pg.ddx.io pgsql-hackers@postgresql.org mailing list archive help / color / mirror / Atom feed From: Nathan Bossart <nathandbossart@gmail.com>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: John Naylor <john.naylor@enterprisedb.com>
Cc: Kirk Wolak <wolakk@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Cc: Eric Radman <ericshane@eradman.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: [PATCH] Add function to_oct
Date: Sun, 20 Aug 2023 08:25:51 -0700
Message-ID: <20230820152551.GB290672@nathanxps13> (raw )
In-Reply-To: <CAEZATCWaQ+-7A9AxxUcxdhdOa4p54rSvKreHMXhnTJg6VuAURQ@mail.gmail.com >
References: <20230726001656.GC2992317@nathanxps13 >
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<CAFBsxsGkBKO276L476BWDgNGbkaH0S_ZcnevOK_0s=Dz0=Utrw@mail.gmail.com >
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<CAFBsxsEm0VGAipmQNK-EZ1a8ej6PDF+2aEkYGbktKH9aHFb4Dw@mail.gmail.com >
<20230816142410.GA2651383@nathanxps13 >
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<20230817152628.GA3148583@nathanxps13 >
<CAEZATCWaQ+-7A9AxxUcxdhdOa4p54rSvKreHMXhnTJg6VuAURQ@mail.gmail.com >
On Sat, Aug 19, 2023 at 08:35:46AM +0100, Dean Rasheed wrote:
> I note that there are no tests for negative inputs.
I added some in v8.
> Doing a quick test, shows that this changes the current behaviour,
> because all inputs are now treated as 64-bit:
>
> HEAD:
>
> select to_hex((-1234)::int);
> to_hex
> ----------
> fffffb2e
>
> With patch:
>
> select to_hex((-1234)::int);
> to_hex
> ------------------
> fffffffffffffb2e
Good catch. In v8, I fixed this by first casting the input to uint32 for
the 32-bit versions of the functions. This prevents the conversion to
uint64 from setting the rest of the bits. AFAICT this behavior is pretty
well defined in the standard.
> The way that negative inputs are handled really should be documented,
> or at least it should include a couple of examples.
I used your suggestion and noted that the output is the two's complement
representation [0].
[0] https://postgr.es/m/CAEZATCVbkL1ynqpsKiTDpch34%3DSCr5nnau%3DnfNmiy2nM3SJHtw%40mail.gmail.com
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
Attachments:
v8-0001-add-to_binary-and-to_oct.patch (text/x-diff, 9.8K) download
From a03c06d0b26ccbd49bda55c2efab565ab9fa90db Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathan@postgresql.org>
Date: Tue, 25 Jul 2023 16:09:01 -0700
Subject: [PATCH v8 1/1] add to_binary() and to_oct()
---
doc/src/sgml/func.sgml | 47 ++++++++++++++-
src/backend/utils/adt/varlena.c | 86 +++++++++++++++++++--------
src/include/catalog/pg_proc.dat | 12 ++++
src/test/regress/expected/strings.out | 62 ++++++++++++++++++-
src/test/regress/sql/strings.sql | 15 ++++-
5 files changed, 192 insertions(+), 30 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..835c08905e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -3737,6 +3737,50 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>to_binary</primary>
+ </indexterm>
+ <function>to_binary</function> ( <type>integer</type> )
+ <returnvalue>text</returnvalue>
+ </para>
+ <para role="func_signature">
+ <function>to_binary</function> ( <type>bigint</type> )
+ <returnvalue>text</returnvalue>
+ </para>
+ <para>
+ Converts the number to its equivalent two's complement binary
+ representation.
+ </para>
+ <para>
+ <literal>to_binary(2147483647)</literal>
+ <returnvalue>1111111111111111111111111111111</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 role="func_signature">
+ <function>to_oct</function> ( <type>bigint</type> )
+ <returnvalue>text</returnvalue>
+ </para>
+ <para>
+ Converts the number to its equivalent two's complement octal
+ representation.
+ </para>
+ <para>
+ <literal>to_oct(2147483647)</literal>
+ <returnvalue>17777777777</returnvalue>
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
@@ -3750,7 +3794,8 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
<returnvalue>text</returnvalue>
</para>
<para>
- Converts the number to its equivalent hexadecimal representation.
+ Converts the number to its equivalent two's complement hexadecimal
+ representation.
