From e4a9e5db575c818f9ccd0c4e23237ced5b3af5a4 Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Sat, 7 Jul 2018 09:16:50 +1000
Subject: [PATCH] Fix crashes when using an empty index

---
 include/kdbush.hpp | 4 ++++
 test.cpp           | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/include/kdbush.hpp b/include/kdbush.hpp
index d343b2b..be68ec5 100644
--- a/include/kdbush.hpp
+++ b/include/kdbush.hpp
@@ -94,6 +94,8 @@ class KDBush {
                const TIndex right,
                const std::uint8_t axis) {
 
+        if (points.empty()) return;
+
         if (right - left <= nodeSize) {
             for (auto i = left; i <= right; i++) {
                 const TNumber x = std::get<0>(points[i]);
@@ -125,6 +127,8 @@ class KDBush {
                 const TIndex right,
                 const std::uint8_t axis) {
 
+        if (points.empty()) return;
+
         const TNumber r2 = r * r;
 
         if (right - left <= nodeSize) {
diff --git a/test.cpp b/test.cpp
index f31a1ab..b9d6e54 100644
--- a/test.cpp
+++ b/test.cpp
@@ -45,6 +45,12 @@ static void testRadius() {
 static void testEmpty() {
     auto emptyPoints = std::vector<TPoint>{};
     kdbush::KDBush<TPoint> index(emptyPoints);
+    // test no crash when using empty index
+    TIds result;
+    index.within(50, 50, 20, [&result](const auto id) { result.push_back(id); });
+    assert(result.empty());
+    index.range(20, 30, 50, 70, [&result](const auto id) { result.push_back(id); });
+    assert(result.empty());
 }
 
 int main() {