#include <stdio.h>
int x;
int nrcitiri;


void merge(char* source_file1, char* source_file2, char* destination_file1, char* destination_file2, int size, int* repeat)
{
	int i, j;
	int x; // aici trebuie folosit un element de tipul elementelor din fisier
	int y; // aici trebuie folosit un element de tipul elementelor din fisier
	int eof1, eof2;
	FILE* source1;
	FILE* source2;
	FILE* destination1;
	FILE* destination2;
	FILE* destination;
	source1 = fopen(source_file1, "rb");
	if (!source1)
	{
		printf("ERROR! File not available\n");
		return;
	}
	source2 = fopen(source_file2, "rb");
	if (!source2)
	{
		printf("ERROR! File not available\n");
		return;
	}
	destination1 = fopen(destination_file1, "wb");
	destination2 = fopen(destination_file2, "wb");
	eof1 = feof(source1);
	eof2 = feof(source2);
	if (!eof1)
	if (fread(&x, sizeof(int), 1, source1) < 1)
		eof1 = 1;
	if (!eof2)
	if (fread(&y, sizeof(int), 1, source2) < 1)
		eof2 = 1;
	destination = destination1;
	do
	{
		i = 0;
		j = 0;
		while (i < size && j < size && !eof1 && !eof2)
		{
			if (x > y)
			{
				fwrite(&x, sizeof(int), 1, destination);
				i++;
				if (feof(source1))
					eof1 = 1;
				else if (fread(&x, sizeof(int), 1, source1) < 1)
					eof1 = 1;
			}
			else
			{
				fwrite(&y, sizeof(int), 1, destination);
				j++;
				if (feof(source2))
					eof2 = 1;
				else if (fread(&y, sizeof(int), 1, source2) < 1)
					eof2 = 1;
			}
		}
		while (i < size && !eof1)
		{
			fwrite(&x, sizeof(int), 1, destination);
			i++;
			if (feof(source1))
				eof1 = 1;
			else if (fread(&x, sizeof(int), 1, source1) < 1)
				eof1 = 1;
		}
		while (j < size && !eof2)
		{
			fwrite(&y, sizeof(int), 1, destination);
			j++;
			if (feof(source2))
				eof2 = 1;
			else if (fread(&y, sizeof(int), 1, source2) < 1)
				eof2 = 1;
		}
		if (destination == destination1)
			destination = destination2;
		else
			destination = destination1;
		if (!eof1 || !eof2)
			*repeat = 1;
	} while (!eof1 || !eof2);
	fclose(source1);
	fclose(source2);
	fclose(destination1);
	fclose(destination2);
}
char* four_way_sequence_merging(char* file_name, char* auxiliary1, char* auxiliary2, char* auxiliary3)
{
	FILE* source;
	FILE* destination1;
	FILE* destination2;
	int i, direction;
	int x; // aici trebuie folosit un element de tipul elementelor din fisier
	int size;
	int repeat;
	source = fopen(file_name, "rb");
	if (!source)
	{
		printf("ERROR! File not available\n");
		return NULL;
	}
	destination1 = fopen(auxiliary1, "wb");
	destination2 = fopen(auxiliary2, "wb");
	i = 0;
	while (!feof(source))
	{
		if (fread(&x, sizeof(int), 1, source) < 1)
			break;
		if (i % 2 == 0)
			fwrite(&x, sizeof(int), 1, destination1);
		else
			fwrite(&x, sizeof(int), 1, destination2);
		i++;
		nrcitiri++;
	}
	fclose(source);
	fclose(destination1);
	fclose(destination2);
	direction = 1;
	size = 1;
	do
	{
		repeat = 0;
		if (direction == 1)
			merge(auxiliary1, auxiliary2, file_name, auxiliary3, size, &repeat);
		else
			merge(file_name, auxiliary3, auxiliary1, auxiliary2, size, &repeat);
		size = size * 2;
		direction = -direction;
	} while (repeat != 0);
	if (direction == -1)
		return file_name;
	else
		return auxiliary1;
}
int main(void){
	FILE *fis = fopen("fis2.bin","wb");
	FILE *o = fopen("data2.bin", "rb");
	while (!feof(o)){

		fread(&x, sizeof(int), 1, o);
		fwrite(&x, sizeof(int), 1, fis);
	}
	four_way_sequence_merging("fis2.bin", "a1.bin", "a2.bin", "a3.bin");
	printf("nr operatii %d\n", nrcitiri);
	fclose(o);
	fclose(fis);
	FILE *fis2 = fopen("fis2.bin", "rb");
	FILE *txt = fopen("out.txt", "w");
	char c;
	while (!feof(fis2)){
		fread(&c, sizeof(char), 1, o);
		fprintf(txt,"%c",c);
	}

	fclose(fis2);
	fclose(txt);
	return 0;
}