/*
* mask_page_hint_bits
*
* Mask hint bits in PageHeader. We want to ignore differences in hint bits,
* since they can be set without emitting any WAL.
*/
void
mask_page_hint_bits(Page page)
{
PageHeader phdr = (PageHeader) page;
/* Ignore prune_xid (it's like a hint-bit) */
phdr->pd_prune_xid = MASK_MARKER;
/* Ignore PD_PAGE_FULL and PD_HAS_FREE_LINES flags, they are just hints. */
PageClearFull(page);
PageClearHasFreeLinePointers(page);
/*
* During replay, if the page LSN has advanced past our XLOG record's LSN,
* we don't mark the page all-visible. See heap_xlog_visible() for
* details.
*/
PageClearAllVisible(page);
}
/*
* PageRepairFragmentation
*
* Frees fragmented space on a page.
* It doesn't remove unused line pointers! Please don't change this.
*
* This routine is usable for heap pages only, but see PageIndexMultiDelete.
*
* As a side effect, the page's PD_HAS_FREE_LINES hint bit is updated.
*/
void
PageRepairFragmentation(Page page)
{
Offset pd_lower = ((PageHeader) page)->pd_lower;
Offset pd_upper = ((PageHeader) page)->pd_upper;
Offset pd_special = ((PageHeader) page)->pd_special;
ItemId lp;
int nline,
nstorage,
nunused;
int i;
Size totallen;
/*
* It's worth the trouble to be more paranoid here than in most places,
* because we are about to reshuffle data in (what is usually) a shared
* disk buffer. If we aren't careful then corrupted pointers, lengths,
* etc could cause us to clobber adjacent disk buffers, spreading the data
* loss further. So, check everything.
*/
if (pd_lower < SizeOfPageHeaderData ||
pd_lower > pd_upper ||
pd_upper > pd_special ||
pd_special > BLCKSZ ||
pd_special != MAXALIGN(pd_special))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
pd_lower, pd_upper, pd_special)));
nline = PageGetMaxOffsetNumber(page);
nunused = nstorage = 0;
for (i = FirstOffsetNumber; i <= nline; i++)
{
lp = PageGetItemId(page, i);
if (ItemIdIsUsed(lp))
{
if (ItemIdHasStorage(lp))
nstorage++;
}
else
{
/* Unused entries should have lp_len = 0, but make sure */
ItemIdSetUnused(lp);
nunused++;
}
}
if (nstorage == 0)
{
/* Page is completely empty, so just reset it quickly */
((PageHeader) page)->pd_upper = pd_special;
}
else
{
/* Need to compact the page the hard way */
itemIdSortData itemidbase[MaxHeapTuplesPerPage];
itemIdSort itemidptr = itemidbase;
totallen = 0;
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
if (ItemIdHasStorage(lp))
{
itemidptr->offsetindex = i;
itemidptr->itemoff = ItemIdGetOffset(lp);
if (itemidptr->itemoff < (int) pd_upper ||
itemidptr->itemoff >= (int) pd_special)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item pointer: %u",
itemidptr->itemoff)));
itemidptr->alignedlen = MAXALIGN(ItemIdGetLength(lp));
totallen += itemidptr->alignedlen;
itemidptr++;
}
}
if (totallen > (Size) (pd_special - pd_lower))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item lengths: total %u, available space %u",
(unsigned int) totallen, pd_special - pd_lower)));
compactify_tuples(itemidbase, nstorage, page);
}
/* Set hint bit for PageAddItem */
if (nunused > 0)
PageSetHasFreeLinePointers(page);
else
PageClearHasFreeLinePointers(page);
}
/*
* PageAddItemExtended
*
* Add an item to a page. Return value is the offset at which it was
* inserted, or InvalidOffsetNumber if the item is not inserted for any
* reason. A WARNING is issued indicating the reason for the refusal.
*
* offsetNumber must be either InvalidOffsetNumber to specify finding a
* free item pointer, or a value between FirstOffsetNumber and one past
* the last existing item, to specify using that particular item pointer.
