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1 | package ExtUtils::Constant; |
8ac27563 |
2 | use vars qw (@ISA $VERSION %XS_Constant %XS_TypeSet @EXPORT_OK %EXPORT_TAGS); |
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3 | $VERSION = '0.06'; |
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4 | |
5 | =head1 NAME |
6 | |
7 | ExtUtils::Constant - generate XS code to import C header constants |
8 | |
9 | =head1 SYNOPSIS |
10 | |
11 | use ExtUtils::Constant qw (constant_types C_constant XS_constant); |
12 | print constant_types(); # macro defs |
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13 | foreach (C_constant ("Foo", undef, "IV", undef, undef, undef, |
14 | @names) ) { |
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15 | print $_, "\n"; # C constant subs |
16 | } |
17 | print "MODULE = Foo PACKAGE = Foo\n"; |
18 | print XS_constant ("Foo", {NV => 1, IV => 1}); # XS for Foo::constant |
19 | |
20 | =head1 DESCRIPTION |
21 | |
22 | ExtUtils::Constant facilitates generating C and XS wrapper code to allow |
23 | perl modules to AUTOLOAD constants defined in C library header files. |
24 | It is principally used by the C<h2xs> utility, on which this code is based. |
25 | It doesn't contain the routines to scan header files to extract these |
26 | constants. |
27 | |
28 | =head1 USAGE |
29 | |
30 | Generally one only needs to call the 3 functions shown in the synopsis, |
31 | C<constant_types()>, C<C_constant> and C<XS_constant>. |
32 | |
33 | Currently this module understands the following types. h2xs may only know |
34 | a subset. The sizes of the numeric types are chosen by the C<Configure> |
35 | script at compile time. |
36 | |
37 | =over 4 |
38 | |
39 | =item IV |
40 | |
41 | signed integer, at least 32 bits. |
42 | |
43 | =item UV |
44 | |
45 | unsigned integer, the same size as I<IV> |
46 | |
47 | =item NV |
48 | |
49 | floating point type, probably C<double>, possibly C<long double> |
50 | |
51 | =item PV |
52 | |
53 | NUL terminated string, length will be determined with C<strlen> |
54 | |
55 | =item PVN |
56 | |
57 | A fixed length thing, given as a [pointer, length] pair. If you know the |
58 | length of a string at compile time you may use this instead of I<PV> |
59 | |
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60 | =item PVN |
61 | |
62 | A B<mortal> SV. |
63 | |
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64 | =item YES |
65 | |
66 | Truth. (C<PL_sv_yes>) The value is not needed (and ignored). |
67 | |
68 | =item NO |
69 | |
70 | Defined Falsehood. (C<PL_sv_no>) The value is not needed (and ignored). |
71 | |
72 | =item UNDEF |
73 | |
74 | C<undef>. The value of the macro is not needed. |
75 | |
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76 | =back |
77 | |
78 | =head1 FUNCTIONS |
79 | |
80 | =over 4 |
81 | |
82 | =cut |
83 | |
84 | require 5.006; # I think, for [:cntrl:] in REGEXP |
85 | use warnings; |
86 | use strict; |
87 | use Carp; |
88 | |
89 | use Exporter; |
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90 | use Text::Wrap; |
91 | $Text::Wrap::huge = 'overflow'; |
92 | $Text::Wrap::columns = 80; |
93 | |
94 | @ISA = 'Exporter'; |
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95 | |
96 | %EXPORT_TAGS = ( 'all' => [ qw( |
97 | XS_constant constant_types return_clause memEQ_clause C_stringify |
98 | C_constant autoload |
99 | ) ] ); |
100 | |
101 | @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } ); |
102 | |
103 | %XS_Constant = ( |
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104 | IV => 'PUSHi(iv)', |
105 | UV => 'PUSHu((UV)iv)', |
106 | NV => 'PUSHn(nv)', |
107 | PV => 'PUSHp(pv, strlen(pv))', |
108 | PVN => 'PUSHp(pv, iv)', |
109 | SV => 'PUSHs(sv)', |
110 | YES => 'PUSHs(&PL_sv_yes)', |
111 | NO => 'PUSHs(&PL_sv_no)', |
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112 | UNDEF => '', # implicit undef |
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113 | ); |
114 | |
115 | %XS_TypeSet = ( |
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116 | IV => '*iv_return =', |
117 | UV => '*iv_return = (IV)', |
118 | NV => '*nv_return =', |
119 | PV => '*pv_return =', |
120 | PVN => ['*pv_return =', '*iv_return = (IV)'], |
121 | SV => '*sv_return = ', |
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122 | YES => undef, |
123 | NO => undef, |
124 | UNDEF => undef, |
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125 | ); |
126 | |
127 | |
128 | =item C_stringify NAME |
129 | |
130 | A function which returns a correctly \ escaped version of the string passed |
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131 | suitable for C's "" or ''. It will also be valid as a perl "" string. |
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132 | |
133 | =cut |
134 | |
135 | # Hopefully make a happy C identifier. |
136 | sub C_stringify { |
137 | local $_ = shift; |
