diff -r b53e0e003d7e -r ed710122af44 tests/util_allocator.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/util_allocator.c	Wed Dec 27 16:04:38 2023 +0100
@@ -0,0 +1,253 @@
+/*
+ * 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 "cx/test.h"
+
+static void cx_testing_allocator_track(CxTestingAllocator *alloc, void *ptr) {
+    for (size_t i = 0; i < alloc->tracked_count; i++) {
+        if (alloc->tracked[i] == ptr) return; // is already tracked
+    }
+
+    if (alloc->tracked_count == alloc->tracked_capacity) {
+        size_t newcapa = alloc->tracked_capacity + 64;
+        void *newarr = realloc(alloc->tracked, newcapa * sizeof(void *));
+        if (newarr == NULL) abort();
+        alloc->tracked = newarr;
+        alloc->tracked_capacity = newcapa;
+    }
+
+    alloc->tracked[alloc->tracked_count] = ptr;
+    alloc->tracked_count++;
+}
+
+static bool cx_testing_allocator_untrack(CxTestingAllocator *alloc, void *ptr) {
+    for (size_t i = 0; i < alloc->tracked_count; i++) {
+        if (alloc->tracked[i] == ptr) {
+            size_t last = alloc->tracked_count - 1;
+            if (i < last) {
+                alloc->tracked[i] = alloc->tracked[last];
+            }
+            alloc->tracked_count--;
+            return true;
+        }
+    }
+    return false;
+}
+
+static void *cx_malloc_testing(void *d, size_t n) {
+    CxTestingAllocator *data = d;
+    void *ptr = malloc(n);
+    data->alloc_total++;
+    if (ptr == NULL) {
+        data->alloc_failed++;
+    } else {
+        cx_testing_allocator_track(data, ptr);
+    }
+    return ptr;
+}
+
+static void *cx_realloc_testing(void *d, void *mem, size_t n) {
+    CxTestingAllocator *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_untrack(data, mem)) {
+                data->free_failed++;
+            }
+            cx_testing_allocator_track(data, ptr);
+        }
+        return ptr;
+    }
+}
+
+static void *cx_calloc_testing(void *d, size_t nelem, size_t n) {
+    CxTestingAllocator *data = d;
+    void *ptr = calloc(nelem, n);
+    data->alloc_total++;
+    if (ptr == NULL) {
+        data->alloc_failed++;
+    } else {
+        cx_testing_allocator_track(data, ptr);
+    }
+    return ptr;
+}
+
+static void cx_free_testing(void *d, void *mem) {
+    CxTestingAllocator *data = d;
+    data->free_total++;
+    if (cx_testing_allocator_untrack(data, mem)) {
+        free(mem);
+    } else {
+        data->free_failed++;
+        // do not even attempt to free mem, because it is likely to segfault
+    }
+}
+
+cx_allocator_class cx_testing_allocator_class = {
+        cx_malloc_testing,
+        cx_realloc_testing,
+        cx_calloc_testing,
+        cx_free_testing
+};
+
+
+void cx_testing_allocator_init(CxTestingAllocator *alloc) {
+    alloc->base.cl = &cx_testing_allocator_class;
+    alloc->base.data = alloc;
+    alloc->alloc_failed = 0;
+    alloc->alloc_total = 0;
+    alloc->free_failed = 0;
+    alloc->free_total = 0;
+    size_t initial_capa = 16;
+    alloc->tracked_capacity = initial_capa;
+    alloc->tracked_count = 0;
+    alloc->tracked = calloc(sizeof(void *), initial_capa);
+}
+
+void cx_testing_allocator_destroy(CxTestingAllocator *alloc) {
+    free(alloc->tracked);
+}
+
+bool cx_testing_allocator_used(CxTestingAllocator const *alloc) {
+    return alloc->alloc_total > 0;
+}
+
+bool cx_testing_allocator_verify(CxTestingAllocator const *alloc) {
+    return alloc->tracked_count == 0 && alloc->alloc_failed == 0 && alloc->free_failed == 0
+           && alloc->alloc_total == alloc->free_total;
+}
+
+// SELF-TEST
+
+CX_TEST(test_util_allocator_expect_free) {
