Support for ASIO backend on windows

Current state

This is a very early stage attempt. There's lots to do before merging. I just want to start getting some feedback.

Feedback: I'm fairly new to Rust so there's definitely going to be mistakes / non-idiomatic code in here. Feel free to point out anything you think is weird / wrong or ask for explanations.

Things that are working: - The enumerate example - The beep example - Building the ASIO library and linking to it - Creating the bindings to the library with bindgen

Things that still need to be done (non-exhaustive): - [x] The record_wav example - [ ] Supporting all the possible ASIO formats - [x] Allow the CPAL user to set if the want ASIO or WASAPI at with an initialize call - [x] Check for potential threading issue (I'm new to this) - [ ] Stop any panics that could cross FFI boundaries - [x] Add comments and example usage docs - [x] Make the interleaving faster and avoid copying

Usage

1. You need to download the ASIO SDK and unzip it somewhere.
2. Put the full path into the environment variable CPAL_ASIO_DIR eg. with powershell ($env:CPAL_ASIO_DIR="C:\Users\you\my_libs\ASIOSDK2.3")
3. Now you should be able to run "cargo run --example enumerate" Note: The beep example is currently hard set to select ASIO 4 All because there's no way to get the default asio driver and this made testing easier.

Resources

• This is a good write up about how portaudio built there asio backend.
• Theres a pdf in the ASIO sdk called ASIO SDK 2.3.pdf that explains the how ASIO works
• Theres an example of how to write an ASIO host in c++ in ASIOSDK2.3/host/sample/hostsample.cpp

Note: I had to change branches and make this pr because of conflict problems.

该提问来源于开源项目：RustAudio/cpal