SwapStreams.jl

Encode endianness in your I/O stream for automatic byte swapping.
Author Tokazama
Popularity
0 Stars
Updated Last
1 Year Ago
Started In
August 2020

SwapStreams.jl

Build Status stable-docs dev-docs codecov

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> 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 Array{Int64,1}:
  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 Array{Int64,1}:
  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> 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.

Required Packages

Used By Packages

No packages found.