arrayfuncs.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 2,484 行 · 第 1/5 页

		return newarray;
	}

	if (nSubscripts <= 0 || nSubscripts > MAXDIM)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("wrong number of array subscripts")));

	/* make sure item to be inserted is not toasted */
	if (elmlen == -1 && !isNull)
		dataValue = PointerGetDatum(PG_DETOAST_DATUM(dataValue));

	/* detoast input array if necessary */
	array = DatumGetArrayTypeP(PointerGetDatum(array));

	ndim = ARR_NDIM(array);

	/*
	 * if number of dims is zero, i.e. an empty array, create an array with
	 * nSubscripts dimensions, and set the lower bounds to the supplied
	 * subscripts
	 */
	if (ndim == 0)
	{
		Oid			elmtype = ARR_ELEMTYPE(array);

		for (i = 0; i < nSubscripts; i++)
		{
			dim[i] = 1;
			lb[i] = indx[i];
		}

		return construct_md_array(&dataValue, &isNull, nSubscripts,
								  dim, lb, elmtype,
								  elmlen, elmbyval, elmalign);
	}

	if (ndim != nSubscripts)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("wrong number of array subscripts")));

	/* copy dim/lb since we may modify them */
	memcpy(dim, ARR_DIMS(array), ndim * sizeof(int));
	memcpy(lb, ARR_LBOUND(array), ndim * sizeof(int));

	newhasnulls = (ARR_HASNULL(array) || isNull);
	addedbefore = addedafter = 0;

	/*
	 * Check subscripts
	 */
	if (ndim == 1)
	{
		if (indx[0] < lb[0])
		{
			addedbefore = lb[0] - indx[0];
			dim[0] += addedbefore;
			lb[0] = indx[0];
			if (addedbefore > 1)
				newhasnulls = true;		/* will insert nulls */
		}
		if (indx[0] >= (dim[0] + lb[0]))
		{
			addedafter = indx[0] - (dim[0] + lb[0]) + 1;
			dim[0] += addedafter;
			if (addedafter > 1)
				newhasnulls = true;		/* will insert nulls */
		}
	}
	else
	{
		/*
		 * XXX currently we do not support extending multi-dimensional arrays
		 * during assignment
		 */
		for (i = 0; i < ndim; i++)
		{
			if (indx[i] < lb[i] ||
				indx[i] >= (dim[i] + lb[i]))
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("array subscript out of range")));
		}
	}

	/*
	 * Compute sizes of items and areas to copy
	 */
	newnitems = ArrayGetNItems(ndim, dim);
	if (newhasnulls)
		overheadlen = ARR_OVERHEAD_WITHNULLS(ndim, newnitems);
	else
		overheadlen = ARR_OVERHEAD_NONULLS(ndim);
	oldnitems = ArrayGetNItems(ndim, ARR_DIMS(array));
	oldnullbitmap = ARR_NULLBITMAP(array);
	oldoverheadlen = ARR_DATA_OFFSET(array);
	olddatasize = ARR_SIZE(array) - oldoverheadlen;
	if (addedbefore)
	{
		offset = 0;
		lenbefore = 0;
		olditemlen = 0;
		lenafter = olddatasize;
	}
	else if (addedafter)
	{
		offset = oldnitems;
		lenbefore = olddatasize;
		olditemlen = 0;
		lenafter = 0;
	}
	else
	{
		offset = ArrayGetOffset(nSubscripts, dim, lb, indx);
		elt_ptr = array_seek(ARR_DATA_PTR(array), 0, oldnullbitmap, offset,
							 elmlen, elmbyval, elmalign);
		lenbefore = (int) (elt_ptr - ARR_DATA_PTR(array));
		if (array_get_isnull(oldnullbitmap, offset))
			olditemlen = 0;
		else
		{
			olditemlen = att_addlength_pointer(0, elmlen, elt_ptr);
			olditemlen = att_align_nominal(olditemlen, elmalign);
		}
		lenafter = (int) (olddatasize - lenbefore - olditemlen);
	}

	if (isNull)
		newitemlen = 0;
	else
	{
		newitemlen = att_addlength_datum(0, elmlen, dataValue);
		newitemlen = att_align_nominal(newitemlen, elmalign);
	}

	newsize = overheadlen + lenbefore + newitemlen + lenafter;

