[VOL-1386] This commit add "dep" as the package management tool
for voltha-go.
Change-Id: I52bc4911dd00a441756ec7c30f46d45091f3f90e
diff --git a/vendor/github.com/pierrec/lz4/reader.go b/vendor/github.com/pierrec/lz4/reader.go
new file mode 100644
index 0000000..f08db47
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/reader.go
@@ -0,0 +1,295 @@
+package lz4
+
+import (
+ "encoding/binary"
+ "fmt"
+ "io"
+ "io/ioutil"
+
+ "github.com/pierrec/lz4/internal/xxh32"
+)
+
+// Reader implements the LZ4 frame decoder.
+// The Header is set after the first call to Read().
+// The Header may change between Read() calls in case of concatenated frames.
+type Reader struct {
+ Header
+
+ buf [8]byte // Scrap buffer.
+ pos int64 // Current position in src.
+ src io.Reader // Source.
+ zdata []byte // Compressed data.
+ data []byte // Uncompressed data.
+ idx int // Index of unread bytes into data.
+ checksum xxh32.XXHZero // Frame hash.
+}
+
+// NewReader returns a new LZ4 frame decoder.
+// No access to the underlying io.Reader is performed.
+func NewReader(src io.Reader) *Reader {
+ r := &Reader{src: src}
+ return r
+}
+
+// readHeader checks the frame magic number and parses the frame descriptoz.
+// Skippable frames are supported even as a first frame although the LZ4
+// specifications recommends skippable frames not to be used as first frames.
+func (z *Reader) readHeader(first bool) error {
+ defer z.checksum.Reset()
+
+ buf := z.buf[:]
+ for {
+ magic, err := z.readUint32()
+ if err != nil {
+ z.pos += 4
+ if !first && err == io.ErrUnexpectedEOF {
+ return io.EOF
+ }
+ return err
+ }
+ if magic == frameMagic {
+ break
+ }
+ if magic>>8 != frameSkipMagic>>8 {
+ return ErrInvalid
+ }
+ skipSize, err := z.readUint32()
+ if err != nil {
+ return err
+ }
+ z.pos += 4
+ m, err := io.CopyN(ioutil.Discard, z.src, int64(skipSize))
+ if err != nil {
+ return err
+ }
+ z.pos += m
+ }
+
+ // Header.
+ if _, err := io.ReadFull(z.src, buf[:2]); err != nil {
+ return err
+ }
+ z.pos += 8
+
+ b := buf[0]
+ if v := b >> 6; v != Version {
+ return fmt.Errorf("lz4: invalid version: got %d; expected %d", v, Version)
+ }
+ if b>>5&1 == 0 {
+ return fmt.Errorf("lz4: block dependency not supported")
+ }
+ z.BlockChecksum = b>>4&1 > 0
+ frameSize := b>>3&1 > 0
+ z.NoChecksum = b>>2&1 == 0
+
+ bmsID := buf[1] >> 4 & 0x7
+ bSize, ok := bsMapID[bmsID]
+ if !ok {
+ return fmt.Errorf("lz4: invalid block max size ID: %d", bmsID)
+ }
+ z.BlockMaxSize = bSize
+
+ // Allocate the compressed/uncompressed buffers.
+ // The compressed buffer cannot exceed the uncompressed one.
+ if n := 2 * bSize; cap(z.zdata) < n {
+ z.zdata = make([]byte, n, n)
+ }
+ if debugFlag {
+ debug("header block max size id=%d size=%d", bmsID, bSize)
+ }
+ z.zdata = z.zdata[:bSize]
+ z.data = z.zdata[:cap(z.zdata)][bSize:]
+ z.idx = len(z.data)
+
+ z.checksum.Write(buf[0:2])
+
+ if frameSize {
+ buf := buf[:8]
+ if _, err := io.ReadFull(z.src, buf); err != nil {
+ return err
+ }
+ z.Size = binary.LittleEndian.Uint64(buf)
+ z.pos += 8
+ z.checksum.Write(buf)
+ }
+
+ // Header checksum.
+ if _, err := io.ReadFull(z.src, buf[:1]); err != nil {
+ return err
+ }
+ z.pos++
+ if h := byte(z.checksum.Sum32() >> 8 & 0xFF); h != buf[0] {
+ return fmt.Errorf("lz4: invalid header checksum: got %x; expected %x", buf[0], h)
+ }
+
+ z.Header.done = true
+ if debugFlag {
+ debug("header read: %v", z.Header)
+ }
+
+ return nil
+}
+
+// Read decompresses data from the underlying source into the supplied buffer.
+//
+// Since there can be multiple streams concatenated, Header values may
+// change between calls to Read(). If that is the case, no data is actually read from
+// the underlying io.Reader, to allow for potential input buffer resizing.
