#!./perl -w
require './test.pl';
use strict;
# Tests of post/pre - increment/decrement operators.
# Verify that addition/subtraction properly upgrade to doubles.
# These tests are only significant on machines with 32 bit longs,
# and two's complement negation, but shouldn't fail anywhere.
my $a = 2147483647;
my $c=$a++;
cmp_ok($a, '==', 2147483648, "postincrement properly upgrades to double");
$a = 2147483647;
$c=++$a;
cmp_ok($a, '==', 2147483648, "preincrement properly upgrades to double");
$a = 2147483647;
$a=$a+1;
cmp_ok($a, '==', 2147483648, "addition properly upgrades to double");
$a = -2147483648;
$c=$a--;
cmp_ok($a, '==', -2147483649, "postdecrement properly upgrades to double");
$a = -2147483648;
$c=--$a;
cmp_ok($a, '==', -2147483649, "predecrement properly upgrades to double");
$a = -2147483648;
$a=$a-1;
cmp_ok($a, '==', -2147483649, "subtraction properly upgrades to double");
$a = 2147483648;
$a = -$a;
$c=$a--;
cmp_ok($a, '==', -2147483649,
"negation and postdecrement properly upgrade to double");
$a = 2147483648;
$a = -$a;
$c=--$a;
cmp_ok($a, '==', -2147483649,
"negation and predecrement properly upgrade to double");
$a = 2147483648;
$a = -$a;
$a=$a-1;
cmp_ok($a, '==', -2147483649,
"negation and subtraction properly upgrade to double");
$a = 2147483648;
$b = -$a;
$c=$b--;
cmp_ok($b, '==', -$a-1, "negation, postdecrement and additional negation");
$a = 2147483648;
$b = -$a;
$c=--$b;
cmp_ok($b, '==', -$a-1, "negation, predecrement and additional negation");
$a = 2147483648;
$b = -$a;
$b=$b-1;
cmp_ok($b, '==', -(++$a),
"negation, subtraction, preincrement and additional negation");
$a = undef;
is($a++, '0', "postinc undef returns '0'");
$a = undef;
is($a--, undef, "postdec undef returns undef");
# Verify that shared hash keys become unshared.
sub check_same {
my ($orig, $suspect) = @_;
my $fail;
while (my ($key, $value) = each %$suspect) {
if (exists $orig->{$key}) {
if ($orig->{$key} ne $value) {
print "# key '$key' was '$orig->{$key}' now '$value'\n";
$fail = 1;
}
} else {
print "# key '$key' is '$orig->{$key}', unexpect.\n";
$fail = 1;
}
}
foreach (keys %$orig) {
next if (exists $suspect->{$_});
print "# key '$_' was '$orig->{$_}' now missing\n";
$fail = 1;
}
ok (!$fail, "original hashes unchanged");
}
my (%orig) = my (%inc) = my (%dec) = my (%postinc) = my (%postdec)
= (1 => 1, ab => "ab");
my %up = (1=>2, ab => 'ac');
my %down = (1=>0, ab => -1);
foreach (keys %inc) {
my $ans = $up{$_};
my $up;
eval {$up = ++$_};
is($up, $ans, "key '$_' incremented correctly");
is($@, '', "no error condition");
}
check_same (\%orig, \%inc);
foreach (keys %dec) {
my $ans = $down{$_};
my $down;
eval {$down = --$_};
is($down, $ans, "key '$_' decremented correctly");
is($@, '', "no error condition");
}
check_same (\%orig, \%dec);
foreach (keys %postinc) {
my $ans = $postinc{$_};
my $up;
eval {$up = $_++};
is($up, $ans, "assignment preceded postincrement");
is($@, '', "no error condition");
}
check_same (\%orig, \%postinc);
foreach (keys %postdec) {
my $ans = $postdec{$_};
my $down;
eval {$down = $_--};
is($down, $ans, "assignment preceded postdecrement");
is($@, '', "no error condition");
}
check_same (\%orig, \%postdec);
{
no warnings 'uninitialized';
my ($x, $y);
eval {
$y ="$x\n";
++$x;
