refactor to mautrix 0.17.x; update deps

vendor/maunium.net/go/mautrix/crypto/goolm/message/decoder.go

@@ -0,0 +1,70 @@
+package message
+
+import (
+	"encoding/binary"
+
+	"maunium.net/go/mautrix/crypto/goolm"
+)
+
+// checkDecodeErr checks if there was an error during decode.
+func checkDecodeErr(readBytes int) error {
+	if readBytes == 0 {
+		//end reached
+		return goolm.ErrInputToSmall
+	}
+	if readBytes < 0 {
+		return goolm.ErrOverflow
+	}
+	return nil
+}
+
+// decodeVarInt decodes a single big-endian encoded varint.
+func decodeVarInt(input []byte) (uint32, int) {
+	value, readBytes := binary.Uvarint(input)
+	return uint32(value), readBytes
+}
+
+// decodeVarString decodes the length of the string (varint) and returns the actual string
+func decodeVarString(input []byte) ([]byte, int) {
+	stringLen, readBytes := decodeVarInt(input)
+	if readBytes <= 0 {
+		return nil, readBytes
+	}
+	input = input[readBytes:]
+	value := input[:stringLen]
+	readBytes += int(stringLen)
+	return value, readBytes
+}
+
+// encodeVarIntByteLength returns the number of bytes needed to encode the uint32.
+func encodeVarIntByteLength(input uint32) int {
+	result := 1
+	for input >= 128 {
+		result++
+		input >>= 7
+	}
+	return result
+}
+
+// encodeVarStringByteLength returns the number of bytes needed to encode the input.
+func encodeVarStringByteLength(input []byte) int {
+	result := encodeVarIntByteLength(uint32(len(input)))
+	result += len(input)
+	return result
+}
+
+// encodeVarInt encodes a single uint32
+func encodeVarInt(input uint32) []byte {
+	out := make([]byte, encodeVarIntByteLength(input))
+	binary.PutUvarint(out, uint64(input))
+	return out
+}
+
+// encodeVarString encodes the length of the input (varint) and appends the actual input
+func encodeVarString(input []byte) []byte {
+	out := make([]byte, encodeVarStringByteLength(input))
+	length := encodeVarInt(uint32(len(input)))
+	copy(out, length)
+	copy(out[len(length):], input)
+	return out
+}