wiscdb::PageIterator Class Reference

Iterator for iterating over the records in a page. More...

#include <page_iterator.h>

Public Member Functions
	PageIterator ()
	PageIterator (Page *page)
	PageIterator (Page *page, const RecordId &record_id)
PageIterator &	operator++ ()
PageIterator	operator++ (int)
bool	operator== (const PageIterator &rhs) const
bool	operator!= (const PageIterator &rhs) const
std::string	operator* () const
SlotId	getNextUsedSlot (const SlotId start) const

Detailed Description

Iterator for iterating over the records in a page.

This class provides a forward-only iterator that iterates over all the records stored in a Page.

Definition at line 23 of file page_iterator.h.

Constructor & Destructor Documentation

wiscdb::PageIterator::PageIterator ( )

inline

Constructs an empty iterator.

Definition at line 28 of file page_iterator.h.

      : page_(NULL) {
    current_record_ = {Page::INVALID_NUMBER, Page::INVALID_SLOT};
  }

wiscdb::PageIterator::PageIterator ( Page *  page )

inline

Constructs an iterator over the records in the given page, starting at the first record. Page must not be null.

Parameters

page	Page to iterate over.

Definition at line 39 of file page_iterator.h.

      : page_(page)  {
    assert(page_ != NULL);
    const SlotId used_slot = getNextUsedSlot(Page::INVALID_SLOT /* start */);
    current_record_ = {page_->page_number(), used_slot};
  }

wiscdb::PageIterator::PageIterator ( Page *  page, const RecordId &  record_id  )

inline

Constructs an iterator over the records in the given page, starting at the given record.

Parameters

page	Page to iterate over.
record_id	ID of record to start iterator at.

Definition at line 53 of file page_iterator.h.

      : page_(page),
        current_record_(record_id) {
  }

Member Function Documentation

SlotId wiscdb::PageIterator::getNextUsedSlot ( const SlotId  start ) const

inline

Returns the next used slot in the page after the given slot or Page::INVALID_SLOT if no slots are used after the given slot.

Parameters

start

Slot to start search at.

Returns

Next used slot after given slot or Page::INVALID_SLOT.

Definition at line 111 of file page_iterator.h.

                                                   {
    SlotId slot_number = Page::INVALID_SLOT;
    for (SlotId i = start + 1; i <= page_->header.num_slots; ++i) {
      const PageSlot* slot = page_->getSlot(i);
      if (slot->used) {
        slot_number = i;
        break;
      }
    }
    return slot_number;
  }

std::string wiscdb::PageIterator::operator* ( ) const

inline

Dereferences the iterator, returning a copy of the current record in the page.

Returns

Record in page.

Definition at line 100 of file page_iterator.h.

                                     {
    return page_->getRecord(current_record_); 
  }

PageIterator& wiscdb::PageIterator::operator++ ( )

inline

Advances the iterator to the next record in the page.

Definition at line 61 of file page_iterator.h.

                                    {
    assert(page_ != NULL);
    const SlotId used_slot = getNextUsedSlot(current_record_.slot_number);
    current_record_ = {page_->page_number(), used_slot};

    return *this;
  }

bool wiscdb::PageIterator::operator== ( const PageIterator &  rhs ) const

inline

Returns true if this iterator is equal to the given iterator.

Parameters

rhs	Iterator to compare against.

Returns

True if other iterator is equal to this one.

Definition at line 84 of file page_iterator.h.

                                                        {
    return page_->page_number() == rhs.page_->page_number() &&
        current_record_ == rhs.current_record_;
  }

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The documentation for this class was generated from the following file:

• page_iterator.h