The Finder info of AppleDouble and AppleSingle files

Entry 9 holds the 32 bytes the Finder keeps about a file: an FInfo record followed by an FXInfo record, both big-endian. macOS writes a longer entry and keeps the file’s extended attributes after these 32 bytes.

FInfo

Offset	Size	Field	Meaning
0	4	File type	Four characters, such as `TEXT` or `APPL`
4	4	Creator	Four characters, the signature of the application that made the file
8	2	Finder flags	See below
10	2	Location v	Signed: the vertical position of the icon in its window
12	2	Location h	Signed: the horizontal position; both 0 lets the Finder place it
14	2	Folder	Used only under the flat MFS file system, where Inside Macintosh gives −3 for a file in the Trash. Unused and zero on HFS disks and later

FXInfo

Offset	Size	Field	Meaning
16	2	Icon ID	The ID of the file’s icon, assigned by the Finder
18	6	Reserved	Unused
24	2	Extended flags	One 16-bit field: see below
26	2	Comment ID	Signed: the ID of the Get Info comment, assigned by the Finder. Only a comment ID while the top bit is clear
28	4	Put-away folder	Signed: the directory ID a file moved to the desktop returns to

Finder flags

Mask	Name	Meaning
`8000`	Alias	The file is an alias
`4000`	Invisible	The Finder does not show the file
`2000`	Has bundle	The file has a `BNDL` resource, or a folder displays as a package
`1000`	Name locked	The Finder may not rename it
`0800`	Stationery	The file is a stationery pad
`0400`	Custom icon	The file has a custom icon
`0200`	Reserved	Once AOCE’s letter bit
`0100`	Inited	The Finder has loaded the file’s bundle resources into its database
`0080`	No INITs	The file holds no `INIT` resource
`0040`	Shared	An application that can be used by several users at once
`0020`	Reserved	Once switch-launch
`0010`	Reserved
`000E`	Colour label	Bits 1 to 3: see below
`0001`	On desktop	On the desktop (System 6, HFS)

The colour label

Bits 1 to 3 hold a number from 0 to 7. Modern Finders show them as these colours; what the number means in older systems was up to the user’s label settings.

Value	Finder colour
0	None
1	Grey
2	Green
3	Purple
4	Blue
5	Yellow
6	Red
7	Orange

Extended flags and the script code

Bytes 24 and 25 are read as a single 16-bit field. Bit 15 decides what the rest means. Apple’s older FXInfo definition names byte 24 fdScript and byte 25 fdXFlags; its later ExtendedFileInfo treats the two as one word, extendedFinderFlags.

When bit 15 is set, the other extended flags are not valid, and the low 7 bits of byte 24 are the script code the name is written in.
When bit 15 is clear, the Finder uses the system script, and the flags below apply.

Mask	Name	Meaning
`8000`	Invalid	The other extended flags are to be ignored; the top byte’s low 7 bits are a script code
`0100`	Custom badge	The file or folder has a badge resource
`0080`	Busy	The object is marked as busy or incomplete
`0004`	Routing info	The file has a routing info resource

Script codes

Code	Script	Code	Script
0	Roman	17	Malayalam
1	Japanese	18	Sinhalese
2	Traditional Chinese	19	Burmese
3	Korean	20	Khmer
4	Arabic	21	Thai
5	Hebrew	22	Lao
6	Greek	23	Georgian
7	Cyrillic	24	Armenian
8	Right-to-left symbols	25	Simplified Chinese
9	Devanagari	26	Tibetan
10	Gurmukhi	27	Mongolian
11	Gujarati	28	Ethiopic
12	Oriya	29	Central European Roman
13	Bengali	30	Vietnamese
14	Tamil	31	Extended Arabic
15	Telugu	32	Uninterpreted symbols
16	Kannada

Folders

For a folder the same 32 bytes hold a DInfo and DXInfo instead: the window’s rectangle (top, left, bottom, right), Finder flags, location and view, then the scroll position, the open chain, the same extended flags, the comment ID and the put-away folder. An AppleDouble file does not say whether the file it describes is a file or a folder.

._ File Format – Finder info