Initial QSfera import

Server/vendor/github.com/segmentio/kafka-go/compress/compress.go

@@ -0,0 +1,124 @@
+package compress
+
+import (
+	"encoding"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/segmentio/kafka-go/compress/gzip"
+	"github.com/segmentio/kafka-go/compress/lz4"
+	"github.com/segmentio/kafka-go/compress/snappy"
+	"github.com/segmentio/kafka-go/compress/zstd"
+)
+
+// Compression represents the compression applied to a record set.
+type Compression int8
+
+const (
+	None   Compression = 0
+	Gzip   Compression = 1
+	Snappy Compression = 2
+	Lz4    Compression = 3
+	Zstd   Compression = 4
+)
+
+func (c Compression) Codec() Codec {
+	if i := int(c); i >= 0 && i < len(Codecs) {
+		return Codecs[i]
+	}
+	return nil
+}
+
+func (c Compression) String() string {
+	if codec := c.Codec(); codec != nil {
+		return codec.Name()
+	}
+	return "uncompressed"
+}
+
+func (c Compression) MarshalText() ([]byte, error) {
+	return []byte(c.String()), nil
+}
+
+func (c *Compression) UnmarshalText(b []byte) error {
+	switch string(b) {
+	case "none", "uncompressed":
+		*c = None
+		return nil
+	}
+
+	for _, codec := range Codecs[None+1:] {
+		if codec.Name() == string(b) {
+			*c = Compression(codec.Code())
+			return nil
+		}
+	}
+
+	i, err := strconv.ParseInt(string(b), 10, 64)
+	if err == nil && i >= 0 && i < int64(len(Codecs)) {
+		*c = Compression(i)
+		return nil
+	}
+
+	s := &strings.Builder{}
+	s.WriteString("none, uncompressed")
+
+	for i, codec := range Codecs[None+1:] {
+		if i < (len(Codecs) - 1) {
+			s.WriteString(", ")
+		} else {
+			s.WriteString(", or ")
+		}
+		s.WriteString(codec.Name())
+	}
+
+	return fmt.Errorf("compression format must be one of %s, not %q", s, b)
+}
+
+var (
+	_ encoding.TextMarshaler   = Compression(0)
+	_ encoding.TextUnmarshaler = (*Compression)(nil)
+)
+
+// Codec represents a compression codec to encode and decode the messages.
+// See : https://cwiki.apache.org/confluence/display/KAFKA/Compression
+//
+// A Codec must be safe for concurrent access by multiple go routines.
+type Codec interface {
+	// Code returns the compression codec code
+	Code() int8
+
+	// Human-readable name for the codec.
+	Name() string
+
+	// Constructs a new reader which decompresses data from r.
+	NewReader(r io.Reader) io.ReadCloser
+
+	// Constructs a new writer which writes compressed data to w.
+	NewWriter(w io.Writer) io.WriteCloser
+}
+
+var (
+	// The global gzip codec installed on the Codecs table.
+	GzipCodec gzip.Codec
+
+	// The global snappy codec installed on the Codecs table.
+	SnappyCodec snappy.Codec
+
+	// The global lz4 codec installed on the Codecs table.
+	Lz4Codec lz4.Codec
+
+	// The global zstd codec installed on the Codecs table.
+	ZstdCodec zstd.Codec
+
+	// The global table of compression codecs supported by the kafka protocol.
+	Codecs = [...]Codec{
+		None:   nil,
+		Gzip:   &GzipCodec,
+		Snappy: &SnappyCodec,
+		Lz4:    &Lz4Codec,
+		Zstd:   &ZstdCodec,
+	}
+)