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

#define XSTART 180
#define YSTART 100
#define WIDTH 1600
#define HEIGHT 700
#define SWIDTH 400
#define SHEIGHT 175
#define SHRINKRATIO 4

void printargs(int argc, char * argv[]);
void inputppm(char * filename, char *** red, char *** green, char *** blue);
void outputppm(char * outfilename, char **red, char **green, char **blue);
void outputshrunkenppm(char * outfilename, char **red, char **green, char **blue);

void main(int argc, char * argv[])
{
	char * infilename;
	FILE * infile;

	char ** red;
	char ** green;
	char ** blue;

	int i,j;

	printargs(argc, argv);

	if (argc < 2)
	{
		printf("Usage: gigo filename\n");
		exit(0);
	}
	
	infilename = argv[1];	

	if ((infile = fopen(infilename, "rb")) == NULL)
	{
		printf("Couldn't find %s\n", infilename);
		exit(0);
	}

	printf("Mallocing red[].\n");
	red = (char **) malloc (WIDTH * sizeof (char *));
	for (i=0; i<WIDTH; i++)
	{
		if (!(i %100)) 
			printf("Mallocing red[%d].\n", i);
		red[i] = (char *) malloc (HEIGHT * sizeof (char));
	}	

	printf("Mallocing green[].\n");
	green = (char **) malloc (WIDTH * sizeof (char *));
	for (i=0; i<WIDTH; i++)
	{
		if (!(i %100)) 
			printf("Mallocing green[%d].\n", i);
		green[i] = (char *) malloc (HEIGHT * sizeof (char));
	}	

	printf("Mallocing blue[].\n");
	blue = (char **) malloc (WIDTH * sizeof (char *));
	for (i=0; i<WIDTH; i++)
	{
		if (!(i %100)) 
			printf("Mallocing blue[%d].\n", i);
		blue[i] = (char *) malloc (HEIGHT * sizeof (char));
	}	

	inputppm(infilename, &red, &green, &blue);

	if (infilename[0] == 'q')  
	     infilename[0] = 'Q';
	else infilename[0] = 'q';

	outputshrunkenppm(infilename, red, green, blue);
}

void inputppm(char * filename, char *** red, char *** green, char *** blue)
{
	FILE * infile;
	int w, h, i, j;

	infile = fopen(filename, "rb");

	fscanf(infile, "P6\n%d %d\n255\n", &w, &h);  

	if (w != WIDTH || h != HEIGHT)
	{
		printf("Oops! w and h are %d, %d\n", w, h);
		exit(0);
	}

        for (j=0; j<HEIGHT; j++) 
        {
            if (!(j %100)) 
                printf("Reading line %d\n", j); 
            for (i=0; i<WIDTH; i++) 
            {
                fscanf(infile, "%c", &((*red)[i][j])); 
                fscanf(infile, "%c", &((*green)[i][j])); 
                fscanf(infile, "%c", &((*blue)[i][j])); 
            }
        }

	fclose(infile);
}

void outputppm(char * outfilename, char **red, char **green, char **blue)
{
	FILE * outfile;
	int i, j;
	
	if ((outfile = fopen(outfilename, "w")) == NULL)
	{
		printf("Couldn't open %s\n", outfilename);
		exit(0);
	}

	fprintf(outfile, "P6\n%d %d\n255\n", WIDTH, HEIGHT);

	for (j=0; j<HEIGHT; j++)
	{
	    if (!(j %100)) 
		printf("Writing line %d\n", j);
	    for (i=0; i<WIDTH; i++)
	    {
		fprintf(outfile, "%c", red[i][j]);
		fprintf(outfile, "%c", green[i][j]);
		fprintf(outfile, "%c", blue[i][j]);
	    }
	}

	fclose(outfile);
}

void outputshrunkenppm(char * outfilename, char **red, char **green, char **blue)
{
	FILE * outfile;
	int i, j;
	
	printf("Outfilename is %s\n", outfilename);
	
	if ((outfile = fopen(outfilename, "wb")) == NULL)
	{
		printf("Couldn't open %s\n", outfilename);
		exit(0);
	}

	fprintf(outfile, "P6\n%d %d\n255\n", SWIDTH, SHEIGHT);

	for (j=0; j < HEIGHT; j += SHRINKRATIO)
	{
	    if (!(j %100)) 
		printf("Writing line %d\n", j);

	    for (i=0; i < WIDTH; i += SHRINKRATIO)
	    {
		fprintf(outfile, "%c", red[i][j]);
		fprintf(outfile, "%c", green[i][j]);
		fprintf(outfile, "%c", blue[i][j]);
	    }
	}

	fclose(outfile);
}

void printargs(int argc, char * argv[])
{
	int i;

	for (i=0; i<argc; i++)
	{
		printf("%d: %s\n", i, argv[i]);
	}
}