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Cross-platform Rust rewrite of the GNU coreutils
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factor only supports numbers up to 2^64 - 1 #1559

Open tdulcet opened 4 years ago

tdulcet commented 4 years ago

The current factor implementation only supports numbers up to 264 - 1. GNU factor supports numbers up to 2127 - 1 if compiled without the GNU Multiple Precision (GMP) library or arbitrary-precision numbers if compiled with it. This can be tested by running this command:

factor 9223372036854775807 18446744073709551615 170141183460469231731687303715884105727 340282366920938463463374607431768211455

which is factor 263 - 1, 264 - 1, 2127 - 1 and 2128 - 1.

GNU factor without GMP produces:

$ factor 9223372036854775807 18446744073709551615 170141183460469231731687303715884105727 340282366920938463463374607431768211455
9223372036854775807: 7 7 73 127 337 92737 649657
18446744073709551615: 3 5 17 257 641 65537 6700417
170141183460469231731687303715884105727: 170141183460469231731687303715884105727
factor: ‘340282366920938463463374607431768211455’ is too large

GNU factor with GMP produces:

$ factor 9223372036854775807 18446744073709551615 170141183460469231731687303715884105727 340282366920938463463374607431768211455
9223372036854775807: 7 7 73 127 337 92737 649657
18446744073709551615: 3 5 17 257 641 65537 6700417
170141183460469231731687303715884105727: 170141183460469231731687303715884105727
340282366920938463463374607431768211455: 3 5 17 257 641 65537 274177 6700417 67280421310721

and uutils' factor produces:

$ uu-factor 9223372036854775807 18446744073709551615 170141183460469231731687303715884105727 340282366920938463463374607431768211455
factor: warning: 170141183460469231731687303715884105727: number too large to fit in target type
factor: warning: 340282366920938463463374607431768211455: number too large to fit in target type
9223372036854775807: 7 7 73 127 337 60247241209
18446744073709551615: 3 5 17 257 641 65537 6700417

This was first posted in https://github.com/uutils/coreutils/issues/1456#issuecomment-647456945. Issue created at the request of @nbraud.

stale[bot] commented 3 years ago

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

stale[bot] commented 1 year ago

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

tdulcet commented 1 year ago

GNU factor supports numbers up to 2127 - 1 if compiled without the GNU Multiple Precision (GMP) library or arbitrary-precision numbers if compiled with it.

As of GNU Coreutils 9.0, it is no longer possible to compile GNU factor without the GMP library, which makes this issue even more important (source):

expr and factor now support bignums on all platforms.

The change was made in https://github.com/coreutils/coreutils/commit/13046444888a7e96f48d28fdd5a6ffe03d4ab036.