summaryrefslogtreecommitdiff
path: root/Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm
diff options
context:
space:
mode:
Diffstat (limited to 'Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm')
-rw-r--r--Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm1006
1 files changed, 1006 insertions, 0 deletions
diff --git a/Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm b/Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm
new file mode 100644
index 00000000000..b5b79af1ea7
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/ExtUtils/Constant/Base.pm
@@ -0,0 +1,1006 @@
+package ExtUtils::Constant::Base;
+
+use strict;
+use vars qw($VERSION);
+use Carp;
+use Text::Wrap;
+use ExtUtils::Constant::Utils qw(C_stringify perl_stringify);
+$VERSION = '0.04';
+
+use constant is_perl56 => ($] < 5.007 && $] > 5.005_50);
+
+
+=head1 NAME
+
+ExtUtils::Constant::Base - base class for ExtUtils::Constant objects
+
+=head1 SYNOPSIS
+
+ require ExtUtils::Constant::Base;
+ @ISA = 'ExtUtils::Constant::Base';
+
+=head1 DESCRIPTION
+
+ExtUtils::Constant::Base provides a base implementation of methods to
+generate C code to give fast constant value lookup by named string. Currently
+it's mostly used ExtUtils::Constant::XS, which generates the lookup code
+for the constant() subroutine found in many XS modules.
+
+=head1 USAGE
+
+ExtUtils::Constant::Base exports no subroutines. The following methods are
+available
+
+=over 4
+
+=cut
+
+sub valid_type {
+ # Default to assuming that you don't need different types of return data.
+ 1;
+}
+sub default_type {
+ '';
+}
+
+=item header
+
+A method returning a scalar containing definitions needed, typically for a
+C header file.
+
+=cut
+
+sub header {
+ ''
+}
+
+# This might actually be a return statement. Note that you are responsible
+# for any space you might need before your value, as it lets to perform
+# "tricks" such as "return KEY_" and have strings appended.
+sub assignment_clause_for_type;
+# In which case this might be an empty string
+sub return_statement_for_type {undef};
+sub return_statement_for_notdef;
+sub return_statement_for_notfound;
+
+# "#if 1" is true to a C pre-processor
+sub macro_from_name {
+ 1;
+}
+
+sub macro_from_item {
+ 1;
+}
+
+sub macro_to_ifdef {
+ my ($self, $macro) = @_;
+ if (ref $macro) {
+ return $macro->[0];
+ }
+ if (defined $macro && $macro ne "" && $macro ne "1") {
+ return $macro ? "#ifdef $macro\n" : "#if 0\n";
+ }
+ return "";
+}
+
+sub macro_to_endif {
+ my ($self, $macro) = @_;
+
+ if (ref $macro) {
+ return $macro->[1];
+ }
+ if (defined $macro && $macro ne "" && $macro ne "1") {
+ return "#endif\n";
+ }
+ return "";
+}
+
+sub name_param {
+ 'name';
+}
+
+# This is possibly buggy, in that it's not mandatory (below, in the main
+# C_constant parameters, but is expected to exist here, if it's needed)
+# Buggy because if you're definitely pure 8 bit only, and will never be
+# presented with your constants in utf8, the default form of C_constant can't
+# be told not to do the utf8 version.
+
+sub is_utf8_param {
+ 'utf8';
+}
+
+sub memEQ {
+ "!memcmp";
+}
+
+=item memEQ_clause args_hashref
+
+A method to return a suitable C C<if> statement to check whether I<name>
+is equal to the C variable C<name>. If I<checked_at> is defined, then it
+is used to avoid C<memEQ> for short names, or to generate a comment to
+highlight the position of the character in the C<switch> statement.
+
+If i<checked_at> is a reference to a scalar, then instead it gives
+the characters pre-checked at the beginning, (and the number of chars by
+which the C variable name has been advanced. These need to be chopped from
+the front of I<name>).
+
+=cut
+
+sub memEQ_clause {
+# if (memEQ(name, "thingy", 6)) {
+ # Which could actually be a character comparison or even ""
+ my ($self, $args) = @_;
+ my ($name, $checked_at, $indent) = @{$args}{qw(name checked_at indent)};
+ $indent = ' ' x ($indent || 4);
+ my $front_chop;
+ if (ref $checked_at) {
+ # regexp won't work on 5.6.1 without use utf8; in turn that won't work
+ # on 5.005_03.
