initial code repo

[stor4nfv.git] / src / ceph / src / include / intarith.h

diff --git a/src/ceph/src/include/intarith.h b/src/ceph/src/include/intarith.h
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+++ b/src/ceph/src/include/intarith.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software 
+ * Foundation.  See file COPYING.
+ * 
+ */
+
+#ifndef CEPH_INTARITH_H
+#define CEPH_INTARITH_H
+
+#ifndef MIN
+#define MIN(a,b) ((a) < (b) ? (a):(b))
+#endif
+
+#ifndef MAX
+#define MAX(a,b) ((a) > (b) ? (a):(b))
+#endif
+
+#ifndef DIV_ROUND_UP
+#define DIV_ROUND_UP(n, d)  (((n) + (d) - 1) / (d))
+#endif
+
+#ifndef ROUND_UP_TO
+#define ROUND_UP_TO(n, d) ((n)%(d) ? ((n)+(d)-(n)%(d)) : (n))
+#endif
+
+#ifndef SHIFT_ROUND_UP
+#define SHIFT_ROUND_UP(x,y) (((x)+(1<<(y))-1) >> (y))
+#endif
+
+/*
+ * Macro to determine if value is a power of 2
+ */
+#define ISP2(x)                (((x) & ((x) - 1)) == 0)
+
+/*
+ * Macros for various sorts of alignment and rounding.  The "align" must
+ * be a power of 2.  Often times it is a block, sector, or page.
+ */
+
+/*
+ * return x rounded down to an align boundary
+ * eg, P2ALIGN(1200, 1024) == 1024 (1*align)
+ * eg, P2ALIGN(1024, 1024) == 1024 (1*align)
+ * eg, P2ALIGN(0x1234, 0x100) == 0x1200 (0x12*align)
+ * eg, P2ALIGN(0x5600, 0x100) == 0x5600 (0x56*align)
+ */
+#define P2ALIGN(x, align)              ((x) & -(align))
+
+/*
+ * return x % (mod) align
+ * eg, P2PHASE(0x1234, 0x100) == 0x34 (x-0x12*align)
+ * eg, P2PHASE(0x5600, 0x100) == 0x00 (x-0x56*align)
+ */
+#define P2PHASE(x, align)              ((x) & ((align) - 1))
+
+/*
+ * return how much space is left in this block (but if it's perfectly
+ * aligned, return 0).
+ * eg, P2NPHASE(0x1234, 0x100) == 0xcc (0x13*align-x)
+ * eg, P2NPHASE(0x5600, 0x100) == 0x00 (0x56*align-x)
+ */
+#define P2NPHASE(x, align)             (-(x) & ((align) - 1))
+
+/*
+ * return x rounded up to an align boundary
+ * eg, P2ROUNDUP(0x1234, 0x100) == 0x1300 (0x13*align)
+ * eg, P2ROUNDUP(0x5600, 0x100) == 0x5600 (0x56*align)
+ */
+#define P2ROUNDUP(x, align)            (-(-(x) & -(align)))
+
+// count trailing zeros.
+// NOTE: the builtin is nondeterministic on 0 input
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) <= sizeof(unsigned)),
+  unsigned>::type ctz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_ctz(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned int) &&
+   sizeof(T) <= sizeof(unsigned long)),
+  unsigned>::type ctz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_ctzl(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned long) &&
+   sizeof(T) <= sizeof(unsigned long long)),
+  unsigned>::type ctz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_ctzll(v);
+}
+
+// count leading zeros
+// NOTE: the builtin is nondeterministic on 0 input
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) <= sizeof(unsigned)),
+  unsigned>::type clz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_clz(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned int) &&
+   sizeof(T) <= sizeof(unsigned long)),
+  unsigned>::type clz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_clzl(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned long) &&
+   sizeof(T) <= sizeof(unsigned long long)),
+  unsigned>::type clz(T v) {
+  if (v == 0)
+    return sizeof(v) * 8;
+  return __builtin_clzll(v);
+}
+
+// count bits (set + any 0's that follow)
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) <= sizeof(unsigned)),
+  unsigned>::type cbits(T v) {
+  if (v == 0)
+    return 0;
+  return (sizeof(v) * 8) - __builtin_clz(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned int) &&
+   sizeof(T) <= sizeof(unsigned long)),
+  unsigned>::type cbits(T v) {
+  if (v == 0)
+    return 0;
+  return (sizeof(v) * 8) - __builtin_clzl(v);
+}
+
+template<class T>
+  inline typename std::enable_if<
+  (std::is_integral<T>::value &&
+   sizeof(T) > sizeof(unsigned long) &&
+   sizeof(T) <= sizeof(unsigned long long)),
+  unsigned>::type cbits(T v) {
+  if (v == 0)
+    return 0;
+  return (sizeof(v) * 8) - __builtin_clzll(v);
+}
+
+#endif