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Change float8-to-int8 conversion to round to nearest, rather than

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truncating to integer.  Remove regress test that checks whether
4567890123456789 can be converted to float without loss; since that's
52 bits, it's on the hairy edge of failing with IEEE float8s, and indeed
rint seems to give platform-dependent results for it.
This commit is contained in:
Tom Lane 2001-01-26 22:50:26 +00:00
parent 5a832218fd
commit b78d1bed07
4 changed files with 11 additions and 32 deletions
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22
src/backend/utils/adt/int8.c
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/int8.c,v 1.27 2001/01/24 19:43:14 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/int8.c,v 1.28 2001/01/26 22:50:26 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -693,13 +693,6 @@ i8tod(PG_FUNCTION_ARGS)
/* dtoi8()
* Convert double float to 8-byte integer.
* Do a range check before the conversion.
* Note that the comparison probably isn't quite right
* since we only have ~52 bits of precision in a double float
* and so subtracting one from a large number gives the large
* number exactly. However, for some reason the comparison below
* does the right thing on my i686/linux-rh4.2 box.
* - thomas 1998-06-16
*/
Datum
dtoi8(PG_FUNCTION_ARGS)
@ -707,11 +700,18 @@ dtoi8(PG_FUNCTION_ARGS)
float8 val = PG_GETARG_FLOAT8(0);
int64 result;
if ((val < (-pow(2.0, 63.0) + 1)) || (val > (pow(2.0, 63.0) - 1)))
elog(ERROR, "Floating point conversion to int64 is out of range");
/* Round val to nearest integer (but it's still in float form) */
val = rint(val);
/*
* Does it fit in an int64? Avoid assuming that we have handy constants
* defined for the range boundaries, instead test for overflow by
* reverse-conversion.
*/
result = (int64) val;
if ((float8) result != val)
elog(ERROR, "Floating point conversion to int8 is out of range");
PG_RETURN_INT64(result);
}

10
src/test/regress/expected/int8-exp-three-digits.out
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@ -87,16 +87,6 @@ SELECT '' AS five, q2, float8(q2) FROM INT8_TBL;
| -4567890123456789 | -4.56789012345679e+015
(5 rows)
SELECT '' AS five, q1, int8(float8(q1)) AS "two coercions" FROM INT8_TBL;
five | q1 | two coercions
------+------------------+------------------
| 123 | 123
| 123 | 123
| 4567890123456789 | 4567890123456789
| 4567890123456789 | 4567890123456789
| 4567890123456789 | 4567890123456789
(5 rows)
SELECT '' AS five, 2 * q1 AS "twice int4" FROM INT8_TBL;
five | twice int4
------+------------------

10
src/test/regress/expected/int8.out
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@ -87,16 +87,6 @@ SELECT '' AS five, q2, float8(q2) FROM INT8_TBL;
| -4567890123456789 | -4.56789012345679e+15
(5 rows)
SELECT '' AS five, q1, int8(float8(q1)) AS "two coercions" FROM INT8_TBL;
five | q1 | two coercions
------+------------------+------------------
| 123 | 123
| 123 | 123
| 4567890123456789 | 4567890123456789
| 4567890123456789 | 4567890123456789
| 4567890123456789 | 4567890123456789
(5 rows)
SELECT '' AS five, 2 * q1 AS "twice int4" FROM INT8_TBL;
five | twice int4
------+------------------

1
src/test/regress/sql/int8.sql
View File

@ -22,7 +22,6 @@ SELECT '' AS five, q1, q2, q1 / q2 AS divide FROM INT8_TBL;
SELECT '' AS five, q1, float8(q1) FROM INT8_TBL;
SELECT '' AS five, q2, float8(q2) FROM INT8_TBL;
SELECT '' AS five, q1, int8(float8(q1)) AS "two coercions" FROM INT8_TBL;
SELECT '' AS five, 2 * q1 AS "twice int4" FROM INT8_TBL;
SELECT '' AS five, q1 * 2 AS "twice int4" FROM INT8_TBL;