#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "ppm.h"

static int get_next_action(FILE **fp)      // REQUER PONTEIRO PARA ARQUIVO ABERTO !!!!!!!!!!!!!
{
  char testchar;
  fpos_t position;

  do
  {
      fgetpos(*fp,&position);
      testchar = fgetc(*fp);
  }
  while ( (testchar == ' ') || (testchar == '\n') );

  switch (testchar)
  {
      case '#' : return 0;break;

      default  : fsetpos(*fp,&position);return 1;break;
  }
}
     

int ppm_read(int *p_w, int *p_h, unsigned char **p_rgb,char **comment, char *file_name)
{
  FILE *fp;
  char line[80];
  
  int rgb_size;
  int max,i;

  fp = fopen(file_name, "rb");
  if (fp == NULL) { printf("could not read from %s",file_name); return 0;}

  fgets(line,80,fp);
  if(strcmp(line,"P6\n")) { printf("\nO arquivo de entrada nao tem o formato ppm\n"); return 0;}

  while (!get_next_action(&fp))
  {
     fgets(line, 70, fp);
     
     for (i=0;i<70;i++)
     {
        if (line[i] == "\n")
           line[i] = "";
     }

     sprintf(*comment,"%s",line);
  }

  fscanf( fp, " %d ", p_w );
    
  while (!get_next_action(&fp))
  {
     fgets(line, 70, fp);
     for (i=0;i<70;i++)
     {
        if (line[i] == "\n")
           line[i] = "";
     }
     sprintf(*comment,"%s",line);

  } 

  fscanf( fp, " %d ", p_h );
	
  while (!get_next_action(&fp))
  {
     fgets(line, 70, fp);
     for (i=0;i<70;i++)
     {
        if (line[i] == "\n")
           line[i] = "";
     }
     sprintf(*comment,"%s",line);
  }
  
  fscanf( fp, " %d", &max ); 
  fgetc(fp);

  rgb_size=3*(*p_w)*(*p_h);
  (*p_rgb) = (unsigned char *) calloc(rgb_size, 1);
  if ((*p_rgb) != NULL) 
    fread( (*p_rgb), rgb_size, 1, fp );
 
  fclose(fp);
  return 1;
}


int ppm_write(int w, int h, unsigned char *rgb,char *comment, char *file_name)
{
  FILE *fp;

  fp = fopen(file_name, "wb");
  if (fp == NULL)
    return 0;

  fprintf(fp, "P6\n");
  fprintf(fp, "#%s\n", comment);
  fprintf(fp,"%d %d\n255\n", w, h);

  if (fwrite(rgb, 3*w*h, 1, fp) != 1)
  {
    fclose(fp);
    return 0;
  } 

  fclose(fp);
  return 1;
}