helium / erlang-xorf

Erlang binding to the xorf crate

erlang-xorf

This library is a NIF wrapper for the xorf family of xor filters.

Both binary fuses and xor filters are suported in 8 16, and 32 bits per entry.

NOTE: The initialization list to a filter must be a unique list of 64 bit integers. Use a good hashing function over your data and make sure to dedupe it before passing it into the xorf:new/2 functions. Lists with duplicates may cause undefined behavior.

Table of Contents

• Table of Contents
• Installation
• Example Usage
• Serialization

Installation

Install from hex.pm.

For rebar3:

%% rebar.config

{deps, [
  {xorf, "1.0.0"}
]}.

For Mix:

## mix.exs

defp deps do
  [
    {:xorf, "~> 1.0.0"}
  ]
end

Example Usage

NOTE The list of integers given to xorf:new/2 must be deduped to avoid undefined behavior.

For an xor filter:

{ok, Filter} = xorf:new({exor, 8}, [1, 2, 3]),
true   = xorf:contains(Filter, 1),
false  = xorf:contains(Filter, 5),

Note that the number of bits per entry implies the likelihood of false positives in the resulting filter.

For a binary fuse:

{ok, Filter} = xorf:new({binary_fuse, 8}, [1, 2, 3]),
true   = xorf:contains(Filter, 1),
false  = xorf:contains(Filter, 5),

Serialization

Binary serialization and deserialization is achieved using the bincode.

For example, given a binary for an 8 bit binary fuse:

{ok, Bin} = xorf:to_bin(Filter),
{ok, DFilter} = xorf:from_bin({binary_fuse, 8}, Bin),
true   = xorf:contains(DFilter, 1),
false  = xorf:contains(DFilter, 5),