1 files changed, 54 insertions, 0 deletions
diff --git a/xpcom/base/nsAlgorithm.h b/xpcom/base/nsAlgorithm.h
new file mode 100644
index 0000000000..1c4bb0e9dc
--- /dev/null
+++ b/xpcom/base/nsAlgorithm.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAlgorithm_h___
+#define nsAlgorithm_h___
+
+#include <cstdint>
+#include "mozilla/Assertions.h"
+
+template <class T>
+inline T NS_ROUNDUP(const T& aA, const T& aB) {
+  return ((aA + (aB - 1)) / aB) * aB;
+}
+
+// We use these instead of std::min/max because we can't include the algorithm
+// header in all of XPCOM because the stl wrappers will error out when included
+// in parts of XPCOM. These functions should never be used outside of XPCOM.
+template <class T>
+inline const T& XPCOM_MIN(const T& aA, const T& aB) {
+  return aB < aA ? aB : aA;
+}
+
+// Must return b when a == b in case a is -0
+template <class T>
+inline const T& XPCOM_MAX(const T& aA, const T& aB) {
+  return aA > aB ? aA : aB;
+}
+
+namespace mozilla {
+
+template <class T>
+inline const T& clamped(const T& aA, const T& aMin, const T& aMax) {
+  MOZ_ASSERT(aMax >= aMin,
+             "clamped(): aMax must be greater than or equal to aMin");
+  return XPCOM_MIN(XPCOM_MAX(aA, aMin), aMax);
+}
+
+}  // namespace mozilla
+
+template <class InputIterator, class T>
+inline uint32_t NS_COUNT(InputIterator& aFirst, const InputIterator& aLast,
+                         const T& aValue) {
+  uint32_t result = 0;
+  for (; aFirst != aLast; ++aFirst)
+    if (*aFirst == aValue) {
+      ++result;
+    }
+  return result;
+}
+
+#endif  // !defined(nsAlgorithm_h___)