#include <stdio.h> 
#include <stdlib.h> 
 
const int  PARAMS_NUM = 4; 
const int  GRILL_SIZE = 12; 
const char HOLE 	  = 'X'; 
 
FILE *open_file(const char *filename, const char *access); 
 
void read_matrix(const char *filename, char matrix[][GRILL_SIZE], int size); 
 
enum GRILL_TYPE {GRILL_NOT_LEGAL = 0 , GRILL_LEGAL = 1}; 
GRILL_TYPE grill_legal(char grill[][GRILL_SIZE], int size); 
 
void decrypt(char output[], const char encrypted[][GRILL_SIZE], 
			 char grill[][GRILL_SIZE], int size); 
 
void turn_grill(char grill[GRILL_SIZE][GRILL_SIZE]); 
 
void write_output(const char *filename, char output[], int size); 
 
 
 
int main(int argc, char *argv[]) 
{ 
	if(argc != PARAMS_NUM) 
	{ 
		fprintf(stderr,"Invalid number of parameters, usage : grill <encrypted> <grill> <output>\n"); 
		exit(-1); 
	} 
 
	char encrypted[GRILL_SIZE][GRILL_SIZE]; 
	char grill[GRILL_SIZE][GRILL_SIZE]; 
	char plain[GRILL_SIZE*GRILL_SIZE]; 
 
	read_matrix(argv[1], encrypted, GRILL_SIZE); 
	read_matrix(argv[2], grill, GRILL_SIZE); 
 
	if( grill_legal(grill, GRILL_SIZE) == GRILL_NOT_LEGAL) 
	{ 
		fprintf(stderr, "Illegal grid inserted !!!\n"); 
		exit(1); 
	} 
 
	decrypt(plain, encrypted, grill, GRILL_SIZE); 
 
	write_output(argv[3], plain, GRILL_SIZE*GRILL_SIZE); 
 
	return 0; 
} 
 
FILE *open_file(const char *filename, const char *access) 
{ 
	FILE *file_handle; 
 
	file_handle = fopen(filename, access); 
	if(file_handle == NULL) 
	{ 
		fprintf(stderr,"Unable to open file %s\n", filename); 
		exit(-1); 
	} 
 
	return file_handle; 
} 
 
void read_matrix(const char *filename, char matrix[][GRILL_SIZE], int size) 
{ 
	FILE *file_handle = open_file(filename, "r"); 
 
	for(int i = 0; i < size ; i++) 
	{ 
		for(int j = 0 ; j < size ; j++) 
		{ 
			matrix[i][j] = fgetc(file_handle); 
		} 
 
		fgetc(file_handle);			// The newline character 
	} 
 
	fclose(file_handle); 
} 
 
GRILL_TYPE grill_legal(char grill[][GRILL_SIZE], int size) 
{ 
	for(int i = 0 ; i < size ; i++) 
	{ 
	   for(int j = 0 ; j < size ; j++) 
	   { 
		  if( (grill[i][j] == HOLE) && 
			  ( (grill[j][size - 1 - i] == HOLE) || 
				(grill[size - 1 - i][size - 1 - j] == HOLE) || 
				(grill[size - 1 - j][i] == HOLE))) 
		  { 
			 return GRILL_NOT_LEGAL; 
		  } 
	   } 
	} 
 
	return GRILL_LEGAL; 
} 
 
void decrypt(char output[], const char encrypted[][GRILL_SIZE], 
			 char grill[][GRILL_SIZE], int size) 
{ 
	int output_cnt = 0; 
 
	for(int turns = 0 ; turns < 4 ; turns++) 
	{ 
		for(int i = 0 ; i < size ; i++) 
		{ 
			for(int j = 0 ; j < size ; j++) 
			{ 
				if(grill[i][j] == HOLE) 
					output[output_cnt++] = encrypted[i][j]; 
			} 
		} 
 
		turn_grill(grill); 
	} 
} 
 
void turn_grill(char grill[GRILL_SIZE][GRILL_SIZE]) 
{ 
	char temp[GRILL_SIZE][GRILL_SIZE]; 
 
	for(int i = 0 ; i < GRILL_SIZE ; i++) 
	{ 
		for(int j = 0 ; j < GRILL_SIZE ; j++) 
		{ 
			temp[j][(GRILL_SIZE - 1) - i] = grill[i][j]; 
		} 
	} 
 
	for(i = 0 ; i < GRILL_SIZE ; i++) 
	{ 
		for(int j = 0 ; j < GRILL_SIZE ; j++) 
		{ 
			grill[i][j] = temp[i][j]; 
		} 
	} 
} 
 
void write_output(const char *filename, char output[], int size) 
{ 
	FILE *file_handle = open_file(filename, "w"); 
 
	for(int i = 0 ; i < size ; i++) 
	{ 
		fputc(output[i], file_handle); 
	} 
 
	fclose(file_handle); 
}