core: Add pointer box impl

Signed-off-by: Ian Moffett <ian@mirocom.org>

core/ptrbox.c

@@ -0,0 +1,86 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include "rifle/ptrbox.h"
+
+int
+ptrbox_init(struct ptrbox *res)
+{
+    if (res == NULL) {
+        errno = -EINVAL;
+        return -1;
+    }
+
+    TAILQ_INIT(&res->entries);
+    res->entry_count = 0;
+    return 0;
+}
+
+void *
+ptrbox_alloc(struct ptrbox *ptrbox, size_t sz)
+{
+    struct ptrbox_entry *entry;
+
+    if (ptrbox == NULL || sz == 0) {
+        return NULL;
+    }
+
+    if ((entry = malloc(sizeof(*entry))) == NULL) {
+        return NULL;
+    }
+
+    if ((entry->data = malloc(sz)) == NULL) {
+        free(entry);
+        return NULL;
+    }
+
+    TAILQ_INSERT_TAIL(&ptrbox->entries, entry, link);
+    ++ptrbox->entry_count;
+    return entry->data;
+}
+
+void *
+ptrbox_strdup(struct ptrbox *ptrbox, const char *s)
+{
+    struct ptrbox_entry *entry;
+
+    if (ptrbox == NULL || s == 0) {
+        return NULL;
+    }
+
+    if ((entry = malloc(sizeof(*entry))) == NULL) {
+        return NULL;
+    }
+
+    if ((entry->data = strdup(s)) == NULL) {
+        free(entry);
+        return NULL;
+    }
+
+    TAILQ_INSERT_TAIL(&ptrbox->entries, entry, link);
+    ++ptrbox->entry_count;
+    return entry->data;
+}
+
+void
+ptrbox_destroy(struct ptrbox *ptrbox)
+{
+    struct ptrbox_entry *entry;
+
+    if (ptrbox == NULL) {
+        return;
+    }
+
+    if ((entry = TAILQ_FIRST(&ptrbox->entries)) == NULL) {
+        return;
+    }
+
+    do {
+        TAILQ_REMOVE(&ptrbox->entries, entry, link);
+        free(entry->data);
+        free(entry);
+        entry = TAILQ_FIRST(&ptrbox->entries);
+    } while (entry != NULL);
+}

inc/rifle/ptrbox.h

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2026, Ian Moffett.
+ * Provided under the BSD-3 clause.
+ */
+
+#ifndef RIFLE_PTRBOX_H
+#define RIFLE_PTRBOX_H
+
+#include <sys/queue.h>
+#include <stdint.h>
+#include <stddef.h>
+
+/*
+ * Represents a pointer box entry which stores a reference
+ * to allocated memory
+ *
+ * @data: Allocated memory
+ * @link: Queue link
+ */
+struct ptrbox_entry {
+    void *data;
+    TAILQ_ENTRY(ptrbox_entry) link;
+};
+
+/*
+ * A pointer box stores one or more references to allocated memory
+ * so that it can be cleaned up in one sweep when usage is complete.
+ *
+ * @entries: Pointer box entries
+ * @entry_count: Number of entries in pointer box
+ */
+struct ptrbox {
+    TAILQ_HEAD(, ptrbox_entry) entries;
+    size_t entry_count;
+};
+
+/*
+ * Allocate memory and save it in a pointer box
+ *
+ * @ptrbox: Pointer box to save reference in
+ * @sz: Allocation size
+ *
+ * Returns the base of the allocated memory on success
+ */
+void *ptrbox_alloc(struct ptrbox *ptrbox, size_t sz);
+
+/*
+ * Perform a strdup() operation and save the reference in
+ * a pointer box
+ *
+ * @ptrbox: Ptrbox to save reference within
+ * @s: String to dup
+ *
+ * Returns dupped string on success
+ */
+void *ptrbox_strdup(struct ptrbox *ptrbox, const char *s);
+
+/*
+ * Destroy a pointer box
+ *
+ * @ptrbox: Pointer box to destory
+ */
+void ptrbox_destroy(struct ptrbox *ptrbox);
+
+/*
+ * Initialize a pointer box
+ *
+ * @res: Pointer box to initialize
+ *
+ * Returns zero on success
+ */
+int ptrbox_init(struct ptrbox *res);
+
+#endif  /* !RIFLE_PTRBOX_H */