This is the compression format used for each file in EDF2017.
It is basically the same as CMPL Compression, with some differences in the initial position of the buffer and the method of copying to the buffer.

Offset	Size	Description
0x00	4	"SGSL" header
0x04	4	original file size(Little Endian)
0x08	-	compressed contents

1. The initial position of the buffer is set to 3823.
   
2. Read/write to buffer is done in 16-byte skips.
   
3. If the read/write destination is a value greater than 4096,
   (a)If the value is 4096-4110, the value minus 4095 is the next read/write destination.
   (b)If the value is 4111 (i.e.,the previous is 4095), then 0 is the next read/write destination.