+ substr ($name, 0, length $$checked_at,) = '';
+ $front_chop = C_stringify ($$checked_at);
+ undef $checked_at;
+ }
+ my $len = length $name;
+
+ if ($len < 2) {
+ return $indent . "{\n"
+ if (defined $checked_at and $checked_at == 0) or $len == 0;
+ # We didn't switch, drop through to the code for the 2 character string
+ $checked_at = 1;
+ }
+
+ my $name_param = $self->name_param;
+
+ if ($len < 3 and defined $checked_at) {
+ my $check;
+ if ($checked_at == 1) {
+ $check = 0;
+ } elsif ($checked_at == 0) {
+ $check = 1;
+ }
+ if (defined $check) {
+ my $char = C_stringify (substr $name, $check, 1);
+ # Placate 5.005 with a break in the string. I can't see a good way of
+ # getting it to not take [ as introducing an array lookup, even with
+ # ${name_param}[$check]
+ return $indent . "if ($name_param" . "[$check] == '$char') {\n";
+ }
+ }
+ if (($len == 2 and !defined $checked_at)
+ or ($len == 3 and defined ($checked_at) and $checked_at == 2)) {
+ my $char1 = C_stringify (substr $name, 0, 1);
+ my $char2 = C_stringify (substr $name, 1, 1);
+ return $indent .
+ "if ($name_param" . "[0] == '$char1' && $name_param" . "[1] == '$char2') {\n";
+ }
+ if (($len == 3 and defined ($checked_at) and $checked_at == 1)) {
+ my $char1 = C_stringify (substr $name, 0, 1);
+ my $char2 = C_stringify (substr $name, 2, 1);
+ return $indent .
+ "if ($name_param" . "[0] == '$char1' && $name_param" . "[2] == '$char2') {\n";
+ }
+
+ my $pointer = '^';
+ my $have_checked_last = defined ($checked_at) && $len == $checked_at + 1;
+ if ($have_checked_last) {
+ # Checked at the last character, so no need to memEQ it.
+ $pointer = C_stringify (chop $name);
+ $len--;
+ }
+
+ $name = C_stringify ($name);
+ my $memEQ = $self->memEQ();
+ my $body = $indent . "if ($memEQ($name_param, \"$name\", $len)) {\n";
+ # Put a little ^ under the letter we checked at
+ # Screws up for non printable and non-7 bit stuff, but that's too hard to
+ # get right.
+ if (defined $checked_at) {
+ $body .= $indent . "/* " . (' ' x length $memEQ)
+ . (' ' x length $name_param)
+ . (' ' x $checked_at) . $pointer
+ . (' ' x ($len - $checked_at + length $len)) . " */\n";
+ } elsif (defined $front_chop) {
+ $body .= $indent . "/* $front_chop"
+ . (' ' x ($len + 1 + length $len)) . " */\n";
+ }
+ return $body;
+}
+
+=item dump_names arg_hashref, ITEM...
+
+An internal function to generate the embedded perl code that will regenerate
+the constant subroutines. I<default_type>, I<types> and I<ITEM>s are the
+same as for C_constant. I<indent> is treated as number of spaces to indent
+by. If C<declare_types> is true a C<$types> is always declared in the perl
+code generated, if defined and false never declared, and if undefined C<$types>
+is only declared if the values in I<types> as passed in cannot be inferred from
+I<default_types> and the I<ITEM>s.
+
+=cut
+
+sub dump_names {
+ my ($self, $args, @items) = @_;
+ my ($default_type, $what, $indent, $declare_types)
+ = @{$args}{qw(default_type what indent declare_types)};
+ $indent = ' ' x ($indent || 0);
+
+ my $result;
+ my (@simple, @complex, %used_types);
+ foreach (@items) {
+ my $type;
+ if (ref $_) {
+ $type = $_->{type} || $default_type;
+ if ($_->{utf8}) {
+ # For simplicity always skip the bytes case, and reconstitute this entry
+ # from its utf8 twin.
+ next if $_->{utf8} eq 'no';
+ # Copy the hashref, as we don't want to mess with the caller's hashref.
+ $_ = {%$_};
+ unless (is_perl56) {
+ utf8::decode ($_->{name});
+ } else {
+ $_->{name} = pack 'U*', unpack 'U0U*', $_->{name};
+ }
+ delete $_->{utf8};
+ }
+ } else {
+ $_ = {name=>$_};
+ $type = $default_type;
+ }
+ $used_types{$type}++;
+ if ($type eq $default_type
+ # grr 5.6.1
+ and length $_->{name}
+ and length $_->{name} == ($_->{name} =~ tr/A-Za-z0-9_//)
+ and !defined ($_->{macro}) and !defined ($_->{value})
+ and !defined ($_->{default}) and !defined ($_->{pre})
+ and !defined ($_->{post}) and !defined ($_->{def_pre})
+ and !defined ($_->{def_post}) and !defined ($_->{weight})) {
+ # It's the default type, and the name consists only of A-Za-z0-9_
+ push @simple, $_->{name};
+ } else {
+ push @complex, $_;
+ }
+ }
+
+ if (!defined $declare_types) {
+ # Do they pass in any types we weren't already using?
