[CF 5176] v10 - Allow casting between bytea and integer types

Commitfest Bot · Commitfest Bot · commit ce1fa4a04318 · 2025-03-06T15:30:26.000Z
This branch was automatically generated by a robot using patches from an email thread registered at: https://commitfest.postgresql.org/patch/5176 The branch will be overwritten each time a new patch version is posted to the thread, and also periodically to check for bitrot caused by changes on the master branch. Patch(es): https://www.postgresql.org/message-id/CAEZATCUQhKQ+i-R2ELvNL4YFKq68Qb4QUNpa-zYFZF2OeoQp=w@mail.gmail.com Author(s): Aleksander Alekseev
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
@@ -5035,6 +5035,23 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
    </variablelist>
   </para>
 
+  <para>
+   In addition, it is possible to cast integral values to and from type
+   <type>bytea</type>. Casting an integer to <type>bytea</type> produces
+   2, 4, or 8 bytes, depending on the width of the integer type. The result
+   is the two's complement representation of the integer, with the most
+   significant byte first. Some examples:
+<programlisting>
+1234::smallint::bytea          <lineannotation>\x04d2</lineannotation>
+cast(1234 as bytea)            <lineannotation>\x000004d2</lineannotation>
+cast(-1234 as bytea)           <lineannotation>\xfffffb2e</lineannotation>
+'\x8000'::bytea::smallint      <lineannotation>-32768</lineannotation>
+'\x8000'::bytea::integer       <lineannotation>32768</lineannotation>
+</programlisting>
+   Casting a <type>bytea</type> to an integer will raise an error if the
+   length of the <type>bytea</type> exceeds the width of the integer type.
+  </para>
+
   <para>
    See also the aggregate function <function>string_agg</function> in
    <xref linkend="functions-aggregate"/> and the large object functions
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
@@ -4057,6 +4057,96 @@ bytea_sortsupport(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
+/* Cast bytea -> int2 */
+Datum
+bytea_int2(PG_FUNCTION_ARGS)
+{
+	bytea	   *v = PG_GETARG_BYTEA_PP(0);
+	int			len = VARSIZE_ANY_EXHDR(v);
+	uint16		result;
+
+	if (len > sizeof(result))
+		ereport(ERROR,
+				errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				errmsg("smallint out of range"));
+
+	result = 0;
+	for (int i = 0; i < len; i++)
+	{
+		result <<= BITS_PER_BYTE;
+		result |= ((unsigned char *) VARDATA_ANY(v))[i];
+	}
+
+	PG_RETURN_INT16(result);
+}
+
+/* Cast bytea -> int4 */
+Datum
+bytea_int4(PG_FUNCTION_ARGS)
+{
+	bytea	   *v = PG_GETARG_BYTEA_PP(0);
+	int			len = VARSIZE_ANY_EXHDR(v);
+	uint32		result;
+
+	if (len > sizeof(result))
+		ereport(ERROR,
+				errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				errmsg("integer out of range"));
+
+	result = 0;
+	for (int i = 0; i < len; i++)
+	{
+		result <<= BITS_PER_BYTE;
+		result |= ((unsigned char *) VARDATA_ANY(v))[i];
+	}
+
+	PG_RETURN_INT32(result);
+}
+
+/* Cast bytea -> int8 */
+Datum
+bytea_int8(PG_FUNCTION_ARGS)
+{
+	bytea	   *v = PG_GETARG_BYTEA_PP(0);
+	int			len = VARSIZE_ANY_EXHDR(v);
+	uint64		result;
+
+	if (len > sizeof(result))
+		ereport(ERROR,
+				errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				errmsg("bigint out of range"));
+
+	result = 0;
+	for (int i = 0; i < len; i++)
+	{
+		result <<= BITS_PER_BYTE;
+		result |= ((unsigned char *) VARDATA_ANY(v))[i];
+	}
+
+	PG_RETURN_INT64(result);
+}
+
+/* Cast int2 -> bytea; can just use int2send() */
+Datum
+int2_bytea(PG_FUNCTION_ARGS)
+{
+	return int2send(fcinfo);
+}
+
+/* Cast int4 -> bytea; can just use int4send() */
+Datum
+int4_bytea(PG_FUNCTION_ARGS)
+{
+	return int4send(fcinfo);
+}
+
+/* Cast int8 -> bytea; can just use int8send() */
+Datum
+int8_bytea(PG_FUNCTION_ARGS)
+{
+	return int8send(fcinfo);
+}
+
 /*
  * appendStringInfoText
  *
diff --git a/src/include/catalog/pg_cast.dat b/src/include/catalog/pg_cast.dat
@@ -320,6 +320,20 @@
 { castsource => 'varchar', casttarget => 'name', castfunc => 'name(varchar)',
   castcontext => 'i', castmethod => 'f' },
 
