https://github.com/azurefx/cunion.jl

C-like unions for Julia.
https://github.com/azurefx/cunion.jl

julia union

Last synced: about 1 month ago
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C-like unions for Julia.

• Host: GitHub
• URL: https://github.com/azurefx/cunion.jl
• Owner: azurefx
• License: mit
• Created: 2019-12-05T10:11:24.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2019-12-11T03:18:52.000Z (almost 5 years ago)
• Last Synced: 2024-10-11T14:41:22.856Z (about 1 month ago)
• Topics: julia, union
• Language: Julia
• Homepage:
• Size: 7.81 KB
• Stars: 5
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# CUnion.jl

[![Build Status](https://travis-ci.org/azurefx/CUnion.jl.svg?branch=master)](https://travis-ci.org/azurefx/CUnion.jl)

This package provides C-style primitive union types for Julia.

## Usage

Add the macro `@union` to a `struct` definition to make a C union:

```julia

@union struct U

  x::UInt8

  y::UInt16

end

```

Then `U` can be instantiated with one of its field types:

```julia

julia> u = U(Int8(-1))

U1(0x00ff)

julia> u1.y

0x00ff

julia> reinterpret(Int16, u)

255

```

Nested anonymous structs are also supported. For example, the `LARGE_INTEGER` type from Win32

```cpp

typedef union _LARGE_INTEGER {

  struct {

    DWORD LowPart;

    LONG HighPart;

  } DUMMYSTRUCTNAME;

  struct {

    DWORD LowPart;

    LONG HighPart;

  } u;

  LONGLONG QuadPart;

} LARGE_INTEGER;

```

Can be written as

```julia

@union struct LargeInteger

  struct u

    low::UInt32

    high::UInt32

  end

  quad::UInt64

end

```

```julia

julia> li=LargeInteger(0x00112233aabbccdd)

LargeInteger(0x00112233aabbccdd)

julia> li.u.high

0x00112233

```

## TODO

1. Improved reinterpret_cast performance?

2. Convenient methods to update fields?

3. Sub-typing and generic support?