mmapped file slightly faster

src/main/julia/main.jl

@@ -36,14 +36,20 @@ end
 function main()
     open("../../../measurements.txt", "r") do f
         println("Start")
+        sz = Base.stat(f).size
+        data = mmap(f, Vector{UInt8}, sz)
+        idxs = findall(isequal(0x0a), data)
         stations = Dict{String,StationMeasurements}()
         iteration = 0
-        for line in eachline(f)
+        last_idx = 1
+        for i in eachindex(idxs)
             if iteration % 1000000 == 0 && iteration > 0
                 print("\x1b[J\x1b[H")
                 percent = round((iteration / 1000000000) * 100; digits=2)
                 println("$(percent)%")
             end
+            line = String(data[last_idx:idxs[i]-1])
+            last_idx = idxs[i] + 1
             station, temp_str = rsplit(line, ";")
             temp = parse(Float32, temp_str)
             if haskey(stations, station)