+# Allow explicit coercions between bytea and integer types
+{ castsource => 'int2', casttarget => 'bytea', castfunc => 'bytea(int2)',
+  castcontext => 'e', castmethod => 'f' },
+{ castsource => 'int4', casttarget => 'bytea', castfunc => 'bytea(int4)',
+  castcontext => 'e', castmethod => 'f' },
+{ castsource => 'int8', casttarget => 'bytea', castfunc => 'bytea(int8)',
+  castcontext => 'e', castmethod => 'f' },
+{ castsource => 'bytea', casttarget => 'int2', castfunc => 'int2(bytea)',
+  castcontext => 'e', castmethod => 'f' },
+{ castsource => 'bytea', casttarget => 'int4', castfunc => 'int4(bytea)',
+  castcontext => 'e', castmethod => 'f' },
+{ castsource => 'bytea', casttarget => 'int8', castfunc => 'int8(bytea)',
+  castcontext => 'e', castmethod => 'f' },
+
 # Allow explicit coercions between int4 and "char"
 { castsource => 'char', casttarget => 'int4', castfunc => 'int4(char)',
   castcontext => 'e', castmethod => 'f' },
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
@@ -1165,6 +1165,25 @@
   proname => 'name', proleakproof => 't', prorettype => 'name',
   proargtypes => 'bpchar', prosrc => 'bpchar_name' },
 
+{ oid => '8577', descr => 'convert int2 to bytea',
+  proname => 'bytea', proleakproof => 't', prorettype => 'bytea',
+  proargtypes => 'int2', prosrc => 'int2_bytea' },
+{ oid => '8578', descr => 'convert int4 to bytea',
+  proname => 'bytea', proleakproof => 't', prorettype => 'bytea',
+  proargtypes => 'int4', prosrc => 'int4_bytea' },
+{ oid => '8579', descr => 'convert int8 to bytea',
+  proname => 'bytea', proleakproof => 't', prorettype => 'bytea',
+  proargtypes => 'int8', prosrc => 'int8_bytea' },
+{ oid => '8580', descr => 'convert bytea to int2',
+  proname => 'int2', prorettype => 'int2',
+  proargtypes => 'bytea', prosrc => 'bytea_int2' },
+{ oid => '8581', descr => 'convert bytea to int4',
+  proname => 'int4', prorettype => 'int4',
+  proargtypes => 'bytea', prosrc => 'bytea_int4' },
+{ oid => '8582', descr => 'convert bytea to int8',
+  proname => 'int8', prorettype => 'int8',
+  proargtypes => 'bytea', prosrc => 'bytea_int8' },
+
 { oid => '449', descr => 'hash',
   proname => 'hashint2', prorettype => 'int4', proargtypes => 'int2',
   prosrc => 'hashint2' },
diff --git a/src/test/regress/expected/opr_sanity.out b/src/test/regress/expected/opr_sanity.out
@@ -875,6 +875,9 @@ uuid_extract_timestamp(uuid)
 uuid_extract_version(uuid)
 crc32(bytea)
 crc32c(bytea)
+bytea(smallint)
+bytea(integer)
+bytea(bigint)
 bytea_larger(bytea,bytea)
 bytea_smaller(bytea,bytea)
 -- Check that functions without argument are not marked as leakproof.
diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out
@@ -2358,6 +2358,108 @@ SELECT set_byte('\x1234567890abcdef00'::bytea, 7, 11);
 