*
* If offsetNumber is valid and flag PAI_OVERWRITE is set, we just store
* the item at the specified offsetNumber, which must be either a
* currently-unused item pointer, or one past the last existing item.
*
* If offsetNumber is valid and flag PAI_OVERWRITE is not set, insert
* the item at the specified offsetNumber, moving existing items later
* in the array to make room.
*
* If offsetNumber is not valid, then assign a slot by finding the first
* one that is both unused and deallocated.
*
* If flag PAI_IS_HEAP is set, we enforce that there can't be more than
* MaxHeapTuplesPerPage line pointers on the page.
*
* !!! EREPORT(ERROR) IS DISALLOWED HERE !!!
*/
OffsetNumber
PageAddItemExtended(Page page,
Item item,
Size size,
OffsetNumber offsetNumber,
int flags)
{
PageHeader phdr = (PageHeader) page;
Size alignedSize;
int lower;
int upper;
ItemId itemId;
OffsetNumber limit;
bool needshuffle = false;
/*
* Be wary about corrupted page pointers
*/
if (phdr->pd_lower < SizeOfPageHeaderData ||
phdr->pd_lower > phdr->pd_upper ||
phdr->pd_upper > phdr->pd_special ||
phdr->pd_special > BLCKSZ)
ereport(PANIC,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
phdr->pd_lower, phdr->pd_upper, phdr->pd_special)));
/*
* Select offsetNumber to place the new item at
*/
limit = OffsetNumberNext(PageGetMaxOffsetNumber(page));
/* was offsetNumber passed in? */
if (OffsetNumberIsValid(offsetNumber))
{
/* yes, check it */
if ((flags & PAI_OVERWRITE) != 0)
{
if (offsetNumber < limit)
{
itemId = PageGetItemId(phdr, offsetNumber);
if (ItemIdIsUsed(itemId) || ItemIdHasStorage(itemId))
{
elog(WARNING, "will not overwrite a used ItemId");
return InvalidOffsetNumber;
}
}
}
else
{
if (offsetNumber < limit)
needshuffle = true; /* need to move existing linp's */
}
}
else
{
/* offsetNumber was not passed in, so find a free slot */
/* if no free slot, we'll put it at limit (1st open slot) */
if (PageHasFreeLinePointers(phdr))
{
/*
* Look for "recyclable" (unused) ItemId. We check for no storage
* as well, just to be paranoid --- unused items should never have
* storage.
*/
for (offsetNumber = 1; offsetNumber < limit; offsetNumber++)
{
itemId = PageGetItemId(phdr, offsetNumber);
if (!ItemIdIsUsed(itemId) && !ItemIdHasStorage(itemId))
break;
}
if (offsetNumber >= limit)
{
/* the hint is wrong, so reset it */
PageClearHasFreeLinePointers(phdr);
}
}
else
{
/* don't bother searching if hint says there's no free slot */
offsetNumber = limit;
}
}
/* Reject placing items beyond the first unused line pointer */
if (offsetNumber > limit)
{
elog(WARNING, "specified item offset is too large");
return InvalidOffsetNumber;
}
/* Reject placing items beyond heap boundary, if heap */
if ((flags & PAI_IS_HEAP) != 0 && offsetNumber > MaxHeapTuplesPerPage)
{
elog(WARNING, "can't put more than MaxHeapTuplesPerPage items in a heap page");
return InvalidOffsetNumber;
}
/*
* Compute new lower and upper pointers for page, see if it'll fit.
*
* Note: do arithmetic as signed ints, to avoid mistakes if, say,
* alignedSize > pd_upper.
*/
if (offsetNumber == limit || needshuffle)
lower = phdr->pd_lower + sizeof(ItemIdData);
else
lower = phdr->pd_lower;
alignedSize = MAXALIGN(size);
upper = (int) phdr->pd_upper - (int) alignedSize;
if (lower > upper)
return InvalidOffsetNumber;
/*
* OK to insert the item. First, shuffle the existing pointers if needed.
