make StructLayout serializable

src/data/StructLayout.cpp

@@ -1,5 +1,6 @@
 #include "StructLayout.hpp"
 
+#include <map>
 #include <cstring>
 #include <climits>
 #include <string.h>
@@ -13,6 +14,27 @@ using namespace data;
 static_assert(sizeof(float) == sizeof(int32_t));
 static_assert(sizeof(double) == sizeof(int64_t));
 
+FieldType data::FieldType_from_string(std::string_view name) {
+    std::map<std::string_view, FieldType> map {
+        {"int8", FieldType::I8},
+        {"int16", FieldType::I16},
+        {"int32", FieldType::I32},
+        {"int64", FieldType::I64},
+        {"float32", FieldType::F32},
+        {"float64", FieldType::F64},
+        {"char", FieldType::CHAR},
+    };
+    return map.at(name);
+}
+
+FieldConvertStrategy data::FieldConvertStrategy_from_string(std::string_view name) {
+    std::map<std::string_view, FieldConvertStrategy> map {
+        {"reset", FieldConvertStrategy::RESET},
+        {"clamp", FieldConvertStrategy::CLAMP}
+    };
+    return map.at(name);
+}
+
 StructLayout StructLayout::create(const std::vector<Field>& fields) {
     std::vector<Field> builtFields = fields;
     std::unordered_map<std::string, int> indices;
@@ -325,3 +347,42 @@ std::string_view StructLayout::getChars(
     auto ptr = reinterpret_cast<const char*>(src + field.offset);
     return std::string_view(ptr, strnlen(ptr, field.elements));
 }
+
+std::unique_ptr<dynamic::Map> StructLayout::serialize() const {
+    auto map = std::make_unique<dynamic::Map>();
+    for (const auto& [name, index] : indices) {
+        auto& fieldmap = map->putMap(name);
+        const auto& field = fields[index];
+        fieldmap.put("type", to_string(field.type));
+        if (field.elements != 1) {
+            fieldmap.put("length", field.elements);
+        }
+        if (field.convertStrategy != FieldConvertStrategy::RESET) {
+            fieldmap.put("convert-strategy", to_string(field.convertStrategy));
+        }
+    }
+    return map;
+}
+
+void StructLayout::deserialize(dynamic::Map* src) {
+    std::vector<Field> fields;
+    for (auto& [name, value] : src->values) {
+        if (auto fieldmapptr = std::get_if<dynamic::Map_sptr>(&value)) {
+            const auto& fieldmap = *fieldmapptr;
+
+            auto typeName = fieldmap->get<std::string>("type");
+            FieldType type = FieldType_from_string(typeName);
+            
+            int elements = fieldmap->get("length", 1);
+
+            auto convertStrategy = FieldConvertStrategy::RESET;
+            if (fieldmap->has("convert-strategy")) {
+                convertStrategy = FieldConvertStrategy_from_string(
+                    fieldmap->get<std::string>("convert-strategy")
+                );
+            }
+            fields.push_back(Field {type, name, elements, convertStrategy});
+        }
+    }
+    *this = create(fields);
+}

src/data/StructLayout.hpp

@@ -7,6 +7,7 @@
 #include <optional>
 
 #include "typedefs.hpp"
+#include "interfaces/Serializable.hpp"
 
 namespace data {
     enum class FieldType {
@@ -14,6 +15,14 @@ namespace data {
         COUNT
     };
 
+    inline const char* to_string(FieldType type) {
+        const char* names[] = {
+            "int8", "int16", "int32", "int64", "float32", "float64", "char" 
+        };
+        return names[static_cast<int>(type)];
+    }
+    FieldType FieldType_from_string(std::string_view name);
+
     /// @brief Sorted by severity
     enum class FieldIncapatibilityType {
         NONE = 0,
@@ -28,7 +37,7 @@ namespace data {
     };
 
     inline constexpr int sizeof_type(FieldType type) {
-        const int sizes[static_cast<int>(FieldType::COUNT)] = {
+        const int sizes[] = {
             1, 2, 4, 8, 4, 8, 1
         };
         return sizes[static_cast<int>(type)];
@@ -42,10 +51,18 @@ namespace data {
     /// @brief Strategy will be used if value can't be left the same on conversion
     enum class FieldConvertStrategy {
         /// @brief Reset field value
-        RESET,
+        RESET = 0,
         /// @brief Clamp field value if out of type range
         CLAMP
     };
+    
+    inline const char* to_string(FieldConvertStrategy strategy) {
+        const char* names[] = {
+            "reset", "clamp"
+        };
+        return names[static_cast<int>(strategy)];
+    }
+    FieldConvertStrategy FieldConvertStrategy_from_string(std::string_view name);
 
