#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include <ctype.h>
#include <conio.h>
void CloseF();
void CodingText();
void HeaderInf();
int LogicScreen();
void Coding();
void Decoding();
void Copyring();

FILE *InF, *OutF, *TextF;
int numbyteIn=0,numbyteOut=0,numbyteText=0,power=3,size;
char what,type[3];
char InName[250],OutName[250],TextName[250];
///////////////////////*Openning files*//////////////////////
int main (void)
{
int count=-1,j;
char ch;

puts("Coding / Decoding");
while(count==-1){
	what = getchar();
	what = toupper(what);
	switch (what) {
		case 'C': what=1; count=1; break;
		case 'D': what=0; count=1; break;
		default: continue;}
		}
puts("Write name of start picture file");
gets(InName);
gets(InName);
if(what) {
	puts("Write name of end picture file");
	gets(OutName);
	puts("Write name of text file");
	gets(TextName);}

if((InF = fopen(InName, "rb")) == NULL){
	printf("File '%s' not found\n", InName);
	getchar();
	CloseF(InF,OutF,TextF);}
if(what){
	if((OutF = fopen(OutName, "wb+")) == NULL){
		printf("Oshibka sozdania fila '%s'\n", OutName);
		CloseF(InF,OutF,TextF);
		return 0;}
	if((TextF = fopen(TextName, "rb")) == NULL){
		printf("File '%s' not found\n", TextName);
		CloseF(InF,OutF,TextF);;
		return 0;}

	printf("Insert type of file for coding: ");
	gets(type);

	what = 1;
}
else{
	puts("Write name of end file without type"); j=0;
	gets(TextName);
	/*while(TextName[j]!='.'){
		ch = TextName[j++] = getch();
		puts(ch);}*/}
printf("Insert pow of coding  1 bit on byte or 2 bits on byte: ");
	count=-1;
	while(count!=1){
		count = getchar();
		switch (count) {
			case '1': power = 1; count = 1; break;
			case '2': power = 2; count = 1; break;
			default: count = -1; continue;}
			}
HeaderInf(InF,OutF,TextF);
count = LogicScreen(InF);
if (what) Coding(InF,OutF,TextF,count);
else Decoding(OutF,TextF,count);
CloseF(InF,OutF,TextF);
return 0;
}
///////////////////////*Closing Files*///////////////////////
void CloseF(FILE *InF, FILE *OutF, FILE *TextF)
{
	fclose(InF);
	if(what) fclose(OutF);
	fclose(TextF);
	puts("Operacia vipolnena");
	getch();
	exit (0);
}
/////////////////*Scanning for Signature*////////////////////
void HeaderInf(FILE *InF, FILE *OutF, FILE *TextF)
{
int gifbyte;
	char Signature[3]="GIF";
	char Version1[3]="87a";
	char Version2[3]="89a";

fseek(InF,numbyteIn,SEEK_SET);
//Closing programm if file not GIF 87a or 89a
for(numbyteIn=0; numbyteIn<3; numbyteIn++)
	if((gifbyte = fgetc(InF))!= Signature[numbyteIn])
	{
	puts("This file hasn't GIF format");
	CloseF(InF,OutF,TextF);
	}
for(numbyteIn=0; numbyteIn<3; numbyteIn++){
	gifbyte = fgetc(InF);
	if(gifbyte == Version1[numbyteIn] || Version2[numbyteIn]) continue;
	else{
		puts("This file hasn't GIF format");
		CloseF(InF,OutF,TextF);}
	}
numbyteIn=ftell(InF);
return;
}
/////////////////////*Logigic Screen*////////////////////////
int LogicScreen(FILE *InF)
{
int i,count=0;
unsigned int mask[8]={128,64,32,16,8,4,2,1};
	int wight=0, height=0, PackedFields, Background;
	double PixelAspectRatio;

fseek(InF,numbyteIn,SEEK_SET);
wight = fgetc(InF); //printf("%i ", wight);
if(!wight){
	wight = fgetc(InF);// printf("%i ", wight);
}
numbyteIn+=2;
fseek(InF,numbyteIn,SEEK_SET);

height = fgetc(InF); //printf("%i ", height);
if(!wight){
	height = fgetc(InF); //printf("%i ", height);
}
numbyteIn+=2;
fseek(InF,numbyteIn,SEEK_SET);

PackedFields = fgetc(InF);  //printf("%i", PackedFields);
Background = fgetc(InF); //printf("%i", Background );
PixelAspectRatio = fgetc(InF); //printf("%f", PixelAspectRatio );
//printf("Size of your picture is %i x %i\n", wight,height);
numbyteIn = ftell(InF);
if((PackedFields & mask[0]) == mask[0]) puts("Global Color Table is using");
else puts("Global Color Table isn't using");
for(i=1; i<4;i++)
	if((PackedFields & mask[i]) == mask[i])
		count += mask[i];
//printf("Number of bits on colors dpi %i\n", count-1);
count=0;
if((PackedFields & mask[4]) == mask[4]) puts("Global Color Table is sorting");
else puts("Global Color Table isn't sorting");
for(i=5; i<8; i++)
	if((PackedFields & mask[i]) == mask[i]) 
		count += mask[i];
count = (int)pow(2,count+1);
printf("Number colors on byte %i\n", count);
if(!PixelAspectRatio) PixelAspectRatio = 1;
PixelAspectRatio += 15;
PixelAspectRatio /= 64;
printf("Attitutde widht pixel to his height is %.2f\n", PixelAspectRatio);
return 3*count;
}
/////////////////*Coding text into picture*//////////////////
void Coding(FILE *InF, FILE *OutF, FILE *TextF, int count)
{
char bufer[8],massiv[8];
int ch,i,j=0,byte,k,m;
unsigned char mask[4]={254,253,1,2};

