Add 'lib/protocol/' from commit 'f91191218b192ace841c878f161832d19c09145a'

git-subtree-dir: lib/protocol
git-subtree-mainline: 5ecb8bdd8a
git-subtree-split: f91191218b

lib/protocol/compression.go

@@ -0,0 +1,53 @@
+// Copyright (C) 2015 The Protocol Authors.
+
+package protocol
+
+import "fmt"
+
+type Compression int
+
+const (
+	CompressMetadata Compression = iota // zero value is the default, default should be "metadata"
+	CompressNever
+	CompressAlways
+
+	compressionThreshold = 128 // don't bother compressing messages smaller than this many bytes
+)
+
+var compressionMarshal = map[Compression]string{
+	CompressNever:    "never",
+	CompressMetadata: "metadata",
+	CompressAlways:   "always",
+}
+
+var compressionUnmarshal = map[string]Compression{
+	// Legacy
+	"false": CompressNever,
+	"true":  CompressMetadata,
+
+	// Current
+	"never":    CompressNever,
+	"metadata": CompressMetadata,
+	"always":   CompressAlways,
+}
+
+func (c Compression) String() string {
+	s, ok := compressionMarshal[c]
+	if !ok {
+		return fmt.Sprintf("unknown:%d", c)
+	}
+	return s
+}
+
+func (c Compression) GoString() string {
+	return fmt.Sprintf("%q", c.String())
+}
+
+func (c Compression) MarshalText() ([]byte, error) {
+	return []byte(compressionMarshal[c]), nil
+}
+
+func (c *Compression) UnmarshalText(bs []byte) error {
+	*c = compressionUnmarshal[string(bs)]
+	return nil
+}