	/*
	 * OK, create the new array and fill in header/dimensions
	 */
	newarray = (ArrayType *) palloc(newsize);
	SET_VARSIZE(newarray, newsize);
	newarray->ndim = ndim;
	newarray->dataoffset = newhasnulls ? overheadlen : 0;
	newarray->elemtype = ARR_ELEMTYPE(array);
	memcpy(ARR_DIMS(newarray), dim, ndim * sizeof(int));
	memcpy(ARR_LBOUND(newarray), lb, ndim * sizeof(int));

	/*
	 * Fill in data
	 */
	memcpy((char *) newarray + overheadlen,
		   (char *) array + oldoverheadlen,
		   lenbefore);
	if (!isNull)
		ArrayCastAndSet(dataValue, elmlen, elmbyval, elmalign,
						(char *) newarray + overheadlen + lenbefore);
	memcpy((char *) newarray + overheadlen + lenbefore + newitemlen,
		   (char *) array + oldoverheadlen + lenbefore + olditemlen,
		   lenafter);

	/*
	 * Fill in nulls bitmap if needed
	 *
	 * Note: it's possible we just replaced the last NULL with a non-NULL, and
	 * could get rid of the bitmap.  Seems not worth testing for though.
	 */
	if (newhasnulls)
	{
		bits8	   *newnullbitmap = ARR_NULLBITMAP(newarray);

		/* Zero the bitmap to take care of marking inserted positions null */
		MemSet(newnullbitmap, 0, (newnitems + 7) / 8);
		/* Fix the inserted value */
		if (addedafter)
			array_set_isnull(newnullbitmap, newnitems - 1, isNull);
		else
			array_set_isnull(newnullbitmap, offset, isNull);
		/* Fix the copied range(s) */
		if (addedbefore)
			array_bitmap_copy(newnullbitmap, addedbefore,
							  oldnullbitmap, 0,
							  oldnitems);
		else
		{
			array_bitmap_copy(newnullbitmap, 0,
							  oldnullbitmap, 0,
							  offset);
			if (addedafter == 0)
				array_bitmap_copy(newnullbitmap, offset + 1,
								  oldnullbitmap, offset + 1,
								  oldnitems - offset - 1);
		}
	}

	return newarray;
}

/*
 * array_set_slice :
 *		  This routine sets the value of a range of array locations (specified
 *		  by upper and lower subscript values) to new values passed as
 *		  another array.
 *
 * This handles both ordinary varlena arrays and fixed-length arrays.
 *
 * Inputs:
 *	array: the initial array object (mustn't be NULL)
 *	nSubscripts: number of subscripts supplied (must be same for upper/lower)
 *	upperIndx[]: the upper subscript values
 *	lowerIndx[]: the lower subscript values
 *	srcArray: the source for the inserted values
 *	isNull: indicates whether srcArray is NULL
 *	arraytyplen: pg_type.typlen for the array type
 *	elmlen: pg_type.typlen for the array's element type
 *	elmbyval: pg_type.typbyval for the array's element type
 *	elmalign: pg_type.typalign for the array's element type
 *
 * Result:
 *		  A new array is returned, just like the old except for the
 *		  modified range.  The original array object is not changed.
 *
 * For one-dimensional arrays only, we allow the array to be extended
 * by assigning to positions outside the existing subscript range; any
 * positions between the existing elements and the new ones are set to NULLs.
 * (XXX TODO: allow a corresponding behavior for multidimensional arrays)
 *
 * NOTE: we assume it is OK to scribble on the provided index arrays
 * lowerIndx[] and upperIndx[].  These are generally just temporaries.
 *
 * NOTE: For assignments, we throw an error for silly subscripts etc,
 * rather than returning a NULL or empty array as the fetch operations do.
 */
ArrayType *
array_set_slice(ArrayType *array,
				int nSubscripts,
				int *upperIndx,
				int *lowerIndx,
				ArrayType *srcArray,
				bool isNull,
				int arraytyplen,
				int elmlen,
				bool elmbyval,
				char elmalign)
{
	ArrayType  *newarray;
	int			i,
				ndim,
				dim[MAXDIM],
				lb[MAXDIM],
				span[MAXDIM];
	bool		newhasnulls;
	int			nitems,
				nsrcitems,
				olddatasize,
				newsize,
				olditemsize,
				newitemsize,
				overheadlen,
				oldoverheadlen,
				addedbefore,
				addedafter,
				lenbefore,
				lenafter,
				itemsbefore,
				itemsafter,
				nolditems;

