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Fix GH-12143: Improved handling of adjusting result digits #12162

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Fix GH-12143: Improved handling of adjusting result digits #12162

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10aa082
Improved handling of adjusting result digits
SakiTakamachi Sep 9, 2023
ff7ee2d
stopped using for to generate floating point numbers and wrote everyt…
SakiTakamachi Sep 9, 2023
20411f6
fix to use var_dump instead of echo
SakiTakamachi Sep 10, 2023
c1e97cf
Added some test cases
SakiTakamachi Sep 15, 2023
bcf01cf
fix pre round comment
SakiTakamachi Sep 16, 2023
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6 changes: 3 additions & 3 deletions ext/standard/math.c
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Original file line number Diff line number Diff line change
Expand Up @@ -184,7 +184,7 @@ PHPAPI double _php_math_round(double value, int places, int mode) {

/* If the decimal precision guaranteed by FP arithmetic is higher than
the requested places BUT is small enough to make sure a non-zero value
is returned, pre-round the result to the precision */
is returned, adjust result digits to the precision */
if (precision_places > places && precision_places - 15 < places) {
int64_t use_precision = precision_places < INT_MIN+1 ? INT_MIN+1 : precision_places;

Expand All @@ -194,9 +194,9 @@ PHPAPI double _php_math_round(double value, int places, int mode) {
} else {
tmp_value = value / f2;
}
/* preround the result (tmp_value will always be something * 1e14,
/* adjust result digits (tmp_value will always be something * 1e14,
thus never larger than 1e15 here) */
tmp_value = php_round_helper(tmp_value, mode);
tmp_value = (tmp_value >= 0.0) ? floor(tmp_value) : ceil(tmp_value);

use_precision = places - precision_places;
use_precision = use_precision < INT_MIN+1 ? INT_MIN+1 : use_precision;
Expand Down
74 changes: 60 additions & 14 deletions ext/standard/tests/math/bug24142.phpt
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Expand Up @@ -2,19 +2,65 @@
Bug #24142 (round() problems)
--FILE--
<?php
$v = 0.005;
for ($i = 1; $i < 10; $i++) {
echo "round({$v}, 2) -> ".round($v, 2)."\n";
$v += 0.01;
}
echo "round(0.005, 2)\n";
var_dump(round(0.005, 2));
echo "\n";

echo "round(0.015, 2)\n";
var_dump(round(0.015, 2));
echo "\n";

echo "round(0.025, 2)\n";
var_dump(round(0.025, 2));
echo "\n";

echo "round(0.035, 2)\n";
var_dump(round(0.035, 2));
echo "\n";

echo "round(0.045, 2)\n";
var_dump(round(0.045, 2));
echo "\n";

echo "round(0.055, 2)\n";
var_dump(round(0.055, 2));
echo "\n";

echo "round(0.065, 2)\n";
var_dump(round(0.065, 2));
echo "\n";

echo "round(0.075, 2)\n";
var_dump(round(0.075, 2));
echo "\n";

echo "round(0.085, 2)\n";
var_dump(round(0.085, 2));
?>
--EXPECT--
round(0.005, 2) -> 0.01
round(0.015, 2) -> 0.02
round(0.025, 2) -> 0.03
round(0.035, 2) -> 0.04
round(0.045, 2) -> 0.05
round(0.055, 2) -> 0.06
round(0.065, 2) -> 0.07
round(0.075, 2) -> 0.08
round(0.085, 2) -> 0.09
round(0.005, 2)
float(0.01)

round(0.015, 2)
float(0.02)

round(0.025, 2)
float(0.03)

round(0.035, 2)
float(0.04)

round(0.045, 2)
float(0.05)

round(0.055, 2)
float(0.06)

round(0.065, 2)
float(0.07)

round(0.075, 2)
float(0.08)

round(0.085, 2)
float(0.09)
55 changes: 55 additions & 0 deletions ext/standard/tests/math/round_gh12143_adjustment_result_digit.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,55 @@
--TEST--
Fix GH-12143: Improved handling of adjusting result digits
--FILE--
<?php
echo "HALF_UP\n";
var_dump(round(1.700000000000145, 13, PHP_ROUND_HALF_UP));
var_dump(round(-1.700000000000145, 13, PHP_ROUND_HALF_UP));
Comment on lines +6 to +7
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could you maybe add more tests to cover more large number test cases and different rounding modes.

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Ideally at least the three numbers in the title of the original issue would explicitly be tested for all rounding modes:

#12143

var_dump(round(123456789012344.5, -1, PHP_ROUND_HALF_UP));
var_dump(round(-123456789012344.5, -1, PHP_ROUND_HALF_UP));
echo "\n";

echo "HALF_DOWN\n";
var_dump(round(1.700000000000156, 13, PHP_ROUND_HALF_DOWN));
var_dump(round(-1.700000000000156, 13, PHP_ROUND_HALF_DOWN));
var_dump(round(123456789012345.6, -1, PHP_ROUND_HALF_DOWN));
var_dump(round(-123456789012345.7, -1, PHP_ROUND_HALF_DOWN));
echo "\n";

echo "HALF_EVEN\n";
var_dump(round(1.700000000000255, 13, PHP_ROUND_HALF_EVEN));
var_dump(round(-1.700000000000255, 13, PHP_ROUND_HALF_EVEN));
var_dump(round(12345678901234.55, 0, PHP_ROUND_HALF_EVEN));
var_dump(round(-12345678901234.55, 0, PHP_ROUND_HALF_EVEN));
echo "\n";

echo "HALF_ODD\n";
var_dump(round(1.700000000000756, 13, PHP_ROUND_HALF_ODD));
var_dump(round(-1.700000000000757, 13, PHP_ROUND_HALF_ODD));
var_dump(round(12345678901233.56, 0, PHP_ROUND_HALF_ODD));
var_dump(round(-12345678901233.56, 0, PHP_ROUND_HALF_ODD));
?>
--EXPECT--
HALF_UP
float(1.7000000000001)
float(-1.7000000000001)
float(123456789012340)
float(-123456789012340)

HALF_DOWN
float(1.7000000000001)
float(-1.7000000000001)
float(123456789012340)
float(-123456789012340)

HALF_EVEN
float(1.7000000000002)
float(-1.7000000000002)
float(12345678901234)
float(-12345678901234)

HALF_ODD
float(1.7000000000007)
float(-1.7000000000007)
float(12345678901233)
float(-12345678901233)