1 files changed, 67 insertions, 0 deletions
diff --git a/bzipper_macros/src/impls/decode_enum.rs b/bzipper_macros/src/impls/decode_enum.rs
new file mode 100644
index 0000000..c773de2
--- /dev/null
+++ b/bzipper_macros/src/impls/decode_enum.rs
@@ -0,0 +1,67 @@
+// Copyright 2024 Gabriel Bjørnager Jensen.
+//
+// This file is part of bZipper.
+//
+// bZipper is free software: you can redistribute
+// it and/or modify it under the terms of the GNU
+// Lesser General Public License as published by
+// the Free Software Foundation, either version 3
+// of the License, or (at your option) any later
+// version.
+//
+// bZipper is distributed in the hope that it will
+// be useful, but WITHOUT ANY WARRANTY; without
+// even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Less-
+// er General Public License along with bZipper. If
+// not, see <https://www.gnu.org/licenses/>.
+
+use crate::DiscriminantIter;
+
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{DataEnum, Fields, Token, Variant};
+use syn::punctuated::Punctuated;
+
+#[must_use]
+pub fn decode_enum(data: &DataEnum) -> TokenStream {
+	let mut match_arms = Punctuated::<TokenStream, Token![,]>::new();
+
+	for (discriminant, variant) in DiscriminantIter::new(&data.variants) {
+		let mut chain_commands = Punctuated::<TokenStream, Token![,]>::new();
+
+		for field in &variant.fields {
+			let command = field.ident
+				.as_ref()
+				.map_or_else(
+					||           quote! { ::bzipper::Decode::decode(stream)? },
+					|field_name| quote! { #field_name: ::bzipper::Decode::decode(stream)? },
+				);
+
+			chain_commands.push(command);
+		}
+
+		let value = match *variant {
+			Variant { ident: ref variant_name, fields: Fields::Named(  ..), .. } => quote! { Self::#variant_name { #chain_commands } },
+			Variant { ident: ref variant_name, fields: Fields::Unnamed(..), .. } => quote! { Self::#variant_name(#chain_commands) },
+			Variant { ident: ref variant_name, fields: Fields::Unit, .. }        => quote! { Self::#variant_name },
+		};
+
+		match_arms.push(quote! { #discriminant => #value });
+	}
+
+	match_arms.push(quote! {
+		value => return ::core::result::Result::Err(::bzipper::error::DecodeError::InvalidDiscriminant(value))
+	});
+
+	quote! {
+		#[inline]
+		fn decode(stream: &mut ::bzipper::IStream) -> ::core::result::Result<Self, ::bzipper::error::DecodeError> {
+			let value = match (<isize as ::bzipper::Decode>::decode(stream)?) { #match_arms };
+			Ok(value)
+		}
+	}
+}