From f381e80fa50bf5f3e94e90ded2fc25c98ff45817 Mon Sep 17 00:00:00 2001
From: Xidorn Quan <quanxunzhen@gmail.com>
Date: Wed, 4 Feb 2015 19:07:32 +1100
Subject: [PATCH] Bug 1126701 - Add IntegerRange for iterating integers.
r=waldo
--HG--
extra : source : 2977cf3c5b545826a4ec0cdf245e804574cf7ff9
---
mfbt/IntegerRange.h | 202 ++++++++++++++++++++++++++++++++++++++++++++
mfbt/moz.build | 1 +
2 files changed, 203 insertions(+)
create mode 100644 mfbt/IntegerRange.h
diff --git a/mfbt/IntegerRange.h b/mfbt/IntegerRange.h
new file mode 100644
index 0000000000000..44d1d6c80c85c
--- /dev/null
+++ b/mfbt/IntegerRange.h
@@ -0,0 +1,202 @@
+/* -*- 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/. */
+
+/* Iterator over ranges of integers */
+
+#ifndef mozilla_IntegerRange_h
+#define mozilla_IntegerRange_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/TypeTraits.h"
+#include "mozilla/ReverseIterator.h"
+
+namespace mozilla {
+
+namespace detail {
+
+template<typename IntTypeT>
+class IntegerIterator
+{
+public:
+ typedef const IntTypeT ValueType;
+ typedef typename MakeSigned<IntTypeT>::Type DifferenceType;
+
+ template<typename IntType>
+ explicit IntegerIterator(IntType aCurrent)
+ : mCurrent(aCurrent) { }
+
+ template<typename IntType>
+ IntegerIterator(const IntegerIterator<IntType>& aOther)
+ : mCurrent(aOther.mCurrent) { }
+
+ // Since operator* is required to return a reference, we return
+ // the reference of our member here.
+ const IntTypeT& operator*() const { return mCurrent; }
+
+ /* Increments and descrements operators */
+
+ IntegerIterator& operator++() { ++mCurrent; return *this; }
+ IntegerIterator& operator--() { --mCurrent; return *this; }
+ IntegerIterator operator++(int) { auto ret = *this; ++mCurrent; return ret; }
+ IntegerIterator operator--(int) { auto ret = *this; --mCurrent; return ret; }
+
+ IntegerIterator operator+(DifferenceType aN) const
+ {
+ return IntegerIterator(mCurrent + aN);
+ }
+ IntegerIterator operator-(DifferenceType aN) const
+ {
+ return IntegerIterator(mCurrent - aN);
+ }
+ IntegerIterator& operator+=(DifferenceType aN)
+ {
+ mCurrent += aN;
+ return *this;
+ }
+ IntegerIterator& operator-=(DifferenceType aN)
+ {
+ mCurrent -= aN;
+ return *this;
+ }
+
+ /* Comparison operators */
+
+ template<typename IntType1, typename IntType2>
+ friend bool operator==(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+ template<typename IntType1, typename IntType2>
+ friend bool operator!=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+ template<typename IntType1, typename IntType2>
+ friend bool operator<(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+ template<typename IntType1, typename IntType2>
+ friend bool operator<=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+ template<typename IntType1, typename IntType2>
+ friend bool operator>(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+ template<typename IntType1, typename IntType2>
+ friend bool operator>=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2);
+
+private:
+ IntTypeT mCurrent;
+};
+
+template<typename IntType1, typename IntType2>
+bool operator==(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent == aIter2.mCurrent;
+}
+
+template<typename IntType1, typename IntType2>
+bool operator!=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent != aIter2.mCurrent;
+}
+
+template<typename IntType1, typename IntType2>
+bool operator<(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent < aIter2.mCurrent;
+}
+
+template<typename IntType1, typename IntType2>
+bool operator<=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent <= aIter2.mCurrent;
+}
+
+template<typename IntType1, typename IntType2>
+bool operator>(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent > aIter2.mCurrent;
+}
+
+template<typename IntType1, typename IntType2>
+bool operator>=(const IntegerIterator<IntType1>& aIter1,
+ const IntegerIterator<IntType2>& aIter2)
+{
+ return aIter1.mCurrent >= aIter2.mCurrent;
+}
+
+template<typename IntTypeT>
+class IntegerRange
+{
+public:
+ typedef IntegerIterator<IntTypeT> iterator;
+ typedef IntegerIterator<IntTypeT> const_iterator;
+ typedef ReverseIterator<IntegerIterator<IntTypeT>> reverse_iterator;
+ typedef ReverseIterator<IntegerIterator<IntTypeT>> const_reverse_iterator;
+
+ template<typename IntType>
+ explicit IntegerRange(IntType aEnd)
+ : mBegin(0), mEnd(aEnd) { }
+
+ template<typename IntType1, typename IntType2>
+ IntegerRange(IntType1 aBegin, IntType2 aEnd)
+ : mBegin(aBegin), mEnd(aEnd) { }
+
+ iterator begin() const { return iterator(mBegin); }
+ const_iterator cbegin() const { return begin(); }
+ iterator end() const { return iterator(mEnd); }
+ const_iterator cend() const { return end(); }
+ reverse_iterator rbegin() const { return reverse_iterator(mEnd); }
+ const_reverse_iterator crbegin() const { return rbegin(); }
+ reverse_iterator rend() const { return reverse_iterator(mBegin); }
+ const_reverse_iterator crend() const { return rend(); }
+
+private:
+ IntTypeT mBegin;
+ IntTypeT mEnd;
+};
+
+template<typename T, bool = IsUnsigned<T>::value>
+struct GeqZero
+{
+ static bool check(T t) {
+ return t >= 0;
+ }
+};
+
+template<typename T>
+struct GeqZero<T, true>
+{
+ static bool check(T t) {
+ return true;
+ }
+};
+
+} // namespace detail
+
+template<typename IntType>
+detail::IntegerRange<IntType>
+MakeRange(IntType aEnd)
+{
+ MOZ_ASSERT(detail::GeqZero<IntType>::check(aEnd),
+ "Should never have negative value here");
+ return detail::IntegerRange<IntType>(aEnd);
+}
+
+template<typename IntType1, typename IntType2>
+detail::IntegerRange<IntType2>
+MakeRange(IntType1 aBegin, IntType2 aEnd)
+{
+ static_assert(IsSigned<IntType1>::value == IsSigned<IntType2>::value,
+ "signed/unsigned mismatch");
+ MOZ_ASSERT(aEnd >= aBegin, "End value should be larger than begin value");
+ return detail::IntegerRange<IntType2>(aBegin, aEnd);
+}
+
+} // namespace mozilla
+
+#endif // mozilla_IntegerRange_h
diff --git a/mfbt/moz.build b/mfbt/moz.build
index 921bc8d0c1d2f..82b7e7e7fbeae 100644
--- a/mfbt/moz.build
+++ b/mfbt/moz.build
@@ -37,6 +37,7 @@ EXPORTS.mozilla = [
'GuardObjects.h',
'HashFunctions.h',
'IntegerPrintfMacros.h',
+ 'IntegerRange.h',
'IntegerTypeTraits.h',
'IteratorTraits.h',
'JSONWriter.h',
--
GitLab