Can somebody help with this case? ## I've started with reinterpreting some complex types from a binary stream: bytevec = UInt8[0x01, 0x02, 0x00, 0x03, 0x00, 0x00, 0x00] reinterpret(Tuple{Int8, Int16, Int32}, bytevec) # but seems like because of structure alignment I cannot just read # any combina…

For the generated function, you’d have to do it like this: @generated function read_schema_gen2(io::IOBuffer, types::Type...) reads = (:(read(io, $(t.parameters[1]))) for t in types) return :(tuple($(reads...))) end types is a tuple of Type a the time the generation happens, so you have to…

Why isn’t io = IOBuffer(bytevec) result = (read(io, Int8), read(io, Int16), read(io, Int32)) sufficient? I feel I’m missing something from you problem description, but it sounds like a very familiar use case to parse tuples dependent on runtime data. Macros are source code transformations, so i do…

[image] laborg: Why isn’t io = IOBuffer(bytevec) result = (read(io, Int8), read(io, Int16), read(io, Int32)) sufficient? Maybe I didn’t describe the problem well, but there are variable combinations of types. Assume user sending requests for some specific data fields, each time a new combin…

[image] sairus7: It is type-stable and fast for repeated calls? Is that loop over static tuple unwrapped into several reads at compilation? Looks like this code has some overhead comparing to explicit call: function readschema(io::IOBuffer, types::Type...) tuple((read(io,x) for x in type…

what about function readschema2(io::IOBuffer, types) map(type -> read(io,type), types) end For me, it times as 3.105 ns (using @btime)

It is much faster than the first solution, but still much slower than static schema - testing for large arrays: readschema_static(io::IOBuffer) = (read(io, Int8), read(io, Int16), read(io, Int32)) function readvec_static(data::Vector{UInt8}, types::Type...) elsize = mapreduce(sizeof, +, types) …

I think you are just measuring compile time. By the second run, they are equal.

They are not equal on repeated runs. Ok, I will run it with BenchmarkTools: using BenchmarkTools @btime readvec_static($bytevec, types...) # 77.000 μs (2993 allocations: 70.64 KiB) @btime readvec($bytevec, types...) # 3.949 ms (18973 allocations: 632.83 KiB) @btime readvec2($bytevec, types…

Macro for binary data deserialization into tuples of variable types

General Usage

sairus7 April 24, 2020, 10:34am 10

Alternative solution is here: Difference between Type{T} and T when passing type variable inside generated function? - #4 by Elrod

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Macro for binary data deserialization into tuples of variable types

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