*/
itemId = PageGetItemId(phdr, offsetNumber);
if (needshuffle)
memmove(itemId + 1, itemId,
(limit - offsetNumber) * sizeof(ItemIdData));
/* set the item pointer */
ItemIdSetNormal(itemId, upper, size);
/*
* Items normally contain no uninitialized bytes. Core bufpage consumers
* conform, but this is not a necessary coding rule; a new index AM could
* opt to depart from it. However, data type input functions and other
* C-language functions that synthesize datums should initialize all
* bytes; datumIsEqual() relies on this. Testing here, along with the
* similar check in printtup(), helps to catch such mistakes.
*
* Values of the "name" type retrieved via index-only scans may contain
* uninitialized bytes; see comment in btrescan(). Valgrind will report
* this as an error, but it is safe to ignore.
*/
VALGRIND_CHECK_MEM_IS_DEFINED(item, size);
/* copy the item's data onto the page */
memcpy((char *) page + upper, item, size);
/* adjust page header */
phdr->pd_lower = (LocationIndex) lower;
phdr->pd_upper = (LocationIndex) upper;
return offsetNumber;
}
/*
* PageIndexDeleteNoCompact
* Delete the given items for an index page, and defragment the resulting
* free space, but do not compact the item pointers array.
*
* itemnos is the array of tuples to delete; nitems is its size. maxIdxTuples
* is the maximum number of tuples that can exist in a page.
*
* Unused items at the end of the array are removed.
*
* This is used for index AMs that require that existing TIDs of live tuples
* remain unchanged.
*/
void
PageIndexDeleteNoCompact(Page page, OffsetNumber *itemnos, int nitems)
{
PageHeader phdr = (PageHeader) page;
LocationIndex pd_lower = phdr->pd_lower;
LocationIndex pd_upper = phdr->pd_upper;
LocationIndex pd_special = phdr->pd_special;
int nline;
bool empty;
OffsetNumber offnum;
int nextitm;
/*
* As with PageRepairFragmentation, paranoia seems justified.
*/
if (pd_lower < SizeOfPageHeaderData ||
pd_lower > pd_upper ||
pd_upper > pd_special ||
pd_special > BLCKSZ ||
pd_special != MAXALIGN(pd_special))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
pd_lower, pd_upper, pd_special)));
/*
* Scan the existing item pointer array and mark as unused those that are
* in our kill-list; make sure any non-interesting ones are marked unused
* as well.
*/
nline = PageGetMaxOffsetNumber(page);
empty = true;
nextitm = 0;
for (offnum = FirstOffsetNumber; offnum <= nline; offnum = OffsetNumberNext(offnum))
{
ItemId lp;
ItemLength itemlen;
ItemOffset offset;
lp = PageGetItemId(page, offnum);
itemlen = ItemIdGetLength(lp);
offset = ItemIdGetOffset(lp);
if (ItemIdIsUsed(lp))
{
if (offset < pd_upper ||
(offset + itemlen) > pd_special ||
offset != MAXALIGN(offset))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item pointer: offset = %u, length = %u",
offset, (unsigned int) itemlen)));
if (nextitm < nitems && offnum == itemnos[nextitm])
{
/* this one is on our list to delete, so mark it unused */
ItemIdSetUnused(lp);
nextitm++;
}
else if (ItemIdHasStorage(lp))
{
/* This one's live -- must do the compaction dance */
empty = false;
}
else
{
/* get rid of this one too */
ItemIdSetUnused(lp);
}
}
}
/* this will catch invalid or out-of-order itemnos[] */
if (nextitm != nitems)
elog(ERROR, "incorrect index offsets supplied");
if (empty)
{
/* Page is completely empty, so just reset it quickly */
phdr->pd_lower = SizeOfPageHeaderData;
phdr->pd_upper = pd_special;
}
else
{
/* There are live items: need to compact the page the hard way */
itemIdSortData itemidbase[MaxOffsetNumber];
itemIdSort itemidptr;
int i;
Size totallen;
/*
* Scan the page taking note of each item that we need to preserve.
* This includes both live items (those that contain data) and
* interspersed unused ones. It's critical to preserve these unused
* items, because otherwise the offset numbers for later live items
* would change, which is not acceptable. Unused items might get used
* again later; that is fine.