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138 | return unless defined $_; |
af6c647e |
139 | s/\\/\\\\/g; |
140 | s/([\"\'])/\\$1/g; # Grr. fix perl mode. |
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141 | s/\n/\\n/g; # Ensure newlines don't end up in octal |
142 | s/\r/\\r/g; |
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143 | s/\t/\\t/g; |
144 | s/\f/\\f/g; |
145 | s/\a/\\a/g; |
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146 | s/([[:cntrl:]])/sprintf "\\%03o", ord $1/ge; |
147 | s/\177/\\177/g; # DEL doesn't seem to be a [:cntrl:] |
148 | $_; |
149 | } |
150 | |
151 | =item constant_types |
152 | |
153 | A function returning a single scalar with C<#define> definitions for the |
154 | constants used internally between the generated C and XS functions. |
155 | |
156 | =cut |
157 | |
158 | sub constant_types () { |
159 | my $start = 1; |
160 | my @lines; |
161 | push @lines, "#define PERL_constant_NOTFOUND\t$start\n"; $start++; |
162 | push @lines, "#define PERL_constant_NOTDEF\t$start\n"; $start++; |
163 | foreach (sort keys %XS_Constant) { |
164 | push @lines, "#define PERL_constant_IS$_\t$start\n"; $start++; |
165 | } |
166 | push @lines, << 'EOT'; |
167 | |
168 | #ifndef NVTYPE |
169 | typedef double NV; /* 5.6 and later define NVTYPE, and typedef NV to it. */ |
170 | #endif |
171 | EOT |
172 | |
173 | return join '', @lines; |
174 | } |
175 | |
176 | =item memEQ_clause NAME, CHECKED_AT, INDENT |
177 | |
178 | A function to return a suitable C C<if> statement to check whether I<NAME> |
179 | is equal to the C variable C<name>. If I<CHECKED_AT> is defined, then it |
180 | is used to avoid C<memEQ> for short names, or to generate a comment to |
181 | highlight the position of the character in the C<switch> statement. |
182 | |
183 | =cut |
184 | |
185 | sub memEQ_clause { |
186 | # if (memEQ(name, "thingy", 6)) { |
187 | # Which could actually be a character comparison or even "" |
188 | my ($name, $checked_at, $indent) = @_; |
189 | $indent = ' ' x ($indent || 4); |
190 | my $len = length $name; |
191 | |
192 | if ($len < 2) { |
193 | return $indent . "{\n" if (defined $checked_at and $checked_at == 0); |
194 | # We didn't switch, drop through to the code for the 2 character string |
195 | $checked_at = 1; |
196 | } |
197 | if ($len < 3 and defined $checked_at) { |
198 | my $check; |
199 | if ($checked_at == 1) { |
200 | $check = 0; |
201 | } elsif ($checked_at == 0) { |
202 | $check = 1; |
203 | } |
204 | if (defined $check) { |
205 | my $char = C_stringify (substr $name, $check, 1); |
206 | return $indent . "if (name[$check] == '$char') {\n"; |
207 | } |
208 | } |
209 | # Could optimise a memEQ on 3 to 2 single character checks here |
210 | $name = C_stringify ($name); |
211 | my $body = $indent . "if (memEQ(name, \"$name\", $len)) {\n"; |
212 | $body .= $indent . "/* ". (' ' x $checked_at) . '^' |
213 | . (' ' x ($len - $checked_at + length $len)) . " */\n" |
214 | if defined $checked_at; |
215 | return $body; |
216 | } |
217 | |
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218 | =item assign INDENT, TYPE, PRE, POST, VALUE... |
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219 | |
220 | A function to return a suitable assignment clause. If I<TYPE> is aggregate |
221 | (eg I<PVN> expects both pointer and length) then there should be multiple |
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222 | I<VALUE>s for the components. I<PRE> and I<POST> if defined give snippets |
223 | of C code to preceed and follow the assignment. I<PRE> will be at the start |
224 | of a block, so variables may be defined in it. |
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225 | |
226 | =cut |
227 | |
228 | # Hmm. value undef to to NOTDEF? value () to do NOTFOUND? |
229 | |
230 | sub assign { |
231 | my $indent = shift; |
232 | my $type = shift; |
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233 | my $pre = shift; |
234 | my $post = shift || ''; |
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235 | my $clause; |
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236 | my $close; |
237 | if ($pre) { |
238 | chomp $pre; |
239 | $clause = $indent . "{\n$pre"; |
240 | $clause .= ";" unless $pre =~ /;$/; |
241 | $clause .= "\n"; |
242 | $close = "$indent}\n"; |
243 | $indent .= " "; |
244 | } |
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245 | die "Can't generate code for type $type" unless exists $XS_TypeSet{$type}; |
246 | my $typeset = $XS_TypeSet{$type}; |
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247 | if (ref $typeset) { |
248 | die "Type $type is aggregate, but only single value given" |
249 | if @_ == 1; |
250 | foreach (0 .. $#$typeset) { |
251 | $clause .= $indent . "$typeset->[$_] $_[$_];\n"; |
252 | } |
3414cef0 |
253 | } elsif (defined $typeset) { |
