[core] Check for NaNs in mbgl::util::{min,max,clamp}

7 files changed, 72 insertions, 24 deletions

diff --git a/include/mbgl/util/math.hpp b/include/mbgl/util/math.hpp
index 08625ffc0c..87f9caf478 100644
--- a/include/mbgl/util/math.hpp
+++ b/include/mbgl/util/math.hpp
@@ -3,6 +3,7 @@
 
 #include <cmath>
 #include <array>
+#include <limits>
 
 #include <mbgl/util/vec.hpp>
 
@@ -11,33 +12,33 @@ namespace util {
 
 
 template <typename T>
-inline T max(T a, T b) {
-    return b > a ? b : a;
+typename std::enable_if_t<std::is_integral<T>::value, T> max(T a, T b) {
+    return std::max(a, b);
 }
 
 template <typename T>
-inline T max(T a, T b, T c) {
-    return max(max(a, b), c);
+typename std::enable_if_t<std::is_floating_point<T>::value, T> max(T a, T b) {
+    return std::fmax(a, b);
 }
 
-template <typename T>
-inline T max(T a, T b, T c, T d) {
-    return max(max(a, b), max(c, d));
+template <typename T, typename... Ts>
+typename std::enable_if_t<std::is_arithmetic<T>::value, T> max(T a, T b, Ts... args) {
+    return max(a, max(b, args...));
 }
 
 template <typename T>
-inline T min(T a, T b) {
-    return b < a ? b : a;
+typename std::enable_if_t<std::is_integral<T>::value, T> min(T a, T b) {
+    return std::min(a, b);
 }
 
 template <typename T>
-inline T min(T a, T b, T c) {
-    return min(min(a, b), c);
+typename std::enable_if_t<std::is_floating_point<T>::value, T> min(T a, T b) {
+    return std::fmin(a, b);
 }
 
-template <typename T>
-inline T min(T a, T b, T c, T d) {
-    return min(min(a, b), min(c, d));
+template <typename T, typename... Ts>
+typename std::enable_if_t<std::is_arithmetic<T>::value, T> min(T a, T b, Ts... args) {
+    return min(a, min(b, args...));
 }
 
 // Find the angle of the two vectors, solving the formula for the cross product
@@ -113,8 +114,8 @@ inline S unit(const S& a) {
 }
 
 template <typename T>
-T clamp(T value, T min, T max) {
-    return value < min ? min : (value > max ? max : value);
+T clamp(T value, T min_, T max_) {
+    return max(min_, min(max_, value));
 }
 
 // Constrains n to the given range (including min, excluding max) via modular
diff --git a/include/mbgl/util/projection.hpp b/include/mbgl/util/projection.hpp
index bee5eac8ae..09c8ce74ab 100644
--- a/include/mbgl/util/projection.hpp
+++ b/include/mbgl/util/projection.hpp
@@ -3,6 +3,7 @@
 
 #include <mbgl/util/constants.hpp>
 #include <mbgl/util/geo.hpp>
+#include <mbgl/util/math.hpp>
 
 #include <cmath>
 
@@ -13,16 +14,16 @@ class Projection {
 public:
     static inline double getMetersPerPixelAtLatitude(double lat, double zoom) {
         const double mapPixelWidthAtZoom = std::pow(2.0, zoom) * util::tileSize;
-        const double constrainedLatitude = ::fmin(::fmax(lat, -util::LATITUDE_MAX), util::LATITUDE_MAX);
+        const double constrainedLatitude = util::clamp(lat, -util::LATITUDE_MAX, util::LATITUDE_MAX);
 
         return std::cos(constrainedLatitude * util::DEG2RAD) * util::M2PI * util::EARTH_RADIUS_M / mapPixelWidthAtZoom;
     }
 
