core: Add support for pointer boxes

Pointer boxes are a way to manage memory and have all references
released after operation, this way they do not need to be manually
managed.

Signed-off-by: Chloe M. <chloe@aptel.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/core/ptrbox.c b/core/ptrbox.c
new file mode 100644
index 0000000..f6e2254
--- /dev/null
+++ b/core/ptrbox.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2026, Apollo Telephone Laboratories.
+ * Provided under the BSD-3 clause.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "defconf/ptrbox.h"
+
+static inline void
+ptrbox_insert(struct ptrbox *ptrbox, struct ptrbox_entry *entry)
+{
+    if (ptrbox == NULL || entry == NULL) {
+        return;
+    }
+
+    TAILQ_INSERT_TAIL(&ptrbox->entries, entry, link);
+    ++ptrbox->entry_count;
+}
+
+/*
+ * Allocate a new pointer box entry
+ *
+ * @data:  Data to be associated with pointer box entry
+ */
+static struct ptrbox_entry *
+ptrbox_alloc_entry(void *data)
+{
+    struct ptrbox_entry *entry;
+
+    if (data == NULL) {
+        return NULL;
+    }
+
+    entry = malloc(sizeof(*entry));
+    if (entry == NULL) {
+        return NULL;
+    }
+
+    entry->data = data;
+    return entry;
+}
+
+char *
+ptrbox_strdup(struct ptrbox *ptrbox, const char *s)
+{
+    struct ptrbox_entry *entry;
+    char *dup;
+
+    if (ptrbox == NULL || s == NULL) {
+        return NULL;
+    }
+
+    if ((dup = strdup(s)) == NULL) {
+        return NULL;
+    }
+
+    if ((entry = ptrbox_alloc_entry(dup)) == NULL) {
+        free(dup);
+        return NULL;
+    }
+
+    ptrbox_insert(ptrbox, entry);
+    return dup;
+}
+
+int
+ptrbox_init(struct ptrbox *ptrbox)
+{
+    if (ptrbox == NULL) {
+        return -1;
+    }
+
+    TAILQ_INIT(&ptrbox->entries);
+    ptrbox->entry_count = 0;
+    return 0;
+}
+
+void
+ptrbox_destroy(struct ptrbox *ptrbox)
+{
+    struct ptrbox_entry *entry, *tmp;
+
+    if (ptrbox == NULL) {
+        return;
+    }
+
+    entry = TAILQ_FIRST(&ptrbox->entries);
+    while (entry != NULL) {
+        if (entry->data != NULL) {
+            free(entry->data);
+        }
+
+        tmp = entry;
+        entry = TAILQ_NEXT(entry, link);
+        free(tmp);
+    }
+}