| 1 |
package ExtUtils::Constant::Base; |
| 2 |
|
| 3 |
use strict; |
| 4 |
use vars qw($VERSION $is_perl56); |
| 5 |
use Carp; |
| 6 |
use Text::Wrap; |
| 7 |
use ExtUtils::Constant::Utils qw(C_stringify perl_stringify); |
| 8 |
|
| 9 |
$VERSION = '0.01'; |
| 10 |
|
| 11 |
$is_perl56 = ($] < 5.007 && $] > 5.005_50); |
| 12 |
|
| 13 |
|
| 14 |
=head1 NAME |
| 15 |
|
| 16 |
ExtUtils::Constant::Base - base class for ExtUtils::Constant objects |
| 17 |
|
| 18 |
=head1 SYNOPSIS |
| 19 |
|
| 20 |
require ExtUtils::Constant::Base; |
| 21 |
@ISA = 'ExtUtils::Constant::Base'; |
| 22 |
|
| 23 |
=head1 DESCRIPTION |
| 24 |
|
| 25 |
ExtUtils::Constant::Base provides a base implementation of methods to |
| 26 |
generate C code to give fast constant value lookup by named string. Currently |
| 27 |
it's mostly used ExtUtils::Constant::XS, which generates the lookup code |
| 28 |
for the constant() subroutine found in many XS modules. |
| 29 |
|
| 30 |
=head1 USAGE |
| 31 |
|
| 32 |
ExtUtils::Constant::Base exports no subroutines. The following methods are |
| 33 |
available |
| 34 |
|
| 35 |
=over 4 |
| 36 |
|
| 37 |
=cut |
| 38 |
|
| 39 |
sub valid_type { |
| 40 |
# Default to assuming that you don't need different types of return data. |
| 41 |
1; |
| 42 |
} |
| 43 |
sub default_type { |
| 44 |
''; |
| 45 |
} |
| 46 |
|
| 47 |
=item header |
| 48 |
|
| 49 |
A method returning a scalar containing definitions needed, typically for a |
| 50 |
C header file. |
| 51 |
|
| 52 |
=cut |
| 53 |
|
| 54 |
sub header { |
| 55 |
'' |
| 56 |
} |
| 57 |
|
| 58 |
# This might actually be a return statement. Note that you are responsible |
| 59 |
# for any space you might need before your value, as it lets to perform |
| 60 |
# "tricks" such as "return KEY_" and have strings appended. |
| 61 |
sub assignment_clause_for_type; |
| 62 |
# In which case this might be an empty string |
| 63 |
sub return_statement_for_type {undef}; |
| 64 |
sub return_statement_for_notdef; |
| 65 |
sub return_statement_for_notfound; |
| 66 |
|
| 67 |
# "#if 1" is true to a C pre-processor |
| 68 |
sub macro_from_name { |
| 69 |
1; |
| 70 |
} |
| 71 |
|
| 72 |
sub name_param { |
| 73 |
'name'; |
| 74 |
} |
| 75 |
|
| 76 |
# This is possibly buggy, in that it's not mandatory (below, in the main |
| 77 |
# C_constant parameters, but is expected to exist here, if it's needed) |
| 78 |
# Buggy because if you're definitely pure 8 bit only, and will never be |
| 79 |
# presented with your constants in utf8, the default form of C_constant can't |
| 80 |
# be told not to do the utf8 version. |
| 81 |
|
| 82 |
sub is_utf8_param { |
| 83 |
'utf8'; |
| 84 |
} |
| 85 |
|
| 86 |
sub memEQ { |
| 87 |
"!memcmp"; |
| 88 |
} |
| 89 |
|
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=item memEQ_clause args_hashref |
| 91 |
|
| 92 |
A method to return a suitable C C<if> statement to check whether I<name> |
| 93 |
is equal to the C variable C<name>. If I<checked_at> is defined, then it |
| 94 |
is used to avoid C<memEQ> for short names, or to generate a comment to |
| 95 |
highlight the position of the character in the C<switch> statement. |
| 96 |
|
| 97 |
If i<checked_at> is a reference to a scalar, then instead it gives |
| 98 |
the characters pre-checked at the beginning, (and the number of chars by |
| 99 |
which the C variable name has been advanced. These need to be chopped from |
| 100 |
the front of I<name>). |
| 101 |
|
| 102 |
=cut |
| 103 |
|
| 104 |
sub memEQ_clause { |
| 105 |
# if (memEQ(name, "thingy", 6)) { |
| 106 |
# Which could actually be a character comparison or even "" |
| 107 |
my ($self, $args) = @_; |
| 108 |
my ($name, $checked_at, $indent) = @{$args}{qw(name checked_at indent)}; |
| 109 |
$indent = ' ' x ($indent || 4); |
| 110 |
my $front_chop; |
| 111 |
if (ref $checked_at) { |
| 112 |
# regexp won't work on 5.6.1 without use utf8; in turn that won't work |
| 113 |
# on 5.005_03. |
| 114 |
substr ($name, 0, length $$checked_at,) = ''; |
| 115 |
$front_chop = C_stringify ($$checked_at); |
| 116 |
undef $checked_at; |
| 117 |
} |
| 118 |
my $len = length $name; |
| 119 |
|
| 120 |
if ($len < 2) { |
| 121 |
return $indent . "{\n" |
| 122 |
if (defined $checked_at and $checked_at == 0) or $len == 0; |
| 123 |
# We didn't switch, drop through to the code for the 2 character string |
| 124 |
$checked_at = 1; |
| 125 |
} |
| 126 |
|
| 127 |
my $name_param = $self->name_param; |
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|
| 129 |
if ($len < 3 and defined $checked_at) { |
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my $check; |
| 131 |
if ($checked_at == 1) { |
| 132 |
$check = 0; |
| 133 |
} elsif ($checked_at == 0) { |
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$check = 1; |
| 135 |
} |
| 136 |
if (defined $check) { |
| 137 |
my $char = C_stringify (substr $name, $check, 1); |
| 138 |
# Placate 5.005 with a break in the string. I can't see a good way of |
| 139 |
# getting it to not take [ as introducing an array lookup, even with |
| 140 |
# ${name_param}[$check] |
| 141 |
return $indent . "if ($name_param" . "[$check] == '$char') {\n"; |
| 142 |
