ndpi_strnstr optimization

[0xA50C1A1]

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• I have signed the ntop Contributor License Agreement at https://github.com/ntop/legal/blob/main/individual-contributor-licence-agreement.md
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• I have updated the documentation (in doc/) to reflect the changes made (if applicable)

Describe changes:

On average, the new implementation is 2.5 times faster. Although, of course, there are test cases where it shows slightly worse results.

Also I wrote a small benchmark to compare different implementations if you're interested.

[IvanNardi]

Could you

• add the benchmark code in tests/performance/, updating the makefile, please?
• add some unit tests (expecially, some corner cases) in example/ndpiReader.c, like you did for strlcpy?

[0xA50C1A1]

Could you

* add the benchmark code in `tests/performance/`, updating the makefile, please?

original one or try to rewrite it in C?

[IvanNardi]

original one or try to rewrite it in C?

Original one!

[0xA50C1A1]

original one or try to rewrite it in C?

Original one!

Ok, sure.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[IvanNardi]

Thanks!