From cedda5ef4f73fccfc795e6bc48b368e48f11ad8d Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Wed, 10 Jan 2018 11:48:06 -0800
Subject: [core] Handle NaN input to interpolate and step

---
 src/mbgl/style/expression/step.cpp  |  9 ++++++++-
 src/mbgl/style/expression/value.cpp | 10 +++-------
 2 files changed, 11 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/mbgl/style/expression/step.cpp b/src/mbgl/style/expression/step.cpp
index bfcb6fd270..11bf543b76 100644
--- a/src/mbgl/style/expression/step.cpp
+++ b/src/mbgl/style/expression/step.cpp
@@ -2,6 +2,7 @@
 #include <mbgl/style/expression/get_covering_stops.hpp>
 #include <mbgl/util/string.hpp>
 
+#include <cmath>
 
 namespace mbgl {
 namespace style {
@@ -9,8 +10,14 @@ namespace expression {
 
 EvaluationResult Step::evaluate(const EvaluationContext& params) const {
     const EvaluationResult evaluatedInput = input->evaluate(params);
-    if (!evaluatedInput) { return evaluatedInput.error(); }
+    if (!evaluatedInput) {
+        return evaluatedInput.error();
+    }
+
     float x = *fromExpressionValue<float>(*evaluatedInput);
+    if (std::isnan(x)) {
+        return EvaluationError { "Input is not a number." };
+    }
 
     if (stops.empty()) {
         return EvaluationError { "No stops in step curve." };
diff --git a/src/mbgl/style/expression/value.cpp b/src/mbgl/style/expression/value.cpp
index b75f471ce3..ef4769df02 100644
--- a/src/mbgl/style/expression/value.cpp
+++ b/src/mbgl/style/expression/value.cpp
@@ -108,13 +108,9 @@ Value ValueConverter<float>::toExpressionValue(const float value) {
 }
 
 optional<float> ValueConverter<float>::fromExpressionValue(const Value& value) {
-    if (value.template is<double>()) {
-        double v = value.template get<double>();
-        if (v <= std::numeric_limits<float>::max()) {
-            return static_cast<float>(v);
-        }
-    }
-    return optional<float>();
+    return value.template is<double>()
+        ? static_cast<float>(value.template get<double>())
+        : optional<float>();
 }
 
 
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