[core] Distance expression: Change template class into template function in geometry_util, add range assertion for distance contaniner IndexRange

Change distance units to small letters, update tests accordingly

2 files changed, 58 insertions, 82 deletions

diff --git a/src/mbgl/style/expression/distance.cpp b/src/mbgl/style/expression/distance.cpp
index c4d0c7b56d..d42cfa39ea 100644
--- a/src/mbgl/style/expression/distance.cpp
+++ b/src/mbgl/style/expression/distance.cpp
@@ -24,20 +24,6 @@ namespace {
 const std::size_t MinPointsSize = 100;
 const std::size_t MinLinePointsSize = 50;
 
-using BBox = std::array<double, 4>;
-const BBox DefaultBBox = BBox{std::numeric_limits<double>::infinity(),
-                              std::numeric_limits<double>::infinity(),
-                              -std::numeric_limits<double>::infinity(),
-                              -std::numeric_limits<double>::infinity()};
-
-// bbox[minX, minY, maxX, maxY]
-void updateBBox(BBox& bbox, const mapbox::geometry::point<double>& p) {
-    bbox[0] = std::min(p.x, bbox[0]);
-    bbox[1] = std::min(p.y, bbox[1]);
-    bbox[2] = std::max(p.x, bbox[2]);
-    bbox[3] = std::max(p.y, bbox[3]);
-}
-
 // Inclusive index range for multipoint or linestring container
 using IndexRange = std::pair<std::size_t, std::size_t>;
 
@@ -45,16 +31,20 @@ std::size_t getRangeSize(const IndexRange& range) {
     return range.second - range.first + 1;
 }
 
-BBox getBBox(const mapbox::geometry::multi_point<double>& points, const IndexRange& range) {
-    BBox bbox = DefaultBBox;
+using DistanceBBox = GeometryBBox<double>;
+
+DistanceBBox getBBox(const mapbox::geometry::multi_point<double>& points, const IndexRange& range) {
+    assert(range.second >= range.first && range.second < points.size());
+    DistanceBBox bbox = DefaultDistanceBBox;
     for (std::size_t i = range.first; i <= range.second; ++i) {
         updateBBox(bbox, points[i]);
     }
     return bbox;
 }
 
-BBox getBBox(const mapbox::geometry::line_string<double>& line, const IndexRange& range) {
-    BBox bbox = DefaultBBox;
+DistanceBBox getBBox(const mapbox::geometry::line_string<double>& line, const IndexRange& range) {
+    assert(range.second >= range.first && range.second < line.size());
+    DistanceBBox bbox = DefaultDistanceBBox;
     for (std::size_t i = range.first; i <= range.second; ++i) {
         updateBBox(bbox, line[i]);
     }
@@ -62,11 +52,13 @@ BBox getBBox(const mapbox::geometry::line_string<double>& line, const IndexRange
 }
 
 // Calculate the distance between two bounding boxes.
-// Calculate the delta in x and y direction, and use two fake points {0, 0} and {dx, dy} to calculate the distance.
-// Distance will be 0 if bounding box are overlapping.
-double bboxToBBoxDistance(const BBox& bbox1, const BBox& bbox2, mapbox::cheap_ruler::CheapRuler& ruler) {
-    double dx = 0.;
-    double dy = 0.;
+// Calculate the delta in x and y direction, and use two fake points {0.0, 0.0} and {dx, dy} to calculate the distance.
+// Distance will be 0.0 if bounding box are overlapping.
+double bboxToBBoxDistance(const DistanceBBox& bbox1,
+                          const DistanceBBox& bbox2,
+                          mapbox::cheap_ruler::CheapRuler& ruler) {
+    double dx = 0.0;
+    double dy = 0.0;
     // bbox1 in left side
     if (bbox1[2] < bbox2[0]) {
         dx = bbox2[0] - bbox1[2];
@@ -83,7 +75,7 @@ double bboxToBBoxDistance(const BBox& bbox1, const BBox& bbox2, mapbox::cheap_ru
     if (bbox1[3] < bbox2[1]) {
         dy = bbox2[1] - bbox1[3];
     }
-    return ruler.distance(mapbox::geometry::point<double>{0., 0.}, mapbox::geometry::point<double>{dx, dy});
+    return ruler.distance(mapbox::geometry::point<double>{0.0, 0.0}, mapbox::geometry::point<double>{dx, dy});
 }
 