+ foreach (keys %$what) {
+ next if $used_types{$_};
+ $declare_types++; # Found one in $what that wasn't used.
+ last; # And one is enough to terminate this loop
+ }
+ }
+ if ($declare_types) {
+ $result = $indent . 'my $types = {map {($_, 1)} qw('
+ . join (" ", sort keys %$what) . ")};\n";
+ }
+ local $Text::Wrap::huge = 'overflow';
+ local $Text::Wrap::columns = 80;
+ $result .= wrap ($indent . "my \@names = (qw(",
+ $indent . " ", join (" ", sort @simple) . ")");
+ if (@complex) {
+ foreach my $item (sort {$a->{name} cmp $b->{name}} @complex) {
+ my $name = perl_stringify $item->{name};
+ my $line = ",\n$indent {name=>\"$name\"";
+ $line .= ", type=>\"$item->{type}\"" if defined $item->{type};
+ foreach my $thing (qw (macro value default pre post def_pre def_post)) {
+ my $value = $item->{$thing};
+ if (defined $value) {
+ if (ref $value) {
+ $line .= ", $thing=>[\""
+ . join ('", "', map {perl_stringify $_} @$value) . '"]';
+ } else {
+ $line .= ", $thing=>\"" . perl_stringify($value) . "\"";
+ }
+ }
+ }
+ $line .= "}";
+ # Ensure that the enclosing C comment doesn't end
+ # by turning */ into *" . "/
+ $line =~ s!\*\/!\*" . "/!gs;
+ # gcc -Wall doesn't like finding /* inside a comment
+ $line =~ s!\/\*!/" . "\*!gs;
+ $result .= $line;
+ }
+ }
+ $result .= ");\n";
+
+ $result;
+}
+
+=item assign arg_hashref, VALUE...
+
+A method to return a suitable assignment clause. If I<type> is aggregate
+(eg I<PVN> expects both pointer and length) then there should be multiple
+I<VALUE>s for the components. I<pre> and I<post> if defined give snippets
+of C code to proceed and follow the assignment. I<pre> will be at the start
+of a block, so variables may be defined in it.
+
+=cut
+# Hmm. value undef to to NOTDEF? value () to do NOTFOUND?
+
+sub assign {
+ my $self = shift;
+ my $args = shift;
+ my ($indent, $type, $pre, $post, $item)
+ = @{$args}{qw(indent type pre post item)};
+ $post ||= '';
+ my $clause;
+ my $close;
+ if ($pre) {
+ chomp $pre;
+ $close = "$indent}\n";
+ $clause = $indent . "{\n";
+ $indent .= " ";
+ $clause .= "$indent$pre";
+ $clause .= ";" unless $pre =~ /;$/;
+ $clause .= "\n";
+ }
+ confess "undef \$type" unless defined $type;
+ confess "Can't generate code for type $type"
+ unless $self->valid_type($type);
+
+ $clause .= join '', map {"$indent$_\n"}
+ $self->assignment_clause_for_type({type=>$type,item=>$item}, @_);
+ chomp $post;
+ if (length $post) {
+ $clause .= "$post";
+ $clause .= ";" unless $post =~ /;$/;
+ $clause .= "\n";
+ }
+ my $return = $self->return_statement_for_type($type);
+ $clause .= "$indent$return\n" if defined $return;
+ $clause .= $close if $close;
+ return $clause;
+}
+
+=item return_clause arg_hashref, ITEM
+
+A method to return a suitable C<#ifdef> clause. I<ITEM> is a hashref
+(as passed to C<C_constant> and C<match_clause>. I<indent> is the number
+of spaces to indent, defaulting to 6.
