# `Mojoler.Dsl.Bytes`
[🔗](https://github.com/thanos/mojoler/blob/v0.1.0/lib/mojoler/dsl/bytes.ex#L1)

Binary examples generated from `tools/dsl/decls.json`.

`shift/1` copies the payload and adds 1 to each byte, wrapping at 255.
`borrow_len/1` reads the size of the caller's binary and does not copy it.
The byte function lives in `native/examples/bytes_user.mojo`.

# `borrow_len`

```elixir
@spec borrow_len(binary()) :: {:ok, non_neg_integer()} | {:error, :not_binary}
```

Returns the byte size of `bin` without copying the payload.

## Returns

  * `{:ok, size}`
  * `{:error, :not_binary}` for a list or a bitstring that is not a binary

## Examples

    iex> Mojoler.Dsl.Bytes.borrow_len(<<1, 2, 3, 4>>)
    {:ok, 4}

    iex> Mojoler.Dsl.Bytes.borrow_len(<<1::7>>)
    {:error, :not_binary}

# `load_nif`

```elixir
@spec load_nif() :: :ok | {:error, term()}
```

Loads `priv/native/libdsl_bytes.so`.

A second call returns `{:error, {:reload, charlist}}`.

## Examples

    iex> Mojoler.Dsl.Bytes.load_nif()
    {:error, {:reload, ~c"NIF library already loaded (reload disallowed since OTP 20)."}}

# `shift`

```elixir
@spec shift(binary()) :: {:ok, binary(), non_neg_integer()} | {:error, :not_binary}
```

Returns a copy of `bin` with each byte increased by 1, modulo 256.

`bin` must be a binary. A bitstring that is not a binary is an error.

## Returns

  * `{:ok, shifted, nbytes}` where `nbytes` is the byte size
  * `{:error, :not_binary}`

## Examples

    iex> Mojoler.Dsl.Bytes.shift(<<1, 2, 255>>)
    {:ok, <<2, 3, 0>>, 3}

    iex> Mojoler.Dsl.Bytes.shift(<<>>)
    {:ok, <<>>, 0}

    iex> Mojoler.Dsl.Bytes.shift([1, 2])
    {:error, :not_binary}

---

*Consult [api-reference.md](api-reference.md) for complete listing*