80 lines
4 KiB
C
80 lines
4 KiB
C
/************************************************************************
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* @file implementation of variable-sized slotted pages
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STRUCTURE OF A PAGE
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<pre>
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+-----------------------------------------+-----------------------+----+
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| DATA SECTION +--------->| RID: (PAGE, 0) | |
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| +-----------------+ | +-----------------------+ |
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| +-->| RID: (PAGE, 1) | | |
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| | +-----------------+ | |
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| | | |
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| ----------------+ | +------------------------------+
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| | | +--->| RID: (PAGE, n) |
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| | | | +------------------------------+
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|======================================================================|
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| ^ FREE SPACE | | | |
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| | | | | |
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| +-------------------|-------|---|--------------------+ |
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| | | | | |
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| +-------------|-------|---+ | |
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| | | | | |
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| +---|---+-----+---|---+---|---+--------------+-----|------+-------+
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| | slotn | ... | slot1 | slot0 | num of slots | free space | *** |
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+----+-------+-----+-------+-------+--------------+------------+-------+
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</pre>
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*** = @see page.h for information on this field.
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NOTE:
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- slots are zero indexed.
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- slots are of implemented as (offset, length)
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Slotted page layout:
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END:
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lsn (4 bytes)
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type (2 bytes)
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free space (2 bytes)
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num of slots (2 bytes)
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freelist head(2 bytes)
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slot 0 (4 bytes)
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slot 1 (4 bytes)
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...
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slot n (4 bytes)
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...
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unused
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...
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record n (x bytes)
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...
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record 0 (y bytes)
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record 1 (z bytes)
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START
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$Id$
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@todo slotted.c Should know that specific record types (like blobs) exist,
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(but should not hardcode information about these types) This
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has been handled, except in slottedPostRalloc...
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************************************************************************/
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static inline int16_t* stasis_page_slotted_freespace_ptr(Page * p) { return stasis_page_int16_ptr_from_end((p), 1); }
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static inline int16_t* stasis_page_slotted_numslots_ptr(Page * p) { return stasis_page_int16_ptr_from_end(p, 2); }
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static inline int16_t* stasis_page_slotted_freelist_ptr(Page * p) { return stasis_page_int16_ptr_from_end(p, 3); }
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static inline int16_t* stasis_page_slotted_slot_ptr(Page * p, slotid_t n) { return stasis_page_int16_ptr_from_end(p, (2*(n))+4); }
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static inline int16_t* stasis_page_slotted_slot_length_ptr(Page * p, slotid_t n) { return stasis_page_int16_ptr_from_end((p), (2*(n))+5); }
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static inline byte* stasis_page_slotted_record_ptr(Page * p, slotid_t n) { return stasis_page_byte_ptr_from_start((p), *stasis_page_slotted_slot_ptr((p), (n))); }
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static inline const int16_t* stasis_page_slotted_freespace_cptr(const Page * p) { return stasis_page_slotted_freespace_ptr((Page*)p); }
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static inline const int16_t* stasis_page_slotted_numslots_cptr(const Page * p) { return stasis_page_slotted_numslots_ptr((Page*)p); }
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static inline const int16_t* stasis_page_slotted_freelist_cptr(const Page * p) { return stasis_page_slotted_freelist_ptr((Page*)p); }
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static inline const int16_t* stasis_page_slotted_slot_cptr(const Page * p, slotid_t n) { return stasis_page_slotted_slot_ptr((Page*)p, n); }
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static inline const int16_t* stasis_page_slotted_slot_length_cptr(const Page * p, slotid_t n) { return stasis_page_slotted_slot_length_ptr((Page*)p, n); }
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static inline const byte* stasis_page_slotted_record_cptr(const Page * p, slotid_t n) { return stasis_page_slotted_record_ptr((Page*)p, n); }
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void stasis_page_slotted_init();
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void stasis_page_slotted_deinit();
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page_impl stasis_page_slotted_impl();
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page_impl stasis_page_boundary_tag_impl();
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