Difference between revisions of "DAT (Ever17)"

Latest revision as of 23:19, 5 October 2016

Used in the following game(s):

Ever17 (PC)

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 double the actual size
24Bytes	File name	Unused space will be padding (0x00).

Notes

The files inside saver.dat, sysvoice.dat, and wallpaper.dat for Ever17 have had a small chunk data obfuscated. From offset 0x1100 to 0x1200 (256 bytes), data has been modified which breaks/corrupts the file. To undo this modification requires generating numbers to subtract from each byte in the affected area.

To generate these numbers, start off by adding each character in the file name of the file in question together, byte-by-byte. For example: 'test' 0x74 0x65 0x73 0x74 = 0x1C0 and then truncate the number down to 1 byte so 0xC0. This would be the first difference number out of the 256. The rest of the numbers are generated by using the previous number in a series of calculations.

1.) temp = previousNum + (previousNum * 2)
2.) temp = temp + (temp * 8)
3.) nextNum = previousNum + (temp * 4) + 1243

Note: This can probably be optimized to one statement to make it more readable.

y = x + (((x + (x * 2)) + (x + (x * 2) * 8))* 4) + 1243

y = 81x + 1243

nextNum = (81 * previousNum) + 1243;

A C++ representation.

unsigned char diff_array[256];

void diff_gen(std::string &incoming_filename)
{
	char firstValue = 0;
	for (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++)
	{
                diff_array[i] = diff_array[i - 1] * 81 + 1243;
	}
}

Tools

-n/a-

@@ Line 1: / Line 1: @@
 [[Category:Archives]]
+Used in the following game(s):
-Seen/used in the follow game(s):
+* Ever17 (PC)
-* Ever17
 == Structure ==
@@ Line 22: / Line 21: @@
 | 4Bytes || Offset || Starts from zero.
 |-
-| 4Bytes|| File Size || Stored value is actual size doubled
+| 4Bytes|| File Size || Stored value is double the actual size
 |-
 | 24Bytes|| File name || Unused space will be padding (0x00).
 |}
-Notes for 'wallpaper.dat'<br />
+== Notes ==
-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 (think base 16/hexadecimal), 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.
+The files inside saver.dat, sysvoice.dat, and wallpaper.dat for Ever17 have had a small chunk data obfuscated. From offset 0x1100 to 0x1200 (256 bytes), data has been modified which breaks/corrupts the file. To undo this modification requires generating numbers to subtract from each byte in the affected area.
+To generate these numbers, start off by adding each character in the file name of the file in question together, byte-by-byte. For example: 'test' 0x74 0x65 0x73 0x74 = 0x1C0 and then truncate the number down to 1 byte so 0xC0. This would be the first difference number out of the 256. The rest of the numbers are generated by using the previous number in a series of calculations.
+* 1.) temp = previousNum + (previousNum * 2)
+* 2.) temp = temp + (temp * 8)
+* 3.) nextNum = previousNum + (temp * 4) + 1243
+Note: This can probably be optimized to one statement to make it more readable.
+y = x + (((x + (x * 2)) + (x + (x * 2) * 8))* 4) + 1243
+y = 81x + 1243
+nextNum = (81 * previousNum) + 1243;
+A C++ representation.
+<syntaxhighlight lang="cpp">
+unsigned char diff_array[256];
-'a' starts off as the value of the previous number.
+void diff_gen(std::string &incoming_filename)
-{| class="wikitable"
+{
-|-
+	char firstValue = 0;
-! Order !! Expression
+	for (int i = 0; i < incoming_filename.size(); i++) //Better be 14 bytes... Though adding 0x00 shouldn't affect output.
-|-
+	{
-| 1|| d = a + (a*2)
+		firstValue += incoming_filename[i];
-|-
+	}
-| 2 || d = d + (d*8)
-|-
-| 3|| a = a+(d*4)+1243
-|}
-Yay for dissemblers and debuggers! :P
+	diff_array[0] = firstValue;
-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.
+	for (int i = 1; i < 255; i++)
+	{
+                diff_array[i] = diff_array[i - 1] * 81 + 1243;
+	}
+}
+</syntaxhighlight>
-Why do I have to be so OCD...? >.< First it's 'arctool', then 'dattool'... datTool? :T
+== Tools ==
+-n/a-

Difference between revisions of "DAT (Ever17)"

Latest revision as of 23:19, 5 October 2016

Structure

Notes

Tools

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