add compress function && update clean function

[yyt030]

No description provided.

[golangcibot]

should check returned error before deferring df.Close()

[codecov]

Codecov Report

Merging #3 into master will decrease coverage by 36.93%.
The diff coverage is 25%.

@@             Coverage Diff             @@
##           master       #3       +/-   ##
===========================================
- Coverage   85.71%   48.78%   -36.94%     
===========================================
  Files           1        1               
  Lines          42       82       +40     
===========================================
+ Hits           36       40        +4     
- Misses          4       37       +33     
- Partials        2        5        +3

Impacted Files	Coverage Δ
glc.go	48.78% <25%> (-36.94%)	⬇️

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