index 05f630c6a6c59debc9c7824dc2fbf8d46dbe975e..223d869f8c8a2badaff203a5f8a094305b91b34f 100644 (file)
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>array_reverse</primary>
+ </indexterm>
+ <function>array_reverse</function> ( <type>anyarray</type> )
+ <returnvalue>anyarray</returnvalue>
+ </para>
+ <para>
+ Reverses the first dimension of the array.
+ </para>
+ <para>
+ <literal>array_reverse(ARRAY[[1,2],[3,4],[5,6]])</literal>
+ <returnvalue>{{5,6},{3,4},{1,2}}</returnvalue>
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
index 6599be2ec5e88bcf9a8cefecd0a5f2f0a1271dc2..d053808f6ee8ff452420bba23eb6811a5d9c43fe 100644 (file)
PG_RETURN_ARRAYTYPE_P(result);
}
+
+
+/*
+ * array_reverse_n
+ * Return a copy of array with reversed items.
+ *
+ * NOTE: it would be cleaner to look up the elmlen/elmbval/elmalign info
+ * from the system catalogs, given only the elmtyp. However, the caller is
+ * in a better position to cache this info across multiple calls.
+ */
+static ArrayType *
+array_reverse_n(ArrayType *array, Oid elmtyp, TypeCacheEntry *typentry)
+{
+ ArrayType *result;
+ int ndim,
+ *dims,
+ *lbs,
+ nelm,
+ nitem,
+ rdims[MAXDIM],
+ rlbs[MAXDIM];
+ int16 elmlen;
+ bool elmbyval;
+ char elmalign;
+ Datum *elms,
+ *ielms;
+ bool *nuls,
+ *inuls;
+
+ ndim = ARR_NDIM(array);
+ dims = ARR_DIMS(array);
+ lbs = ARR_LBOUND(array);
+
+ elmlen = typentry->typlen;
+ elmbyval = typentry->typbyval;
+ elmalign = typentry->typalign;
+
+ deconstruct_array(array, elmtyp, elmlen, elmbyval, elmalign,
+ &elms, &nuls, &nelm);
+
+ nitem = dims[0]; /* total number of items */
+ nelm /= nitem; /* number of elements per item */
+
+ /* Reverse the array */
+ ielms = elms;
+ inuls = nuls;
+ for (int i = 0; i < nitem / 2; i++)
+ {
+ int j = (nitem - i - 1) * nelm;
+ Datum *jelms = elms + j;
+ bool *jnuls = nuls + j;
+
+ /* Swap i'th and j'th items; advance ielms/inuls to next item */
+ for (int k = 0; k < nelm; k++)
+ {
+ Datum elm = *ielms;
+ bool nul = *inuls;
+
+ *ielms++ = *jelms;
+ *inuls++ = *jnuls;
+ *jelms++ = elm;
+ *jnuls++ = nul;
+ }
+ }
+
+ /* Set up dimensions of the result */
+ memcpy(rdims, dims, ndim * sizeof(int));
+ memcpy(rlbs, lbs, ndim * sizeof(int));
+ rdims[0] = nitem;
+
+ result = construct_md_array(elms, nuls, ndim, rdims, rlbs,
+ elmtyp, elmlen, elmbyval, elmalign);
+
+ pfree(elms);
+ pfree(nuls);
+
+ return result;
+}
+
+/*
+ * array_reverse
+ *
+ * Returns an array with the same dimensions as the input array, with its
+ * first-dimension elements in reverse order.
+ */
+Datum
+array_reverse(PG_FUNCTION_ARGS)
+{
+ ArrayType *array = PG_GETARG_ARRAYTYPE_P(0);
+ ArrayType *result;
+ Oid elmtyp;
+ TypeCacheEntry *typentry;
+
+ /*
+ * There is no point in reversing empty arrays or arrays with less than
+ * two items.
