SARC (File Format)

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SARC Files are archive files used in Wii U and 3DS, including Mario Kart 8. They are similar to the U8 files found in GameCube and Wii games. Common extensions are .arc and .sarc (general), .pack (when the archive contains mostly other archive files), .bars (when it contains audio data), and .bgenv (when it contains shader files). SARC files are sometimes Yaz0 compressed into .szs files.

File Format

The basic structure of the archive is a SARC Header followed by a File Table and a File Name Table. Finally, the content of all files in the archive is stored directly. The File Table references the data.

Header (SARC)

Every SARC archive beings with a 0x14 byte SARC Header structure.

Offset Size Description
0x00 4 Magic: 0x53415243 ("SARC" in ASCII).
0x04 2 Header Length: the length of this header in bytes. Always 0x14.
0x06 2 Byte order mark (BOM): 0xFE,0xFF for big endian and 0xFF,0xFE for little endian.
0x08 4 File size of the entire archive in bytes.
0x0c 4 Beginning of data offset.
0x10 4 Unknown. Always 0x01000000?
0x14 End of SARC header

File Table

Unlike the U8 format, SARC does generally not contain directory nodes (though files may reside inside subfolders). It is currently unknown if it is able to.

Header (SFAT)

The SARC Header is immediately followed by 0xc byte SFAT Header structure.

Offset Type Description
0x00 4 Magic: 0x53464154 ("SFAT").
0x04 2 Header Length: the length of this header in bytes. Always 0xc.
0x06 2 Node count.
0x08 4 Hash Multiplier. Always 0x00000065.
0x0c End of SFAT header

Node

The SFAT Header is followed by an array of 0x10 byte SFAT Node structures.

Offset Size Description
0x00 4 File Name Hash. Look below for the calculation.
0x04 1 0x00 for archives without any file name stored, 0x01 for archives with file names stored.
0x05 3 File name table entry offset, relative to the end of the file name table header, divided by 4.
0x08 4 Beginning of node file data, relative to the Beginning of data offset specified in the SARC header.
0x0c 4 End of node file data, relative to the Beginning of data offset specified in the SARC header.
0x10 End of node

File Name Hash

The hash is calculated like this:

uint GetHash(char* name, int length, uint multiplier)
{
	uint result = 0;
	for(int i = 0; i < length; i++)
	{
		result = name[i] + result * multiplier;
	}
	return result;
}

File Name Table

The File Name Table is a list of null-terminated strings which represent the filenames of the packed files. It is referenced by SFAT Nodes.

Header (SFNT)

The SFAT Node array is immediately followed by an 0x8 byte SFNT Header structure.

Offset Size Description
0x00 4 Magic: 0x53464E54 ("SFNT").
0x04 2 Header Length: the length of this header in bytes. Always 0x8.
0x06 2 Unknown. Always 0?
0x08 End of SFNT header

Strings

The SFAT Header is immediately followed by 4-byte aligned null-terminated strings that represent the filenames of the packed files.

File Data

The data begins at the Beginning of data offset specified in the SARC Header. There is padding between the files for 256-byte (0x100) alignment.

Tools

The following tools can handle SARC files: