From 02cb3a3fb8b4e6249975503fc2e661f59ad8d045 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Fri, 18 May 2018 14:45:03 -0700
Subject: [PATCH] Thread safety fix for decoding quadkeys to coordinates

---
 projection.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/projection.cpp b/projection.cpp
index 2b63777..a3f2f30 100644
--- a/projection.cpp
+++ b/projection.cpp
@@ -2,6 +2,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <math.h>
+#include <atomic>
 #include "projection.hpp"
 
 struct projection projections[] = {
@@ -107,11 +108,11 @@ unsigned long long encode(unsigned int wx, unsigned int wy) {
 	return out;
 }
 
-static unsigned char decodex[256];
-static unsigned char decodey[256];
+static std::atomic<unsigned char> decodex[256];
+static std::atomic<unsigned char> decodey[256];
 
 void decode(unsigned long long index, unsigned *wx, unsigned *wy) {
-	static int initialized = 0;
+	static std::atomic<int> initialized(0);
 	if (!initialized) {
 		for (size_t ix = 0; ix < 256; ix++) {
 			size_t xx = 0, yy = 0;