Julia IDX Parser

idx.jl

import Base.ntoh
@vectorize_1arg Number Base.ntoh

function readIdx(file_name)
    fs = open(file_name, "r")
    magic_number = read(fs, UInt8, 4)

    if magic_number[3] == 0x08
        idx_type = UInt8
    elseif magic_number[2] == 0x09
        idx_type = Int8
    elseif magic_number[2] == 0x0B
        idx_type = Int16
    elseif magic_number[2] == 0x0C
        idx_type = Int32
    elseif magic_number[2] == 0x0D
        idx_type = Float32
    elseif magic_number[2] == 0x0E
        idx_type = Float64
    end

    dims = Array{Int64}(ntoh(read(fs, Int32, magic_number[4])))

    contents = read(fs, idx_type, prod(dims))

    if idx_type != UInt8 && idx_type != Int8
        contents = ntoh(contents)
    end
    
    out = reshape(contents, tuple(dims...))
    return out 
end