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number_format: float within range of int can be cast to int … #12333

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number_format: float within range of int can be cast to int … #12333

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428dadb
number_format: float within range of int can be cast to int before ro…
marc-mabe Sep 30, 2023
36a2597
Fixed double value within long check
marc-mabe Sep 30, 2023
e977892
cast on 2^52
marc-mabe Oct 2, 2023
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10 changes: 10 additions & 0 deletions ext/standard/math.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1328,6 +1328,16 @@ PHP_FUNCTION(number_format)
break;

case IS_DOUBLE:
// double values of >= 2^52 can not have fractional digits anymore
// Casting to long on 64bit will not loose precision on rounding
if (UNEXPECTED(
(Z_DVAL_P(num) >= 4503599627370496.0 || Z_DVAL_P(num) <= -4503599627370496.0)
&& ZEND_DOUBLE_FITS_LONG(Z_DVAL_P(num))
Comment on lines +1334 to +1335
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Isn't ZEND_DOUBLE_FITS_LONG(Z_DVAL_P(num)) a little bit faster than the first condition? We have the difference of one execution of Z_DVAL_P.

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I don't think so.

  1. This is first checking the unusual case for numbers above 2^52
  2. ZEND_DOUBLE_FITS_LONG will cast ZEND_LONG_[MIN|MAX] and compare double values as well !((d) >= (double)ZEND_LONG_MAX || (d) < (double)ZEND_LONG_MIN)
  3. Z_DVAL_P(num) results in *num.value.dval

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For number outside the order doesn't matter because two conditions must be met. But for number inside the range the second condition has only one Z_DVAL_P evaluation and first condition has two of them. The comparison of doubles occurs in both conditions.

However, I think that the difference is so small that you can ignore my comment. Probably even it may be optimized by compiler.

)) {
RETURN_STR(_php_math_number_format_long((zend_long)Z_DVAL_P(num), dec, dec_point, dec_point_len, thousand_sep, thousand_sep_len));
break;
}

if (dec >= 0) {
dec_int = ZEND_LONG_INT_OVFL(dec) ? INT_MAX : (int)dec;
} else {
Expand Down
38 changes: 31 additions & 7 deletions ext/standard/tests/math/number_format_basiclong_64bit.phpt
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Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,12 @@ define("MAX_32Bit", 2147483647);
define("MIN_64Bit", -9223372036854775807 - 1);
define("MIN_32Bit", -2147483647 - 1);

$longVals = array(
$numbers = array(
MAX_64Bit, MIN_64Bit, MAX_32Bit, MIN_32Bit, MAX_64Bit - MAX_32Bit, MIN_64Bit - MIN_32Bit,
MAX_32Bit + 1, MIN_32Bit - 1, MAX_32Bit * 2, (MAX_32Bit * 2) + 1, (MAX_32Bit * 2) - 1,
MAX_64Bit -1, MAX_64Bit + 1, MIN_64Bit + 1, MIN_64Bit - 1
MAX_64Bit - 1, MAX_64Bit + 1, MIN_64Bit + 1, MIN_64Bit - 1,
// floats rounded as int
MAX_64Bit - 1024.0, MIN_64Bit + 1024.0
);

$precisions = array(
Expand All @@ -31,12 +33,12 @@ $precisions = array(
PHP_INT_MIN,
);

foreach ($longVals as $longVal) {
foreach ($numbers as $number) {
echo "--- testing: ";
var_dump($longVal);
var_dump($number);
foreach ($precisions as $precision) {
echo "... with precision " . $precision . ": ";
var_dump(number_format($longVal, $precision));
var_dump(number_format($number, $precision));
}
}

Expand Down Expand Up @@ -199,8 +201,30 @@ foreach ($longVals as $longVal) {
--- testing: float(-9.223372036854776E+18)
... with precision 5: string(32) "-9,223,372,036,854,775,808.00000"
... with precision 0: string(26) "-9,223,372,036,854,775,808"
... with precision -1: string(26) "-9,223,372,036,854,775,808"
... with precision -5: string(26) "-9,223,372,036,854,800,384"
... with precision -1: string(26) "-9,223,372,036,854,775,810"
... with precision -5: string(26) "-9,223,372,036,854,800,000"
... with precision -10: string(26) "-9,223,372,040,000,000,000"
... with precision -11: string(26) "-9,223,372,000,000,000,000"
... with precision -17: string(26) "-9,200,000,000,000,000,000"
... with precision -19: string(27) "-10,000,000,000,000,000,000"
... with precision -20: string(1) "0"
... with precision -9223372036854775808: string(1) "0"
--- testing: float(9.223372036854775E+18)
... with precision 5: string(31) "9,223,372,036,854,774,784.00000"
... with precision 0: string(25) "9,223,372,036,854,774,784"
... with precision -1: string(25) "9,223,372,036,854,774,780"
... with precision -5: string(25) "9,223,372,036,854,800,000"
... with precision -10: string(25) "9,223,372,040,000,000,000"
... with precision -11: string(25) "9,223,372,000,000,000,000"
... with precision -17: string(25) "9,200,000,000,000,000,000"
... with precision -19: string(26) "10,000,000,000,000,000,000"
... with precision -20: string(1) "0"
... with precision -9223372036854775808: string(1) "0"
--- testing: float(-9.223372036854775E+18)
... with precision 5: string(32) "-9,223,372,036,854,774,784.00000"
... with precision 0: string(26) "-9,223,372,036,854,774,784"
... with precision -1: string(26) "-9,223,372,036,854,774,780"
... with precision -5: string(26) "-9,223,372,036,854,800,000"
... with precision -10: string(26) "-9,223,372,040,000,000,000"
... with precision -11: string(26) "-9,223,372,000,000,000,000"
... with precision -17: string(26) "-9,200,000,000,000,000,000"
Expand Down