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
28 use Test::More tests => @TestSizes * 2 # sort() tests
29 * 6 # number of pragmas to test
30 + 1 # extra test for qsort instability
31 + 3 # tests for sort::current
32 + 3; # tests for "defaults" and "no sort"
34 # Generate array of specified size for testing sort.
36 # We ensure repeated items, where possible, by drawing the $size items
37 # from a pool of size sqrt($size). Each randomly chosen item is
38 # tagged with the item index, so we can detect original input order,
39 # and reconstruct the original array order.
42 my $size = int(shift); # fractions not welcome
46 if ($size < 0) { $size = 0; } # avoid complexity with sqrt
47 elsif ($size > $BigEnough) { $size = $BigEnough; }
48 $#a = $size - 1; # preallocate array
49 $items = int(sqrt($size)); # number of distinct items
50 for ($i = 0; $i < $size; ++$i) {
51 $a[$i] = sprintf($ItemFormat, int($items * rand()), $i);
57 # Check for correct order (including stability)
61 my $status = ''; # so far, so good
64 for ($i = 0; $i < $#$aref; ++$i) {
65 # Equality shouldn't happen, but catch it in the contents check
66 next if ($aref->[$i] le $aref->[$i+1]);
67 $disorder = (substr($aref->[$i], 0, $RootWidth) eq
68 substr($aref->[$i+1], 0, $RootWidth)) ?
69 "Instability" : "Disorder";
70 # Keep checking if merely unstable... disorder is much worse.
72 "$disorder at element $i between $aref->[$i] and $aref->[$i+1]";
73 last unless ($disorder eq "Instability");
79 # Verify that the two array refs reference identical arrays
82 my ($aref, $bref) = @_;
86 if (@$aref != @$bref) {
87 $status = "Sizes differ: " . @$aref . " vs " . @$bref;
89 for ($i = 0; $i < @$aref; ++$i) {
90 next if ($aref->[$i] eq $bref->[$i]);
91 $status = "Element $i differs: $aref->[$i] vs $bref->[$i]";
99 # Test sort on arrays of various sizes (set up in @TestSizes)
102 my ($dothesort, $expect_unstable) = @_;
103 my ($ts, $unsorted, @sorted, $status);
104 my $unstable_num = 0;
106 foreach $ts (@TestSizes) {
107 $unsorted = genarray($ts);
108 # Sort only on item portion of each element.
109 # There will typically be many repeated items,
110 # and their order had better be preserved.
111 @sorted = $dothesort->(sub { substr($a, 0, $RootWidth)
113 substr($b, 0, $RootWidth) }, $unsorted);
114 $status = checkorder(\@sorted);
115 # Put the items back into the original order.
116 # The contents of the arrays had better be identical.
117 if ($expect_unstable && $status =~ /^Instability/) {
121 is($status, '', "order ok for size $ts");
122 @sorted = $dothesort->(sub { substr($a, $RootWidth)
124 substr($b, $RootWidth) }, \@sorted);
125 $status = checkequal(\@sorted, $unsorted);
126 is($status, '', "contents ok for size $ts");
128 # If the following test (#58) fails, see the comments in pp_sort.c
130 if ($expect_unstable) {
131 ok($unstable_num > 0, 'Instability ok');
135 # Test with no pragma still loaded -- stability expected (this is a mergesort)
136 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
140 my $sort_current; BEGIN { $sort_current = sort::current(); }
141 is($sort_current, 'quicksort', 'sort::current for _qsort');
142 main(sub { sort {&{$_[0]}} @{$_[1]} }, 1);
146 use sort qw(_mergesort);
147 my $sort_current; BEGIN { $sort_current = sort::current(); }
148 is($sort_current, 'mergesort', 'sort::current for _mergesort');
149 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
153 use sort qw(_qsort stable);
154 my $sort_current; BEGIN { $sort_current = sort::current(); }
155 is($sort_current, 'quicksort stable', 'sort::current for _qsort stable');
156 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
159 # Tests added to check "defaults" subpragma, and "no sort"
162 use sort qw(_qsort stable);
164 my $sort_current; BEGIN { $sort_current = sort::current(); }
165 is($sort_current, 'stable', 'sort::current after no _qsort');
166 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);
170 use sort qw(defaults _qsort);
171 my $sort_current; BEGIN { $sort_current = sort::current(); }
172 is($sort_current, 'quicksort', 'sort::current after defaults _qsort');
173 # Not expected to be stable, so don't test for stability here
177 use sort qw(defaults stable);
178 my $sort_current; BEGIN { $sort_current = sort::current(); }
179 is($sort_current, 'stable', 'sort::current after defaults stable');
180 main(sub { sort {&{$_[0]}} @{$_[1]} }, 0);