this post was submitted on 15 Nov 2023
1007 points (95.6% liked)

Programmer Humor

19522 readers
131 users here now

Welcome to Programmer Humor!

This is a place where you can post jokes, memes, humor, etc. related to programming!

For sharing awful code theres also Programming Horror.

Rules

founded 1 year ago
MODERATORS
Feyter@programming.dev
anzo@programming.dev
BurningTurtle@programming.dev
pylapp@programming.dev
1007
GoOn (programming.dev)
submitted 1 year ago by mac@programming.dev to c/programmer_humor@programming.dev
108 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] dannym@lemmy.escapebigtech.info 3 points 1 year ago* (last edited 1 year ago) (3 children)

Definitely, tho if you store it as a u32 that is fixed magically. Because 1.2.3.4 and 1.02.003.04 both map to the same number.

What I mean by storing it as a u32 is to convert it to a number, similar to how the IP gets sent over the wire, so for v4:

octet[3] | octet[2] << 8 | octet[1] << 16 | octet[0] << 24

or in more human terms:

(fourth octet) + (third octet * 256) + (second octet * 256^2) + (first octet * 256^3)
[–] p1mrx@sh.itjust.works 2 points 1 year ago (1 children)

Because 1.2.3.4 and 1.02.003.04 both map to the same number.

But 10.20.30.40 and 010.020.030.040 map to different numbers. It's often best to reject IPv4 addresses with leading zeroes to avoid the decimal vs. octal ambiguity.

[–] dannym@lemmy.escapebigtech.info 2 points 11 months ago (1 children)

I don't know why anyone would write their IPs in octal, but fair point

[–] p1mrx@sh.itjust.works 2 points 11 months ago

It's not about how people write them, it's how parsers parse them. IPv4 has been around since 1982, and most parsers interpret leading zeros as octal.

[–] Emma_Gold_Man@lemmy.dbzer0.com 2 points 1 year ago

True enough for database or dictionary storage, but a lot of times things get implemented in arrays where you still wind up with two copies of the same uint32.