} |
| 143 |
} |
| 144 |
if (($len == 2 and !defined $checked_at) |
| 145 |
or ($len == 3 and defined ($checked_at) and $checked_at == 2)) { |
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my $char1 = C_stringify (substr $name, 0, 1); |
| 147 |
my $char2 = C_stringify (substr $name, 1, 1); |
| 148 |
return $indent . |
| 149 |
"if ($name_param" . "[0] == '$char1' && $name_param" . "[1] == '$char2') {\n"; |
| 150 |
} |
| 151 |
if (($len == 3 and defined ($checked_at) and $checked_at == 1)) { |
| 152 |
my $char1 = C_stringify (substr $name, 0, 1); |
| 153 |
my $char2 = C_stringify (substr $name, 2, 1); |
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return $indent . |
| 155 |
"if ($name_param" . "[0] == '$char1' && $name_param" . "[2] == '$char2') {\n"; |
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} |
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|
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my $pointer = '^'; |
| 159 |
my $have_checked_last = defined ($checked_at) && $len == $checked_at + 1; |
| 160 |
if ($have_checked_last) { |
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# Checked at the last character, so no need to memEQ it. |
| 162 |
$pointer = C_stringify (chop $name); |
| 163 |
$len--; |
| 164 |
} |
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|
| 166 |
$name = C_stringify ($name); |
| 167 |
my $memEQ = $self->memEQ(); |
| 168 |
my $body = $indent . "if ($memEQ($name_param, \"$name\", $len)) {\n"; |
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# Put a little ^ under the letter we checked at |
| 170 |
# Screws up for non printable and non-7 bit stuff, but that's too hard to |
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# get right. |
| 172 |
if (defined $checked_at) { |
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$body .= $indent . "/* " . (' ' x length $memEQ) |
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. (' ' x length $name_param) |
| 175 |
. (' ' x $checked_at) . $pointer |
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. (' ' x ($len - $checked_at + length $len)) . " */\n"; |
| 177 |
} elsif (defined $front_chop) { |
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$body .= $indent . "/* $front_chop" |
| 179 |
. (' ' x ($len + 1 + length $len)) . " */\n"; |
| 180 |
} |
| 181 |
return $body; |
| 182 |
} |
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|
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=item dump_names arg_hashref, ITEM... |
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|
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An internal function to generate the embedded perl code that will regenerate |
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the constant subroutines. I<default_type>, I<types> and I<ITEM>s are the |
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same as for C_constant. I<indent> is treated as number of spaces to indent |
| 189 |
by. If C<declare_types> is true a C<$types> is always declared in the perl |
| 190 |
code generated, if defined and false never declared, and if undefined C<$types> |
| 191 |
is only declared if the values in I<types> as passed in cannot be inferred from |
| 192 |
I<default_types> and the I<ITEM>s. |
| 193 |
|
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=cut |
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|
| 196 |
sub dump_names { |
| 197 |
my ($self, $args, @items) = @_; |
| 198 |
my ($default_type, $what, $indent, $declare_types) |
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= @{$args}{qw(default_type what indent declare_types)}; |
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$indent = ' ' x ($indent || 0); |
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|
| 202 |
my $result; |
| 203 |
my (@simple, @complex, %used_types); |
| 204 |
foreach (@items) { |
| 205 |
my $type; |
| 206 |
if (ref $_) { |
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$type = $_->{type} || $default_type; |
| 208 |
if ($_->{utf8}) { |
| 209 |
# For simplicity always skip the bytes case, and reconstitute this entry |
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# from its utf8 twin. |
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next if $_->{utf8} eq 'no'; |
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# Copy the hashref, as we don't want to mess with the caller's hashref. |
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$_ = {%$_}; |
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unless ($is_perl56) { |
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utf8::decode ($_->{name}); |
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} else { |
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$_->{name} = pack 'U*', unpack 'U0U*', $_->{name}; |
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} |
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delete $_->{utf8}; |
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} |
| 221 |
} else { |
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$_ = {name=>$_}; |
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$type = $default_type; |
| 224 |
} |
| 225 |
$used_types{$type}++; |
| 226 |
if ($type eq $default_type |
| 227 |
# grr 5.6.1 |
| 228 |
and length $_->{name} |
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and length $_->{name} == ($_->{name} =~ tr/A-Za-z0-9_//) |
| 230 |
and !defined ($_->{macro}) and !defined ($_->{value}) |
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and !defined ($_->{default}) and !defined ($_->{pre}) |
| 232 |
and !defined ($_->{post}) and !defined ($_->{def_pre}) |
| 233 |
and !defined ($_->{def_post}) and !defined ($_->{weight})) { |
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# It's the default type, and the name consists only of A-Za-z0-9_ |
| 235 |
push @simple, $_->{name}; |
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} else { |
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push @complex, $_; |
| 238 |
} |
| 239 |
} |
| 240 |
|
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if (!defined $declare_types) { |
| 242 |
# Do they pass in any types we weren't already using? |
| 243 |
foreach (keys %$what) { |
| 244 |
next if $used_types{$_}; |
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$declare_types++; # Found one in $what that wasn't used. |
| 246 |
last; # And one is enough to terminate this loop |
| 247 |
} |
| 248 |
} |
| 249 |
if ($declare_types) { |
| 250 |
$result = $indent . 'my $types = {map {($_, 1)} qw(' |
| 251 |
. join (" ", sort keys %$what) . ")};\n"; |
| 252 |
} |
| 253 |
local $Text::Wrap::huge = 'overflow'; |
| 254 |
local $Text::Wrap::columns = 80; |
| 255 |
$result .= wrap ($indent . "my \@names = (qw(", |
| 256 |
$indent . " ", join (" ", sort @simple) . ")"); |
| 257 |
if (@complex) { |
| 258 |
foreach my $item (sort {$a->{name} cmp $b->{name}} @complex) { |
| 259 |
my $name = perl_stringify $item->{name}; |
| 260 |
my $line = ",\n$indent {name=>\"$name\""; |
| 261 |
$line .= ", type=>\"$item->{type}\"" if defined $item->{type}; |
| 262 |
foreach my $thing (qw (macro value default pre post def_pre def_post)) { |
| 263 |
my $value = $item->{$thing}; |
| 264 |
if (defined $value) { |
| 265 |
if (ref $value) { |
| 266 |
$line .= ", $thing=>[\"" |
| 267 |
. join ('", "', map {perl_stringify $_} @$value) . '"]'; |
| 268 |
} else { |
| 269 |
$line .= ", $thing=>\"" . perl_stringify($value) . "\""; |
| 270 |
} |
| 271 |
} |
| 272 |
} |
| 273 |
$line .= "}"; |
| 274 |
# Ensure that the enclosing C comment doesn't end |
| 275 |
# by turning */ into *" . "/ |
| 276 |
$line =~ s!\*\/!\*" . "/!gs; |
| 277 |
# gcc -Wall doesn't like finding /* inside a comment |
| 278 |
$line =~ s!\/\*!/" . "\*!gs; |
| 279 |
$result .= $line; |
| 280 |
} |
| 281 |
} |
| 282 |
$result .= ");\n"; |
| 283 |
|
| 284 |
$result; |
| 285 |
} |
| 286 |
|
| 287 |
=item assign arg_hashref, VALUE... |
| 288 |
|
| 289 |
A method to return a suitable assignment clause. If I<type> is aggregate |
| 290 |
(eg I<PVN> expects both pointer and length) then there should be multiple |
| 291 |
I<VALUE>s for the components. I<pre> and I<post> if defined give snippets |
| 292 |
of C code to proceed and follow the assignment. I<pre> will be at the start |
| 293 |
of a block, so variables may be defined in it. |
| 294 |
|
| 295 |
=cut |
| 296 |
# Hmm. value undef to to NOTDEF? value () to do NOTFOUND? |
| 297 |
|
| 298 |
sub assign { |
| 299 |
my $self = shift; |
| 300 |
my $args = shift; |
| 301 |
my ($indent, $type, $pre, $post, $item) |
| 302 |
= @{$args}{qw(indent type pre post item)}; |
| 303 |
$post ||= ''; |
| 304 |
my $clause; |
| 305 |
my $close; |
| 306 |
if ($pre) { |
| 307 |
chomp $pre; |
| 308 |
$close = "$indent}\n"; |
| 309 |
$clause = $indent . "{\n"; |
| 310 |
$indent .= " "; |
| 311 |
$clause .= "$indent$pre"; |
| 312 |
$clause .= ";" unless $pre =~ /;$/; |
| 313 |
$clause .= "\n"; |
| 314 |
} |
| 315 |
confess "undef \$type" unless defined $type; |
| 316 |
confess "Can't generate code for type $type" |
| 317 |
unless $self->valid_type($type); |
| 318 |
|
| 319 |
$clause .= join '', map {"$indent$_\n"} |
| 320 |
$self->assignment_clause_for_type({type=>$type,item=>$item}, @_); |
| 321 |
chomp $post; |
| 322 |
if (length $post) { |
| 323 |
$clause .= "$post"; |
| 324 |
$clause .= ";" unless $post =~ /;$/; |
| 325 |
$clause .= "\n"; |
| 326 |
} |
| 327 |
my $return = $self->return_statement_for_type($type); |
| 328 |
$clause .= "$indent$return\n" if defined $return; |
| 329 |
$clause .= $close if $close; |
| 330 |
return $clause; |
| 331 |
} |
| 332 |
|
| 333 |
=item return_clause arg_hashref, ITEM |
| 334 |
|
| 335 |
A method to return a suitable C<#ifdef> clause. I<ITEM> is a hashref |
| 336 |
(as passed to C<C_constant> and C<match_clause>. I<indent> is the number |
| 337 |
of spaces to indent, defaulting to 6. |
| 338 |
|
| 339 |
=cut |
| 340 |
|
| 341 |
sub return_clause { |
| 342 |
|
| 343 |
##ifdef thingy |
| 344 |
# *iv_return = thingy; |
| 345 |
# return PERL_constant_ISIV; |
| 346 |
##else |
| 347 |
# return PERL_constant_NOTDEF; |
| 348 |
##endif |
| 349 |
my ($self, $args, $item) = @_; |
| 350 |
my $indent = $args->{indent}; |
| 351 |
|
| 352 |
