diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/gzip/gunzip.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/gzip/gunzip.go | 344 |
1 files changed, 0 insertions, 344 deletions
diff --git a/vendor/github.com/klauspost/compress/gzip/gunzip.go b/vendor/github.com/klauspost/compress/gzip/gunzip.go deleted file mode 100644 index e73fab3f..00000000 --- a/vendor/github.com/klauspost/compress/gzip/gunzip.go +++ /dev/null @@ -1,344 +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 gzip implements reading and writing of gzip format compressed files, -// as specified in RFC 1952. -package gzip - -import ( - "bufio" - "encoding/binary" - "errors" - "io" - "time" - - "github.com/klauspost/compress/flate" - "github.com/klauspost/crc32" -) - -const ( - gzipID1 = 0x1f - gzipID2 = 0x8b - gzipDeflate = 8 - flagText = 1 << 0 - flagHdrCrc = 1 << 1 - flagExtra = 1 << 2 - flagName = 1 << 3 - flagComment = 1 << 4 -) - -var ( - // ErrChecksum is returned when reading GZIP data that has an invalid checksum. - ErrChecksum = errors.New("gzip: invalid checksum") - // ErrHeader is returned when reading GZIP data that has an invalid header. - ErrHeader = errors.New("gzip: invalid header") -) - -var le = binary.LittleEndian - -// noEOF converts io.EOF to io.ErrUnexpectedEOF. -func noEOF(err error) error { - if err == io.EOF { - return io.ErrUnexpectedEOF - } - return err -} - -// The gzip file stores a header giving metadata about the compressed file. -// That header is exposed as the fields of the Writer and Reader structs. -// -// Strings must be UTF-8 encoded and may only contain Unicode code points -// U+0001 through U+00FF, due to limitations of the GZIP file format. -type Header struct { - Comment string // comment - Extra []byte // "extra data" - ModTime time.Time // modification time - Name string // file name - OS byte // operating system type -} - -// A Reader is an io.Reader that can be read to retrieve -// uncompressed data from a gzip-format compressed file. -// -// In general, a gzip file can be a concatenation of gzip files, -// each with its own header. Reads from the Reader -// return the concatenation of the uncompressed data of each. -// Only the first header is recorded in the Reader fields. -// -// Gzip files store a length and checksum of the uncompressed data. -// The Reader will return a ErrChecksum when Read -// reaches the end of the uncompressed data if it does not -// have the expected length or checksum. Clients should treat data -// returned by Read as tentative until they receive the io.EOF -// marking the end of the data. -type Reader struct { - Header // valid after NewReader or Reader.Reset - r flate.Reader - decompressor io.ReadCloser - digest uint32 // CRC-32, IEEE polynomial (section 8) - size uint32 // Uncompressed size (section 2.3.1) - buf [512]byte - err error - multistream bool -} - -// NewReader creates a new Reader reading the given reader. -// If r does not also implement io.ByteReader, -// the decompressor may read more data than necessary from r. -// -// It is the caller's responsibility to call Close on the Reader when done. -// -// The Reader.Header fields will be valid in the Reader returned. -func NewReader(r io.Reader) (*Reader, error) { - z := new(Reader) - if err := z.Reset(r); err != nil { - return nil, err - } - return z, nil -} - -// Reset discards the Reader z's state and makes it equivalent to the -// result of its original state from NewReader, but reading from r instead. -// This permits reusing a Reader rather than allocating a new one. -func (z *Reader) Reset(r io.Reader) error { - *z = Reader{ - decompressor: z.decompressor, - multistream: true, - } - if rr, ok := r.(flate.Reader); ok { - z.r = rr - } else { - z.r = bufio.NewReader(r) - } - z.Header, z.err = z.readHeader() - return z.err -} - -// Multistream controls whether the reader supports multistream files. -// -// If enabled (the default), the Reader expects the input to be a sequence -// of individually gzipped data streams, each with its own header and -// trailer, ending at EOF. The effect is that the concatenation of a sequence -// of gzipped files is treated as equivalent to the gzip of the concatenation -// of the sequence. This is standard behavior for gzip readers. -// -// Calling Multistream(false) disables this behavior; disabling the behavior -// can be useful when reading file formats that distinguish individual gzip -// data streams or mix gzip data streams with other data streams. -// In this mode, when the Reader reaches the end of the data stream, -// Read returns io.EOF. If the underlying reader implements io.ByteReader, -// it will be left positioned just after the gzip stream. -// To start the next stream, call z.Reset(r) followed by z.Multistream(false). -// If there is no next stream, z.Reset(r) will return io.EOF. -func (z *Reader) Multistream(ok bool) { - z.multistream = ok -} - -// readString reads a NUL-terminated string from z.r. -// It treats the bytes read as being encoded as ISO 8859-1 (Latin-1) and -// will output a string encoded