custom-int248-string-conversion-routines.patch

diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index 894110d..abf4d57 100644
--- a/src/backend/utils/adt/int8.c
+++ b/src/backend/utils/adt/int8.c
@@ -20,6 +20,7 @@
 #include "funcapi.h"
 #include "libpq/pqformat.h"
 #include "utils/int8.h"
+#include "utils/builtins.h"
 
 
 #define MAXINT8LEN		25
@@ -158,12 +159,9 @@ 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");
-
+	pg_lltoa(val, buf);
 	result = pstrdup(buf);
 	PG_RETURN_CSTRING(result);
 }
diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c
index 5f8083f..792b248 100644
--- a/src/backend/utils/adt/numutils.c
+++ b/src/backend/utils/adt/numutils.c
@@ -3,8 +3,6 @@
  * 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
  *
@@ -109,27 +107,126 @@ pg_atoi(char *s, int size, int c)
 }
 
 /*
- *		pg_itoa			- converts a short int to its string represention
+ * pg_ltoa - convert a signed 16bit integer to a string representation
  *
- *		Note:
- *				previously based on ~ingres/source/gutil/atoi.c
- *				now uses vendor's sprintf conversion
+ * It doesnt seem worth implementing this separately.
  */
 void
 pg_itoa(int16 i, char *a)
 {
-	sprintf(a, "%hd", (short) i);
+	pg_ltoa((int32)i, a);
 }
 
+
 /*
- *		pg_ltoa			- converts a long int to its string represention
+ * pg_ltoa - convert a signed 32bit integer to a string representation
  *
- *		Note:
- *				previously based on ~ingres/source/gutil/atoi.c
- *				now uses vendor's sprintf conversion
+ * 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 l, char *a)
-{
-	sprintf(a, "%d", l);
+pg_ltoa(int32 value, char *buf){
+	char *bufstart = buf;
+	bool neg = false;
+
+	/*
+	 * Avoid problems with the most negative not being representable
+	 * as a positive number
+	 */
+	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 a string representation
+ */
+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 number
+	 */
+	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 f4b2a96..8ec5d69 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -275,6 +275,7 @@ extern Datum current_schemas(PG_FUNCTION_ARGS);
 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
@@ -242,3 +242,16 @@ SELECT '' AS five, i.f1, i.f1 / int4 '2' AS x FROM INT2_TBL i;
       | -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
@@ -329,3 +329,16 @@ SELECT (2 + 2) / 2 AS two;
    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
@@ -802,3 +802,16 @@ SELECT * FROM generate_series('+4567890123456789'::int8, '+4567890123456799'::in
  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
@@ -83,3 +83,7 @@ SELECT '' AS five, i.f1, i.f1 - int4 '2' AS x FROM INT2_TBL i;
 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
@@ -123,3 +123,7 @@ SELECT 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 AS ten;
 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
@@ -190,3 +190,7 @@ SELECT q1, q1 << 2 AS "shl", q1 >> 3 AS "shr" FROM INT8_TBL;
 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;