DAT (Ever17)

Seen/used in the follow game(s):

• Ever17

Structure

Header
Size	Content	Description
4Bytes	Magic/ID
4Bytes	File Count
8Bytes	Padding	0x00
Index
Size	Content	Description
4Bytes	Offset	Starts from zero.
4Bytes	File Size	Stored value is actual size doubled
24Bytes	File name	Unused space will be padding (0x00).

Notes for 'wallpaper.dat'
The files inside this archive appear to have been processed before being put inside the archive. Every *.JPG file has a 256 byte chunk of data from offset 4352 to 4608 (base 10) that differs from the same file that is saved from the in-game wallpaper menu (special features). This effectively breaks/corrupts the picture. To fix this , you have to subtract each byte in the obstructed area by a specific number, which is different for each byte and for each picture. This array of difference numbers is calculate by first adding the filename's characters together by treating them as a 1 byte number, and truncate the number to just 8-bits/1 Byte. This is the first difference number of the 256 needed to be generated. The rest are generated using a series of calculations using the previously generated number.

'a' starts off as the value of the previous number.

Order	Expression
1	d = a + (a*2)
2	d = d + (d*8)
3	a = a+(d*4)+1243

unsigned char diff_array[256];

void diff_gen(std::string &incoming_filename)
{
	char firstValue = 0;
	for (unsigned int i = 0; i < incoming_filename.size(); i++) //Better be 14 bytes... Though adding 0x00 shouldn't affect output.
	{
		firstValue += incoming_filename[i];
	}

	diff_array[0] = firstValue;

	for (int i = 1; i < 255; i++)
	{
		char temp = diff_array[i - 1] + (diff_array[i - 1] * 2);
		temp = temp + (temp * 8);
		diff_array[i] = diff_array[i - 1] + (temp * 4) + 1243;
	}
}

Current task-> Rewrite archive tool for packing and unpacking. Fix flaws in wallpaper fix tool. Also think about renamming wallpaper fix tool if other files extracted show same thing, such as scripts.

Why do I have to be so OCD...? >.< First it's 'arctool', then 'dattool'... datTool? :T