};
cmp_ok($x, '==', 1, "preincrement of previously uninitialized variable");
is($@, '', "no error condition");
my ($p, $q);
eval {
$q ="$p\n";
--$p;
};
cmp_ok($p, '==', -1, "predecrement of previously uninitialized variable");
is($@, '', "no error condition");
}
$a = 2147483648;
$c=--$a;
cmp_ok($a, '==', 2147483647, "predecrement properly downgrades from double");
$a = 2147483648;
$c=$a--;
cmp_ok($a, '==', 2147483647, "postdecrement properly downgrades from double");
{
use integer;
my $x = 0;
$x++;
cmp_ok($x, '==', 1, "(void) i_postinc");
$x--;
cmp_ok($x, '==', 0, "(void) i_postdec");
}
# I'm sure that there's an IBM format with a 48 bit mantissa
# IEEE doubles have a 53 bit mantissa
# 80 bit long doubles have a 64 bit mantissa
# sparcs have a 112 bit mantissa for their long doubles. Just to be awkward :-)
my $h_uv_max = 1 + (~0 >> 1);
my $found;
for my $n (47..113) {
my $power_of_2 = 2**$n;
my $plus_1 = $power_of_2 + 1;
next if $plus_1 != $power_of_2;
my ($start_p, $start_n);
if ($h_uv_max > $power_of_2 / 2) {
my $uv_max = 1 + 2 * (~0 >> 1);
# UV_MAX is 2**$something - 1, so subtract 1 to get the start value
$start_p = $uv_max - 1;
# whereas IV_MIN is -(2**$something), so subtract 2
$start_n = -$h_uv_max + 2;
print "# Mantissa overflows at 2**$n ($power_of_2)\n";
print "# But max UV ($uv_max) is greater so testing that\n";
} else {
print "# Testing 2**$n ($power_of_2) which overflows the mantissa\n";
$start_p = int($power_of_2 - 2);
$start_n = -$start_p;
my $check = $power_of_2 - 2;
die "Something wrong with our rounding assumptions: $check vs $start_p"
unless $start_p == $check;
}
foreach ([$start_p, '++$i', 'pre-inc', 'inc'],
[$start_p, '$i++', 'post-inc', 'inc'],
[$start_n, '--$i', 'pre-dec', 'dec'],
[$start_n, '$i--', 'post-dec', 'dec']) {
my ($start, $action, $description, $act) = @$_;
my $code = eval << "EOC" or die $@;
sub {
no warnings 'imprecision';
my \$i = \$start;
for(0 .. 3) {
my \$a = $action;
}
}
EOC
warning_is($code, undef, "$description under no warnings 'imprecision'");
$code = eval << "EOC" or die $@;
sub {
use warnings 'imprecision';
my \$i = \$start;
for(0 .. 3) {
my \$a = $action;
}
}
EOC
warnings_like($code, [(qr/Lost precision when ${act}rementing -?\d+/) x 2],
"$description under use warnings 'imprecision'");
}
$found = 1;
last;
}
die "Could not find a value which overflows the mantissa" unless $found;
# these will segfault if they fail
sub PVBM () { 'foo' }
{ my $dummy = index 'foo', PVBM }
isnt(scalar eval { my $pvbm = PVBM; $pvbm++ }, undef, "postincrement defined");
isnt(scalar eval { my $pvbm = PVBM; $pvbm-- }, undef, "postdecrement defined");
isnt(scalar eval { my $pvbm = PVBM; ++$pvbm }, undef, "preincrement defined");
isnt(scalar eval { my $pvbm = PVBM; --$pvbm }, undef, "predecrement defined");
# #9466
# don't use pad TARG when the thing you're copying is a ref, or the referent
# won't get freed.
{
package P9466;
my $x;
sub DESTROY { $x = 1 }
for (0..1) {
$x = 0;
my $a = bless {};
my $b = $_ ? $a++ : $a--;
undef $a; undef $b;
::is($x, 1, "9466 case $_");
}
}
$_ = ${qr //};
$_--;
is($_, -1, 'regexp--');
{
no warnings 'numeric';
$_ = ${qr //};
$_++;
is($_, 1, 'regexp++');
}
$_ = v97;
$_++;
isnt(ref\$_, 'VSTRING', '++ flattens vstrings');
done_testing();