     static inline ProjectedMeters projectedMetersForLatLng(const LatLng& latLng) {
-        const double constrainedLatitude = ::fmin(::fmax(latLng.latitude, -util::LATITUDE_MAX), util::LATITUDE_MAX);
+        const double constrainedLatitude = util::clamp(latLng.latitude, -util::LATITUDE_MAX, util::LATITUDE_MAX);
 
         const double m = 1 - 1e-15;
-        const double f = ::fmin(::fmax(std::sin(util::DEG2RAD * constrainedLatitude), -m), m);
+        const double f = util::clamp(std::sin(util::DEG2RAD * constrainedLatitude), -m, m);
 
         const double easting  = util::EARTH_RADIUS_M * latLng.longitude * util::DEG2RAD;
         const double northing = 0.5 * util::EARTH_RADIUS_M * std::log((1 + f) / (1 - f));
@@ -34,7 +35,7 @@ public:
         double latitude = (2 * std::atan(std::exp(projectedMeters.northing / util::EARTH_RADIUS_M)) - (M_PI / 2)) * util::RAD2DEG;
         double longitude = projectedMeters.easting * util::RAD2DEG / util::EARTH_RADIUS_M;
 
-        latitude = ::fmin(::fmax(latitude, -util::LATITUDE_MAX), util::LATITUDE_MAX);
+        latitude = util::clamp(latitude, -util::LATITUDE_MAX, util::LATITUDE_MAX);
 
         return LatLng(latitude, longitude);
     }
diff --git a/src/mbgl/annotation/shape_annotation_impl.cpp b/src/mbgl/annotation/shape_annotation_impl.cpp
index a9277ee0a7..9adebf177b 100644
--- a/src/mbgl/annotation/shape_annotation_impl.cpp
+++ b/src/mbgl/annotation/shape_annotation_impl.cpp
@@ -4,6 +4,7 @@
 #include <mbgl/annotation/annotation_manager.hpp>
 #include <mbgl/annotation/annotation_tile.hpp>
 #include <mbgl/util/constants.hpp>
+#include <mbgl/util/math.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/style/style.hpp>
 #include <mbgl/layer/line_layer.hpp>
@@ -90,8 +91,8 @@ void ShapeAnnotationImpl::updateTile(const TileID& tileID, AnnotationTile& tile)
         std::vector<geojsonvt::LonLat> points;
 
         for (size_t i = 0; i < shape.segments[0].size(); ++i) { // first segment for now (no holes)
-            const double constraintedLatitude = ::fmin(::fmax(shape.segments[0][i].latitude, -util::LATITUDE_MAX), util::LATITUDE_MAX);
-            points.push_back(geojsonvt::LonLat(shape.segments[0][i].longitude, constraintedLatitude));
+            const double constrainedLatitude = util::clamp(shape.segments[0][i].latitude, -util::LATITUDE_MAX, util::LATITUDE_MAX);
+            points.push_back(geojsonvt::LonLat(shape.segments[0][i].longitude, constrainedLatitude));
         }
 
         if (type == geojsonvt::ProjectedFeatureType::Polygon &&
diff --git a/src/mbgl/map/transform.cpp b/src/mbgl/map/transform.cpp
index da085ac750..0c9f7bf1e6 100644
--- a/src/mbgl/map/transform.cpp
+++ b/src/mbgl/map/transform.cpp
@@ -410,6 +410,7 @@ void Transform::scaleBy(double ds, const Duration& duration) {
 }
 
 void Transform::scaleBy(double ds, optional<ScreenCoordinate> anchor, const Duration& duration) {
+    if (std::isnan(ds)) return;
     double scale = util::clamp(state.scale * ds, state.min_scale, state.max_scale);
     setScale(scale, anchor, duration);
 }
diff --git a/src/mbgl/util/geo.cpp b/src/mbgl/util/geo.cpp
index bf7cf38117..7d9db65c4c 100644
--- a/src/mbgl/util/geo.cpp
+++ b/src/mbgl/util/geo.cpp
@@ -1,3 +1,4 @@
+#include <mbgl/util/math.hpp>
 #include <mbgl/util/geo.hpp>
 #include <mbgl/util/constants.hpp>
 #include <mbgl/map/tile_id.hpp>
@@ -13,8 +14,8 @@ LatLng::LatLng(const TileID& id) {
 }
 
