add allocator accessors

Adds functions to retrieve the functions used for
memory allocation (malloc, realloc, and free).

include/stumpless/memory.h

@@ -184,6 +184,66 @@ void *
 ( *stumpless_set_realloc( void * ( *realloc_func ) ( void *, size_t) ) )
 ( void *, size_t );
 
+/**
+ * Retrieves the current malloc function used by the library.
+ *
+ * **Thread Safety: MT-Safe**
+ * This function is thread-safe as it does not modify any global state.
+ * It simply retrieves a pointer to the current memory allocation function.
+ *
+ * **Async Signal Safety: AS-Safe**
+ * This function is safe to call from signal handlers since it does not
+ * cause any side effects or modify state.
+ *
+ * **Async Cancel Safety: AC-Safe**
+ * This function is safe to call from threads that may be asynchronously
+ * cancelled as it does not perform any blocking operations.
+ *
+ * @return A pointer to the current malloc function.
+ */
+STUMPLESS_PUBLIC_FUNCTION
+void *(*stumpless_get_malloc(void))(size_t size);
+
+/**
+ * Retrieves the current free function used by the library.
+ *
+ * **Thread Safety: MT-Safe**
+ * This function is thread-safe as it does not modify any global state.
+ * It simply retrieves a pointer to the current memory deallocation function.
+ *
+ * **Async Signal Safety: AS-Safe**
+ * This function is safe to call from signal handlers since it does not
+ * cause any side effects or modify state.
+ *
+ * **Async Cancel Safety: AC-Safe**
+ * This function is safe to call from threads that may be asynchronously
+ * cancelled as it does not perform any blocking operations.
+ *
+ * @return A pointer to the current free function.
+ */
+STUMPLESS_PUBLIC_FUNCTION
+void (*stumpless_get_free(void))(void *ptr);
+
+/**
+ * Retrieves the current realloc function used by the library.
+ *
+ * **Thread Safety: MT-Safe**
+ * This function is thread-safe as it does not modify any global state.
+ * It simply retrieves a pointer to the current memory reallocation function.
+ *
+ * **Async Signal Safety: AS-Safe**
+ * This function is safe to call from signal handlers since it does not
+ * cause any side effects or modify state.
+ *
+ * **Async Cancel Safety: AC-Safe**
+ * This function is safe to call from threads that may be asynchronously
+ * cancelled as it does not perform any blocking operations.
+ *
+ * @return A pointer to the current realloc function.
+ */
+STUMPLESS_PUBLIC_FUNCTION
+void *(*stumpless_get_realloc(void))(void *ptr, size_t size);
+
 #  ifdef __cplusplus
 }                               /* extern "C" */
 #  endif

include/test/helper/memory_counter.hpp

@@ -23,6 +23,7 @@
 #include <cstddef>
 #include <cstdlib>
 #include <stumpless.h>
+#include <stumpless/memory.h>
 
 struct memory_counter {
   size_t malloc_count;
@@ -41,9 +42,9 @@ PREFIX##_memory_counter.alloc_total = 0;                                       \
 PREFIX##_memory_counter.realloc_count = 0;                                     \
 PREFIX##_memory_counter.free_count = 0;                                        \
 PREFIX##_memory_counter.free_total = 0;                                        \
-PREFIX##_memory_counter.previous_malloc = malloc;                              \
-PREFIX##_memory_counter.previous_realloc = realloc;                            \
-PREFIX##_memory_counter.previous_free = free;                                  \
+PREFIX##_memory_counter.previous_malloc = stumpless_get_malloc();              \
+PREFIX##_memory_counter.previous_realloc = stumpless_get_realloc();            \
+PREFIX##_memory_counter.previous_free = stumpless_get_free();                  \
 stumpless_set_malloc( PREFIX##_memory_counter_malloc );                        \
 stumpless_set_realloc( PREFIX##_memory_counter_realloc );                      \
 stumpless_set_free( PREFIX##_memory_counter_free );
@@ -107,4 +108,4 @@ PREFIX##_memory_counter_free( void *mem ) {                                    \
 ASSERT_EQ( PREFIX##_memory_counter.alloc_total,                                \
            PREFIX##_memory_counter.free_total )
 
-#endif /* __STUMPLESS_TEST_HELPER_MEMORY_COUNTER_HPP */
+#endif /* __STUMPLESS_TEST_HELPER_MEMORY_COUNTER_HPP */