mirror of
https://github.com/go-gitea/gitea
synced 2024-12-24 22:04:43 +01:00
d77176912b
* Migrate to go modules * make vendor * Update mvdan.cc/xurls * make vendor * Update code.gitea.io/git * make fmt-check * Update github.com/go-sql-driver/mysql * make vendor
20 lines
No EOL
2.2 KiB
Markdown
20 lines
No EOL
2.2 KiB
Markdown
go-unsnap-stream
|
|
================
|
|
|
|
This is a small golang library for decoding and encoding the snappy *streaming* format, specified here: https://github.com/google/snappy/blob/master/framing_format.txt
|
|
|
|
Note that the *streaming or framing format* for snappy is different from snappy itself. Think of it as a train of boxcars: the streaming format breaks your data in chunks, applies snappy to each chunk alone, then puts a thin wrapper around the chunk, and sends it along in turn. You can begin decoding before receiving everything. And memory requirements for decoding are sane.
|
|
|
|
Strangely, though the streaming format was first proposed in Go[1][2], it was never upated, and I could not locate any other library for Go that would handle the streaming/framed snappy format. Hence this implementation of the spec. There is a command line tool[3] that has a C implementation, but this is the only Go implementation that I am aware of. The reference for the framing/streaming spec seems to be the python implementation[4].
|
|
|
|
For binary compatibility with the python implementation, one could use the C-snappy compressor/decompressor code directly; using github.com/dgryski/go-csnappy. In fact we did this for a while to verify byte-for-byte compatiblity, as the native Go implementation produces slightly different binary compression (still conformant with the standard of course), which made test-diffs harder, and some have complained about it being slower than the C.
|
|
|
|
However, while the c-snappy was useful for checking compatibility, it introduced dependencies on external C libraries (both the c-snappy library and the C standard library). Our go binary executable that used the go-unsnap-stream library was no longer standalone, and deployment was painful if not impossible if the target had a different C standard library. So we've gone back to using the snappy-go implementation (entirely in Go) for ease of deployment. See the comments at the top of unsnap.go if you wish to use c-snappy instead.
|
|
|
|
[1] https://groups.google.com/forum/#!msg/snappy-compression/qvLNe2cSH9s/R19oBC-p7g4J
|
|
|
|
[2] https://codereview.appspot.com/5167058
|
|
|
|
[3] https://github.com/kubo/snzip
|
|
|
|
[4] https://pypi.python.org/pypi/python-snappy |