1 package ExtUtils::XSSymSet;
5 use vars qw( $VERSION );
10 my($pkg,$maxlen,$silent) = @_;
12 # Allow absurdly long symbols here if we've told the compiler to
13 # do the shortening for us.
14 $maxlen = 2048 if $Config{'useshortenedsymbols'};
16 my($obj) = { '__M@xLen' => $maxlen, '__S!lent' => $silent };
22 my($self,$name,$maxlen,$silent) = @_;
24 unless (defined $maxlen) {
25 if (ref $self) { $maxlen ||= $self->{'__M@xLen'}; }
28 $maxlen = 2048 if $Config{'useshortenedsymbols'};
30 unless (defined $silent) {
31 if (ref $self) { $silent ||= $self->{'__S!lent'}; }
34 return $name if (length $name <= $maxlen);
37 # First, just try to remove duplicated delimiters
39 if (length $trimmed > $maxlen) {
40 # Next, all duplicated chars
41 $trimmed =~ s/(.)\1+/$1/g;
42 if (length $trimmed > $maxlen) {
43 my $squeezed = $trimmed;
44 my($xs,$prefix,$func) = $trimmed =~ /^(XS_)?(.*)_([^_]*)$/;
46 my $frac = 3; # replaces broken length-based calculations but w/same result
48 if (length $func <= 12) { # Try to preserve short function names
49 if ($frac > 1) { $pat .= '[^A-Z_]{' . ($frac - 1) . '}'; }
50 $prefix =~ s/$pat/$1/g;
51 $squeezed = "$xs$prefix" . "_$func";
52 if (length $squeezed > $maxlen) {
54 $prefix =~ s/$pat/$1/g;
55 $squeezed = "$xs$prefix" . "_$func";
59 if ($frac > 1) { $pat .= '[^A-Z_]{' . ($frac - 1) . '}'; }
60 $squeezed = "$prefix$func";
61 $squeezed =~ s/$pat/$1/g;
62 if (length "$xs$squeezed" > $maxlen) {
64 $squeezed =~ s/$pat/$1/g;
66 $squeezed = "$xs$squeezed";
68 if (length $squeezed <= $maxlen) { $trimmed = $squeezed; }
70 my $frac = int((length $trimmed - $maxlen) / length $trimmed + 0.5);
71 my $pat = '(.).{$frac}';
72 $trimmed =~ s/$pat/$1/g;
76 warn "Warning: long symbol $name\n\ttrimmed to $trimmed\n\t" unless $silent;
82 my($self,$sym,$maxlen,$silent) = @_;
83 my $trimmed = $self->get_trimmed($sym);
85 return $trimmed if defined $trimmed;
87 $maxlen ||= $self->{'__M@xLen'} || 31;
88 $silent ||= $self->{'__S!lent'} || 0;
89 $trimmed = $self->trimsym($sym,$maxlen,1);
90 if (exists $self->{$trimmed}) {
92 $trimmed = $self->trimsym($sym,$maxlen-3,$silent);
93 while (exists $self->{"${trimmed}_$i"}) { $i++; }
94 warn "Warning: duplicate symbol $trimmed\n\tchanged to ${trimmed}_$i\n\t(original was $sym)\n\t"
98 elsif (not $silent and $trimmed ne $sym) {
99 warn "Warning: long symbol $sym\n\ttrimmed to $trimmed\n\t";
101 $self->{$trimmed} = $sym;
102 $self->{'__N+Map'}->{$sym} = $trimmed;
109 my $trimmed = $self->{'__N+Map'}->{$sym};
110 if (defined $trimmed) {
111 delete $self->{'__N+Map'}->{$sym};
112 delete $self->{$trimmed};
120 $self->{'__N+Map'}->{$sym};
125 my($self,$trimmed) = @_;
130 sub all_orig { (keys %{$_[0]->{'__N+Map'}}); }
131 sub all_trimmed { (grep { /^\w+$/ } keys %{$_[0]}); }
137 ExtUtils::XSSymSet - keep sets of symbol names palatable to the VMS linker
141 use ExtUtils::XSSymSet;
143 $set = new ExtUtils::XSSymSet;
144 while ($sym = make_symbol()) { $set->addsym($sym); }
145 foreach $safesym ($set->all_trimmed) {
146 print "Processing $safesym (derived from ",$self->get_orig($safesym),")\n";
150 $safesym = ExtUtils::XSSymSet->trimsym($onesym);
154 Since the VMS linker distinguishes symbols based only on the first 31
155 characters of their names, it is occasionally necessary to shorten
156 symbol names in order to avoid collisions. (This is especially true of
157 names generated by xsubpp, since prefixes generated by nested package
158 names can become quite long.) C<ExtUtils::XSSymSet> provides functions to
159 shorten names in a consistent fashion, and to track a set of names to
160 insure that each is unique. While designed with F<xsubpp> in mind, it
161 may be used with any set of strings.