</para>
<para>
<literal>to_hex(2147483647)</literal>
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index b1ec5c32ce..cac3577480 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -4919,53 +4919,87 @@ array_to_text_internal(FunctionCallInfo fcinfo, ArrayType *v,
return result;
}
-#define HEXBASE 16
/*
- * Convert an int32 to a string containing a base 16 (hex) representation of
- * the number.
+ * Workhorse for to_binary, to_oct, and to_hex. Note that base must be > 1 and
+ * <= 16.
*/
-Datum
-to_hex32(PG_FUNCTION_ARGS)
+static inline text *
+convert_to_base(uint64 value, int base)
{
- uint32 value = (uint32) PG_GETARG_INT32(0);
- char *ptr;
const char *digits = "0123456789abcdef";
- char buf[32]; /* bigger than needed, but reasonable */
- ptr = buf + sizeof(buf) - 1;
- *ptr = '\0';
+ /* We size the buffer for to_binary's longest possible return value. */
+ char buf[sizeof(uint64) * BITS_PER_BYTE];
+ char *const end = buf + sizeof(buf);
+ char *ptr = end;
+
+ Assert(base > 1);
+ Assert(base <= 16);
do
{
- *--ptr = digits[value % HEXBASE];
- value /= HEXBASE;
+ *--ptr = digits[value % base];
+ value /= base;
} while (ptr > buf && value);
- PG_RETURN_TEXT_P(cstring_to_text(ptr));
+ return cstring_to_text_with_len(ptr, end - ptr);
+}
+
+/*
+ * Convert an integer to a string containing a base-2 (binary) representation
+ * of the number.
+ */
+Datum
+to_binary32(PG_FUNCTION_ARGS)
+{
+ uint64 value = (uint32) PG_GETARG_INT32(0);
+
+ PG_RETURN_TEXT_P(convert_to_base(value, 2));
+}
+Datum
+to_binary64(PG_FUNCTION_ARGS)
+{
+ uint64 value = (uint64) PG_GETARG_INT64(0);
+
+ PG_RETURN_TEXT_P(convert_to_base(value, 2));
}
/*
- * Convert an int64 to a string containing a base 16 (hex) representation of
+ * Convert an integer to a string containing a base-8 (oct) representation of
* the number.
*/
Datum
-to_hex64(PG_FUNCTION_ARGS)
+to_oct32(PG_FUNCTION_ARGS)
+{
+ uint64 value = (uint32) PG_GETARG_INT32(0);
+
+ PG_RETURN_TEXT_P(convert_to_base(value, 8));
+}
+Datum
+to_oct64(PG_FUNCTION_ARGS)
{
uint64 value = (uint64) PG_GETARG_INT64(0);
- char *ptr;
- const char *digits = "0123456789abcdef";
- char buf[32]; /* bigger than needed, but reasonable */
- ptr = buf + sizeof(buf) - 1;
- *ptr = '\0';
+ PG_RETURN_TEXT_P(convert_to_base(value, 8));
+}
- do
- {
- *--ptr = digits[value % HEXBASE];
- value /= HEXBASE;
- } while (ptr > buf && value);
+/*
+ * Convert an integer to a string containing a base-16 (hex) representation of
+ * the number.
