0001-Implement-custom-int-248-string-conversion-routines-.patch

From 55acfa4f971f5a0e33eb8b9e66d621c16be96d42 Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Fri, 19 Nov 2010 21:44:29 +0100
Subject: [PATCH] Implement custom int[248]->string conversion routines out of speed reasons.

---
 src/backend/utils/adt/int8.c       |   10 +--
 src/backend/utils/adt/numutils.c   |  130 ++++++++++++++++++++++++++++++++----
 src/include/utils/builtins.h       |    1 +
 src/test/regress/expected/int2.out |   13 ++++
 src/test/regress/expected/int4.out |   13 ++++
 src/test/regress/expected/int8.out |   13 ++++
 src/test/regress/sql/int2.sql      |    4 +
 src/test/regress/sql/int4.sql      |    4 +
 src/test/regress/sql/int8.sql      |    4 +
 9 files changed, 172 insertions(+), 20 deletions(-)

diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index 894110d..8f4ef5a 100644
*** a/src/backend/utils/adt/int8.c
--- b/src/backend/utils/adt/int8.c
***************
*** 20,25 ****
--- 20,26 ----
  #include "funcapi.h"
  #include "libpq/pqformat.h"
  #include "utils/int8.h"
+ #include "utils/builtins.h"
  
  
  #define MAXINT8LEN		25
*************** Datum
*** 157,170 ****
  int8out(PG_FUNCTION_ARGS)
  {
  	int64		val = PG_GETARG_INT64(0);
! 	char	   *result;
! 	int			len;
! 	char		buf[MAXINT8LEN + 1];
! 
! 	if ((len = snprintf(buf, MAXINT8LEN, INT64_FORMAT, val)) < 0)
! 		elog(ERROR, "could not format int8");
  
! 	result = pstrdup(buf);
  	PG_RETURN_CSTRING(result);
  }
  
--- 158,166 ----
  int8out(PG_FUNCTION_ARGS)
  {
  	int64		val = PG_GETARG_INT64(0);
! 	char	   *result = palloc(MAXINT8LEN + 1);
  
! 	pg_lltoa(val, result);
  	PG_RETURN_CSTRING(result);
  }
  
diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c
index 5f8083f..7b50549 100644
*** a/src/backend/utils/adt/numutils.c
--- b/src/backend/utils/adt/numutils.c
***************
*** 3,10 ****
   * numutils.c
   *	  utility functions for I/O of built-in numeric types.
   *
-  *		integer:				pg_atoi, pg_itoa, pg_ltoa
-  *
   * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
--- 3,8 ----
*************** pg_atoi(char *s, int size, int c)
*** 109,135 ****
  }
  
  /*
!  *		pg_itoa			- converts a short int to its string represention
   *
!  *		Note:
!  *				previously based on ~ingres/source/gutil/atoi.c
!  *				now uses vendor's sprintf conversion
   */
  void
  pg_itoa(int16 i, char *a)
  {
! 	sprintf(a, "%hd", (short) i);
  }
  
  /*
!  *		pg_ltoa			- converts a long int to its string represention
   *
!  *		Note:
!  *				previously based on ~ingres/source/gutil/atoi.c
!  *				now uses vendor's sprintf conversion
   */
  void
! pg_ltoa(int32 l, char *a)
  {
! 	sprintf(a, "%d", l);
  }
--- 107,239 ----
  }
  
  /*
!  * pg_ltoa - convert a signed 16bit integer to its string representation
   *
!  * It doesnt seem worth implementing this separately.
   */
  void
  pg_itoa(int16 i, char *a)
  {
! 	pg_ltoa((int32)i, a);
  }
  
