summaryrefslogtreecommitdiffstats
path: root/src/darray.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/darray.c')
-rw-r--r--src/darray.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/src/darray.c b/src/darray.c
new file mode 100644
index 0000000..6585d30
--- /dev/null
+++ b/src/darray.c
@@ -0,0 +1,103 @@
+/****************************************************************************
+ * bfs *
+ * Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com> *
+ * *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted. *
+ * *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
+ ****************************************************************************/
+
+#include "darray.h"
+#include <stdlib.h>
+#include <string.h>
+
+/**
+ * The darray header.
+ */
+struct darray {
+ /** The current capacity of the array, as a count of elements. */
+ size_t capacity;
+ /** The current length of the array. */
+ size_t length;
+
+ // The array elements are stored after this header in memory. Not using
+ // a flexible array member to avoid worrying about strict aliasing. We
+ // assume that 2*sizeof(size_t) keeps any memory allocation suitably
+ // aligned for the element type.
+};
+
+/** Get the header for a darray. */
+static struct darray *darray_header(const void *da) {
+ return (struct darray *)da - 1;
+}
+
+/** Get the array from a darray header. */
+static char *darray_data(struct darray *header) {
+ return (char *)(header + 1);
+}
+
+size_t darray_length(const void *da) {
+ if (da) {
+ return darray_header(da)->length;
+ } else {
+ return 0;
+ }
+}
+
+void *darray_push(void *da, const void *item, size_t size) {
+ struct darray *header;
+ if (da) {
+ header = darray_header(da);
+ } else {
+ header = malloc(sizeof(*header) + size);
+ if (!header) {
+ return NULL;
+ }
+ header->capacity = 1;
+ header->length = 0;
+ }
+
+ size_t capacity = header->capacity;
+ size_t i = header->length++;
+ if (i >= capacity) {
+ capacity *= 2;
+ header = realloc(header, sizeof(*header) + capacity*size);
+ if (!header) {
+ // This failure will be detected by darray_check()
+ return da;
+ }
+ header->capacity = capacity;
+ }
+
+ char *data = darray_data(header);
+ memcpy(data + i*size, item, size);
+ return data;
+}
+
+int darray_check(void *da) {
+ if (!da) {
+ return -1;
+ }
+
+ struct darray *header = darray_header(da);
+ if (header->length <= header->capacity) {
+ return 0;
+ } else {
+ // realloc() failed in darray_push(), so reset the length and report the failure
+ header->length = header->capacity;
+ return -1;
+ }
+}
+
+void darray_free(void *da) {
+ if (da) {
+ free(darray_header(da));
+ }
+}