using UTF-8. -// This method always updates z.digest with the data read. -func (z *Reader) readString() (string, error) { - var err error - needConv := false - for i := 0; ; i++ { - if i >= len(z.buf) { - return "", ErrHeader - } - z.buf[i], err = z.r.ReadByte() - if err != nil { - return "", err - } - if z.buf[i] > 0x7f { - needConv = true - } - if z.buf[i] == 0 { - // Digest covers the NUL terminator. - z.digest = crc32.Update(z.digest, crc32.IEEETable, z.buf[:i+1]) - - // Strings are ISO 8859-1, Latin-1 (RFC 1952, section 2.3.1). - if needConv { - s := make([]rune, 0, i) - for _, v := range z.buf[:i] { - s = append(s, rune(v)) - } - return string(s), nil - } - return string(z.buf[:i]), nil - } - } -} - -// readHeader reads the GZIP header according to section 2.3.1. -// This method does not set z.err. -func (z *Reader) readHeader() (hdr Header, err error) { - if _, err = io.ReadFull(z.r, z.buf[:10]); err != nil { - // RFC 1952, section 2.2, says the following: - // A gzip file consists of a series of "members" (compressed data sets). - // - // Other than this, the specification does not clarify whether a - // "series" is defined as "one or more" or "zero or more". To err on the - // side of caution, Go interprets this to mean "zero or more". - // Thus, it is okay to return io.EOF here. - return hdr, err - } - if z.buf[0] != gzipID1 || z.buf[1] != gzipID2 || z.buf[2] != gzipDeflate { - return hdr, ErrHeader - } - flg := z.buf[3] - hdr.ModTime = time.Unix(int64(le.Uint32(z.buf[4:8])), 0) - // z.buf[8] is XFL and is currently ignored. - hdr.OS = z.buf[9] - z.digest = crc32.ChecksumIEEE(z.buf[:10]) - - if flg&flagExtra != 0 { - if _, err = io.ReadFull(z.r, z.buf[:2]); err != nil { - return hdr, noEOF(err) - } - z.digest = crc32.Update(z.digest, crc32.IEEETable, z.buf[:2]) - data := make([]byte, le.Uint16(z.buf[:2])) - if _, err = io.ReadFull(z.r, data); err != nil { - return hdr, noEOF(err) - } - z.digest = crc32.Update(z.digest, crc32.IEEETable, data) - hdr.Extra = data - } - - var s string - if flg&flagName != 0 { - if s, err = z.readString(); err != nil { - return hdr, err - } - hdr.Name = s - } - - if flg&flagComment != 0 { - if s, err = z.readString(); err != nil { - return hdr, err - } - hdr.Comment = s - } - - if flg&flagHdrCrc != 0 { - if _, err = io.ReadFull(z.r, z.buf[:2]); err != nil { - return hdr, noEOF(err) - } - digest := le.Uint16(z.buf[:2]) - if digest != uint16(z.digest) { - return hdr, ErrHeader - } - } - - z.digest = 0 - if z.decompressor == nil { - z.decompressor = flate.NewReader(z.r) - } else { - z.decompressor.(flate.Resetter).Reset(z.r, nil) - } - return hdr, nil -} - -// Read implements io.Reader, reading uncompressed bytes from its underlying Reader. -func (z *Reader) Read(p []byte) (n int, err error) { - if z.err != nil { - return 0, z.err - } - - n, z.err = z.decompressor.Read(p) - z.digest = crc32.Update(z.digest, crc32.IEEETable, p[:n]) - z.size += uint32(n) - if z.err != io.EOF { - // In the normal case we return here. - return n, z.err - } - - // Finished file; check checksum and size. - if _, err := io.ReadFull(z.r, z.buf[:8]); err != nil { - z.err = noEOF(err) - return n, z.err - } - digest := le.Uint32(z.buf[:4]) - size := le.Uint32(z.buf[4:8]) - if digest != z.digest || size != z.size { - z.err = ErrChecksum - return n, z.err - } - z.digest, z.size = 0, 0 - - // File is ok; check if there is another. - if !z.multistream { - return n, io.EOF - } - z.err = nil // Remove io.EOF - - if _, z.err = z.readHeader(); z.err != nil { - return n, z.err - } - - // Read from next file, if necessary. - if n > 0 { - return n, nil - } - return z.Read(p) -} - -// Support the io.WriteTo interface for io.Copy and friends. -func (z *Reader) WriteTo(w io.Writer) (int64, error) { - total := int64(0) - crcWriter := crc32.NewIEEE() - for { - if z.err != nil { - if z.err == io.EOF { - return total, nil - } - return total, z.err - } - - // We write both to output and digest. - mw := io.MultiWriter(w, crcWriter) - n, err := z.decompressor.(io.WriterTo).WriteTo(mw) - total += n - z.size += uint32(n) - if err != nil { - z.err = err - return total, z.err - } - - // Finished file; check checksum + size. - if _, err := io.ReadFull(z.r, z.buf[0:8]); err != nil { - if err == io.EOF { - err = io.ErrUnexpectedEOF - } - z.err = err - return total, err - } - z.digest = crcWriter.Sum32() - digest := le.Uint32(z.buf[:4]) - size := le.Uint32(z.buf[4:8]) - if digest != z.digest || size != z.size { - z.err = ErrChecksum - return total, z.err - } - z.digest, z.size = 0, 0 - - // File is ok; check if there is another. - if !z.multistream { - return total, nil - } - crcWriter.Reset() - z.err = nil // Remove io.EOF - - if _, z.err = z.readHeader(); z.err != nil { - if z.err == io.EOF { - return total, nil - } - return total, z.err - } - } -} - -// Close closes the Reader. It does not close the underlying io.Reader. -// In order for the GZIP checksum to be verified, the reader must be -// fully consumed until the io.EOF. -func (z *Reader) Close() error { return z.decompressor.Close() } |