On 06.08.2021 16:33, Vijay Marupudi wrote: > Hello! > > I was curious if Guile would be willing to provide a series of > new procedures for resizing contiguous memory regions. > > (bytevector-resize! <bytevector> new-size [fill]) > (vector-resize! <vector> new-size [fill]) > > The [fill] parameter could be used if the new-size is bigger than > the current size. > > This would make writing imperative code easier and more > performant. I acknowledge that it is not idiomatic Scheme to use > mutable data structures, however this is useful to me for > dealing with large amounts of text data, in which I need random > access and flexible data storage. It would allow me to move off > my custom C extension vector and allow me to use other > vector-* functions. > > Ideally, this would use libc's `realloc` to make the resize > quick, so that it can avoid data copying whenever possible. > > Regards > > Vijay Marupudi > PhD Student in Human Centered-Computing > Georgia Tech > Sounds like a good idea to me. I didn't know realloc() was a thing in C (I don't write much C) and I suppose it's not possible to implement equivalent functionality with equivalent performance purely in Scheme.
I'm on vacation for the next three weeks and will try to write a patch to implement this if no one beats me to it. :-) One consideration is how this should behave in the case of bytevectors that were created from an FFI pointer. In the FFI, you provide a pointer and specify how long the bytevector should be, which means it's a memory-unsafe operation. I think it would be ideal to offer a way of forcing an in-place resize, basically overriding the formerly provided size value. That means it's also memory-unsafe, but in some cases that's what you want. -- Taylan