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254 | die "Aggregate value given for type $type" |
255 | if @_ > 1; |
256 | $clause .= $indent . "$typeset $_[0];\n"; |
257 | } |
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258 | chomp $post; |
259 | if (length $post) { |
260 | $clause .= "$post"; |
261 | $clause .= ";" unless $post =~ /;$/; |
262 | $clause .= "\n"; |
263 | } |
6d79cad2 |
264 | $clause .= "${indent}return PERL_constant_IS$type;\n"; |
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265 | $clause .= $close if $close; |
6d79cad2 |
266 | return $clause; |
267 | } |
268 | |
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269 | =item return_clause VALUE, TYPE, INDENT, MACRO, DEFAULT, PRE, POST, PRE, POST |
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270 | |
271 | A function to return a suitable C<#ifdef> clause. I<MACRO> defaults to |
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272 | I<VALUE> when not defined. If I<TYPE> is aggregate (eg I<PVN> expects both |
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273 | pointer and length) then I<VALUE> should be a reference to an array of |
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274 | values in the order expected by the type. C<C_constant> will always call |
275 | this function with I<MACRO> defined, defaulting to the constant's name. |
276 | I<DEFAULT> if defined is an array reference giving default type and and |
277 | value(s) if the clause generated by I<MACRO> doesn't evaluate to true. |
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278 | The two pairs I<PRE> and I<POST> if defined give C code snippets to proceed |
279 | and follow the value, and the default value. |
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280 | |
281 | =cut |
282 | |
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283 | sub return_clause ($$$$$$$$$) { |
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284 | ##ifdef thingy |
285 | # *iv_return = thingy; |
286 | # return PERL_constant_ISIV; |
287 | ##else |
288 | # return PERL_constant_NOTDEF; |
289 | ##endif |
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290 | my ($value, $type, $indent, $macro, $default, $pre, $post, |
291 | $def_pre, $def_post) = @_; |
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292 | $macro = $value unless defined $macro; |
293 | $indent = ' ' x ($indent || 6); |
294 | |
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295 | my $clause; |
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296 | |
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297 | ##ifdef thingy |
298 | if (ref $macro) { |
299 | $clause = $macro->[0]; |
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300 | } else { |
6d79cad2 |
301 | $clause = "#ifdef $macro\n"; |
af6c647e |
302 | } |
6d79cad2 |
303 | |
304 | # *iv_return = thingy; |
305 | # return PERL_constant_ISIV; |
cea00dc5 |
306 | $clause .= assign ($indent, $type, $pre, $post, |
307 | ref $value ? @$value : $value); |
6d79cad2 |
308 | |
309 | ##else |
310 | $clause .= "#else\n"; |
311 | |
312 | # return PERL_constant_NOTDEF; |
313 | if (!defined $default) { |
314 | $clause .= "${indent}return PERL_constant_NOTDEF;\n"; |
315 | } else { |
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316 | my @default = ref $default ? @$default : $default; |
317 | $type = shift @default; |
318 | $clause .= assign ($indent, $type, $def_pre, $def_post, @default); |
6d79cad2 |
319 | } |
320 | |
321 | ##endif |
322 | if (ref $macro) { |
323 | $clause .= $macro->[1]; |
324 | } else { |
325 | $clause .= "#endif\n"; |
326 | } |
327 | return $clause |
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328 | } |
329 | |
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330 | =item switch_clause INDENT, NAMELEN, ITEMHASH, ITEM... |
331 | |
332 | An internal function to generate a suitable C<switch> clause, called by |
333 | C<C_constant> I<ITEM>s are in the hash ref format as given in the description |
334 | of C<C_constant>, and must all have the names of the same length, given by |
335 | I<NAMELEN> (This is not checked). I<ITEMHASH> is a reference to a hash, |
336 | keyed by name, values being the hashrefs in the I<ITEM> list. |
337 | (No parameters are modified, and there can be keys in the I<ITEMHASH> that |
338 | are not in the list of I<ITEM>s without causing problems). |
339 | |
340 | =cut |
341 | |
342 | sub switch_clause { |
343 | my ($indent, $comment, $namelen, $items, @items) = @_; |
344 | $indent = ' ' x ($indent || 2); |
345 | |
346 | my @names = sort map {$_->{name}} @items; |
347 | my $leader = $indent . '/* '; |
348 | my $follower = ' ' x length $leader; |
349 | my $body = $indent . "/* Names all of length $namelen. */\n"; |
350 | if ($comment) { |
351 | $body = wrap ($leader, $follower, $comment) . "\n"; |
352 | $leader = $follower; |
353 | } |
354 | $body .= wrap ($leader, $follower, join (" ", @names) . " */") . "\n"; |