 SELECT set_byte('\x1234567890abcdef00'::bytea, 99, 11);  -- error
 ERROR:  index 99 out of valid range, 0..8
+--
+-- conversions between bytea and integer types
+--
+SELECT 0x1234::int2::bytea AS "\x1234", (-0x1234)::int2::bytea AS "\xedcc";
+ \x1234 | \xedcc 
+--------+--------
+ \x1234 | \xedcc
+(1 row)
+
+SELECT 0x12345678::int4::bytea AS "\x12345678", (-0x12345678)::int4::bytea AS "\xedcba988";
+ \x12345678 | \xedcba988 
+------------+------------
+ \x12345678 | \xedcba988
+(1 row)
+
+SELECT 0x1122334455667788::int8::bytea AS "\x1122334455667788",
+       (-0x1122334455667788)::int8::bytea AS "\xeeddccbbaa998878";
+ \x1122334455667788 | \xeeddccbbaa998878 
+--------------------+--------------------
+ \x1122334455667788 | \xeeddccbbaa998878
+(1 row)
+
+SELECT ''::bytea::int2 AS "0";
+ 0 
+---
+ 0
+(1 row)
+
+SELECT '\x12'::bytea::int2 AS "18";
+ 18 
+----
+ 18
+(1 row)
+
+SELECT '\x1234'::bytea::int2 AS "4460";
+ 4460 
+------
+ 4660
+(1 row)
+
+SELECT '\x123456'::bytea::int2; -- error
+ERROR:  smallint out of range
+SELECT ''::bytea::int4 AS "0";
+ 0 
+---
+ 0
+(1 row)
+
+SELECT '\x12'::bytea::int4 AS "18";
+ 18 
+----
+ 18
+(1 row)
+
+SELECT '\x12345678'::bytea::int4 AS "305419896";
+ 305419896 
+-----------
+ 305419896
+(1 row)
+
+SELECT '\x123456789A'::bytea::int4; -- error
+ERROR:  integer out of range
+SELECT ''::bytea::int8 AS "0";
+ 0 
+---
+ 0
+(1 row)
+
+SELECT '\x12'::bytea::int8 AS "18";
+ 18 
+----
+ 18
+(1 row)
+
+SELECT '\x1122334455667788'::bytea::int8 AS "1234605616436508552";
+ 1234605616436508552 
+---------------------
+ 1234605616436508552
+(1 row)
+
+SELECT '\x112233445566778899'::bytea::int8; -- error
+ERROR:  bigint out of range
+-- min/max integer values
+SELECT '\x8000'::bytea::int2 AS "-32768", '\x7FFF'::bytea::int2 AS "32767";
+ -32768 | 32767 
+--------+-------
+ -32768 | 32767
+(1 row)
+
+SELECT '\x80000000'::bytea::int4 AS "-2147483648", '\x7FFFFFFF'::bytea::int4 AS "2147483647";
+ -2147483648 | 2147483647 
+-------------+------------
+ -2147483648 | 2147483647
+(1 row)
+
+SELECT '\x8000000000000000'::bytea::int8 AS "-9223372036854775808",
+       '\x7FFFFFFFFFFFFFFF'::bytea::int8 AS "9223372036854775807";
+ -9223372036854775808 | 9223372036854775807 
+----------------------+---------------------
+ -9223372036854775808 | 9223372036854775807
+(1 row)
+
 --
 -- test behavior of escape_string_warning and standard_conforming_strings options
 --
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
@@ -751,6 +751,35 @@ SELECT get_byte('\x1234567890abcdef00'::bytea, 99);  -- error
 SELECT set_byte('\x1234567890abcdef00'::bytea, 7, 11);
 SELECT set_byte('\x1234567890abcdef00'::bytea, 99, 11);  -- error
 
+--
+-- conversions between bytea and integer types
+--
+SELECT 0x1234::int2::bytea AS "\x1234", (-0x1234)::int2::bytea AS "\xedcc";
+SELECT 0x12345678::int4::bytea AS "\x12345678", (-0x12345678)::int4::bytea AS "\xedcba988";
+SELECT 0x1122334455667788::int8::bytea AS "\x1122334455667788",
+       (-0x1122334455667788)::int8::bytea AS "\xeeddccbbaa998878";
+
+SELECT ''::bytea::int2 AS "0";
+SELECT '\x12'::bytea::int2 AS "18";
+SELECT '\x1234'::bytea::int2 AS "4460";
+SELECT '\x123456'::bytea::int2; -- error
+
+SELECT ''::bytea::int4 AS "0";
+SELECT '\x12'::bytea::int4 AS "18";
+SELECT '\x12345678'::bytea::int4 AS "305419896";
+SELECT '\x123456789A'::bytea::int4; -- error
+
+SELECT ''::bytea::int8 AS "0";
+SELECT '\x12'::bytea::int8 AS "18";
+SELECT '\x1122334455667788'::bytea::int8 AS "1234605616436508552";
+SELECT '\x112233445566778899'::bytea::int8; -- error
+
+-- min/max integer values
+SELECT '\x8000'::bytea::int2 AS "-32768", '\x7FFF'::bytea::int2 AS "32767";
+SELECT '\x80000000'::bytea::int4 AS "-2147483648", '\x7FFFFFFF'::bytea::int4 AS "2147483647";
+SELECT '\x8000000000000000'::bytea::int8 AS "-9223372036854775808",
+       '\x7FFFFFFFFFFFFFFF'::bytea::int8 AS "9223372036854775807";
+
 --
 -- test behavior of escape_string_warning and standard_conforming_strings options
 --
