Writing a Minecraft server from scratch in Bash (2022)
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My thoughts on writing a Minecraft server from scratch in Bash - https://news.ycombinator.com/item?id=30347501 - Feb 2022 (90 comments)
And tryauuum, I think the author only needed powers of two to emulate floating point in the first place. So they could just divide said number by 2 a number of times.
https://github.com/taviso/ctypes.sh
Then they can access libm, poll(), select() and so on from bash :)
Amazing, installing now. I want to be part of the problem.
Meaning if it requires bash plus some specially installed compiled c code, then it might as well require c or python or anything else and there is no point in calling it "written in bash", or writing it in mostly-bash-plus-special-plugin.
I do know who I'm speaking to so please assume I say this respectfully. :) I have no problem with a "pointless" project like that as I'll show in a second.
That said, this minecraft project itself relies on externals like xxd when it doesn't need to, so using ctypes.sh would be no worse in this case, so you are right, in this case they might as well have.
But for the record it is possible to read, store, manipulate, do math on, and output binary in pure bash without anything like dd or xxd.
The only byte that is a problem is null, and there is a way to deal with that. You can't directly store a null, but you can detect that you read one and store that info, and reconstruct it on output later, or do math on it, use it's numerical value as an array index or byte offset or whatever the byte is for.
For a minimal example, just copying a binary file: while LANG=C IFS= read -d '' -r -n 1 x ;do printf '%c' "$x" ;done <bin1 >bin2
That's a bit too minimal since it doesn't show what other kinds of things you can do that are more useful than cat-without-cat.
A bit more generic and useful: https://gist.github.com/bkw777/c1413d0e3de6c54524ddae890fe8d...
The LANG=C, IFS= , and -d'' all combine to render all bytes accessible except 0x00, and then the return value from read() tells you the difference between "we read a 0x00" and "we didn't read anything" and "input ended"
And it doesn't have to use < and > on the overall while() comand either. You can exec 3<>file_or_fifo_or_tty and read -u3 / printf >&3 etc inside the loop instead.
An example reading from a serial port: https://gist.github.com/bkw777/ddde771cc85fdd888c7ec74953193...
Used in anger: https://github.com/bkw777/pdd.sh see tpdd_read, tpdd_write, file_to_fhex, str_to_shex reading and writing both a serial port and local files and doing all kinds of processing on the data.
And these loops are not even subshells let alone externals. You can manipulate variables inside the loop and you are still in the same original context. I'd say parent shell but there are no childern.
Those all read a single byte at a time with read -n 1, but they don't have to.
You can read without the -n1 and each iteration of the loop will collect as much as it can between nulls instead of always one byte. That would consume less ram and less loop iterations.
But the things I'm using them for want to slice & dice the individual bytes and byte-ranges at numerical offsets anyway and the data is always small (by todays standards) so the array-of-hex-pairs is just too convenient where a[n] == byte n, and all bytes are treated the same whether printable, non-printable, or null, and aside from merely storing and regenerating the bytes with printf you can also use the numerical values directly as well by simply prepending 0x, so 0x$n or 0x${a[n]} almost anywhere you would normally have a simple integer. So you can do math on them and use them as array indexes and byte offsets etc.
Read the 2nd byte of h[] as a length of the payload to follow, and clip out that payload: ${h[@]:2:0x${h[1]}}
https://github.com/taviso/ctypes.sh/blob/master/test/select.... https://github.com/taviso/ctypes.sh/blob/master/test/poll.sh
Yes, it is crazy :)
a single binary that is less than 2M bytes, universal, way more capable than many people think.
with shellcheck and good habits, bash can be readable and safe as well.
if you want something extra, you can always use C/C++ to add those utilities without using more involved FFI etc, and without pip/npm/etc to load who knows how many dependencies.
My favorite thing to do with shellcheck: add it to CI. Developers hate this one trick!
A lot of times CI and Dockerfiles have inline bash scripts. My next favorite thing to do is to move all of that inlined bash to their own script files. Now that CI has shellcheck: all that stuff gets checked too! Developers seem to hate this though because it's "less readable". Less readable my ass, it's way more safe.
Next problem: the same bash scripts are now in the same files in multiple repositories (a distributed build). I'm open to ideas for improvements here.
Minecraft (Java) is as much of a game engine for others to build on as it is a game itself.
I don’t think Minecraft is number four on the list. It might be number two.
More competitive games can’t afford any type of easy reverse engineering due to the cheating factor.
Click on any mod, and you can see the decompiled source. The mods use function hooking to run before or after certain functions are called rather than the event based system you see in Minecraft plugins.
The nearly-infinite expandability and modularity of Minecraft is partially due to the simplicity of the art, core game mechanics, and lack of storyline. Good mods are harder to make when the world they must integrate into is more complex.
I think this means a lot of games wouldn't see the kind of sustained success Minecraft has seen, even with more "open" development practices.
I hypothesize that the "open world" craze of years past was an attempt to capture Minecraft magic, but those games lacked the thematic open-endedness that really facilitates Minecraft's longevity.
I've heard from someone I know that played both extensively that minetest is less prone to losing everything for data corruption (never happened once in minetest, regularly in minecraft after a while. But sample size is 1).
I've also been on ZFS nearly the whole time. Are you certain Minecraft actually corrupted your data file, or do you suffer underlying hardware failure?