[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/klauspost/compress/zstd/decodeheader.go b/vendor/github.com/klauspost/compress/zstd/decodeheader.go
new file mode 100644
index 0000000..69736e8
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/decodeheader.go
@@ -0,0 +1,202 @@
+// Copyright 2020+ Klaus Post. All rights reserved.
+// License information can be found in the LICENSE file.
+
+package zstd
+
+import (
+ "bytes"
+ "errors"
+ "io"
+)
+
+// HeaderMaxSize is the maximum size of a Frame and Block Header.
+// If less is sent to Header.Decode it *may* still contain enough information.
+const HeaderMaxSize = 14 + 3
+
+// Header contains information about the first frame and block within that.
+type Header struct {
+ // Window Size the window of data to keep while decoding.
+ // Will only be set if HasFCS is false.
+ WindowSize uint64
+
+ // Frame content size.
+ // Expected size of the entire frame.
+ FrameContentSize uint64
+
+ // Dictionary ID.
+ // If 0, no dictionary.
+ DictionaryID uint32
+
+ // First block information.
+ FirstBlock struct {
+ // OK will be set if first block could be decoded.
+ OK bool
+
+ // Is this the last block of a frame?
+ Last bool
+
+ // Is the data compressed?
+ // If true CompressedSize will be populated.
+ // Unfortunately DecompressedSize cannot be determined
+ // without decoding the blocks.
+ Compressed bool
+
+ // DecompressedSize is the expected decompressed size of the block.
+ // Will be 0 if it cannot be determined.
+ DecompressedSize int
+
+ // CompressedSize of the data in the block.
+ // Does not include the block header.
+ // Will be equal to DecompressedSize if not Compressed.
+ CompressedSize int
+ }
+
+ // Skippable will be true if the frame is meant to be skipped.
+ // No other information will be populated.
+ Skippable bool
+
+ // If set there is a checksum present for the block content.
+ HasCheckSum bool
+
+ // If this is true FrameContentSize will have a valid value
+ HasFCS bool
+
+ SingleSegment bool
+}
+
+// Decode the header from the beginning of the stream.
+// This will decode the frame header and the first block header if enough bytes are provided.
+// It is recommended to provide at least HeaderMaxSize bytes.
+// If the frame header cannot be read an error will be returned.
+// If there isn't enough input, io.ErrUnexpectedEOF is returned.
+// The FirstBlock.OK will indicate if enough information was available to decode the first block header.
+func (h *Header) Decode(in []byte) error {
+ if len(in) < 4 {
+ return io.ErrUnexpectedEOF
+ }
+ b, in := in[:4], in[4:]
+ if !bytes.Equal(b, frameMagic) {
+ if !bytes.Equal(b[1:4], skippableFrameMagic) || b[0]&0xf0 != 0x50 {
+ return ErrMagicMismatch
+ }
+ *h = Header{Skippable: true}
+ return nil
+ }
+ if len(in) < 1 {
+ return io.ErrUnexpectedEOF
+ }
+
+ // Clear output
+ *h = Header{}
+ fhd, in := in[0], in[1:]
+ h.SingleSegment = fhd&(1<<5) != 0
+ h.HasCheckSum = fhd&(1<<2) != 0
+
+ if fhd&(1<<3) != 0 {
+ return errors.New("reserved bit set on frame header")
+ }
+
+ // Read Window_Descriptor
+ // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#window_descriptor
+ if !h.SingleSegment {
+ if len(in) < 1 {
+ return io.ErrUnexpectedEOF
+ }
+ var wd byte
+ wd, in = in[0], in[1:]
+ windowLog := 10 + (wd >> 3)
+ windowBase := uint64(1) << windowLog
+ windowAdd := (windowBase / 8) * uint64(wd&0x7)
+ h.WindowSize = windowBase + windowAdd
+ }
+
+ // Read Dictionary_ID
+ // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#dictionary_id
+ if size := fhd & 3; size != 0 {
+ if size == 3 {
+ size = 4
+ }
+ if len(in) < int(size) {
+ return io.ErrUnexpectedEOF
+ }
+ b, in = in[:size], in[size:]
+ if b == nil {
+ return io.ErrUnexpectedEOF
+ }
+ switch size {
+ case 1:
+ h.DictionaryID = uint32(b[0])
+ case 2:
+ h.DictionaryID = uint32(b[0]) | (uint32(b[1]) << 8)
+ case 4:
+ h.DictionaryID = uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24)
+ }
+ }
+
+ // Read Frame_Content_Size
+ // https://github.com/facebook/zstd/blob/dev/doc/zstd_compression_format.md#frame_content_size
+ var fcsSize int
+ v := fhd >> 6
+ switch v {
+ case 0:
+ if h.SingleSegment {
+ fcsSize = 1
+ }
+ default:
+ fcsSize = 1 << v
+ }
+
+ if fcsSize > 0 {
+ h.HasFCS = true
+ if len(in) < fcsSize {
+ return io.ErrUnexpectedEOF
+ }
+ b, in = in[:fcsSize], in[fcsSize:]
+ if b == nil {
+ return io.ErrUnexpectedEOF
+ }
+ switch fcsSize {
+ case 1:
+ h.FrameContentSize = uint64(b[0])
+ case 2:
+ // When FCS_Field_Size is 2, the offset of 256 is added.
+ h.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) + 256
+ case 4:
+ h.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) | (uint64(b[2]) << 16) | (uint64(b[3]) << 24)
+ case 8:
+ d1 := uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24)
+ d2 := uint32(b[4]) | (uint32(b[5]) << 8) | (uint32(b[6]) << 16) | (uint32(b[7]) << 24)
+ h.FrameContentSize = uint64(d1) | (uint64(d2) << 32)
+ }
+ }
+
+ // Frame Header done, we will not fail from now on.
+ if len(in) < 3 {
+ return nil
+ }
+ tmp := in[:3]
+ bh := uint32(tmp[0]) | (uint32(tmp[1]) << 8) | (uint32(tmp[2]) << 16)
+ h.FirstBlock.Last = bh&1 != 0
+ blockType := blockType((bh >> 1) & 3)
+ // find size.
+ cSize := int(bh >> 3)
+ switch blockType {
+ case blockTypeReserved:
+ return nil
+ case blockTypeRLE:
+ h.FirstBlock.Compressed = true
+ h.FirstBlock.DecompressedSize = cSize
+ h.FirstBlock.CompressedSize = 1
+ case blockTypeCompressed:
+ h.FirstBlock.Compressed = true
+ h.FirstBlock.CompressedSize = cSize
+ case blockTypeRaw:
+ h.FirstBlock.DecompressedSize = cSize
+ h.FirstBlock.CompressedSize = cSize
+ default:
+ panic("Invalid block type")
+ }
+
+ h.FirstBlock.OK = true
+ return nil
+}