summaryrefslogtreecommitdiffstats
path: root/xpcom/string/nsStringIterator.h
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--xpcom/string/nsStringIterator.h117
1 files changed, 117 insertions, 0 deletions
diff --git a/xpcom/string/nsStringIterator.h b/xpcom/string/nsStringIterator.h
new file mode 100644
index 0000000000..db14efdaca
--- /dev/null
+++ b/xpcom/string/nsStringIterator.h
@@ -0,0 +1,117 @@
+/* -*- 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 nsStringIterator_h___
+#define nsStringIterator_h___
+
+#include "nsCharTraits.h"
+#include "nsAlgorithm.h"
+#include "nsDebug.h"
+
+/**
+ * @see nsTAString
+ */
+
+template <class CharT>
+class nsReadingIterator {
+ public:
+ typedef nsReadingIterator<CharT> self_type;
+ typedef ptrdiff_t difference_type;
+ typedef size_t size_type;
+ typedef CharT value_type;
+ typedef const CharT* pointer;
+ typedef const CharT& reference;
+
+ private:
+ friend class mozilla::detail::nsTStringRepr<CharT>;
+
+ // unfortunately, the API for nsReadingIterator requires that the
+ // iterator know its start and end positions. this was needed when
+ // we supported multi-fragment strings, but now it is really just
+ // extra baggage. we should remove mStart and mEnd at some point.
+
+ const CharT* mStart;
+ const CharT* mEnd;
+ const CharT* mPosition;
+
+ public:
+ nsReadingIterator() : mStart(nullptr), mEnd(nullptr), mPosition(nullptr) {}
+ // clang-format off
+ // nsReadingIterator( const nsReadingIterator<CharT>& ); // auto-generated copy-constructor OK
+ // nsReadingIterator<CharT>& operator=( const nsReadingIterator<CharT>& ); // auto-generated copy-assignment operator OK
+ // clang-format on
+
+ pointer get() const { return mPosition; }
+
+ CharT operator*() const { return *get(); }
+
+ self_type& operator++() {
+ ++mPosition;
+ return *this;
+ }
+
+ self_type operator++(int) {
+ self_type result(*this);
+ ++mPosition;
+ return result;
+ }
+
+ self_type& operator--() {
+ --mPosition;
+ return *this;
+ }
+
+ self_type operator--(int) {
+ self_type result(*this);
+ --mPosition;
+ return result;
+ }
+
+ self_type& advance(difference_type aN) {
+ if (aN > 0) {
+ difference_type step = XPCOM_MIN(aN, mEnd - mPosition);
+
+ NS_ASSERTION(
+ step > 0,
+ "can't advance a reading iterator beyond the end of a string");
+
+ mPosition += step;
+ } else if (aN < 0) {
+ difference_type step = XPCOM_MAX(aN, -(mPosition - mStart));
+
+ NS_ASSERTION(step < 0,
+ "can't advance (backward) a reading iterator beyond the end "
+ "of a string");
+
+ mPosition += step;
+ }
+ return *this;
+ }
+
+ // We return an unsigned type here (with corresponding assert) rather than
+ // the more usual difference_type because we want to make this class go
+ // away in favor of mozilla::RangedPtr. Since RangedPtr has the same
+ // requirement we are enforcing here, the transition ought to be much
+ // smoother.
+ size_type operator-(const self_type& aOther) const {
+ MOZ_ASSERT(mPosition >= aOther.mPosition);
+ return mPosition - aOther.mPosition;
+ }
+};
+
+template <class CharT>
+inline bool operator==(const nsReadingIterator<CharT>& aLhs,
+ const nsReadingIterator<CharT>& aRhs) {
+ return aLhs.get() == aRhs.get();
+}
+
+template <class CharT>
+inline bool operator!=(const nsReadingIterator<CharT>& aLhs,
+ const nsReadingIterator<CharT>& aRhs) {
+ return aLhs.get() != aRhs.get();
+}
+
+#endif /* !defined(nsStringIterator_h___) */