+ 
  /*
!  * pg_ltoa: convert a signed 32bit integer to its string representation
   *
!  * 'buf' has to be 12 bytes long to fit the result of any 32bit integer.
!  *
!  * Its unfortunate to have this function twice - once for 32bit, once
!  * for 64bit, but incurring the cost of 64bit computation to 32bit
!  * platforms doesn't seem to be acceptable.
   */
  void
! pg_ltoa(int32 value, char *buf)
  {
! 	char *bufstart = buf;
! 	bool neg = false;
! 
! 	/*
! 	 * Avoid problems with the most negative not being representable
! 	 * as a positive integer
! 	 */
! 	if (value == INT32_MIN)
! 	{
! 		memcpy(buf, "-2147483648", 12);
! 		return;
! 	}
! 	else if (value < 0)
! 	{
! 		value = -value;
! 		neg = true;
! 	}
! 
! 	/* Build the string by computing the wanted string backwards. */
! 	do
! 	{
! 		int32 remainder;
! 		int32 oldval = value;
! 		/*
! 		 * division by constants can be optimized by some modern
! 		 * compilers (including gcc). We could add the concrete,
! 		 * optimized, calculatation here to be fast at -O0 and/or
! 		 * other compilers... Not sure if its worth doing.
! 		 */
! 		value /= 10;
! 		remainder = oldval - value * 10;
! 		*buf++ = '0' + remainder;
! 	}
! 	while (value != 0);
! 
! 	if (neg)
! 		*buf++ = '-';
! 
! 	/* have to reorder the string, but not 0 byte */
! 	*buf-- = 0;
! 
! 	/* reverse string */
! 	while (bufstart < buf)
! 	{
! 		char swap = *bufstart;
! 		*bufstart++ = *buf;
! 		*buf-- = swap;
! 	}
! }
! 
! /*
!  * pg_lltoa: convert a signed 64bit integer to its string representation
!  *
!  * 'buf' has to be MAXINT8LEN + 1 bytes long to fit the result of any
!  * 74bit integer.
!  */
! void pg_lltoa(int64 value, char *buf)
! {
! 	char *bufstart = buf;
! 	bool neg = false;
! 
! 	/*
! 	 * Avoid problems with the most negative not being representable as
! 	 * a positive integer
! 	 */
! 	if (value == INT64_MIN)
! 	{
! 		memcpy(buf, "-9223372036854775808", 21);
! 		return;
! 	}
! 	else if (value < 0)
! 	{
! 		value = -value;
! 		neg = true;
! 	}
! 
! 	/* Build the string by computing the wanted string backwards. */
! 	do
! 	{
! 		int64 remainder;
! 		int64 oldval = value;
! 		/*
! 		 * division by constants can be optimized by some modern
! 		 * compilers (including gcc). We could add the concrete,
! 		 * optimized, calculatation here to be fast at -O0 and/or
! 		 * other compilers... Not sure if its worth doing.
! 		 */
! 		value /= 10;
! 		remainder = oldval - value * 10;
! 		*buf++ = '0' + remainder;
! 	}
! 	while (value != 0);
! 
! 	if (neg)
! 		*buf++ = '-';
! 
! 	/* have to reorder the string, but not 0 byte */
! 	*buf-- = 0;
! 
! 	/* reverse string */
! 	while (bufstart < buf)
! 	{
! 		char swap = *bufstart;
! 		*bufstart++ = *buf;
! 		*buf-- = swap;
! 	}
  }
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 020ce3c..7b1bb23 100644
*** a/src/include/utils/builtins.h
--- b/src/include/utils/builtins.h
*************** extern Datum current_schemas(PG_FUNCTION
*** 275,280 ****
--- 275,281 ----
  extern int32 pg_atoi(char *s, int size, int c);
  extern void pg_itoa(int16 i, char *a);
  extern void pg_ltoa(int32 l, char *a);
+ extern void pg_lltoa(int64 ll, char *a);
  
  /*
   *		Per-opclass comparison functions for new btrees.  These are
diff --git a/src/test/regress/expected/int2.out b/src/test/regress/expected/int2.out
index 8fff981..3bb26b3 100644
*** a/src/test/regress/expected/int2.out
--- b/src/test/regress/expected/int2.out
*************** SELECT '' AS five, i.f1, i.f1 / int4 '2'
*** 242,244 ****
--- 242,257 ----
        | -32767 | -16383
  (5 rows)
  
