On Jan 20, 2011, at 2:48 , julius-schorzman wrote:
My question is -- can anything be done to retrieve part of the file?
It would be nice to know at which point in the file the problematic
message occurred, and then I could crop to that point or do some
manual exception -- but unfortunately this exception is very general.
I find it hard to believe that a single mis-saved bit makes the whole
file worthless.

You are correct: your entire data is not worthless, but at the point of the error, you will need some manual intervention to figure out what is going on.

It is probably possible to figure out the byte offset where this error occurs. The CodedInputStream tracks some sort of bytesRead counter, I seem to recall. However, this will require you to modify the source.

I also find it curious that the source provides no way (that I can
tell) to get at any lower level data in the p.b. since whenever I try
to do anything with it it throws an exception.  Best I can tell I will
have to write from scratch my own code to decode the p.b. file.

The lowest level tools that are provided is CodedInputStream. But yes, you will effectively have to "parse" the message yourself. Look at the code that is generated for the mergeFrom method of your message to get an idea for how it works, and you can read the encoding documentation:


You can definitely figure out what is going on, but it will be a bit of a pain. Good luck,

Evan Jones


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