 double pointToLineDistance(const mapbox::geometry::point<double>& point,
@@ -98,6 +90,8 @@ double lineToLineDistance(const mapbox::geometry::line_string<double>& line1,
                           const mapbox::geometry::line_string<double>& line2,
                           IndexRange& range2,
                           mapbox::cheap_ruler::CheapRuler& ruler) {
+    assert(range1.second >= range1.first && range1.second < line1.size());
+    assert(range2.second >= range2.first && range2.second < line2.size());
     double dist = std::numeric_limits<double>::infinity();
     for (std::size_t i = range1.first; i < range1.second; ++i) {
         const auto& p1 = line1[i];
@@ -105,7 +99,7 @@ double lineToLineDistance(const mapbox::geometry::line_string<double>& line1,
         for (std::size_t j = range2.first; j < range2.second; ++j) {
             const auto& q1 = line2[j];
             const auto& q2 = line2[j + 1];
-            if (GeometryUtil<double>::segmentIntersectSegment(p1, p2, q1, q2)) return 0.;
+            if (segmentIntersectSegment(p1, p2, q1, q2)) return 0.0;
             auto dist1 = std::min(pointToLineDistance(p1, mapbox::geometry::line_string<double>{q1, q2}, ruler),
                                   pointToLineDistance(p2, mapbox::geometry::line_string<double>{q1, q2}, ruler));
             auto dist2 = std::min(pointToLineDistance(q1, mapbox::geometry::line_string<double>{p1, p2}, ruler),
@@ -121,11 +115,13 @@ double pointsToPointsDistance(const mapbox::geometry::multi_point<double>& point
                               const mapbox::geometry::multi_point<double>& points2,
                               IndexRange& range2,
                               mapbox::cheap_ruler::CheapRuler& ruler) {
+    assert(range1.second >= range1.first && range1.second < points1.size());
+    assert(range2.second >= range2.first && range2.second < points2.size());
     double dist = std::numeric_limits<double>::infinity();
     for (std::size_t i = range1.first; i <= range1.second; ++i) {
         for (std::size_t j = range2.first; j <= range2.second; ++j) {
             dist = std::min(dist, ruler.distance(points1[i], points2[j]));
-            if (dist == 0.) return dist;
+            if (dist == 0.0) return dist;
         }
     }
     return dist;
@@ -154,8 +150,7 @@ std::pair<mbgl::optional<IndexRange>, mbgl::optional<IndexRange>> splitRange(con
 
 // <distance, range1, range2>
 using DistPair = std::tuple<double, IndexRange, IndexRange>;
-class Comparator {
-public:
+struct Comparator {
     bool operator()(DistPair& left, DistPair& right) { return std::get<0>(left) < std::get<0>(right); }
 };
 // The priority queue will ensure the top element would always be the pair that has the biggest distance
@@ -180,7 +175,7 @@ double lineToLineDistance(const mapbox::geometry::line_string<double>& line1,
         // In case the set size are relatively small, we could use brute-force directly
         if (getRangeSize(rangeA) <= MinLinePointsSize && getRangeSize(rangeB) <= MinLinePointsSize) {
             miniDist = std::min(miniDist, lineToLineDistance(line1, rangeA, line2, rangeB, ruler));
-            if (miniDist == 0.) return 0.;
+            if (miniDist == 0.0) return 0.0;
         } else {
             auto newRangesA = splitRange(rangeA, true /*isLine*/);
             auto newRangesB = splitRange(rangeB, true /*isLine*/);
@@ -223,7 +218,7 @@ double pointsToPointsDistance(const mapbox::geometry::multi_point<double>& point
         // In case the set size are relatively small, we could use brute-force directly
         if (getRangeSize(rangeA) <= MinPointsSize && getRangeSize(rangeB) <= MinPointsSize) {
             miniDist = std::min(miniDist, pointsToPointsDistance(pointSet1, rangeA, pointSet2, rangeB, ruler));
-            if (miniDist == 0.) return 0.;
+            if (miniDist == 0.0) return 0.0;
         } else {
             auto newRangesA = splitRange(rangeA, false /*isLine*/);
             auto newRangesB = splitRange(rangeB, false /*isLine*/);
@@ -263,11 +258,13 @@ double pointsToLineDistance(const mapbox::geometry::multi_point<double>& points,
 
