Hacker News Reader

Comment by ulbu | Hacker News Reader

you need different packed structs for little- and big-endian data. and casting with little-endian data is a nightmare - you need to reverse-cascade your struct fields to be in accordance with the little-endian bit-pattern. (or have a comptime function that does it for you, of course. but then you lose all declarations for the struct). what should be a simple writing down of a protocol is now a pedantic and error-prone ordeal.

View on HN

This has been largely solved by everyone agreeing to use little endian. There aren't really use cases for wanting to convert between them.

Does that mean there are no file formats thatbuse big endian? And network byte order isn't a thing?

    > there are no file formats thatbuse big endian

if someone chooses to do that they own the problems.

    > network byte order isn't a thing

if the network serializes/deserializes for you (kernel primitives) then you don't care what it does. if it doesn't and for some reason you choose to use big endian, again, you own the problem.

If someone chooses to load a TIFF or a PSD or an AIFF or…

then you either use an existing C library (the most likely approach) or if you are determined to re-implement it you have to be careful parsing their bytes.

Network byte order has nothing to do with the kernel and you have to care about it

It’s a standard because neither side of the connection knows the endianness of the other side so there must be a standard. That standard is big endian regardless of your architecture or kernel or anything else

So any serialization intended go over the network should be big endian

right, so a zig app will just do little endian. in the very unlikely event you have it running on a big endian machine you have to do extra work.

You may have never done socket programming, or do you use wrapper libs in Zig? Because you have to send the kernel big endian port numbers for example.

What do you do if you program a kernel in Zig, or just generally do low level networking?

My point is to refute the statement that everyone has agreed to little endian, and so there aren't use cases to want to do conversion. Programs do not exist in a vacuum, most programs do not.

Well you would, of course, have a mapping layer between wire types and domain types, like in any good codebase. You do the endianness conversion at that boundary, and then you can just send it out.

> You do the endianness conversion

Exactly my point.

And what happens if your zig app happens to be a network driver running on a microcontroller?

Generally those edge cases are always the same endianness. You don't need big and little endianness versions of the structures. What's important is that everyone agrees on the same thing.

There are some cursed data formats where something is little endian in some places, big endian in other places

Generally speaking though the types you handle in business logic (what your application actually do) shouldn't have any endianness

Or you just go ahead and forget that big endian ever existed. It's not coming back.

it’s little-endian protocols that require that you juggle your struct fields.

plus, there are still big-endian protocols that will stay for a long time. for example, MIDI clip files in MIDI 2.0 are big-endian.

Reply on news.ycombinator.com