*/
itemidptr = itemidbase;
totallen = 0;
PageClearHasFreeLinePointers(page);
for (i = 0; i < nline; i++)
{
ItemId lp;
itemidptr->offsetindex = i;
lp = PageGetItemId(page, i + 1);
if (ItemIdHasStorage(lp))
{
itemidptr->itemoff = ItemIdGetOffset(lp);
itemidptr->alignedlen = MAXALIGN(ItemIdGetLength(lp));
totallen += itemidptr->alignedlen;
itemidptr++;
}
else
{
PageSetHasFreeLinePointers(page);
ItemIdSetUnused(lp);
}
}
nline = itemidptr - itemidbase;
/* By here, there are exactly nline elements in itemidbase array */
if (totallen > (Size) (pd_special - pd_lower))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item lengths: total %u, available space %u",
(unsigned int) totallen, pd_special - pd_lower)));
/*
* Defragment the data areas of each tuple, being careful to preserve
* each item's position in the linp array.
*/
compactify_tuples(itemidbase, nline, page);
}
}
/*
* PageAddItem
*
* Add an item to a page. Return value is offset at which it was
* inserted, or InvalidOffsetNumber if there's not room to insert.
*
* If overwrite is true, we just store the item at the specified
* offsetNumber (which must be either a currently-unused item pointer,
* or one past the last existing item). Otherwise,
* if offsetNumber is valid and <= current max offset in the page,
* insert item into the array at that position by shuffling ItemId's
* down to make room.
* If offsetNumber is not valid, then assign one by finding the first
* one that is both unused and deallocated.
*
* If is_heap is true, we enforce that there can't be more than
* MaxHeapTuplesPerPage line pointers on the page.
*
* !!! EREPORT(ERROR) IS DISALLOWED HERE !!!
*/
OffsetNumber
PageAddItem(Page page,
Item item,
Size size,
OffsetNumber offsetNumber,
bool overwrite,
bool is_heap)
{
PageHeader phdr = (PageHeader) page;
Size alignedSize;
int lower;
int upper;
ItemId itemId;
OffsetNumber limit;
bool needshuffle = false;
/*
* Be wary about corrupted page pointers
*/
if (phdr->pd_lower < SizeOfPageHeaderData ||
phdr->pd_lower > phdr->pd_upper ||
phdr->pd_upper > phdr->pd_special ||
phdr->pd_special > BLCKSZ)
ereport(PANIC,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
phdr->pd_lower, phdr->pd_upper, phdr->pd_special)));
/*
* Select offsetNumber to place the new item at
*/
limit = OffsetNumberNext(PageGetMaxOffsetNumber(page));
/* was offsetNumber passed in? */
if (OffsetNumberIsValid(offsetNumber))
{
/* yes, check it */
if (overwrite)
{
if (offsetNumber < limit)
{
itemId = PageGetItemId(phdr, offsetNumber);
if (ItemIdIsUsed(itemId) || ItemIdHasStorage(itemId))
{
elog(WARNING, "will not overwrite a used ItemId");
return InvalidOffsetNumber;
}
}
}
else
{
if (offsetNumber < limit)
needshuffle = true; /* need to move existing linp's */
}
}
else
{
/* offsetNumber was not passed in, so find a free slot */
/* if no free slot, we'll put it at limit (1st open slot) */
if (PageHasFreeLinePointers(phdr))
{
/*
* Look for "recyclable" (unused) ItemId. We check for no storage
* as well, just to be paranoid --- unused items should never have
* storage.
*/
for (offsetNumber = 1; offsetNumber < limit; offsetNumber++)
{
itemId = PageGetItemId(phdr, offsetNumber);
if (!ItemIdIsUsed(itemId) && !ItemIdHasStorage(itemId))
break;
}
if (offsetNumber >= limit)
{
/* the hint is wrong, so reset it */
PageClearHasFreeLinePointers(phdr);
}
}
else
{
/* don't bother searching if hint says there's no free slot */
offsetNumber = limit;
}
}
if (offsetNumber > limit)
{
elog(WARNING, "specified item offset is too large");
return InvalidOffsetNumber;
}
if (is_heap && offsetNumber > MaxHeapTuplesPerPage)
{
elog(WARNING, "can't put more than MaxHeapTuplesPerPage items in a heap page");
return InvalidOffsetNumber;
}
/*
* Compute new lower and upper pointers for page, see if it'll fit.
