Bitcoin full node and query server

June 2022

Archive of the libbitcoin Slack #general channel.

Thursday, June 9, 2022

pmienk19:35

Topic: Dev Weekly Status Time: Jun 9, 2022 01:00 PM Pacific Time (US and Canada) Join Zoom Meeting https://us05web.zoom.us/j/85232961954?pwd=ME5jenh0YWlqUFJlcXptMndxYml4QT09 Meeting ID: 852 3296 1954 Passcode: Et0zKR

evoskuil19:38

Might be a little late.

pmienk19:38

no problem

Thursday, June 16, 2022

pmienk19:30

Topic: Dev Weekly Status Time: Jun 16, 2022 01:00 PM Pacific Time (US and Canada) Join Zoom Meeting https://us05web.zoom.us/j/85232961954?pwd=ME5jenh0YWlqUFJlcXptMndxYml4QT09 Meeting ID: 852 3296 1954 Passcode: Et0zKR

evoskuil23:45

C++23 gives me a function I was just about to write :>>

https://en.cppreference.com/w/cpp/numeric/byteswap

pmienk23:46

23 isn't in the m4 yet

evoskuil23:46

No worries, it's a 4 line impl that requires c++20.

Friday, June 17, 2022

evoskuil00:08

C++ 20 has std::bit_cast<Integer>(const uint8*), so trivial to do no-convert endian functions safely based on casting the contigous bytes directly into the integral. byteswap isn't as great, because it bit casts to a temporary byte vector and then swaps the bytes and recasts. I was trying to avoid the allocation. This is just something that facilitates stream read/write little endianness conversions without intermediate buffering, since the bytes are read out of order.

(edited)

evoskuil00:25

But I suspect there is plenty of optimization available un the C++23 stdlib implementations, so I'll just take this simple impl and replace it later.

evoskuil06:36

Fixed iteration (at compile time) loop flattening using for consexptr(...) :)). Endian conversions no longer need an iterator.

(edited)

I was going to use type constraints for each integral size type, but that's a lot of extra code because the full set of operations needs to repeated in each, and the function declarations. Compiles to the same though.

I also found the Windows intrinsics for byte swapping, and code to do it in x86/x64 assembler, just like the hashing but much much simpler.

And I was easily able to define constexpr values to determine the endianness of the platform. These can be used in template type constraints of if constexpr(...)`

constexpr auto is_native_big_endian =
to_bool(std::bit_cast<std::array<uint8_t, sizeof(size_t)>>(one).back());

constexpr auto is_native_little_endian =
to_bool(std::bit_cast<std::array<uint8_t, sizeof(size_t)>>(one).front());

Simple constexpr bool that works on any platform. Love the "new" language features.

(edited)

jungly13:36

Hey @evoskuil - pulled the latest master from your repo, and noticed those build errors on github actions too. Are you working towards moving up from C++11?

evoskuil16:15

We've moved to c++ 20, just catching CI up to it.

You should check out the interpreter. Variant stack :).

3 replies · jungly, evoskuil · last Jun 30, 2022

jungly04:16

This is so sweet! I wrote a stack and interpreted in lisp recently (why not? :)). Being dynamically typed and all, it was kind of a fun project. This variant thing is cool. I hadn't read about it before this. Thanks for pointing it out.

evoskuil07:26

C++ now has std::variant, built on a c++ union. Visitor pattern that invokes strongly typed handlers.

(edited)

evoskuil07:27

It's soooo cool how it worked out. You should give it a look. /machine

jungly17:30

Saw that commit. Soooo excited you moved to 20!

Am using coroutines for the braidpool stuff. So much nicer than chain of handlers!

evoskuil22:16

I'll take a look at it for network. I want to stick to the strand threading model, but if I can use coroutines to simplify the handing at no additional cost that would be nice.

Thursday, June 23, 2022

evoskuil19:32

Can we do 1:30 today?

pmienk19:34

Sure

pmienk20:01

Topic: Dev Weekly Status Time: Jun 23, 2022 01:30 PM Pacific Time (US and Canada) Join Zoom Meeting https://us05web.zoom.us/j/85232961954?pwd=ME5jenh0YWlqUFJlcXptMndxYml4QT09 Meeting ID: 852 3296 1954 Passcode: Et0zKR

(edited)

Thursday, June 30, 2022

pmienk19:30

Topic: Dev Weekly Status Time: Jun 30, 2022 01:00 PM Pacific Time (US and Canada) Join Zoom Meeting https://us05web.zoom.us/j/85232961954?pwd=ME5jenh0YWlqUFJlcXptMndxYml4QT09 Meeting ID: 852 3296 1954 Passcode: Et0zKR