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To go even further, how much is it different from C# or C++? There you'd just declare the appropriate structs and bitcast.

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That works okay only for fixed-sized structs that don't require any transformation of their members-- otherwise you'll need to write a traditional parser.

It is there in Prolog version too. Search for "FileSize" on the page.

What I mean is that if you need to parse a format that has variable-sized structures, you can't just memcpy them into a struct because structs have a fixed size. Additionally sometimes you need to parse a value into a more tractable representation, for example those octal ASCII strings in the tar format, which requires some additional processing that isn't possible with loading/serializing a struct.

Which is also there in the Prolog code.

Sorry, isn't that undefined behaviour?

Not in C# for sure. Not a C++ expert, but I believe reinterpret_cast behavior is defined too.

You can have it as part of unsafe code, hence why the bytecode verifier won't validate Assemblies with unsafe code.

https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...

I believe verifier is fine with unsafe code.

Also not sure what does it have to do with defined/undefined behavior. Even if it is not verifiable, the behavior is still defined.

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