316 lines
8.6 KiB
C++
316 lines
8.6 KiB
C++
#ifndef MEDIA_OGGITERATOR_H
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#define MEDIA_OGGITERATOR_H
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#include "./oggpage.h"
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#include <iosfwd>
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#include <vector>
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namespace Media {
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class TAG_PARSER_EXPORT OggIterator
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{
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public:
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OggIterator(std::istream &stream, uint64 startOffset, uint64 streamSize);
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void clear(std::istream &stream, uint64 startOffset, uint64 streamSize);
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std::istream &stream();
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void setStream(std::istream &stream);
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uint64 startOffset() const;
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uint64 streamSize() const;
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void reset();
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void nextPage();
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void nextSegment();
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void previousPage();
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void previousSegment();
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const std::vector<OggPage> &pages() const;
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const OggPage ¤tPage() const;
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std::vector<OggPage>::size_type currentPageIndex() const;
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void setPageIndex(std::vector<OggPage>::size_type index);
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void setSegmentIndex(std::vector<uint32>::size_type index);
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std::vector<uint32>::size_type currentSegmentIndex() const;
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uint64 currentSegmentOffset() const;
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uint64 currentCharacterOffset() const;
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uint64 tellg() const;
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uint32 currentSegmentSize() const;
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void setFilter(uint32 streamSerialId);
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void removeFilter();
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bool areAllPagesFetched() const;
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void read(char *buffer, std::size_t count);
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size_t readAll(char *buffer, std::size_t max);
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void ignore(std::size_t count = 1);
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bool bytesRemaining(std::size_t atLeast) const;
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operator bool() const;
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OggIterator &operator++();
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OggIterator operator++(int);
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OggIterator &operator--();
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OggIterator operator--(int);
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private:
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bool fetchNextPage();
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bool matchesFilter(const OggPage &page);
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std::istream *m_stream;
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uint64 m_startOffset;
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uint64 m_streamSize;
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std::vector<OggPage> m_pages;
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std::vector<OggPage>::size_type m_page;
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std::vector<uint32>::size_type m_segment;
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uint64 m_offset;
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uint32 m_bytesRead;
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bool m_hasIdFilter;
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uint32 m_idFilter;
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};
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/*!
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* \brief Constructs a new iterator for the specified \a stream of \a streamSize bytes at the specified \a startOffset.
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*/
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inline OggIterator::OggIterator(std::istream &stream, uint64 startOffset, uint64 streamSize) :
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m_stream(&stream),
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m_startOffset(startOffset),
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m_streamSize(streamSize),
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m_page(0),
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m_segment(0),
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m_offset(0),
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m_bytesRead(0),
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m_hasIdFilter(false),
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m_idFilter(0)
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{}
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/*!
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* \brief Returns the stream.
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*
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* The stream has been specified when constructing the iterator and might be changed using the setStream() methods.
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*/
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inline std::istream &OggIterator::stream()
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{
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return *m_stream;
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}
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/*!
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* \brief Sets the stream.
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* \remarks The new stream must have the same data as the old stream to keep the iterator in a sane state.
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* \sa stream()
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*/
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inline void OggIterator::setStream(std::istream &stream)
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{
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m_stream = &stream;
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}
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/*!
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* \brief Returns the start offset (which has been specified when constructing the iterator).
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*/
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inline uint64 OggIterator::startOffset() const
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{
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return m_startOffset;
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}
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/*!
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* \brief Returns the stream size (which has been specified when constructing the iterator).
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*/
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inline uint64 OggIterator::streamSize() const
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{
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return m_streamSize;
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}
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/*!
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* \brief Returns a vector of containing the OGG pages that have been fetched yet.
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*/
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inline const std::vector<OggPage> &OggIterator::pages() const
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{
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return m_pages;
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}
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/*!
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* \brief Returns the current OGG page.
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* \remarks Calling this method when the iterator is invalid causes undefined behaviour.
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*/
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inline const OggPage &OggIterator::currentPage() const
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{
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return m_pages[m_page];
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}
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/*!
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* \brief Returns an indication whether the iterator is valid.
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*
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* The iterator is invalid when it has just been constructed. Incrementing and decrementing
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* might cause invalidation.
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*
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* If the iterator is invalid, it can be reseted using the reset() method.
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*
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* Some methods might cause undefined behaviour if called on an invalid iterator.
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*/
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inline OggIterator::operator bool() const
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{
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return m_page < m_pages.size() && m_segment < m_pages[m_page].segmentSizes().size();
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}
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/*!
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* \brief Returns the index of the current page if the iterator is valid; otherwise an undefined index is returned.
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*/
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inline std::vector<OggPage>::size_type OggIterator::currentPageIndex() const
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{
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return m_page;
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}
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/*!
