VarlenDataPage.h

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#ifndef STORAGE_VARLENDATAPAGE_H
#define STORAGE_VARLENDATAPAGE_H
 
#include "tdb.h"
 
#include "storage/Record.h"
 
namespace taco {
 
struct SlotData;
 
static_assert(MinSlotId == 1);
 
class VarlenDataPage {
public:
    static void InitializePage(char *pagebuf, FieldOffset usr_data_sz = 0);
 
    VarlenDataPage(char *pagebuf);
 
    char* GetUserData() const;
 
    constexpr SlotId
    GetMinSlotId() const {
        return MinSlotId;
    }
 
    SlotId GetMaxSlotId() const;
 
    SlotId
    GetMinOccupiedSlotId() const {
        for (SlotId sid = GetMinSlotId(); sid <= GetMaxSlotId(); ++sid) {
            if (IsOccupied(sid)) {
                return sid;
            }
        }
        return INVALID_SID;
    }
 
    SlotId
    GetMaxOccupiedSlotId() const {
        return GetMaxSlotId();
    }
 
    bool IsOccupied(SlotId sid) const;
 
    SlotId GetRecordCount() const;
 
    char *GetRecordBuffer(SlotId sid, FieldOffset *p_len) const;
 
    Record
    GetRecord(SlotId sid) const {
        Record rec;
        rec.GetData() = GetRecordBuffer(sid, &rec.GetLength());
        rec.GetRecordId().sid = sid;
        return rec;
    }
 
    bool InsertRecord(Record &rec);
 
    bool EraseRecord(SlotId sid);
 
    bool UpdateRecord(SlotId sid, Record &rec);
 
    bool InsertRecordAt(SlotId sid, Record &rec);
 
    void RemoveSlot(SlotId sid);
 
    void ShiftSlots(SlotId n, bool truncate);
 
    static FieldOffset ComputeFreeSpace(FieldOffset usr_data_sz,
                                        SlotId num_recs,
                                        FieldOffset total_reclen);
private:
    inline void
    CheckSID(SlotId sid) const {
        if (sid < GetMinSlotId() || sid > GetMaxSlotId()) {
            LOG(kError, "sid is out of range, got " SLOTID_FORMAT " but "
                        "expecting in [" SLOTID_FORMAT ", " SLOTID_FORMAT "]",
                        sid, GetMinSlotId(), GetMaxSlotId());
        }
    }
 
 
    constexpr SlotData*
    GetSlotArray() const {
        return (SlotData*)(m_pagebuf + PAGE_SIZE);
    }
 
    void PutRecordIntoSlot(SlotId sid, Record &rec);
 
    void CompactSpace();
 
    char *m_pagebuf;
};
 
}   // namespace taco
 
#endif  // STORAGE_VARLENDATAPAGE_H