fix snappy crc32c checksum

[andyxning]

Motivation:

Explain here the context, and why you're making that change.
What is the problem you're trying to solve.

Modification: The Snappy crc32c checksum produced by SnappyFrameEncoder maybe failed to be validated on other languages snappy decoder, such as golang/snappy.

Describe the modifications you've done.

Result:

Fixes #.

If there is no issue then describe the changes introduced by this PR.

This will make the 4-byte cast later after the mask operation. Because whether retaining the higher 4-7 bytes in a long java type will make difference in (checksum >> 15 | checksum << 17) + 0xa282ead8 result.

[netty-bot]

Can one of the admins verify this patch?

[andyxning]

/cc @trustin @normanmaurer

[normanmaurer]

@andyxning can you add a testcase ?

[andyxning]

@normanmaurer Will do.

[normanmaurer]

@andyxning please ping me once done.

[andyxning]

@normanmaurer Update is done. PTAL.

[andyxning]

@normanmaurer If this PR will be merged, when will the next release will be cut?

[normanmaurer]

@netty-bot test this please

[normanmaurer]

@andyxning can you please fix the checkstyle error ?:

20:51:33 [INFO] Starting audit...
20:51:33 [ERROR] /code/codec/src/main/java/io/netty/handler/codec/compression/Snappy.java:659:20: 'typecast' is not followed by whitespace. [WhitespaceAfter]
20:51:33 [ERROR] /code/codec/src/test/java/io/netty/handler/codec/compression/SnappyTest.java:244: Line is longer than 120 characters (found 129). [LineLength]
20:51:33 Audit done.

[andyxning]

@normanmaurer Comments addressed. PTAL again.

[normanmaurer]

@netty-bot test this please

[normanmaurer]

@andyxning I just noticed you did not sign our ICLA yet... Can you do and let me know once done ?

https://netty.io/s/icla

[normanmaurer]

@andyxning there are test failures... not sure if your change is incorrect or if the tests needs to be fixed ?

[andyxning]

@normanmaurer CLA is Done. codes are updated.

[normanmaurer]

@netty-bot test this please

[normanmaurer]

@andyxning there are still failures

[johnou]

Test Result (4 failures / ±0)

io.netty.handler.codec.compression.SnappyFrameDecoderTest.testInvalidChecksumDoesNotThrowException
io.netty.handler.codec.compression.SnappyFrameEncoderTest.testStreamStartIsOnlyWrittenOnce
io.netty.handler.codec.compression.SnappyFrameEncoderTest.testSmallAmountOfDataIsUncompressed
io.netty.handler.codec.compression.SnappyTest.testCalculateChecksum

[andyxning]

@netty-bot test this please

[andyxning]

@normanmaurer Ut are resolved. PTAL. This is the last time that i will ping you for reviewing this PR, i promise. :-)

[normanmaurer]

@netty-bot test this please

[normanmaurer]

@andyxning thanks a lot!

[andyxning]

@normanmaurer When will the next release will be cut and a new jar will be pushed to maven?

[martinfurmanski]

Is this a breaking change?

[normanmaurer]

@martinfurmanski I dont think so... Why you think it is ? To me it seems like we did not correctly calculate the checksum before.

[martinfurmanski]

@normanmaurer I didn't look at the details, but what I mean is if the prior patch version of netty is talking with this version, are they now calculating differently and can mismatch?

[normanmaurer]

@martinfurmanski I didn't think about this... yes I think this could happen if the crc value overflows Integer.MAX_VALUE.