 ScreenCoordinate LatLng::project() const {
-    // Clamp to the latitude limits of Mercator.
-    const double constrainedLatitude = ::fmin(::fmax(latitude, -util::LATITUDE_MAX), util::LATITUDE_MAX);
+    // Clamp to the latitude limits of Web Mercator.
+    const double constrainedLatitude = util::clamp(latitude, -util::LATITUDE_MAX, util::LATITUDE_MAX);
 
     // Project a coordinate into unit space in a square map.
     const double sine = std::sin(constrainedLatitude * util::DEG2RAD);
diff --git a/test/test.gypi b/test/test.gypi
index d85faf2f5a..b9ba820e72 100644
--- a/test/test.gypi
+++ b/test/test.gypi
@@ -42,6 +42,7 @@
         'util/geo.cpp',
         'util/image.cpp',
         'util/mapbox.cpp',
+        'util/math.cpp',
         'util/merge_lines.cpp',
         'util/run_loop.cpp',
         'util/text_conversions.cpp',
diff --git a/test/util/math.cpp b/test/util/math.cpp
new file mode 100644
index 0000000000..0074b43509
--- /dev/null
+++ b/test/util/math.cpp
@@ -0,0 +1,42 @@
+#include "../fixtures/util.hpp"
+
+#include <mbgl/util/constants.hpp>
+#include <mbgl/util/math.hpp>
+
+using namespace mbgl;
+
+TEST(Math, MinMaxFloatingPoint) {
+    double minimumValue = std::numeric_limits<double>::min();
+    double lowestValue = std::numeric_limits<double>::lowest();
+    double maximumValue = std::numeric_limits<double>::max();
+    double quietNAN = std::numeric_limits<double>::quiet_NaN();
+
+    ASSERT_DOUBLE_EQ(lowestValue, util::min(minimumValue, lowestValue));
+    ASSERT_DOUBLE_EQ(lowestValue, util::min(double(NAN), lowestValue));
+    ASSERT_DOUBLE_EQ(lowestValue, util::min(quietNAN, lowestValue));
+    ASSERT_DOUBLE_EQ(0., util::min(2., 1., 0.));
+
+    ASSERT_DOUBLE_EQ(maximumValue, util::max(double(NAN), maximumValue));
+    ASSERT_DOUBLE_EQ(maximumValue, util::max(quietNAN, maximumValue));
+    ASSERT_DOUBLE_EQ(10., util::max(8., 9., 10.));
+
+    ASSERT_DOUBLE_EQ(0., util::clamp(0., quietNAN, quietNAN));
+    ASSERT_DOUBLE_EQ(0., util::clamp(0., lowestValue, maximumValue));
+}
+
+TEST(Math, MinMaxIntegral) {
+    int32_t minimumValue = std::numeric_limits<int32_t>::min();
+    int32_t lowestValue = std::numeric_limits<int32_t>::lowest();
+    int32_t maximumValue = std::numeric_limits<int32_t>::max();
+    int32_t quietNAN = std::numeric_limits<int32_t>::quiet_NaN();
+
+    ASSERT_EQ(lowestValue, util::min(minimumValue, lowestValue));
+    ASSERT_EQ(lowestValue, util::min(quietNAN, lowestValue));
+    ASSERT_EQ(0, util::min(2, 1, 0));
+
+    ASSERT_EQ(maximumValue, util::max(quietNAN, maximumValue));
+    ASSERT_EQ(10, util::max(8, 9, 10));
+
+    ASSERT_EQ(0, util::clamp(0, quietNAN, quietNAN));
+    ASSERT_EQ(0, util::clamp(0, lowestValue, maximumValue));
+}