+ -- corner cases
+ SELECT (1<<15-1)::int2::text;
+  text  
+ -------
+  16384
+ (1 row)
+ 
+ SELECT (-1<<15)::int2::text;
+   text  
+ --------
+  -32768
+ (1 row)
+ 
diff --git a/src/test/regress/expected/int4.out b/src/test/regress/expected/int4.out
index 3fadb7b..42095c7 100644
*** a/src/test/regress/expected/int4.out
--- b/src/test/regress/expected/int4.out
*************** SELECT (2 + 2) / 2 AS two;
*** 329,331 ****
--- 329,344 ----
     2
  (1 row)
  
+ -- corner cases
+ SELECT (1<<31-1)::int4::text;
+     text    
+ ------------
+  1073741824
+ (1 row)
+ 
+ SELECT (1<<31)::int4::text;
+     text     
+ -------------
+  -2147483648
+ (1 row)
+ 
diff --git a/src/test/regress/expected/int8.out b/src/test/regress/expected/int8.out
index c8e2dad..e156067 100644
*** a/src/test/regress/expected/int8.out
--- b/src/test/regress/expected/int8.out
*************** SELECT * FROM generate_series('+45678901
*** 802,804 ****
--- 802,817 ----
   4567890123456799
  (6 rows)
  
+ -- corner cases
+ SELECT (1<<63-1)::int8::text;
+     text    
+ ------------
+  1073741824
+ (1 row)
+ 
+ SELECT (1<<63)::int8::text;
+     text     
+ -------------
+  -2147483648
+ (1 row)
+ 
diff --git a/src/test/regress/sql/int2.sql b/src/test/regress/sql/int2.sql
index 20d31b6..8bffe53 100644
*** a/src/test/regress/sql/int2.sql
--- b/src/test/regress/sql/int2.sql
*************** SELECT '' AS five, i.f1, i.f1 - int4 '2'
*** 83,85 ****
--- 83,89 ----
  SELECT '' AS five, i.f1, i.f1 / int2 '2' AS x FROM INT2_TBL i;
  
  SELECT '' AS five, i.f1, i.f1 / int4 '2' AS x FROM INT2_TBL i;
+ 
+ -- corner cases
+ SELECT (1<<15-1)::int2::text;
+ SELECT (-1<<15)::int2::text;
diff --git a/src/test/regress/sql/int4.sql b/src/test/regress/sql/int4.sql
index 5e84f64..39bfec1 100644
*** a/src/test/regress/sql/int4.sql
--- b/src/test/regress/sql/int4.sql
*************** SELECT 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1
*** 123,125 ****
--- 123,129 ----
  SELECT 2 + 2 / 2 AS three;
  
  SELECT (2 + 2) / 2 AS two;
+ 
+ -- corner cases
+ SELECT (1<<31-1)::int4::text;
+ SELECT (1<<31)::int4::text;
diff --git a/src/test/regress/sql/int8.sql b/src/test/regress/sql/int8.sql
index 648563c..7fff03c 100644
*** a/src/test/regress/sql/int8.sql
--- b/src/test/regress/sql/int8.sql
*************** SELECT q1, q1 << 2 AS "shl", q1 >> 3 AS
*** 190,192 ****
--- 190,196 ----
  SELECT * FROM generate_series('+4567890123456789'::int8, '+4567890123456799'::int8);
  SELECT * FROM generate_series('+4567890123456789'::int8, '+4567890123456799'::int8, 0);
  SELECT * FROM generate_series('+4567890123456789'::int8, '+4567890123456799'::int8, 2);
+ 
+ -- corner cases
+ SELECT (1<<63-1)::int8::text;
+ SELECT (1<<63)::int8::text;
-- 
1.7.3.rc1.5.g73aa2