refactor ba_global_alloc and fix coverity issues

Author: bratpiorka

src/base_alloc/base_alloc_global.c

@@ -66,8 +66,6 @@ static void umf_ba_create_global(void) {
 
 // returns index of the allocation class for a given size
 static int size_to_idx(size_t size) {
-    assert(size <= BASE_ALLOC.ac_sizes[NUM_ALLOCATION_CLASSES - 1]);
-
     if (size <= BASE_ALLOC.ac_sizes[0]) {
         return 0;
     }
@@ -77,15 +75,14 @@ static int size_to_idx(size_t size) {
         (int)(log2Utils(size) + !isPowerOf2 - BASE_ALLOC.smallest_ac_size_log2);
 
     assert(index >= 0);
-    assert(index < NUM_ALLOCATION_CLASSES);
-
     return index;
 }
 
 void *umf_ba_global_alloc(size_t size) {
     util_init_once(&ba_is_initialized, umf_ba_create_global);
 
-    if (size > BASE_ALLOC.ac_sizes[NUM_ALLOCATION_CLASSES - 1]) {
+    int ac_index = size_to_idx(size);
+    if (ac_index >= NUM_ALLOCATION_CLASSES) {
 #ifndef NDEBUG
         fprintf(stderr,
                 "base_alloc: allocation size larger than the biggest "
@@ -94,24 +91,16 @@ void *umf_ba_global_alloc(size_t size) {
         return ba_os_alloc(size);
     }
 
-    int ac_index = size_to_idx(size);
-    if (!BASE_ALLOC.ac[ac_index]) {
-        // if creating ac failed, fall back to os allocation
-        fprintf(stderr, "base_alloc: allocation class not created. Falling "
-                        "back to OS memory allocation.\n");
-        return ba_os_alloc(size);
-    }
-
     return umf_ba_alloc(BASE_ALLOC.ac[ac_index]);
 }
 
 void umf_ba_global_free(void *ptr, size_t size) {
-    if (size > BASE_ALLOC.ac_sizes[NUM_ALLOCATION_CLASSES - 1]) {
+    int ac_index = size_to_idx(size);
+    if (ac_index >= NUM_ALLOCATION_CLASSES) {
         ba_os_free(ptr, size);
         return;
     }
 
-    int ac_index = size_to_idx(size);
     if (!BASE_ALLOC.ac[ac_index]) {
         // if creating ac failed, memory must have been allocated by os
         ba_os_free(ptr, size);