Tweak behavior of array slicing operations: seems like it ought to be

okay to omit low-order dimensions when accessing an array slice.

diff --git a/src/backend/utils/adt/arrayfuncs.c b/src/backend/utils/adt/arrayfuncs.c
index 4458f71af782c2411ad2069526267c729dd28617..f69f06359ba79d970d417fbde9822e07e2d21c73 100644 (file)
--- a/src/backend/utils/adt/arrayfuncs.c
+++ b/src/backend/utils/adt/arrayfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.76 2002/03/16 22:47:13 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.77 2002/03/20 19:41:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -907,10 +907,10 @@ array_get_slice(ArrayType *array,
         * with an empty slice, return NULL (should it be an empty array
         * instead?)
         */
-       if (ndim != nSubscripts || ndim <= 0 || ndim > MAXDIM)
+       if (ndim < nSubscripts || ndim <= 0 || ndim > MAXDIM)
                RETURN_NULL(ArrayType *);
 
-       for (i = 0; i < ndim; i++)
+       for (i = 0; i < nSubscripts; i++)
        {
                if (lowerIndx[i] < lb[i])
                        lowerIndx[i] = lb[i];
@@ -919,8 +919,16 @@ array_get_slice(ArrayType *array,
                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(nSubscripts, span, lowerIndx, upperIndx);
+       mda_get_range(ndim, span, lowerIndx, upperIndx);
 
        bytes = array_slice_size(ndim, dim, lb, arraydataptr,
                                                         elmlen, lowerIndx, upperIndx);
@@ -1120,6 +1128,9 @@ array_set(ArrayType *array,
  *               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
@@ -1172,7 +1183,7 @@ array_set_slice(ArrayType *array,
        /* note: we assume srcArray contains no toasted elements */
 
        ndim = ARR_NDIM(array);
-       if (ndim != nSubscripts || ndim <= 0 || ndim > MAXDIM)
+       if (ndim < nSubscripts || ndim <= 0 || ndim > MAXDIM)
                elog(ERROR, "Invalid array subscripts");
 
        /* copy dim/lb since we may modify them */
@@ -1185,7 +1196,7 @@ array_set_slice(ArrayType *array,
         * extend the array as long as no hole is created. An empty slice is
         * an error, too.
         */
-       for (i = 0; i < ndim; i++)
+       for (i = 0; i < nSubscripts; i++)
        {
                if (lowerIndx[i] > upperIndx[i])
                        elog(ERROR, "Invalid array subscripts");
@@ -1207,6 +1218,14 @@ array_set_slice(ArrayType *array,
                                elog(ERROR, "Invalid array subscripts");
                }
        }
+       /* 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])
+                       elog(ERROR, "Invalid array subscripts");
+       }
 
        /*
         * Make sure source array has enough entries.  Note we ignore the