diff -r aa465fac4ef6 -r afd87df80b13 test/util_allocator.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/util_allocator.c	Sun Sep 26 14:41:16 2021 +0200
@@ -0,0 +1,126 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "util_allocator.h"
+#include <string.h>
+
+void cx_testing_allocator_add(cx_testing_allocator_s *data, void *ptr) {
+    data->tracked[data->live] = ptr;
+    data->live++;
+}
+
+int cx_testing_allocator_remove(cx_testing_allocator_s *data, void *ptr) {
+    for (int i = 0; i < data->live; i++) {
+        if (data->tracked[i] == ptr) {
+            data->tracked[i] = data->tracked[data->live - 1];
+            data->live--;
+            return 0;
+        }
+    }
+    return 1;
+}
+
+void *cx_malloc_testing(void *d, size_t n) {
+    cx_testing_allocator_s *data = d;
+    void *ptr = malloc(n);
+    data->alloc_total++;
+    if (ptr == NULL) {
+        data->alloc_failed++;
+    } else {
+        cx_testing_allocator_add(data, ptr);
+    }
+    return ptr;
+}
+
+void *cx_realloc_testing(void *d, void *mem, size_t n) {
+    cx_testing_allocator_s *data = d;
+    void *ptr = realloc(mem, n);
+    if (ptr == mem) {
+        return ptr;
+    } else {
+        data->alloc_total++;
+        if (ptr == NULL) {
+            data->alloc_failed++;
+        } else {
+            data->free_total++;
+            if (cx_testing_allocator_remove(data, mem)) {
+                data->free_failed++;
+            }
+            cx_testing_allocator_add(data, ptr);
+        }
+        return ptr;
+    }
+}
+
+void *cx_calloc_testing(void *d, size_t nelem, size_t n) {
+    cx_testing_allocator_s *data = d;
+    void *ptr = calloc(nelem, n);
+    data->alloc_total++;
+    if (ptr == NULL) {
+        data->alloc_failed++;
+    } else {
+        cx_testing_allocator_add(data, ptr);
+    }
+    return ptr;
+}
+
+void cx_free_testing(void *d, void *mem) {
+    cx_testing_allocator_s *data = d;
+    data->free_total++;
+    if (cx_testing_allocator_remove(data, mem)) {
+        data->free_failed++;
+        // do not even attempt to free mem, because it is likely to segfault
+    } else {
+        free(mem);
+    }
+}
+
+cx_allocator_class cx_testing_allocator_class = {
+        cx_malloc_testing,
+        cx_realloc_testing,
+        cx_calloc_testing,
+        cx_free_testing
+};
+
+cx_testing_allocator_s cx_testing_allocator_data;
+
+struct cx_allocator_s cx_testing_allocator = {
+        &cx_testing_allocator_class,
+        &cx_testing_allocator_data
+};
+CxAllocator cxTestingAllocator = &cx_testing_allocator;
+
+void cxTestingAllocatorReset(void) {
+    memset(&cx_testing_allocator_data, 0, sizeof(cx_testing_allocator_s));
+}
+
+int cxTestingAllocatorVerify(void) {
+    return cx_testing_allocator_data.live == 0
+           && cx_testing_allocator_data.alloc_failed == 0 && cx_testing_allocator_data.free_failed == 0
+           && cx_testing_allocator_data.alloc_total == cx_testing_allocator_data.free_total;
+}