	/* Currently, assignment from a NULL source array is a no-op */
	if (isNull)
		return array;

	if (arraytyplen > 0)
	{
		/*
		 * fixed-length arrays -- not got round to doing this...
		 */
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
		errmsg("updates on slices of fixed-length arrays not implemented")));
	}

	/* detoast arrays if necessary */
	array = DatumGetArrayTypeP(PointerGetDatum(array));
	srcArray = DatumGetArrayTypeP(PointerGetDatum(srcArray));

	/* note: we assume srcArray contains no toasted elements */

	ndim = ARR_NDIM(array);

	/*
	 * if number of dims is zero, i.e. an empty array, create an array with
	 * nSubscripts dimensions, and set the upper and lower bounds to the
	 * supplied subscripts
	 */
	if (ndim == 0)
	{
		Datum	   *dvalues;
		bool	   *dnulls;
		int			nelems;
		Oid			elmtype = ARR_ELEMTYPE(array);

		deconstruct_array(srcArray, elmtype, elmlen, elmbyval, elmalign,
						  &dvalues, &dnulls, &nelems);

		for (i = 0; i < nSubscripts; i++)
		{
			dim[i] = 1 + upperIndx[i] - lowerIndx[i];
			lb[i] = lowerIndx[i];
		}

		/* complain if too few source items; we ignore extras, however */
		if (nelems < ArrayGetNItems(nSubscripts, dim))
			ereport(ERROR,
					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("source array too small")));

		return construct_md_array(dvalues, dnulls, nSubscripts,
								  dim, lb, elmtype,
								  elmlen, elmbyval, elmalign);
	}

	if (ndim < nSubscripts || ndim <= 0 || ndim > MAXDIM)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("wrong number of array subscripts")));

	/* copy dim/lb since we may modify them */
	memcpy(dim, ARR_DIMS(array), ndim * sizeof(int));
	memcpy(lb, ARR_LBOUND(array), ndim * sizeof(int));

	newhasnulls = (ARR_HASNULL(array) || ARR_HASNULL(srcArray));
	addedbefore = addedafter = 0;

	/*
	 * Check subscripts
	 */
	if (ndim == 1)
	{
		Assert(nSubscripts == 1);
		if (lowerIndx[0] > upperIndx[0])
			ereport(ERROR,
					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("upper bound cannot be less than lower bound")));
		if (lowerIndx[0] < lb[0])
		{
			if (upperIndx[0] < lb[0] - 1)
				newhasnulls = true;		/* will insert nulls */
			addedbefore = lb[0] - lowerIndx[0];
			dim[0] += addedbefore;
			lb[0] = lowerIndx[0];
		}
		if (upperIndx[0] >= (dim[0] + lb[0]))
		{
			if (lowerIndx[0] > (dim[0] + lb[0]))
				newhasnulls = true;		/* will insert nulls */
			addedafter = upperIndx[0] - (dim[0] + lb[0]) + 1;
			dim[0] += addedafter;
		}
	}
	else
	{
		/*
		 * XXX currently we do not support extending multi-dimensional arrays
		 * during assignment
		 */
		for (i = 0; i < nSubscripts; i++)
		{
			if (lowerIndx[i] > upperIndx[i])
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("upper bound cannot be less than lower bound")));
			if (lowerIndx[i] < lb[i] ||
				upperIndx[i] >= (dim[i] + lb[i]))
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("array subscript out of range")));
		}
		/* fill any missing subscript positions with full array range */
		for (; i < ndim; i++)
		{
			lowerIndx[i] = lb[i];
			upperIndx[i] = dim[i] + lb[i] - 1;
			if (lowerIndx[i] > upperIndx[i])
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("upper bound cannot be less than lower bound")));
		}
	}

