pixiv_downloader/doc/pd_file_spec.md

The spec for .pd file

Numbers are encoded in little endian.

Fixed size part

Offset	Size	Name	Type	Description
0	4	magic_word	Bytes	Should always be 5044FFFF
4	2	version	Bytes	Version number, the first byte is major version, the second byte is minor version
6	4	file_name_len	u32	The size of the file name
10	1	status	Enum(u8)	The status of the downloaded file.
11	1	type	Enum(u8)	The type of the downloader.
12	8	file_size	u64	The target size of the file. If unknown, set this to 0.
20	8	downloaded_file_size	u64	The size of the downloaded data.
28	4	part_size	u32	The size of the each part. Ignored in single thread mode.

Non-fixed size part

Size	Name	Type	Description
file_name_len	file_name	String	The file name encoded in UTF-8.
-	part_datas	Bytes	The status of the each part. Ignored in single thread mode.

Part status

Offset(Bit)	Size(Bit)	Name	Type	Description
0	2	status	Enum(u8)	The current status of this part.
2	30	downloaded_size	u32	The size of the downloaded data in this part.

Enum

status

Number	Name	Description
0	started	The download is already started but the target size is unknown.
1	downloading	The download is started and the tagret size is known.
2	downloaded	The download is completed.

type

Number	Name	Description
0	single_thread	Download in single thread mode.
1	multi_thread	Download in multiple thread mode.

part status

Number	Name	Description
0	waited	The download of this part is waited.
1	downloading	The download of this part is started.
2	downloaded	The download of this part is completed.