163 This package supplies the following functions, all of which should be
168 =item new([$maxlen[,$silent]])
170 Creates an empty C<ExtUtils::XSSymset> set of symbols. This function may be
171 called as a static method or via an existing object. If C<$maxlen> or
172 C<$silent> are specified, they are used as the defaults for maximum
173 name length and warning behavior in future calls to addsym() or
174 trimsym() via this object. If the compiler has been instructed to do its
175 own symbol shortening via C<$Config{'useshortenedsymbols'}>, a value of
176 2048 is assumed for C<$maxlen> as a way of bypassing the shortening done by
179 =item addsym($name[,$maxlen[,$silent]])
181 Creates a symbol name from C<$name>, using the methods described
182 under trimsym(), which is unique in this set of symbols, and returns
183 the new name. C<$name> and its resultant are added to the set, and
184 any future calls to addsym() specifying the same C<$name> will return
185 the same result, regardless of the value of C<$maxlen> specified.
186 Unless C<$silent> is true, warnings are output if C<$name> had to be
187 trimmed or changed in order to avoid collision with an existing symbol
188 name. C<$maxlen> and C<$silent> default to the values specified when
189 this set of symbols was created. This method must be called via an
192 =item trimsym($name[,$maxlen[,$silent]])
194 Creates a symbol name C<$maxlen> or fewer characters long from
195 C<$name> and returns it. If C<$name> is too long, it first tries to
196 shorten it by removing duplicate characters, then by periodically
197 removing non-underscore characters, and finally, if necessary, by
198 periodically removing characters of any type. C<$maxlen> defaults
199 to 31. Unless C<$silent> is true, a warning is output if C<$name>
200 is altered in any way. This function may be called either as a
201 static method or via an existing object, but in the latter case no
202 check is made to insure that the resulting name is unique in the
203 set of symbols. If the compiler has been instructed to do its
204 own symbol shortening via C<$Config{'useshortenedsymbols'}>, a value
205 of 2048 is assumed for C<$maxlen> as a way of bypassing the shortening
210 Removes C<$name> from the set of symbols, where C<$name> is the
211 original symbol name passed previously to addsym(). If C<$name>
212 existed in the set of symbols, returns its "trimmed" equivalent,
213 otherwise returns C<undef>. This method must be called via an
216 =item get_orig($trimmed)
218 Returns the original name which was trimmed to C<$trimmed> by a
219 previous call to addsym(), or C<undef> if C<$trimmed> does not
220 correspond to a member of this set of symbols. This method must be
221 called via an existing object.
223 =item get_trimmed($name)
225 Returns the trimmed name which was generated from C<$name> by a
226 previous call to addsym(), or C<undef> if C<$name> is not a member
227 of this set of symbols. This method must be called via an
232 Returns a list containing all of the original symbol names
237 Returns a list containing all of the trimmed symbol names
244 Charles Bailey E<lt>I<bailey@newman.upenn.edu>E<gt>
248 Last revised 8-Oct-2010, for Perl 5.13.6.