forked from mirrors/gecko-dev
265e672179
# ignore-this-changeset --HG-- extra : amend_source : 4d301d3b0b8711c4692392aa76088ba7fd7d1022
117 lines
3.3 KiB
C++
117 lines
3.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsStringIterator_h___
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#define nsStringIterator_h___
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#include "nsCharTraits.h"
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#include "nsAlgorithm.h"
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#include "nsDebug.h"
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/**
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* @see nsTAString
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*/
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template <class CharT>
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class nsReadingIterator {
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public:
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typedef nsReadingIterator<CharT> self_type;
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typedef ptrdiff_t difference_type;
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typedef size_t size_type;
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typedef CharT value_type;
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typedef const CharT* pointer;
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typedef const CharT& reference;
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private:
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friend class mozilla::detail::nsTStringRepr<CharT>;
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// unfortunately, the API for nsReadingIterator requires that the
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// iterator know its start and end positions. this was needed when
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// we supported multi-fragment strings, but now it is really just
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// extra baggage. we should remove mStart and mEnd at some point.
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const CharT* mStart;
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const CharT* mEnd;
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const CharT* mPosition;
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public:
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nsReadingIterator() : mStart(nullptr), mEnd(nullptr), mPosition(nullptr) {}
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// clang-format off
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// nsReadingIterator( const nsReadingIterator<CharT>& ); // auto-generated copy-constructor OK
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// nsReadingIterator<CharT>& operator=( const nsReadingIterator<CharT>& ); // auto-generated copy-assignment operator OK
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// clang-format on
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pointer get() const { return mPosition; }
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CharT operator*() const { return *get(); }
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self_type& operator++() {
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++mPosition;
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return *this;
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}
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self_type operator++(int) {
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self_type result(*this);
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++mPosition;
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return result;
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}
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self_type& operator--() {
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--mPosition;
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return *this;
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}
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self_type operator--(int) {
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self_type result(*this);
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--mPosition;
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return result;
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}
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self_type& advance(difference_type aN) {
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if (aN > 0) {
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difference_type step = XPCOM_MIN(aN, mEnd - mPosition);
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NS_ASSERTION(
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step > 0,
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"can't advance a reading iterator beyond the end of a string");
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mPosition += step;
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} else if (aN < 0) {
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difference_type step = XPCOM_MAX(aN, -(mPosition - mStart));
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NS_ASSERTION(step < 0,
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"can't advance (backward) a reading iterator beyond the end "
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"of a string");
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mPosition += step;
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}
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return *this;
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}
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// We return an unsigned type here (with corresponding assert) rather than
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// the more usual difference_type because we want to make this class go
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// away in favor of mozilla::RangedPtr. Since RangedPtr has the same
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// requirement we are enforcing here, the transition ought to be much
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// smoother.
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size_type operator-(const self_type& aOther) const {
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MOZ_ASSERT(mPosition >= aOther.mPosition);
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return mPosition - aOther.mPosition;
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}
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};
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template <class CharT>
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inline bool operator==(const nsReadingIterator<CharT>& aLhs,
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const nsReadingIterator<CharT>& aRhs) {
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return aLhs.get() == aRhs.get();
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}
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template <class CharT>
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inline bool operator!=(const nsReadingIterator<CharT>& aLhs,
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const nsReadingIterator<CharT>& aRhs) {
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return aLhs.get() != aRhs.get();
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}
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#endif /* !defined(nsStringIterator_h___) */
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