diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/zlib/reader.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/zlib/reader.go | 183 |
1 files changed, 0 insertions, 183 deletions
diff --git a/vendor/github.com/klauspost/compress/zlib/reader.go b/vendor/github.com/klauspost/compress/zlib/reader.go deleted file mode 100644 index f127d4776..000000000 --- a/vendor/github.com/klauspost/compress/zlib/reader.go +++ /dev/null @@ -1,183 +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 zlib implements reading and writing of zlib format compressed data, -as specified in RFC 1950. - -The implementation provides filters that uncompress during reading -and compress during writing. For example, to write compressed data -to a buffer: - - var b bytes.Buffer - w := zlib.NewWriter(&b) - w.Write([]byte("hello, world\n")) - w.Close() - -and to read that data back: - - r, err := zlib.NewReader(&b) - io.Copy(os.Stdout, r) - r.Close() -*/ -package zlib - -import ( - "bufio" - "compress/zlib" - "hash" - "hash/adler32" - "io" - - "github.com/klauspost/compress/flate" -) - -const zlibDeflate = 8 - -var ( - // ErrChecksum is returned when reading ZLIB data that has an invalid checksum. - ErrChecksum = zlib.ErrChecksum - // ErrDictionary is returned when reading ZLIB data that has an invalid dictionary. - ErrDictionary = zlib.ErrDictionary - // ErrHeader is returned when reading ZLIB data that has an invalid header. - ErrHeader = zlib.ErrHeader -) - -type reader struct { - r flate.Reader - decompressor io.ReadCloser - digest hash.Hash32 - err error - scratch [4]byte -} - -// Resetter resets a ReadCloser returned by NewReader or NewReaderDict to -// to switch to a new underlying Reader. This permits reusing a ReadCloser -// instead of allocating a new one. -type Resetter interface { - // Reset discards any buffered data and resets the Resetter as if it was - // newly initialized with the given reader. - Reset(r io.Reader, dict []byte) error -} - -// NewReader creates a new ReadCloser. -// Reads from the returned ReadCloser read and decompress data from r. -// If r does not implement io.ByteReader, the decompressor may read more -// data than necessary from r. -// It is the caller's responsibility to call Close on the ReadCloser when done. -// -// The ReadCloser returned by NewReader also implements Resetter. -func NewReader(r io.Reader) (io.ReadCloser, error) { - return NewReaderDict(r, nil) -} - -// NewReaderDict is like NewReader but uses a preset dictionary. -// NewReaderDict ignores the dictionary if the compressed data does not refer to it. -// If the compressed data refers to a different dictionary, NewReaderDict returns ErrDictionary. -// -// The ReadCloser returned by NewReaderDict also implements Resetter. -func NewReaderDict(r io.Reader, dict []byte) (io.ReadCloser, error) { - z := new(reader) - err := z.Reset(r, dict) - if err != nil { - return nil, err - } - return z, nil -} - -func (z *reader) Read(p []byte) (int, error) { - if z.err != nil { - return 0, z.err - } - - var n int - n, z.err = z.decompressor.Read(p) - z.digest.Write(p[0:n]) - if z.err != io.EOF { - // In the normal case we return here. - return n, z.err - } - - // Finished file; check checksum. - if _, err := io.ReadFull(z.r, z.scratch[0:4]); err != nil { - if err == io.EOF { - err = io.ErrUnexpectedEOF - } - z.err = err - return n, z.err - } - // ZLIB (RFC 1950) is big-endian, unlike GZIP (RFC 1952). - checksum := uint32(z.scratch[0])<<24 | uint32(z.scratch[1])<<16 | uint32(z.scratch[2])<<8 | uint32(z.scratch[3]) - if checksum != z.digest.Sum32() { - z.err = ErrChecksum - return n, z.err - } - return n, io.EOF -} - -// Calling Close does not close the wrapped io.Reader originally passed to NewReader. -// In order for the ZLIB checksum to be verified, the reader must be -// fully consumed until the io.EOF. -func (z *reader) Close() error { - if z.err != nil && z.err != io.EOF { - return z.err - } - z.err = z.decompressor.Close() - return z.err -} - -func (z *reader) Reset(r io.Reader, dict []byte) error { - *z = reader{decompressor: z.decompressor, digest: z.digest} - if fr, ok := r.(flate.Reader); ok { - z.r = fr - } else { - z.r = bufio.NewReader(r) - } - - // Read the header (RFC 1950 section 2.2.). - _, z.err = io.ReadFull(z.r, z.scratch[0:2]) - if z.err != nil { - if z.err == io.EOF { - z.err = io.ErrUnexpectedEOF - } - return z.err - } - h := uint(z.scratch[0])<<8 | uint(z.scratch[1]) - if (z.scratch[0]&0x0f != zlibDeflate) || (h%31 != 0) { - z.err = ErrHeader - return z.err - } - haveDict := z.scratch[1]&0x20 != 0 - if haveDict { - _, z.err = io.ReadFull(z.r, z.scratch[0:4]) - if z.err != nil { - if z.err == io.EOF { - z.err = io.ErrUnexpectedEOF - } - return z.err - } - checksum := uint32(z.scratch[0])<<24 | uint32(z.scratch[1])<<16 | uint32(z.scratch[2])<<8 | uint32(z.scratch[3]) - if checksum != adler32.Checksum(dict) { - z.err = ErrDictionary - return z.err - } - } - - if z.decompressor == nil { - if haveDict { - z.decompressor = flate.NewReaderDict(z.r, dict) - } else { - z.decompressor = flate.NewReader(z.r) - } - } else { - z.decompressor.(flate.Resetter).Reset(z.r, dict) - } - - if z.digest != nil { - z.digest.Reset() - } else { - z.digest = adler32.New() - } - return nil -} |