move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/bin/bytes.go

@@ -0,0 +1,54 @@
+package bin
+
+import (
+	"io"
+)
+
+// encodeBytes is same as encodeString, but for bytes.
+func encodeBytes(b, v []byte) []byte {
+	l := len(v)
+	if l <= maxSmallStringLength {
+		b = append(b, byte(l))
+		b = append(b, v...)
+		currentLen := l + 1
+		b = append(b, make([]byte, nearestPaddedValueLength(currentLen)-currentLen)...)
+		return b
+	}
+
+	b = append(b, firstLongStringByte, byte(l), byte(l>>8), byte(l>>16))
+	b = append(b, v...)
+	currentLen := l + 4
+	b = append(b, make([]byte, nearestPaddedValueLength(currentLen)-currentLen)...)
+
+	return b
+}
+
+// decodeBytes is same as decodeString, but for bytes.
+//
+// NB: v is slice of b.
+func decodeBytes(b []byte) (n int, v []byte, err error) {
+	if len(b) == 0 {
+		return 0, nil, io.ErrUnexpectedEOF
+	}
+	if b[0] == firstLongStringByte {
+		if len(b) < 4 {
+			return 0, nil, io.ErrUnexpectedEOF
+		}
+		strLen := uint32(b[1]) | uint32(b[2])<<8 | uint32(b[3])<<16
+		if len(b) < (int(strLen) + 4) {
+			return 0, nil, io.ErrUnexpectedEOF
+		}
+		return nearestPaddedValueLength(int(strLen) + 4), b[4 : strLen+4], nil
+	}
+	strLen := int(b[0])
+	if len(b) < (strLen + 1) {
+		return 0, nil, io.ErrUnexpectedEOF
+	}
+	if strLen > maxSmallStringLength {
+		return 0, nil, &InvalidLengthError{
+			Length: strLen,
+			Where:  "bytes",
+		}
+	}
+	return nearestPaddedValueLength(strLen + 1), b[1 : strLen+1], nil
+}