From 998bacf3753e5f2573649d2083089ab4ba806bcc Mon Sep 17 00:00:00 2001
From: Samuel Neves <sneves@dei.uc.pt>
Date: Tue, 17 May 2016 21:40:56 +0100
Subject: [PATCH] don't crash on Win32

---
 src/libsodium/sodium/core.c | 41 +++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/src/libsodium/sodium/core.c b/src/libsodium/sodium/core.c
index ad48bd20..dcfd8ff7 100644
--- a/src/libsodium/sodium/core.c
+++ b/src/libsodium/sodium/core.c
@@ -76,33 +76,44 @@ _sodium_crit_leave(void)
 
 #elif defined(_WIN32)
 
-static CRITICAL_SECTION *_sodium_lock;
+static CRITICAL_SECTION  _sodium_lock;
 static volatile LONG     _sodium_lock_initialized;
 
+static int
+_sodium_crit_init(void)
+{
+    LONG status = 0L;
+
+    while ((status = InterlockedCompareExchange(&_sodium_lock_initialized,
+                                                1L, 0L)) == 1L) {
+        Sleep(0);
+    }
+
+    switch(status) {
+    case 0L:
+        InitializeCriticalSection(&_sodium_lock);
+        return InterlockedExchange(&_sodium_lock_initialized, 2L) == 1L ? 0 : -1;
+    case 2L:
+        return 0;
+    default: /* should never be reached */
+        return -1;
+    }
+}
+
 static int
 _sodium_crit_enter(void)
 {
-    if (InterlockedCompareExchange(&_sodium_lock_initialized,
-                                   1L, 0L) == 0L) {
-        InitializeCriticalSection(_sodium_lock);
-        InterlockedIncrement(&_sodium_lock_initialized);
-    } else {
-        while (InterlockedCompareExchange(&_sodium_lock_initialized,
-                                          2L, 2L) != 2L) {
-            Sleep(0);
-        }
+    if(_sodium_crit_init() != 0) {
+        return -1;
     }
+    EnterCriticalSection(&_sodium_lock);
     return 0;
 }
 
 static int
 _sodium_crit_leave(void)
 {
-    if (_sodium_lock == NULL) {
-        return -1;
-    }
-    LeaveCriticalSection(_sodium_lock);
-
+    LeaveCriticalSection(&_sodium_lock);
     return 0;
 }