/*
* Manage the allocation state of the array
*
* Note that the array needs to be in a reasonably long-lived context,
* ie the Agg node's aggcontext.
*/
static PGARRAY *
GetPGArray(PGARRAY * p, AggState *aggstate, bool fAdd)
{
if (!p)
{
/* New array */
int cb = PGARRAY_SIZE(START_NUM);
p = (PGARRAY *) MemoryContextAlloc(aggstate->aggcontext, cb);
p->a.size = cb;
p->a.ndim = 1;
p->a.flags = 0;
p->a.elemtype = INT4OID;
p->items = 0;
p->lower = START_NUM;
}
else if (fAdd)
{
/* Ensure array has space for another item */
if (p->items >= p->lower)
{
PGARRAY *pn;
int n = p->lower * 2;
int cbNew = PGARRAY_SIZE(n);
pn = (PGARRAY *) MemoryContextAlloc(aggstate->aggcontext, cbNew);
memcpy(pn, p, p->a.size);
pn->a.size = cbNew;
pn->lower = n;
/* do not pfree(p), because nodeAgg.c will */
p = pn;
}
}
return p;
}
/*
* Manage the aggregation state of the array
*
* Need to specify a suitably long-lived memory context, or it will vanish!
* PortalContext isn't really right, but it's close enough.
*/
static PGARRAY *
GetPGArray(PGARRAY *p, int fAdd)
{
if (!p)
{
/* New array */
int cb = PGARRAY_SIZE(START_NUM);
p = (PGARRAY *) MemoryContextAlloc(PortalContext, cb);
p->a.size = cb;
p->a.ndim = 0;
p->a.flags = 0;
p->a.elemtype = INT4OID;
p->items = 0;
p->lower = START_NUM;
}
else if (fAdd)
{ /* Ensure array has space */
if (p->items >= p->lower)
{
PGARRAY *pn;
int n = p->lower + p->lower;
int cbNew = PGARRAY_SIZE(n);
pn = (PGARRAY *) repalloc(p, cbNew);
pn->a.size = cbNew;
pn->lower = n;
return pn;
}
}
return p;
}
/* Shrinks the array to its actual size and moves it into the standard
* memory allocation context, frees working memory
*/
static PGARRAY *
ShrinkPGArray(PGARRAY * p)
{
PGARRAY *pnew = NULL;
if (p)
{
/* get target size */
int cb = PGARRAY_SIZE(p->items);
/* use current transaction context */
pnew = palloc(cb);
/*
* Fix up the fields in the new structure, so Postgres understands
*/
memcpy(pnew, p, cb);
pnew->a.size = cb;
pnew->a.ndim = 1;
pnew->a.flags = 0;
pnew->a.elemtype = INT4OID;
pnew->lower = 1;
pfree(p);
}
return pnew;
}
/*
* Shrinks the array to its actual size and moves it into the standard
* memory allocation context
*/
static PGARRAY *
ShrinkPGArray(PGARRAY * p)
{
PGARRAY *pnew;
/* get target size */
int cb = PGARRAY_SIZE(p->items);
/* use current transaction context */
pnew = palloc(cb);
memcpy(pnew, p, cb);
/* fix up the fields in the new array to match normal conventions */
pnew->a.size = cb;
pnew->lower = 1;
/* do not pfree(p), because nodeAgg.c will */
return pnew;
}