     struct Field {
         FieldType type;
@@ -58,13 +75,25 @@ namespace data {
         int offset;
         /// @brief Byte size of the field
         int size;
+
+        bool operator==(const Field& o) const {
+            return type == o.type && 
+                   name == o.name && 
+                   elements == o.elements &&
+                   convertStrategy == o.convertStrategy &&
+                   offset == o.offset &&
+                   size == o.size;
+        }
+        bool operator!=(const Field& o) const {
+            return !operator==(o);
+        }
     };
     
-    class StructLayout {
+    class StructLayout : public Serializable {
         int totalSize;
         std::vector<Field> fields;
         std::unordered_map<std::string, int> indices;
-    public:
+    
         StructLayout(
             int totalSize,
             std::vector<Field> fields,
@@ -73,6 +102,16 @@ namespace data {
             fields(std::move(fields)),
             indices(std::move(indices))
         {}
+    public:
+        StructLayout() : StructLayout(0, {}, {}) {}
+
+        bool operator==(const StructLayout& o) const {
+            // if fields are completely equal then structures are equal
+            return fields == o.fields;
+        }
+        bool operator!=(const StructLayout& o) const {
+            return !operator==(o);
+        }
 
         /// @brief Get field by name. Returns nullptr if field not found.
         /// @param name field name
@@ -83,7 +122,6 @@ namespace data {
             if (found == indices.end()) {
                 return nullptr;
             }
-            
             return &fields.at(found->second);
         }
 
@@ -183,5 +221,8 @@ namespace data {
 
         [[nodiscard]]
         static StructLayout create(const std::vector<Field>& fields);
+
+        std::unique_ptr<dynamic::Map> serialize() const override;
+        void deserialize(dynamic::Map* src) override;
     };
 }

src/interfaces/Serializable.hpp

@@ -7,6 +7,6 @@
 class Serializable {
 public:
     virtual ~Serializable() { }
-    virtual std::unique_ptr<dynamic::Map>  serialize() const = 0;
+    virtual std::unique_ptr<dynamic::Map> serialize() const = 0;
     virtual void deserialize(dynamic::Map* src) = 0;
 };

src/util/SmallHeap.hpp

@@ -3,6 +3,7 @@
 #include <cstdint>
 #include <cstring>
 #include <vector>
+#include <limits>
 #include <stdexcept>
 
 namespace util {
@@ -62,9 +63,15 @@ namespace util {
         /// @param size entry size
         /// @return temporary entry pointer 
         /// @attention pointer becomes invalid after allocate(...) or free(...)
-        uint8_t* allocate(Tindex index, Tsize size) {
+        uint8_t* allocate(Tindex index, size_t size) {
+            const auto maxSize = std::numeric_limits<Tsize>::max();
+            if (size > maxSize) {
+                throw std::invalid_argument(
+                    "requested "+std::to_string(size)+" bytes but limit is "+
+                    std::to_string(maxSize));
+            }
             if (size == 0) {
-                throw std::runtime_error("size is 0");
+                throw std::invalid_argument("zero size");
             }
             ptrdiff_t offset = 0;
             if (auto found = find(index)) {

test/data/StructLayout.cpp

@@ -114,3 +114,20 @@ TEST(StructLayout, ConvertWithLoss) {
     EXPECT_EQ(dstLayout.getChars(dst, "text"), "tru");
     EXPECT_EQ(dstLayout.getInteger(dst, "someint"), INT8_MAX);
 }
+
+TEST(StructLayout, Serialization) {
+    std::vector<Field> fields {
+        Field {FieldType::CHAR, "text", 5},
+        Field {FieldType::I16, "someint", 1},
+        Field {FieldType::F64, "pi", 1},
+    };
+    auto layout1 = StructLayout::create(fields);
+    auto serialized = layout1.serialize();
+
+    std::cout << *serialized << std::endl;
+
+    StructLayout layout2;
+    layout2.deserialize(serialized.get());
+
+    EXPECT_EQ(layout1, layout2);
+}