+
+=cut
+
+sub return_clause {
+
+##ifdef thingy
+# *iv_return = thingy;
+# return PERL_constant_ISIV;
+##else
+# return PERL_constant_NOTDEF;
+##endif
+ my ($self, $args, $item) = @_;
+ my $indent = $args->{indent};
+
+ my ($name, $value, $default, $pre, $post, $def_pre, $def_post, $type)
+ = @$item{qw (name value default pre post def_pre def_post type)};
+ $value = $name unless defined $value;
+ my $macro = $self->macro_from_item($item);
+ $indent = ' ' x ($indent || 6);
+ unless (defined $type) {
+ # use Data::Dumper; print STDERR Dumper ($item);
+ confess "undef \$type";
+ }
+
+ ##ifdef thingy
+ my $clause = $self->macro_to_ifdef($macro);
+
+ # *iv_return = thingy;
+ # return PERL_constant_ISIV;
+ $clause
+ .= $self->assign ({indent=>$indent, type=>$type, pre=>$pre, post=>$post,
+ item=>$item}, ref $value ? @$value : $value);
+
+ if (defined $macro && $macro ne "" && $macro ne "1") {
+ ##else
+ $clause .= "#else\n";
+
+ # return PERL_constant_NOTDEF;
+ if (!defined $default) {
+ my $notdef = $self->return_statement_for_notdef();
+ $clause .= "$indent$notdef\n" if defined $notdef;
+ } else {
+ my @default = ref $default ? @$default : $default;
+ $type = shift @default;
+ $clause .= $self->assign ({indent=>$indent, type=>$type, pre=>$pre,
+ post=>$post, item=>$item}, @default);
+ }
+ }
+ ##endif
+ $clause .= $self->macro_to_endif($macro);
+
+ return $clause;
+}
+
+sub match_clause {
+ # $offset defined if we have checked an offset.
+ my ($self, $args, $item) = @_;
+ my ($offset, $indent) = @{$args}{qw(checked_at indent)};
+ $indent = ' ' x ($indent || 4);
+ my $body = '';
+ my ($no, $yes, $either, $name, $inner_indent);
+ if (ref $item eq 'ARRAY') {
+ ($yes, $no) = @$item;
+ $either = $yes || $no;
+ confess "$item is $either expecting hashref in [0] || [1]"
+ unless ref $either eq 'HASH';
+ $name = $either->{name};
+ } else {
+ confess "$item->{name} has utf8 flag '$item->{utf8}', should be false"
+ if $item->{utf8};
+ $name = $item->{name};
+ $inner_indent = $indent;
+ }
+
+ $body .= $self->memEQ_clause ({name => $name, checked_at => $offset,
+ indent => length $indent});
+ # If we've been presented with an arrayref for $item, then the user string
+ # contains in the range 128-255, and we need to check whether it was utf8
+ # (or not).
+ # In the worst case we have two named constants, where one's name happens
+ # encoded in UTF8 happens to be the same byte sequence as the second's
+ # encoded in (say) ISO-8859-1.
+ # In this case, $yes and $no both have item hashrefs.
+ if ($yes) {
+ $body .= $indent . " if (" . $self->is_utf8_param . ") {\n";
+ } elsif ($no) {
+ $body .= $indent . " if (!" . $self->is_utf8_param . ") {\n";
+ }
+ if ($either) {
+ $body .= $self->return_clause ({indent=>4 + length $indent}, $either);
+ if ($yes and $no) {
+ $body .= $indent . " } else {\n";
+ $body .= $self->return_clause ({indent=>4 + length $indent}, $no);
+ }
+ $body .= $indent . " }\n";
+ } else {
+ $body .= $self->return_clause ({indent=>2 + length $indent}, $item);
+ }
+ $body .= $indent . "}\n";
+}
+
+
+=item switch_clause arg_hashref, NAMELEN, ITEMHASH, ITEM...
+
+An internal method to generate a suitable C<switch> clause, called by
+C<C_constant> I<ITEM>s are in the hash ref format as given in the description
+of C<C_constant>, and must all have the names of the same length, given by
+I<NAMELEN>. I<ITEMHASH> is a reference to a hash, keyed by name, values being
+the hashrefs in the I<ITEM> list. (No parameters are modified, and there can
+be keys in the I<ITEMHASH> that are not in the list of I<ITEM>s without
+causing problems - the hash is passed in to save generating it afresh for
+each call).
+
+=cut
+
+sub switch_clause {
+ my ($self, $args, $namelen, $items, @items) = @_;
+ my ($indent, $comment) = @{$args}{qw(indent comment)};
+ $indent = ' ' x ($indent || 2);
+
+ local $Text::Wrap::huge = 'overflow';
+ local $Text::Wrap::columns = 80;
+
+ my @names = sort map {$_->{name}} @items;
+ my $leader = $indent . '/* ';
+ my $follower = ' ' x length $leader;
+ my $body = $indent . "/* Names all of length $namelen. */\n";
+ if (defined $comment) {
+ $body = wrap ($leader, $follower, $comment) . "\n";
+ $leader = $follower;
+ }
+ my @safe_names = @names;
+ foreach (@safe_names) {
+ confess sprintf "Name '$_' is length %d, not $namelen", length
+ unless length == $namelen;
+ # Argh. 5.6.1
+ # next unless tr/A-Za-z0-9_//c;
+ next if tr/A-Za-z0-9_// == length;
+ $_ = '"' . perl_stringify ($_) . '"';
+ # Ensure that the enclosing C comment doesn't end
+ # by turning */ into *" . "/
+ s!\*\/!\*"."/!gs;
+ # gcc -Wall doesn't like finding /* inside a comment
+ s!\/\*!/"."\*!gs;
+ }
+ $body .= wrap ($leader, $follower, join (" ", @safe_names) . " */") . "\n";
+ # Figure out what to switch on.
