Building a Classic Mac OS App in Rust

Wesley Moore:

The first challenge was finding a decent specification for the three versions of MacBinary. I was eventually I was able to dig up the following:

• MacBinary I
• MacBinary II
• MacBinary III

I then set about building the parser. I reused the binary parser code from Allsorts since I was already familiar with that code. I hit another roadblock when it came to the CRC in the header. Nothing describes the actual CRC algorithm used. I tried the CRC reversing tool CRC RevEng without success. A lot of existing code seemed to use an implementation that originated in a late 80’s UNIX utility, mcvert, that has unclear licensing. I wanted to use the Rust crc crate instead.

[…]

Due to its heritage most of the Mac OS toolbox functions use the Pascal calling convention, which LLVM does not support. To bridge the C (and Rust) world to this Pascal world I had to create trampoline functions in C for each toolbox function that I wanted to call from Rust[…]

[…]

I used the “Downloading a URL With HTTP” example from the Networking With Open Transport book as a guide for the functions I needed.

Previously:

• Rescuing Files From Classic Mac OS...with Swift

Emulator Mac Mac OS 8 Parser Pascal Resource Fork Rust Programming Language WebAssembly

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