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Diffstat (limited to 'xpcom/string/nsStringIterator.h')
| -rw-r--r-- | xpcom/string/nsStringIterator.h | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/xpcom/string/nsStringIterator.h b/xpcom/string/nsStringIterator.h new file mode 100644 index 000000000..e309a21e9 --- /dev/null +++ b/xpcom/string/nsStringIterator.h @@ -0,0 +1,268 @@ +/* -*- 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 nsAString; + friend class nsACString; + + // 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() + { + } + // nsReadingIterator( const nsReadingIterator<CharT>& ); // auto-generated copy-constructor OK + // nsReadingIterator<CharT>& operator=( const nsReadingIterator<CharT>& ); // auto-generated copy-assignment operator OK + + 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; + } +}; + +/** + * @see nsTAString + */ + +template <class CharT> +class nsWritingIterator +{ +public: + typedef nsWritingIterator<CharT> self_type; + typedef ptrdiff_t difference_type; + typedef size_t size_type; + typedef CharT value_type; + typedef CharT* pointer; + typedef CharT& reference; + +private: + friend class nsAString; + friend class nsACString; + + // unfortunately, the API for nsWritingIterator 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. + + CharT* mStart; + CharT* mEnd; + CharT* mPosition; + +public: + nsWritingIterator() + { + } + // nsWritingIterator( const nsWritingIterator<CharT>& ); // auto-generated copy-constructor OK + // nsWritingIterator<CharT>& operator=( const nsWritingIterator<CharT>& ); // auto-generated copy-assignment operator OK + + pointer get() const + { + return mPosition; + } + + reference 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 writing 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 writing 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> +struct nsCharSinkTraits<nsWritingIterator<CharT>> +{ + static void + write(nsWritingIterator<CharT>& aIter, const CharT* aStr, uint32_t aN) + { + nsCharTraits<CharT>::move(aIter.get(), aStr, aN); + aIter.advance(aN); + } +}; + +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(); +} + + +// +// |nsWritingIterator|s +// + +template <class CharT> +inline bool +operator==(const nsWritingIterator<CharT>& aLhs, + const nsWritingIterator<CharT>& aRhs) +{ + return aLhs.get() == aRhs.get(); +} + +template <class CharT> +inline bool +operator!=(const nsWritingIterator<CharT>& aLhs, + const nsWritingIterator<CharT>& aRhs) +{ + return aLhs.get() != aRhs.get(); +} + +#endif /* !defined(nsStringIterator_h___) */ |