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+/* Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+/*!
+ * \brief Simple write-once allocation-optimal dynamic array.
+ *
+ * Include it into your .c file
+ *
+ * prefix - identifier prefix, e.g. ptr -> struct ptr_dynarray, ptr_dynarray_add(), ...
+ * ntype - data type to be stored. Let it be a number, pointer or small struct
+ * initial_capacity - how many data items will be allocated on stack and copied with assignment
+ *
+ * prefix_dynarray_add() - add a data item
+ * prefix_dynarray_fix() - call EVERYTIME the array is copied from some already invalid stack
+ * prefix_dynarray_free() - call EVERYTIME you dismiss all copies of the array
+ *
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#pragma once
+
+#define DYNARRAY_VISIBILITY_STATIC static
+#define DYNARRAY_VISIBILITY_PUBLIC
+#define DYNARRAY_VISIBILITY_LIBRARY __public__
+
+#define dynarray_declare(prefix, ntype, visibility, initial_capacity) \
+ typedef struct prefix ## _dynarray { \
+ ssize_t capacity; \
+ ssize_t size; \
+ ntype *(*arr)(struct prefix ## _dynarray *dynarray); \
+ ntype init[initial_capacity]; \
+ ntype *_arr; \
+ } prefix ## _dynarray_t; \
+ \
+ visibility ntype *prefix ## _dynarray_arr(prefix ## _dynarray_t *dynarray); \
+ visibility void prefix ## _dynarray_add(prefix ## _dynarray_t *dynarray, \
+ ntype const *to_add); \
+ visibility void prefix ## _dynarray_free(prefix ## _dynarray_t *dynarray);
+
+#define dynarray_foreach(prefix, ntype, ptr, array) \
+ for (ntype *ptr = prefix ## _dynarray_arr(&(array)); \
+ ptr < prefix ## _dynarray_arr(&(array)) + (array).size; ptr++)
+
+#define dynarray_define(prefix, ntype, visibility) \
+ \
+ static void prefix ## _dynarray_free__(struct prefix ## _dynarray *dynarray) \
+ { \
+ if (dynarray->capacity > sizeof(dynarray->init) / sizeof(*dynarray->init)) { \
+ free(dynarray->_arr); \
+ } \
+ } \
+ \
+ __attribute__((unused)) \
+ visibility ntype *prefix ## _dynarray_arr(struct prefix ## _dynarray *dynarray) \
+ { \
+ assert(dynarray->size <= dynarray->capacity); \
+ return (dynarray->capacity <= sizeof(dynarray->init) / sizeof(*dynarray->init) ? \
+ dynarray->init : dynarray->_arr); \
+ } \
+ \
+ static ntype *prefix ## _dynarray_arr_init__(struct prefix ## _dynarray *dynarray) \
+ { \
+ assert(dynarray->capacity == sizeof(dynarray->init) / sizeof(*dynarray->init)); \
+ return dynarray->init; \
+ } \
+ \
+ static ntype *prefix ## _dynarray_arr_arr__(struct prefix ## _dynarray *dynarray) \
+ { \
+ assert(dynarray->capacity > sizeof(dynarray->init) / sizeof(*dynarray->init)); \
+ return dynarray->_arr; \
+ } \
+ \
+ __attribute__((unused)) \
+ visibility void prefix ## _dynarray_add(struct prefix ## _dynarray *dynarray, \
+ ntype const *to_add) \
+ { \
+ if (dynarray->capacity < 0) { \
+ return; \
+ } \
+ if (dynarray->capacity == 0) { \
+ dynarray->capacity = sizeof(dynarray->init) / sizeof(*dynarray->init); \
+ dynarray->arr = prefix ## _dynarray_arr_init__; \
+ } \
+ if (dynarray->size >= dynarray->capacity) { \
+ ssize_t new_capacity = dynarray->capacity * 2 + 1; \
+ ntype *new_arr = calloc(new_capacity, sizeof(ntype)); \
+ if (new_arr == NULL) { \
+ prefix ## _dynarray_free__(dynarray); \
+ dynarray->capacity = dynarray->size = -1; \
+ return; \
+ } \
+ if (dynarray->capacity > 0) { \
+ memcpy(new_arr, prefix ## _dynarray_arr(dynarray), \
+ dynarray->capacity * sizeof(ntype)); \
+ } \
+ prefix ## _dynarray_free__(dynarray); \
+ dynarray->_arr = new_arr; \
+ dynarray->capacity = new_capacity; \
+ dynarray->arr = prefix ## _dynarray_arr_arr__; \
+ } \
+ prefix ## _dynarray_arr(dynarray)[dynarray->size++] = *to_add; \
+ } \
+ \
+ __attribute__((unused)) \
+ visibility void prefix ## _dynarray_free(struct prefix ## _dynarray *dynarray) \
+ { \
+ prefix ## _dynarray_free__(dynarray); \
+ memset(dynarray, 0, sizeof(*dynarray)); \
+ }