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Diffstat (limited to 'contrib/dynarray.h')
| -rw-r--r-- | contrib/dynarray.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/contrib/dynarray.h b/contrib/dynarray.h new file mode 100644 index 0000000..7cbb686 --- /dev/null +++ b/contrib/dynarray.h @@ -0,0 +1,112 @@ +/* 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)); \ + } |