Function array_in

src/backend/utils/adt/arrayfuncs.c:176–428

* array_in : * converts an array from the external format in "string" to * its internal format. * * return value : * the internal representation of the input array */

 *		  the internal representation of the input array
 */
Datum
array_in(PG_FUNCTION_ARGS)
{
	char	   *string = PG_GETARG_CSTRING(0);	/* external form */
	Oid			element_type = PG_GETARG_OID(1);	/* type of an array
													 * element */
	int32		typmod = PG_GETARG_INT32(2);	/* typmod for array elements */
	int			typlen;
	bool		typbyval;
	char		typalign;
	char		typdelim;
	Oid			typioparam;
	char	   *string_save,
			   *p;
	int			i,
				nitems;
	Datum	   *dataPtr;
	bool	   *nullsPtr;
	bool		hasnulls;
	int32		nbytes;
	int32		dataoffset;
	ArrayType  *retval;
	int			ndim,
				dim[MAXDIM],
				lBound[MAXDIM];
	ArrayMetaState *my_extra;

	/*
	 * We arrange to look up info about element type, including its input
	 * conversion proc, only once per series of calls, assuming the element
	 * type doesn't change underneath us.
	 */
	my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
	if (my_extra == NULL)
	{
		fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
													  sizeof(ArrayMetaState));
		my_extra = (ArrayMetaState *) fcinfo->flinfo->fn_extra;
		my_extra->element_type = ~element_type;
	}

	if (my_extra->element_type != element_type)
	{
		/*
		 * Get info about element type, including its input conversion proc
		 */
		get_type_io_data(element_type, IOFunc_input,
						 &my_extra->typlen, &my_extra->typbyval,
						 &my_extra->typalign, &my_extra->typdelim,
						 &my_extra->typioparam, &my_extra->typiofunc);
		fmgr_info_cxt(my_extra->typiofunc, &my_extra->proc,
					  fcinfo->flinfo->fn_mcxt);
		my_extra->element_type = element_type;
	}
	typlen = my_extra->typlen;
	typbyval = my_extra->typbyval;
	typalign = my_extra->typalign;
	typdelim = my_extra->typdelim;