#!perl
use strict;
my $count = 128;
plan(($^O eq 'os390') ? (skip_all => 'takes too long on os390')
: (tests => $count*4));
use Math::BigInt only => 'FastCalc';
my $length = 128;
# If you get a failure here, please re-run the test with the printed seed
# value as input "perl t/mbi_rand.t seed" and send me the output
my $seed = @ARGV == 1 ? $ARGV[0] : int(rand(1165537));
#diag(" seed: $seed\n");
srand($seed);
my $_base_len;
my @_base_len;
#diag(" lib: ", Math::BigInt->config('lib'));
if (Math::BigInt->config('lib') =~ /::Calc/) {
$_base_len = Math::BigInt::Calc->_base_len();
@_base_len = Math::BigInt::Calc->_base_len();
#diag("base len: $_base_len (scalar context)");
#diag("base len: @_base_len (list contex)");
}
my ($A, $B, $A_str, $B_str, $AdivB, $AmodB, $A_len, $B_len);
my $two = Math::BigInt->new(2);
for (my $i = 0; $i < $count; $i++) {
#diag("");
# length of A and B
$A_len = int(rand($length) + 1);
$B_len = int(rand($length) + 1);
$A_str = '';
$B_str = '';
# We create the numbers from "patterns", e.g. get a random number and a
# random count and string them together. This means things like
# "100000999999999999911122222222" are much more likely. If we just strung
# together digits, we would end up with "1272398823211223" etc. It also
# means that we get more frequently equal numbers or other special cases.
while (length($A_str) < $A_len) {
$A_str .= int(rand(100)) x int(rand(16));
}
while (length($B_str) < $B_len) {
$B_str .= int(rand(100)) x int(rand(16));
}
$A_str =~ s/^0+(?=\d)//;
$B_str =~ s/^0+(?=\d)//;
#diag(" As: $A_str");
#diag(" Bs: $B_str");
$A = Math::BigInt->new($A_str);
$B = Math::BigInt->new($B_str);
#diag(" A: $A");
#diag(" B: $B");
SKIP: {
skip '$A and/or $B are zero.', 4 if $A->is_zero() || $B->is_zero();
# check that int(A / B) * B + A % B == A holds for all inputs
# $X = ($A / $B) * $B + 2 * ($A % $B) - ($A % $B);
($AdivB, $AmodB) = $A->copy()->bdiv($B);
#diag(" A / B: $AdivB");
#diag(" A % B: $AmodB");
is($AdivB * $B + $two * $AmodB - $AmodB, $A_str,
"AdivB * B + 2 * AmodB - AmodB == A");
if (is($AdivB * $B / $B, $AdivB, "AdivB * B / B == AdivB")) {
if (Math::BigInt->config('lib') =~ /::Calc/) {
#diag("AdivB->[-1]: ", $AdivB->{value}->[-1]);
#diag(" B->[-1]: ", $B->{value}->[-1]);
}
}
# swap 'em and try this, too
# $X = ($B/$A)*$A + $B % $A;
($AdivB, $AmodB) = $B->copy()->bdiv($A);
# print "check: $AdivB $AmodB";
is($AdivB * $A + $two * $AmodB - $AmodB, $B_str,
"AdivB * A + 2 * AmodB - AmodB == B");
is($AdivB * $A / $A, $AdivB, "AdivB * A / A == AdivB");
}
}