*
* Note: do arithmetic as signed ints, to avoid mistakes if, say,
* alignedSize > pd_upper.
*/
if (offsetNumber == limit || needshuffle)
lower = phdr->pd_lower + sizeof(ItemIdData);
else
lower = phdr->pd_lower;
alignedSize = MAXALIGN(size);
upper = (int) phdr->pd_upper - (int) alignedSize;
if (lower > upper)
return InvalidOffsetNumber;
/*
* OK to insert the item. First, shuffle the existing pointers if needed.
*/
itemId = PageGetItemId(phdr, offsetNumber);
if (needshuffle)
memmove(itemId + 1, itemId,
(limit - offsetNumber) * sizeof(ItemIdData));
/* set the item pointer */
ItemIdSetNormal(itemId, upper, size);
/* copy the item's data onto the page */
memcpy((char *) page + upper, item, size);
/* adjust page header */
phdr->pd_lower = (LocationIndex) lower;
phdr->pd_upper = (LocationIndex) upper;
return offsetNumber;
}
/*
* PageRepairFragmentation
*
* Frees fragmented space on a page.
* It doesn't remove unused line pointers! Please don't change this.
*
* This routine is usable for heap pages only, but see PageIndexMultiDelete.
*
* Returns number of unused line pointers on page. If "unused" is not NULL
* then the unused[] array is filled with indexes of unused line pointers.
*/
int
PageRepairFragmentation(Page page, OffsetNumber *unused)
{
Offset pd_lower = ((PageHeader) page)->pd_lower;
Offset pd_upper = ((PageHeader) page)->pd_upper;
Offset pd_special = ((PageHeader) page)->pd_special;
itemIdSort itemidbase,
itemidptr;
ItemId lp;
int nline,
nused;
int i;
Size totallen;
Offset upper;
/*
* It's worth the trouble to be more paranoid here than in most places,
* because we are about to reshuffle data in (what is usually) a shared
* disk buffer. If we aren't careful then corrupted pointers, lengths,
* etc could cause us to clobber adjacent disk buffers, spreading the data
* loss further. So, check everything.
*/
if (pd_lower < SizeOfPageHeaderData ||
pd_lower > pd_upper ||
pd_upper > pd_special ||
pd_special > BLCKSZ ||
pd_special != MAXALIGN(pd_special))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted page pointers: lower = %u, upper = %u, special = %u",
pd_lower, pd_upper, pd_special),
errSendAlert(true)));
nline = PageGetMaxOffsetNumber(page);
nused = 0;
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
if (ItemIdDeleted(lp)) /* marked for deletion */
lp->lp_flags &= ~(LP_USED | LP_DELETE);
if (ItemIdIsUsed(lp))
nused++;
else if (unused)
unused[i - nused] = (OffsetNumber) i;
}
if (nused == 0)
{
/* Page is completely empty, so just reset it quickly */
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
lp->lp_len = 0; /* indicate unused & deallocated */
}
((PageHeader) page)->pd_upper = pd_special;
}
else
{ /* nused != 0 */
/* Need to compact the page the hard way */
itemidbase = (itemIdSort) palloc(sizeof(itemIdSortData) * nused);
itemidptr = itemidbase;
totallen = 0;
for (i = 0; i < nline; i++)
{
lp = PageGetItemId(page, i + 1);
if (ItemIdIsUsed(lp))
{
itemidptr->offsetindex = i;
itemidptr->itemoff = ItemIdGetOffset(lp);
if (itemidptr->itemoff < (int) pd_upper ||
itemidptr->itemoff >= (int) pd_special)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item pointer: %u",
itemidptr->itemoff),
errSendAlert(true)));
itemidptr->alignedlen = MAXALIGN(ItemIdGetLength(lp));
totallen += itemidptr->alignedlen;
itemidptr++;
}
else
{
lp->lp_len = 0; /* indicate unused & deallocated */
