fix: remove null checks before free. Reverses commit eb5395b (#643)

* fix: remove null checks before free. Reverses commit eb5395b

* completing the null removal

* updating readme

* adding back some checks.

* lint

README.md

@@ -303,6 +303,21 @@ int main(){
 }
 ```
 
+By default we use:
+```C
+static roaring_memory_t global_memory_hook = {
+    .malloc = malloc,
+    .realloc = realloc,
+    .calloc = calloc,
+    .free = free,
+    .aligned_malloc = roaring_bitmap_aligned_malloc,
+    .aligned_free = roaring_bitmap_aligned_free,
+};
+```
+
+We require that the `free`/`aligned_free` functions follow the C
+convention where `free(NULL)`/`aligned_free(NULL)` have no effect.
+
 
 # Example (C)
 

src/containers/array.c

@@ -145,11 +145,8 @@ int array_container_shrink_to_fit(array_container_t *src) {
 
 /* Free memory. */
 void array_container_free(array_container_t *arr) {
-    if (arr->array !=
-        NULL) {  // Jon Strabala reports that some tools complain otherwise
-        roaring_free(arr->array);
-        arr->array = NULL;  // pedantic
-    }
+    if (arr == NULL) return;
+    roaring_free(arr->array);
     roaring_free(arr);
 }
 
@@ -177,10 +174,7 @@ void array_container_grow(array_container_t *container, int32_t min,
             (uint16_t *)roaring_realloc(array, new_capacity * sizeof(uint16_t));
         if (container->array == NULL) roaring_free(array);
     } else {
-        // Jon Strabala reports that some tools complain otherwise
-        if (array != NULL) {
-            roaring_free(array);
-        }
+        roaring_free(array);
         container->array =
             (uint16_t *)roaring_malloc(new_capacity * sizeof(uint16_t));
     }

src/containers/bitset.c

@@ -130,11 +130,8 @@ void bitset_container_add_from_range(bitset_container_t *bitset, uint32_t min,
 
 /* Free memory. */
 void bitset_container_free(bitset_container_t *bitset) {
-    if (bitset->words !=
-        NULL) {  // Jon Strabala reports that some tools complain otherwise
-        roaring_aligned_free(bitset->words);
-        bitset->words = NULL;  // pedantic
-    }
+    if (bitset == NULL) return;
+    roaring_aligned_free(bitset->words);
     roaring_free(bitset);
 }
 

src/containers/run.c

@@ -189,11 +189,8 @@ void run_container_offset(const run_container_t *c, container_t **loc,
 
 /* Free memory. */
 void run_container_free(run_container_t *run) {
-    if (run->runs !=
-        NULL) {  // Jon Strabala reports that some tools complain otherwise
-        roaring_free(run->runs);
-        run->runs = NULL;  // pedantic
-    }
+    if (run == NULL) return;
+    roaring_free(run->runs);
     roaring_free(run);
 }
 
@@ -211,10 +208,7 @@ void run_container_grow(run_container_t *run, int32_t min, bool copy) {
                                                run->capacity * sizeof(rle16_t));
         if (run->runs == NULL) roaring_free(oldruns);
     } else {
-        // Jon Strabala reports that some tools complain otherwise
-        if (run->runs != NULL) {
-            roaring_free(run->runs);
-        }
+        roaring_free(run->runs);
         run->runs = (rle16_t *)roaring_malloc(run->capacity * sizeof(rle16_t));
     }
     // We may have run->runs == NULL.