Add binary_to_atom/1 and binary_to_exiting_atom/1

Both functions have been introduced with OTP23 and they default to utf8.

Signed-off-by: Davide Bettio <davide@uninstall.it>

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Support for utf8 encoding to `*_to_atom` and `atom_to_*` functions
+- `binary_to_atom/1` and `atom_to_binary/1` that default to utf8 (they were introduced with OTP23)
 
 ### Fixed
 

libs/estdlib/src/erlang.erl

@@ -53,9 +53,11 @@
     list_to_integer/1,
     list_to_tuple/1,
     iolist_to_binary/1,
+    binary_to_atom/1,
     binary_to_atom/2,
     binary_to_integer/1,
     binary_to_list/1,
+    atom_to_binary/1,
     atom_to_binary/2,
     atom_to_list/1,
     float_to_binary/1,
@@ -582,6 +584,16 @@ list_to_tuple(_List) ->
 iolist_to_binary(_IOList) ->
     erlang:nif_error(undefined).
 
+%%-----------------------------------------------------------------------------
+%% @param   Binary  Binary to convert to atom
+%% @returns an atom from passed binary
+%% @doc     Convert a binary to atom, defaults to utf8.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec binary_to_atom(Binary :: binary()) -> atom().
+binary_to_atom(_Binary) ->
+    erlang:nif_error(undefined).
+
 %%-----------------------------------------------------------------------------
 %% @param   Binary  Binary to convert to atom
 %% @param   Encoding encoding for conversion (any of latin1, utf8 or unicode)
@@ -613,6 +625,17 @@ binary_to_integer(_Binary) ->
 binary_to_list(_Binary) ->
     erlang:nif_error(undefined).
 
+%%-----------------------------------------------------------------------------
+%% @param   Atom        Atom to convert
+%% @returns a binary with the atom's name
+%% @doc     Convert an atom to a binary, defaults to utf8.
+%% Only latin1 encoding is supported.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec atom_to_binary(Atom :: atom()) -> binary().
+atom_to_binary(_Atom) ->
+    erlang:nif_error(undefined).
+
 %%-----------------------------------------------------------------------------
 %% @param   Atom        Atom to convert
 %% @param   Encoding    Encoding for conversion (any of latin1, utf8 or unicode)

src/libAtomVM/nifs.c

@@ -1942,12 +1942,10 @@ static term nif_erlang_binary_to_existing_atom_2(Context *ctx, int argc, term ar
 
 static term binary_to_atom(Context *ctx, int argc, term argv[], int create_new)
 {
-    UNUSED(argc);
-
     term a_binary = argv[0];
     VALIDATE_VALUE(a_binary, term_is_binary);
 
-    term encoding = argv[1];
+    term encoding = (argc == 2) ? argv[1] : UTF8_ATOM;
 
     const char *atom_string = term_binary_data(a_binary);
     size_t atom_string_len = term_binary_size(a_binary);

src/libAtomVM/nifs.gperf

@@ -39,10 +39,12 @@ binary:split/2, &binary_split_nif
 calendar:system_time_to_universal_time/2, &system_time_to_universal_time_nif
 erlang:atom_to_binary/2, &atom_to_binary_nif
 erlang:atom_to_list/1, &atom_to_list_nif
+erlang:binary_to_atom/1, &binary_to_atom_nif
 erlang:binary_to_atom/2, &binary_to_atom_nif
 erlang:binary_to_float/1, &binary_to_float_nif
 erlang:binary_to_integer/1, &binary_to_integer_nif
 erlang:binary_to_list/1, &binary_to_list_nif
+erlang:binary_to_existing_atom/1, &binary_to_existing_atom_nif
 erlang:binary_to_existing_atom/2, &binary_to_existing_atom_nif
 erlang:delete_element/2, &delete_element_nif
 erlang:erase/1, &erase_nif