add macOS implementation

macos/include/uberz/WritableArchive.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef UBERZ_WRITABLE_ARCHIVE_H
+#define UBERZ_WRITABLE_ARCHIVE_H
+
+#include <filament/MaterialEnums.h>
+
+#include <uberz/ArchiveEnums.h>
+#include <utils/FixedCapacityVector.h>
+#include <utils/CString.h>
+
+#include <string_view>
+
+#include <tsl/robin_map.h>
+
+namespace filament::uberz {
+
+// Precompiled set of materials bundled with a list of features flags that each material supports.
+// This is the writeable counterpart to ReadableArchive.
+// Users do not need to access this class directly, they should go through gltfio.
+class WritableArchive {
+public:
+    WritableArchive(size_t materialCount) : mMaterials(uint32_t(materialCount)) {
+        assert(materialCount <= UINT_MAX);
+    }
+
+    void addMaterial(const char* name, const uint8_t* package, size_t packageSize);
+    void addSpecLine(std::string_view line);
+    utils::FixedCapacityVector<uint8_t> serialize() const;
+
+    // Low-level alternatives to addSpecLine that do not involve parsing:
+    void setShadingModel(Shading sm);
+    void setBlendingModel(BlendingMode bm);
+    void setFeatureFlag(const char* key, ArchiveFeature value);
+
+private:
+    size_t mLineNumber = 1;
+    ssize_t mMaterialIndex = -1;
+
+    struct Material {
+        utils::CString name;
+        utils::FixedCapacityVector<uint8_t> package;
+        Shading shadingModel;
+        BlendingMode blendingMode;
+        tsl::robin_map<utils::CString, ArchiveFeature, utils::CString::Hasher> flags;
+    };
+
+    utils::FixedCapacityVector<Material> mMaterials;
+};
+
+} // namespace filament::uberz
+
+#endif // UBERZ_WRITABLE_ARCHIVE_H