Carbon
Folly
Carbon | Folly | |
---|---|---|
18 | 90 | |
16,444 | 27,118 | |
- | 0.6% | |
9.3 | 9.8 | |
3 days ago | 4 days ago | |
PHP | C++ | |
MIT License | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Carbon
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PHP: check dates
Carbon is probably one of the most popular vendors to handle dates in PHP.
- Ask HN: What are some of the most elegant codebases in your favorite language?
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Why was the Carbon library called that?
Official page, at the very bottom.
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Calendar page displaying empty boxes and not days and numbers - $this->date
Let me start by referring you to PHP's DateTime implementation. There is a library called Carbon that uses this DateTime implementation and added almost all the methods you have (but better). So there really is no need to create your own just to be able to display Dutch names. That way to can get rid of the nasty "globals".
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The Wonderful Carbon - Laravel
At first we go to https://carbon.nesbot.com/ Here we will see a lot of interesting information and go deeper into it See also https://github.com/briannesbitt/Carbon
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Need help formatting week day and time
first of all, i think you should use Carbon library. it's available here: https://github.com/briannesbitt/carbon
- Any help will be greatly appreciated
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Do you use a DateTime wrapper?
See: https://github.com/briannesbitt/Carbon/issues/1693
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Creating a Neat DateTime Helper Function in PHP
Working with datetime in PHP could be a real pain if you don't take advantage of popular libraries like Carbon. It's all good until you have to convert dates provided on user input into another timezone (eg. UTC) and vice versa. Other example could be that you have to manage various input datetime formats, and sanitize them into a consistent one before saving it to database.
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Carbon - Float Difference in Months Filtered
Be careful of floatDiffInMonths() which can gives you a lower result (number of months in A < number of months in B) for an interval having more days (number of days in A > number of days in B) due to the variable number of days in months (especially February). By default, we rely on the result of DateTime::diff which is sensitive to overflow. See issue #2264 for alternative calculations.
Folly
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Ask HN: How bad is the xz hack?
https://github.com/facebook/folly/commit/b1391e1c57be71c1e2a...
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Backdoor in upstream xz/liblzma leading to SSH server compromise
https://github.com/facebook/folly/pull/2153
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A lock-free ring-buffer with contiguous reservations (2019)
To set a HP on Linux, Folly just does a relaxed load of the src pointer, release store of the HP, compiler-only barrier, and acquire load. (This prevents the compiler from reordering the 2nd load before the store, right? But to my understanding does not prevent a hypothetical CPU reordering of the 2nd load before the store, which seems potentially problematic!)
Then on the GC/reclaim side of things, after protected object pointers are stored, it does a more expensive barrier[0] before acquire-loading the HPs.
I'll admit, I am not confident I understand why this works. I mean, even on x86, loads can be reordered before earlier program-order stores. So it seems like the 2nd check on the protection side could be ineffective. (The non-Linux portable version just uses an atomic_thread_fence SeqCst on both sides, which seems more obviously correct.) And if they don't need the 2nd load on Linux, I'm unclear on why they do it.
[0]: https://github.com/facebook/folly/blob/main/folly/synchroniz...
(This uses either mprotect to force a TLB flush in process-relevant CPUs, or the newer Linux membarrier syscall if available.)
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Appending to an std:string character-by-character: how does the capacity grow?
folly provides functions to resize std::string & std::vector without initialization [0].
[0] https://github.com/facebook/folly/blob/3c8829785e3ce86cb821c...
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Can anyone explain feedback of a HFT firm regarding implementation of SPSC lock-free ring-buffer queue?
My implementation was quite similar to Boost's spsc_queue and Facebook's folly/ProducerConsumerQueue.h.
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A Compressed Indexable Bitset
> How is that relevant?
Roaring bitmaps and similar data structures get their speed from decoding together consecutive groups of elements, so if you do sequential decoding or decode a large fraction of the list you get excellent performance.
EF instead excels at random skipping, so if you visit a small fraction of the list you generally get better performance. This is why it works so well for inverted indexes, as generally the queries are very selective (otherwise why do you need an index?) and if you have good intersection algorithms you can skip a large fraction of documents.
I didn't follow the rest of your comment, select is what EF is good at, every other data structure needs a lot more scanning once you land on the right chunk. With BMI2 you can also use the PDEP instruction to accelerate the final select on a 64-bit block: https://github.com/facebook/folly/blob/main/folly/experiment...
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Defer for Shell
C++ with folly's SCOPE_EXIT {} construct:
https://github.com/facebook/folly/blob/main/folly/ScopeGuard...
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Is there any facebook/folly community for discussion and Q&A?
Seems like github issues taking a long time to get any response: https://github.com/facebook/folly
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How a Single Line of Code Made a 24-Core Server Slower Than a Laptop
Can't speak for abseil and tbb, but in folly there are a few solutions for the common problem of sharing state between a writer that updates it very infrequently and concurrent readers that read it very frequently (typical use case is configs).
The most performant solutions are RCU (https://github.com/facebook/folly/blob/main/folly/synchroniz...) and hazard pointers (https://github.com/facebook/folly/blob/main/folly/synchroniz...), but they're not quite as easy to use as a shared_ptr [1].
Then there is simil-shared_ptr implemented with thread-local counters (https://github.com/facebook/folly/blob/main/folly/experiment...).
If you absolutely need a std::shared_ptr (which can be the case if you're working with pre-existing interfaces) there is CoreCachedSharedPtr (https://github.com/facebook/folly/blob/main/folly/concurrenc...), which uses an aliasing trick to transparently maintain per-core reference counts, and scales linearly, but it works only when acquiring the shared_ptr, any subsequent copies of that would still cause contention if passed around in threads.
[1] Google has a proposal to make a smart pointer based on RCU/hazptr, but I'm not a fan of it because generally RCU/hazptr guards need to be released in the same thread that acquired them, and hiding them in a freely movable object looks like a recipe for disaster to me, especially if paired with coroutines https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p05...
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Ask HN: What are some of the most elegant codebases in your favorite language?
Not sure if it's still the case but about 6 years ago Facebook's folly C++ library was something I'd point to for my junior engineers to get a sense of "good" C++ https://github.com/facebook/folly
What are some alternatives?
Moment.php - Parse, validate, manipulate, and display dates in PHP w/ i18n support. Inspired by moment.js
abseil-cpp - Abseil Common Libraries (C++)
Chronos - A standalone DateTime library originally based off of Carbon
Boost - Super-project for modularized Boost
Yasumi - The easy PHP Library for calculating holidays
Seastar - High performance server-side application framework
CalendR - The missing PHP 5.3+ calendar management library.
parallel-hashmap - A family of header-only, very fast and memory-friendly hashmap and btree containers.
ExpressiveDate - A fluent extension to PHPs DateTime class.
EASTL - Obsolete repo, please go to: https://github.com/electronicarts/EASTL
Duration for PHP - Working with durations made easy
OpenFrameworks - openFrameworks is a community-developed cross platform toolkit for creative coding in C++.