3 # This tests the behavior of sort() under the different 'use sort' forms.
4 # Algorithm by John P. Linderman.
6 my ($BigWidth, $BigEnough, $RootWidth, $ItemFormat, @TestSizes, $WellSoaked);
11 $BigWidth = 6; # Digits in $BigEnough-1
12 $BigEnough = 10**$BigWidth; # Largest array we'll attempt
13 $RootWidth = int(($BigWidth+1)/2); # Digits in sqrt($BigEnough-1)
14 $ItemFormat = "%0${RootWidth}d%0${BigWidth}d"; # Array item format
15 @TestSizes = (0, 1, 2); # Small special cases
16 # Testing all the way up to $BigEnough takes too long
17 # for casual testing. There are some cutoffs (~256)
18 # in pp_sort that should be tested, but 10_000 is ample.
19 $WellSoaked = 10_000; # <= $BigEnough
20 for (my $ts = 3; $ts < $WellSoaked; $ts *= 10**(1/3)) {
21 push(@TestSizes, int($ts)); # about 3 per decade
30 # Generate array of specified size for testing sort.
32 # We ensure repeated items, where possible, by drawing the $size items
33 # from a pool of size sqrt($size). Each randomly chosen item is
34 # tagged with the item index, so we can detect original input order,
35 # and reconstruct the original array order.
38 my $size = int(shift); # fractions not welcome
42 if ($size < 0) { $size = 0; } # avoid complexity with sqrt
43 elsif ($size > $BigEnough) { $size = $BigEnough; }
44 $#a = $size - 1; # preallocate array
45 $items = int(sqrt($size)); # number of distinct items
46 for ($i = 0; $i < $size; ++$i) {
47 $a[$i] = sprintf($ItemFormat, int($items * rand()), $i);
53 # Check for correct order (including stability)
57 my $status = ''; # so far, so good
60 for ($i = 0; $i < $#$aref; ++$i) {
61 # Equality shouldn't happen, but catch it in the contents check
62 next if ($aref->[$i] le $aref->[$i+1]);
63 $disorder = (substr($aref->[$i], 0, $RootWidth) eq
64 substr($aref->[$i+1], 0, $RootWidth)) ?
65 "Instability" : "Disorder";
66 # Keep checking if merely unstable... disorder is much worse.
68 "$disorder at element $i between $aref->[$i] and $aref->[$i+1]";
69 last unless ($disorder eq "Instability");
75 # Verify that the two array refs reference identical arrays
78 my ($aref, $bref) = @_;
82 if (@$aref != @$bref) {
83 $status = "Sizes differ: " . @$aref . " vs " . @$bref;
85 for ($i = 0; $i < @$aref; ++$i) {
86 next if ($aref->[$i] eq $bref->[$i]);
87 $status = "Element $i differs: $aref->[$i] vs $bref->[$i]";
95 # Test sort on arrays of various sizes (set up in @TestSizes)
98 my ($dothesort, $expect_unstable) = @_;
99 my ($ts, $unsorted, @sorted, $status);
100 my $unstable_num = 0;
102 foreach $ts (@TestSizes) {
103 $unsorted = genarray($ts);
104 # Sort only on item portion of each element.
105 # There will typically be many repeated items,
106 # and their order had better be preserved.
107 @sorted = $dothesort->(sub { substr($a, 0, $RootWidth)
109 substr($b, 0, $RootWidth) }, $unsorted);
110 $status = checkorder(\@sorted);
111 # Put the items back into the original order.
112 # The contents of the arrays had better be identical.
113 if ($expect_unstable && $status =~ /^Instability/) {
117 is($status, '', "order ok for size $ts");
118 @sorted = $dothesort->(sub { substr($a, $RootWidth)
120 substr($b, $RootWidth) }, \@sorted);
121 $status = checkequal(\@sorted, $unsorted);
122 is($status, '', "contents ok for size $ts");
124 if ($expect_unstable) {
125 ok($unstable_num > 0, 'Instability ok');
129 # Test with no pragma yet loaded. Stability is expected from default sort.
130 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
132 # Verify that we have eliminated the segfault that could be triggered
133 # by invoking a sort as part of a comparison routine.
134 # No need for an explicit test. If we don't segfault, we're good.
139 use sort qw( defaults stable );
140 my @ignore = sort (5,4,3,2,1);
143 use sort qw( defaults stable );
144 my @nested = sort { dumbsort($a,$b) } (3,2,2,1);
152 local $SIG{__WARN__} = sub {$a = $_[0]};
153 $sort_current = sort::current();
154 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns");
156 is($sort_current, 'stable', 'sort::current for stable');
157 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
160 # Tests added to check "defaults" subpragma, and "no sort"
163 use sort qw(defaults stable);
167 local $SIG{__WARN__} = sub {$a = $_[0]};
168 $sort_current = sort::current();
169 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns");
171 is($sort_current, 'stable', 'sort::current after defaults stable');
172 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
175 # Tests added to check how sort::current is deprecated
182 local $SIG{__WARN__} = sub {$a = $_[0]};
183 $sort_current = sort::current();
184 like($a, qr/\Asort::current is deprecated\b/, "sort::current warns");
186 is($sort_current, 'stable', 'sort::current *always* stable');
190 use sort qw(defaults);
193 no warnings qw(deprecated);
195 local $SIG{__WARN__} = sub {$a = $_[0]};
196 $sort_current = sort::current();
197 is($a, "", "sort::current warning can be disabled");
199 is($sort_current, 'stable', 'sort::current *always* stable');
206 no warnings qw(deprecated);
208 local $SIG{__WARN__} = sub {$a = $_[0]};
209 $sort_current = sort::current();
210 is($a, "", "sort::current warning can be disabled");
212 is($sort_current, 'stable', 'sort::current for stable');