if(what){
	fseek(TextF,numbyteText,SEEK_SET);
	ch = fgetc(TextF);
	while(ch != EOF){
		ch = fgetc(TextF);
		size++;}
	printf("Size of text file - %i\n", size);
	ch=32;
	if(size/power > 92){
		puts("This file couldn't coding in this picture! Operation has been breaked.");
		getch();
		CloseF(InF,OutF,TextF);}
	numbyteText = 0;
}

fseek(TextF,numbyteText,SEEK_SET);
if(numbyteOut < numbyteIn){
fseek(InF,0,SEEK_SET);
fseek(OutF,numbyteOut,SEEK_SET);
while(numbyteOut < numbyteIn){
	byte = fgetc(InF);
	fputc(byte,OutF);
	numbyteOut++;}}

while(j<4){
	if(j == 3) ch = (int)size;
	else ch = type[j];
for(i=7; i>=0; i--){
		bufer[i] = ch % 2;
		ch /= 2;}
	m = 0;
	for(i=0; i<8/power; i++){
		ch = byte = fgetc(InF);
		for(k=power; k>0; k--){ 

			ch = bufer[m];
			bufer[m++] = 0;
			if(ch == 0){
				if(k == 1) byte = byte & mask[0];
				else byte = byte & mask[1];}		
			else{
				if(k == 1) byte = byte | mask[2];
				else byte = byte | mask[3];}					
			}
		fputc(byte,OutF);
		}
count--;
j++;}

while(count>0){
	if((ch = fgetc(TextF)) == EOF) break;
	for(i=7; i>=0; i--){
		bufer[i] = ch % 2;
		ch /= 2;}
	m = 0;
	for(i=0; i<8/power; i++){
		ch = byte = fgetc(InF);
		for(k=power; k>0; k--){ 

			ch = bufer[m];
			bufer[m++] = 0;
			if(ch == 0){
				if(k == 1) byte = byte & mask[0];
				else byte = byte & mask[1];}		
			else{
				if(k == 1) byte = byte | mask[2];
				else byte = byte | mask[3];}				
			}
		fputc(byte,OutF);
		}
count--;}
	
numbyteIn = ftell(InF);
numbyteOut = ftell(OutF);
numbyteText = ftell(TextF);
Copyring(InF,OutF,TextF);
return;
}
/////////////////*Decoding from picture*////////////////////////
void Decoding(FILE *OutF, FILE *TextF, int count)
{
int bufer[8];
int i,j,byte,g=0;
unsigned char mask[2]={2,1};
size=256;

fseek(InF,numbyteIn,SEEK_SET);
while(count>0){
	if(power == 2){
		for(i=0; i<8; ){
				byte = getc(InF);
				bufer[i++] = (byte & mask[0])/2;
				bufer[i++] = byte & mask[1];}
		byte = 0;
		j=7;count--;
		for(i=0; i<8; i++){
				byte += bufer[i] * (int)pow(2,j);
				j--;}
		}
	if(power == 1){
		for(i=0; i<8; i++){
				byte = getc(InF);
				bufer[i] = byte & mask[1];}
		byte = 0;
		j=7;count--;
		for(i=0; i<8; i++){
				byte += bufer[i] * (int)pow(2,j);
				j--;}
		}
	if(g == 3 || g == 5) g++;
	if(g < 3){
		type[g] = byte; 
		g++;}
	if(g == 4){		
		g = 0;
		size = byte; 
		//count = 0;
		printf("type of file - %s, size of file - %i\n", type,size);
		/*g = strlen(TextName);
		for(i=0; i<3; i++)
			TextName[g++] = type[i];*/

		if((TextF = fopen(TextName, "wb+")) == NULL && what){
			printf("Oshibka sozdania fila '%s'\n", OutName);
			getchar();
			CloseF(InF,OutF,TextF);}
		fseek(TextF,numbyteText,SEEK_SET);
		g = 5;}
	if(g>5){	
		fputc(byte,TextF);
	//	count++;
	}
	}
numbyteText = ftell(TextF);
numbyteIn = ftell(InF);
CloseF(InF,OutF,TextF);
return;
}
//////////////*copering*/////////////////////////////
void Copyring(FILE *InF, FILE *OutF, FILE *TextF)
{
int byte;
fseek(InF,numbyteIn,SEEK_SET);
while((byte=fgetc(InF)) != EOF){ 
	fputc(byte,OutF);}
CloseF(InF,OutF,TextF);
return;
}