Trade: add SceneData::fieldSizeBound().

Like mappingBound(), but instead of giving an upper bound for object
count, gives an upper bound for field size.

src/Magnum/Trade/SceneData.cpp

@@ -851,6 +851,13 @@ Containers::StridedArrayView1D<const void> SceneData::fieldDataFieldViewInternal
     return fieldDataFieldViewInternal(field, 0, field._size);
 }
 
+std::size_t SceneData::fieldSizeBound() const {
+    std::size_t out = 0;
+    for(const SceneFieldData& i: _fields)
+        out = Math::max(out, std::size_t(i._size));
+    return out;
+}
+
 SceneFieldData SceneData::fieldData(const UnsignedInt id) const {
     CORRADE_ASSERT(id < _fields.size(),
         "Trade::SceneData::fieldData(): index" << id << "out of range for" << _fields.size() << "fields", SceneFieldData{});

src/Magnum/Trade/SceneData.h

@@ -1304,6 +1304,11 @@ class MAGNUM_TRADE_EXPORT SceneData {
          * @m_since_latest
          *
          * Upper bound on object mapping indices of all fields in the scene.
+         * Note that an object can have a certain field associated with
+         * it multiple times with different values (for example an object
+         * having multiple meshes), and thus a field size can be larger than
+         * @ref mappingBound() --- see @ref fieldSizeBound() for an upper
+         * bound for all field sizes.
          * @see @ref fieldCount(), @ref fieldSize()
          */
         UnsignedLong mappingBound() const { return _mappingBound; }
@@ -1320,6 +1325,18 @@ class MAGNUM_TRADE_EXPORT SceneData {
          */
         UnsignedInt fieldCount() const { return _fields.size(); }
 
+        /**
+         * @brief Field size bound
+         * @m_since_latest
+         *
+         * A maximum of all @ref fieldSize() or @cpp 0 @ce for a scene with no
+         * fields. Note that an object can have a certain field associated with
+         * it multiple times with different values (for example an object
+         * having multiple meshes), and thus a field size can be larger than
+         * @ref mappingBound().
+         */
+        std::size_t fieldSizeBound() const;
+
         /**
          * @brief Raw field metadata
          * @m_since_latest

src/Magnum/Trade/Test/SceneDataTest.cpp

@@ -1367,6 +1367,7 @@ void SceneDataTest::construct() {
     CORRADE_COMPARE(scene.mappingBound(), 8);
     CORRADE_COMPARE(scene.mappingType(), SceneMappingType::UnsignedShort);
     CORRADE_COMPARE(scene.fieldCount(), 4);
+    CORRADE_COMPARE(scene.fieldSizeBound(), 5);
     CORRADE_COMPARE(scene.importerState(), &importerState);
 
     /* is2D() / is3D() exhaustively tested in transformations*DAsArray[TRS]()
@@ -1608,6 +1609,7 @@ void SceneDataTest::constructZeroFields() {
     CORRADE_COMPARE(scene.mappingBound(), 37563);
     CORRADE_COMPARE(scene.mappingType(), SceneMappingType::UnsignedShort);
     CORRADE_COMPARE(scene.fieldCount(), 0);
+    CORRADE_COMPARE(scene.fieldSizeBound(), 0);
     CORRADE_VERIFY(!scene.is2D());
     CORRADE_VERIFY(!scene.is3D());
 }
@@ -1626,6 +1628,7 @@ void SceneDataTest::constructZeroObjects() {
     CORRADE_COMPARE(scene.mappingBound(), 0);
     CORRADE_COMPARE(scene.mappingType(), SceneMappingType::UnsignedInt);
     CORRADE_COMPARE(scene.fieldCount(), 2);
+    CORRADE_COMPARE(scene.fieldSizeBound(), 0);
 
     /* Field property access by name */
     CORRADE_COMPARE(scene.fieldType(SceneField::Mesh), SceneFieldType::UnsignedShort);