+ # (RMS, Spread of jump table, Position, Hashref)
+ my @best = (1e38, ~0);
+ # Prefer the last character over the others. (As it lets us shorten the
+ # memEQ clause at no cost).
+ foreach my $i ($namelen - 1, 0 .. ($namelen - 2)) {
+ my ($min, $max) = (~0, 0);
+ my %spread;
+ if (is_perl56) {
+ # Need proper Unicode preserving hash keys for bytes in range 128-255
+ # here too, for some reason. grr 5.6.1 yet again.
+ tie %spread, 'ExtUtils::Constant::Aaargh56Hash';
+ }
+ foreach (@names) {
+ my $char = substr $_, $i, 1;
+ my $ord = ord $char;
+ confess "char $ord is out of range" if $ord > 255;
+ $max = $ord if $ord > $max;
+ $min = $ord if $ord < $min;
+ push @{$spread{$char}}, $_;
+ # warn "$_ $char";
+ }
+ # I'm going to pick the character to split on that minimises the root
+ # mean square of the number of names in each case. Normally this should
+ # be the one with the most keys, but it may pick a 7 where the 8 has
+ # one long linear search. I'm not sure if RMS or just sum of squares is
+ # actually better.
+ # $max and $min are for the tie-breaker if the root mean squares match.
+ # Assuming that the compiler may be building a jump table for the
+ # switch() then try to minimise the size of that jump table.
+ # Finally use < not <= so that if it still ties the earliest part of
+ # the string wins. Because if that passes but the memEQ fails, it may
+ # only need the start of the string to bin the choice.
+ # I think. But I'm micro-optimising. :-)
+ # OK. Trump that. Now favour the last character of the string, before the
+ # rest.
+ my $ss;
+ $ss += @$_ * @$_ foreach values %spread;
+ my $rms = sqrt ($ss / keys %spread);
+ if ($rms < $best[0] || ($rms == $best[0] && ($max - $min) < $best[1])) {
+ @best = ($rms, $max - $min, $i, \%spread);
+ }
+ }
+ confess "Internal error. Failed to pick a switch point for @names"
+ unless defined $best[2];
+ # use Data::Dumper; print Dumper (@best);
+ my ($offset, $best) = @best[2,3];
+ $body .= $indent . "/* Offset $offset gives the best switch position. */\n";
+
+ my $do_front_chop = $offset == 0 && $namelen > 2;
+ if ($do_front_chop) {
+ $body .= $indent . "switch (*" . $self->name_param() . "++) {\n";
+ } else {
+ $body .= $indent . "switch (" . $self->name_param() . "[$offset]) {\n";
+ }
+ foreach my $char (sort keys %$best) {
+ confess sprintf "'$char' is %d bytes long, not 1", length $char
+ if length ($char) != 1;
+ confess sprintf "char %#X is out of range", ord $char if ord ($char) > 255;
+ $body .= $indent . "case '" . C_stringify ($char) . "':\n";
+ foreach my $thisone (sort {
+ # Deal with the case of an item actually being an array ref to 1 or 2
+ # hashrefs. Don't assign to $a or $b, as they're aliases to the orignal
+ my $l = ref $a eq 'ARRAY' ? ($a->[0] || $->[1]) : $a;
+ my $r = ref $b eq 'ARRAY' ? ($b->[0] || $->[1]) : $b;
+ # Sort by weight first
+ ($r->{weight} || 0) <=> ($l->{weight} || 0)
+ # Sort equal weights by name
+ or $l->{name} cmp $r->{name}}
+ # If this looks evil, maybe it is. $items is a
+ # hashref, and we're doing a hash slice on it
+ @{$items}{@{$best->{$char}}}) {
+ # warn "You are here";
+ if ($do_front_chop) {
+ $body .= $self->match_clause ({indent => 2 + length $indent,
+ checked_at => \$char}, $thisone);
+ } else {
+ $body .= $self->match_clause ({indent => 2 + length $indent,
+ checked_at => $offset}, $thisone);
+ }
+ }
+ $body .= $indent . " break;\n";
+ }
+ $body .= $indent . "}\n";
+ return $body;
+}
+
+sub C_constant_return_type {
+ "static int";
+}
+
+sub C_constant_prefix_param {
+ '';
+}
+
+sub C_constant_prefix_param_defintion {
+ '';
+}
+
+sub name_param_definition {
+ "const char *" . $_[0]->name_param;
+}
+
+sub namelen_param {
+ 'len';
+}
+
+sub namelen_param_definition {
+ 'size_t ' . $_[0]->namelen_param;
+}
+
+sub C_constant_other_params {
+ '';
+}
+
+sub C_constant_other_params_defintion {
+ '';
+}
+
+=item params WHAT
+
+An "internal" method, subject to change, currently called to allow an
+overriding class to cache information that will then be passed into all
+the C<*param*> calls. (Yes, having to read the source to make sense of this is
+considered a known bug). I<WHAT> is be a hashref of types the constant
+function will return. In ExtUtils::Constant::XS this method is used to
+returns a hashref keyed IV NV PV SV to show which combination of pointers will
+be needed in the C argument list generated by
+C_constant_other_params_definition and C_constant_other_params
+
+=cut
+
+sub params {
+ '';
+}
+
+
+=item dogfood arg_hashref, ITEM...
