File identification

Things like the average size of a polygon, the number of polygons, the number of items, the creation date are (imho) sure-fire ways. Two maps never look the same from that point of view.

I want to be sure the map files are the same. It''s possible to have the same number of polys, or faces in a map, but maps are totally differents...

- Iliak -

I''d store a UUID/GUID or similar in the header of the file when it''s created - in practical circumstances you can trust those to always be unique.

Then all you need to do is compare the headers for the two files rather than computing full CRCs for the whole file.

For a little extra data integrity/security you could also compute the CRC of just the header to ensure it (and therefore the UUID) hasn''t become corrupt.

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Simon O''Connor
Game Programmer &
Microsoft DirectX MVP

I don''t know if MD5 is a better choice. I know it''s harder to fake the correct MD5, but don''t know if it would be too much computation for what you want.

I downloaded a md5 algo by John Walker @ http://www.fourmilab.ch/ and it takes me 600ms to checksum'izing a 15Mo file...

It sounds great...

- Iliak -

[edited by - iliak on May 17, 2004 11:43:42 AM]