[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/pierrec/lz4/reader_legacy.go b/vendor/github.com/pierrec/lz4/reader_legacy.go
new file mode 100644
index 0000000..1670a77
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/reader_legacy.go
@@ -0,0 +1,207 @@
+package lz4
+
+import (
+ "encoding/binary"
+ "fmt"
+ "io"
+)
+
+// ReaderLegacy implements the LZ4Demo frame decoder.
+// The Header is set after the first call to Read().
+type ReaderLegacy struct {
+ Header
+ // Handler called when a block has been successfully read.
+ // It provides the number of bytes read.
+ OnBlockDone func(size int)
+
+ lastBlock bool
+ 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.
+ skip int64 // Bytes to skip before next read.
+ dpos int64 // Position in dest
+}
+
+// NewReaderLegacy returns a new LZ4Demo frame decoder.
+// No access to the underlying io.Reader is performed.
+func NewReaderLegacy(src io.Reader) *ReaderLegacy {
+ r := &ReaderLegacy{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 *ReaderLegacy) readLegacyHeader() error {
+ z.lastBlock = false
+ magic, err := z.readUint32()
+ if err != nil {
+ z.pos += 4
+ if err == io.ErrUnexpectedEOF {
+ return io.EOF
+ }
+ return err
+ }
+ if magic != frameMagicLegacy {
+ return ErrInvalid
+ }
+ z.pos += 4
+
+ // Legacy has fixed 8MB blocksizes
+ // https://github.com/lz4/lz4/blob/dev/doc/lz4_Frame_format.md#legacy-frame
+ bSize := blockSize4M * 2
+
+ // 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 size=%d", bSize)
+ }
+ z.zdata = z.zdata[:bSize]
+ z.data = z.zdata[:cap(z.zdata)][bSize:]
+ z.idx = len(z.data)
+
+ 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 *ReaderLegacy) Read(buf []byte) (int, error) {
+ if debugFlag {
+ debug("Read buf len=%d", len(buf))
+ }
+ if !z.Header.done {
+ if err := z.readLegacyHeader(); 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 %d %d", z.idx, blockSize4M*2)
+ }
+
+ // Reset uncompressed buffer
+ z.data = z.zdata[:cap(z.zdata)][len(z.zdata):]
+
+ bLen, err := z.readUint32()
+ if err != nil {
+ return 0, err
+ }
+ if debugFlag {
+ debug(" bLen %d (0x%x) offset = %d (0x%x)", bLen, bLen, z.pos, z.pos)
+ }
+ z.pos += 4
+
+ // Legacy blocks are always compressed, even when detrimental
+ 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)
+
+ n, err := UncompressBlock(zdata, z.data)
+ if err != nil {
+ return 0, err
+ }
+
+ z.data = z.data[:n]
+ if z.OnBlockDone != nil {
+ z.OnBlockDone(n)
+ }
+
+ z.idx = 0
+
+ // Legacy blocks are fixed to 8MB, if we read a decompressed block smaller than this
+ // it means we've reached the end...
+ if n < blockSize4M*2 {
+ z.lastBlock = true
+ }
+ }
+
+ if z.skip > int64(len(z.data[z.idx:])) {
+ z.skip -= int64(len(z.data[z.idx:]))
+ z.dpos += int64(len(z.data[z.idx:]))
+ z.idx = len(z.data)
+ return 0, nil
+ }
+
+ z.idx += int(z.skip)
+ z.dpos += z.skip
+ z.skip = 0
+
+ n := copy(buf, z.data[z.idx:])
+ z.idx += n
+ z.dpos += int64(n)
+ if debugFlag {
+ debug("%v] copied %d bytes to input (%d:%d)", z.lastBlock, n, z.idx, len(z.data))
+ }
+ if z.lastBlock && len(z.data) == z.idx {
+ return n, io.EOF
+ }
+ return n, nil
+}
+
+// Seek implements io.Seeker, but supports seeking forward from the current
+// position only. Any other seek will return an error. Allows skipping output
+// bytes which aren't needed, which in some scenarios is faster than reading
+// and discarding them.
+// Note this may cause future calls to Read() to read 0 bytes if all of the
+// data they would have returned is skipped.
+func (z *ReaderLegacy) Seek(offset int64, whence int) (int64, error) {
+ if offset < 0 || whence != io.SeekCurrent {
+ return z.dpos + z.skip, ErrUnsupportedSeek
+ }
+ z.skip += offset
+ return z.dpos + z.skip, 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 *ReaderLegacy) 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
+}
+
+// readUint32 reads an uint32 into the supplied buffer.
+// The idea is to make use of the already allocated buffers avoiding additional allocations.
+func (z *ReaderLegacy) readUint32() (uint32, error) {
+ buf := z.buf[:4]
+ _, err := io.ReadFull(z.src, buf)
+ x := binary.LittleEndian.Uint32(buf)
+ return x, err
+}