ircd::math: Start supplemental library; move log2 constexprs from util.

include/ircd/ircd.h

@@ -76,6 +76,7 @@
 #include "b58.h"
 #include "iov.h"
 #include "time.h"
+#include "math/math.h"
 #include "grammar.h"
 #include "parse.h"
 #include "fmt.h"

include/ircd/math/log2.h

@@ -0,0 +1,57 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_MATH_LOG2_H
+
+namespace ircd::math
+{
+	template<class Z> constexpr bool is_pow2(const Z);
+	template<class Z> constexpr Z next_pow2(const Z);
+	template<class Z> constexpr Z log2(const Z);
+	template<class Z> constexpr Z sqr(const Z);
+}
+
+template<class Z>
+inline constexpr Z
+ircd::math::sqr(const Z n)
+{
+	return pow(n, 2);
+}
+
+template<class Z>
+inline constexpr Z
+ircd::math::log2(const Z n)
+{
+	return n > Z{1}?
+		Z{1} + log2(n >> 1):
+		0;
+}
+
+template<class Z>
+inline constexpr Z
+ircd::math::next_pow2(Z v)
+{
+	--v;
+	v |= v >> 1;
+	v |= v >> 2;
+	v |= v >> 4;
+	v |= v >> 8;
+	v |= v >> 16;
+	v |= v >> 32;
+	return ++v;
+}
+
+template<class Z>
+inline constexpr bool
+ircd::math::is_pow2(const Z v)
+{
+	return v && !(v & (v - Z{1}));
+}

include/ircd/math/math.h

@@ -0,0 +1,14 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_MATH_MATH_H
+
+#include "log2.h"

include/ircd/util/util.h

@@ -241,25 +241,6 @@ until(it_a a,
 	return true;
 }
 
-constexpr bool
-is_powerof2(const long long v)
-{
-	return v && !(v & (v - 1LL));
-}
-
-constexpr uint64_t
-next_powerof2(uint64_t v)
-{
-	--v;
-	v |= v >> 1;
-	v |= v >> 2;
-	v |= v >> 4;
-	v |= v >> 8;
-	v |= v >> 16;
-	v |= v >> 32;
-	return ++v;
-}
-
 template<class T>
 T
 minmax(T ret,

ircd/db_allocator.cc

@@ -462,7 +462,7 @@ ircd::db::database::allocator::allocator(database *const &d,
 	#endif
 }
 {
-	assert(is_powerof2(alignment));
+	assert(math::is_pow2(alignment));
 }
 
 ircd::db::database::allocator::~allocator()

modules/client/keys/claim.cc

@@ -285,7 +285,7 @@ try
 		+ 128                         // algorithm
 	};
 
-	static_assert(is_powerof2(buffer_unit_size));
+	static_assert(math::is_pow2(buffer_unit_size));
 	const size_t buffer_size
 	{
 		8_KiB + // headers