Move bufsize_roundup() -> sudo_pow2_roundup() in libsudo_util.

lib/util/roundup.c

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * 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 "config.h"
+
+#include <sys/types.h>
+
+#include "sudo_compat.h"
+#include "sudo_debug.h"
+#include "sudo_util.h"
+
+/*
+ * Round 32-bit unsigned length to the next highest power of two.
+ * Always returns at least 64.
+ * Algorithm from bit twiddling hacks.
+ */
+unsigned int
+sudo_pow2_roundup_v1(unsigned int len)
+{
+    if (len < 64)
+	return 64;
+    len--;
+    len |= len >> 1;
+    len |= len >> 2;
+    len |= len >> 4;
+    len |= len >> 8;
+    len |= len >> 16;
+    len++;
+    return len;
+}