On Thu, Dec 22, 2022 at 10:08:17AM +0000, Dag Lem wrote:
>
> The calculation of quotient and remainder can be replaced by less costly
> masking and shifting.
>
> Defining
>
> #define OCT_DIGIT_BITS 3
> #define OCT_DIGIT_BITMASK 0x7
>
> the content of the loop can be replaced by
>
> *--ptr = digits[value & OCT_DIGIT_BITMASK];
> value >>= OCT_DIGIT_BITS;
>
> Also, the check for ptr > buf in the while loop can be removed. The
> check is superfluous, since buf cannot possibly be exhausted by a 32
> bit integer (the maximum octal number being 37777777777).
I integrated these suggestions in the attached -v2 patch and tested
range of values manually.
Also picked an OID > 8000 as suggested by unused_oids.
..Eric
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1f63dc6dba..b539e0dc0b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -3699,6 +3699,23 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>to_oct</primary>
+ </indexterm>
+ <function>to_oct</function> ( <type>integer</type> )
+ <returnvalue>text</returnvalue>
+ </para>
+ <para>
+ Converts the number to its equivalent octal representation.
+ </para>
+ <para>
+ <literal>to_oct(32)</literal>
+ <returnvalue>40</returnvalue>
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 1c52deec55..586693ad8f 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -5229,6 +5229,32 @@ to_hex64(PG_FUNCTION_ARGS)
PG_RETURN_TEXT_P(cstring_to_text(ptr));
}
+#define OCT_DIGIT_BITS 3
+#define OCT_DIGIT_BITMASK 0x7
+/*
+ * Convert an int32 to a string containing a base 8 (oct) representation of
+ * the number.
+ */
+Datum
+to_oct32(PG_FUNCTION_ARGS)
+{
+ uint32 value = (uint32) PG_GETARG_INT32(0);
+ char *ptr;
+ const char *digits = "01234567";
+ char buf[32]; /* bigger than needed, but
reasonable */
+
+ ptr = buf + sizeof(buf) - 1;
+ *ptr = '\0';
+
+ do
+ {
+ *--ptr = digits[value & OCT_DIGIT_BITMASK];
+ value >>= OCT_DIGIT_BITS;
+ } while (value);
+
+ PG_RETURN_TEXT_P(cstring_to_text(ptr));
+}
+
/*
* Return the size of a datum, possibly compressed
*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 98d90d9338..fde0b24563 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3687,6 +3687,9 @@
{ oid => '2090', descr => 'convert int8 number to hex',
proname => 'to_hex', prorettype => 'text', proargtypes => 'int8',
prosrc => 'to_hex64' },
+{ oid => '8335', descr => 'convert int4 number to oct',
+ proname => 'to_oct', prorettype => 'text', proargtypes => 'int4',
+ prosrc => 'to_oct32' },
# for character set encoding support
diff --git a/src/test/regress/expected/strings.out
b/src/test/regress/expected/strings.out
index f028c1f10f..5ebaeb4a80 100644
--- a/src/test/regress/expected/strings.out
+++ b/src/test/regress/expected/strings.out
@@ -2143,6 +2143,15 @@ select
to_hex(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "ffffffff"
ffffffff
(1 row)
+--
+-- test to_oct
+--
+select to_oct(256*256*256 - 1) AS "77777777";
+ 77777777
+----------
+ 77777777
+(1 row)
+
--
-- SHA-2
--
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
index 932f71cbca..c4c40949e7 100644
--- a/src/test/regress/sql/strings.sql
+++ b/src/test/regress/sql/strings.sql
@@ -691,6 +691,11 @@ select to_hex(256*256*256 - 1) AS "ffffff";
select to_hex(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS
"ffffffff";
+--
+-- test to_oct
+--
+select to_oct(256*256*256 - 1) AS "77777777";
+
--
-- SHA-2
--
