samplig rate conversion

Started by twain March 18, 2006
robert bristow-johnson wrote:
> > one thing i would have to say, Erik, while i respect the technical merit of > your code (i've only looked at libsndfile), it is awfully opaque to read.
Funny thing is, I have had a number of people dive into the libsndfile code and add significant chunks of functionality, and then sending me a patch. The first I hear of it is a the patch arrives in my my inbox. Many of those people have also said that the libsndfile code base was rather easy to work on.
> a > few years ago, i tried extracting the salient functions out of it to include > in a simple C program i was writing to do some (undefined) music/sound > processing on some .wav files. whenever i did, it left so many undefined > symbols and such that i ended up writing a simple .wav file reader from > scratch.
Like any large piece of code, libsndfile has had a bunch of common functionality abstracted away into internal helper functions and then called from throughout the rest the code. This is commonly considered good software engineering practice. This and the concientious use of test driven development has made the libsndfile code base extremely robust and reliable. libsndfile is extremely widely used. It is installed on a large proportion of Linux systems and is used for file I/O on Mac Win32 and Linux) in CSound5, SuperCollider3, Chuck and a number of other widely used pieces of sound software. Even with this wide usage, bug reports are extremely rare and are fixed with a very short turn-around. Part of the reason for the relatively bug free nature of libsndfile is the use of internal helper functions. This also makes it difficult to pull a single file out of libsndfile and hope to compile it into something else. I don't apologize for that.
> i'm just an EE who is a code minimalist
As am I. If I wasn't a minimalist libsndfile would be written in C++ with deeply nested class heirarchies and templates and the standard template library throughout. As if it is, libsndfile uses little code outside the ISO C99 standard.
> your code looks > like something written by a hard-core professional
I'l take that as a compliment :-). I do make my living writing code in projects of 100k plus lines.
> working in a big company like Micro$oft.
But that is not. If it wasn't you rbj, I'd take that as an insult :-).
> that may be good, in some regards, but it is not transparent.
May its a culture thing. For experienced software engineers working in C on Linux, libsndfile does not look all that strange, especially if they have had some experience in writing device drivers on Linux. For someone coming from outside that culture, the libsndfile may look rather opaque. Erik -- +-----------------------------------------------------------+ Erik de Castro Lopo +-----------------------------------------------------------+ "There are two kinds of large software systems: those that evolved from small systems and those that don't work." -- Seen on, then quoted by amk
Randy Yates wrote:
> > If Einstein were a software developer, I'm sure his philosophy would be > > "Write code as simple as possible, but no simpler."
And I'd agree with that as long as "simple as possible" includes proper testing of corner cases, error returns from functions, proper validation of untrusted input etc. I seen statistics somewhere that for any significnt piece of code, up to 50 percent of the code (by line count) was input validation and error handling Erik -- +-----------------------------------------------------------+ Erik de Castro Lopo +-----------------------------------------------------------+ "C++ : You won't live long enough to learn it all from experience." -- Peter Miller (author of Aegis)