355 | # Figure out what to switch on. |
356 | # (RMS, Spread of jump table, Position, Hashref) |
357 | my @best = (1e38, ~0); |
358 | foreach my $i (0 .. ($namelen - 1)) { |
359 | my ($min, $max) = (~0, 0); |
360 | my %spread; |
361 | foreach (@names) { |
362 | my $char = substr $_, $i, 1; |
363 | my $ord = ord $char; |
364 | $max = $ord if $ord > $max; |
365 | $min = $ord if $ord < $min; |
366 | push @{$spread{$char}}, $_; |
367 | # warn "$_ $char"; |
368 | } |
369 | # I'm going to pick the character to split on that minimises the root |
370 | # mean square of the number of names in each case. Normally this should |
371 | # be the one with the most keys, but it may pick a 7 where the 8 has |
372 | # one long linear search. I'm not sure if RMS or just sum of squares is |
373 | # actually better. |
374 | # $max and $min are for the tie-breaker if the root mean squares match. |
375 | # Assuming that the compiler may be building a jump table for the |
376 | # switch() then try to minimise the size of that jump table. |
377 | # Finally use < not <= so that if it still ties the earliest part of |
378 | # the string wins. Because if that passes but the memEQ fails, it may |
379 | # only need the start of the string to bin the choice. |
380 | # I think. But I'm micro-optimising. :-) |
381 | my $ss; |
382 | $ss += @$_ * @$_ foreach values %spread; |
383 | my $rms = sqrt ($ss / keys %spread); |
384 | if ($rms < $best[0] || ($rms == $best[0] && ($max - $min) < $best[1])) { |
385 | @best = ($rms, $max - $min, $i, \%spread); |
386 | } |
387 | } |
388 | die "Internal error. Failed to pick a switch point for @names" |
389 | unless defined $best[2]; |
390 | # use Data::Dumper; print Dumper (@best); |
391 | my ($offset, $best) = @best[2,3]; |
392 | $body .= $indent . "/* Offset $offset gives the best switch position. */\n"; |
393 | $body .= $indent . "switch (name[$offset]) {\n"; |
394 | foreach my $char (sort keys %$best) { |
395 | $body .= $indent . "case '" . C_stringify ($char) . "':\n"; |
396 | foreach my $name (sort @{$best->{$char}}) { |
397 | my $thisone = $items->{$name}; |
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398 | my ($value, $macro, $default, $pre, $post, $def_pre, $def_post) |
399 | = @$thisone{qw (value macro default pre post def_pre def_post)}; |
8ac27563 |
400 | $value = $name unless defined $value; |
401 | $macro = $name unless defined $macro; |
402 | |
403 | # We have checked this offset. |
404 | $body .= memEQ_clause ($name, $offset, 2 + length $indent); |
405 | $body .= return_clause ($value, $thisone->{type}, 4 + length $indent, |
cea00dc5 |
406 | $macro, $default, $pre, $post, |
407 | $def_pre, $def_post); |
8ac27563 |
408 | $body .= $indent . " }\n"; |
409 | } |
410 | $body .= $indent . " break;\n"; |
411 | } |
412 | $body .= $indent . "}\n"; |
413 | return $body; |
414 | } |
415 | |
af6c647e |
416 | =item params WHAT |
417 | |
418 | An internal function. I<WHAT> should be a hashref of types the constant |
419 | function will return. I<params> returns the list of flags C<$use_iv, $use_nv, |
420 | $use_pv> to show which combination of pointers will be needed in the C |
421 | argument list. |
422 | |
423 | =cut |
424 | |
425 | sub params { |
426 | my $what = shift; |
427 | foreach (sort keys %$what) { |
428 | warn "ExtUtils::Constant doesn't know how to handle values of type $_" unless defined $XS_Constant{$_}; |
429 | } |
430 | my $use_iv = $what->{IV} || $what->{UV} || $what->{PVN}; |
431 | my $use_nv = $what->{NV}; |
432 | my $use_pv = $what->{PV} || $what->{PVN}; |
cea00dc5 |
433 | my $use_sv = $what->{SV}; |
434 | return ($use_iv, $use_nv, $use_pv, $use_sv); |
af6c647e |
435 | } |
436 | |
0addb26a |
437 | =item dump_names |
438 | |
8ac27563 |
439 | dump_names PACKAGE, SUBNAME, DEFAULT_TYPE, TYPES, INDENT, BREAKOUT, ITEM... |
6d79cad2 |
440 | |
441 | An internal function to generate the embedded perl code that will regenerate |
8ac27563 |
442 | the constant subroutines. Parameters are the same as for C_constant. |
6d79cad2 |
443 | |
444 | =cut |
445 | |
446 | sub dump_names { |
8ac27563 |
447 | my ($package, $subname, $default_type, $what, $indent, $breakout, @items) |
448 | = @_; |
6d79cad2 |
449 | my (@simple, @complex); |
450 | foreach (@items) { |
451 | my $type = $_->{type} || $default_type; |
452 | if ($type eq $default_type and 0 == ($_->{name} =~ tr/A-Za-z0-9_//c) |
453 | and !defined ($_->{macro}) and !defined ($_->{value}) |
cea00dc5 |
454 | and !defined ($_->{default}) and !defined ($_->{pre}) |
455 | and !defined ($_->{post}) and !defined ($_->{def_pre}) |
456 | and !defined ($_->{def_post})) { |
6d79cad2 |
457 | # It's the default type, and the name consists only of A-Za-z0-9_ |
458 | push @simple, $_->{name}; |
459 | } else { |
460 | push @complex, $_; |
461 | } |
462 | } |
463 | my $result = <<"EOT"; |
