diff options
Diffstat (limited to 'vendor/github.com/golang/snappy/decode.go')
| -rw-r--r-- | vendor/github.com/golang/snappy/decode.go | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/vendor/github.com/golang/snappy/decode.go b/vendor/github.com/golang/snappy/decode.go deleted file mode 100644 index 72efb03..0000000 --- a/vendor/github.com/golang/snappy/decode.go +++ /dev/null @@ -1,237 +0,0 @@ -// Copyright 2011 The Snappy-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 snappy - -import ( - "encoding/binary" - "errors" - "io" -) - -var ( - // ErrCorrupt reports that the input is invalid. - ErrCorrupt = errors.New("snappy: corrupt input") - // ErrTooLarge reports that the uncompressed length is too large. - ErrTooLarge = errors.New("snappy: decoded block is too large") - // ErrUnsupported reports that the input isn't supported. - ErrUnsupported = errors.New("snappy: unsupported input") - - errUnsupportedLiteralLength = errors.New("snappy: unsupported literal length") -) - -// DecodedLen returns the length of the decoded block. -func DecodedLen(src []byte) (int, error) { - v, _, err := decodedLen(src) - return v, err -} - -// decodedLen returns the length of the decoded block and the number of bytes -// that the length header occupied. -func decodedLen(src []byte) (blockLen, headerLen int, err error) { - v, n := binary.Uvarint(src) - if n <= 0 || v > 0xffffffff { - return 0, 0, ErrCorrupt - } - - const wordSize = 32 << (^uint(0) >> 32 & 1) - if wordSize == 32 && v > 0x7fffffff { - return 0, 0, ErrTooLarge - } - return int(v), n, nil -} - -const ( - decodeErrCodeCorrupt = 1 - decodeErrCodeUnsupportedLiteralLength = 2 -) - -// Decode returns the decoded form of src. The returned slice may be a sub- -// slice of dst if dst was large enough to hold the entire decoded block. -// Otherwise, a newly allocated slice will be returned. -// -// The dst and src must not overlap. It is valid to pass a nil dst. -func Decode(dst, src []byte) ([]byte, error) { - dLen, s, err := decodedLen(src) - if err != nil { - return nil, err - } - if dLen <= len(dst) { - dst = dst[:dLen] - } else { - dst = make([]byte, dLen) - } - switch decode(dst, src[s:]) { - case 0: - return dst, nil - case decodeErrCodeUnsupportedLiteralLength: - return nil, errUnsupportedLiteralLength - } - return nil, ErrCorrupt -} - -// NewReader returns a new Reader that decompresses from r, using the framing -// format described at -// https://github.com/google/snappy/blob/master/framing_format.txt -func NewReader(r io.Reader) *Reader { - return &Reader{ - r: r, - decoded: make([]byte, maxBlockSize), - buf: make([]byte, maxEncodedLenOfMaxBlockSize+checksumSize), - } -} - -// Reader is an io.Reader that can read Snappy-compressed bytes. -type Reader struct { - r io.Reader - err error - decoded []byte - buf []byte - // decoded[i:j] contains decoded bytes that have not yet been passed on. - i, j int - readHeader bool -} - -// Reset discards any buffered data, resets all state, and switches the Snappy -// reader to read from r. This permits reusing a Reader rather than allocating -// a new one. -func (r *Reader) Reset(reader io.Reader) { - r.r = reader - r.err = nil - r.i = 0 - r.j = 0 - r.readHeader = false -} - -func (r *Reader) readFull(p []byte, allowEOF bool) (ok bool) { - if _, r.err = io.ReadFull(r.r, p); r.err != nil { - if r.err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) { - r.err = ErrCorrupt - } - return false - } - return true -} - -// Read satisfies the io.Reader interface. -func (r *Reader) Read(p []byte) (int, error) { - if r.err != nil { - return 0, r.err - } - for { - if r.i < r.j { - n := copy(p, r.decoded[r.i:r.j]) - r.i += n - return n, nil - } - if !r.readFull(r.buf[:4], true) { - return 0, r.err - } - chunkType := r.buf[0] - if !r.readHeader { - if chunkType != chunkTypeStreamIdentifier { - r.err = ErrCorrupt - return 0, r.err - } - r.readHeader = true - } - chunkLen := int(r.buf[1]) | int(r.buf[2])<<8 | int(r.buf[3])<<16 - if chunkLen > len(r.buf) { - r.err = ErrUnsupported - return 0, r.err - } - - // The chunk types are specified at - // https://github.com/google/snappy/blob/master/framing_format.txt - switch chunkType { - case chunkTypeCompressedData: - // Section 4.2. Compressed data (chunk type 0x00). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return 0, r.err - } - buf := r.buf[:chunkLen] - if !r.readFull(buf, false) { - return 0, r.err - } - checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24 - buf = buf[checksumSize:] - - n, err := DecodedLen(buf) - if err != nil { - r.err = err - return 0, r.err - } - if n > len(r.decoded) { - r.err = ErrCorrupt - return 0, r.err - } - if _, err := Decode(r.decoded, buf); err != nil { - r.err = err - return 0, r.err - } - if crc(r.decoded[:n]) != checksum { - r.err = ErrCorrupt - return 0, r.err - } - r.i, r.j = 0, n - continue - - case chunkTypeUncompressedData: - // Section 4.3. Uncompressed data (chunk type 0x01). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return 0, r.err - } - buf := r.buf[:checksumSize] - if !r.readFull(buf, false) { - return 0, r.err - } - checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24 - // Read directly into r.decoded instead of via r.buf. - n := chunkLen - checksumSize - if n > len(r.decoded) { - r.err = ErrCorrupt - return 0, r.err - } - if !r.readFull(r.decoded[:n], false) { - return 0, r.err - } - if crc(r.decoded[:n]) != checksum { - r.err = ErrCorrupt - return 0, r.err - } - r.i, r.j = 0, n - continue - - case chunkTypeStreamIdentifier: - // Section 4.1. Stream identifier (chunk type 0xff). - if chunkLen != len(magicBody) { - r.err = ErrCorrupt - return 0, r.err - } - if !r.readFull(r.buf[:len(magicBody)], false) { - return 0, r.err - } - for i := 0; i < len(magicBody); i++ { - if r.buf[i] != magicBody[i] { - r.err = ErrCorrupt - return 0, r.err - } - } - continue - } - - if chunkType <= 0x7f { - // Section 4.5. Reserved unskippable chunks (chunk types 0x02-0x7f). - r.err = ErrUnsupported - return 0, r.err - } - // Section 4.4 Padding (chunk type 0xfe). - // Section 4.6. Reserved skippable chunks (chunk types 0x80-0xfd). - if !r.readFull(r.buf[:chunkLen], false) { - return 0, r.err - } - } -} |