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lib/Archive/Zip/ZipFileMember.pm  view on Meta::CPAN

    $where = $self->localHeaderRelativeOffset() unless defined($where);

    # avoid loop on certain corrupt files (from Julian Field)
    return _formatError("corrupt zip file")
      if defined($previousWhere) && $where == $previousWhere;

    my $status;
    my $signature;

    $status = $self->fh()->seek($where, IO::Seekable::SEEK_SET);
    return _ioError("seeking to local header") unless $status;

    ($status, $signature) =
      _readSignature($self->fh(), $self->externalFileName(),
                     LOCAL_FILE_HEADER_SIGNATURE, 1);
    return $status if $status == AZ_IO_ERROR;

    # retry with EOCD offset if any was given.
    if ($status == AZ_FORMAT_ERROR && $self->{'possibleEocdOffset'}) {
        $status = $self->_seekToLocalHeader(
            $self->localHeaderRelativeOffset() + $self->{'possibleEocdOffset'},
            $where
        );
        if ($status == AZ_OK) {
            $self->{'localHeaderRelativeOffset'} +=
              $self->{'possibleEocdOffset'};
            $self->{'possibleEocdOffset'} = 0;
        }
    }

    return $status;
}

# Because I'm going to delete the file handle, read the local file
# header if the file handle is seekable. If it is not, I assume that
# I've already read the local header.
# Return ( $status, $self )

sub _become {
    my $self     = shift;
    my $newClass = shift;
    return $self if ref($self) eq $newClass;

    my $status = AZ_OK;

    if (_isSeekable($self->fh())) {
        my $here = $self->fh()->tell();
        $status = $self->_seekToLocalHeader();
        $status = $self->_readLocalFileHeader() if $status == AZ_OK;
        $self->fh()->seek($here, IO::Seekable::SEEK_SET);
        return $status unless $status == AZ_OK;
    }

    delete($self->{'eocdCrc32'});
    delete($self->{'diskNumberStart'});
    delete($self->{'localHeaderRelativeOffset'});
    delete($self->{'dataOffset'});
    delete($self->{'archiveZip64'});
    delete($self->{'possibleEocdOffset'});

    return $self->SUPER::_become($newClass);
}

sub diskNumberStart {
    shift->{'diskNumberStart'};
}

sub localHeaderRelativeOffset {
    shift->{'localHeaderRelativeOffset'};
}

sub dataOffset {
    shift->{'dataOffset'};
}

# Skip local file header, updating only extra field stuff.
# Assumes that fh is positioned before signature.
sub _skipLocalFileHeader {
    my $self = shift;
    my $header;
    my $bytesRead = $self->fh()->read($header, LOCAL_FILE_HEADER_LENGTH);
    if ($bytesRead != LOCAL_FILE_HEADER_LENGTH) {
        return _ioError("reading local file header");
    }
    my $fileNameLength;
    my $extraFieldLength;
    my $bitFlag;
    (
        undef,    # $self->{'versionNeededToExtract'},
        $bitFlag,
        undef,    # $self->{'compressionMethod'},
        undef,    # $self->{'lastModFileDateTime'},
        undef,    # $crc32,
        undef,    # $compressedSize,
        undef,    # $uncompressedSize,
        $fileNameLength,
        $extraFieldLength
    ) = unpack(LOCAL_FILE_HEADER_FORMAT, $header);

    if ($fileNameLength) {
        $self->fh()->seek($fileNameLength, IO::Seekable::SEEK_CUR)
          or return _ioError("skipping local file name");
    }

    my $zip64 = 0;
    if ($extraFieldLength) {
        $bytesRead =
          $self->fh()->read($self->{'localExtraField'}, $extraFieldLength);
        if ($bytesRead != $extraFieldLength) {
            return _ioError("reading local extra field");
        }
        if ($self->{'archiveZip64'}) {
            my $status;
            ($status, $zip64) =
              $self->_extractZip64ExtraField($self->{'localExtraField'}, undef, undef);
            return $status if $status != AZ_OK;
            $self->{'zip64'} ||= $zip64;
        }
    }

    $self->{'dataOffset'} = $self->fh()->tell();

lib/Archive/Zip/ZipFileMember.pm  view on Meta::CPAN

        $self->{'bitFlag'},
        $self->{'compressionMethod'},
        $self->{'lastModFileDateTime'},
        $self->{'crc32'},
        $self->{'compressedSize'},
        $self->{'uncompressedSize'},
        $fileNameLength,
        $extraFieldLength,
        $fileCommentLength,
        $self->{'diskNumberStart'},
        $self->{'internalFileAttributes'},
        $self->{'externalFileAttributes'},
        $self->{'localHeaderRelativeOffset'}
    ) = unpack(CENTRAL_DIRECTORY_FILE_HEADER_FORMAT, $header);

    $self->{'eocdCrc32'} = $self->{'crc32'};

    if ($fileNameLength) {
        $bytesRead = $fh->read($self->{'fileName'}, $fileNameLength);
        if ($bytesRead != $fileNameLength) {
            _ioError("reading central dir filename");
        }
    }
    if ($extraFieldLength) {
        $bytesRead = $fh->read($self->{'cdExtraField'}, $extraFieldLength);
        if ($bytesRead != $extraFieldLength) {
            return _ioError("reading central dir extra field");
        }
        if ($self->{'archiveZip64'}) {
            my ($status, $zip64) =
              $self->_extractZip64ExtraField($self->{'cdExtraField'},
                                             $self->{'uncompressedSize'},
                                             $self->{'compressedSize'},
                                             $self->{'localHeaderRelativeOffset'},
                                             $self->{'diskNumberStart'});
            return $status if $status != AZ_OK;
            $self->{'zip64'} ||= $zip64;
        }
    }
    if ($fileCommentLength) {
        $bytesRead = $fh->read($self->{'fileComment'}, $fileCommentLength);
        if ($bytesRead != $fileCommentLength) {
            return _ioError("reading central dir file comment");
        }
    }

    # NK 10/21/04: added to avoid problems with manipulated headers
    if (    $self->{'uncompressedSize'} != $self->{'compressedSize'}
        and $self->{'compressionMethod'} == COMPRESSION_STORED) {
        $self->{'uncompressedSize'} = $self->{'compressedSize'};
    }

    $self->desiredCompressionMethod($self->compressionMethod());

    return AZ_OK;
}

sub rewindData {
    my $self = shift;

    my $status = $self->SUPER::rewindData(@_);
    return $status unless $status == AZ_OK;

    return AZ_IO_ERROR unless $self->fh();

    $self->fh()->clearerr();

    # Seek to local file header.
    # The only reason that I'm doing this this way is that the extraField
    # length seems to be different between the CD header and the LF header.
    $status = $self->_seekToLocalHeader();
    return $status unless $status == AZ_OK;

    # skip local file header
    $status = $self->_skipLocalFileHeader();
    return $status unless $status == AZ_OK;

    # Seek to beginning of file data
    $self->fh()->seek($self->dataOffset(), IO::Seekable::SEEK_SET)
      or return _ioError("seeking to beginning of file data");

    return AZ_OK;
}

# Return bytes read. Note that first parameter is a ref to a buffer.
# my $data;
# my ( $bytesRead, $status) = $self->readRawChunk( \$data, $chunkSize );
sub _readRawChunk {
    my ($self, $dataRef, $chunkSize) = @_;
    return (0, AZ_OK) unless $chunkSize;
    my $bytesRead = $self->fh()->read($$dataRef, $chunkSize)
      or return (0, _ioError("reading data"));
    return ($bytesRead, AZ_OK);
}

1;