README.md

BitPacking.jl

BitPacking.jl provides small bit-packed building blocks for Julia array code:

• NArray, NVector, and NMatrix pack a static group of narrow values into one storage value.
• NarrowArray, NarrowVector, and NarrowMatrix view an array of packed groups as a logical array of values.
• NarrowTuple and @NarrowTuple pack heterogeneous isbits values, with optional padding fields.

Packages can extend BitPacking.bitwidth(::Type) for their own narrow scalar types.

Examples

using BitPacking

v = NVector(true, false, true, false, true, false, true, false)

Tuple(v)                 # (true, false, true, false, true, false, true, false)
reinterpret(UInt8, v)    # 0x55

x = Bool[1, 0, 1, 0, 1, 0, 1, 0]
packed = NarrowArray{Bool}(x)

copy(packed) == x        # true
parent(packed)           # Vector{NVector{Bool,8}}

t = @NarrowTuple(0x12, true)

Tuple(t)                 # (0x12, true)
BitPacking.bitwidth(t)   # 9

Installation

using Pkg
Pkg.add("BitPacking")