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lib/ExtUtils/Constant.pm  view on Meta::CPAN

=cut

sub XS_constant {
  my $package = shift;
  my $what = shift;
  my $XS_subname = shift;
  my $C_subname = shift;
  $XS_subname ||= 'constant';
  $C_subname ||= $XS_subname;

  if (!ref $what) {
    # Convert line of the form IV,UV,NV to hash
    $what = {map {$_ => 1} split /,\s*/, ($what)};
  }
  my $params = ExtUtils::Constant::XS->params ($what);
  my $type;

  my $xs = <<"EOT";
void
$XS_subname(sv)
    PREINIT:
#ifdef dXSTARG
	dXSTARG; /* Faster if we have it.  */
#else
	dTARGET;
#endif
	STRLEN		len;
        int		type;
EOT

  if ($params->{IV}) {
    $xs .= "	IV		iv = 0; /* avoid uninit var warning */\n";
  } else {
    $xs .= "	/* IV\t\tiv;\tUncomment this if you need to return IVs */\n";
  }
  if ($params->{NV}) {
    $xs .= "	NV		nv = 0.0; /* avoid uninit var warning */\n";
  } else {
    $xs .= "	/* NV\t\tnv;\tUncomment this if you need to return NVs */\n";
  }
  if ($params->{PV}) {
    $xs .= "	const char	*pv = NULL; /* avoid uninit var warning */\n";
  } else {
    $xs .=
      "	/* const char\t*pv;\tUncomment this if you need to return PVs */\n";
  }

  $xs .= << 'EOT';
    INPUT:
	SV *		sv;
        const char *	s = SvPV(sv, len);
EOT
  if ($params->{''}) {
  $xs .= << 'EOT';
    INPUT:
	int		utf8 = SvUTF8(sv);
EOT
  }
  $xs .= << 'EOT';
    PPCODE:
EOT

  if ($params->{IV} xor $params->{NV}) {
    $xs .= << "EOT";
        /* Change this to $C_subname(aTHX_ s, len, &iv, &nv);
           if you need to return both NVs and IVs */
EOT
  }
  $xs .= "	type = $C_subname(aTHX_ s, len";
  $xs .= ', utf8' if $params->{''};
  $xs .= ', &iv' if $params->{IV};
  $xs .= ', &nv' if $params->{NV};
  $xs .= ', &pv' if $params->{PV};
  $xs .= ', &sv' if $params->{SV};
  $xs .= ");\n";

  # If anyone is insane enough to suggest a package name containing %
  my $package_sprintf_safe = $package;
  $package_sprintf_safe =~ s/%/%%/g;

  $xs .= << "EOT";
      /* Return 1 or 2 items. First is error message, or undef if no error.
           Second, if present, is found value */
        switch (type) {
        case PERL_constant_NOTFOUND:
          sv =
	    sv_2mortal(newSVpvf("%s is not a valid $package_sprintf_safe macro", s));
          PUSHs(sv);
          break;
        case PERL_constant_NOTDEF:
          sv = sv_2mortal(newSVpvf(
	    "Your vendor has not defined $package_sprintf_safe macro %s, used",
				   s));
          PUSHs(sv);
          break;
EOT

  foreach $type (sort keys %XS_Constant) {
    # '' marks utf8 flag needed.
    next if $type eq '';
    $xs .= "\t/* Uncomment this if you need to return ${type}s\n"
      unless $what->{$type};
    $xs .= "        case PERL_constant_IS$type:\n";
    if (length $XS_Constant{$type}) {
      $xs .= << "EOT";
          EXTEND(SP, 2);
          PUSHs(&PL_sv_undef);
          $XS_Constant{$type};
EOT
    } else {
      # Do nothing. return (), which will be correctly interpreted as
      # (undef, undef)
    }
    $xs .= "          break;\n";
    unless ($what->{$type}) {
      chop $xs; # Yes, another need for chop not chomp.
      $xs .= " */\n";
    }
  }
  $xs .= << "EOT";