*** pgsql/src/backend/utils/adt/arrayfuncs.c	2008/11/12 13:09:27	1.149
--- pgsql/src/backend/utils/adt/arrayfuncs.c	2008/11/14 00:51:46	1.150
***************
*** 8,14 ****
   *
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.148 2008/11/04 14:49:11 petere Exp $
   *
   *-------------------------------------------------------------------------
   */
--- 8,14 ----
   *
   *
   * IDENTIFICATION
!  *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.149 2008/11/12 13:09:27 petere Exp $
   *
   *-------------------------------------------------------------------------
   */
*************** array_fill_internal(ArrayType *dims, Arr
*** 4635,4637 ****
--- 4635,4741 ----
  
  	return result;
  }
+ 
+ 
+ /*
+  * UNNEST
+  */
+ Datum
+ array_unnest(PG_FUNCTION_ARGS)
+ {
+ 	typedef struct
+ 	{
+ 		ArrayType *arr;
+ 		int		nextelem;
+ 		int		numelems;
+ 		char   *elemdataptr;	/* this moves with nextelem */
+ 		bits8  *arraynullsptr;	/* this does not */
+ 		int16	elmlen;
+ 		bool	elmbyval;
+ 		char	elmalign;
+ 	} array_unnest_fctx;
+ 
+ 	FuncCallContext *funcctx;
+ 	array_unnest_fctx *fctx;
+ 	MemoryContext oldcontext;
+ 
+ 	/* stuff done only on the first call of the function */
+ 	if (SRF_IS_FIRSTCALL())
+ 	{
+ 		ArrayType  *arr = PG_GETARG_ARRAYTYPE_P(0);
+ 
+ 		/* create a function context for cross-call persistence */
+ 		funcctx = SRF_FIRSTCALL_INIT();
+ 
+ 		/*
+ 		 * switch to memory context appropriate for multiple function calls
+ 		 */
+ 		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+ 
+ 		/* allocate memory for user context */
+ 		fctx = (array_unnest_fctx *) palloc(sizeof(array_unnest_fctx));
+ 
+ 		/*
+ 		 * Initialize state.  Note we assume that the originally passed
+ 		 * array will stick around for the whole call series.
+ 		 */
+ 		fctx->arr = arr;
+ 		fctx->nextelem = 0;
+ 		fctx->numelems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
+ 
+ 		fctx->elemdataptr = ARR_DATA_PTR(arr);
+ 		fctx->arraynullsptr = ARR_NULLBITMAP(arr);
+ 
+ 		get_typlenbyvalalign(ARR_ELEMTYPE(arr),
+ 							 &fctx->elmlen,
+ 							 &fctx->elmbyval,
+ 							 &fctx->elmalign);
+ 
+ 		funcctx->user_fctx = fctx;
+ 		MemoryContextSwitchTo(oldcontext);
+ 	}
+ 
+ 	/* stuff done on every call of the function */
+ 	funcctx = SRF_PERCALL_SETUP();
+ 	fctx = funcctx->user_fctx;
+ 
+ 	if (fctx->nextelem < fctx->numelems)
+ 	{
+ 		int		offset = fctx->nextelem++;
+ 		Datum	elem;
+ 
+ 		/*
+ 		 * Check for NULL array element
+ 		 */
+ 		if (array_get_isnull(fctx->arraynullsptr, offset))
+ 		{
+ 			fcinfo->isnull = true;
+ 			elem = (Datum) 0;
+ 			/* elemdataptr does not move */
+ 		}
+ 		else
+ 		{
+ 			/*
+ 			 * OK, get the element
+ 			 */
+ 			char   *ptr = fctx->elemdataptr;
+ 
+ 			fcinfo->isnull = false;
+ 			elem = ArrayCast(ptr, fctx->elmbyval, fctx->elmlen);
+ 
+ 			/*
+ 			 * Advance elemdataptr over it
+ 			 */
+ 			ptr = att_addlength_pointer(ptr, fctx->elmlen, ptr);
+ 			ptr = (char *) att_align_nominal(ptr, fctx->elmalign);
+ 			fctx->elemdataptr = ptr;
+ 		}
+ 
+ 		SRF_RETURN_NEXT(funcctx, elem);
+ 	}
+ 	else
+ 	{
+ 		/* do when there is no more left */
+ 		SRF_RETURN_DONE(funcctx);
+ 	}
+ }