FastIOBuffers aims to provide faster alternatives to Base.IOBuffer, which as of time of writing allocates memory even when e.g. a Float64 is written to or read from it.
FastWriteBuffer solves the allocation problem for the write use case. On 1.1.0, using IOBuffer:
using BenchmarkTools
const N = 1000
@btime write(buf, x) evals = N setup = begin
x = rand(Float64)
buf = IOBuffer(Vector{UInt8}(undef, N * Core.sizeof(x)), read=false, write=true)
endresults in 15.582 ns (1 allocation: 16 bytes), while
using BenchmarkTools
using FastIOBuffers
const N = 1000
@btime write(buf, x) evals = N setup = begin
x = rand(Float64)
buf = FastWriteBuffer(Vector{UInt8}(undef, N * Core.sizeof(x)))
endresults in 10.759 ns (0 allocations: 0 bytes)
Similarly, FastReadBuffer can be used in place of IOBuffer for reading. On 1.1.0, using IOBuffer:
using BenchmarkTools, Random
const N = 1000
@btime read(buf, Float64) evals = N setup = begin
rng = MersenneTwister(1)
writebuf = IOBuffer()
map(1 : N) do _
write(writebuf, rand(rng, Float64))
end
buf = IOBuffer(take!(writebuf))
endresults in 3.368 ns (0 allocations: 0 bytes), while replacing IOBuffer with FastReadBuffer results in 1.344 ns (0 allocations: 0 bytes).