Force should pass thru bytes unchanged

[GoogleCodeExporter]

What steps will reproduce the problem?
1. lz4 -cdf on a non-lz4 file, or lz4cat -f on non-lz4 file 

What is the expected output? What do you see instead?

If -f is supplied to 'gzip', 'bzip2' or 'xz' type compressors along with the -c 
and -d options then if the compressor cannot recognise the magic number of the 
file, it passes the bytes through unchanged rather than generating an error. 

This is so the compressors can be strung together in a pipeline. It would be 
useful if lz4 could follow that convention. 

What version of the product are you using? On what operating system?

Please provide any additional information below.

Original issue reported on code.google.com by n...@aldur.co.uk on 3 Feb 2015 at 11:57

[GoogleCodeExporter]

This is interesting. I wasn't aware of such scenario and behavior. I'll look 
into it.

Original comment by yann.col...@gmail.com on 3 Feb 2015 at 4:13

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[GoogleCodeExporter]

Original comment by yann.col...@gmail.com on 3 Feb 2015 at 4:14

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Original comment by yann.col...@gmail.com on 10 Feb 2015 at 9:44

• Changed state: Accepted
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[GoogleCodeExporter]

Preliminary support for "pass-through" mode
available within latest "dev" branch on github :
https://github.com/Cyan4973/lz4/tree/dev

Original comment by yann.col...@gmail.com on 16 Mar 2015 at 7:40

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