+
+An internal function to generate the embedded perl code that will regenerate
+the constant subroutines. Parameters are the same as for C_constant.
+
+Currently the base class does nothing and returns an empty string.
+
+=cut
+
+sub dogfood {
+ ''
+}
+
+=item normalise_items args, default_type, seen_types, seen_items, ITEM...
+
+Convert the items to a normalised form. For 8 bit and Unicode values converts
+the item to an array of 1 or 2 items, both 8 bit and UTF-8 encoded.
+
+=cut
+
+sub normalise_items
+{
+ my $self = shift;
+ my $args = shift;
+ my $default_type = shift;
+ my $what = shift;
+ my $items = shift;
+ my @new_items;
+ foreach my $orig (@_) {
+ my ($name, $item);
+ if (ref $orig) {
+ # Make a copy which is a normalised version of the ref passed in.
+ $name = $orig->{name};
+ my ($type, $macro, $value) = @$orig{qw (type macro value)};
+ $type ||= $default_type;
+ $what->{$type} = 1;
+ $item = {name=>$name, type=>$type};
+
+ undef $macro if defined $macro and $macro eq $name;
+ $item->{macro} = $macro if defined $macro;
+ undef $value if defined $value and $value eq $name;
+ $item->{value} = $value if defined $value;
+ foreach my $key (qw(default pre post def_pre def_post weight
+ not_constant)) {
+ my $value = $orig->{$key};
+ $item->{$key} = $value if defined $value;
+ # warn "$key $value";
+ }
+ } else {
+ $name = $orig;
+ $item = {name=>$name, type=>$default_type};
+ $what->{$default_type} = 1;
+ }
+ warn +(ref ($self) || $self)
+ . "doesn't know how to handle values of type $_ used in macro $name"
+ unless $self->valid_type ($item->{type});
+ # tr///c is broken on 5.6.1 for utf8, so my original tr/\0-\177//c
+ # doesn't work. Upgrade to 5.8
+ # if ($name !~ tr/\0-\177//c || $] < 5.005_50) {
+ if ($name =~ tr/\0-\177// == length $name || $] < 5.005_50
+ || $args->{disable_utf8_duplication}) {
+ # No characters outside 7 bit ASCII.
+ if (exists $items->{$name}) {
+ die "Multiple definitions for macro $name";
+ }
+ $items->{$name} = $item;
+ } else {
+ # No characters outside 8 bit. This is hardest.
+ if (exists $items->{$name} and ref $items->{$name} ne 'ARRAY') {
+ confess "Unexpected ASCII definition for macro $name";
+ }
+ # Again, 5.6.1 tr broken, so s/5\.6.*/5\.8\.0/;
+ # if ($name !~ tr/\0-\377//c) {
+ if ($name =~ tr/\0-\377// == length $name) {
+# if ($] < 5.007) {
+# $name = pack "C*", unpack "U*", $name;
+# }
+ $item->{utf8} = 'no';
+ $items->{$name}[1] = $item;
+ push @new_items, $item;
+ # Copy item, to create the utf8 variant.
+ $item = {%$item};
+ }
+ # Encode the name as utf8 bytes.
+ unless (is_perl56) {
+ utf8::encode($name);
+ } else {
+# warn "Was >$name< " . length ${name};
+ $name = pack 'C*', unpack 'C*', $name . pack 'U*';
+# warn "Now '${name}' " . length ${name};
+ }
+ if ($items->{$name}[0]) {
+ die "Multiple definitions for macro $name";
+ }
+ $item->{utf8} = 'yes';
+ $item->{name} = $name;
+ $items->{$name}[0] = $item;
+ # We have need for the utf8 flag.
