How to turn a PDF document upside down

Question

Possible Duplicate:
How to save rotated Adobe pdf file?

I'd like to rotate by 180 degrees each page in a high-resolution .pdf, but don't know how. In ImageMagick, using 'convert -flip -flop' lowers the resolution significantly, while increasing the file size slightly. This also happens (to a lesser extent) in LibreOffice, an example of open-source PDF editors. Any ideas, besides buying Adobe Acrobat? (which may or may not solve the problem!)

Answer 1

PDF Split and Merge (pdfsam) has a processing option to rotate PDFs.

http://www.pdfsam.org/?page_id=10

Answer 2

The free PDFill PDF Tools can rotate the pdf, entirely or selectively, as well as doing many other useful operations on PDFs.