd, (void *) &header->revision_num, (size_t) 1);
  bytes += write(fd, (void *) &header->orient, (size_t) 1);
  bytes += write(fd, (void *) &header->file_flag, (size_t) 1);
  bytes += write(fd, (void *) &header->compress, (size_t) 1);
  bytes += write(fd, (void *) &header->bits_gray, (size_t) 2);
  bytes += write(fd, (void *) &header->bits_pixel, (size_t) 2);
  bytes += write(fd, (void *) &header->row, (size_t) 2);
  bytes += write(fd, (void *) &header->colm, (size_t) 2);
  bytes += write(fd, (void *) &header->max_value, (size_t) 2);
  bytes += write(fd, (void *) &header->min_value, (size_t) 2);
  bytes += write(fd, (void *) &header->xpix_size, (size_t) 4);
  bytes += write(fd, (void *) &header->ypix_size, (size_t) 4);
  bytes += write(fd, (void *) &header->zpix_size, (size_t) 4);
  bytes += write(fd, (void *) &header->sequence_value, (size_t) 4);
  bytes += write(fd, (void *) &header->pixel_data, (size_t) 4);
  bytes += write(fd, (void *) &header->d_max_value, (size_t) 8);
  bytes += write(fd, (void *) &header->d_min_value, (size_t) 8);
  bytes += write(fd, (void *) &header->byte_order, (size_t) 1);
  bytes += write(fd, (void *) &header->int_format, (size_t) 1);
  bytes += write(fd, (void *) &header->fp_format, (size_t) 1);
  bytes += write(fd, (void *) header->id, (size_t) 4);
  bytes += write(fd, (void *) &header->slices, (size_t) 2); /* should always be 0 */
  bytes += write(fd, (void *) header->temp, (size_t) 3);

/* return the # bytes successfully written */

  return bytes;
}

void swap_byte_and_word(long int *value)
{
  long int return_value, a, b;

  swab((char *) value, (char *) value, sizeof(long int));
  a = 0x0000ffff & ((0xffff0000 & *value) >> 16);
  b = 0xffff0000 & ((0x0000ffff & *value) << 16);
  return_value = a | b;
  *value = return_value;
}

void i386_sparc_double(double *value)
{
  short convert_value[4], temp_value[4];

  memcpy((char *) temp_value, (char *) value, 8);
  convert_value[0] = temp_value[3];
  convert_value[1] = temp_value[2];
  convert_value[2] = temp_value[1];
  convert_value[3] = temp_value[0];
  memcpy((char *) value, (char *) convert_value, 8);
}