Rich_Morin
The Magick Persistent Cache (MPC) is a memory-mapped file of pixels, used to store image data. ImageMagick maps this into memory, then accesses desired sets of pixels by indexing into the array. Each array element contains a single-precision (32 bit) float for each channel (eg, R, G, B, A).
I’d like to do something similar in Elixir. I assume that I could use a NIF to handle the memory mapping and binary pattern matching to access the pixels, but I’m clueless about the details. Might anyone have a clue (or better, code) to do this sort of thing?
-r
Where Next?
Trending in Questions
Other Trending Topics
Latest on Elixir Forum
Sponsor Spotlight
Build Elixir applications with speed and confidence.
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #library
- #deployment
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #elixirconf
- #channels
- #exunit
- #discussion
- #code-sync
- #podcasts
- #javascript
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixirconf-us
- #ai
- #blog-post
- #elixir-ls
- #phoenix_html
- #iex
- #graphql
- #genstage
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #hex
- #security
- #metaprogramming
Our Sponsors
Build Elixir applications with speed and confidence.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Error tracking, logs, uptime, and Just Enough APM. Built for developers.
Elixir, Erlang & BEAM conferences from Code Sync - join us in 2026!
Practical resources that improve the lives of professional developers.
Producing high quality Elixir screencasts since 2017.
The deployment platform built for Elixir: PaaS ease, VPS control.
The team behind Membrane, Popcorn, LiveDebugger. Available for hire.
Courses that'll move you from confusion to "Aha, now I get it!"
Showing Posts 1 to 1- Show Best Posts
- Show All (oldest first)
- Show All (newest first)
CptnKirk
There’s a chance you get this with OTP 21. They’re moving the file and network io over to NIFs. Try and see if OTP 21’s File.open supports what you’re looking for. Although, I suspect they’re shooting for feature parity, and not added functionality for this release.
In OTP 20 you’d find the data you care about, (or whole file) read that into iodata, then File.open the iodata as ram. That should give a FD for additional File based calls. However, I think you’re still operating in memory at this point without transparent disk syncing. When you’re done with your memory FD copy, you’d write the iodata back out to disk yourself.
Or…you can write your own NIF based io subsystem. Nifsy (GitHub - ericentin/nifsy: A nifty NIF for the FS, providing faster filesystem operations for Elixir · GitHub) exists. Doesn’t directly support mmap’d files, but does show how a NIF based IO library can be written.