/*-----------------------------------------------------------------------------
* array_prepend :
* push an element onto the front of a one-dimensional array
*----------------------------------------------------------------------------
*/
Datum
array_prepend(PG_FUNCTION_ARGS)
{
ExpandedArrayHeader *eah;
Datum newelem;
bool isNull;
Datum result;
int *lb;
int indx;
int lb0;
ArrayMetaState *my_extra;
isNull = PG_ARGISNULL(0);
if (isNull)
newelem = (Datum) 0;
else
newelem = PG_GETARG_DATUM(0);
eah = fetch_array_arg_replace_nulls(fcinfo, 1);
if (eah->ndims == 1)
{
/* prepend newelem */
lb = eah->lbound;
indx = lb[0] - 1;
lb0 = lb[0];
/* overflow? */
if (indx > lb[0])
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("integer out of range")));
}
else if (eah->ndims == 0)
{
indx = 1;
lb0 = 1;
}
else
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("argument must be empty or one-dimensional array")));
/* Perform element insertion */
my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
result = array_set_element(EOHPGetRWDatum(&eah->hdr),
1, &indx, newelem, isNull,
-1, my_extra->typlen, my_extra->typbyval, my_extra->typalign);
/* Readjust result's LB to match the input's, as expected for prepend */
Assert(result == EOHPGetRWDatum(&eah->hdr));
if (eah->ndims == 1)
{
/* This is ok whether we've deconstructed or not */
eah->lbound[0] = lb0;
}
PG_RETURN_DATUM(result);
}
/*-----------------------------------------------------------------------------
* array_append :
* push an element onto the end of a one-dimensional array
*----------------------------------------------------------------------------
*/
Datum
array_append(PG_FUNCTION_ARGS)
{
ExpandedArrayHeader *eah;
Datum newelem;
bool isNull;
Datum result;
int *dimv,
*lb;
int indx;
ArrayMetaState *my_extra;
eah = fetch_array_arg_replace_nulls(fcinfo, 0);
isNull = PG_ARGISNULL(1);
if (isNull)
newelem = (Datum) 0;
else
newelem = PG_GETARG_DATUM(1);
if (eah->ndims == 1)
{
/* append newelem */
int ub;
lb = eah->lbound;
dimv = eah->dims;
ub = dimv[0] + lb[0] - 1;
indx = ub + 1;
/* overflow? */
if (indx < ub)
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("integer out of range")));
}
else if (eah->ndims == 0)
indx = 1;
else
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("argument must be empty or one-dimensional array")));
/* Perform element insertion */
my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
result = array_set_element(EOHPGetRWDatum(&eah->hdr),
1, &indx, newelem, isNull,
-1, my_extra->typlen, my_extra->typbyval, my_extra->typalign);
PG_RETURN_DATUM(result);
}
/*
* Transfer ownership of an expanded object to a new___ parent memory context.
* The object must be referenced by a R/W pointer, and what we return is
* always its "standard" R/W pointer, which is certain to have the same
* lifespan as the object itself. (The passed-in pointer might not, and
* in any case wouldn't provide a unique identifier if it's not that one.)
*/
Datum
TransferExpandedObject(Datum d, MemoryContext new_parent)
{
ExpandedObjectHeader *eohptr = DatumGetEOHP(d);
/* Assert caller gave a R/W pointer */
Assert(VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(d)));
/* Transfer ownership */
MemoryContextSetParent(eohptr->eoh_context, new_parent);
/* Return the object's standard read-write pointer */
return EOHPGetRWDatum(eohptr);
}
/*
* expand_array: convert an array Datum into an expanded array
*
* The expanded object will be a child of parentcontext.
*
* Some callers can provide cache space to avoid repeated lookups of element
* type data across calls; if so, pass a metacache pointer, making sure that
* metacache->element_type is initialized to InvalidOid before first call.
* If no cross-call caching is required, pass NULL for metacache.
*/
Datum
expand_array(Datum arraydatum, MemoryContext parentcontext,
ArrayMetaState *metacache)
{
ArrayType *array;
ExpandedArrayHeader *eah;
MemoryContext objcxt;
MemoryContext oldcxt;
ArrayMetaState fakecache;
/*
* Allocate private context for expanded object. We start by assuming
* that the array won't be very large; but if it does grow a lot, don't
* constrain aset.c's large-context behavior.