464 | /* When generated this function returned values for the list of names given |
465 | in this section of perl code. Rather than manually editing these functions |
466 | to add or remove constants, which would result in this comment and section |
467 | of code becoming inaccurate, we recommend that you edit this section of |
468 | code, and use it to regenerate a new set of constant functions which you |
469 | then use to replace the originals. |
470 | |
471 | Regenerate these constant functions by feeding this entire source file to |
472 | perl -x |
473 | |
474 | #!$^X -w |
475 | use ExtUtils::Constant qw (constant_types C_constant XS_constant); |
476 | |
477 | EOT |
8ac27563 |
478 | $result .= 'my $types = {map {($_, 1)} qw(' . join (" ", sort keys %$what) |
479 | . ")};\n"; |
6d79cad2 |
480 | $result .= wrap ("my \@names = (qw(", |
481 | " ", join (" ", sort @simple) . ")"); |
482 | if (@complex) { |
483 | foreach my $item (sort {$a->{name} cmp $b->{name}} @complex) { |
484 | my $name = C_stringify $item->{name}; |
6d79cad2 |
485 | my $line = ",\n {name=>\"$name\""; |
486 | $line .= ", type=>\"$item->{type}\"" if defined $item->{type}; |
cea00dc5 |
487 | foreach my $thing (qw (macro value default pre post def_pre def_post)) { |
488 | my $value = $item->{$thing}; |
489 | if (defined $value) { |
490 | if (ref $value) { |
491 | $line .= ", $thing=>[\"" |
492 | . join ('", "', map {C_stringify $_} @$value) . '"]'; |
493 | } else { |
494 | $line .= ", $thing=>\"" . C_stringify($value) . "\""; |
495 | } |
6d79cad2 |
496 | } |
497 | } |
498 | $line .= "}"; |
499 | # Ensure that the enclosing C comment doesn't end |
500 | # by turning */ into *" . "/ |
501 | $line =~ s!\*\/!\*" . "/!gs; |
3414cef0 |
502 | # gcc -Wall doesn't like finding /* inside a comment |
503 | $line =~ s!\/\*!/" . "\*!gs; |
6d79cad2 |
504 | $result .= $line; |
505 | } |
506 | } |
507 | $result .= ");\n"; |
508 | |
509 | $result .= <<'EOT'; |
510 | |
511 | print constant_types(); # macro defs |
512 | EOT |
513 | $package = C_stringify($package); |
514 | $result .= |
515 | "foreach (C_constant (\"$package\", '$subname', '$default_type', \$types, "; |
516 | # The form of the indent parameter isn't defined. (Yet) |
517 | if (defined $indent) { |
518 | require Data::Dumper; |
519 | $Data::Dumper::Terse=1; |
8ac27563 |
520 | $Data::Dumper::Terse=1; # Not used once. :-) |
6d79cad2 |
521 | chomp ($indent = Data::Dumper::Dumper ($indent)); |
522 | $result .= $indent; |
523 | } else { |
524 | $result .= 'undef'; |
525 | } |
8ac27563 |
526 | $result .= ", $breakout" . ', @names) ) { |
6d79cad2 |
527 | print $_, "\n"; # C constant subs |
528 | } |
529 | print "#### XS Section:\n"; |
530 | print XS_constant ("' . $package . '", $types); |
531 | __END__ |
532 | */ |
533 | |
534 | '; |
535 | |
536 | $result; |
537 | } |
538 | |
0addb26a |
539 | =item C_constant |
540 | |
8ac27563 |
541 | C_constant PACKAGE, SUBNAME, DEFAULT_TYPE, TYPES, INDENT, BREAKOUT, ITEM... |
af6c647e |
542 | |
543 | A function that returns a B<list> of C subroutine definitions that return |
544 | the value and type of constants when passed the name by the XS wrapper. |
545 | I<ITEM...> gives a list of constant names. Each can either be a string, |
546 | which is taken as a C macro name, or a reference to a hash with the following |
547 | keys |
548 | |
549 | =over 8 |
550 | |
551 | =item name |
552 | |
553 | The name of the constant, as seen by the perl code. |
554 | |
555 | =item type |
556 | |
557 | The type of the constant (I<IV>, I<NV> etc) |
558 | |
559 | =item value |
560 | |
561 | A C expression for the value of the constant, or a list of C expressions if |
562 | the type is aggregate. This defaults to the I<name> if not given. |
563 | |
564 | =item macro |
565 | |
566 | The C pre-processor macro to use in the C<#ifdef>. This defaults to the |
6d79cad2 |
567 | I<name>, and is mainly used if I<value> is an C<enum>. If a reference an |
568 | array is passed then the first element is used in place of the C<#ifdef> |
569 | line, and the second element in place of the C<#endif>. This allows |
570 | pre-processor constructions such as |
571 | |
572 | #if defined (foo) |
573 | #if !defined (bar) |
574 | ... |
575 | #endif |
576 | #endif |
577 | |
578 | to be used to determine if a constant is to be defined. |
579 | |
580 | =item default |
581 | |
582 | Default value to use (instead of C<croak>ing with "your vendor has not |
583 | defined...") to return if the macro isn't defined. Specify a reference to |
584 | an array with type followed by value(s). |
af6c647e |
585 | |
cea00dc5 |
586 | =item pre |
587 | |
588 | C code to use before the assignment of the value of the constant. This allows |
589 | you to use temporary variables to extract a value from part of a C<struct> |
590 | and return this as I<value>. This C code is places at the start of a block, |