+    CxTestingAllocator talloc;
+    cx_testing_allocator_init(&talloc);
+    CxAllocator *alloc = &talloc.base;
+    CX_TEST_DO {
+        CX_TEST_ASSERTM(cx_testing_allocator_verify(&talloc),
+                        "Fresh testing allocator fails to verify.");
+        CX_TEST_ASSERTM(!cx_testing_allocator_used(&talloc),
+                        "Fresh testing allocator already used.");
+        void *ptr = cxMalloc(alloc, 16);
+        CX_TEST_ASSERTM(!cx_testing_allocator_verify(&talloc),
+                        "Testing allocator verifies with unfreed memory.");
+        CX_TEST_ASSERT(cx_testing_allocator_used(&talloc));
+        CX_TEST_ASSERT(ptr != NULL);
+
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERTM(cx_testing_allocator_verify(&talloc),
+                        "Testing allocator fails to verify after everything freed.");
+    }
+    cx_testing_allocator_destroy(&talloc);
+}
+
+CX_TEST(test_util_allocator_detect_double_free) {
+    CxTestingAllocator talloc;
+    cx_testing_allocator_init(&talloc);
+    CxAllocator *alloc = &talloc.base;
+    CX_TEST_DO {
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+        void *ptr = cxMalloc(alloc, 16);
+        CX_TEST_ASSERT(ptr != NULL);
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERTM(!cx_testing_allocator_verify(&talloc),
+                        "Testing allocator does not detect double-free.");
+    }
+    cx_testing_allocator_destroy(&talloc);
+}
+
+CX_TEST(test_util_allocator_free_untracked) {
+    CxTestingAllocator talloc;
+    cx_testing_allocator_init(&talloc);
+    CxAllocator *alloc = &talloc.base;
+    void *ptr = malloc(16);
+    CX_TEST_DO {
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERTM(!cx_testing_allocator_verify(&talloc),
+                        "Testing allocator does not detect free of untracked memory.");
+    }
+    free(ptr);
+    cx_testing_allocator_destroy(&talloc);
+}
+
+CX_TEST(test_util_allocator_full_lifecycle_with_realloc) {
+    CxTestingAllocator talloc;
+    cx_testing_allocator_init(&talloc);
+    CxAllocator *alloc = &talloc.base;
+    CX_TEST_DO {
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+        void *ptr = cxMalloc(alloc, 16);
+        CX_TEST_ASSERT(!cx_testing_allocator_verify(&talloc));
+        CX_TEST_ASSERT(ptr != NULL);
+        CX_TEST_ASSERT(talloc.tracked_count == 1);
+        ptr = cxRealloc(alloc, ptr, 256);
+        CX_TEST_ASSERT(!cx_testing_allocator_verify(&talloc));
+        CX_TEST_ASSERT(ptr != NULL);
+        CX_TEST_ASSERT(talloc.tracked_count == 1);
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+    }
+    cx_testing_allocator_destroy(&talloc);
+}
+
+CX_TEST(test_util_allocator_calloc_initializes) {
+    CxTestingAllocator talloc;
+    cx_testing_allocator_init(&talloc);
+    CxAllocator *alloc = &talloc.base;
+    CX_TEST_DO {
+        const char zeros[16] = {0};
+        void *ptr = cxCalloc(alloc, 16, 1);
+        CX_TEST_ASSERT(memcmp(ptr, zeros, 16) == 0);
+        cxFree(alloc, ptr);
+        CX_TEST_ASSERT(cx_testing_allocator_verify(&talloc));
+    }
+    cx_testing_allocator_destroy(&talloc);
+}
+
+CxTestSuite *cx_test_suite_testing_allocator(void) {
+    CxTestSuite *suite = cx_test_suite_new("testing allocator self-test");
+
+    cx_test_register(suite, test_util_allocator_expect_free);
+    cx_test_register(suite, test_util_allocator_detect_double_free);
+    cx_test_register(suite, test_util_allocator_free_untracked);
+    cx_test_register(suite, test_util_allocator_full_lifecycle_with_realloc);
+    cx_test_register(suite, test_util_allocator_calloc_initializes);
+
+    return suite;
+}
+