my ($name, $value, $macro, $default, $pre, $post, $def_pre, $def_post, $type) |
| 353 |
= @$item{qw (name value macro default pre post def_pre def_post type)}; |
| 354 |
$value = $name unless defined $value; |
| 355 |
$macro = $self->macro_from_name($item) unless defined $macro; |
| 356 |
# "#if 1" is true to a C pre-processor |
| 357 |
$macro = 1 if !defined $macro or $macro eq ''; |
| 358 |
$indent = ' ' x ($indent || 6); |
| 359 |
unless (defined $type) { |
| 360 |
# use Data::Dumper; print STDERR Dumper ($item); |
| 361 |
confess "undef \$type"; |
| 362 |
} |
| 363 |
|
| 364 |
my $clause; |
| 365 |
|
| 366 |
##ifdef thingy |
| 367 |
if (ref $macro) { |
| 368 |
$clause = $macro->[0]; |
| 369 |
} elsif ($macro ne "1") { |
| 370 |
$clause = "#ifdef $macro\n"; |
| 371 |
} |
| 372 |
|
| 373 |
# *iv_return = thingy; |
| 374 |
# return PERL_constant_ISIV; |
| 375 |
$clause |
| 376 |
.= $self->assign ({indent=>$indent, type=>$type, pre=>$pre, post=>$post, |
| 377 |
item=>$item}, ref $value ? @$value : $value); |
| 378 |
|
| 379 |
if (ref $macro or $macro ne "1") { |
| 380 |
##else |
| 381 |
$clause .= "#else\n"; |
| 382 |
|
| 383 |
# return PERL_constant_NOTDEF; |
| 384 |
if (!defined $default) { |
| 385 |
my $notdef = $self->return_statement_for_notdef(); |
| 386 |
$clause .= "$indent$notdef\n" if defined $notdef; |
| 387 |
} else { |
| 388 |
my @default = ref $default ? @$default : $default; |
| 389 |
$type = shift @default; |
| 390 |
$clause .= $self->assign ({indent=>$indent, type=>$type, pre=>$pre, |
| 391 |
post=>$post, item=>$item}, @default); |
| 392 |
} |
| 393 |
|
| 394 |
##endif |
| 395 |
if (ref $macro) { |
| 396 |
$clause .= $macro->[1]; |
| 397 |
} else { |
| 398 |
$clause .= "#endif\n"; |
| 399 |
} |
| 400 |
} |
| 401 |
return $clause; |
| 402 |
} |
| 403 |
|
| 404 |
sub match_clause { |
| 405 |
# $offset defined if we have checked an offset. |
| 406 |
my ($self, $args, $item) = @_; |
| 407 |
my ($offset, $indent) = @{$args}{qw(checked_at indent)}; |
| 408 |
$indent = ' ' x ($indent || 4); |
| 409 |
my $body = ''; |
| 410 |
my ($no, $yes, $either, $name, $inner_indent); |
| 411 |
if (ref $item eq 'ARRAY') { |
| 412 |
($yes, $no) = @$item; |
| 413 |
$either = $yes || $no; |
| 414 |
confess "$item is $either expecting hashref in [0] || [1]" |
| 415 |
unless ref $either eq 'HASH'; |
| 416 |
$name = $either->{name}; |
| 417 |
} else { |
| 418 |
confess "$item->{name} has utf8 flag '$item->{utf8}', should be false" |
| 419 |
if $item->{utf8}; |
| 420 |
$name = $item->{name}; |
| 421 |
$inner_indent = $indent; |
| 422 |
} |
| 423 |
|
| 424 |
$body .= $self->memEQ_clause ({name => $name, checked_at => $offset, |
| 425 |
indent => length $indent}); |
| 426 |
# If we've been presented with an arrayref for $item, then the user string |
| 427 |
# contains in the range 128-255, and we need to check whether it was utf8 |
| 428 |
# (or not). |
| 429 |
# In the worst case we have two named constants, where one's name happens |
| 430 |
# encoded in UTF8 happens to be the same byte sequence as the second's |
| 431 |
# encoded in (say) ISO-8859-1. |
| 432 |
# In this case, $yes and $no both have item hashrefs. |
| 433 |
if ($yes) { |
| 434 |
$body .= $indent . " if (" . $self->is_utf8_param . ") {\n"; |
| 435 |
} elsif ($no) { |
| 436 |
$body .= $indent . " if (!" . $self->is_utf8_param . ") {\n"; |
| 437 |
} |
| 438 |
if ($either) { |
| 439 |
$body .= $self->return_clause ({indent=>4 + length $indent}, $either); |
| 440 |
if ($yes and $no) { |
| 441 |
$body .= $indent . " } else {\n"; |
| 442 |
$body .= $self->return_clause ({indent=>4 + length $indent}, $no); |
| 443 |
} |
| 444 |
$body .= $indent . " }\n"; |
| 445 |
} else { |
| 446 |
$body .= $self->return_clause ({indent=>2 + length $indent}, $item); |
| 447 |
} |
| 448 |
$body .= $indent . "}\n"; |
| 449 |
} |
| 450 |
|
| 451 |
|
| 452 |
=item switch_clause arg_hashref, NAMELEN, ITEMHASH, ITEM... |
| 453 |
|
| 454 |
An internal method to generate a suitable C<switch> clause, called by |
| 455 |
C<C_constant> I<ITEM>s are in the hash ref format as given in the description |
| 456 |
of C<C_constant>, and must all have the names of the same length, given by |
| 457 |
I<NAMELEN>. I<ITEMHASH> is a reference to a hash, keyed by name, values being |
| 458 |
the hashrefs in the I<ITEM> list. (No parameters are modified, and there can |
| 459 |
be keys in the I<ITEMHASH> that are not in the list of I<ITEM>s without |
| 460 |
causing problems - the hash is passed in to save generating it afresh for |
| 461 |
each call). |
| 462 |
|
| 463 |
=cut |
| 464 |
|
| 465 |
sub switch_clause { |
| 466 |
my ($self, $args, $namelen, $items, @items) = @_; |
| 467 |
my ($indent, $comment) = @{$args}{qw(indent comment)}; |
| 468 |
$indent = ' ' x ($indent || 2); |
| 469 |
|
| 470 |
local $Text::Wrap::huge = 'overflow'; |
| 471 |
local $Text::Wrap::columns = 80; |
| 472 |
|
| 473 |
my @names = sort map {$_->{name}} @items; |
| 474 |
my $leader = $indent . '/* '; |
| 475 |
my $follower = ' ' x length $leader; |
| 476 |
my $body = $indent . "/* Names all of length $namelen. */\n"; |
| 477 |
if (defined $comment) { |
| 478 |