591 | so you can declare variables in it. |
592 | |
593 | =item post |
594 | |
595 | C code to place between the assignment of value (to a temporary) and the |
596 | return from the function. This allows you to clear up anything in I<pre>. |
597 | Rarely needed. |
598 | |
599 | =item def_pre |
600 | =item def_post |
601 | |
602 | Equivalents of I<pre> and I<post> for the default value. |
603 | |
af6c647e |
604 | =back |
605 | |
6d79cad2 |
606 | I<PACKAGE> is the name of the package, and is only used in comments inside the |
607 | generated C code. |
608 | |
609 | The next 5 arguments can safely be given as C<undef>, and are mainly used |
af6c647e |
610 | for recursion. I<SUBNAME> defaults to C<constant> if undefined. |
611 | |
612 | I<DEFAULT_TYPE> is the type returned by C<ITEM>s that don't specify their |
613 | type. In turn it defaults to I<IV>. I<TYPES> should be given either as a comma |
614 | separated list of types that the C subroutine C<constant> will generate or as |
615 | a reference to a hash. I<DEFAULT_TYPE> will be added to the list if not |
616 | present, as will any types given in the list of I<ITEM>s. The resultant list |
617 | should be the same list of types that C<XS_constant> is given. [Otherwise |
618 | C<XS_constant> and C<C_constant> may differ in the number of parameters to the |
619 | constant function. I<INDENT> is currently unused and ignored. In future it may |
620 | be used to pass in information used to change the C indentation style used.] |
621 | The best way to maintain consistency is to pass in a hash reference and let |
622 | this function update it. |
623 | |
8ac27563 |
624 | I<BREAKOUT> governs when child functions of I<SUBNAME> are generated. If there |
625 | are I<BREAKOUT> or more I<ITEM>s with the same length of name, then the code |
626 | to switch between them is placed into a function named I<SUBNAME>_I<LEN>, for |
627 | example C<constant_5> for names 5 characters long. The default I<BREAKOUT> is |
628 | 3. A single C<ITEM> is always inlined. |
af6c647e |
629 | |
630 | =cut |
631 | |
8ac27563 |
632 | # The parameter now BREAKOUT was previously documented as: |
633 | # |
634 | # I<NAMELEN> if defined signals that all the I<name>s of the I<ITEM>s are of |
635 | # this length, and that the constant name passed in by perl is checked and |
636 | # also of this length. It is used during recursion, and should be C<undef> |
637 | # unless the caller has checked all the lengths during code generation, and |
638 | # the generated subroutine is only to be called with a name of this length. |
639 | # |
640 | # As you can see it now performs this function during recursion by being a |
641 | # scalar reference. |
642 | |
af6c647e |
643 | sub C_constant { |
8ac27563 |
644 | my ($package, $subname, $default_type, $what, $indent, $breakout, @items) |
645 | = @_; |
646 | my $namelen; |
647 | if (ref $breakout) { |
648 | $namelen = $$breakout; |
649 | } else { |
650 | $breakout ||= 3; |
651 | } |
6d79cad2 |
652 | $package ||= 'Foo'; |
af6c647e |
653 | $subname ||= 'constant'; |
654 | # I'm not using this. But a hashref could be used for full formatting without |
655 | # breaking this API |
6d79cad2 |
656 | # $indent ||= 0; |
af6c647e |
657 | $default_type ||= 'IV'; |
658 | if (!ref $what) { |
659 | # Convert line of the form IV,UV,NV to hash |
660 | $what = {map {$_ => 1} split /,\s*/, ($what || '')}; |
661 | # Figure out what types we're dealing with, and assign all unknowns to the |
662 | # default type |
663 | } |
664 | my %items; |
665 | foreach (@items) { |
666 | my $name; |
667 | if (ref $_) { |
cea00dc5 |
668 | my $orig = $_; |
6d79cad2 |
669 | # Make a copy which is a normalised version of the ref passed in. |
af6c647e |
670 | $name = $_->{name}; |
cea00dc5 |
671 | my ($type, $macro, $value) = @$_{qw (type macro value)}; |
6d79cad2 |
672 | $type ||= $default_type; |
673 | $what->{$type} = 1; |
674 | $_ = {name=>$name, type=>$type}; |
675 | |
676 | undef $macro if defined $macro and $macro eq $name; |
677 | $_->{macro} = $macro if defined $macro; |
678 | undef $value if defined $value and $value eq $name; |
679 | $_->{value} = $value if defined $value; |
cea00dc5 |
680 | foreach my $key (qw(default pre post def_pre def_post)) { |
681 | my $value = $orig->{$key}; |
682 | $_->{$key} = $value if defined $value; |
683 | # warn "$key $value"; |
684 | } |
af6c647e |
685 | } else { |
686 | $name = $_; |
687 | $_ = {name=>$_, type=>$default_type}; |
688 | $what->{$default_type} = 1; |
689 | } |
690 | warn "ExtUtils::Constant doesn't know how to handle values of type $_ used in macro $name" unless defined $XS_Constant{$_->{type}}; |
691 | if (exists $items{$name}) { |
692 | die "Multiple definitions for macro $name"; |
693 | } |
694 | $items{$name} = $_; |
695 | } |
cea00dc5 |
696 | my ($use_iv, $use_nv, $use_pv, $use_sv) = params ($what); |
af6c647e |
697 | |
