1 files changed, 200 insertions, 0 deletions
diff --git a/vendor/github.com/pierrec/lz4/v4/internal/lz4stream/frame.go b/vendor/github.com/pierrec/lz4/v4/internal/lz4stream/frame.go
new file mode 100644
index 0000000000..cfbd5674d9
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/v4/internal/lz4stream/frame.go
@@ -0,0 +1,200 @@
+// Package lz4stream provides the types that support reading and writing LZ4 data streams.
+package lz4stream
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+
+	"github.com/pierrec/lz4/v4/internal/lz4block"
+	"github.com/pierrec/lz4/v4/internal/lz4errors"
+	"github.com/pierrec/lz4/v4/internal/xxh32"
+)
+
+//go:generate go run gen.go
+
+const (
+	frameMagic       uint32 = 0x184D2204
+	frameSkipMagic   uint32 = 0x184D2A50
+	frameMagicLegacy uint32 = 0x184C2102
+)
+
+func NewFrame() *Frame {
+	return &Frame{}
+}
+
+type Frame struct {
+	buf        [15]byte // frame descriptor needs at most 4(magic)+4+8+1=11 bytes
+	Magic      uint32
+	Descriptor FrameDescriptor
+	Blocks     Blocks
+	Checksum   uint32
+	checksum   xxh32.XXHZero
+}
+
+// Reset allows reusing the Frame.
+// The Descriptor configuration is not modified.
+func (f *Frame) Reset(num int) {
+	f.Magic = 0
+	f.Descriptor.Checksum = 0
+	f.Descriptor.ContentSize = 0
+	_ = f.Blocks.close(f, num)
+	f.Checksum = 0
+}
+
+func (f *Frame) InitW(dst io.Writer, num int, legacy bool) {
+	if legacy {
+		f.Magic = frameMagicLegacy
+		idx := lz4block.Index(lz4block.Block8Mb)
+		f.Descriptor.Flags.BlockSizeIndexSet(idx)
+	} else {
+		f.Magic = frameMagic
+		f.Descriptor.initW()
+	}
+	f.Blocks.initW(f, dst, num)
+	f.checksum.Reset()
+}
+
+func (f *Frame) CloseW(dst io.Writer, num int) error {
+	if err := f.Blocks.close(f, num); err != nil {
+		return err
+	}
+	if f.isLegacy() {
+		return nil
+	}
+	buf := f.buf[:0]
+	// End mark (data block size of uint32(0)).
+	buf = append(buf, 0, 0, 0, 0)
+	if f.Descriptor.Flags.ContentChecksum() {
+		buf = f.checksum.Sum(buf)
+	}
+	_, err := dst.Write(buf)
+	return err
+}
+
+func (f *Frame) isLegacy() bool {
+	return f.Magic == frameMagicLegacy
+}
+
+func (f *Frame) InitR(src io.Reader, num int) (chan []byte, error) {
+	if f.Magic > 0 {
+		// Header already read.
+		return nil, nil
+	}
+
+newFrame:
+	var err error
+	if f.Magic, err = f.readUint32(src); err != nil {
+		return nil, err
+	}
+	switch m := f.Magic; {
+	case m == frameMagic || m == frameMagicLegacy:
+	// All 16 values of frameSkipMagic are valid.
+	case m>>8 == frameSkipMagic>>8:
+		skip, err := f.readUint32(src)
+		if err != nil {
+			return nil, err
+		}
+		if _, err := io.CopyN(ioutil.Discard, src, int64(skip)); err != nil {
+			return nil, err
+		}
+		goto newFrame
+	default:
+		return nil, lz4errors.ErrInvalidFrame
+	}
+	if err := f.Descriptor.initR(f, src); err != nil {
+		return nil, err
+	}
+	f.checksum.Reset()
+	return f.Blocks.initR(f, num, src)
+}
+
+func (f *Frame) CloseR(src io.Reader) (err error) {
+	if f.isLegacy() {
+		return nil
+	}
+	if !f.Descriptor.Flags.ContentChecksum() {
+		return nil
+	}
+	if f.Checksum, err = f.readUint32(src); err != nil {
+		return err
+	}
+	if c := f.checksum.Sum32(); c != f.Checksum {
+		return fmt.Errorf("%w: got %x; expected %x", lz4errors.ErrInvalidFrameChecksum, c, f.Checksum)
+	}
+	return nil
+}
+
+type FrameDescriptor struct {
+	Flags       DescriptorFlags
+	ContentSize uint64
+	Checksum    uint8
+}
+
+func (fd *FrameDescriptor) initW() {
+	fd.Flags.VersionSet(1)
+	fd.Flags.BlockIndependenceSet(true)
+}
+
+func (fd *FrameDescriptor) Write(f *Frame, dst io.Writer) error {
+	if fd.Checksum > 0 {
+		// Header already written.
+		return nil
+	}
+
+	buf := f.buf[:4]
+	// Write the magic number here even though it belongs to the Frame.
+	binary.LittleEndian.PutUint32(buf, f.Magic)
+	if !f.isLegacy() {
+		buf = buf[:4+2]
+		binary.LittleEndian.PutUint16(buf[4:], uint16(fd.Flags))
+
+		if fd.Flags.Size() {
+			buf = buf[:4+2+8]
+			binary.LittleEndian.PutUint64(buf[4+2:], fd.ContentSize)
+		}
+		fd.Checksum = descriptorChecksum(buf[4:])
+		buf = append(buf, fd.Checksum)
+	}
+
+	_, err := dst.Write(buf)
+	return err
+}
+
+func (fd *FrameDescriptor) initR(f *Frame, src io.Reader) error {
+	if f.isLegacy() {
+		idx := lz4block.Index(lz4block.Block8Mb)
+		f.Descriptor.Flags.BlockSizeIndexSet(idx)
+		return nil
+	}
+	// Read the flags and the checksum, hoping that there is not content size.
+	buf := f.buf[:3]
+	if _, err := io.ReadFull(src, buf); err != nil {
+		return err
+	}
+	descr := binary.LittleEndian.Uint16(buf)
+	fd.Flags = DescriptorFlags(descr)
+	if fd.Flags.Size() {
+		// Append the 8 missing bytes.
+		buf = buf[:3+8]
+		if _, err := io.ReadFull(src, buf[3:]); err != nil {
+			return err
+		}
+		fd.ContentSize = binary.LittleEndian.Uint64(buf[2:])
+	}
+	fd.Checksum = buf[len(buf)-1] // the checksum is the last byte
+	buf = buf[:len(buf)-1]        // all descriptor fields except checksum
+	if c := descriptorChecksum(buf); fd.Checksum != c {
+		return fmt.Errorf("%w: got %x; expected %x", lz4errors.ErrInvalidHeaderChecksum, c, fd.Checksum)
+	}
+	// Validate the elements that can be.
+	if idx := fd.Flags.BlockSizeIndex(); !idx.IsValid() {
+		return lz4errors.ErrOptionInvalidBlockSize
+	}
+	return nil
+}
+
+func descriptorChecksum(buf []byte) byte {
+	return byte(xxh32.ChecksumZero(buf) >> 8)
+}