https://github.com/tokazama/swapstreams.jl

Encode endianness in your I/O stream for automatic byte swapping.
https://github.com/tokazama/swapstreams.jl

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Encode endianness in your I/O stream for automatic byte swapping.

• Host: GitHub
• URL: https://github.com/tokazama/swapstreams.jl
• Owner: Tokazama
• License: mit
• Created: 2020-08-12T05:24:24.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2024-08-12T20:00:05.000Z (3 months ago)
• Last Synced: 2024-10-10T11:07:00.441Z (about 1 month ago)
• Language: Julia
• Size: 26.4 KB
• Stars: 2
• Watchers: 2
• Forks: 1
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# SwapStreams.jl

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From the documentation of `read(io::IO, T)` in the Base Julia library...

> Note that Julia does not convert the endianness for you. Use `ntoh` or `ltoh for this purpose.

...but `SwapStreams` does!

`SwapStreams` exports a simple type (`SwapStream`) that wraps any I/O stream.

Once constructed, a `SwapStream` will byte swap any read/write operation if appropriate.

```julia

julia> using SwapStreams

julia> s = SwapStream(IOBuffer());  # assume byte swapping is necessary

julia> write(s, [1:10...]);         # byte swap each element before writing to buffer

julia> seek(s, 0);

julia> read!(s.io, Vector{Int}(undef, 10))  # raw data from buffer

10-element Vector{Int64}:

  72057594037927936

 144115188075855872

 216172782113783808

 288230376151711744

 360287970189639680

 432345564227567616

 504403158265495552

 576460752303423488

 648518346341351424

 720575940379279360

julia> seek(s, 0);

julia> read!(s, Vector{Int}(undef, 10))  # byte swapped data from buffer

10-element Vector{Int64}:

  1

  2

  3

  4

  5

  6

  7

  8

  9

 10

```

One can directly tell a `SwapStream` to byte swap or not by specifying `true` or `false` at the time of its construction.

Alternatively, one may specify whether the stream is big or little endian with the exported constants `BigEndian` and `LittleEndian`.

```julia

julia> using SwapStreams

julia> io = IOBuffer();

julia> SwapStream(true, io) == SwapStream(io)  # does byte swap

true

julia> SwapStream(false, io) ==    # explicitly do not byte swap

       SwapStream(ifelse(ENDIAN_BOM == BigEndian, BigEndian, LittleEndian), io)  # since stream has same endian type as system no swap

true

```

Note that we set the stream's endianness to the same as the system's so that it wouldn't perform byte swapping.