+ */
+Datum
+to_hex32(PG_FUNCTION_ARGS)
+{
+ uint64 value = (uint32) PG_GETARG_INT32(0);
+
+ PG_RETURN_TEXT_P(convert_to_base(value, 16));
+}
+Datum
+to_hex64(PG_FUNCTION_ARGS)
+{
+ uint64 value = (uint64) PG_GETARG_INT64(0);
- PG_RETURN_TEXT_P(cstring_to_text(ptr));
+ PG_RETURN_TEXT_P(convert_to_base(value, 16));
}
/*
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 12fac15ceb..b653351605 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -3707,6 +3707,18 @@
{ oid => '2768', descr => 'split string by pattern',
proname => 'regexp_split_to_array', prorettype => '_text',
proargtypes => 'text text text', prosrc => 'regexp_split_to_array' },
+{ oid => '9030', descr => 'convert int4 number to binary',
+ proname => 'to_binary', prorettype => 'text', proargtypes => 'int4',
+ prosrc => 'to_binary32' },
+{ oid => '9031', descr => 'convert int8 number to binary',
+ proname => 'to_binary', prorettype => 'text', proargtypes => 'int8',
+ prosrc => 'to_binary64' },
+{ oid => '9032', descr => 'convert int4 number to oct',
+ proname => 'to_oct', prorettype => 'text', proargtypes => 'int4',
+ prosrc => 'to_oct32' },
+{ oid => '9033', descr => 'convert int8 number to oct',
+ proname => 'to_oct', prorettype => 'text', proargtypes => 'int8',
+ prosrc => 'to_oct64' },
{ oid => '2089', descr => 'convert int4 number to hex',
proname => 'to_hex', prorettype => 'text', proargtypes => 'int4',
prosrc => 'to_hex32' },
diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out
index 62698569e1..d24e6fa0cd 100644
--- a/src/test/regress/expected/strings.out
+++ b/src/test/regress/expected/strings.out
@@ -2129,8 +2129,68 @@ select split_part('@joeuser@mydatabase@','@',-2) AS "mydatabase";
(1 row)
--
--- test to_hex
+-- test to_binary, to_oct, and to_hex
--
+select to_binary(-1234) AS "11111111111111111111101100101110";
+ 11111111111111111111101100101110
+----------------------------------
+ 11111111111111111111101100101110
+(1 row)
+
+select to_binary(-1234::bigint);
+ to_binary
+------------------------------------------------------------------
+ 1111111111111111111111111111111111111111111111111111101100101110
+(1 row)
+
+select to_binary(256*256*256 - 1) AS "111111111111111111111111";
+ 111111111111111111111111
+--------------------------
+ 111111111111111111111111
+(1 row)
+
+select to_binary(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "11111111111111111111111111111111";
+ 11111111111111111111111111111111
+----------------------------------
+ 11111111111111111111111111111111
+(1 row)
+
+select to_oct(-1234) AS "37777775456";
+ 37777775456
+-------------
+ 37777775456
+(1 row)
+
+select to_oct(-1234::bigint) AS "1777777777777777775456";
+ 1777777777777777775456
+------------------------
+ 1777777777777777775456
+(1 row)
+
+select to_oct(256*256*256 - 1) AS "77777777";
+ 77777777
+----------
+ 77777777
+(1 row)
+
+select to_oct(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "37777777777";
+ 37777777777
+-------------
+ 37777777777
+(1 row)
+
+select to_hex(-1234) AS "fffffb2e";
+ fffffb2e
+----------
+ fffffb2e
+(1 row)
+
+select to_hex(-1234::bigint) AS "fffffffffffffb2e";
+ fffffffffffffb2e
+------------------
+ fffffffffffffb2e
+(1 row)
+
select to_hex(256*256*256 - 1) AS "ffffff";
ffffff
--------
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
index ca32f6bba5..437713fdc6 100644
--- a/src/test/regress/sql/strings.sql
+++ b/src/test/regress/sql/strings.sql
@@ -685,10 +685,21 @@ select split_part('joeuser@mydatabase','@',-3) AS "empty string";
select split_part('@joeuser@mydatabase@','@',-2) AS "mydatabase";
--
--- test to_hex
+-- test to_binary, to_oct, and to_hex
--
-select to_hex(256*256*256 - 1) AS "ffffff";
+select to_binary(-1234) AS "11111111111111111111101100101110";
+select to_binary(-1234::bigint);
+select to_binary(256*256*256 - 1) AS "111111111111111111111111";
+select to_binary(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "11111111111111111111111111111111";
+
+select to_oct(-1234) AS "37777775456";
+select to_oct(-1234::bigint) AS "1777777777777777775456";
+select to_oct(256*256*256 - 1) AS "77777777";
+select to_oct(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "37777777777";
+select to_hex(-1234) AS "fffffb2e";
+select to_hex(-1234::bigint) AS "fffffffffffffb2e";
+select to_hex(256*256*256 - 1) AS "ffffff";
select to_hex(256::bigint*256::bigint*256::bigint*256::bigint - 1) AS "ffffffff";
--
--
2.25.1
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Cc: nathandbossart@gmail.com, dean.a.rasheed@gmail.com, john.naylor@enterprisedb.com, wolakk@gmail.com, peter.eisentraut@enterprisedb.com, ericshane@eradman.com
Subject: Re: [PATCH] Add function to_oct
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