         // In case the set size are relatively small, we could use brute-force directly
         if (getRangeSize(rangeA) <= MinPointsSize && getRangeSize(rangeB) <= MinLinePointsSize) {
+            assert(rangeA.second >= rangeA.first && rangeA.second < points.size());
+            assert(rangeB.second >= rangeB.first && rangeB.second < line.size());
             auto subLine =
                 mapbox::geometry::multi_point<double>(line.begin() + rangeB.first, line.begin() + rangeB.second + 1);
             for (std::size_t i = rangeA.first; i <= rangeA.second; ++i) {
                 miniDist = std::min(miniDist, pointToLineDistance(points[i], subLine, ruler));
-                if (miniDist == 0.) return 0.;
+                if (miniDist == 0.0) return 0.0;
             }
         } else {
             auto newRangesA = splitRange(rangeA, false /*isLine*/);
@@ -296,7 +293,7 @@ double pointsToLinesDistance(const mapbox::geometry::multi_point<double>& points
     double dist = std::numeric_limits<double>::infinity();
     for (const auto& line : lines) {
         dist = std::min(dist, pointsToLineDistance(points, line, ruler));
-        if (dist == 0.) return dist;
+        if (dist == 0.0) return 0.0;
     }
     return dist;
 }
@@ -307,7 +304,7 @@ double lineToLinesDistance(const mapbox::geometry::line_string<double>& line,
     double dist = std::numeric_limits<double>::infinity();
     for (const auto& l : lines) {
         dist = std::min(dist, lineToLineDistance(line, l, ruler));
-        if (dist == 0.) return dist;
+        if (dist == 0.0) return 0.0;
     }
     return dist;
 }
@@ -372,7 +369,7 @@ double calculateDistance(const GeometryTileFeature& feature,
                 double dist = std::numeric_limits<double>::infinity();
                 for (const auto& line : lines) {
                     dist = std::min(dist, lineToGeometryDistance(line, geoSet, unit));
-                    if (dist == 0.) return dist;
+                    if (dist == 0.0) return dist;
                 }
                 return dist;
             },
@@ -405,24 +402,24 @@ optional<Arguments> parseValue(const style::conversion::Convertible& value, styl
                 ctx.error("Failed to parse unit argument from 'distance' expression");
                 return nullopt;
             }
-            if (*input == "Meters" || *input == "Metres") {
+            if (*input == "meters" || *input == "metres") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Meters;
-            } else if (*input == "Kilometers") {
+            } else if (*input == "kilometers") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Kilometers;
-            } else if (*input == "Miles") {
+            } else if (*input == "miles") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Miles;
-            } else if (*input == "NauticalMiles") {
+            } else if (*input == "nauticalmiles") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::NauticalMiles;
-            } else if (*input == "Yards") {
+            } else if (*input == "yards") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Yards;
-            } else if (*input == "Feet") {
+            } else if (*input == "feet") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Feet;
-            } else if (*input == "Inches") {
+            } else if (*input == "inches") {
                 unit = mapbox::cheap_ruler::CheapRuler::Unit::Inches;
             } else {
                 ctx.error(
-                    "'distance' expression only accepts following Units:  'Kilometers', 'Miles', 'NauticalMiles', "
-                    "'Meters', 'Metres', 'Yards', 'Feet', 'Inches'.");
+                    "'distance' expression only accepts following units: kilometers, miles, nauticalmiles, "
+                    "meters, metres, yards, feet, inches.");
                 return nullopt;
             }
         }
@@ -438,8 +435,8 @@ optional<Arguments> parseValue(const style::conversion::Convertible& value, styl
         }
     }
     ctx.error(
-        "'distance' expression needs to be an array with format [\"Distance\", GeoJSONObj, \"unit(optional, Meters by "
-        "default)\"].");
+        "'distance' expression needs to be an array with format [\"Distance\", GeoJSONObj, \"units\"(\"units\" is an "
+        "optional argument, 'meters' will be used by default)].");
     return nullopt;
 }
 
@@ -474,6 +471,7 @@ EvaluationResult Distance::evaluate(const EvaluationContext& params) const {
     if (geometryType == FeatureType::Point || geometryType == FeatureType::LineString) {
         auto distance = calculateDistance(*params.feature, *params.canonical, geometries, unit);
         if (!std::isnan(distance)) {
+            assert(distance >= 0.0);
             return distance;
         }
     }
@@ -547,21 +545,21 @@ Value convertValue(const mapbox::geojson::rapidjson_value& v) {
 std::string getUnits(const mapbox::cheap_ruler::CheapRuler::Unit& unit) {
     switch (unit) {
         case mapbox::cheap_ruler::CheapRuler::Kilometers:
-            return "Kilometers";
+            return "kilometers";
         case mapbox::cheap_ruler::CheapRuler::Miles:
-            return "Miles";
+            return "miles";
         case mapbox::cheap_ruler::CheapRuler::NauticalMiles:
-            return "NauticalMiles";
+            return "nauticalmiles";
         case mapbox::cheap_ruler::CheapRuler::Meters:
-            return "Meters";
+            return "meters";
         case mapbox::cheap_ruler::CheapRuler::Yards:
-            return "Yards";
+            return "yards";
         case mapbox::cheap_ruler::CheapRuler::Feet:
-            return "Feet";
+            return "feet";
         case mapbox::cheap_ruler::CheapRuler::Inches:
-            return "Inches";
+            return "inches";
         default:
-            return "Error";
+            return "error";
     }
 }
 
diff --git a/src/mbgl/style/expression/within.cpp b/src/mbgl/style/expression/within.cpp
index a3e2500319..3fd2bf8f92 100644
--- a/src/mbgl/style/expression/within.cpp
+++ b/src/mbgl/style/expression/within.cpp
@@ -15,29 +15,6 @@
 namespace mbgl {
 namespace {
 
