diff options
Diffstat (limited to 'vendor/github.com/klauspost/compress/s2/decode.go')
| -rw-r--r-- | vendor/github.com/klauspost/compress/s2/decode.go | 762 |
1 files changed, 0 insertions, 762 deletions
diff --git a/vendor/github.com/klauspost/compress/s2/decode.go b/vendor/github.com/klauspost/compress/s2/decode.go deleted file mode 100644 index 9e7fce885..000000000 --- a/vendor/github.com/klauspost/compress/s2/decode.go +++ /dev/null @@ -1,762 +0,0 @@ -// Copyright 2011 The Snappy-Go Authors. All rights reserved. -// Copyright (c) 2019 Klaus Post. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package s2 - -import ( - "encoding/binary" - "errors" - "fmt" - "io" - "io/ioutil" -) - -var ( - // ErrCorrupt reports that the input is invalid. - ErrCorrupt = errors.New("s2: corrupt input") - // ErrCRC reports that the input failed CRC validation (streams only) - ErrCRC = errors.New("s2: corrupt input, crc mismatch") - // ErrTooLarge reports that the uncompressed length is too large. - ErrTooLarge = errors.New("s2: decoded block is too large") - // ErrUnsupported reports that the input isn't supported. - ErrUnsupported = errors.New("s2: unsupported input") -) - -// ErrCantSeek is returned if the stream cannot be seeked. -type ErrCantSeek struct { - Reason string -} - -// Error returns the error as string. -func (e ErrCantSeek) Error() string { - return fmt.Sprintf("s2: Can't seek because %s", e.Reason) -} - -// 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 -) - -// 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 <= cap(dst) { - dst = dst[:dLen] - } else { - dst = make([]byte, dLen) - } - if s2Decode(dst, src[s:]) != 0 { - return nil, ErrCorrupt - } - return dst, nil -} - -// 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 with S2 changes. -func NewReader(r io.Reader, opts ...ReaderOption) *Reader { - nr := Reader{ - r: r, - maxBlock: maxBlockSize, - } - for _, opt := range opts { - if err := opt(&nr); err != nil { - nr.err = err - return &nr - } - } - nr.maxBufSize = MaxEncodedLen(nr.maxBlock) + checksumSize - if nr.lazyBuf > 0 { - nr.buf = make([]byte, MaxEncodedLen(nr.lazyBuf)+checksumSize) - } else { - nr.buf = make([]byte, MaxEncodedLen(defaultBlockSize)+checksumSize) - } - nr.readHeader = nr.ignoreStreamID - nr.paramsOK = true - return &nr -} - -// ReaderOption is an option for creating a decoder. -type ReaderOption func(*Reader) error - -// ReaderMaxBlockSize allows to control allocations if the stream -// has been compressed with a smaller WriterBlockSize, or with the default 1MB. -// Blocks must be this size or smaller to decompress, -// otherwise the decoder will return ErrUnsupported. -// -// For streams compressed with Snappy this can safely be set to 64KB (64 << 10). -// -// Default is the maximum limit of 4MB. -func ReaderMaxBlockSize(blockSize int) ReaderOption { - return func(r *Reader) error { - if blockSize > maxBlockSize || blockSize <= 0 { - return errors.New("s2: block size too large. Must be <= 4MB and > 0") - } - if r.lazyBuf == 0 && blockSize < defaultBlockSize { - r.lazyBuf = blockSize - } - r.maxBlock = blockSize - return nil - } -} - -// ReaderAllocBlock allows to control upfront stream allocations -// and not allocate for frames bigger than this initially. -// If frames bigger than this is seen a bigger buffer will be allocated. -// -// Default is 1MB, which is default output size. -func ReaderAllocBlock(blockSize int) ReaderOption { - return func(r *Reader) error { - if blockSize > maxBlockSize || blockSize < 1024 { - return errors.New("s2: invalid ReaderAllocBlock. Must be <= 4MB and >= 1024") - } - r.lazyBuf = blockSize - return nil - } -} - -// ReaderIgnoreStreamIdentifier will make the reader skip the expected -// stream identifier at the beginning of the stream. -// This can be used when serving a stream that has been forwarded to a specific point. -func ReaderIgnoreStreamIdentifier() ReaderOption { - return func(r *Reader) error { - r.ignoreStreamID = true - return nil - } -} - -// ReaderSkippableCB will register a callback for chuncks with the specified ID. -// ID must be a Reserved skippable chunks ID, 0x80-0xfd (inclusive). -// For each chunk with the ID, the callback is called with the content. -// Any returned non-nil error will abort decompression. -// Only one callback per ID is supported, latest sent will be used. -func ReaderSkippableCB(id