+ $what->{''} = 1;
+ }
+ push @new_items, $item;
+ }
+ @new_items;
+}
+
+=item C_constant arg_hashref, ITEM...
+
+A function that returns a B<list> of C subroutine definitions that return
+the value and type of constants when passed the name by the XS wrapper.
+I<ITEM...> gives a list of constant names. Each can either be a string,
+which is taken as a C macro name, or a reference to a hash with the following
+keys
+
+=over 8
+
+=item name
+
+The name of the constant, as seen by the perl code.
+
+=item type
+
+The type of the constant (I<IV>, I<NV> etc)
+
+=item value
+
+A C expression for the value of the constant, or a list of C expressions if
+the type is aggregate. This defaults to the I<name> if not given.
+
+=item macro
+
+The C pre-processor macro to use in the C<#ifdef>. This defaults to the
+I<name>, and is mainly used if I<value> is an C<enum>. If a reference an
+array is passed then the first element is used in place of the C<#ifdef>
+line, and the second element in place of the C<#endif>. This allows
+pre-processor constructions such as
+
+ #if defined (foo)
+ #if !defined (bar)
+ ...
+ #endif
+ #endif
+
+to be used to determine if a constant is to be defined.
+
+A "macro" 1 signals that the constant is always defined, so the C<#if>/C<#endif>
+test is omitted.
+
+=item default
+
+Default value to use (instead of C<croak>ing with "your vendor has not
+defined...") to return if the macro isn't defined. Specify a reference to
+an array with type followed by value(s).
+
+=item pre
+
+C code to use before the assignment of the value of the constant. This allows
+you to use temporary variables to extract a value from part of a C<struct>
+and return this as I<value>. This C code is places at the start of a block,
+so you can declare variables in it.
+
+=item post
+
+C code to place between the assignment of value (to a temporary) and the
+return from the function. This allows you to clear up anything in I<pre>.
+Rarely needed.
+
+=item def_pre
+
+=item def_post
+
+Equivalents of I<pre> and I<post> for the default value.
+
+=item utf8
+
+Generated internally. Is zero or undefined if name is 7 bit ASCII,
+"no" if the name is 8 bit (and so should only match if SvUTF8() is false),
+"yes" if the name is utf8 encoded.
+
+The internals automatically clone any name with characters 128-255 but none
+256+ (ie one that could be either in bytes or utf8) into a second entry
+which is utf8 encoded.
+
+=item weight
+
+Optional sorting weight for names, to determine the order of
+linear testing when multiple names fall in the same case of a switch clause.
+Higher comes earlier, undefined defaults to zero.
+
+=back
+
+In the argument hashref, I<package> is the name of the package, and is only
+used in comments inside the generated C code. I<subname> defaults to
+C<constant> if undefined.
+
+I<default_type> is the type returned by C<ITEM>s that don't specify their
+type. It defaults to the value of C<default_type()>. I<types> should be given
+either as a comma separated list of types that the C subroutine I<subname>
+will generate or as a reference to a hash. I<default_type> will be added to
+the list if not present, as will any types given in the list of I<ITEM>s. The
+resultant list should be the same list of types that C<XS_constant> is
+given. [Otherwise C<XS_constant> and C<C_constant> may differ in the number of
+parameters to the constant function. I<indent> is currently unused and
+ignored. In future it may be used to pass in information used to change the C
+indentation style used.] The best way to maintain consistency is to pass in a
+hash reference and let this function update it.
+
+I<breakout> governs when child functions of I<subname> are generated. If there
+are I<breakout> or more I<ITEM>s with the same length of name, then the code
+to switch between them is placed into a function named I<subname>_I<len>, for
+example C<constant_5> for names 5 characters long. The default I<breakout> is
+3. A single C<ITEM> is always inlined.
+
+=cut
+
+# The parameter now BREAKOUT was previously documented as:
+#
+# I<NAMELEN> if defined signals that all the I<name>s of the I<ITEM>s are of
+# this length, and that the constant name passed in by perl is checked and
+# also of this length. It is used during recursion, and should be C<undef>
+# unless the caller has checked all the lengths during code generation, and
+# the generated subroutine is only to be called with a name of this length.
+#
+# As you can see it now performs this function during recursion by being a
+# scalar reference.
+
+sub C_constant {
+ my ($self, $args, @items) = @_;
+ my ($package, $subname, $default_type, $what, $indent, $breakout) =
+ @{$args}{qw(package subname default_type types indent breakout)};
+ $package ||= 'Foo';
+ $subname ||= 'constant';
+ # I'm not using this. But a hashref could be used for full formatting without
+ # breaking this API
+ # $indent ||= 0;
+
+ my ($namelen, $items);
+ if (ref $breakout) {
+ # We are called recursively. We trust @items to be normalised, $what to
+ # be a hashref, and pinch %$items from our parent to save recalculation.
