From 0302bb7d3b1ab2ac936911a4466a2530650c7b83 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Thu, 9 Nov 2023 21:56:18 +0100
Subject: codec-netcdf: Basic struct and primitive write in working order

---
 c++/codec-netcdf/netcdf.tmpl.h | 156 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 139 insertions(+), 17 deletions(-)

(limited to 'c++/codec-netcdf/netcdf.tmpl.h')

diff --git a/c++/codec-netcdf/netcdf.tmpl.h b/c++/codec-netcdf/netcdf.tmpl.h
index f3b36b8..00bfbf4 100644
--- a/c++/codec-netcdf/netcdf.tmpl.h
+++ b/c++/codec-netcdf/netcdf.tmpl.h
@@ -48,6 +48,125 @@ struct netcdf_is_group<schema::Struct<schema::Member<T,Lits>...>> {
 };
 
 template<typename Schema, typename ToEncode>
+struct netcdf_encode;
+
+template<typename T, size_t N, typename ToEncode>
+struct netcdf_encode<schema::Primitive<T,N>, ToEncode> {
+	using Schema = schema::Primitive<T,N>;
+
+	static error_or<void> encode(const data<Schema, ToEncode>& from, int ncid, int ncvarid){
+		int rc{};
+
+		typename native_data_type<Schema>::type val = from.get();
+
+		rc = nc_put_var(ncid, ncvarid, &val);
+		if(rc != NC_NOERR) {
+			return make_error<err::critical>();
+		}
+
+		return void_t{};
+	}
+	
+	static error_or<void> encode_meta(const data<Schema, ToEncode>& from, int ncid, int ncvarid){
+		(void) from;
+		(void) ncid;
+		(void) ncvarid;
+		return void_t{};
+	}
+};
+
+template<typename... T, string_literal... Lits, typename ToEncode>
+struct netcdf_encode<schema::Struct<schema::Member<T,Lits>...>, ToEncode> {
+	using Schema = schema::Struct<schema::Member<T,Lits>...>;
+
+	template<std::size_t i>
+	static error_or<void> encode_member(const data<Schema, ToEncode>& from, int ncid){
+			using Type = typename parameter_pack_type<i,T...>::type;
+			constexpr string_literal Literal = parameter_key_pack_type<i, Lits...>::literal;
+			{
+				/**
+				 * We have to ask for the internal id of the netcdf structure
+				 */
+				if constexpr (netcdf_is_group<Type>::value){
+					return make_error<err::not_implemented>();
+				}else{
+					int nc_varid{};
+					int rc {};
+					rc = nc_inq_varid(ncid, Literal.data.data(), &nc_varid);
+					if(rc != NC_NOERR) {
+							return make_error<err::critical>();
+					}
+					auto eov = netcdf_encode<Type, ToEncode>::encode(from.template get<Literal>(), ncid, nc_varid);
+					if(eov.is_error()){
+						return eov;
+					}
+				}
+
+			}
+			if constexpr ((i+1) < sizeof...(T)){
+				auto eov = encode_member<i+1>(from, ncid);
+				if(eov.is_error()){
+						return eov;
+				}
+			}
+
+		return void_t{};
+	}
+	
+	static error_or<void> encode(const data<Schema, ToEncode>& from, int ncid){
+		if constexpr (sizeof...(T) > 0){
+				auto eov = encode_member<0>(from, ncid);
+				return eov;
+		}
+		
+		return void_t{};
+	}
+
+	template<std::size_t i>
+	static error_or<void> encode_meta_member(const data<Schema, ToEncode>& from, int ncid){
+			using Type = typename parameter_pack_type<i,T...>::type;
+			constexpr string_literal Literal = parameter_key_pack_type<i, Lits...>::literal;
+			{
+				/**
+				 * We have to ask for the internal id of the netcdf structure
+				 */
+				if constexpr (netcdf_is_group<Type>::value){
+					return make_error<err::not_implemented>();
+				}else{
+					int nc_varid{};
+					int rc {};
+					rc = nc_def_var(ncid, Literal.data.data(), netcdf_primitive_id<Type>::value, 0, nullptr, &nc_varid);
+					if(rc != NC_NOERR) {
+							return make_error<err::critical>();
+					}
+					auto eov = netcdf_encode<Type, ToEncode>::encode_meta(from.template get<Literal>(), ncid, nc_varid);
+					if(eov.is_error()){
+						return eov;
+					}
+				}
+
+			}
+			if constexpr ((i+1) < sizeof...(T)){
+				auto eov = encode_meta_member<i+1>(from, ncid);
+				if(eov.is_error()){
+						return eov;
+				}
+			}
+
+		return void_t{};
+	}
+
+	static error_or<void> encode_meta(const data<Schema, ToEncode>& from, int ncid){
+		if constexpr (sizeof...(T) > 0){
+				auto eov = encode_meta_member<0>(from, ncid);
+				return eov;
+		}
+		
+		return void_t{};
+	}
+};
+
+template<typename Schema, typename ToDecode>
 struct netcdf_decode;
 
 template<typename T, size_t N, typename ToDecode>
@@ -160,24 +279,27 @@ struct netcdf_decode<schema::Struct<schema::Member<T,Lits>...>, ToDecode> {
 				 * We have to ask for the internal id of the netcdf structure
 				 */
 				if constexpr (netcdf_is_group<Type>::value){
-						int nc_group_id{};
-						int rc {};
-						rc = nc_inq_ncid(from, Literal.data.data(), &nc_group_id);
-						if(rc != NC_NOERR) {
-								return make_error<err::critical>();
-						}
-						auto eov = netcdf_decode<Type, ToDecode>::decode(to.template get<Literal>(), nc_group_id);
-						if(eov.is_error()){
-								return eov;
-						}
+					int nc_group_id{};
+					int rc {};
+					rc = nc_inq_ncid(from, Literal.data.data(), &nc_group_id);
+					if(rc != NC_NOERR) {
+							return make_error<err::critical>();
+					}
+					auto eov = netcdf_decode<Type, ToDecode>::decode(to.template get<Literal>(), nc_group_id);
+					if(eov.is_error()){
+							return eov;
+					}
 				}else{
-						int nc_varid{};
-						int rc {};
-						rc = nc_inq_varid(from, Literal.data.data(), &nc_varid);
-						if(rc != NC_NOERR) {
-								return make_error<err::critical>();
-						}
-						auto eov = netcdf_decode<Type, ToDecode>::decode(to.template get<Literal>(), from, nc_varid); 
+					int nc_varid{};
+					int rc {};
+					rc = nc_inq_varid(from, Literal.data.data(), &nc_varid);
+					if(rc != NC_NOERR) {
+							return make_error<err::critical>();
+					}
+					auto eov = netcdf_decode<Type, ToDecode>::decode(to.template get<Literal>(), from, nc_varid); 
+					if(eov.is_error()){
+						return eov;
+					}
 				}
 
 			}
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