Pure Elixir encoder/decoder for BCS format.
Encoder/Decoder for:
- Booleans
- Signed 8-bit, 16-bit, 32-bit, 64-bit, and 128-bit integers
- Unsigned 8-bit, 16-bit, 32-bit, 64-bit, and 128-bit integers
- Option
- Unit (an empty value)
- Fixed and variable length sequences
- UTF-8 Encoded Strings
- Tuples
- Structures (aka “structs”)
- Externally tagged enumerations (aka “enums”)
- Maps
If available in Hex, the package can be installed
by adding bcs to your list of dependencies in mix.exs:
def deps do
[
{:bcs, "~> 0.1.0"}
]
end# Define the struct
defmodule MyStruct do
@derive {Bcs.Struct,
label: :string,
chars: [:u8 | 4], # <<= we use improper list for fixed length array
boolean: :bool,
maps: %{:u8 => :string},
}
defstruct [:label, :chars, :boolean, :maps, :field]
end
my_struct = %MyStruct{
label: "hello",
chars: 'abcd',
boolean: true,
maps: %{1 => "1", 2 => "2"},
field: "this field will be ignored"
}
# encode
my_struct
|> Bcs.encode!()
# then decode
|> Bcs.decode!(MyStruct)| Rust Type | Syntax |
|---|---|
u8, s8, u16, u256, ... |
:u8, :s8, :u16, :u256, ... |
bool |
:bool |
() |
nil |
Option<T> |
[t | nil] |
[T] |
[t] |
[T; N] |
[t | n] |
String |
:string |
(T1, T2) |
{t1, t2} |
MyStruct |
MyStruct |
enum E |
E |
Map<K, V> |
%{k => v} |
Also we have a special type for treating [u8] as binary instead of charlist
[u8] | [:byte]
[u8; N] | [:byte \| n]
defmodule Foo do
use Bcs.TaggedEnum, [
{:variant0, :u16},
{:variant1, :u8},
{:variant2, :string},
:variant3
]
endSome valid values for type Foo: {:variant0, 42}, {:variant2, "hello"}, :variant3, etc.