+ ($namelen, $items) = @$breakout;
+ } else {
+ $items = {};
+ if (is_perl56) {
+ # Need proper Unicode preserving hash keys.
+ require ExtUtils::Constant::Aaargh56Hash;
+ tie %$items, 'ExtUtils::Constant::Aaargh56Hash';
+ }
+ $breakout ||= 3;
+ $default_type ||= $self->default_type();
+ if (!ref $what) {
+ # Convert line of the form IV,UV,NV to hash
+ $what = {map {$_ => 1} split /,\s*/, ($what || '')};
+ # Figure out what types we're dealing with, and assign all unknowns to the
+ # default type
+ }
+ @items = $self->normalise_items ({}, $default_type, $what, $items, @items);
+ # use Data::Dumper; print Dumper @items;
+ }
+ my $params = $self->params ($what);
+
+ # Probably "static int"
+ my ($body, @subs);
+ $body = $self->C_constant_return_type($params) . "\n$subname ("
+ # Eg "pTHX_ "
+ . $self->C_constant_prefix_param_defintion($params)
+ # Probably "const char *name"
+ . $self->name_param_definition($params);
+ # Something like ", STRLEN len"
+ $body .= ", " . $self->namelen_param_definition($params)
+ unless defined $namelen;
+ $body .= $self->C_constant_other_params_defintion($params);
+ $body .= ") {\n";
+
+ if (defined $namelen) {
+ # We are a child subroutine. Print the simple description
+ my $comment = 'When generated this function returned values for the list'
+ . ' of names given here. However, subsequent manual editing may have'
+ . ' added or removed some.';
+ $body .= $self->switch_clause ({indent=>2, comment=>$comment},
+ $namelen, $items, @items);
+ } else {
+ # We are the top level.
+ $body .= " /* Initially switch on the length of the name. */\n";
+ $body .= $self->dogfood ({package => $package, subname => $subname,
+ default_type => $default_type, what => $what,
+ indent => $indent, breakout => $breakout},
+ @items);
+ $body .= ' switch ('.$self->namelen_param().") {\n";
+ # Need to group names of the same length
+ my @by_length;
+ foreach (@items) {
+ push @{$by_length[length $_->{name}]}, $_;
+ }
+ foreach my $i (0 .. $#by_length) {
+ next unless $by_length[$i]; # None of this length
+ $body .= " case $i:\n";
+ if (@{$by_length[$i]} == 1) {
+ my $only_thing = $by_length[$i]->[0];
+ if ($only_thing->{utf8}) {
+ if ($only_thing->{utf8} eq 'yes') {
+ # With utf8 on flag item is passed in element 0
+ $body .= $self->match_clause (undef, [$only_thing]);
+ } else {
+ # With utf8 off flag item is passed in element 1
+ $body .= $self->match_clause (undef, [undef, $only_thing]);
+ }
+ } else {
+ $body .= $self->match_clause (undef, $only_thing);
+ }
+ } elsif (@{$by_length[$i]} < $breakout) {
+ $body .= $self->switch_clause ({indent=>4},
+ $i, $items, @{$by_length[$i]});
+ } else {
+ # Only use the minimal set of parameters actually needed by the types
+ # of the names of this length.
+ my $what = {};
+ foreach (@{$by_length[$i]}) {
+ $what->{$_->{type}} = 1;
+ $what->{''} = 1 if $_->{utf8};
+ }
+ $params = $self->params ($what);
+ push @subs, $self->C_constant ({package=>$package,
+ subname=>"${subname}_$i",
+ default_type => $default_type,
+ types => $what, indent => $indent,
+ breakout => [$i, $items]},
+ @{$by_length[$i]});
+ $body .= " return ${subname}_$i ("
+ # Eg "aTHX_ "
+ . $self->C_constant_prefix_param($params)
+ # Probably "name"
+ . $self->name_param($params);
+ $body .= $self->C_constant_other_params($params);
+ $body .= ");\n";
+ }
+ $body .= " break;\n";
+ }
+ $body .= " }\n";
+ }
+ my $notfound = $self->return_statement_for_notfound();
+ $body .= " $notfound\n" if $notfound;
+ $body .= "}\n";
+ return (@subs, $body);
+}
+
+1;
+__END__
+
+=back
+
+=head1 BUGS
+
+Not everything is documented yet.
+
+Probably others.
+
+=head1 AUTHOR
+
+Nicholas Clark <nick@ccl4.org> based on the code in C<h2xs> by Larry Wall and
+others