$body = wrap ($leader, $follower, $comment) . "\n"; |
| 479 |
$leader = $follower; |
| 480 |
} |
| 481 |
my @safe_names = @names; |
| 482 |
foreach (@safe_names) { |
| 483 |
confess sprintf "Name '$_' is length %d, not $namelen", length |
| 484 |
unless length == $namelen; |
| 485 |
# Argh. 5.6.1 |
| 486 |
# next unless tr/A-Za-z0-9_//c; |
| 487 |
next if tr/A-Za-z0-9_// == length; |
| 488 |
$_ = '"' . perl_stringify ($_) . '"'; |
| 489 |
# Ensure that the enclosing C comment doesn't end |
| 490 |
# by turning */ into *" . "/ |
| 491 |
s!\*\/!\*"."/!gs; |
| 492 |
# gcc -Wall doesn't like finding /* inside a comment |
| 493 |
s!\/\*!/"."\*!gs; |
| 494 |
} |
| 495 |
$body .= wrap ($leader, $follower, join (" ", @safe_names) . " */") . "\n"; |
| 496 |
# Figure out what to switch on. |
| 497 |
# (RMS, Spread of jump table, Position, Hashref) |
| 498 |
my @best = (1e38, ~0); |
| 499 |
# Prefer the last character over the others. (As it lets us shorten the |
| 500 |
# memEQ clause at no cost). |
| 501 |
foreach my $i ($namelen - 1, 0 .. ($namelen - 2)) { |
| 502 |
my ($min, $max) = (~0, 0); |
| 503 |
my %spread; |
| 504 |
if ($is_perl56) { |
| 505 |
# Need proper Unicode preserving hash keys for bytes in range 128-255 |
| 506 |
# here too, for some reason. grr 5.6.1 yet again. |
| 507 |
tie %spread, 'ExtUtils::Constant::Aaargh56Hash'; |
| 508 |
} |
| 509 |
foreach (@names) { |
| 510 |
my $char = substr $_, $i, 1; |
| 511 |
my $ord = ord $char; |
| 512 |
confess "char $ord is out of range" if $ord > 255; |
| 513 |
$max = $ord if $ord > $max; |
| 514 |
$min = $ord if $ord < $min; |
| 515 |
push @{$spread{$char}}, $_; |
| 516 |
# warn "$_ $char"; |
| 517 |
} |
| 518 |
# I'm going to pick the character to split on that minimises the root |
| 519 |
# mean square of the number of names in each case. Normally this should |
| 520 |
# be the one with the most keys, but it may pick a 7 where the 8 has |
| 521 |
# one long linear search. I'm not sure if RMS or just sum of squares is |
| 522 |
# actually better. |
| 523 |
# $max and $min are for the tie-breaker if the root mean squares match. |
| 524 |
# Assuming that the compiler may be building a jump table for the |
| 525 |
# switch() then try to minimise the size of that jump table. |
| 526 |
# Finally use < not <= so that if it still ties the earliest part of |
| 527 |
# the string wins. Because if that passes but the memEQ fails, it may |
| 528 |
# only need the start of the string to bin the choice. |
| 529 |
# I think. But I'm micro-optimising. :-) |
| 530 |
# OK. Trump that. Now favour the last character of the string, before the |
| 531 |
# rest. |
| 532 |
my $ss; |
| 533 |
$ss += @$_ * @$_ foreach values %spread; |
| 534 |
my $rms = sqrt ($ss / keys %spread); |
| 535 |
if ($rms < $best[0] || ($rms == $best[0] && ($max - $min) < $best[1])) { |
| 536 |
@best = ($rms, $max - $min, $i, \%spread); |
| 537 |
} |
| 538 |
} |
| 539 |
confess "Internal error. Failed to pick a switch point for @names" |
| 540 |
unless defined $best[2]; |
| 541 |
# use Data::Dumper; print Dumper (@best); |
| 542 |
my ($offset, $best) = @best[2,3]; |
| 543 |
$body .= $indent . "/* Offset $offset gives the best switch position. */\n"; |
| 544 |
|
| 545 |
my $do_front_chop = $offset == 0 && $namelen > 2; |
| 546 |
if ($do_front_chop) { |
| 547 |
$body .= $indent . "switch (*" . $self->name_param() . "++) {\n"; |
| 548 |
} else { |
| 549 |
$body .= $indent . "switch (" . $self->name_param() . "[$offset]) {\n"; |
| 550 |
} |
| 551 |
foreach my $char (sort keys %$best) { |
| 552 |
confess sprintf "'$char' is %d bytes long, not 1", length $char |
| 553 |
if length ($char) != 1; |
| 554 |
confess sprintf "char %#X is out of range", ord $char if ord ($char) > 255; |
| 555 |
$body .= $indent . "case '" . C_stringify ($char) . "':\n"; |
| 556 |
foreach my $thisone (sort { |
| 557 |
# Deal with the case of an item actually being an array ref to 1 or 2 |
| 558 |
# hashrefs. Don't assign to $a or $b, as they're aliases to the orignal |
| 559 |
my $l = ref $a eq 'ARRAY' ? ($a->[0] || $->[1]) : $a; |
| 560 |
my $r = ref $b eq 'ARRAY' ? ($b->[0] || $->[1]) : $b; |
| 561 |
# Sort by weight first |
| 562 |
($r->{weight} || 0) <=> ($l->{weight} || 0) |
| 563 |
# Sort equal weights by name |
| 564 |
or $l->{name} cmp $r->{name}} |
| 565 |
# If this looks evil, maybe it is. $items is a |
| 566 |
# hashref, and we're doing a hash slice on it |
| 567 |
@{$items}{@{$best->{$char}}}) { |
| 568 |
# warn "You are here"; |
| 569 |
if ($do_front_chop) { |
| 570 |
$body .= $self->match_clause ({indent => 2 + length $indent, |
| 571 |
checked_at => \$char}, $thisone); |
| 572 |
} else { |
| 573 |
$body .= $self->match_clause ({indent => 2 + length $indent, |
| 574 |
checked_at => $offset}, $thisone); |
| 575 |
} |
| 576 |
} |
| 577 |
$body .= $indent . " break;\n"; |
| 578 |
} |
| 579 |
$body .= $indent . "}\n"; |
| 580 |
return $body; |
| 581 |
} |
| 582 |
|
| 583 |
sub C_constant_return_type { |
| 584 |
"static int"; |
| 585 |
} |
| 586 |
|
| 587 |
sub C_constant_prefix_param { |
| 588 |
''; |
| 589 |
} |
| 590 |
|
| 591 |
sub C_constant_prefix_param_defintion { |
| 592 |
