From 132508d5cc8ec2403ec2d8ca426d06db6d57f527 Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Sun, 7 Jul 2019 14:44:37 +0900
Subject: [PATCH] Add check for endianness, fix strtoa for ipv4

---
 cpp_impl/src/UDPC_Defines.hpp  |  2 ++
 cpp_impl/src/UDPConnection.cpp | 30 ++++++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/cpp_impl/src/UDPC_Defines.hpp b/cpp_impl/src/UDPC_Defines.hpp
index 5af1f18..3e8f6f0 100644
--- a/cpp_impl/src/UDPC_Defines.hpp
+++ b/cpp_impl/src/UDPC_Defines.hpp
@@ -27,6 +27,8 @@ struct Context {
 
 bool VerifyContext(void *ctx);
 
+bool isBigEndian();
+
 } // namespace UDPC
 
 #endif
diff --git a/cpp_impl/src/UDPConnection.cpp b/cpp_impl/src/UDPConnection.cpp
index 210cabc..f18e4be 100644
--- a/cpp_impl/src/UDPConnection.cpp
+++ b/cpp_impl/src/UDPConnection.cpp
@@ -1,6 +1,9 @@
 #include "UDPC_Defines.hpp"
 #include "UDPConnection.h"
 
+
+#include <optional>
+
 UDPC::Context::Context(bool isThreaded)
     : _contextIdentifier(UDPC_CONTEXT_IDENTIFIER), flags(),
       isAcceptNewConnections(true), protocolID(UDPC_DEFAULT_PROTOCOL_ID),
@@ -29,6 +32,21 @@ bool UDPC::VerifyContext(void *ctx) {
     }
 }
 
+bool UDPC::isBigEndian() {
+    static std::optional<bool> isBigEndian = {};
+    if(isBigEndian) {
+        return *isBigEndian;
+    }
+    union {
+        uint32_t i;
+        char c[4];
+    } bint = { 0x01020304 };
+
+    isBigEndian = (bint.c[0] == 1);
+    return *isBigEndian;
+}
+
+
 void *UDPC_init(uint16_t listenPort, uint32_t listenAddr, int isClient) {
     UDPC::Context *ctx = new UDPC::Context(false);
 
@@ -156,7 +174,11 @@ uint32_t UDPC_strtoa(const char *addrStr) {
             temp *= 10;
             temp += *addrStr - '0';
         } else if (*addrStr == '.' && temp <= 0xFF && index < 3) {
-            addr |= (temp << (8 * index++));
+            if(UDPC::isBigEndian()) {
+                addr |= (temp << (24 - 8 * index++));
+            } else {
+                addr |= (temp << (8 * index++));
+            }
             temp = 0;
         } else {
             return 0;
@@ -165,7 +187,11 @@ uint32_t UDPC_strtoa(const char *addrStr) {
     }
 
     if (index == 3 && temp <= 0xFF) {
-        addr |= temp << 24;
+        if(UDPC::isBigEndian()) {
+            addr |= temp;
+        } else {
+            addr |= temp << 24;
+        }
         return addr;
     } else {
         return 0;