refactor: add size argument to array type

Closes: #43

furvm/include/furvm/thing.hpp

@@ -94,16 +94,18 @@ public:
      * @return A clone of this thing.
      */
     thing clone() const {
-        thing res(resolve_type(m_type, m_modules), m_modules, m_allocator);
-        switch (m_type->t) {
+        auto  type = resolve_type(m_type, m_modules);
+        thing res(type, m_modules, m_allocator);
+        switch (type->t) {
         case type_t::Primitive:
         case type_t::Reference: {
             std::memcpy(res.m_data, m_data, m_size);
         } break;
-        case type_t::List: {
-            copy_list(resolve_type(*m_type->list, m_modules), res.get<list_t>(), get<list_t>());
+        case type_t::Array: {
+            copy_list(type, res.get<array_t>(), get<array_t>());
         } break;
-        case type_t::Import: throw std::runtime_error("unreachable");
+        case type_t::Import:
+        default: throw std::runtime_error("unreachable");
         }
         return std::move(res);
     }
@@ -278,23 +280,24 @@ public:
     }
 
     void resize(long_t newSize) {
-        if (m_type->t != type_t::List) throw bad_thing_access();
-        auto& list = get<list_t>();
+        if (m_type->t != type_t::Array) throw bad_thing_access();
+        if (m_type->array.size > 0) throw std::runtime_error("cannot resize a static array");
+
+        auto& list = get<array_t>();
         if (newSize < 0 || newSize == list.size) return;
-        std::byte* newData = new std::byte[compute_size_na(resolve_type(*m_type->list, m_modules)) * newSize];
-        std::memcpy(newData,
-            list.data,
-            compute_size_na(resolve_type(*m_type->list, m_modules)) * std::min(list.size, newSize));
+        std::size_t innerSize = compute_size_na(*m_type->array.type);
+        std::byte*  newData   = new std::byte[innerSize * newSize];
+        std::memcpy(newData, list.data, innerSize * std::min(list.size, newSize));
         list.size = newSize;
         delete[] list.data;
         list.data = newData;
     }
 
     thing at(long_t index) const {
-        if (m_type->t != type_t::List) throw bad_thing_access();
-        auto& list = get<list_t>();
+        if (m_type->t != type_t::Array) throw bad_thing_access();
+        auto& list = get<array_t>();
         if (index < 0 || index >= list.size) throw std::out_of_range("index out of range");
-        thing res              = { *m_type->list, m_modules, m_allocator };
+        thing res              = { std::make_shared<type>(m_type->array.type), m_modules, m_allocator };
         res.get<reference_t>() = list.data; // TODO: Account for padding, alignment and stuff
         return std::move(res);
     }
@@ -306,24 +309,39 @@ public:
         return rsv;
     }
 private:
-    static void copy_list(const type_p& innerType, list_t& dst, const list_t& src) {
-        dst.size = src.size;
-        if (dst.size <= 0) {
-            dst.data = nullptr;
-            return;
-        }
-        if (innerType == nullptr) throw std::runtime_error("inner type should not be null!");
+    static void copy_list(const type_p& arrayType, array_t& dst, const array_t& src) {
+        if (arrayType == nullptr || arrayType->t != type_t::Array || *arrayType->array.type == nullptr)
+            throw std::runtime_error("invalid type");
+
+        auto        innerType   = *arrayType->array.type;
+        std::size_t elementSize = compute_size_na(innerType);
+
+        std::byte*       data    = nullptr;
+        const std::byte* srcData = nullptr;
+        std::size_t      size    = 0;
+        if (arrayType->array.size == 0) {
+            size = dst.dynamic.size = src.dynamic.size;
+            if (dst.dynamic.size < 0) {
+                dst.dynamic.data = nullptr;
+                return;
+            }
+
+            srcData = src.dynamic.data;
+            data = dst.dynamic.data = new std::byte[dst.dynamic.size];
+        } else {
+            data    = dst.data;
+            srcData = src.data;
+            size    = arrayType->array.size;
+        }
 