''; |
| 593 |
} |
| 594 |
|
| 595 |
sub name_param_definition { |
| 596 |
"const char *" . $_[0]->name_param; |
| 597 |
} |
| 598 |
|
| 599 |
sub namelen_param { |
| 600 |
'len'; |
| 601 |
} |
| 602 |
|
| 603 |
sub namelen_param_definition { |
| 604 |
'size_t ' . $_[0]->namelen_param; |
| 605 |
} |
| 606 |
|
| 607 |
sub C_constant_other_params { |
| 608 |
''; |
| 609 |
} |
| 610 |
|
| 611 |
sub C_constant_other_params_defintion { |
| 612 |
''; |
| 613 |
} |
| 614 |
|
| 615 |
=item params WHAT |
| 616 |
|
| 617 |
An "internal" method, subject to change, currently called to allow an |
| 618 |
overriding class to cache information that will then be passed into all |
| 619 |
the C<*param*> calls. (Yes, having to read the source to make sense of this is |
| 620 |
considered a known bug). I<WHAT> is be a hashref of types the constant |
| 621 |
function will return. In ExtUtils::Constant::XS this method is used to |
| 622 |
returns a hashref keyed IV NV PV SV to show which combination of pointers will |
| 623 |
be needed in the C argument list generated by |
| 624 |
C_constant_other_params_definition and C_constant_other_params |
| 625 |
|
| 626 |
=cut |
| 627 |
|
| 628 |
sub params { |
| 629 |
''; |
| 630 |
} |
| 631 |
|
| 632 |
|
| 633 |
=item dogfood arg_hashref, ITEM... |
| 634 |
|
| 635 |
An internal function to generate the embedded perl code that will regenerate |
| 636 |
the constant subroutines. Parameters are the same as for C_constant. |
| 637 |
|
| 638 |
Currently the base class does nothing and returns an empty string. |
| 639 |
|
| 640 |
=cut |
| 641 |
|
| 642 |
sub dogfood { |
| 643 |
'' |
| 644 |
} |
| 645 |
|
| 646 |
=item C_constant arg_hashref, ITEM... |
| 647 |
|
| 648 |
A function that returns a B<list> of C subroutine definitions that return |
| 649 |
the value and type of constants when passed the name by the XS wrapper. |
| 650 |
I<ITEM...> gives a list of constant names. Each can either be a string, |
| 651 |
which is taken as a C macro name, or a reference to a hash with the following |
| 652 |
keys |
| 653 |
|
| 654 |
=over 8 |
| 655 |
|
| 656 |
=item name |
| 657 |
|
| 658 |
The name of the constant, as seen by the perl code. |
| 659 |
|
| 660 |
=item type |
| 661 |
|
| 662 |
The type of the constant (I<IV>, I<NV> etc) |
| 663 |
|
| 664 |
=item value |
| 665 |
|
| 666 |
A C expression for the value of the constant, or a list of C expressions if |
| 667 |
the type is aggregate. This defaults to the I<name> if not given. |
| 668 |
|
| 669 |
=item macro |
| 670 |
|
| 671 |
The C pre-processor macro to use in the C<#ifdef>. This defaults to the |
| 672 |
I<name>, and is mainly used if I<value> is an C<enum>. If a reference an |
| 673 |
array is passed then the first element is used in place of the C<#ifdef> |
| 674 |
line, and the second element in place of the C<#endif>. This allows |
| 675 |
pre-processor constructions such as |
| 676 |
|
| 677 |
#if defined (foo) |
| 678 |
#if !defined (bar) |
| 679 |
... |
| 680 |
#endif |
| 681 |
#endif |
| 682 |
|
| 683 |
to be used to determine if a constant is to be defined. |
| 684 |
|
| 685 |
A "macro" 1 signals that the constant is always defined, so the C<#if>/C<#endif> |
| 686 |
test is omitted. |
| 687 |
|
| 688 |
=item default |
| 689 |
|
| 690 |
Default value to use (instead of C<croak>ing with "your vendor has not |
| 691 |
defined...") to return if the macro isn't defined. Specify a reference to |
| 692 |
an array with type followed by value(s). |
| 693 |
|
| 694 |
=item pre |
| 695 |
|
| 696 |
C code to use before the assignment of the value of the constant. This allows |
| 697 |
you to use temporary variables to extract a value from part of a C<struct> |
| 698 |
and return this as I<value>. This C code is places at the start of a block, |
| 699 |
so you can declare variables in it. |
| 700 |
|
| 701 |
=item post |
| 702 |
|
| 703 |
C code to place between the assignment of value (to a temporary) and the |
| 704 |
return from the function. This allows you to clear up anything in I<pre>. |
| 705 |
Rarely needed. |
| 706 |
|
| 707 |
=item def_pre |
| 708 |
|
| 709 |
=item def_post |
| 710 |
|
| 711 |
Equivalents of I<pre> and I<post> for the default value. |
| 712 |
|
| 713 |
=item utf8 |
| 714 |
|
| 715 |
Generated internally. Is zero or undefined if name is 7 bit ASCII, |
| 716 |
"no" if the name is 8 bit (and so should only match if SvUTF8() is false), |
| 717 |
"yes" if the name is utf8 encoded. |
| 718 |
|
| 719 |
The internals automatically clone any name with characters 128-255 but none |
| 720 |
256+ (ie one that could be either in bytes or utf8) into a second entry |
| 721 |
which is utf8 encoded. |
| 722 |
|
| 723 |
=item weight |
| 724 |
|
| 725 |
Optional sorting weight for names, to determine the order of |
| 726 |
linear testing when multiple names fall in the same case of a switch clause. |
| 727 |
Higher comes earlier, undefined defaults to zero. |
| 728 |
|
| 729 |
=back |
| 730 |
|
| 731 |
In the argument hashref, I<package> is the name of the package, and is only |
| 732 |
used in comments inside the generated C code. I<subname> defaults to |
| 733 |
