id interface

Signed-off-by: Folling <mail@folling.io>

include/ikarus/stdtypes.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #ifdef __cplusplus
+#include <cstddef>
 #include <cstdint>
 using std::size_t;
 #else

include/ikarus/types/id.h

@@ -6,10 +6,10 @@
 #pragma once
 
 #include <ikarus/macros.h>
+#include <ikarus/stdtypes.h>
 
 IKARUS_BEGIN_HEADER
 
-#include <ikarus/stdtypes.h>
 #include <ikarus/types/object_type.h>
 
 /// \defgroup id Ids
@@ -21,11 +21,13 @@ IKARUS_BEGIN_HEADER
 
 /// \brief A wrapper around a 64 bit integer that represents the id of an object.
 /// \details They are stored as 64 bit integers with the following layout:
-/// - first 8 bits: #IkarusObjectType - 255 possible values, 0 for special values
+/// - first bit: ignored, technically we could use it, but SQLite doesn't support u64 integers.
+///   To avoid ordering fiascos and potential index performance degradation we just skip the first bit.
+/// - next 7 bits: #IkarusObjectType - 127 possible values, 0 for special values
 /// - last 56 bits: incremented counter generated by the database
 struct IkarusId {
     /// \private \brief The value of the id.
-    uint64_t value;
+    int64_t data;
 };
 
 /// \brief A special id returned by failed functions.
@@ -34,9 +36,16 @@ IkarusId const IKARUS_ID_NONE{0};
 IkarusId const IKARUS_ID_UNSPECIFIED{1};
 
 /// \private \brief Generates a new id for the given object type.
-/// \param object_type The type of the object to generate an id for.
+/// \param data The data from which the id will be constructed.
 /// \return The generated id.
-IkarusId ikarus_id_from_integer(IkarusObjectType object_type);
+/// \pre data must be valid under the format described in Id. It should also point to an object in the database.
+IkarusId ikarus_id_from_data(int64_t data);
+
+/// \brief Checkes whether two ids are equal
+/// \param left the left side of the comparison
+/// \param right the right side of the comparison
+/// \return True if the bits from the left id are equal to the bits of the right id
+bool ikarus_id_is_equal(IkarusId left, IkarusId right);
 
 /// \brief Fetches the object type of the given id.
 /// \param id The id to fetch the object type for.

include/ikarus/types/object_type.h

@@ -25,37 +25,37 @@ enum IkarusFolderType {
 /// \remark folders have the first bit set and then mirror the object type of the underlying object
 enum IkarusObjectType {
     /// \brief Not an object or no object.
-    ObjectType_None = 0,
+    IkarusObjectType_None = 0,
     /// \brief An IkarusBlueprint.
-    ObjectType_Blueprint = 0b0000'0001,
+    IkarusObjectType_Blueprint = 0b0000'0001,
     /// \brief An IkarusProperty.
-    ObjectType_Property = 0b0000'0010,
+    IkarusObjectType_Property = 0b0000'0010,
     /// \brief An IkarusEntity.
-    ObjectType_Entity = 0b0000'0011,
+    IkarusObjectType_Entity = 0b0000'0011,
     /// \brief An IkarusBlueprintFolder
-    ObjectType_BlueprintFolder = 0b1000'0001,
+    IkarusObjectType_BlueprintFolder = 0b1000'0001,
     /// \brief An IkarusPropertyFolder
-    ObjectType_PropertyFolder = 0b1000'0010,
+    IkarusObjectType_PropertyFolder = 0b1000'0010,
     /// \brief An IkarusEntityFolder
-    ObjectType_EntityFolder = 0b1000'0011,
+    IkarusObjectType_EntityFolder = 0b1000'0011,
 };
 
 /// \brief A bitset of IkarusObjectType%s.
 enum ObjectTypes {
     /// \brief No object type.
-    ObjectTypes_None = 0,
+    IkarusObjectTypes_None = 0,
     /// \brief An IkarusBlueprint.
-    ObjectTypes_Blueprint = 1 << ObjectType_Blueprint,
+    IkarusObjectTypes_Blueprint = 1 << IkarusObjectType_Blueprint,
     /// \brief An IkarusProperty.
-    ObjectTypes_Property = 1 << ObjectType_Property,
+    IkarusObjectTypes_Property = 1 << IkarusObjectType_Property,
     /// \brief An IkarusEntity.
-    ObjectTypes_Entity = 1 << ObjectType_Entity,
+    IkarusObjectTypes_Entity = 1 << IkarusObjectType_Entity,
     /// \brief An IkarusBlueprintFolder
-    ObjectTypes_BlueprintFolder = 1 << ObjectType_BlueprintFolder,
+    IkarusObjectTypes_BlueprintFolder = 1 << IkarusObjectType_BlueprintFolder,
     /// \brief An IkarusPropertyFolder
-    ObjectTypes_PropertyFolder = 1 << ObjectType_PropertyFolder,
+    IkarusObjectTypes_PropertyFolder = 1 << IkarusObjectType_PropertyFolder,
     /// \brief An IkarusEntityFolder
-    ObjectTypes_EntityFolder = 1 << ObjectType_EntityFolder,
+    IkarusObjectTypes_EntityFolder = 1 << IkarusObjectType_EntityFolder,
 };
 
 // @}

src/types/id.cpp

@@ -0,0 +1,56 @@
+#include "ikarus/types/id.h"
+
+#include <catch2/catch_test_macros.hpp>
+
+IkarusId ikarus_id_from_data(int64_t data) {
+    return IkarusId {
+        .data = data
+    };
+}
+
+IkarusObjectType ikarus_id_get_object_type(IkarusId id) {
+    return static_cast<IkarusObjectType>(id.data >> 56);
+}
+
+bool ikarus_id_is_equal(IkarusId left, IkarusId right) {
+    return left.data == right.data;
+}
+
+bool ikarus_id_is_none(IkarusId id) {
+    return ikarus_id_is_equal(id, IKARUS_ID_NONE);
+}
+
+bool ikarus_id_is_unspecified(IkarusId id) {
+    return ikarus_id_is_equal(id, IKARUS_ID_UNSPECIFIED);
+}
+
+TEST_CASE("id_object_type", "[id]") {
+    auto id = ikarus_id_from_data(static_cast<uint64_t>(IkarusObjectType_Blueprint) << 56);
+
+    REQUIRE(ikarus_id_get_object_type(id) == IkarusObjectType_Blueprint);
+    REQUIRE(!ikarus_id_is_none(id) == IkarusObjectType_Blueprint);
+    REQUIRE(!ikarus_id_is_unspecified(id) == IkarusObjectType_Blueprint);
+}
+
+TEST_CASE("id_equal", "[id]") {
+    auto id = ikarus_id_from_data(static_cast<uint64_t>(IkarusObjectType_Blueprint) << 56);
+    auto copy = id;
+    auto third = ikarus_id_from_data(static_cast<uint64_t>(IkarusObjectType_Property) << 56);
+
+    REQUIRE(ikarus_id_is_equal(id, copy));
+    REQUIRE(!ikarus_id_is_equal(id, third));
+}
+
+TEST_CASE("id_none", "[id]") {
+    auto id = IKARUS_ID_NONE;
+
+    REQUIRE(ikarus_id_is_none(id));
+    REQUIRE(!ikarus_id_is_unspecified(id));
+}
+
+TEST_CASE("id_unspecified", "[id]") {
+    auto id = IKARUS_ID_UNSPECIFIED;
+
+    REQUIRE(!ikarus_id_is_none(id));
+    REQUIRE(ikarus_id_is_unspecified(id));
+}