Commit | Line | Data |
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84d4ea48 JH |
1 | #!./perl |
2 | ||
be6228f7 RGS |
3 | # This tests the behavior of sort() under the different 'use sort' forms. |
4 | # Algorithm by John P. Linderman. | |
5 | ||
be6228f7 RGS |
6 | my ($BigWidth, $BigEnough, $RootWidth, $ItemFormat, @TestSizes, $WellSoaked); |
7 | ||
84d4ea48 JH |
8 | BEGIN { |
9 | chdir 't' if -d 't'; | |
be6228f7 RGS |
10 | @INC = qw(../lib); |
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 | |
22 | } | |
84d4ea48 JH |
23 | } |
24 | ||
be6bd645 AD |
25 | use strict; |
26 | use warnings; | |
27 | ||
be6228f7 RGS |
28 | use Test::More tests => @TestSizes * 2 # sort() tests |
29 | * 4 # number of pragmas to test | |
30 | + 1 # extra test for qsort instability | |
31 | + 3; # tests for sort::current | |
84d4ea48 | 32 | |
be6228f7 RGS |
33 | # Generate array of specified size for testing sort. |
34 | # | |
35 | # We ensure repeated items, where possible, by drawing the $size items | |
36 | # from a pool of size sqrt($size). Each randomly chosen item is | |
37 | # tagged with the item index, so we can detect original input order, | |
38 | # and reconstruct the original array order. | |
39 | ||
40 | sub genarray { | |
41 | my $size = int(shift); # fractions not welcome | |
42 | my ($items, $i); | |
43 | my @a; | |
44 | ||
45 | if ($size < 0) { $size = 0; } # avoid complexity with sqrt | |
46 | elsif ($size > $BigEnough) { $size = $BigEnough; } | |
47 | $#a = $size - 1; # preallocate array | |
48 | $items = int(sqrt($size)); # number of distinct items | |
49 | for ($i = 0; $i < $size; ++$i) { | |
50 | $a[$i] = sprintf($ItemFormat, int($items * rand()), $i); | |
51 | } | |
52 | return \@a; | |
53 | } | |
54 | ||
55 | ||
56 | # Check for correct order (including stability) | |
57 | ||
58 | sub checkorder { | |
59 | my $aref = shift; | |
60 | my $status = ''; # so far, so good | |
28e9118f | 61 | my ($i, $disorder); |
be6228f7 RGS |
62 | |
63 | for ($i = 0; $i < $#$aref; ++$i) { | |
28e9118f JL |
64 | # Equality shouldn't happen, but catch it in the contents check |
65 | next if ($aref->[$i] le $aref->[$i+1]); | |
66 | $disorder = (substr($aref->[$i], 0, $RootWidth) eq | |
67 | substr($aref->[$i+1], 0, $RootWidth)) ? | |
68 | "Instability" : "Disorder"; | |
69 | # Keep checking if merely unstable... disorder is much worse. | |
70 | $status = | |
71 | "$disorder at element $i between $aref->[$i] and $aref->[$i+1]"; | |
72 | last unless ($disorder eq "Instability"); | |
be6228f7 RGS |
73 | } |
74 | return $status; | |
75 | } | |
76 | ||
77 | ||
78 | # Verify that the two array refs reference identical arrays | |
79 | ||
80 | sub checkequal { | |
81 | my ($aref, $bref) = @_; | |
82 | my $status = ''; | |
83 | my $i; | |
84 | ||
85 | if (@$aref != @$bref) { | |
86 | $status = "Sizes differ: " . @$aref . " vs " . @$bref; | |
87 | } else { | |
88 | for ($i = 0; $i < @$aref; ++$i) { | |
89 | next if ($aref->[$i] eq $bref->[$i]); | |
90 | $status = "Element $i differs: $aref->[$i] vs $bref->[$i]"; | |
91 | last; | |
92 | } | |
93 | } | |
94 | return $status; | |
95 | } | |
96 | ||
97 | ||
98 | # Test sort on arrays of various sizes (set up in @TestSizes) | |
99 | ||
100 | sub main { | |
101 | my ($expect_unstable) = @_; | |
102 | my ($ts, $unsorted, @sorted, $status); | |
103 | my $unstable_num = 0; | |
104 | ||
105 | foreach $ts (@TestSizes) { | |
106 | $unsorted = genarray($ts); | |
107 | # Sort only on item portion of each element. | |
108 | # There will typically be many repeated items, | |
109 | # and their order had better be preserved. | |
110 | @sorted = sort { substr($a, 0, $RootWidth) | |
111 | cmp | |
112 | substr($b, 0, $RootWidth) } @$unsorted; | |
113 | $status = checkorder(\@sorted); | |
114 | # Put the items back into the original order. | |
115 | # The contents of the arrays had better be identical. | |
116 | if ($expect_unstable && $status =~ /^Instability/) { | |
117 | $status = ''; | |
118 | ++$unstable_num; | |
119 | } | |
120 | is($status, '', "order ok for size $ts"); | |
121 | @sorted = sort { substr($a, $RootWidth) | |
122 | cmp | |
123 | substr($b, $RootWidth) } @sorted; | |
124 | $status = checkequal(\@sorted, $unsorted); | |
125 | is($status, '', "contents ok for size $ts"); | |
126 | } | |
78210658 AD |
127 | # If the following test (#58) fails, see the comments in pp_sort.c |
128 | # for Perl_sortsv(). | |
be6228f7 RGS |
129 | if ($expect_unstable) { |
130 | ok($unstable_num > 0, 'Instability ok'); | |
131 | } | |
84d4ea48 JH |
132 | } |
133 | ||
be6228f7 RGS |
134 | # Test with no pragma still loaded -- stability expected (this is a mergesort) |
135 | main(0); | |
136 | ||
137 | # XXX We're using this eval "..." trick to force recompilation, | |
138 | # to ensure that the correct pragma is enabled when main() is run. | |
045ac317 RGS |
139 | # Currently 'use sort' modifies $sort::hints at compile-time, but |
140 | # pp_sort() fetches its value at run-time. | |
be6228f7 RGS |
141 | # The order of those evals is important. |
142 | ||
143 | eval q{ | |
144 | use sort qw(_qsort); | |
145 | is(sort::current(), 'quicksort', 'sort::current for _qsort'); | |
146 | main(1); | |
147 | }; | |
148 | die $@ if $@; | |
149 | ||
150 | eval q{ | |
151 | use sort qw(_mergesort); | |
152 | is(sort::current(), 'mergesort', 'sort::current for _mergesort'); | |
153 | main(0); | |
154 | }; | |
155 | die $@ if $@; | |
84d4ea48 | 156 | |
be6228f7 RGS |
157 | eval q{ |
158 | use sort qw(_qsort stable); | |
159 | is(sort::current(), 'quicksort stable', 'sort::current for _qsort stable'); | |
160 | main(0); | |
161 | }; | |
162 | die $@ if $@; |