-        std::size_t size = compute_size_na(innerType) * dst.size;
-        dst.data         = new std::byte[size];
         switch (innerType->t) {
         case type_t::Primitive:
         case type_t::Reference: std::memcpy(dst.data, src.data, size); break;
-        case type_t::List:
+        case type_t::Array:
             for (std::size_t i = 0; i < size; ++i) {
-                copy_list(*innerType->list,
-                    *std::launder(reinterpret_cast<list_t*>(dst.data)),
-                    *std::launder(reinterpret_cast<list_t*>(src.data)));
+                copy_list(*innerType->array.type,
+                    *std::launder(reinterpret_cast<array_t*>(data + (i * elementSize))),
+                    *std::launder(reinterpret_cast<const array_t*>(srcData + (i * elementSize))));
             }
             break;
         case type_t::Import: throw std::runtime_error("unresolved type");
@@ -334,7 +352,10 @@ private:
         switch (type->t) {
         case type_t::Primitive: return type->primitive;
         case type_t::Reference: return sizeof(reference_t);
-        case type_t::List: return sizeof(list_t);
+        case type_t::Array: {
+            if (type->array.size == 0) return sizeof(array_t);
+            return compute_size_na(*type->array.type) * type->array.size;
+        }
         case type_t::Import: throw std::runtime_error("unresolved type");
         }
 

furvm/include/furvm/type.hpp

@@ -5,19 +5,33 @@
 #include "furvm/handle.hpp" // IWYU pragma: keep
 
 #include <cstdint>
+
 namespace furvm {
 
 enum class type_t : std::uint32_t {
     Primitive = 0,
     Reference,
-    List,
+    Array,
 
     Import,
 };
 
 using primitive_type = std::uint64_t;
 using reference_type = type_p;
-using list_type      = type_h;
+
+/**
+ * @brief Array type.
+ */
+struct array_type {
+    type_h type; /**< Type of the array's elements. */
+
+    /**
+     * @brief Size of the array.
+     *
+     * Size of the array. If size is equal to zero, then the array becomes dynamic.
+     */
+    std::size_t size;
+};
 
 struct import_type {
     mod_id  mod;
@@ -29,7 +43,7 @@ struct type {
     union {
         primitive_type primitive;
         reference_type reference;
-        list_type      list;
+        array_type     array;
         import_type    imp;
     };
 
@@ -42,8 +56,11 @@ struct type {
     type(const reference_type& reference)
       : t(type_t::Reference), reference(reference) {}
 
-    type(const list_type& list)
-      : t(type_t::List), list(list) {}
+    type(const type_h& type, std::size_t size = 0)
+      : t(type_t::Array), array(array_type{ type, size }) {}
+
+    type(const array_type& list)
+      : t(type_t::Array), array(list) {}
 
     type(const import_type& imp)
       : t(type_t::Import), imp(imp) {}
@@ -51,7 +68,7 @@ struct type {
     ~type() {
         switch (t) {
         case type_t::Reference: reference.~reference_type(); break;
-        case type_t::List: list.~list_type(); break;
+        case type_t::Array: array.~array_type(); break;
         case type_t::Import: imp.~import_type(); break;
         default: break;
         }
@@ -62,7 +79,7 @@ struct type {
         switch (t) {
         case type_t::Primitive: primitive = other.primitive; break;
         case type_t::Reference: reference = std::move(other.reference); break;
-        case type_t::List: list = std::move(other.list); break;
+        case type_t::Array: array = std::move(other.array); break;
         case type_t::Import: imp = std::move(other.imp); break;
         }
     }
@@ -73,7 +90,7 @@ struct type {
         switch (t) {
         case type_t::Primitive: primitive = other.primitive; break;
         case type_t::Reference: reference = std::move(other.reference); break;
-        case type_t::List: list = std::move(other.list); break;
+        case type_t::Array: array = std::move(other.array); break;
         case type_t::Import: imp = std::move(other.imp); break;
         }
 
@@ -85,7 +102,7 @@ struct type {
         switch (t) {
         case type_t::Primitive: primitive = other.primitive; break;
         case type_t::Reference: reference = other.reference; break;
-        case type_t::List: list = other.list; break;
+        case type_t::Array: array = other.array; break;
         case type_t::Import: imp = other.imp; break;
         }
     }
@@ -96,7 +113,7 @@ struct type {
         switch (t) {
         case type_t::Primitive: primitive = other.primitive; break;
         case type_t::Reference: reference = other.reference; break;
-        case type_t::List: list = other.list; break;
+        case type_t::Array: array = other.array; break;
         case type_t::Import: imp = other.imp; break;
         }
 
