Mercurial > hg > ucx / changeset

--- a/CHANGELOG	Fri Oct 10 19:40:24 2025 +0200
+++ b/CHANGELOG	Sat Oct 11 11:55:46 2025 +0200
@@ -28,6 +28,7 @@
  * changes the implementation of cx_strreplacen() for improved efficiency
  * changes all cxListIterator() and cxMapIterator() family of functions to also accept NULL as argument
  * changes insert_element member function of CxList to accept NULL source and return a pointer to the inserted element
+ * changes the compare function wrapper for pointer lists so that it no longer invokes the actual compare function for NULL pointers
  * fixes critical memory overflow in the stack-based array reallocator (this unfortunately breaks the function signature)
  * fixes critical bug in cx_array_insert_sorted() that caused an infinite loop when inserting duplicates
  * fixes mempool implementation not supporting NULL as argument for realloc

--- a/docs/Writerside/topics/about.md	Fri Oct 10 19:40:24 2025 +0200
+++ b/docs/Writerside/topics/about.md	Sat Oct 11 11:55:46 2025 +0200
@@ -55,6 +55,7 @@
 * changes the implementation of cx_strreplacen() for improved efficiency
 * changes all cxListIterator() and cxMapIterator() family of functions to also accept NULL as argument
 * changes insert_element member function of CxList to accept NULL source and return a pointer to the inserted element
+* changes the compare function wrapper for pointer lists so that it no longer invokes the actual compare function for NULL pointers
 * fixes critical memory overflow in the stack-based array reallocator (this unfortunately breaks the function signature)
 * fixes critical bug in cx_array_insert_sorted() that caused an infinite loop when inserting duplicates
 * fixes mempool implementation not supporting NULL as argument for realloc

--- a/src/list.c	Fri Oct 10 19:40:24 2025 +0200
+++ b/src/list.c	Sat Oct 11 11:55:46 2025 +0200
@@ -38,10 +38,18 @@
         const void *l,
         const void *r
 ) {
+    // l and r are guaranteed to be non-NULL pointing to the list's memory
     void *const *lptr = l;
     void *const *rptr = r;
-    const void *left = lptr == NULL ? NULL : *lptr;
-    const void *right = rptr == NULL ? NULL : *rptr;
+    const void *left = *lptr;
+    const void *right = *rptr;
+    if (left == NULL) {
+        // NULL is smaller than any value except NULL
+        return right == NULL ? 0 : -1;
+    } else if (right == NULL) {
+        // any value is larger than NULL
+        return 1;
+    }
     return cx_pl_cmpfunc_impl(left, right);
 }
 
@@ -297,7 +305,10 @@
     for (; i < n; i++) {
         if (NULL == invoke_list_func(
             insert_element, list, index + i,
-            src + (i * elem_size))) return i;
+            src + i * elem_size)
+        ) {
+            return i; // LCOV_EXCL_LINE
+        }
     }
     return i;
 }
@@ -336,7 +347,9 @@
                         si++;
                         inserted++;
                     }
-                    if (inserted == n) return inserted;
+                    if (inserted == n) {
+                        return inserted;
+                    }
                 }
                 continue;
             }
@@ -357,17 +370,22 @@
 
         // insert the elements at location si
         if (ins == 1) {
-            if (NULL == invoke_list_func(
-                insert_element, list, di, src)) return inserted;
+            if (NULL == invoke_list_func(insert_element, list, di, src)) {
+                return inserted; // LCOV_EXCL_LINE
+            }
         } else {
             size_t r = invoke_list_func(insert_array, list, di, src, ins);
-            if (r < ins) return inserted + r;
+            if (r < ins) {
+                return inserted + r;  // LCOV_EXCL_LINE
+            }
         }
         inserted += ins;
         di += ins;
 
         // everything inserted?
-        if (inserted == n) return inserted;
+        if (inserted == n) {
+            return inserted;
+        }
         src = next;
     }
 
@@ -399,7 +417,7 @@
     size_t elem_size = list->collection.elem_size;
     size_t list_size = list->collection.size;
     void *tmp = cxMallocDefault(elem_size * list_size);
-    if (tmp == NULL) abort();
+    if (tmp == NULL) abort(); // LCOV_EXCL_LINE
 
     // copy elements from source array
     char *loc = tmp;
@@ -432,7 +450,7 @@
     size_t elem_size = list->collection.elem_size;
 
     void *tmp = cxMallocDefault(elem_size);
-    if (tmp == NULL) return 1;
+    if (tmp == NULL) return 1; // LCOV_EXCL_LINE
 
     void *ip = invoke_list_func(at, list, i);
     void *jp = invoke_list_func(at, list, j);

