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GCD does not work properly on big integers (> PHP_INT_MAX) #2

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roadster31 opened this issue Oct 27, 2015 · 1 comment

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roadster31 commented Oct 27, 2015

GCG::getGCD() uses is_int() to check if a number is an integer, but this function returns false if this number is greater than PHP_INT_MAX.

roadster31 mentioned this issue

Fixed is_int() problem #3

Merged

gillesbourgeat closed this as completed

roadster31 reopened this

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roadster31 commented Nov 8, 2018

I'm reopening this issue, as the modulo (%) operator is casting its operands to integers, which may cause overflow if operands are > PHP_INT_MAX.

Example on a 32 bit machine, where PHP_INT_MAX = 2147483647 :

16748050000 % 1148700 =-1056684 ! (the proper result is 4000)

Using fmod() (floating point modulo) is not a proper solution, as floating point may cause a lost of precision on large numbers.

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