arrayfuncs.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,367 行 · 第 1/5 页

	 * OK, get the element
	 */
	offset = ArrayGetOffset(nSubscripts, dim, lb, indx);

	retptr = array_seek(arraydataptr, offset, elmlen, elmbyval, elmalign);

	*isNull = false;
	return ArrayCast(retptr, elmbyval, elmlen);
}

/*-----------------------------------------------------------------------------
 * array_get_slice :
 *		   This routine takes an array and a range of indices (upperIndex and
 *		   lowerIndx), creates a new array structure for the referred elements
 *		   and returns a pointer to it.
 *
 * NOTE: we assume it is OK to scribble on the provided index arrays
 * lowerIndx[] and upperIndx[].  These are generally just temporaries.
 *-----------------------------------------------------------------------------
 */
ArrayType *
array_get_slice(ArrayType *array,
				int nSubscripts,
				int *upperIndx,
				int *lowerIndx,
				int arraylen,
				int elmlen,
				bool elmbyval,
				char elmalign,
				bool *isNull)
{
	int			i,
				ndim,
			   *dim,
			   *lb,
			   *newlb;
	int			fixedDim[1],
				fixedLb[1];
	char	   *arraydataptr;
	ArrayType  *newarray;
	int			bytes,
				span[MAXDIM];

	if (array == (ArrayType *) NULL)
		RETURN_NULL(ArrayType *);

	if (arraylen > 0)
	{
		/*
		 * fixed-length arrays -- currently, cannot slice these because
		 * parser labels output as being of the fixed-length array type!
		 * Code below shows how we could support it if the parser were
		 * changed to label output as a suitable varlena array type.
		 */
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			   errmsg("slices of fixed-length arrays not implemented")));

		/*
		 * fixed-length arrays -- these are assumed to be 1-d, 0-based XXX
		 * where would we get the correct ELEMTYPE from?
		 */
		ndim = 1;
		fixedDim[0] = arraylen / elmlen;
		fixedLb[0] = 0;
		dim = fixedDim;
		lb = fixedLb;
		arraydataptr = (char *) array;
	}
	else
	{
		/* detoast input array if necessary */
		array = DatumGetArrayTypeP(PointerGetDatum(array));

		ndim = ARR_NDIM(array);
		dim = ARR_DIMS(array);
		lb = ARR_LBOUND(array);
		arraydataptr = ARR_DATA_PTR(array);
	}

	/*
	 * Check provided subscripts.  A slice exceeding the current array
	 * limits is silently truncated to the array limits.  If we end up
	 * with an empty slice, return NULL (should it be an empty array
	 * instead?)
	 */
	if (ndim < nSubscripts || ndim <= 0 || ndim > MAXDIM)
		RETURN_NULL(ArrayType *);

	for (i = 0; i < nSubscripts; i++)
	{
		if (lowerIndx[i] < lb[i])
			lowerIndx[i] = lb[i];
		if (upperIndx[i] >= (dim[i] + lb[i]))
			upperIndx[i] = dim[i] + lb[i] - 1;
		if (lowerIndx[i] > upperIndx[i])
			RETURN_NULL(ArrayType *);
	}
	/* 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])
			RETURN_NULL(ArrayType *);
	}

	mda_get_range(ndim, span, lowerIndx, upperIndx);

	bytes = array_slice_size(ndim, dim, lb, arraydataptr,
							 lowerIndx, upperIndx,
							 elmlen, elmbyval, elmalign);
	bytes += ARR_OVERHEAD(ndim);

	newarray = (ArrayType *) palloc(bytes);
	newarray->size = bytes;
	newarray->ndim = ndim;
	newarray->flags = 0;
	newarray->elemtype = ARR_ELEMTYPE(array);
	memcpy(ARR_DIMS(newarray), span, ndim * sizeof(int));

