Answer by Lundin for c - memcopy for embedded system
Unfortunately, this function is quite naively written to the point where you would be much better off with a plain byte-by-byte loop:for(size_t i=0; i<size; i++){ src[i] = dst[i];}Benchmark and...
View ArticleAnswer by Lundin for Embedded IoT: local data storage (Second Update)
Overall the code is well-written and easy to read. I found no major things to remark on, just details:cvaluetypes is only used by the .c file and should be declared static, to achieve private...
View ArticleAnswer by Lundin for Multi-threaded application performance in C
First of all, get rid of your secret macro language so that other programmers who don't know your what your secret names mean can read the code. This means replace the mysterious, unreadable...
View ArticleAnswer by Lundin for C function that emulates string concatenation operator...
The main issue with this is that variadic functions have non-existent type safety. It is better to avoid them - it's one of those old things in C that's simply broken.I would suggest to instead write a...
View ArticleAnswer by Lundin for Implementation of the trigonometric functions for real...
One remark is that you should get rid of all the needless branching and code repetition. It's bad for performance and code maintenance both.Given an angle you should be able to:Take it's absolute...
View ArticleAnswer by Lundin for Fixed memory manager in C
You can't really implement a memory manager system like this in standard C. It would have to rely on standard extensions and specific compiler options. The main reason for this is "the strict aliasing...
View ArticleAnswer by Lundin for Unsigned 32-bit integer to binary string function
As already said in other reviews, you should switch to caller allocation. And there's no initialize the string at all, just overwrite all of it.As for the algorithm itself, or in general, go with...
View ArticleAnswer by Lundin for tokenize char array with PolarSSL library
I don't know how this lib works but in general terms, replacing the switch with a look-up table should help with readability/maintenance and performance both. Since there's just 15 items, we don't need...
View ArticleAnswer by Lundin for Ring buffer for Arduino
Review addressing the embedded system aspects, assuming the target is Arduino/AVR 328P:Implementing destructors for a class to be used in a bare metal embedded system is very fishy. If you find...
View ArticleAnswer by Lundin for Software ECC embedded with a parallel NAND Flash interface
From what I remember ST Cortex M4 has some "wannabe cache"-like feature, "ART accelerator", something like that. This is supposedly mainly there to reduce wait states. But if it works like normal...
View ArticleAnswer by Lundin for Circle & Sphere Calculator
It's bad practice to use non-standard functions needlessly. Instead of calling non-standard _stricmp all over the place, you can just iterate over the input string once and call tolower on every...
View ArticleAnswer by Lundin for My first C program: quadratic formula calculator code
Overall clear and readable. Some remarks:atoi is one of those standard library functions that should never be used. It is 100% equivalent to strtol family of functions, except that the latter have...
View ArticleAnswer by Lundin for UPDATED: str_join() function, not present in standard C...
After some long discussion in comments regarding changing the whole concept... here are the main problems:Variadic functions are slow, very type-unsafe and should be avoided in general.Caller...
View ArticleAnswer by Lundin for substr() function, not present in standard C library
Error checks like if ((!str) || (!*str)) and if ((start_index < 0) || (end_index < 0) || (end_index < start_index)) etc don't belong inside a library function. It's the caller's responsibility...
View ArticleAnswer by Lundin for Text-based Tic-Tac-Toe in C
The overall pattern here is that you write code in needlessly complex ways. Good C programming practice is to write code as simple as possible, obeying the KISS principle.Using octal notation with no...
View ArticleAnswer by Lundin for K&R Exercise 3-3: Expand Shorthand Notations (e.g. a-d...
I strongly recommend to avoid K&R since it teaches bad style and is very much outdated. This review will focus on general C programming rather than commenting on your specific algorithm.Invalid...
View ArticleAnswer by Lundin for "Smart" (ish) pointer in C
It isn't possible to implement smart pointers sensibly in C because it lacks "RAII". It would be possible to implement a garbage collector by multi-threading, but one of the benefits of using C in the...
View ArticleComment by Lundin on Generic ring-buffer
Amusingly, I just looked up some proprietary code for a ring buffer implementation I did back in 2009. It has race condition locks so it's more complex than your version #1. But as it turns out, I did...
View ArticleComment by Lundin on Range coder with simple adaptive frequency model
@Leo Usually you'd wait a week or so to let everyone chime in - if you still need feedback on the updated code, the best way is probably to ask a new question. Maybe someone has the time to study &...
View ArticleComment by Lundin on Determining if a C-style string is alphabetic
@RolandIllig I'm of the opinion that input sanitation should be done at the point where the input might go corrupt and not in some completely unrelated library. Such as ensuring that no string contains...
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