添加 github.com/pion/dtls 代码

dtls-2.0.9/pkg/protocol/compression_method.go

@@ -0,0 +1,48 @@
+package protocol
+
+// CompressionMethodID is the ID for a CompressionMethod
+type CompressionMethodID byte
+
+const (
+	compressionMethodNull CompressionMethodID = 0
+)
+
+// CompressionMethod represents a TLS Compression Method
+type CompressionMethod struct {
+	ID CompressionMethodID
+}
+
+// CompressionMethods returns all supported CompressionMethods
+func CompressionMethods() map[CompressionMethodID]*CompressionMethod {
+	return map[CompressionMethodID]*CompressionMethod{
+		compressionMethodNull: {ID: compressionMethodNull},
+	}
+}
+
+// DecodeCompressionMethods the given compression methods
+func DecodeCompressionMethods(buf []byte) ([]*CompressionMethod, error) {
+	if len(buf) < 1 {
+		return nil, errBufferTooSmall
+	}
+	compressionMethodsCount := int(buf[0])
+	c := []*CompressionMethod{}
+	for i := 0; i < compressionMethodsCount; i++ {
+		if len(buf) <= i+1 {
+			return nil, errBufferTooSmall
+		}
+		id := CompressionMethodID(buf[i+1])
+		if compressionMethod, ok := CompressionMethods()[id]; ok {
+			c = append(c, compressionMethod)
+		}
+	}
+	return c, nil
+}
+
+// EncodeCompressionMethods the given compression methods
+func EncodeCompressionMethods(c []*CompressionMethod) []byte {
+	out := []byte{byte(len(c))}
+	for i := len(c); i > 0; i-- {
+		out = append(out, byte(c[i-1].ID))
+	}
+	return out
+}