From 1c47ffcce8e7235c06792e92aa99ac97d7f3fb8e Mon Sep 17 00:00:00 2001
From: "Anthony J. Bentley" <anthony@cathet.us>
Date: Sat, 14 Feb 2015 00:14:39 -0700
Subject: [PATCH] Import reallocarray() for later use.

---
 include/extern/reallocarray.h | 10 +++++++++
 src/extern/reallocarray.c     | 38 +++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 include/extern/reallocarray.h
 create mode 100644 src/extern/reallocarray.c

diff --git a/include/extern/reallocarray.h b/include/extern/reallocarray.h
new file mode 100644
index 00000000..e8ab5709
--- /dev/null
+++ b/include/extern/reallocarray.h
@@ -0,0 +1,10 @@
+#ifndef EXTERN_REALLOCARRAY_H
+#define EXTERN_REALLOCARRAY_H
+
+#include <stdlib.h>
+
+#ifndef REALLOCARRAY_IN_LIBC
+#define reallocarray rgbds_reallocarray
+#endif
+
+#endif
diff --git a/src/extern/reallocarray.c b/src/extern/reallocarray.c
new file mode 100644
index 00000000..e6f4fa52
--- /dev/null
+++ b/src/extern/reallocarray.c
@@ -0,0 +1,38 @@
+/*	$OpenBSD: reallocarray.c,v 1.2 2014/12/08 03:45:00 bcook Exp $	*/
+/*
+ * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * 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 <sys/types.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/*
+ * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
+ * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
+ */
+#define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
+
+void *
+rgbds_reallocarray(void *optr, size_t nmemb, size_t size)
+{
+	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
+	    nmemb > 0 && SIZE_MAX / nmemb < size) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	return realloc(optr, size * nmemb);
+}