--- a/tests/test_list.c	Fri Oct 10 19:40:24 2025 +0200
+++ b/tests/test_list.c	Sat Oct 11 11:55:46 2025 +0200
@@ -1143,18 +1143,24 @@
     CxIterator it2 = cxListBackwardsIterator(list);
     CxIterator it3 = cxListMutIterator(list);
     CxIterator it4 = cxListMutBackwardsIterator(list);
+    CxIterator it5 = cxListMutIteratorAt(list, 0);
+    CxIterator it6 = cxListMutBackwardsIteratorAt(list, 0);
 
     CX_TEST_DO {
         CX_TEST_ASSERT(!cxIteratorValid(it1));
         CX_TEST_ASSERT(!cxIteratorValid(it2));
         CX_TEST_ASSERT(!cxIteratorValid(it3));
         CX_TEST_ASSERT(!cxIteratorValid(it4));
+        CX_TEST_ASSERT(!cxIteratorValid(it5));
+        CX_TEST_ASSERT(!cxIteratorValid(it6));
 
         int c = 0;
         cx_foreach(void*, data, it1) c++;
         cx_foreach(void*, data, it2) c++;
         cx_foreach(void*, data, it3) c++;
         cx_foreach(void*, data, it4) c++;
+        cx_foreach(void*, data, it5) c++;
+        cx_foreach(void*, data, it6) c++;
         CX_TEST_ASSERT(c == 0);
     }
 }
@@ -1220,6 +1226,13 @@
     cxListFree(al);
 }
 
+CX_TEST(test_null_list_free) {
+    CX_TEST_DO {
+        // cannot really verify, but asan or valgrind would complain
+        cxListFree(NULL);
+    }
+}
+
 CX_TEST(test_list_ll_create) {
     CxTestingAllocator talloc;
     cx_testing_allocator_init(&talloc);
@@ -2415,6 +2428,34 @@
     free(testdata);
 })
 
+CX_TEST(test_list_pointer_list_supports_null) {
+    CxList *list = cxLinkedListCreate(cxDefaultAllocator, cx_cmp_int, CX_STORE_POINTERS);
+    int x = 47;
+    int y = 11;
+    int z = 1337;
+    int *nptr = NULL;
+    cxListAdd(list, &x);
+    cxListAdd(list, &y);
+    cxListAdd(list, nptr);
+    cxListAdd(list, &z);
+    CX_TEST_DO {
+        CX_TEST_ASSERT(cxListSize(list) == 4);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 0) == 47);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 1) == 11);
+        CX_TEST_ASSERT((int *) cxListAt(list, 2) == NULL);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 3) == 1337);
+        CX_TEST_ASSERT(cxListFind(list, nptr) == 2);
+
+        // when we sort the list, NULL is supposed to be smaller than any value
+        cxListSort(list);
+        CX_TEST_ASSERT((int *) cxListAt(list, 0) == NULL);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 1) == 11);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 2) == 47);
+        CX_TEST_ASSERT(*(int *) cxListAt(list, 3) == 1337);
+    }
+    cxListFree(list);
+}
+
 CxTestSuite *cx_test_suite_array_list(void) {
     CxTestSuite *suite = cx_test_suite_new("array_list");
 
@@ -2697,6 +2738,15 @@
     cx_test_register(suite, test_empty_list_at);
     cx_test_register(suite, test_empty_list_find);
     cx_test_register(suite, test_empty_list_compare);
+    cx_test_register(suite, test_null_list_free);
 
     return suite;
 }
+
+CxTestSuite *cx_test_suite_list_corner_cases(void) {
+    CxTestSuite *suite = cx_test_suite_new("list corner cases");
+
+    cx_test_register(suite, test_list_pointer_list_supports_null);
+
+    return suite;
+}

--- a/tests/ucxtest.c	Fri Oct 10 19:40:24 2025 +0200
+++ b/tests/ucxtest.c	Sat Oct 11 11:55:46 2025 +0200
@@ -48,6 +48,7 @@
 CxTestSuite *cx_test_suite_linked_list_defaulted_funcs(void);
 CxTestSuite *cx_test_suite_kv_list(void);
 CxTestSuite *cx_test_suite_kv_list_specifics(void);
+CxTestSuite *cx_test_suite_list_corner_cases(void);
 CxTestSuite *cx_test_suite_tree_low_level(void);
 CxTestSuite *cx_test_suite_tree_high_level(void);
 CxTestSuite *cx_test_suite_properties(void);
@@ -101,6 +102,7 @@
             cx_test_suite_linked_list_defaulted_funcs(),
             cx_test_suite_kv_list(),
             cx_test_suite_kv_list_specifics(),
+            cx_test_suite_list_corner_cases(),
             cx_test_suite_tree_low_level(),
             cx_test_suite_tree_high_level(),
             cx_test_suite_properties(),