698 | my ($body, @subs) = "static int\n$subname (const char *name"; |
699 | $body .= ", STRLEN len" unless defined $namelen; |
700 | $body .= ", IV *iv_return" if $use_iv; |
701 | $body .= ", NV *nv_return" if $use_nv; |
702 | $body .= ", const char **pv_return" if $use_pv; |
cea00dc5 |
703 | $body .= ", SV **sv_return" if $use_sv; |
af6c647e |
704 | $body .= ") {\n"; |
705 | |
6d79cad2 |
706 | if (defined $namelen) { |
707 | # We are a child subroutine. Print the simple description |
8ac27563 |
708 | my $comment = 'When generated this function returned values for the list' |
709 | . ' of names given here. However, subsequent manual editing may have' |
710 | . ' added or removed some.'; |
711 | $body .= switch_clause (2, $comment, $namelen, \%items, @items); |
af6c647e |
712 | } else { |
713 | # We are the top level. |
714 | $body .= " /* Initially switch on the length of the name. */\n"; |
6d79cad2 |
715 | $body .= dump_names ($package, $subname, $default_type, $what, $indent, |
8ac27563 |
716 | $breakout, @items); |
af6c647e |
717 | $body .= " switch (len) {\n"; |
718 | # Need to group names of the same length |
719 | my @by_length; |
720 | foreach (@items) { |
721 | push @{$by_length[length $_->{name}]}, $_; |
722 | } |
723 | foreach my $i (0 .. $#by_length) { |
724 | next unless $by_length[$i]; # None of this length |
725 | $body .= " case $i:\n"; |
726 | if (@{$by_length[$i]} == 1) { |
727 | my $thisone = $by_length[$i]->[0]; |
cea00dc5 |
728 | my ($name, $value, $macro, $default, $pre, $post, $def_pre, $def_post) |
729 | = @$thisone{qw (name value macro default pre post def_pre def_post)}; |
af6c647e |
730 | $value = $name unless defined $value; |
731 | $macro = $name unless defined $macro; |
732 | |
733 | $body .= memEQ_clause ($name); |
6d79cad2 |
734 | $body .= return_clause ($value, $thisone->{type}, undef, $macro, |
cea00dc5 |
735 | $default, $pre, $post, $def_pre, $def_post); |
af6c647e |
736 | $body .= " }\n"; |
8ac27563 |
737 | } elsif (@{$by_length[$i]} < $breakout) { |
738 | $body .= switch_clause (4, '', $i, \%items, @{$by_length[$i]}); |
af6c647e |
739 | } else { |
6d79cad2 |
740 | push @subs, C_constant ($package, "${subname}_$i", $default_type, |
8ac27563 |
741 | $what, $indent, \$i, @{$by_length[$i]}); |
af6c647e |
742 | $body .= " return ${subname}_$i (name"; |
743 | $body .= ", iv_return" if $use_iv; |
744 | $body .= ", nv_return" if $use_nv; |
745 | $body .= ", pv_return" if $use_pv; |
cea00dc5 |
746 | $body .= ", sv_return" if $use_sv; |
af6c647e |
747 | $body .= ");\n"; |
748 | } |
749 | $body .= " break;\n"; |
750 | } |
751 | $body .= " }\n"; |
752 | } |
753 | $body .= " return PERL_constant_NOTFOUND;\n}\n"; |
754 | return (@subs, $body); |
755 | } |
756 | |
757 | =item XS_constant PACKAGE, TYPES, SUBNAME, C_SUBNAME |
758 | |
759 | A function to generate the XS code to implement the perl subroutine |
760 | I<PACKAGE>::constant used by I<PACKAGE>::AUTOLOAD to load constants. |
761 | This XS code is a wrapper around a C subroutine usually generated by |
762 | C<C_constant>, and usually named C<constant>. |
763 | |
764 | I<TYPES> should be given either as a comma separated list of types that the |
765 | C subroutine C<constant> will generate or as a reference to a hash. It should |
766 | be the same list of types as C<C_constant> was given. |
767 | [Otherwise C<XS_constant> and C<C_constant> may have different ideas about |
768 | the number of parameters passed to the C function C<constant>] |
769 | |
770 | You can call the perl visible subroutine something other than C<constant> if |
771 | you give the parameter I<SUBNAME>. The C subroutine it calls defaults to the |
772 | the name of the perl visible subroutine, unless you give the parameter |
773 | I<C_SUBNAME>. |
774 | |
775 | =cut |
776 | |
777 | sub XS_constant { |
778 | my $package = shift; |
779 | my $what = shift; |
780 | my $subname = shift; |
781 | my $C_subname = shift; |
782 | $subname ||= 'constant'; |
783 | $C_subname ||= $subname; |
784 | |
785 | if (!ref $what) { |
786 | # Convert line of the form IV,UV,NV to hash |
787 | $what = {map {$_ => 1} split /,\s*/, ($what)}; |
788 | } |
cea00dc5 |
789 | my ($use_iv, $use_nv, $use_pv, $use_sv) = params ($what); |
af6c647e |
790 | my $type; |
791 | |
792 | my $xs = <<"EOT"; |
793 | void |
794 | $subname(sv) |
795 | PREINIT: |
796 | #ifdef dXSTARG |
797 | dXSTARG; /* Faster if we have it. */ |
798 | #else |
799 | dTARGET; |
800 | #endif |
801 | STRLEN len; |
802 | int type; |
803 | EOT |
804 | |
805 | if ($use_iv) { |
806 | $xs .= " IV iv;\n"; |
807 | } else { |
808 | $xs .= " /* IV\t\tiv;\tUncomment this if you need to return IVs */\n"; |
809 | } |
810 | if ($use_nv) { |
811 | $xs .= " NV nv;\n"; |
812 | } else { |
813 | $xs .= " /* NV\t\tnv;\tUncomment this if you need to return NVs */\n"; |
814 | } |
815 | if ($use_pv) { |
816 | $xs .= " const char *pv;\n"; |
817 | } else { |
