| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package tar implements access to tar archives. |
| // It aims to cover most of the variations, including those produced |
| // by GNU and BSD tars. |
| // |
| // References: |
| // http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5 |
| // http://www.gnu.org/software/tar/manual/html_node/Standard.html |
| package tar |
| |
| import "time" |
| |
| const ( |
| blockSize = 512 |
| |
| // Types |
| TypeReg = '0' // regular file |
| TypeRegA = '\x00' // regular file |
| TypeLink = '1' // hard link |
| TypeSymlink = '2' // symbolic link |
| TypeChar = '3' // character device node |
| TypeBlock = '4' // block device node |
| TypeDir = '5' // directory |
| TypeFifo = '6' // fifo node |
| TypeCont = '7' // reserved |
| TypeXHeader = 'x' // extended header |
| TypeXGlobalHeader = 'g' // global extended header |
| ) |
| |
| // A Header represents a single header in a tar archive. |
| // Some fields may not be populated. |
| type Header struct { |
| Name string // name of header file entry |
| Mode int64 // permission and mode bits |
| Uid int // user id of owner |
| Gid int // group id of owner |
| Size int64 // length in bytes |
| ModTime time.Time // modified time |
| Typeflag byte // type of header entry |
| Linkname string // target name of link |
| Uname string // user name of owner |
| Gname string // group name of owner |
| Devmajor int64 // major number of character or block device |
| Devminor int64 // minor number of character or block device |
| AccessTime time.Time // access time |
| ChangeTime time.Time // status change time |
| } |
| |
| var zeroBlock = make([]byte, blockSize) |
| |
| // POSIX specifies a sum of the unsigned byte values, but the Sun tar uses signed byte values. |
| // We compute and return both. |
| func checksum(header []byte) (unsigned int64, signed int64) { |
| for i := 0; i < len(header); i++ { |
| if i == 148 { |
| // The chksum field (header[148:156]) is special: it should be treated as space bytes. |
| unsigned += ' ' * 8 |
| signed += ' ' * 8 |
| i += 7 |
| continue |
| } |
| unsigned += int64(header[i]) |
| signed += int64(int8(header[i])) |
| } |
| return |
| } |
| |
| type slicer []byte |
| |
| func (sp *slicer) next(n int) (b []byte) { |
| s := *sp |
| b, *sp = s[0:n], s[n:] |
| return |
| } |