Fix gzip compression/decompression over 4 GiB data size

[yosh-matsuda]

I found gzip compression feature does not work correctly for large data (over 4 GiB).
It seems that compression should repeat with the correct chunk size until the end of data.
I have checked this fixes the issue with the large-data post request.

The same issue can occur with gzip decompression and has been fixed, but I haven't tested it yet.
Could you review this PR?

[yhirose]

@yosh-matsuda, thanks for the pull request. Could you add at least one unit test to test/test.cc to validate your fix before I start reviewing?

[yosh-matsuda]

@yhirose I added the gzip compression and decompression test for large random data. This test fails on the master branch as follows and I checked it will be fixed. Please note that the test requieres about 13GB memory.

Note: Google Test filter = GzipDecompressor.LargeRandomData
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from GzipDecompressor
[ RUN      ] GzipDecompressor.LargeRandomData
test.cc:2913: Failure
Value of: decompressed_data.size()
  Actual: 134217728
Expected: data_size
Which is: 4429185024
[  FAILED  ] GzipDecompressor.LargeRandomData (28526 ms)
[----------] 1 test from GzipDecompressor (28526 ms total)

[yhirose]

@yosh-matsuda, thanks for adding the unit test. I have reviewed the code and looks very good! I personally feel that the zlib usage example page should use this code instead. :)

The only problem is that the unit tests run on 'ubuntu-latest'in GitHub Actions is always killed (and probably on macOS as well)... I am not sure of the exact reason, but it seems like it's due to timeout. (On my iMac with 3.8 GHz Quad-Core Intel i5 and 24GB Memory, this test takes about 3 minutes. So the total time of tests is about 5 minutes.)

Fortunately, the unit tests run on Windows works with no problem. So I surround the test with #ifdef _WIN32 ... #endif at ccbddd8, so that we at least run this test on Windows.

Anyway, thanks for the excellent contribution!