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* \brief Sets the current page index.
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*
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* This method should never be called with an \a index out of range (which is the defined by the number of fetched pages), since this causes undefined behaviour.
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*/
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inline void OggIterator::setPageIndex(std::vector<OggPage>::size_type index)
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{
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const OggPage &page = m_pages[m_page = index];
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m_segment = 0;
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m_offset = page.startOffset() + page.headerSize();
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}
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/*!
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* \brief Sets the current segment index.
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*
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* This method should never be called with an \a index out of range (which is defined by the number of segments in the current page), since this causes undefined behaviour.
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*/
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inline void OggIterator::setSegmentIndex(std::vector<uint32>::size_type index)
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{
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const OggPage &page = m_pages[m_page];
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m_offset = page.dataOffset(m_segment = index);
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}
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/*!
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* \brief Returns the index of the current segment (in the current page) if the iterator is valid; otherwise an undefined index is returned.
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*/
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inline std::vector<uint32>::size_type OggIterator::currentSegmentIndex() const
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{
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return m_segment;
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}
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/*!
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* \brief Returns the start offset of the current segment in the input stream if the iterator is valid; otherwise an undefined offset is returned.
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* \sa currentCharacterOffset()
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*/
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inline uint64 OggIterator::currentSegmentOffset() const
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{
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return m_offset;
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}
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/*!
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* \brief Returns the offset of the current character in the input stream if the iterator is valid; otherwise an undefined offset is returned.
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* \sa currentSegmentOffset()
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*/
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inline uint64 OggIterator::currentCharacterOffset() const
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{
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return m_offset + m_bytesRead;
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}
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/*!
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* \brief Same as currentCharacterOffset(); only provided for compliance with std::istream.
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*/
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inline uint64 OggIterator::tellg() const
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{
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return currentCharacterOffset();
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}
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/*!
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* \brief Returns the size of the current segment.
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*
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* This method should never be called on an invalid iterator, since this causes undefined behaviour.
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*/
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inline uint32 OggIterator::currentSegmentSize() const
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{
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return m_pages[m_page].segmentSizes()[m_segment];
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}
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/*!
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* \brief Allows to filter pages by the specified \a streamSerialId.
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*
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* Pages which do not match the specified \a streamSerialId will be skipped when getting the previous or
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* the next page.
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*
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* \sa removeFilter()
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*/
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inline void OggIterator::setFilter(uint32 streamSerialId)
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{
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m_hasIdFilter = true;
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m_idFilter = streamSerialId;
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}
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/*!
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* \brief Removes a previously set filter.
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* \sa setFilter()
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*/
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inline void OggIterator::removeFilter()
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{
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m_hasIdFilter = false;
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}
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/*!
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* \brief Returns an indication whether all pages have been fetched.
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*
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* This means that for each page in the stream in the specified range (stream and range have been specified when
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* constructing the iterator) an OggPage instance has been created and pushed to pages(). This is independend from
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* the current iterator position. Fetched pages remain after resetting the iterator.
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*/
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inline bool OggIterator::areAllPagesFetched() const
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{
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return (m_pages.empty() ? m_startOffset : m_pages.back().startOffset() + m_pages.back().totalSize()) >= m_streamSize;
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}
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/*!
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* \brief Returns whether there are \a atLeast bytes remaining.
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*/
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inline bool OggIterator::bytesRemaining(size_t atLeast) const
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{
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return *this && currentCharacterOffset() + atLeast <= streamSize();
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}
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/*!
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* \brief Increments the current position by one segment if the iterator is valid; otherwise nothing happens.
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*/
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inline OggIterator &OggIterator::operator++()
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{
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nextSegment();
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return *this;
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}
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/*!
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* \brief Increments the current position by one segment if the iterator is valid; otherwise nothing happens.
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*/
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inline OggIterator OggIterator::operator++(int)
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{
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OggIterator tmp = *this;
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nextSegment();
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return tmp;
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}
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/*!
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* \brief Decrements the current position by one segment if the iterator is valid; otherwise nothing happens.
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*/
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inline OggIterator &OggIterator::operator--()
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{
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previousSegment();
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return *this;
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}
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/*!
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* \brief Decrements the current position by one segment if the iterator is valid; otherwise nothing happens.
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*/
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inline OggIterator OggIterator::operator--(int)
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{
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OggIterator tmp = *this;
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previousSegment();
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return tmp;
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}
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/*!
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* \brief Returns whether the specified \a page matches the current filter.
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*/
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inline bool OggIterator::matchesFilter(const OggPage &page)
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{
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return !m_hasIdFilter || m_idFilter == page.streamSerialNumber();
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}
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}
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#endif // MEDIA_OGGITERATOR_H
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