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# Disassembler.pm
#
# Copyright (c) 1996 Malcolm Beattie
#
# You may distribute under the terms of either the GNU General Public
# License or the Artistic License, as specified in the README file.
package B::Disassembler::BytecodeStream;
use FileHandle;
use Carp;
use B qw(cstring cast_I32);
@ISA = qw(FileHandle);
sub readn {
my ($fh, $len) = @_;
my $data;
read($fh, $data, $len);
croak "reached EOF while reading $len bytes" unless length($data) == $len;
return $data;
}
sub GET_U8 {
my $fh = shift;
my $c = $fh->getc;
croak "reached EOF while reading U8" unless defined($c);
return ord($c);
}
sub GET_U16 {
my $fh = shift;
my $str = $fh->readn(2);
croak "reached EOF while reading U16" unless length($str) == 2;
return unpack("n", $str);
}
sub GET_NV {
my $fh = shift;
my $str = $fh->readn(8);
croak "reached EOF while reading NV" unless length($str) == 8;
return unpack("N", $str);
}
sub GET_U32 {
my $fh = shift;
my $str = $fh->readn(4);
croak "reached EOF while reading U32" unless length($str) == 4;
return unpack("N", $str);
}
sub GET_I32 {
my $fh = shift;
my $str = $fh->readn(4);
croak "reached EOF while reading I32" unless length($str) == 4;
return cast_I32(unpack("N", $str));
}
sub GET_objindex {
my $fh = shift;
my $str = $fh->readn(4);
croak "reached EOF while reading objindex" unless length($str) == 4;
return unpack("N", $str);
}
sub GET_opindex {
my $fh = shift;
my $str = $fh->readn(4);
croak "reached EOF while reading opindex" unless length($str) == 4;
return unpack("N", $str);
}
sub GET_svindex {
my $fh = shift;
my $str = $fh->readn(4);
croak "reached EOF while reading svindex" unless length($str) == 4;
return unpack("N", $str);
}
sub GET_strconst {
my $fh = shift;
my ($str, $c);
while (defined($c = $fh->getc) && $c ne "\0") {
$str .= $c;
}
croak "reached EOF while reading strconst" unless defined($c);
return cstring($str);
}
sub GET_pvcontents {}
sub GET_PV {
my $fh = shift;
my $str;
my $len = $fh->GET_U32;
if ($len) {
read($fh, $str, $len);
croak "reached EOF while reading PV" unless length($str) == $len;
return cstring($str);
} else {
return '""';
}
}
sub GET_comment_t {
my $fh = shift;
my ($str, $c);
while (defined($c = $fh->getc) && $c ne "\n") {
$str .= $c;
}
croak "reached EOF while reading comment" unless defined($c);
return cstring($str);
}
sub GET_double {
my $fh = shift;
my ($str, $c);
while (defined($c = $fh->getc) && $c ne "\0") {
$str .= $c;
}
croak "reached EOF while reading double" unless defined($c);
return $str;
}
sub GET_none {}
sub GET_op_tr_array {
my $fh = shift;
my @ary = unpack("n256", $fh->readn(256 * 2));
return join(",", @ary);
}
sub GET_IV64 {
my $fh = shift;
my ($hi, $lo) = unpack("NN", $fh->readn(8));
return sprintf("0x%4x%04x", $hi, $lo); # cheat
}
package B::Disassembler;
use Exporter;
@ISA = qw(Exporter);
@EXPORT_OK = qw(disassemble_fh);
use Carp;
use strict;
use B::Asmdata qw(%insn_data @insn_name);
sub disassemble_fh {
my ($fh, $out) = @_;
my ($c, $getmeth, $insn, $arg);
bless $fh, "B::Disassembler::BytecodeStream";
while (defined($c = $fh->getc)) {
$c = ord($c);
$insn = $insn_name[$c];
if (!defined($insn) || $insn eq "unused") {
my $pos = $fh->tell - 1;
die "Illegal instruction code $c at stream offset $pos\n";
}
$getmeth = $insn_data{$insn}->[2];
$arg = $fh->$getmeth();
if (defined($arg)) {
&$out($insn, $arg);
} else {
&$out($insn);
}
}
}
1;
__END__
=head1 NAME
B::Disassembler - Disassemble Perl bytecode
=head1 SYNOPSIS
use Disassembler;
=head1 DESCRIPTION
See F<ext/B/B/Disassembler.pm>.
=head1 AUTHOR
Malcolm Beattie, C<mbeattie@sable.ox.ac.uk>
=cut
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