--- /dev/null
+/*
+libanim - hierarchical keyframe animation library
+Copyright (C) 2012-2014 John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published
+by the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "dynarr.h"
+
+/* The array descriptor keeps auxilliary information needed to manipulate
+ * the dynamic array. It's allocated adjacent to the array buffer.
+ */
+struct arrdesc {
+ int nelem, szelem;
+ int max_elem;
+ int bufsz; /* not including the descriptor */
+};
+
+#define DESC(x) ((struct arrdesc*)((char*)(x) - sizeof(struct arrdesc)))
+
+void *anm_dynarr_alloc(int elem, int szelem)
+{
+ struct arrdesc *desc;
+
+ if(!(desc = malloc(elem * szelem + sizeof *desc))) {
+ return 0;
+ }
+ desc->nelem = desc->max_elem = elem;
+ desc->szelem = szelem;
+ desc->bufsz = elem * szelem;
+ return (char*)desc + sizeof *desc;
+}
+
+void anm_dynarr_free(void *da)
+{
+ if(da) {
+ free(DESC(da));
+ }
+}
+
+void *anm_dynarr_resize(void *da, int elem)
+{
+ int newsz;
+ void *tmp;
+ struct arrdesc *desc;
+
+ if(!da) return 0;
+ desc = DESC(da);
+
+ newsz = desc->szelem * elem;
+
+ if(!(tmp = realloc(desc, newsz + sizeof *desc))) {
+ return 0;
+ }
+ desc = tmp;
+
+ desc->nelem = desc->max_elem = elem;
+ desc->bufsz = newsz;
+ return (char*)desc + sizeof *desc;
+}
+
+int anm_dynarr_empty(void *da)
+{
+ return DESC(da)->nelem ? 0 : 1;
+}
+
+int anm_dynarr_size(void *da)
+{
+ return DESC(da)->nelem;
+}
+
+
+/* stack semantics */
+void *anm_dynarr_push(void *da, void *item)
+{
+ struct arrdesc *desc;
+ int nelem;
+
+ desc = DESC(da);
+ nelem = desc->nelem;
+
+ if(nelem >= desc->max_elem) {
+ /* need to resize */
+ struct arrdesc *tmp;
+ int newsz = desc->max_elem ? desc->max_elem * 2 : 1;
+
+ if(!(tmp = anm_dynarr_resize(da, newsz))) {
+ fprintf(stderr, "failed to resize\n");
+ return da;
+ }
+ da = tmp;
+ desc = DESC(da);
+ desc->nelem = nelem;
+ }
+
+ memcpy((char*)da + desc->nelem++ * desc->szelem, item, desc->szelem);
+ return da;
+}
+
+void *anm_dynarr_pop(void *da)
+{
+ struct arrdesc *desc;
+ int nelem;
+
+ desc = DESC(da);
+ nelem = desc->nelem;
+
+ if(!nelem) return da;
+
+ if(nelem <= desc->max_elem / 3) {
+ /* reclaim space */
+ struct arrdesc *tmp;
+ int newsz = desc->max_elem / 2;
+
+ if(!(tmp = anm_dynarr_resize(da, newsz))) {
+ fprintf(stderr, "failed to resize\n");
+ return da;
+ }
+ da = tmp;
+ desc = DESC(da);
+ desc->nelem = nelem;
+ }
+ desc->nelem--;
+
+ return da;
+}