1 files changed, 81 insertions, 0 deletions
diff --git a/lib/util/roundup.c b/lib/util/roundup.c
new file mode 100644
index 0000000..73cf4af
--- /dev/null
+++ b/lib/util/roundup.c
@@ -0,0 +1,81 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * 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.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.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.
+ */
+unsigned int
+sudo_pow2_roundup_v1(unsigned int len)
+{
+    if (len < 64)
+	return 64;
+
+#ifdef HAVE___BUILTIN_CLZ
+    return 1U << (32 - __builtin_clz(len - 1));
+#else
+    len--;
+    len |= len >> 1;
+    len |= len >> 2;
+    len |= len >> 4;
+    len |= len >> 8;
+    len |= len >> 16;
+    len++;
+    return len;
+#endif
+}
+
+/*
+ * Round a size_t length to the next highest power of two.
+ * Always returns at least 64.
+ */
+size_t
+sudo_pow2_roundup_v2(size_t len)
+{
+    if (len < 64)
+	return 64;
+
+#if defined(__LP64__) && defined(HAVE___BUILTIN_CLZL)
+    return 1UL << (64 - __builtin_clzl(len - 1));
+#elif !defined(__LP64__) && defined(HAVE___BUILTIN_CLZ)
+    return 1U << (32 - __builtin_clz(len - 1));
+#else
+    len--;
+    len |= len >> 1;
+    len |= len >> 2;
+    len |= len >> 4;
+    len |= len >> 8;
+    len |= len >> 16;
+# ifdef __LP64__
+    len |= len >> 32;
+# endif
+    len++;
+    return len;
+#endif
+}