818 | $xs .= |
819 | " /* const char\t*pv;\tUncomment this if you need to return PVs */\n"; |
820 | } |
821 | |
822 | $xs .= << 'EOT'; |
823 | INPUT: |
824 | SV * sv; |
825 | const char * s = SvPV(sv, len); |
826 | PPCODE: |
827 | EOT |
828 | |
829 | if ($use_iv xor $use_nv) { |
830 | $xs .= << "EOT"; |
831 | /* Change this to $C_subname(s, len, &iv, &nv); |
832 | if you need to return both NVs and IVs */ |
833 | EOT |
834 | } |
835 | $xs .= " type = $C_subname(s, len"; |
836 | $xs .= ', &iv' if $use_iv; |
837 | $xs .= ', &nv' if $use_nv; |
838 | $xs .= ', &pv' if $use_pv; |
cea00dc5 |
839 | $xs .= ', &sv' if $use_sv; |
af6c647e |
840 | $xs .= ");\n"; |
841 | |
842 | $xs .= << "EOT"; |
843 | /* Return 1 or 2 items. First is error message, or undef if no error. |
844 | Second, if present, is found value */ |
845 | switch (type) { |
846 | case PERL_constant_NOTFOUND: |
847 | sv = sv_2mortal(newSVpvf("%s is not a valid $package macro", s)); |
6d79cad2 |
848 | PUSHs(sv); |
af6c647e |
849 | break; |
850 | case PERL_constant_NOTDEF: |
851 | sv = sv_2mortal(newSVpvf( |
8ac27563 |
852 | "Your vendor has not defined $package macro %s, used", s)); |
6d79cad2 |
853 | PUSHs(sv); |
af6c647e |
854 | break; |
855 | EOT |
856 | |
857 | foreach $type (sort keys %XS_Constant) { |
858 | $xs .= "\t/* Uncomment this if you need to return ${type}s\n" |
859 | unless $what->{$type}; |
8ac27563 |
860 | $xs .= " case PERL_constant_IS$type:\n"; |
861 | if (length $XS_Constant{$type}) { |
862 | $xs .= << "EOT"; |
af6c647e |
863 | EXTEND(SP, 1); |
864 | PUSHs(&PL_sv_undef); |
865 | $XS_Constant{$type}; |
af6c647e |
866 | EOT |
8ac27563 |
867 | } else { |
868 | # Do nothing. return (), which will be correctly interpreted as |
869 | # (undef, undef) |
870 | } |
871 | $xs .= " break;\n"; |
af6c647e |
872 | unless ($what->{$type}) { |
873 | chop $xs; # Yes, another need for chop not chomp. |
874 | $xs .= " */\n"; |
875 | } |
876 | } |
877 | $xs .= << "EOT"; |
878 | default: |
879 | sv = sv_2mortal(newSVpvf( |
8ac27563 |
880 | "Unexpected return type %d while processing $package macro %s, used", |
af6c647e |
881 | type, s)); |
6d79cad2 |
882 | PUSHs(sv); |
af6c647e |
883 | } |
884 | EOT |
885 | |
886 | return $xs; |
887 | } |
888 | |
889 | |
6d79cad2 |
890 | =item autoload PACKAGE, VERSION, AUTOLOADER |
af6c647e |
891 | |
892 | A function to generate the AUTOLOAD subroutine for the module I<PACKAGE> |
893 | I<VERSION> is the perl version the code should be backwards compatible with. |
6d79cad2 |
894 | It defaults to the version of perl running the subroutine. If I<AUTOLOADER> |
895 | is true, the AUTOLOAD subroutine falls back on AutoLoader::AUTOLOAD for all |
896 | names that the constant() routine doesn't recognise. |
af6c647e |
897 | |
898 | =cut |
899 | |
6d79cad2 |
900 | # ' # Grr. syntax highlighters that don't grok pod. |
901 | |
af6c647e |
902 | sub autoload { |
6d79cad2 |
903 | my ($module, $compat_version, $autoloader) = @_; |
af6c647e |
904 | $compat_version ||= $]; |
905 | croak "Can't maintain compatibility back as far as version $compat_version" |
906 | if $compat_version < 5; |
6d79cad2 |
907 | my $func = "sub AUTOLOAD {\n" |
908 | . " # This AUTOLOAD is used to 'autoload' constants from the constant()\n" |
909 | . " # XS function."; |
910 | $func .= " If a constant is not found then control is passed\n" |
911 | . " # to the AUTOLOAD in AutoLoader." if $autoloader; |
912 | |
913 | |
914 | $func .= "\n\n" |
915 | . " my \$constname;\n"; |
916 | $func .= |
917 | " our \$AUTOLOAD;\n" if ($compat_version >= 5.006); |
918 | |
919 | $func .= <<"EOT"; |
af6c647e |
920 | (\$constname = \$AUTOLOAD) =~ s/.*:://; |
921 | croak "&${module}::constant not defined" if \$constname eq 'constant'; |
922 | my (\$error, \$val) = constant(\$constname); |
6d79cad2 |
923 | EOT |
924 | |
925 | if ($autoloader) { |
926 | $func .= <<'EOT'; |
927 | if ($error) { |
928 | if ($error =~ /is not a valid/) { |
929 | $AutoLoader::AUTOLOAD = $AUTOLOAD; |
af6c647e |
930 | goto &AutoLoader::AUTOLOAD; |
931 | } else { |
6d79cad2 |
932 | croak $error; |
af6c647e |
933 | } |
934 | } |
6d79cad2 |
935 | EOT |
936 | } else { |
937 | $func .= |
938 | " if (\$error) { croak \$error; }\n"; |
939 | } |
940 | |
941 | $func .= <<'END'; |
af6c647e |
942 | { |
943 | no strict 'refs'; |
944 | # Fixed between 5.005_53 and 5.005_61 |
6d79cad2 |
945 | #XXX if ($] >= 5.00561) { |
946 | #XXX *$AUTOLOAD = sub () { $val }; |
af6c647e |
947 | #XXX } |
948 | #XXX else { |
6d79cad2 |
949 | *$AUTOLOAD = sub { $val }; |
af6c647e |
950 | #XXX } |
951 | } |
6d79cad2 |
952 | goto &$AUTOLOAD; |
af6c647e |
953 | } |
954 | |
955 | END |
956 | |
6d79cad2 |
957 | return $func; |
af6c647e |
958 | } |
959 | 1; |
960 | __END__ |
961 | |
962 | =back |
963 | |
964 | =head1 AUTHOR |
965 | |
966 | Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and |
967 | others |
968 | |
969 | =cut |