	/*
	 * Lower bounds of the new array are set to 1.	Formerly (before 7.3)
	 * we copied the given lowerIndx values ... but that seems confusing.
	 */
	newlb = ARR_LBOUND(newarray);
	for (i = 0; i < ndim; i++)
		newlb[i] = 1;

	array_extract_slice(ndim, dim, lb, arraydataptr,
						lowerIndx, upperIndx, ARR_DATA_PTR(newarray),
						elmlen, elmbyval, elmalign);

	return newarray;
}

/*-----------------------------------------------------------------------------
 * array_set :
 *		  This routine sets the value of an array location (specified by
 *		  an index array) to a new value specified by "dataValue".
 * result :
 *		  A new array is returned, just like the old except for the one
 *		  modified entry.
 *
 * For one-dimensional arrays only, we allow the array to be extended
 * by assigning to the position one above or one below the existing range.
 * (We could be more flexible if we had a way to represent NULL elements.)
 *
 * NOTE: For assignments, we throw an error for invalid subscripts etc,
 * rather than returning a NULL as the fetch operations do.  The reasoning
 * is that returning a NULL would cause the user's whole array to be replaced
 * with NULL, which will probably not make him happy.
 *-----------------------------------------------------------------------------
 */
ArrayType *
array_set(ArrayType *array,
		  int nSubscripts,
		  int *indx,
		  Datum dataValue,
		  int arraylen,
		  int elmlen,
		  bool elmbyval,
		  char elmalign,
		  bool *isNull)
{
	int			i,
				ndim,
				dim[MAXDIM],
				lb[MAXDIM],
				offset;
	ArrayType  *newarray;
	char	   *elt_ptr;
	bool		extendbefore = false;
	bool		extendafter = false;
	int			olddatasize,
				newsize,
				olditemlen,
				newitemlen,
				overheadlen,
				lenbefore,
				lenafter;

	if (array == (ArrayType *) NULL)
		RETURN_NULL(ArrayType *);

	if (arraylen > 0)
	{
		/*
		 * fixed-length arrays -- these are assumed to be 1-d, 0-based. We
		 * cannot extend them, either.
		 */
		if (nSubscripts != 1)
			ereport(ERROR,
					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("invalid array subscripts")));

		if (indx[0] < 0 || indx[0] * elmlen >= arraylen)
			ereport(ERROR,
					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("invalid array subscripts")));

		newarray = (ArrayType *) palloc(arraylen);
		memcpy(newarray, array, arraylen);
		elt_ptr = (char *) newarray + indx[0] * elmlen;
		ArrayCastAndSet(dataValue, elmlen, elmbyval, elmalign, elt_ptr);
		return newarray;
	}

	/* make sure item to be inserted is not toasted */
	if (elmlen == -1)
		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, nSubscripts, dim, lb, elmtype,
								  elmlen, elmbyval, elmalign);
	}

	if (ndim != nSubscripts || ndim <= 0 || ndim > MAXDIM)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("invalid 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));

	/*
	 * Check subscripts
	 */
	for (i = 0; i < ndim; i++)
	{
		if (indx[i] < lb[i])
		{
			if (ndim == 1 && indx[i] == lb[i] - 1)
			{
				dim[i]++;
				lb[i]--;
				extendbefore = true;
			}
			else
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("invalid array subscripts")));
		}
		if (indx[i] >= (dim[i] + lb[i]))
		{
			if (ndim == 1 && indx[i] == (dim[i] + lb[i]))
			{
				dim[i]++;
				extendafter = true;
			}
			else
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("invalid array subscripts")));
		}
	}

	/*
	 * Compute sizes of items and areas to copy
	 */
	overheadlen = ARR_OVERHEAD(ndim);
	olddatasize = ARR_SIZE(array) - overheadlen;
	if (extendbefore)
	{
		lenbefore = 0;
		olditemlen = 0;
		lenafter = olddatasize;
	}
	else if (extendafter)
	{
		lenbefore = olddatasize;
		olditemlen = 0;
		lenafter = 0;
	}
	else
	{
		offset = ArrayGetOffset(nSubscripts, dim, lb, indx);
		elt_ptr = array_seek(ARR_DATA_PTR(array), offset,
							 elmlen, elmbyval, elmalign);
		lenbefore = (int) (elt_ptr - ARR_DATA_PTR(array));
		olditemlen = att_addlength(0, elmlen, PointerGetDatum(elt_ptr));
		olditemlen = att_align(olditemlen, elmalign);
		lenafter = (int) (olddatasize - lenbefore - olditemlen);
	}

	newitemlen = att_addlength(0, elmlen, dataValue);
	newitemlen = att_align(newitemlen, elmalign);

	newsize = overheadlen + lenbefore + newitemlen + lenafter;

