From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libgo/go/archive/tar/writer.go | 205 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) create mode 100644 libgo/go/archive/tar/writer.go (limited to 'libgo/go/archive/tar/writer.go') diff --git a/libgo/go/archive/tar/writer.go b/libgo/go/archive/tar/writer.go new file mode 100644 index 000000000..8673bad31 --- /dev/null +++ b/libgo/go/archive/tar/writer.go @@ -0,0 +1,205 @@ +// 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): +// - catch more errors (no first header, write after close, etc.) + +import ( + "io" + "os" + "strconv" +) + +var ( + ErrWriteTooLong = os.NewError("write too long") + ErrFieldTooLong = os.NewError("header field too long") + ErrWriteAfterClose = os.NewError("write after close") +) + +// A Writer provides sequential writing of a tar archive in POSIX.1 format. +// A tar archive consists of a sequence of files. +// Call WriteHeader to begin a new file, and then call Write to supply that file's data, +// writing at most hdr.Size bytes in total. +// +// Example: +// tw := tar.NewWriter(w) +// hdr := new(Header) +// hdr.Size = length of data in bytes +// // populate other hdr fields as desired +// if err := tw.WriteHeader(hdr); err != nil { +// // handle error +// } +// io.Copy(tw, data) +// tw.Close() +type Writer struct { + w io.Writer + err os.Error + nb int64 // number of unwritten bytes for current file entry + pad int64 // amount of padding to write after current file entry + closed bool + usedBinary bool // whether the binary numeric field extension was used +} + +// NewWriter creates a new Writer writing to w. +func NewWriter(w io.Writer) *Writer { return &Writer{w: w} } + +// Flush finishes writing the current file (optional). +func (tw *Writer) Flush() os.Error { + n := tw.nb + tw.pad + for n > 0 && tw.err == nil { + nr := n + if nr > blockSize { + nr = blockSize + } + var nw int + nw, tw.err = tw.w.Write(zeroBlock[0:nr]) + n -= int64(nw) + } + tw.nb = 0 + tw.pad = 0 + return tw.err +} + +// Write s into b, terminating it with a NUL if there is room. +func (tw *Writer) cString(b []byte, s string) { + if len(s) > len(b) { + if tw.err == nil { + tw.err = ErrFieldTooLong + } + return + } + copy(b, s) + if len(s) < len(b) { + b[len(s)] = 0 + } +} + +// Encode x as an octal ASCII string and write it into b with leading zeros. +func (tw *Writer) octal(b []byte, x int64) { + s := strconv.Itob64(x, 8) + // leading zeros, but leave room for a NUL. + for len(s)+1 < len(b) { + s = "0" + s + } + tw.cString(b, s) +} + +// Write x into b, either as octal or as binary (GNUtar/star extension). +func (tw *Writer) numeric(b []byte, x int64) { + // Try octal first. + s := strconv.Itob64(x, 8) + if len(s) < len(b) { + tw.octal(b, x) + return + } + // Too big: use binary (big-endian). + tw.usedBinary = true + for i := len(b) - 1; x > 0 && i >= 0; i-- { + b[i] = byte(x) + x >>= 8 + } + b[0] |= 0x80 // highest bit indicates binary format +} + +// WriteHeader writes hdr and prepares to accept the file's contents. +// WriteHeader calls Flush if it is not the first header. +// Calling after a Close will return ErrWriteAfterClose. +func (tw *Writer) WriteHeader(hdr *Header) os.Error { + if tw.closed { + return ErrWriteAfterClose + } + if tw.err == nil { + tw.Flush() + } + if tw.err != nil { + return tw.err + } + + tw.nb = int64(hdr.Size) + tw.pad = -tw.nb & (blockSize - 1) // blockSize is a power of two + + header := make([]byte, blockSize) + s := slicer(header) + + // TODO(dsymonds): handle names longer than 100 chars + copy(s.next(100), []byte(hdr.Name)) + + tw.octal(s.next(8), hdr.Mode) // 100:108 + tw.numeric(s.next(8), int64(hdr.Uid)) // 108:116 + tw.numeric(s.next(8), int64(hdr.Gid)) // 116:124 + tw.numeric(s.next(12), hdr.Size) // 124:136 + tw.numeric(s.next(12), hdr.Mtime) // 136:148 + s.next(8) // chksum (148:156) + s.next(1)[0] = hdr.Typeflag // 156:157 + s.next(100) // linkname (157:257) + copy(s.next(8), []byte("ustar\x0000")) // 257:265 + tw.cString(s.next(32), hdr.Uname) // 265:297 + tw.cString(s.next(32), hdr.Gname) // 297:329 + tw.numeric(s.next(8), hdr.Devmajor) // 329:337 + tw.numeric(s.next(8), hdr.Devminor) // 337:345 + + // Use the GNU magic instead of POSIX magic if we used any GNU extensions. + if tw.usedBinary { + copy(header[257:265], []byte("ustar \x00")) + } + + // The chksum field is terminated by a NUL and a space. + // This is different from the other octal fields. + chksum, _ := checksum(header) + tw.octal(header[148:155], chksum) + header[155] = ' ' + + if tw.err != nil { + // problem with header; probably integer too big for a field. + return tw.err + } + + _, tw.err = tw.w.Write(header) + + return tw.err +} + +// Write writes to the current entry in the tar archive. +// Write returns the error ErrWriteTooLong if more than +// hdr.Size bytes are written after WriteHeader. +func (tw *Writer) Write(b []byte) (n int, err os.Error) { + if tw.closed { + err = ErrWriteTooLong + return + } + overwrite := false + if int64(len(b)) > tw.nb { + b = b[0:tw.nb] + overwrite = true + } + n, err = tw.w.Write(b) + tw.nb -= int64(n) + if err == nil && overwrite { + err = ErrWriteTooLong + return + } + tw.err = err + return +} + +// Close closes the tar archive, flushing any unwritten +// data to the underlying writer. +func (tw *Writer) Close() os.Error { + if tw.err != nil || tw.closed { + return tw.err + } + tw.Flush() + tw.closed = true + + // trailer: two zero blocks + for i := 0; i < 2; i++ { + _, tw.err = tw.w.Write(zeroBlock) + if tw.err != nil { + break + } + } + return tw.err +} -- cgit v1.2.3