1 files changed, 122 insertions, 0 deletions
diff --git a/platform/default/mbgl/storage/offline.cpp b/platform/default/mbgl/storage/offline.cpp
new file mode 100644
index 0000000000..931e079771
--- /dev/null
+++ b/platform/default/mbgl/storage/offline.cpp
@@ -0,0 +1,122 @@
+#include <mbgl/storage/offline.hpp>
+#include <mbgl/util/tile_cover.hpp>
+#include <mbgl/source/source_info.hpp>
+
+#include <rapidjson/document.h>
+#include <rapidjson/stringbuffer.h>
+#include <rapidjson/writer.h>
+
+#include <cmath>
+
+namespace mbgl {
+
+OfflineTilePyramidRegionDefinition::OfflineTilePyramidRegionDefinition(
+    const std::string& styleURL_, const LatLngBounds& bounds_, double minZoom_, double maxZoom_, float pixelRatio_)
+    : styleURL(styleURL_),
+      bounds(bounds_),
+      minZoom(minZoom_),
+      maxZoom(maxZoom_),
+      pixelRatio(pixelRatio_) {
+    if (minZoom < 0 || maxZoom < 0 || maxZoom < minZoom || pixelRatio < 0 ||
+        !std::isfinite(minZoom) || std::isnan(maxZoom) || !std::isfinite(pixelRatio)) {
+        throw std::invalid_argument("Invalid offline region definition");
+    }
+}
+
+std::vector<TileID> OfflineTilePyramidRegionDefinition::tileCover(SourceType type, uint16_t tileSize, const SourceInfo& info) const {
+    double minZ = std::max<double>(coveringZoomLevel(minZoom, type, tileSize), info.minZoom);
+    double maxZ = std::min<double>(coveringZoomLevel(maxZoom, type, tileSize), info.maxZoom);
+
+    assert(minZ >= 0);
+    assert(maxZ >= 0);
+    assert(minZ < std::numeric_limits<uint8_t>::max());
+    assert(maxZ < std::numeric_limits<uint8_t>::max());
+
+    std::vector<TileID> result;
+
+    for (uint8_t z = minZ; z <= maxZ; z++) {
+        for (const auto& tile : mbgl::tileCover(bounds, z, z)) {
+            result.push_back(tile.normalized());
+        }
+    }
+
+    return result;
+}
+
+OfflineRegionDefinition decodeOfflineRegionDefinition(const std::string& region) {
+    rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> doc;
+    doc.Parse<0>(region.c_str());
+
+    if (doc.HasParseError() ||
+        !doc.HasMember("style_url") || !doc["style_url"].IsString() ||
+        !doc.HasMember("bounds") || !doc["bounds"].IsArray() || doc["bounds"].Size() != 4 ||
+          !doc["bounds"][0].IsDouble() || !doc["bounds"][1].IsDouble() ||
+          !doc["bounds"][2].IsDouble() || !doc["bounds"][3].IsDouble() ||
+        !doc.HasMember("min_zoom") || !doc["min_zoom"].IsDouble() ||
+        (doc.HasMember("max_zoom") && !doc["max_zoom"].IsDouble()) ||
+        !doc.HasMember("pixel_ratio") || !doc["pixel_ratio"].IsDouble()) {
+        throw std::runtime_error("Malformed offline region definition");
+    }
+
+    std::string styleURL { doc["style_url"].GetString(), doc["style_url"].GetStringLength() };
+    LatLngBounds bounds = LatLngBounds::hull(
+        LatLng(doc["bounds"][0].GetDouble(), doc["bounds"][1].GetDouble()),
+        LatLng(doc["bounds"][2].GetDouble(), doc["bounds"][3].GetDouble()));
+    double minZoom = doc["min_zoom"].GetDouble();
+    double maxZoom = doc.HasMember("max_zoom") ? doc["max_zoom"].GetDouble() : INFINITY;
+    float pixelRatio = doc["pixel_ratio"].GetDouble();
+
+    return { styleURL, bounds, minZoom, maxZoom, pixelRatio };
+}
+
+std::string encodeOfflineRegionDefinition(const OfflineRegionDefinition& region) {
+    rapidjson::GenericDocument<rapidjson::UTF8<>, rapidjson::CrtAllocator> doc;
+    doc.SetObject();
+
+    doc.AddMember("style_url", rapidjson::StringRef(region.styleURL.data(), region.styleURL.length()), doc.GetAllocator());
+
+    rapidjson::GenericValue<rapidjson::UTF8<>, rapidjson::CrtAllocator> bounds(rapidjson::kArrayType);
+    bounds.PushBack(region.bounds.south(), doc.GetAllocator());
+    bounds.PushBack(region.bounds.west(), doc.GetAllocator());
+    bounds.PushBack(region.bounds.north(), doc.GetAllocator());
+    bounds.PushBack(region.bounds.east(), doc.GetAllocator());
+    doc.AddMember("bounds", bounds, doc.GetAllocator());
+
+    doc.AddMember("min_zoom", region.minZoom, doc.GetAllocator());
+    if (std::isfinite(region.maxZoom)) {
+        doc.AddMember("max_zoom", region.maxZoom, doc.GetAllocator());
+    }
+
+    doc.AddMember("pixel_ratio", region.pixelRatio, doc.GetAllocator());
+
+    rapidjson::StringBuffer buffer;
+    rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
+    doc.Accept(writer);
+
+    return buffer.GetString();
+}
+
+OfflineRegion::OfflineRegion(int64_t id_,
+                             const OfflineRegionDefinition& definition_,
+                             const OfflineRegionMetadata& metadata_)
+    : id(id_),
+      definition(definition_),
+      metadata(metadata_) {
+}
+
+OfflineRegion::OfflineRegion(OfflineRegion&&) = default;
+OfflineRegion::~OfflineRegion() = default;
+
+const OfflineRegionDefinition& OfflineRegion::getDefinition() const {
+    return definition;
+}
+
+const OfflineRegionMetadata& OfflineRegion::getMetadata() const {
+    return metadata;
+}
+
+int64_t OfflineRegion::getID() const {
+    return id;
+}
+
+} // namespace mbgl