	/*
	 * OK, do the assignment
	 */
	newarray = (ArrayType *) palloc(newsize);
	newarray->size = newsize;
	newarray->ndim = ndim;
	newarray->flags = 0;
	newarray->elemtype = ARR_ELEMTYPE(array);
	memcpy(ARR_DIMS(newarray), dim, ndim * sizeof(int));
	memcpy(ARR_LBOUND(newarray), lb, ndim * sizeof(int));
	memcpy((char *) newarray + overheadlen,
		   (char *) array + overheadlen,
		   lenbefore);
	memcpy((char *) newarray + overheadlen + lenbefore + newitemlen,
		   (char *) array + overheadlen + lenbefore + olditemlen,
		   lenafter);

	ArrayCastAndSet(dataValue, elmlen, elmbyval, elmalign,
					(char *) newarray + overheadlen + lenbefore);

	return newarray;
}

/*----------------------------------------------------------------------------
 * array_set_slice :
 *		  This routine sets the value of a range of array locations (specified
 *		  by upper and lower index values ) to new values passed as
 *		  another array
 * result :
 *		  A new array is returned, just like the old except for the
 *		  modified range.
 *
 * 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 as the fetch operations do.  The reasoning
 * is that returning a NULL would cause the user's whole array to be replaced
 * with NULL, which will probably not make him happy.
 *----------------------------------------------------------------------------
 */
ArrayType *
array_set_slice(ArrayType *array,
				int nSubscripts,
				int *upperIndx,
				int *lowerIndx,
				ArrayType *srcArray,
				int arraylen,
				int elmlen,
				bool elmbyval,
				char elmalign,
				bool *isNull)
{
	int			i,
				ndim,
				dim[MAXDIM],
				lb[MAXDIM],
				span[MAXDIM];
	ArrayType  *newarray;
	int			nsrcitems,
				olddatasize,
				newsize,
				olditemsize,
				newitemsize,
				overheadlen,
				lenbefore,
				lenafter;

	if (array == (ArrayType *) NULL)
		RETURN_NULL(ArrayType *);
	if (srcArray == (ArrayType *) NULL)
		return array;

	if (arraylen > 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;
		int			nelems;
		Oid			elmtype = ARR_ELEMTYPE(array);

		deconstruct_array(srcArray, elmtype, elmlen, elmbyval, elmalign,
						  &dvalues, &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, nSubscripts, dim, lb, elmtype,
								  elmlen, elmbyval, elmalign);
	}

	if (ndim < nSubscripts || ndim <= 0 || ndim > MAXDIM)
		ereport(ERROR,
				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
				 errmsg("invalid 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));

	/*
	 * Check provided subscripts.  A slice exceeding the current array
	 * limits throws an error, *except* in the 1-D case where we will
	 * extend the array as long as no hole is created. An empty slice is
	 * an error, too.
	 */
	for (i = 0; i < nSubscripts; i++)
	{
		if (lowerIndx[i] > upperIndx[i])
			ereport(ERROR,
					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
					 errmsg("invalid array subscripts")));
		if (lowerIndx[i] < lb[i])
		{
			if (ndim == 1 && upperIndx[i] >= lb[i] - 1)
			{
				dim[i] += lb[i] - lowerIndx[i];
				lb[i] = lowerIndx[i];
			}
			else
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("invalid array subscripts")));
		}
		if (upperIndx[i] >= (dim[i] + lb[i]))
		{
			if (ndim == 1 && lowerIndx[i] <= (dim[i] + lb[i]))
				dim[i] = upperIndx[i] - lb[i] + 1;
			else
				ereport(ERROR,
						(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
						 errmsg("invalid array subscripts")));
		}
	}