File Synchro (Checksum, Fragments, ...)

  • Thread starter Thread starter Cybertof
  • Start date Start date
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Cybertof

Hello,

What would be the best way to synchronise 2 big files ?

The files have only small modifications (not more than 10Kb changed /
added insided).
It would a bad choice to transfer 5Mb regarding only 10Kb of changes.
If only a few bytes are added/modified it's does not worth it to
transfer the whole file.

The idea would be the following one :
Make a dichotomy to find out only modified fragments and only transfer
changes (extending the file length if necessary).
Client and Server would only exchange checksums and only transfer
fragments of the files that differ.

Would you have hints ?
- Checksum algorythms
- Transfer by fragment
- OpenSource Projects
- Samples
- Ideas


Thanks.

Cybertof.
 
Cybertof said:
What would be the best way to synchronise 2 big files ?

The files have only small modifications (not more than 10Kb changed /
added insided).
It would a bad choice to transfer 5Mb regarding only 10Kb of changes.
If only a few bytes are added/modified it's does not worth it to
transfer the whole file.

The idea would be the following one :
Make a dichotomy to find out only modified fragments and only transfer
changes (extending the file length if necessary).
Client and Server would only exchange checksums and only transfer
fragments of the files that differ.

Would you have hints ?
- Checksum algorythms
- Transfer by fragment
- OpenSource Projects
- Samples
- Ideas
Click to expand...

There's a good binary diff file format called vcdiff. I've got a
decoder that you're welcome to use at
http://www.pobox.com/~skeet/csharp/miscutil

However, it doesn't have an encoder - you can use one called xdelta3
though, which is freely available (but not in .NET).
 
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