	/* Do this mainly to check for overflow */
	nitems = ArrayGetNItems(ndim, dim);

	/*
	 * Make sure source array has enough entries.  Note we ignore the shape of
	 * the source array and just read entries serially.
	 */
	mda_get_range(ndim, span, lowerIndx, upperIndx);
	nsrcitems = ArrayGetNItems(ndim, span);
	if (nsrcitems > ArrayGetNItems(ARR_NDIM(srcArray), ARR_DIMS(srcArray)))
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("source array too small")));

	/*
	 * Compute space occupied by new entries, space occupied by replaced
	 * entries, and required space for new array.
	 */
	if (newhasnulls)
		overheadlen = ARR_OVERHEAD_WITHNULLS(ndim, nitems);
	else
		overheadlen = ARR_OVERHEAD_NONULLS(ndim);
	newitemsize = array_nelems_size(ARR_DATA_PTR(srcArray), 0,
									ARR_NULLBITMAP(srcArray), nsrcitems,
									elmlen, elmbyval, elmalign);
	oldoverheadlen = ARR_DATA_OFFSET(array);
	olddatasize = ARR_SIZE(array) - oldoverheadlen;
	if (ndim > 1)
	{
		/*
		 * here we do not need to cope with extension of the array; it would
		 * be a lot more complicated if we had to do so...
		 */
		olditemsize = array_slice_size(ARR_DATA_PTR(array),
									   ARR_NULLBITMAP(array),
									   ndim, dim, lb,
									   lowerIndx, upperIndx,
									   elmlen, elmbyval, elmalign);
		lenbefore = lenafter = 0;		/* keep compiler quiet */
		itemsbefore = itemsafter = nolditems = 0;
	}
	else
	{
		/*
		 * here we must allow for possibility of slice larger than orig array
		 */
		int			oldlb = ARR_LBOUND(array)[0];
		int			oldub = oldlb + ARR_DIMS(array)[0] - 1;
		int			slicelb = Max(oldlb, lowerIndx[0]);
		int			sliceub = Min(oldub, upperIndx[0]);
		char	   *oldarraydata = ARR_DATA_PTR(array);
		bits8	   *oldarraybitmap = ARR_NULLBITMAP(array);

		itemsbefore = Min(slicelb, oldub + 1) - oldlb;
		lenbefore = array_nelems_size(oldarraydata, 0, oldarraybitmap,
									  itemsbefore,
									  elmlen, elmbyval, elmalign);
		if (slicelb > sliceub)
		{
			nolditems = 0;
			olditemsize = 0;
		}
		else
		{
			nolditems = sliceub - slicelb + 1;
			olditemsize = array_nelems_size(oldarraydata + lenbefore,
											itemsbefore, oldarraybitmap,
											nolditems,
											elmlen, elmbyval, elmalign);
		}
		itemsafter = oldub - sliceub;
		lenafter = olddatasize - lenbefore - olditemsize;
	}

	newsize = overheadlen + olddatasize - olditemsize + newitemsize;

	newarray = (ArrayType *) palloc(newsize);
	SET_VARSIZE(newarray, newsize);
	newarray->ndim = ndim;
	newarray->dataoffset = newhasnulls ? overheadlen : 0;
	newarray->elemtype = ARR_ELEMTYPE(array);
	memcpy(ARR_DIMS(newarray), dim, ndim * sizeof(int));
	memcpy(ARR_LBOUND(newarray), lb, ndim * sizeof(int));

	if (ndim > 1)
	{
		/*
		 * here we do not need to cope with extension of the array; it would
		 * be a lot more complicated if we had to do so...
		 */
		array_insert_slice(newarray, array, srcArray,
						   ndim, dim, lb,
						   lowerIndx, upperIndx,
						   elmlen, elmbyval, elmalign);
	}
	else
	{
		/* fill in data */
		memcpy((char *) newarray + overheadlen,
			   (char *) array + oldoverheadlen,
			   lenbefore);
		memcpy((char *) newarray + overheadlen + lenbefore,
			   ARR_DATA_PTR(srcArray),
			   newitemsize);
		memcpy((char *) newarr