+ */
+ if (ARR_NDIM(array) < 1 || ARR_DIMS(array)[0] < 2)
+ PG_RETURN_ARRAYTYPE_P(array);
+
+ elmtyp = ARR_ELEMTYPE(array);
+ typentry = (TypeCacheEntry *) fcinfo->flinfo->fn_extra;
+ if (typentry == NULL || typentry->type_id != elmtyp)
+ {
+ typentry = lookup_type_cache(elmtyp, 0);
+ fcinfo->flinfo->fn_extra = (void *) typentry;
+ }
+
+ result = array_reverse_n(array, elmtyp, typentry);
+
+ PG_RETURN_ARRAYTYPE_P(result);
+}
index 0fc51a2160d1fdf4a08ced3e534bba007001e247..e968e915e993bb686fbde695e2a053d9f51e5338 100644 (file)
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 202410311
+#define CATALOG_VERSION_NO 202411011
#endif
index 1ec0d6f6b5fd2640f9a8540149afd2530e1b1189..a38e20f5d906d4ce99153daadb6b774dd5b43c1f 100644 (file)
{ oid => '6216', descr => 'take samples from array',
proname => 'array_sample', provolatile => 'v', prorettype => 'anyarray',
proargtypes => 'anyarray int4', prosrc => 'array_sample' },
+{ oid => '8686', descr => 'reverse array',
+ proname => 'array_reverse', prorettype => 'anyarray',
+ proargtypes => 'anyarray', prosrc => 'array_reverse' },
{ oid => '3816', descr => 'array typanalyze',
proname => 'array_typanalyze', provolatile => 's', prorettype => 'bool',
proargtypes => 'internal', prosrc => 'array_typanalyze' },
index a6d81fd5f9284c9af5e5faa6c280c9f59afadfd5..0b61fb5bb78fbba60978ba076e1c014dc99410ba 100644 (file)
@@ -2703,3 +2703,34 @@ SELECT array_sample('{1,2,3,4,5,6}'::int[], -1); -- fail
ERROR: sample size must be between 0 and 6
SELECT array_sample('{1,2,3,4,5,6}'::int[], 7); --fail
ERROR: sample size must be between 0 and 6
+-- array_reverse
+SELECT array_reverse('{}'::int[]);
+ array_reverse
+---------------
+ {}
+(1 row)
+
+SELECT array_reverse('{1}'::int[]);
+ array_reverse
+---------------
+ {1}
+(1 row)
+
+SELECT array_reverse('{1,2}'::int[]);
+ array_reverse
+---------------
+ {2,1}
+(1 row)
+
+SELECT array_reverse('{1,2,3,NULL,4,5,6}'::int[]);
+ array_reverse
+--------------------
+ {6,5,4,NULL,3,2,1}
+(1 row)
+
+SELECT array_reverse('{{1,2},{3,4},{5,6},{7,8}}'::int[]);
+ array_reverse
+---------------------------
+ {{7,8},{5,6},{3,4},{1,2}}
+(1 row)
+
index 47058dfde5092b557c070ae71df0e5aa538e490e..691cff4a124fdaf55f6a393137d2e78039bae833 100644 (file)
@@ -827,3 +827,10 @@ SELECT array_dims(array_sample('[-1:2][2:3]={{1,2},{3,NULL},{5,6},{7,8}}'::int[]
SELECT array_dims(array_sample('{{{1,2},{3,NULL}},{{5,6},{7,8}},{{9,10},{11,12}}}'::int[], 2));
SELECT array_sample('{1,2,3,4,5,6}'::int[], -1); -- fail
SELECT array_sample('{1,2,3,4,5,6}'::int[], 7); --fail
+
+-- array_reverse
+SELECT array_reverse('{}'::int[]);
+SELECT array_reverse('{1}'::int[]);
+SELECT array_reverse('{1,2}'::int[]);
+SELECT array_reverse('{1,2,3,NULL,4,5,6}'::int[]);
+SELECT array_reverse('{{1,2},{3,4},{5,6},{7,8}}'::int[]);
\ No newline at end of file