stasis-aries-wal/stasis/page/slotted.h

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/************************************************************************
* @file implementation of variable-sized slotted pages
STRUCTURE OF A PAGE
<pre>
+-----------------------------------------+-----------------------+----+
| DATA SECTION +--------->| RID: (PAGE, 0) | |
| +-----------------+ | +-----------------------+ |
| +-->| RID: (PAGE, 1) | | |
| | +-----------------+ | |
| | | |
| ----------------+ | +------------------------------+
| | | +--->| RID: (PAGE, n) |
| | | | +------------------------------+
|======================================================================|
| ^ FREE SPACE | | | |
| | | | | |
| +-------------------|-------|---|--------------------+ |
| | | | | |
| +-------------|-------|---+ | |
| | | | | |
| +---|---+-----+---|---+---|---+--------------+-----|------+-------+
| | slotn | ... | slot1 | slot0 | num of slots | free space | *** |
+----+-------+-----+-------+-------+--------------+------------+-------+
</pre>
*** = @see page.h for information on this field.
NOTE:
- slots are zero indexed.
- slots are of implemented as (offset, length)
Slotted page layout:
END:
lsn (4 bytes)
type (2 bytes)
free space (2 bytes)
num of slots (2 bytes)
freelist head(2 bytes)
slot 0 (4 bytes)
slot 1 (4 bytes)
...
slot n (4 bytes)
...
unused
...
record n (x bytes)
...
record 0 (y bytes)
record 1 (z bytes)
START
$Id$
2006-06-13 22:46:11 +00:00
@todo slotted.c Should know that specific record types (like blobs) exist,
(but should not hardcode information about these types) This
has been handled, except in slottedPostRalloc...
2006-06-13 22:46:11 +00:00
************************************************************************/
static inline int16_t* stasis_page_slotted_freespace_ptr(Page * p) { return stasis_page_int16_ptr_from_end((p), 1); }
static inline int16_t* stasis_page_slotted_numslots_ptr(Page * p) { return stasis_page_int16_ptr_from_end(p, 2); }
static inline int16_t* stasis_page_slotted_freelist_ptr(Page * p) { return stasis_page_int16_ptr_from_end(p, 3); }
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); }
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); }
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))); }
static inline const int16_t* stasis_page_slotted_freespace_cptr(const Page * p) { return stasis_page_slotted_freespace_ptr((Page*)p); }
static inline const int16_t* stasis_page_slotted_numslots_cptr(const Page * p) { return stasis_page_slotted_numslots_ptr((Page*)p); }
static inline const int16_t* stasis_page_slotted_freelist_cptr(const Page * p) { return stasis_page_slotted_freelist_ptr((Page*)p); }
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); }
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); }
static inline const byte* stasis_page_slotted_record_cptr(const Page * p, slotid_t n) { return stasis_page_slotted_record_ptr((Page*)p, n); }
void stasis_page_slotted_init();
void stasis_page_slotted_deinit();
page_impl stasis_page_slotted_impl();
page_impl stasis_page_boundary_tag_impl();