@Lord-Spectre (View Post)
They're both the same, it's just that stamps have a variable width/height
Format is:
Magic number (3 Bytes):
'PSv'
Saved settings (1 Byte):
Bit 0: Legacy mode
Bit 1: Pause mode
Bit 2-3: Gravity mode
Bit 4-6: Air mode
Bit 7: Newtonian gravity mode
Game version (1 Byte)
Cell size (1 Byte)
Width, in cells (1 Bytes)
Heigth, in cells (1 Bytes)
Unzipped size of the save data (4 Bytes)
Save data, zipped with bzip2:

All walls (1 Byte each)
For FANs: X speed (1 Byte each)
For FANs: Y speed (1 Byte each)
All particles, types (1 Byte each)
Particles X speed (1 Byte each)
Particles Y speed (1 Byte each)
Particles life (2 Byte each)
Particles tmp (2 Byte each)
Particles deco alpha (1 Byte each)
Particles deco red (1 Byte each)
Particles deco green (1 Byte each)
Particles deco blue (1 Byte each)
Particles temperature (2 Byte each)
Particles ctype, only for CLNE, PCLN, BCLN, SPRK, LAVA & PIPE (1 Byte each)
Number of signs (1 Byte)
Then for each sign:

X position (2 Bytes)
Y position (2 Bytes)
Text align (1 Byte)
Length of text (1 Byte)
Text (IV Bytes)

EOF(End of File)
Thank you, JoJoBond.

This is the saving function, http://pastebin.com/wCsHL7zK
The compressing function is
BZ2_bzBuffToBuffCompress((char *)(c+12), (unsigned *)&i, (char *)d, p, 9, 0, 0)
To decompress it, just run
BZ2_bzBuffToBuffDecompress(arguments);