+func (z *Reader) Read(buf []byte) (int, error) {
+ if debugFlag {
+ debug("Read buf len=%d", len(buf))
+ }
+ if !z.Header.done {
+ if err := z.readHeader(true); err != nil {
+ return 0, err
+ }
+ if debugFlag {
+ debug("header read OK compressed buffer %d / %d uncompressed buffer %d : %d index=%d",
+ len(z.zdata), cap(z.zdata), len(z.data), cap(z.data), z.idx)
+ }
+ }
+
+ if len(buf) == 0 {
+ return 0, nil
+ }
+
+ if z.idx == len(z.data) {
+ // No data ready for reading, process the next block.
+ if debugFlag {
+ debug("reading block from writer")
+ }
+ // Block length: 0 = end of frame, highest bit set: uncompressed.
+ bLen, err := z.readUint32()
+ if err != nil {
+ return 0, err
+ }
+ z.pos += 4
+
+ if bLen == 0 {
+ // End of frame reached.
+ if !z.NoChecksum {
+ // Validate the frame checksum.
+ checksum, err := z.readUint32()
+ if err != nil {
+ return 0, err
+ }
+ if debugFlag {
+ debug("frame checksum got=%x / want=%x", z.checksum.Sum32(), checksum)
+ }
+ z.pos += 4
+ if h := z.checksum.Sum32(); checksum != h {
+ return 0, fmt.Errorf("lz4: invalid frame checksum: got %x; expected %x", h, checksum)
+ }
+ }
+
+ // Get ready for the next concatenated frame and keep the position.
+ pos := z.pos
+ z.Reset(z.src)
+ z.pos = pos
+
+ // Since multiple frames can be concatenated, check for more.
+ return 0, z.readHeader(false)
+ }
+
+ if debugFlag {
+ debug("raw block size %d", bLen)
+ }
+ if bLen&compressedBlockFlag > 0 {
+ // Uncompressed block.
+ bLen &= compressedBlockMask
+ if debugFlag {
+ debug("uncompressed block size %d", bLen)
+ }
+ if int(bLen) > cap(z.data) {
+ return 0, fmt.Errorf("lz4: invalid block size: %d", bLen)
+ }
+ z.data = z.data[:bLen]
+ if _, err := io.ReadFull(z.src, z.data); err != nil {
+ return 0, err
+ }
+ z.pos += int64(bLen)
+
+ if z.BlockChecksum {
+ checksum, err := z.readUint32()
+ if err != nil {
+ return 0, err
+ }
+ z.pos += 4
+
+ if h := xxh32.ChecksumZero(z.data); h != checksum {
+ return 0, fmt.Errorf("lz4: invalid block checksum: got %x; expected %x", h, checksum)
+ }
+ }
+
+ } else {
+ // Compressed block.
+ if debugFlag {
+ debug("compressed block size %d", bLen)
+ }
+ if int(bLen) > cap(z.data) {
+ return 0, fmt.Errorf("lz4: invalid block size: %d", bLen)
+ }
+ zdata := z.zdata[:bLen]
+ if _, err := io.ReadFull(z.src, zdata); err != nil {
+ return 0, err
+ }
+ z.pos += int64(bLen)
+
+ if z.BlockChecksum {
+ checksum, err := z.readUint32()
+ if err != nil {
+ return 0, err
+ }
+ z.pos += 4
+
+ if h := xxh32.ChecksumZero(zdata); h != checksum {
+ return 0, fmt.Errorf("lz4: invalid block checksum: got %x; expected %x", h, checksum)
+ }
+ }
+
+ n, err := UncompressBlock(zdata, z.data)
+ if err != nil {
+ return 0, err
+ }
+ z.data = z.data[:n]
+ }
+
+ if !z.NoChecksum {
+ z.checksum.Write(z.data)
+ if debugFlag {
+ debug("current frame checksum %x", z.checksum.Sum32())
+ }
+ }
+ z.idx = 0
+ }
+
+ n := copy(buf, z.data[z.idx:])
+ z.idx += n
+ if debugFlag {
+ debug("copied %d bytes to input", n)
+ }
+
+ return n, nil
+}
+
+// Reset discards the Reader'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) {
+ z.Header = Header{}
+ z.pos = 0
+ z.src = r
+ z.zdata = z.zdata[:0]
+ z.data = z.data[:0]
+ z.idx = 0
+ z.checksum.Reset()
+}
+
+// readUint32 reads an uint32 into the supplied buffer.
+// The idea is to make use of the already allocated buffers avoiding additional allocations.
+func (z *Reader) readUint32() (uint32, error) {
+ buf := z.buf[:4]
+ _, err := io.ReadFull(z.src, buf)
+ x := binary.LittleEndian.Uint32(buf)
+ return x, err
+}