Modified __safe_add and __safe_sub function in src/count_min_sketch.c (…

…#11) * modified __safe_add and __safe_sub these two function and test it under Ubuntu14.04 LTS with gcc 4.8.4.
barrust · Mar 7, 2019 · 7192c72 · 7192c72
1 parent 81bdf63
commit 7192c72
Showing 1 changed file with 7 additions and 7 deletions.
diff --git a/src/count_min_sketch.c b/src/count_min_sketch.c
@@ -310,16 +310,16 @@ int __compare (const void * a, const void * b) {
 int32_t __safe_add(int a, int b) {
  /* use the gcc macro if compiling with GCC, otherwise, simple overflow check */
  int32_t c = 0;
- #ifdef __GNUC__
+ #if (defined(__GNU__) && __GNUC__ >= 5)
  int bl = __builtin_add_overflow(a, b, &c);
  if (bl != 0) {
  c = INT_MAX;
  }
  #else
- if (b < INT_MIN + a) {
- c = INT_MIN;
+ if (b > INT_MAX - a) {
+ c = INT_MAX;
  } else {
- c = a - b;
+ c = a + b;
  }
  #endif
 
@@ -329,16 +329,16 @@ int32_t __safe_add(int a, int b) {
 int32_t __safe_sub(int32_t a, int32_t b) {
  /* use the gcc macro if compiling with GCC, otherwise, simple overflow check */
  int32_t c = 0;
- #ifdef __GNUC__
+ #if (defined(__GNU__) && __GNUC__ >= 5)
  int32_t bl = __builtin_sub_overflow(a, b, &c);
  if (bl != 0) {
  c = INT_MAX;
  }
  #else
- if (b > INT_MAX - a) {
+ if (b < a - INT_MAX) {
  c = INT_MAX;
  } else {
- c = a + b;
+ c = a - b;
  }
  #endif