From 70a3abcb3aad4c5e74b4b9fa6ac76508ac157f55 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Fri, 5 Jan 2024 05:58:49 +0100
Subject: codec: Adding a basic csv decoder. Unfinished

---
 modules/codec/c++/csv.h            | 47 +++++++++++++++++++++++++++++++++++++
 modules/codec/c++/schema.h         | 48 +++++++++++++++++++++++++++++++-------
 modules/codec/c++/schema_factory.h |  3 +++
 3 files changed, 90 insertions(+), 8 deletions(-)

(limited to 'modules/codec/c++')

diff --git a/modules/codec/c++/csv.h b/modules/codec/c++/csv.h
index 67c2c1d..3727829 100644
--- a/modules/codec/c++/csv.h
+++ b/modules/codec/c++/csv.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <forstio/error.h>
+
 #include "data.h"
 
 namespace saw {
@@ -7,8 +9,53 @@ namespace encode {
 struct Csv {};
 }
 
+namespace impl {
+template<typename Schema, typename FromDecode>
+struct csv_encode {
+	static_assert(always_false<T>, "Case not supported");
+};
+
+template<typename  T, size_t Dim>
+struct csv_encode<schema::Array<T,Dim>, FromDecode> {
+	static_assert(Dim == 1, "Only one dimension is allowed.");
+	static_assert(!is_array<T>::value, "Array of an array is not allowed.");
+	static_assert(is_tuple<T>::value || is_struct<T>::value, "Only struct or tuples allowed inside a csv array");
+
+	using Schema = schema::Array<T,Dim>;
+
+	static error_or<void> encode(const data<Schema, FromDecode>& from, data<Schema, encode::Csv>& to){
+		if constexpr (is_struct<T>::value){
+			auto eov = csv_encode<T>::encode_header(to);
+			if(eov.is_error()){
+				return eov;
+			}
+		}
+
+		for(std::size_t i = 0; i < from.size(); ++i){
+			auto eov = csv_encode<T>::encode(from.at(i), to);
+			if(eov.is_error()){
+				return eov;
+			}
+		}
+		
+		return void_t{};
+	}
+};
+
+template<>
+struct csv_encode<schema::String, FromDecode> {
+	using Schema = schema::String;
+
+	static error_or<void> encode(const data<Schema, FromDecode>& from, data<Schema, encode::Csv>& to){
+
+		return void_t{};
+	}
+};
+}
+
 template<typename Schema>
 class codec<Schema, encode::Csv> {
+	static_assert(is_array<Schema>::value, "Only an Array is allowed as a base value");
 public:
 	template<typename FromEncode>
 	static error_or<void> encode(const data<Schema, FromEncode>& from, data<Schema,encode::Csv>& to){
diff --git a/modules/codec/c++/schema.h b/modules/codec/c++/schema.h
index 69233fa..576f378 100644
--- a/modules/codec/c++/schema.h
+++ b/modules/codec/c++/schema.h
@@ -28,14 +28,6 @@ struct Union<Member<V, K>...> {};
 
 template <typename T, size_t Dim = 1> struct Array {};
 
-template <class T> struct is_array {
-	constexpr static bool value = false;
-};
-
-template <class T, size_t Dim> struct is_array<schema::Array<T,Dim>> {
-	constexpr static bool value = true;
-};
-
 template<typename T, size_t... S> struct FixedArray {};
 
 template <typename... T> struct Tuple {};
@@ -55,6 +47,7 @@ class Wrapper {};
 
 struct String {};
 
+
 struct SignedInteger {};
 struct UnsignedInteger {};
 struct FloatingPoint {};
@@ -106,4 +99,43 @@ struct Interface<Member<Function<Requests, Responses>,Names>...> {};
 
 // NOLINTEND
 } // namespace schema
+template <class T> struct is_struct {
+	constexpr static bool value = false;
+};
+
+template <class... V, string_literal... K> struct is_struct<schema::Struct<schema::Member<V,K>...>> {
+	constexpr static bool value = true;
+};
+
+template <class T> struct is_string {
+	constexpr static bool value = false;
+};
+
+template <> struct is_string<schema::String> {
+	constexpr static bool value = true;
+};
+
+template <class T> struct is_tuple {
+	constexpr static bool value = false;
+};
+
+template <class... T> struct is_tuple<schema::Tuple<T...>> {
+	constexpr static bool value = true;
+};
+
+template <class T> struct is_array {
+	constexpr static bool value = false;
+};
+
+template <class T, size_t Dim> struct is_array<schema::Array<T,Dim>> {
+	constexpr static bool value = true;
+};
+
+template <class T> struct is_primitive {
+	constexpr static bool value = false;
+};
+
+template <typename T, size_t N> struct is_primitive<schema::Primitive<T,N>> {
+	constexpr static bool value = true;
+};
 } // namespace saw
diff --git a/modules/codec/c++/schema_factory.h b/modules/codec/c++/schema_factory.h
index 91094fe..47185be 100644
--- a/modules/codec/c++/schema_factory.h
+++ b/modules/codec/c++/schema_factory.h
@@ -39,6 +39,9 @@ struct schema_factory<schema::Tuple<T...>> {
 		}
 };
 
+/**
+ * This creates the base schema
+ */
 template<typename T>
 constexpr schema_factory<T> build_schema() noexcept {
 		return {};
-- 
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