}
}
if (totallen > (Size) (pd_special - pd_lower))
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("corrupted item lengths: total %u, available space %u",
(unsigned int) totallen, pd_special - pd_lower),
errSendAlert(true)));
/* sort itemIdSortData array into decreasing itemoff order */
qsort((char *) itemidbase, nused, sizeof(itemIdSortData),
itemoffcompare);
/* compactify page */
upper = pd_special;
for (i = 0, itemidptr = itemidbase; i < nused; i++, itemidptr++)
{
lp = PageGetItemId(page, itemidptr->offsetindex + 1);
upper -= itemidptr->alignedlen;
memmove((char *) page + upper,
(char *) page + itemidptr->itemoff,
itemidptr->alignedlen);
lp->lp_off = upper;
}
((PageHeader) page)->pd_upper = upper;
pfree(itemidbase);
}
/* Set hint bit for PageAddItem */
if (nused < nline)
PageSetHasFreeLinePointers(page);
else
PageClearHasFreeLinePointers(page);
return (nline - nused);
}
uint16 addItemToPage(
void* page,
void* item,
size_t size,
uint16 itemnum,
Bool overwrite)
{
ItemPointer itemId;
PageHeader pageHdr = (PageHeader)page;
uint16 maxItemNum = RowsCountOnPage(page) + 1;
Bool needShuffle = False;
int num;
int newFreeStart, newFreeEnd;
size_t alignedSize;
if (IsItemIdValid(itemnum))
{
if (overwrite)
{
itemId = PageGetItemId(page, itemnum);
/* If the item is in use or has not empty storage
* we can not use it. Return 0.
*/
if (ItemIdIsInUse(itemId) || ItemIdHasStorage(itemId))
return 0;
}
else
{
/* If we are not overwriting an item
* and the offset number in less than max number
* Our page needs shuffle to free a room for the item.
*/
if (itemnum < maxItemNum)
needShuffle = True;
}
}
else
{
/* If itemnum is not passed in or is invalid,
* we need to find a free item. If there does not exist
* a free item, we will put it at the end of the page.
*/
if (PageHasFreeItems(pageHdr))
{
/* Look for unused items */
for (num = 1; num < maxItemNum; num++)
{
itemId = PageGetItemId(page, itemnum);
/* If the item is unused we break. */
if (!ItemIdIsInUse(itemId) && !ItemIdHasStorage(itemId))
break;
}
/* If we have reached the maximum offset, there are not free items. */
if (num >= maxItemNum)
{
/* the hint is wrong, so reset it */
PageClearHasFreeLinePointers(page);
}
}
else
{
/* If we have not a free item we try to insert it
* into the end of a page.
*/
itemnum = maxItemNum;
}
}
/* If we are inserting an item into the end or with a shuffle
* we need to insert an item into items array. We pull the free start
* right on one position.
*/
if (itemnum == maxItemNum || needShuffle)
newFreeStart = pageHdr->freeStart + sizeof(ItemPointerData);
else
newFreeStart = pageHdr->freeStart;
alignedSize = AlignDefault(size);
/* Calculate new free end. */
newFreeEnd = (int)pageHdr->freeEnd - (int)alignedSize;
/* if newFreeStart exceeds newFreeEnd we do not have
* a free room to put the item to
*/
if (newFreeStart > newFreeEnd)
return 0;
itemId = PageGetItemId(page, itemnum);
if (needShuffle)
memmove(itemId + 1, itemId,
(maxItemNum - itemnum) * sizeof(ItemPointerData));
itemId->flags = ITEM_NORMAL;
itemId->off = newFreeEnd;
itemId->len = size;
/* copy the item's data onto the page */
memcpy((char*)page + newFreeEnd, item, size);
/* Change free space range, freeStart and freeEnd. */
pageHdr->freeStart = (uint16)newFreeStart;
pageHdr->freeEnd = (uint16)newFreeEnd;
return itemnum;
}
