X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=folly%2FTraits.h;h=2b94df1360effe21828adedb51b864e7d2282116;hb=fd915b73606e09a5f46a1bca0a5d3643a1567014;hp=db8bd33a3229d9b5d0abd8141c45a0418894f8c1;hpb=005a6c1f172f4508a9e00b413175750061174724;p=folly.git

diff --git a/folly/Traits.h b/folly/Traits.h
index db8bd33a..2b94df13 100644
--- a/folly/Traits.h
+++ b/folly/Traits.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2014 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,8 +22,20 @@
 #include <memory>
 #include <limits>
 #include <type_traits>
-
+#include <functional>
+
+#include <folly/Portability.h>
+
+// libc++ doesn't provide this header, nor does msvc
+#ifdef FOLLY_HAVE_BITS_CXXCONFIG_H
+// This file appears in two locations: inside fbcode and in the
+// libstdc++ source code (when embedding fbstring as std::string).
+// To aid in this schizophrenic use, two macros are defined in
+// c++config.h:
+//   _LIBSTDCXX_FBSTRING - Set inside libstdc++.  This is useful to
+//      gate use inside fbcode v. libstdc++
 #include <bits/c++config.h>
+#endif
 
 #include <boost/type_traits.hpp>
 #include <boost/mpl/and.hpp>
@@ -223,7 +235,7 @@ template <class T> struct IsZeroInitializable
  * although that is not guaranteed by the standard.
  */
 
-namespace std {
+FOLLY_NAMESPACE_STD_BEGIN
 
 template <class T, class U>
   struct pair;
@@ -247,7 +259,7 @@ template <class K, class V, class C, class A>
 template <class T>
   class shared_ptr;
 
-}
+FOLLY_NAMESPACE_STD_END
 
 namespace boost {
 
@@ -332,7 +344,7 @@ template <typename RHS, RHS rhs, typename LHS>
 bool less_than_impl(
   typename std::enable_if<
     (rhs <= std::numeric_limits<LHS>::max()
-      && rhs >= std::numeric_limits<LHS>::min()),
+      && rhs > std::numeric_limits<LHS>::min()),
     LHS
   >::type const lhs
 ) {
@@ -352,39 +364,39 @@ bool less_than_impl(
 template <typename RHS, RHS rhs, typename LHS>
 bool less_than_impl(
   typename std::enable_if<
-    (rhs < std::numeric_limits<LHS>::min()),
+    (rhs <= std::numeric_limits<LHS>::min()),
     LHS
   >::type const
 ) {
   return false;
 }
 
-template <typename LHS, LHS lhs, typename RHS>
+template <typename RHS, RHS rhs, typename LHS>
 bool greater_than_impl(
   typename std::enable_if<
-    (lhs <= std::numeric_limits<RHS>::max()
-      && lhs >= std::numeric_limits<RHS>::min()),
-    RHS
-  >::type const rhs
+    (rhs <= std::numeric_limits<LHS>::max()
+      && rhs >= std::numeric_limits<LHS>::min()),
+    LHS
+  >::type const lhs
 ) {
-  return lhs < rhs;
+  return lhs > rhs;
 }
 
-template <typename LHS, LHS lhs, typename RHS>
+template <typename RHS, RHS rhs, typename LHS>
 bool greater_than_impl(
   typename std::enable_if<
-    (lhs > std::numeric_limits<RHS>::max()),
-    RHS
+    (rhs > std::numeric_limits<LHS>::max()),
+    LHS
   >::type const
 ) {
   return false;
 }
 
-template <typename LHS, LHS lhs, typename RHS>
+template <typename RHS, RHS rhs, typename LHS>
 bool greater_than_impl(
   typename std::enable_if<
-    (lhs < std::numeric_limits<RHS>::min()),
-    RHS
+    (rhs < std::numeric_limits<LHS>::min()),
+    LHS
   >::type const
 ) {
   return true;
@@ -402,6 +414,16 @@ constexpr bool is_negative(T x) {
 template <typename T>
 constexpr bool is_non_positive(T x) { return !x || folly::is_negative(x); }
 
+// same as `x > 0`
+template <typename T>
+constexpr bool is_positive(T x) { return !is_non_positive(x); }
+
+// same as `x >= 0`
+template <typename T>
+constexpr bool is_non_negative(T x) {
+  return !x || is_positive(x);
+}
+
 template <typename RHS, RHS rhs, typename LHS>
 bool less_than(LHS const lhs) {
   return detail::less_than_impl<
@@ -409,11 +431,11 @@ bool less_than(LHS const lhs) {
   >(lhs);
 }
 
-template <typename LHS, LHS lhs, typename RHS>
-bool greater_than(RHS const rhs) {
+template <typename RHS, RHS rhs, typename LHS>
+bool greater_than(LHS const lhs) {
   return detail::greater_than_impl<
-    LHS, lhs, typename std::remove_reference<RHS>::type
-  >(rhs);
+    RHS, rhs, typename std::remove_reference<LHS>::type
+  >(lhs);
 }
 
 } // namespace folly
@@ -422,8 +444,6 @@ FOLLY_ASSUME_FBVECTOR_COMPATIBLE_3(std::basic_string);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::vector);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::list);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::deque);
-FOLLY_ASSUME_FBVECTOR_COMPATIBLE_4(std::map);
-FOLLY_ASSUME_FBVECTOR_COMPATIBLE_3(std::set);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::unique_ptr);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(std::shared_ptr);
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(std::function);