C<constant> if undefined. |
| 734 |
|
| 735 |
I<default_type> is the type returned by C<ITEM>s that don't specify their |
| 736 |
type. It defaults to the value of C<default_type()>. I<types> should be given |
| 737 |
either as a comma separated list of types that the C subroutine I<subname> |
| 738 |
will generate or as a reference to a hash. I<default_type> will be added to |
| 739 |
the list if not present, as will any types given in the list of I<ITEM>s. The |
| 740 |
resultant list should be the same list of types that C<XS_constant> is |
| 741 |
given. [Otherwise C<XS_constant> and C<C_constant> may differ in the number of |
| 742 |
parameters to the constant function. I<indent> is currently unused and |
| 743 |
ignored. In future it may be used to pass in information used to change the C |
| 744 |
indentation style used.] The best way to maintain consistency is to pass in a |
| 745 |
hash reference and let this function update it. |
| 746 |
|
| 747 |
I<breakout> governs when child functions of I<subname> are generated. If there |
| 748 |
are I<breakout> or more I<ITEM>s with the same length of name, then the code |
| 749 |
to switch between them is placed into a function named I<subname>_I<len>, for |
| 750 |
example C<constant_5> for names 5 characters long. The default I<breakout> is |
| 751 |
3. A single C<ITEM> is always inlined. |
| 752 |
|
| 753 |
=cut |
| 754 |
|
| 755 |
# The parameter now BREAKOUT was previously documented as: |
| 756 |
# |
| 757 |
# I<NAMELEN> if defined signals that all the I<name>s of the I<ITEM>s are of |
| 758 |
# this length, and that the constant name passed in by perl is checked and |
| 759 |
# also of this length. It is used during recursion, and should be C<undef> |
| 760 |
# unless the caller has checked all the lengths during code generation, and |
| 761 |
# the generated subroutine is only to be called with a name of this length. |
| 762 |
# |
| 763 |
# As you can see it now performs this function during recursion by being a |
| 764 |
# scalar reference. |
| 765 |
|
| 766 |
sub C_constant { |
| 767 |
my ($self, $args, @items) = @_; |
| 768 |
my ($package, $subname, $default_type, $what, $indent, $breakout) = |
| 769 |
@{$args}{qw(package subname default_type types indent breakout)}; |
| 770 |
$package ||= 'Foo'; |
| 771 |
$subname ||= 'constant'; |
| 772 |
# I'm not using this. But a hashref could be used for full formatting without |
| 773 |
# breaking this API |
| 774 |
# $indent ||= 0; |
| 775 |
|
| 776 |
my ($namelen, $items); |
| 777 |
if (ref $breakout) { |
| 778 |
# We are called recursively. We trust @items to be normalised, $what to |
| 779 |
# be a hashref, and pinch %$items from our parent to save recalculation. |
| 780 |
($namelen, $items) = @$breakout; |
| 781 |
} else { |
| 782 |
if ($is_perl56) { |
| 783 |
# Need proper Unicode preserving hash keys. |
| 784 |
require ExtUtils::Constant::Aaargh56Hash; |
| 785 |
$items = {}; |
| 786 |
tie %$items, 'ExtUtils::Constant::Aaargh56Hash'; |
| 787 |
} |
| 788 |
$breakout ||= 3; |
| 789 |
$default_type ||= $self->default_type(); |
| 790 |
if (!ref $what) { |
| 791 |
# Convert line of the form IV,UV,NV to hash |
| 792 |
$what = {map {$_ => 1} split /,\s*/, ($what || '')}; |
| 793 |
# Figure out what types we're dealing with, and assign all unknowns to the |
| 794 |
# default type |
| 795 |
} |
| 796 |
my @new_items; |
| 797 |
foreach my $orig (@items) { |
| 798 |
my ($name, $item); |
| 799 |
if (ref $orig) { |
| 800 |
# Make a copy which is a normalised version of the ref passed in. |
| 801 |
$name = $orig->{name}; |
| 802 |
my ($type, $macro, $value) = @$orig{qw (type macro value)}; |
| 803 |
$type ||= $default_type; |
| 804 |
$what->{$type} = 1; |
| 805 |
$item = {name=>$name, type=>$type}; |
| 806 |
|
| 807 |
undef $macro if defined $macro and $macro eq $name; |
| 808 |
$item->{macro} = $macro if defined $macro; |
| 809 |
undef $value if defined $value and $value eq $name; |
| 810 |
$item->{value} = $value if defined $value; |
| 811 |
foreach my $key (qw(default pre post def_pre def_post weight)) { |
| 812 |
my $value = $orig->{$key}; |
| 813 |
$item->{$key} = $value if defined $value; |
| 814 |
# warn "$key $value"; |
| 815 |
} |
| 816 |
} else { |
| 817 |
$name = $orig; |
| 818 |
$item = {name=>$name, type=>$default_type}; |
| 819 |
$what->{$default_type} = 1; |
| 820 |
} |
| 821 |
warn +(ref ($self) || $self) |
| 822 |
. "doesn't know how to handle values of type $_ used in macro $name" |
| 823 |
unless $self->valid_type ($item->{type}); |
| 824 |
# tr///c is broken on 5.6.1 for utf8, so my original tr/\0-\177//c |
| 825 |
# doesn't work. Upgrade to 5.8 |
| 826 |
# if ($name !~ tr/\0-\177//c || $] < 5.005_50) { |
| 827 |
if ($name =~ tr/\0-\177// == length $name || $] < 5.005_50) { |
| 828 |
# No characters outside 7 bit ASCII. |
| 829 |
if (exists $items->{$name}) { |
| 830 |
die "Multiple definitions for macro $name"; |
| 831 |
} |
| 832 |
$items->{$name} = $item; |
| 833 |
} else { |
| 834 |
# No characters outside 8 bit. This is hardest. |
| 835 |
if (exists $items->{$name} and ref $items->{$name} ne 'ARRAY') { |
| 836 |
