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- package ExtUtils::Constant::Base;
-
- use strict;
- use vars qw($VERSION $is_perl56);
- use Carp;
- use Text::Wrap;
- use ExtUtils::Constant::Utils qw(C_stringify perl_stringify);
-
- $VERSION = '0.01';
-
- $is_perl56 = ($] < 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 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, $macro, $default, $pre, $post, $def_pre, $def_post, $type)
- = @$item{qw (name value macro default pre post def_pre def_post type)};
- $value = $name unless defined $value;
- $macro = $self->macro_from_name($item) unless defined $macro;
- # "#if 1" is true to a C pre-processor
- $macro = 1 if !defined $macro or $macro eq '';
- $indent = ' ' x ($indent || 6);
- unless (defined $type) {
- # use Data::Dumper; print STDERR Dumper ($item);
- confess "undef \$type";
- }
-
- my $clause;
-
- ##ifdef thingy
- if (ref $macro) {
- $clause = $macro->[0];
- } elsif ($macro ne "1") {
- $clause = "#ifdef $macro\n";
- }
-
- # *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 (ref $macro or $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
- if (ref $macro) {
- $clause .= $macro->[1];
- } else {
- $clause .= "#endif\n";
- }
- }
- 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 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 {
- if ($is_perl56) {
- # Need proper Unicode preserving hash keys.
- require ExtUtils::Constant::Aaargh56Hash;
- $items = {};
- tie %$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
- }
- my @new_items;
- foreach my $orig (@items) {
- my ($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)) {
- 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) {
- # 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;
- }
- @items = @new_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
-