*/
objcxt = AllocSetContextCreate(parentcontext,
"expanded array",
ALLOCSET_START_SMALL_SIZES);
/* Set up expanded array header */
eah = (ExpandedArrayHeader *)
MemoryContextAlloc(objcxt, sizeof(ExpandedArrayHeader));
EOH_init_header(&eah->hdr, &EA_methods, objcxt);
eah->ea_magic = EA_MAGIC;
/* If the source is an expanded array, we may be able to optimize */
if (VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(arraydatum)))
{
ExpandedArrayHeader *oldeah = (ExpandedArrayHeader *) DatumGetEOHP(arraydatum);
Assert(oldeah->ea_magic == EA_MAGIC);
/*
* Update caller's cache if provided; we don't need it this time, but
* next call might be for a non-expanded source array. Furthermore,
* if the caller didn't provide a cache area, use some local storage
* to cache anyway, thereby avoiding a catalog lookup in the case
* where we fall through to the flat-copy code path.
*/
if (metacache == NULL)
metacache = &fakecache;
metacache->element_type = oldeah->element_type;
metacache->typlen = oldeah->typlen;
metacache->typbyval = oldeah->typbyval;
metacache->typalign = oldeah->typalign;
/*
* If element type is pass-by-value and we have a Datum-array
* representation, just copy the source's metadata and Datum/isnull
* arrays. The original flat array, if present at all, adds no
* additional information so we need not copy it.
*/
if (oldeah->typbyval && oldeah->dvalues != NULL)
{
copy_byval_expanded_array(eah, oldeah);
/* return a R/W pointer to the expanded array */
return EOHPGetRWDatum(&eah->hdr);
}
/*
* Otherwise, either we have only a flat representation or the
* elements are pass-by-reference. In either case, the best thing
* seems to be to copy the source as a flat representation and then
* deconstruct that later if necessary. For the pass-by-ref case, we
* could perhaps save some cycles with custom code that generates the
* deconstructed representation in parallel with copying the values,
* but it would be a lot of extra code for fairly marginal gain. So,
* fall through into the flat-source code path.
*/
}
/*
* Detoast and copy source array into private context, as a flat array.
*
* Note that this coding risks leaking some memory in the private context
* if we have to fetch data from a TOAST table; however, experimentation
* says that the leak is minimal. Doing it this way saves a copy step,
* which seems worthwhile, especially if the array is large enough to need
* external storage.
*/
oldcxt = MemoryContextSwitchTo(objcxt);
array = DatumGetArrayTypePCopy(arraydatum);
MemoryContextSwitchTo(oldcxt);
eah->ndims = ARR_NDIM(array);
/* note these pointers point into the fvalue header! */
eah->dims = ARR_DIMS(array);
eah->lbound = ARR_LBOUND(array);
/* Save array's element-type data for possible use later */
eah->element_type = ARR_ELEMTYPE(array);
if (metacache && metacache->element_type == eah->element_type)
{
/* We have a valid cache of representational data */
eah->typlen = metacache->typlen;
eah->typbyval = metacache->typbyval;
eah->typalign = metacache->typalign;
}
else
{
/* No, so look it up */
get_typlenbyvalalign(eah->element_type,
&eah->typlen,
&eah->typbyval,
&eah->typalign);
/* Update cache if provided */
if (metacache)
{
metacache->element_type = eah->element_type;
metacache->typlen = eah->typlen;
metacache->typbyval = eah->typbyval;
metacache->typalign = eah->typalign;
}
}
/* we don't make a deconstructed representation now */
eah->dvalues = NULL;
eah->dnulls = NULL;
eah->dvalueslen = 0;
eah->nelems = 0;
eah->flat_size = 0;
/* remember we have a flat representation */
eah->fvalue = array;
eah->fstartptr = ARR_DATA_PTR(array);
eah->fendptr = ((char *) array) + ARR_SIZE(array);
/* return a R/W pointer to the expanded array */
return EOHPGetRWDatum(&eah->hdr);
}