diff options
Diffstat (limited to 'gcc-4.8.1/libgo/go/archive/tar/reader.go')
| -rw-r--r-- | gcc-4.8.1/libgo/go/archive/tar/reader.go | 235 |
1 files changed, 0 insertions, 235 deletions
diff --git a/gcc-4.8.1/libgo/go/archive/tar/reader.go b/gcc-4.8.1/libgo/go/archive/tar/reader.go deleted file mode 100644 index ad825c6be..000000000 --- a/gcc-4.8.1/libgo/go/archive/tar/reader.go +++ /dev/null @@ -1,235 +0,0 @@ -// 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 - -// TODO(dsymonds): -// - pax extensions - -import ( - "bytes" - "errors" - "io" - "io/ioutil" - "os" - "strconv" - "time" -) - -var ( - ErrHeader = errors.New("archive/tar: invalid tar header") -) - -// A Reader provides sequential access to the contents of a tar archive. -// A tar archive consists of a sequence of files. -// The Next method advances to the next file in the archive (including the first), -// and then it can be treated as an io.Reader to access the file's data. -// -// Example: -// tr := tar.NewReader(r) -// for { -// hdr, err := tr.Next() -// if err == io.EOF { -// // end of tar archive -// break -// } -// if err != nil { -// // handle error -// } -// io.Copy(data, tr) -// } -type Reader struct { - r io.Reader - err error - nb int64 // number of unread bytes for current file entry - pad int64 // amount of padding (ignored) after current file entry -} - -// NewReader creates a new Reader reading from r. -func NewReader(r io.Reader) *Reader { return &Reader{r: r} } - -// Next advances to the next entry in the tar archive. -func (tr *Reader) Next() (*Header, error) { - var hdr *Header - if tr.err == nil { - tr.skipUnread() - } - if tr.err == nil { - hdr = tr.readHeader() - } - return hdr, tr.err -} - -// Parse bytes as a NUL-terminated C-style string. -// If a NUL byte is not found then the whole slice is returned as a string. -func cString(b []byte) string { - n := 0 - for n < len(b) && b[n] != 0 { - n++ - } - return string(b[0:n]) -} - -func (tr *Reader) octal(b []byte) int64 { - // Check for binary format first. - if len(b) > 0 && b[0]&0x80 != 0 { - var x int64 - for i, c := range b { - if i == 0 { - c &= 0x7f // ignore signal bit in first byte - } - x = x<<8 | int64(c) - } - return x - } - - // Removing leading spaces. - for len(b) > 0 && b[0] == ' ' { - b = b[1:] - } - // Removing trailing NULs and spaces. - for len(b) > 0 && (b[len(b)-1] == ' ' || b[len(b)-1] == '\x00') { - b = b[0 : len(b)-1] - } - x, err := strconv.ParseUint(cString(b), 8, 64) - if err != nil { - tr.err = err - } - return int64(x) -} - -// Skip any unread bytes in the existing file entry, as well as any alignment padding. -func (tr *Reader) skipUnread() { - nr := tr.nb + tr.pad // number of bytes to skip - tr.nb, tr.pad = 0, 0 - if sr, ok := tr.r.(io.Seeker); ok { - if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil { - return - } - } - _, tr.err = io.CopyN(ioutil.Discard, tr.r, nr) -} - -func (tr *Reader) verifyChecksum(header []byte) bool { - if tr.err != nil { - return false - } - - given := tr.octal(header[148:156]) - unsigned, signed := checksum(header) - return given == unsigned || given == signed -} - -func (tr *Reader) readHeader() *Header { - header := make([]byte, blockSize) - if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil { - return nil - } - - // Two blocks of zero bytes marks the end of the archive. - if bytes.Equal(header, zeroBlock[0:blockSize]) { - if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil { - return nil - } - if bytes.Equal(header, zeroBlock[0:blockSize]) { - tr.err = io.EOF - } else { - tr.err = ErrHeader // zero block and then non-zero block - } - return nil - } - - if !tr.verifyChecksum(header) { - tr.err = ErrHeader - return nil - } - - // Unpack - hdr := new(Header) - s := slicer(header) - - hdr.Name = cString(s.next(100)) - hdr.Mode = tr.octal(s.next(8)) - hdr.Uid = int(tr.octal(s.next(8))) - hdr.Gid = int(tr.octal(s.next(8))) - hdr.Size = tr.octal(s.next(12)) - hdr.ModTime = time.Unix(tr.octal(s.next(12)), 0) - s.next(8) // chksum - hdr.Typeflag = s.next(1)[0] - hdr.Linkname = cString(s.next(100)) - - // The remainder of the header depends on the value of magic. - // The original (v7) version of tar had no explicit magic field, - // so its magic bytes, like the rest of the block, are NULs. - magic := string(s.next(8)) // contains version field as well. - var format string - switch magic { - case "ustar\x0000": // POSIX tar (1003.1-1988) - if string(header[508:512]) == "tar\x00" { - format = "star" - } else { - format = "posix" - } - case "ustar \x00": // old GNU tar - format = "gnu" - } - - switch format { - case "posix", "gnu", "star": - hdr.Uname = cString(s.next(32)) - hdr.Gname = cString(s.next(32)) - devmajor := s.next(8) - devminor := s.next(8) - if hdr.Typeflag == TypeChar || hdr.Typeflag == TypeBlock { - hdr.Devmajor = tr.octal(devmajor) - hdr.Devminor = tr.octal(devminor) - } - var prefix string - switch format { - case "posix", "gnu": - prefix = cString(s.next(155)) - case "star": - prefix = cString(s.next(131)) - hdr.AccessTime = time.Unix(tr.octal(s.next(12)), 0) - hdr.ChangeTime = time.Unix(tr.octal(s.next(12)), 0) - } - if len(prefix) > 0 { - hdr.Name = prefix + "/" + hdr.Name - } - } - - if tr.err != nil { - tr.err = ErrHeader - return nil - } - - // Maximum value of hdr.Size is 64 GB (12 octal digits), - // so there's no risk of int64 overflowing. - tr.nb = int64(hdr.Size) - tr.pad = -tr.nb & (blockSize - 1) // blockSize is a power of two - - return hdr -} - -// Read reads from the current entry in the tar archive. -// It returns 0, io.EOF when it reaches the end of that entry, -// until Next is called to advance to the next entry. -func (tr *Reader) Read(b []byte) (n int, err error) { - if tr.nb == 0 { - // file consumed - return 0, io.EOF - } - - if int64(len(b)) > tr.nb { - b = b[0:tr.nb] - } - n, err = tr.r.Read(b) - tr.nb -= int64(n) - - if err == io.EOF && tr.nb > 0 { - err = io.ErrUnexpectedEOF - } - tr.err = err - return -} |