ADD array_ndims function

Author: Robert Haas <robertmhaas@gmail.com>

doc/src/sgml/func.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.454 2008/11/04 00:59:45 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.455 2008/11/04 14:49:11 petere Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -9373,6 +9373,17 @@ SELECT NULLIF(value, '(none)') ...
         <entry><literal>array_cat(ARRAY[1,2,3], ARRAY[4,5])</literal></entry>
         <entry><literal>{1,2,3,4,5}</literal></entry>
        </row>
+       <row>
+        <entry>
+         <literal>
+          <function>array_ndims</function>(<type>anyarray</type>)
+         </literal>
+        </entry>
+        <entry><type>int</type></entry>
+        <entry>returns the number of dimensions of the array</entry>
+        <entry><literal>array_ndims(ARRAY[[1,2,3], [4,5,6]])</literal></entry>
+        <entry><literal>2</literal></entry>
+       </row>
        <row>
         <entry>
          <literal>

src/backend/utils/adt/arrayfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.147 2008/07/21 04:47:00 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/arrayfuncs.c,v 1.148 2008/11/04 14:49:11 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1530,6 +1530,22 @@ array_send(PG_FUNCTION_ARGS)
 	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
 }
 
+/*
+ * array_ndims :
+ *        returns the number of dimensions of the array pointed to by "v"
+ */
+Datum
+array_ndims(PG_FUNCTION_ARGS)
+{
+	ArrayType  *v = PG_GETARG_ARRAYTYPE_P(0);
+
+	/* Sanity check: does it look like an array at all? */
+	if (ARR_NDIM(v) <= 0 || ARR_NDIM(v) > MAXDIM)
+		PG_RETURN_NULL();
+
+	PG_RETURN_INT32(ARR_NDIM(v));
+}
+
 /*
  * array_dims :
  *		  returns the dimensions of the array pointed to by "v", as a "text"

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.501 2008/11/03 17:51:13 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.502 2008/11/04 14:49:11 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200811031
+#define CATALOG_VERSION_NO	200811041
 
 #endif

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.523 2008/11/03 21:09:17 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.524 2008/11/04 14:49:11 petere Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -985,6 +985,7 @@ DATA(insert OID = 393 (  array_le		   PGNSP PGUID 12 1 0 0 f f t f i 2 16 "2277
 DESCR("array less than or equal");
 DATA(insert OID = 396 (  array_ge		   PGNSP PGUID 12 1 0 0 f f t f i 2 16 "2277 2277" _null_ _null_ _null_ array_ge _null_ _null_ _null_ ));
 DESCR("array greater than or equal");
+DATA(insert OID = 748 (  array_ndims	   PGNSP PGUID 12 1 0 0 f f t f i 1 23 "2277" _null_ _null_ _null_ array_ndims _null_ _null_ _null_ ));
 DATA(insert OID = 747 (  array_dims		   PGNSP PGUID 12 1 0 0 f f t f i 1 25 "2277" _null_ _null_ _null_ array_dims _null_ _null_ _null_ ));
 DESCR("array dimensions");
 DATA(insert OID = 750 (  array_in		   PGNSP PGUID 12 1 0 0 f f t f s 3 2277 "2275 26 23" _null_ _null_ _null_	array_in _null_ _null_ _null_ ));

src/include/utils/array.h

@@ -49,7 +49,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/array.h,v 1.68 2008/07/16 00:48:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/utils/array.h,v 1.69 2008/11/04 14:49:12 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -195,6 +195,7 @@ extern Datum btarraycmp(PG_FUNCTION_ARGS);
 extern Datum arrayoverlap(PG_FUNCTION_ARGS);
 extern Datum arraycontains(PG_FUNCTION_ARGS);
 extern Datum arraycontained(PG_FUNCTION_ARGS);
+extern Datum array_ndims(PG_FUNCTION_ARGS);
 extern Datum array_dims(PG_FUNCTION_ARGS);
 extern Datum array_lower(PG_FUNCTION_ARGS);
 extern Datum array_upper(PG_FUNCTION_ARGS);

src/test/regress/expected/arrays.out

@@ -68,6 +68,15 @@ SELECT a[1:3],
  {}         | {}              | {foo,bar} | {}
 (3 rows)
 
+SELECT array_ndims(a) AS a,array_ndims(b) AS b,array_ndims(c) AS c
+   FROM arrtest;
+ a | b | c 
+---+---+---
+ 1 | 3 |  
+ 1 | 2 | 1
+   | 1 | 1
+(3 rows)
+
 SELECT array_dims(a) AS a,array_dims(b) AS b,array_dims(c) AS c
    FROM arrtest;
    a   |        b        |   c   

src/test/regress/sql/arrays.sql

@@ -53,6 +53,9 @@ SELECT a[1:3],
           d[1:1][1:2]
    FROM arrtest;
 
+SELECT array_ndims(a) AS a,array_ndims(b) AS b,array_ndims(c) AS c
+   FROM arrtest;
+
 SELECT array_dims(a) AS a,array_dims(b) AS b,array_dims(c) AS c
    FROM arrtest;