Level 33 C++ sourcerer. https://about.me/marek.knapek
Yes, I know this. It took me long time to figure this out. My entire life I focused on technical skills / programming / math / logic. As I deemed them most important for the job. I was like: “Hey, if you cannot program, why do you work as programmer (you stupido)?” Only few years ago I realized that even as programmer (as opposed to sales man) you really need those “meh” soft skills. And that they are really important and I should not call them “meh”. I’m very good at solving problems, improving product’s performance, memory consumption, discovering and fixings bugs, security vulnerabilities. But I’m very very bad at communicating my skills and communicating with people in general. I’m not able to politely tell people that theirs idea is bad, I just say “that’s stupid”. And I’m mostly/sometimes right (if I’m not 100% sure, I don’t say anything), but the damage caused by the way I say it is often inreversible. That post of mine about the job interview and CV was half joke and half reality. I just freeze/stutter when I’m asked something that is obvious because it is written I my CV. I’m immediately thinking “Did he not received the CV?” or “Did he not read it?” “Why the fuck is he not prepared for the call? Why are we wasting time asking me what should be obvious because I sent it in advance?” I’m more robot than human. Put me in front of problem and forget to tell me that it is impossible to solve … and I will solve it. But easy small talk … disaster. Communicating what the problem really was … disaster. Communicating how I solved it … disaster. “It was not working before and now it works fine, what the hell do you want from me now?” Yes, I’m very bad in team, in collective. I didn’t know the reason why, but since few years ago I know the root of the problem. It’s not that everybody around me is stupid and don’t know basic stuff (what I consider basic), but me unable to communicate with other humans.
The interview starts … the interviewer asks me “Tell me about yourself.” … I respond “Did you receive my CV? I put all important details about me … right there. What questions do you have about my past jobs?” The interviewer encourages me again to tell him about myself, my past projects, etc. … Me: Awkward silence. … Me to myself: Dafuq? Should I read the CV from top to bottom OR WHAT?
Yes, but (there is always a but) it does not apply if you implement off-line encryption. Meaning no on-line service encrypting / decrypting attacker provided data (such as SSL / TLS / HTTPS). Meaning if you are running the cipher on your own computer with your own keys / plaintexts / ciphertexts. There is nobody to snoop time differences or power usage differences when using different key / different ciphertext. Then I would suggest this is fine. The only one who can attack you is yourself. In fact, I implemented AES from scratch in C89 language, this source code is at the same time compatible with C++14 constexpr evaluation mode. I also implemented the Serpent cipher, Serpent was an AES candidate back then when there were no AES and Rijndael was not AES yet. The code is on my GitHub page.
std::vector::reserve + std::vector::push_back in loop is sub-optimal, because push_back needs to check for re-allocation, but that never comes.
std::vector::resize + std::vector::operator[] in loop is also sub-optimal, because resize default-initializes all elements only to be overwritten soon anyway.
This article’s author suggests push_back_unchecked.
I suggest std::vector::insert with pair of random access iterators with custom dereference operator that does the “transform element” or “generate element” functionality. The standard will have resize_and_overwrite hopefully soon.
Moar discussion:
https://codingnest.com/the-little-things-the-missing-performance-in-std-vector/
https://twitter.com/horenmar_ctu/status/1695823724673466532
https://twitter.com/horenmar_ctu/status/1695331079165489161
https://www.reddit.com/r/cpp/comments/162tohr/the_little_things_the_missing_performance_in/
https://www.reddit.com/r/cpp/comments/162tohr/the_little_things_the_missing_performance_in/jy21hgd/
https://twitter.com/basit_ayantunde/status/1644895468399337473
https://twitter.com/MarekKnapek/status/1645272474517422081
https://www.reddit.com/r/cpp/comments/cno9ep/improving_stdvector/
Another alternative to C++ exceptions (instead of return code) is to use global (or thread local) variable. This is exactly what errno that C and POSIX are using or GetLastError what Windows is using. Of course, this has its own pros and cons.
Makes sense, how would you represent floor(1e42
) or ceil(1e120)
as integer? It would not fit into 32bit (unsigned) or 31bit (signed) integer. Not even into 64bit integer.
This is true in real world also, not only in computer world or programming world. Think of steam engine, it enabled sooo much progress in other fields. Also invention of lathe and precision measuring and engineering. Before that, invention of “simple machines” such as pulley, bolt/screw, windlass, lever. The same in math, physics, chemistry and so on.
Oversimplified:
More questions:
The same style of question would be: How to create a hammer if in order to create a hammer you need a hammer? How was the first hammer created? Answer: By more primitive hammer, or something that is no hammer, but almost works as a hammer.
For more info read about bootstrapping compilers. Or trusting the trust by Ken Thompson.
You have stack buffer out of bounds write. On line
52
you declareh
an array of70
unsigned int
s. On line57
you store reference to such array. Later, on line35
you write out of bounds, one element past end of the array. The_SPR_history[i]
writes to_SPR_history[70]
. Created an issue: https://github.com/X64X2/sh/issues/1