-// contains minX, minY, maxX, maxY
-using WithinBBox = std::array<int64_t, 4>;
-const WithinBBox DefaultBBox = WithinBBox{std::numeric_limits<int64_t>::max(),
-                                          std::numeric_limits<int64_t>::max(),
-                                          std::numeric_limits<int64_t>::min(),
-                                          std::numeric_limits<int64_t>::min()};
-
-// check if bbox1 is within bbox2
-void updateBBox(WithinBBox& bbox, const Point<int64_t>& p) {
-    bbox[0] = std::min(p.x, bbox[0]);
-    bbox[1] = std::min(p.y, bbox[1]);
-    bbox[2] = std::max(p.x, bbox[2]);
-    bbox[3] = std::max(p.y, bbox[3]);
-}
-
-bool boxWithinBox(const WithinBBox& bbox1, const WithinBBox& bbox2) {
-    if (bbox1[0] <= bbox2[0]) return false;
-    if (bbox1[2] >= bbox2[2]) return false;
-    if (bbox1[1] <= bbox2[1]) return false;
-    if (bbox1[3] >= bbox2[3]) return false;
-    return true;
-}
-
 Point<int64_t> latLonToTileCoodinates(const Point<double>& point, const mbgl::CanonicalTileID& canonical) {
     const double size = util::EXTENT * std::pow(2, canonical.z);
 
@@ -53,6 +30,7 @@ Point<int64_t> latLonToTileCoodinates(const Point<double>& point, const mbgl::Ca
     return p;
 };
 
+using WithinBBox = GeometryBBox<int64_t>;
 Polygon<int64_t> getTilePolygon(const Polygon<double>& polygon,
                                 const mbgl::CanonicalTileID& canonical,
                                 WithinBBox& bbox) {
@@ -149,7 +127,7 @@ MultiLineString<int64_t> getTileLines(const GeometryCollection& lines,
 
     const auto worldSize = util::EXTENT * std::pow(2, canonical.z);
     if (bbox[2] - bbox[0] <= worldSize / 2) {
-        bbox = DefaultBBox;
+        bbox = DefaultWithinBBox;
         for (auto& line : results) {
             for (auto& p : line) {
                 updatePoint(p, bbox, polyBBox, worldSize);
@@ -162,28 +140,28 @@ MultiLineString<int64_t> getTileLines(const GeometryCollection& lines,
 bool featureWithinPolygons(const GeometryTileFeature& feature,
                            const CanonicalTileID& canonical,
                            const Feature::geometry_type& polygonGeoSet) {
-    WithinBBox polyBBox = DefaultBBox;
+    WithinBBox polyBBox = DefaultWithinBBox;
     const auto polygons = getTilePolygons(polygonGeoSet, canonical, polyBBox);
     assert(!polygons.empty());
     const GeometryCollection& geometries = feature.getGeometries();
     switch (feature.getType()) {
         case FeatureType::Point: {
             assert(!geometries.empty());
-            WithinBBox pointBBox = DefaultBBox;
+            WithinBBox pointBBox = DefaultWithinBBox;
             MultiPoint<int64_t> points = getTilePoints(geometries.at(0), canonical, pointBBox, polyBBox);
             if (!boxWithinBox(pointBBox, polyBBox)) return false;
 
             return std::all_of(points.begin(), points.end(), [&polygons](const auto& p) {
-                return GeometryUtil<int64_t>::pointWithinPolygons(p, polygons);
+                return pointWithinPolygons<int64_t>(p, polygons);
             });
         }
         case FeatureType::LineString: {
-            WithinBBox lineBBox = DefaultBBox;
+            WithinBBox lineBBox = DefaultWithinBBox;
             MultiLineString<int64_t> multiLineString = getTileLines(geometries, canonical, lineBBox, polyBBox);
             if (!boxWithinBox(lineBBox, polyBBox)) return false;
 
             return std::all_of(multiLineString.begin(), multiLineString.end(), [&polygons](const auto& line) {
-                return GeometryUtil<int64_t>::lineStringWithinPolygons(line, polygons);
+                return lineStringWithinPolygons<int64_t>(line, polygons);
             });
         }
         default: