busybox/testsuite/factor.tests
Denys Vlasenko 6452c30036 factor: detect squares
If we have a square, the speedup can be extremely large
(in best case example below, it's ~40000 times faster):

$ time ./busybox_old factor 18446743988964486098
18446743988964486098: 2 3037000493 3037000493
real	0m4.246s
$ time ./busybox factor 18446743988964486098
18446743988964486098: 2 3037000493 3037000493
real	0m0.000s

function                                             old     new   delta
isqrt_odd                                              -      57     +57
print_w                                                -      36     +36
factorize                                            218     236     +18
print_h                                                -       7      +7
factorize_numstr                                      65      72      +7
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 2/0 up/down: 125/0)             Total: 125 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2020-12-22 20:24:30 +01:00

72 lines
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#!/bin/sh
# Copyright 2017 by Denys Vlasenko <vda.linux@googlemail.com>
# Licensed under GPLv2, see file LICENSE in this source tree.
. ./testing.sh
# testing "test name" "command" "expected result" "file input" "stdin"
# file input will be file called "input"
# test can create a file "actual" instead of writing to stdout
testing "factor ' 0'" \
"factor ' 0'" \
"0:\n" \
"" ""
testing "factor +1" \
"factor +1" \
"1:\n" \
"" ""
testing "factor ' +2'" \
"factor ' +2'" \
"2: 2\n" \
"" ""
testing "factor 1024" \
"factor 1024" \
"1024: 2 2 2 2 2 2 2 2 2 2\n" \
"" ""
testing "factor 2^61-1" \
"factor 2305843009213693951" \
"2305843009213693951: 2305843009213693951\n" \
"" ""
testing "factor 2^62-1" \
"factor 4611686018427387903" \
"4611686018427387903: 3 715827883 2147483647\n" \
"" ""
testing "factor 2^64-1" \
"factor 18446744073709551615" \
"18446744073709551615: 3 5 17 257 641 65537 6700417\n" \
"" ""
# This is a 60-bit number (0x888 86ff db34 4692): first few primes multiplied together:
testing "factor \$((2*3*5*7*11*13*17*19*23*29*31*37*41*43*47))" \
"factor \$((2*3*5*7*11*13*17*19*23*29*31*37*41*43*47))" \
"614889782588491410: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47\n" \
"" ""
# Test that square-detection code is not buggy
testing "factor 2 * 3037000493 * 3037000493" \
"factor 18446743988964486098" \
"18446743988964486098: 2 3037000493 3037000493\n" \
"" ""
testing "factor 3 * 2479700513 * 2479700513" \
"factor 18446743902517389507" \
"18446743902517389507: 3 2479700513 2479700513\n" \
"" ""
# including square-of-square cases:
testing "factor 3 * 37831 * 37831 * 37831 * 37831" \
"factor 6144867742934288163" \
"6144867742934288163: 3 37831 37831 37831 37831\n" \
"" ""
testing "factor 3 * 13^16" \
"factor 1996249827549539523" \
"1996249827549539523: 3 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13\n" \
"" ""
testing "factor 13^16" \
"factor 665416609183179841" \
"665416609183179841: 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13\n" \
"" ""
exit $FAILCOUNT