confess "Unexpected ASCII definition for macro $name"; |
| 837 |
} |
| 838 |
# Again, 5.6.1 tr broken, so s/5\.6.*/5\.8\.0/; |
| 839 |
# if ($name !~ tr/\0-\377//c) { |
| 840 |
if ($name =~ tr/\0-\377// == length $name) { |
| 841 |
# if ($] < 5.007) { |
| 842 |
# $name = pack "C*", unpack "U*", $name; |
| 843 |
# } |
| 844 |
$item->{utf8} = 'no'; |
| 845 |
$items->{$name}[1] = $item; |
| 846 |
push @new_items, $item; |
| 847 |
# Copy item, to create the utf8 variant. |
| 848 |
$item = {%$item}; |
| 849 |
} |
| 850 |
# Encode the name as utf8 bytes. |
| 851 |
unless ($is_perl56) { |
| 852 |
utf8::encode($name); |
| 853 |
} else { |
| 854 |
# warn "Was >$name< " . length ${name}; |
| 855 |
$name = pack 'C*', unpack 'C*', $name . pack 'U*'; |
| 856 |
# warn "Now '${name}' " . length ${name}; |
| 857 |
} |
| 858 |
if ($items->{$name}[0]) { |
| 859 |
die "Multiple definitions for macro $name"; |
| 860 |
} |
| 861 |
$item->{utf8} = 'yes'; |
| 862 |
$item->{name} = $name; |
| 863 |
$items->{$name}[0] = $item; |
| 864 |
# We have need for the utf8 flag. |
| 865 |
$what->{''} = 1; |
| 866 |
} |
| 867 |
push @new_items, $item; |
| 868 |
} |
| 869 |
@items = @new_items; |
| 870 |
# use Data::Dumper; print Dumper @items; |
| 871 |
} |
| 872 |
my $params = $self->params ($what); |
| 873 |
|
| 874 |
# Probably "static int" |
| 875 |
my ($body, @subs); |
| 876 |
$body = $self->C_constant_return_type($params) . "\n$subname (" |
| 877 |
# Eg "pTHX_ " |
| 878 |
. $self->C_constant_prefix_param_defintion($params) |
| 879 |
# Probably "const char *name" |
| 880 |
. $self->name_param_definition($params); |
| 881 |
# Something like ", STRLEN len" |
| 882 |
$body .= ", " . $self->namelen_param_definition($params) |
| 883 |
unless defined $namelen; |
| 884 |
$body .= $self->C_constant_other_params_defintion($params); |
| 885 |
$body .= ") {\n"; |
| 886 |
|
| 887 |
if (defined $namelen) { |
| 888 |
# We are a child subroutine. Print the simple description |
| 889 |
my $comment = 'When generated this function returned values for the list' |
| 890 |
. ' of names given here. However, subsequent manual editing may have' |
| 891 |
. ' added or removed some.'; |
| 892 |
$body .= $self->switch_clause ({indent=>2, comment=>$comment}, |
| 893 |
$namelen, $items, @items); |
| 894 |
} else { |
| 895 |
# We are the top level. |
| 896 |
$body .= " /* Initially switch on the length of the name. */\n"; |
| 897 |
$body .= $self->dogfood ({package => $package, subname => $subname, |
| 898 |
default_type => $default_type, what => $what, |
| 899 |
indent => $indent, breakout => $breakout}, |
| 900 |
@items); |
| 901 |
$body .= ' switch ('.$self->namelen_param().") {\n"; |
| 902 |
# Need to group names of the same length |
| 903 |
my @by_length; |
| 904 |
foreach (@items) { |
| 905 |
push @{$by_length[length $_->{name}]}, $_; |
| 906 |
} |
| 907 |
foreach my $i (0 .. $#by_length) { |
| 908 |
next unless $by_length[$i]; # None of this length |
| 909 |
$body .= " case $i:\n"; |
| 910 |
if (@{$by_length[$i]} == 1) { |
| 911 |
my $only_thing = $by_length[$i]->[0]; |
| 912 |
if ($only_thing->{utf8}) { |
| 913 |
if ($only_thing->{utf8} eq 'yes') { |
| 914 |
# With utf8 on flag item is passed in element 0 |
| 915 |
$body .= $self->match_clause (undef, [$only_thing]); |
| 916 |
} else { |
| 917 |
# With utf8 off flag item is passed in element 1 |
| 918 |
$body .= $self->match_clause (undef, [undef, $only_thing]); |
| 919 |
} |
| 920 |
} else { |
| 921 |
$body .= $self->match_clause (undef, $only_thing); |
| 922 |
} |
| 923 |
} elsif (@{$by_length[$i]} < $breakout) { |
| 924 |
$body .= $self->switch_clause ({indent=>4}, |
| 925 |
$i, $items, @{$by_length[$i]}); |
| 926 |
} else { |
| 927 |
# Only use the minimal set of parameters actually needed by the types |
| 928 |
# of the names of this length. |
| 929 |
my $what = {}; |
| 930 |
foreach (@{$by_length[$i]}) { |
| 931 |
$what->{$_->{type}} = 1; |
| 932 |
$what->{''} = 1 if $_->{utf8}; |
| 933 |
} |
| 934 |
$params = $self->params ($what); |
| 935 |
push @subs, $self->C_constant ({package=>$package, |
| 936 |
subname=>"${subname}_$i", |
| 937 |
default_type => $default_type, |
| 938 |
types => $what, indent => $indent, |
| 939 |
breakout => [$i, $items]}, |
| 940 |
@{$by_length[$i]}); |
| 941 |
$body .= " return ${subname}_$i (" |
| 942 |
# Eg "aTHX_ " |
| 943 |
. $self->C_constant_prefix_param($params) |
| 944 |
# Probably "name" |
| 945 |
. $self->name_param($params); |
| 946 |
$body .= $self->C_constant_other_params($params); |
| 947 |
$body .= ");\n"; |
| 948 |
} |
| 949 |
$body .= " break;\n"; |
| 950 |
} |
| 951 |
$body .= " }\n"; |
| 952 |
} |
| 953 |
my $notfound = $self->return_statement_for_notfound(); |
| 954 |
$body .= " $notfound\n" if $notfound; |
| 955 |
$body .= "}\n"; |
| 956 |
return (@subs, $body); |
| 957 |
} |
| 958 |
|
| 959 |
1; |
| 960 |
__END__ |
| 961 |
|
| 962 |
=back |
| 963 |
|
| 964 |
=head1 BUGS |
| 965 |
|
| 966 |
Not everything is documented yet. |
| 967 |
|
| 968 |
Probably others. |
| 969 |
|
| 970 |
=head1 AUTHOR |
| 971 |
|
| 972 |
Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and |
| 973 |
others |