uint8, fn func(r io.Reader) error) ReaderOption { - return func(r *Reader) error { - if id < 0x80 || id > 0xfd { - return fmt.Errorf("ReaderSkippableCB: Invalid id provided, must be 0x80-0xfd (inclusive)") - } - r.skippableCB[id] = fn - return nil - } -} - -// Reader is an io.Reader that can read Snappy-compressed bytes. -type Reader struct { - r io.Reader - err error - decoded []byte - buf []byte - skippableCB [0x80]func(r io.Reader) error - blockStart int64 // Uncompressed offset at start of current. - index *Index - - // decoded[i:j] contains decoded bytes that have not yet been passed on. - i, j int - // maximum block size allowed. - maxBlock int - // maximum expected buffer size. - maxBufSize int - // alloc a buffer this size if > 0. - lazyBuf int - readHeader bool - paramsOK bool - snappyFrame bool - ignoreStreamID bool -} - -// ensureBufferSize will ensure that the buffer can take at least n bytes. -// If false is returned the buffer exceeds maximum allowed size. -func (r *Reader) ensureBufferSize(n int) bool { - if len(r.buf) >= n { - return true - } - if n > r.maxBufSize { - r.err = ErrCorrupt - return false - } - // Realloc buffer. - r.buf = make([]byte, n) - return true -} - -// 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) { - if !r.paramsOK { - return - } - r.index = nil - r.r = reader - r.err = nil - r.i = 0 - r.j = 0 - r.readHeader = r.ignoreStreamID -} - -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 -} - -// skippable will skip n bytes. -// If the supplied reader supports seeking that is used. -// tmp is used as a temporary buffer for reading. -// The supplied slice does not need to be the size of the read. -func (r *Reader) skippable(tmp []byte, n int, allowEOF bool, id uint8) (ok bool) { - if id < 0x80 { - r.err = fmt.Errorf("interbal error: skippable id < 0x80") - return false - } - if fn := r.skippableCB[id-0x80]; fn != nil { - rd := io.LimitReader(r.r, int64(n)) - r.err = fn(rd) - if r.err != nil { - return false - } - _, r.err = io.CopyBuffer(ioutil.Discard, rd, tmp) - return r.err == nil - } - if rs, ok := r.r.(io.ReadSeeker); ok { - _, err := rs.Seek(int64(n), io.SeekCurrent) - if err == nil { - return true - } - if err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) { - r.err = ErrCorrupt - return false - } - } - for n > 0 { - if n < len(tmp) { - tmp = tmp[:n] - } - if _, r.err = io.ReadFull(r.r, tmp); r.err != nil { - if r.err == io.ErrUnexpectedEOF || (r.err == io.EOF && !allowEOF) { - r.err = ErrCorrupt - } - return false - } - n -= len(tmp) - } - 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 - - // The chunk types are specified at - // https://github.com/google/snappy/blob/master/framing_format.txt - switch chunkType { - case chunkTypeCompressedData: - r.blockStart += int64(r.j) - // Section 4.2. Compressed data (chunk type 0x00). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return 0, r.err - } - if !r.ensureBufferSize(chunkLen) { - if r.err == nil { - r.err = ErrUnsupported - } - 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 r.snappyFrame && n > maxSnappyBlockSize { - r.err = ErrCorrupt - return 0, r.err - } - - if n > len(r.decoded) { - if n > r.maxBlock { - r.err = ErrCorrupt - return 0, r.err - } - r.decoded = make([]byte, n) - } - if _, err := Decode(r.decoded, buf); err != nil { - r.err = err - return 0, r.err - } - if crc(r.decoded[:n]) != checksum { - r.err = ErrCRC - return 0, r.err - } - r.i, r.j = 0, n - continue - - case chunkTypeUncompressedData: - r.blockStart += int64(r.j) - // Section 4.3. Uncompressed data (chunk type 0x01). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return 0, r.err - } - if !r.ensureBufferSize(chunkLen) { - if r.err == nil { - r.err = ErrUnsupported - } - 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 r.snappyFrame && n > maxSnappyBlockSize { - r.err = ErrCorrupt - return 0, r.err - } - if n > len(r.decoded) { - if n > r.maxBlock { - r.err = ErrCorrupt - return 0, r.err - } - r.decoded = make([]byte, n) - } - if !r.readFull(r.decoded[:n], false) { - return 0, r.err - } - if crc(r.decoded[:n]) != checksum { - r.err = ErrCRC - 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 - } - if string(r.buf[:len(magicBody)]) != magicBody { - if string(r.buf[:len(magicBody)]) != magicBodySnappy { - r.err = ErrCorrupt - return 0, r.err - } else { - r.snappyFrame = true - } - } else { - r.snappyFrame = false - } - continue - } - - if chunkType <= 0x7f { - // Section 4.5. Reserved unskippable chunks (chunk types 0x02-0x7f). - // fmt.Printf("ERR chunktype: 0x%x\n", chunkType) - 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 chunkLen > maxChunkSize { - // fmt.Printf("ERR chunkLen: 0x%x\n", chunkLen) - r.err = ErrUnsupported - return 0, r.err - } - - // fmt.Printf("skippable: ID: 0x%x, len: 0x%x\n", chunkType, chunkLen) - if !r.skippable(r.buf, chunkLen, false, chunkType) { - return 0, r.err - } - } -} - -// Skip will skip n bytes forward in the decompressed output. -// For larger skips this consumes less CPU and is faster than reading output and discarding it. -// CRC is not checked on skipped blocks. -// io.ErrUnexpectedEOF is returned if the stream ends before all bytes have been skipped. -// If a decoding error is encountered subsequent calls to Read will also fail. -func (r *Reader) Skip(n int64) error { - if n < 0 { - return errors.New("attempted negative skip") - } - if r.err != nil { - return r.err - } - - for n > 0 { - if r.i < r.j { - // Skip in buffer. - // decoded[i:j] contains decoded bytes that have not yet been passed on. - left := int64(r.j - r.i) - if left >= n { - r.i += int(n) - return nil - } - n -= int64(r.j - r.i) - r.i = r.j - } - - // Buffer empty; read blocks until we have content. - if !r.readFull(r.buf[:4], true) { - if r.err == io.EOF { - r.err = io.ErrUnexpectedEOF - } - return r.err - } - chunkType := r.buf[0] - if !r.readHeader { - if chunkType != chunkTypeStreamIdentifier { - r.err = ErrCorrupt - return r.err - } - r.readHeader = true - } - chunkLen := int(r.buf[1]) | int(r.buf[2])<<8 | int(r.buf[3])<<16 - - // The chunk types are specified at - // https://github.com/google/snappy/blob/master/framing_format.txt - switch chunkType { - case chunkTypeCompressedData: - r.blockStart += int64(r.j) - // Section 4.2. Compressed data (chunk type 0x00). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return r.err - } - if !r.ensureBufferSize(chunkLen) { - if r.err == nil { - r.err = ErrUnsupported - } - return r.err - } - buf := r.buf[:chunkLen] - if !r.readFull(buf, false) { - return r.err - } - checksum := uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24 - buf = buf[checksumSize:] - - dLen, err := DecodedLen(buf) - if err != nil { - r.err = err - return r.err - } - if dLen > r.maxBlock { - r.err = ErrCorrupt - return r.err - } - // Check if destination is within this block - if int64(dLen) > n { - if len(r.decoded) < dLen { - r.decoded = make([]byte, dLen) - } - if _, err := Decode(r.decoded, buf); err != nil { - r.err = err - return r.err - } - if crc(r.decoded[:dLen]) != checksum { - r.err = ErrCorrupt - return r.err - } - } else { - // Skip block completely - n -= int64(dLen) - dLen = 0 - } - r.i, r.j = 0, dLen - continue - case chunkTypeUncompressedData: - r.blockStart += int64(r.j) - // Section 4.3. Uncompressed data (chunk type 0x01). - if chunkLen < checksumSize { - r.err = ErrCorrupt - return r.err - } - if !r.ensureBufferSize(chunkLen) { - if r.err != nil { - r.err = ErrUnsupported - } - return r.err - } - buf := r.buf[:checksumSize] - if !r.readFull(buf, false) { - return 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. - n2 := chunkLen - checksumSize - if n2 > len(r.decoded) { - if n2 > r.maxBlock { - r.err = ErrCorrupt - return r.err - } - r.decoded = make([]byte, n2) - } - if !r.readFull(r.decoded[:n2], false) { - return r.err - } - if int64(n2) < n { - if crc(r.decoded[:n2]) != checksum { - r.err = ErrCorrupt - return r.err - } - } - r.i, r.j = 0, n2 - continue - case chunkTypeStreamIdentifier: - // Section 4.1. Stream identifier (chunk type 0xff). - if chunkLen != len(magicBody) { - r.err = ErrCorrupt - return r.err - } - if !r.readFull(r.buf[:len(magicBody)], false) { - return r.err - } - if string(r.buf[:len(magicBody)]) != magicBody { - if string(r.buf[:len(magicBody)]) != magicBodySnappy { - r.err = ErrCorrupt - return r.err - } - } - - continue - } - - if chunkType <= 0x7f { - // Section 4.5. Reserved unskippable chunks (chunk types 0x02-0x7f). - r.err = ErrUnsupported - return r.err - } - if chunkLen > maxChunkSize { - r.err = ErrUnsupported - return r.err - } - // Section 4.4 Padding (chunk type 0xfe). - // Section 4.6. Reserved skippable chunks (chunk types 0x80-0xfd). - if !r.skippable(r.buf, chunkLen, false, chunkType) { - return r.err - } - } - return nil -} - -// ReadSeeker provides random or forward seeking in compressed content. -// See Reader.ReadSeeker -type ReadSeeker struct { - *Reader -} - -// ReadSeeker will return an io.ReadSeeker compatible version of the reader. -// If 'random' is specified the returned io.Seeker can be used for -// random seeking, otherwise only forward seeking is supported. -// Enabling random seeking requires the original input to support -// the io.Seeker interface. -// A custom index can be specified which will be used if supplied. -// When using a custom index, it will not be read from the input stream. -// The returned ReadSeeker contains a shallow reference to the existing Reader, -// meaning changes performed to one is reflected in the other. -func (r *Reader) ReadSeeker(random bool, index []byte) (*ReadSeeker, error) { - // Read index if provided. - if len(index) != 0 { - if r.index == nil { - r.index = &Index{} - } - if _, err := r.index.Load(index); err != nil { - return nil, ErrCantSeek{Reason: "loading index returned: " + err.Error()} - } - } - - // Check if input is seekable - rs, ok := r.r.(io.ReadSeeker) - if !ok { - if !random { - return &ReadSeeker{Reader: r}, nil - } - return nil, ErrCantSeek{Reason: "input stream isn't seekable"} - } - - if r.index != nil { - // Seekable and index, ok... - return &ReadSeeker{Reader: r}, nil - } - - // Load from stream. - r.index = &Index{} - - // Read current position. - pos, err := rs.Seek(0, io.SeekCurrent) - if err != nil { - return nil, ErrCantSeek{Reason: "seeking input returned: " + err.Error()} - } - err = r.index.LoadStream(rs) - if err != nil { - if err == ErrUnsupported { - return nil, ErrCantSeek{Reason: "input stream does not contain an index"} - } - return nil, ErrCantSeek{Reason: "reading index returned: " + err.Error()} - } - - // reset position. - _, err = rs.Seek(pos, io.SeekStart) - if err != nil { - return nil, ErrCantSeek{Reason: "seeking input returned: " + err.Error()} - } - return &ReadSeeker{Reader: r}, nil -} - -// Seek allows seeking in compressed data. -func (r *ReadSeeker) Seek(offset int64, whence int) (int64, error) { - if r.err != nil { - return 0, r.err - } - if offset == 0 && whence == io.SeekCurrent { - return r.blockStart + int64(r.i), nil - } - if !r.readHeader { - // Make sure we read the header. - _, r.err = r.Read([]byte{}) - } - rs, ok := r.r.(io.ReadSeeker) - if r.index == nil || !ok { - if whence == io.SeekCurrent && offset >= 0 { - err := r.Skip(offset) - return r.blockStart + int64(r.i), err - } - if whence == io.SeekStart && offset >= r.blockStart+int64(r.i) { - err := r.Skip(offset - r.blockStart - int64(r.i)) - return r.blockStart + int64(r.i), err - } - return 0, ErrUnsupported - - } - - switch whence { - case io.SeekCurrent: - offset += r.blockStart + int64(r.i) - case io.SeekEnd: - offset = -offset - } - c, u, err := r.index.Find(offset) - if err != nil { - return r.blockStart + int64(r.i), err - } - - // Seek to next block - _, err = rs.Seek(c, io.SeekStart) - if err != nil { - return 0, err - } - - if offset < 0 { - offset = r.index.TotalUncompressed + offset - } - - r.i = r.j // Remove rest of current block. - if u < offset { - // Forward inside block - return offset, r.Skip(offset - u) - } - return offset, nil -} - -// ReadByte satisfies the io.ByteReader interface. -func (r *Reader) ReadByte() (byte, error) { - if r.err != nil { - return 0, r.err - } - if r.i < r.j { - c := r.decoded[r.i] - r.i++ - return c, nil - } - var tmp [1]byte - for i := 0; i < 10; i++ { - n, err := r.Read(tmp[:]) - if err != nil { - return 0, err - } - if n == 1 { - return tmp[0], nil - } - } - return 0, io.ErrNoProgress -} - -// SkippableCB will register a callback for chunks with the specified ID. -// ID must be a Reserved skippable chunks ID, 0x80-0xfe (inclusive). -// For each chunk with the ID, the callback is called with the content. -// Any returned non-nil error will abort decompression. -// Only one callback per ID is supported, latest sent will be used. -// Sending a nil function will disable previous callbacks. -func (r *Reader) SkippableCB(id uint8, fn func(r io.Reader) error) error { - if id < 0x80 || id > chunkTypePadding { - return fmt.Errorf("ReaderSkippableCB: Invalid id provided, must be 0x80-0xfe (inclusive)") - } - r.skippableCB[id] = fn - return nil -} |