From 75f0e66f1ffde0ca8c9b8d2fbbd7b2981951a300 Mon Sep 17 00:00:00 2001
From: trainstopperd <interglobber@tutanota.com>
Date: Wed, 6 Sep 2023 23:25:37 -0400
Subject: [PATCH] feat: unsigned add checks

---
 src/liberror/public.h        | 27 ++++++++++++++++++++++++++-
 tests/{compile => }/assert.c |  0
 tests/{compile => }/test.c   |  0
 3 files changed, 26 insertions(+), 1 deletion(-)
 rename tests/{compile => }/assert.c (100%)
 rename tests/{compile => }/test.c (100%)

diff --git a/src/liberror/public.h b/src/liberror/public.h
index e74a2b3..71d4897 100755
--- a/src/liberror/public.h
+++ b/src/liberror/public.h
@@ -1,7 +1,7 @@
 #ifndef CWARE_LIBERROR_PUBLIC_H
 #define CWARE_LIBERROR_PUBLIC_H
 
-#if !defined(LIBERROR_NO_SAFETY_CHECKS)
+#ifndef LIBERROR_NO_SAFETY_CHECKS
 #define LIBERROR_ASSERT(expression, type, message, function)                                  \
     do {                                                                                      \
         if((expression) != 0) {                                                               \
@@ -15,10 +15,35 @@
 #define LIBERROR_TEST(expression, message) \
     LIBERROR_ASSERT(expression, "ASSERTION", message, "main")
 
+#define LIBERROR_UNSIGNED_ADD_CHECK(a, b, type, message, function)          \
+    do {                                                                    \
+        /* a + b, where either a or b are zero, can never overflow. */      \
+        if(((a) == 0) || ((b) == 0)) {                                      \
+            break;                                                          \
+        }                                                                   \
+                                                                            \
+        if((a) > (b)) {                                                     \
+            /* a + b is greater or equal to a, so there was no overflow. */ \
+            if(((a) + (b)) >= (a)) {                                        \
+                break;                                                      \
+            }                                                               \
+                                                                            \
+            LIBERROR_ASSERT(1 == 0, type, message, function);               \
+        } else if((a) <= (b)) {                                             \
+            /* a + b is greater or equal to b, so there was no overflow. */ \
+            if(((a) + (b)) >= (b)) {                                        \
+                break;                                                      \
+            }                                                               \
+                                                                            \
+            LIBERROR_ASSERT(1 == 0, type, message, function);
+    } while(0)
+
 #else
 
 #define LIBERROR_ASSERT(expression, message)
 #define LIBERROR_TEST(expression, type, message, function)
+#define LIBERROR_UNSIGNED_ADD_CHECk(a, b, type, message, function)
+
 #endif
 
 #endif
diff --git a/tests/compile/assert.c b/tests/assert.c
similarity index 100%
rename from tests/compile/assert.c
rename to tests/assert.c
diff --git a/tests/compile/test.c b/tests/test.c
similarity index 100%
rename from tests/compile/test.c
rename to tests/test.c