Add RSASSA-PSS support

[ackerleytng]

Would appreciate any feedback on this work in progress! I'll be adding more test cases

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[ackerleytng]

@googlebot I signed it!

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[qiwzhang]

Thanks you for your contribution.

[ackerleytng]

I'm a little confused about variable naming on the google style guide, do let me know if there's anything I should change!

[ackerleytng]

I'd like to propose using the direct initializer syntax (without new). Specifically for this implementation, the handle to implemented_args never leaves the isImplemented function, so C++ is able to insert the destructor appropriately (just before the program exits).

I wrote a small program to illustrate this here and here's the output:

$ g++ ok.cc && valgrind --leak-check=full --show-leak-kinds=all ./a.out
==354120== Memcheck, a memory error detector
==354120== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==354120== Using Valgrind-3.16.0.GIT and LibVEX; rerun with -h for copyright info
==354120== Command: ./a.out
==354120==
Foobar()
11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
Foobar()
11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111~Foobar()
==354120==
==354120== HEAP SUMMARY:
==354120==     in use at exit: 32 bytes in 1 blocks
==354120==   total heap usage: 3 allocs, 2 frees, 73,760 bytes allocated
==354120==
==354120== 32 bytes in 1 blocks are still reachable in loss record 1 of 1
==354120==    at 0x4839DEF: operator new(unsigned long) (vg_replace_malloc.c:342)
==354120==    by 0x1092A1: leak(char) (in /home/ackerleytng/scratch/a.out)
==354120==    by 0x109424: main (in /home/ackerleytng/scratch/a.out)
==354120==
==354120== LEAK SUMMARY:
==354120==    definitely lost: 0 bytes in 0 blocks
==354120==    indirectly lost: 0 bytes in 0 blocks
==354120==      possibly lost: 0 bytes in 0 blocks
==354120==    still reachable: 32 bytes in 1 blocks
==354120==         suppressed: 0 bytes in 0 blocks
==354120==
==354120== For lists of detected and suppressed errors, rerun with: -s
==354120== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

The output shows that when leak() is called, the destructor ~Foobar() is never called, and valgrind reports a leak due to the call to new, whereas the destructor does its work correctly in noLeak(), not in every iteration of the loop, but at the end of the program.

[qiwzhang]

OK, thanks.

[ackerleytng]

Thanks! I suppose we can close #49 ?