Main

Converted PCA to be multithreaded and use libpackjpg instead of calling
the old packjpg executable. This works much better! Need to handle a few
error conditions and do some more testing with decompress.

Adding ProtectedAndSynchronizedQueue.

Remaking a few changes that seem to have been missed in the merge (?).

Updated packJPG to latest merged version. Also updated PCA CMake to build packJPG as an external project.

Adding the all important "-march=native" compile flag to the packJPG CMakeLists.txt.

Moved things around so that the main thread breaks off pieces of work and hands them to the threads. This version has less than half the runtime of the previous version for the Photos library test set!

I finally found the mystery error that I've been trying to figure out for a while now. The issue was the dreaded too many file descriptors open. This was caused by not closing the pipe() file descriptors from the parent. I also noticed that handing each instance of packjpg the maximum number of files it can take leads to problems. I guess this is also a cause of "too many file descriptors open", so I have limited the number of files handed to each instance of packjpg to 40. The entire program now runs to completion using my Photos library as a (quite large) test data set!

Fixing the bug I discovered yesterday... I meant to use rfind() instead of find(). I should be ready for another full test.

WIP commit, stashing these debugging changes so I can go mobile.

Finished up the changes to make argv a std::vector instead of a regular array. I also implemented the changes to control the size of argv based on system configuration and potentially spawn packJPG multiple times in order to handle a very large number of files. I ran a test on my Photos library and it sort of worked but I ran into some issues that I still need to diagnose.