@@ -111,9 +128,15 @@ using long_t  = std::int64_t; /**< An 8-byte integer. */
 
 using reference_t = std::byte*;
 
-struct list_t {
-    long_t     size;
-    std::byte* data;
+/**
+ * @brief Array type's data layout.
+ */
+union array_t {
+    std::byte data[]; /**< Static array's elements' data. */
+    struct {
+        long_t     size; /**< Size of the array (in items). */
+        std::byte* data; /**< Pointer to dynamic array's elements' data array. */
+    } dynamic;           /**< Dynamic array's info. */
 };
 
 /**

furvm/src/executor.cpp

@@ -167,8 +167,8 @@ void executor::step() {
         auto ptr   = push_thing({ *m_context->at("core")->type_at(4), m_context, m_context->thing_alloc() });
         switch (furvm::thing<>::resolve_type(thing.type(), m_context)->t) {
         case type_t::Primitive: ptr->get<std::uintptr_t>() = reinterpret_cast<std::uintptr_t>(thing.raw()); break;
-        case type_t::List:
-            ptr->get<std::uintptr_t>() = reinterpret_cast<std::uintptr_t>(thing.get<list_t>().data);
+        case type_t::Array:
+            ptr->get<std::uintptr_t>() = reinterpret_cast<std::uintptr_t>(thing.get<array_t>().data);
             break;
         case type_t::Reference:
         case type_t::Import:
@@ -177,11 +177,14 @@ void executor::step() {
     } break;
     case instruction_t::Sizeof: {
         auto thing = pop_thing()->resolve();
-        auto ptr   = push_thing({ *m_context->at("core")->type_at(3), m_context, m_context->thing_alloc() });
+        auto size  = push_thing({ *m_context->at("core")->type_at(3), m_context, m_context->thing_alloc() });
         auto type  = furvm::thing<>::resolve_type(thing.type(), m_context);
         switch (type->t) {
-        case type_t::Primitive: ptr->get<long_t>() = static_cast<long_t>(type->primitive); break;
-        case type_t::List: ptr->get<long_t>() = thing.get<list_t>().size; break;
+        case type_t::Primitive: size->get<long_t>() = static_cast<long_t>(type->primitive); break;
+        case type_t::Array:
+            size->get<long_t>() =
+                (type->array.size == 0) ? thing.get<array_t>().dynamic.size : static_cast<long_t>(type->array.size);
+            break;
         case type_t::Reference:
         case type_t::Import:
         default: throw std::runtime_error("unreachable");

furvm/src/module.cpp

@@ -58,7 +58,10 @@ std::ostream& mod::serialize(std::ostream& os) const {
         switch (type->t) {
         case type_t::Primitive: detail::serialize(os, type->primitive); break;
         case type_t::Reference: throw std::runtime_error("reference type serialization is unimplemented");
-        case type_t::List: detail::serialize(os, type->list.id()); break;
+        case type_t::Array: {
+            detail::serialize(os, type->array.size);
+            detail::serialize(os, type->array.type.id());
+        } break;
         case type_t::Import: {
             detail::serialize(os, type->imp.mod);
             detail::serialize(os, type->imp.type);
@@ -127,10 +130,12 @@ mod mod::load(std::istream& is) {
             mod.emplace_type(id, std::make_shared<class type>(primitive)).dispatch();
         } break;
         case type_t::Reference: throw std::runtime_error("reference type serialization is unimplemented");
-        case type_t::List: {
+        case type_t::Array: {
+            std::size_t size = 0;
+            detail::load(is, size);
             type_id typeId = 0;
             detail::load(is, typeId);
-            mod.emplace_type(id, std::make_shared<class type>(mod.type_at(typeId))).dispatch();
+            mod.emplace_type(id, std::make_shared<class type>(mod.type_at(typeId), size)).dispatch();
         } break;
         case type_t::Import: {
             std::string modName;