public CBORObject ReadForFirstByte(int firstbyte)
{
if (this.depth > 500)
{
throw new CBORException("Too deeply nested");
}
if (firstbyte < 0)
{
throw new CBORException("Premature end of data");
}
if (firstbyte == 0xff)
{
throw new CBORException("Unexpected break code encountered");
}
int type = (firstbyte >> 5) & 0x07;
int additional = firstbyte & 0x1f;
long uadditional;
CBORObject fixedObject;
if (this.options.Ctap2Canonical)
{
if (additional >= 0x1c)
{
// NOTE: Includes stop byte and indefinite length data items
throw new CBORException("Invalid canonical CBOR encountered");
}
// Check if this represents a fixed object (NOTE: All fixed objects
// comply with CTAP2 canonical CBOR).
fixedObject = CBORObject.GetFixedObject(firstbyte);
if (fixedObject != null)
{
return(fixedObject);
}
if (type == 6)
{
throw new CBORException("Tags not allowed in canonical CBOR");
}
uadditional = ReadDataLength(
this.stream,
firstbyte,
type,
type == 7);
if (type == 0)
{
return((uadditional >> 63) != 0 ?
CBORObject.FromObject(ToUnsignedEInteger(uadditional)) :
CBORObject.FromObject(uadditional));
}
else if (type == 1)
{
return((uadditional >> 63) != 0 ? CBORObject.FromObject(
ToUnsignedEInteger(uadditional).Add(1).Negate()) :
CBORObject.FromObject((-uadditional) - 1L));
}
else if (type == 7)
{
if (additional < 24)
{
return(CBORObject.FromSimpleValue(additional));
}
else if (additional == 24 && uadditional < 32)
{
throw new CBORException("Invalid simple value encoding");
}
else if (additional == 24)
{
return(CBORObject.FromSimpleValue((int)uadditional));
}
else if (additional == 25)
{
return(CBORObject.FromFloatingPointBits(uadditional, 2));
}
else if (additional == 26)
{
return(CBORObject.FromFloatingPointBits(uadditional, 4));
}
else if (additional == 27)
{
return(CBORObject.FromFloatingPointBits(uadditional, 8));
}
}
else if (type >= 2 && type <= 5)
{
return(this.ReadStringArrayMap(type, uadditional));
}
throw new CBORException("Unexpected data encountered");
}
int expectedLength = CBORObject.GetExpectedLength(firstbyte);
// Data checks
if (expectedLength == -1)
{
// if the head byte is invalid
throw new CBORException("Unexpected data encountered");
}
// Check if this represents a fixed object
fixedObject = CBORObject.GetFixedObject(firstbyte);
if (fixedObject != null)
{
return(fixedObject);
}
// Read fixed-length data
byte[] data = null;
if (expectedLength != 0)
{
data = new byte[expectedLength];
// include the first byte because GetFixedLengthObject
// will assume it exists for some head bytes
data[0] = unchecked ((byte)firstbyte);
if (expectedLength > 1 &&
this.stream.Read(data, 1, expectedLength - 1) != expectedLength
- 1)
{
throw new CBORException("Premature end of data");
}
CBORObject cbor = CBORObject.GetFixedLengthObject(firstbyte, data);
if (this.stringRefs != null && (type == 2 || type == 3))
{
this.stringRefs.AddStringIfNeeded(cbor, expectedLength - 1);
}
return(cbor);
}
if (additional == 31)
{
// Indefinite-length for major types 2 to 5 (other major
// types were already handled in the call to
// GetFixedLengthObject).
switch (type)
{
case 2: {
// Streaming byte string
using (var ms = new MemoryStream()) {
// Requires same type as this one
while (true)
{
int nextByte = this.stream.ReadByte();
if (nextByte == 0xff)
{
// break if the "break" code was read
break;
}
long len = ReadDataLength(this.stream, nextByte, 2);
if ((len >> 63) != 0 || len > Int32.MaxValue)
{
throw new CBORException("Length" + ToUnsignedEInteger(len)
+
" is bigger than supported ");
}
if (nextByte != 0x40)
{
// NOTE: 0x40 means the empty byte string
ReadByteData(this.stream, len, ms);
}
}
if (ms.Position > Int32.MaxValue)
{
throw new
CBORException("Length of bytes to be streamed is bigger" +
"\u0020than supported ");
}
data = ms.ToArray();
return(CBORObject.FromRaw(data));
}
}
case 3: {
// Streaming text string
var builder = new StringBuilder();
while (true)
{
int nextByte = this.stream.ReadByte();
if (nextByte == 0xff)
{
// break if the "break" code was read
break;
}
long len = ReadDataLength(this.stream, nextByte, 3);
if ((len >> 63) != 0 || len > Int32.MaxValue)
{
throw new CBORException("Length" + ToUnsignedEInteger(len) +
" is bigger than supported");
}
if (nextByte != 0x60)
{
// NOTE: 0x60 means the empty string
if (PropertyMap.ExceedsKnownLength(this.stream, len))
{
throw new CBORException("Premature end of data");
}
switch (
DataUtilities.ReadUtf8(
this.stream,
(int)len,
builder,
false))
{
case -1:
throw new CBORException("Invalid UTF-8");
case -2:
throw new CBORException("Premature end of data");
}
}
}
return(CBORObject.FromRaw(builder.ToString()));
}
case 4: {
CBORObject cbor = CBORObject.NewArray();
var vtindex = 0;
// Indefinite-length array
while (true)
{
int headByte = this.stream.ReadByte();
if (headByte < 0)
{
throw new CBORException("Premature end of data");
}
if (headByte == 0xff)
{
// Break code was read
break;
}
++this.depth;
CBORObject o = this.ReadForFirstByte(
headByte);
--this.depth;
cbor.Add(o);
++vtindex;
}
return(cbor);
}
case 5: {
CBORObject cbor = CBORObject.NewMap();
// Indefinite-length map
while (true)
{
int headByte = this.stream.ReadByte();
if (headByte < 0)
{
throw new CBORException("Premature end of data");
}
if (headByte == 0xff)
{
// Break code was read
break;
}
++this.depth;
CBORObject key = this.ReadForFirstByte(headByte);
CBORObject value = this.ReadInternal();
--this.depth;
int oldCount = cbor.Count;
cbor[key] = value;
int newCount = cbor.Count;
if (!this.options.AllowDuplicateKeys && oldCount == newCount)
{
throw new CBORException("Duplicate key already exists");
}
}
return(cbor);
}
default: throw new CBORException("Unexpected data encountered");
}
}
EInteger bigintAdditional = EInteger.Zero;
uadditional = ReadDataLength(this.stream, firstbyte, type);
// The following doesn't check for major types 0 and 1,
// since all of them are fixed-length types and are
// handled in the call to GetFixedLengthObject.
if (type >= 2 && type <= 5)
{
return(this.ReadStringArrayMap(type, uadditional));
}
if (type == 6) // Tagged item
{
var haveFirstByte = false;
var newFirstByte = -1;
if (this.options.ResolveReferences && (uadditional >> 32) == 0)
{
// NOTE: HandleItemTag treats only certain tags up to 256 specially
this.HandleItemTag(uadditional);
}
++this.depth;
CBORObject o = haveFirstByte ? this.ReadForFirstByte(
newFirstByte) : this.ReadInternal();
--this.depth;
if ((uadditional >> 63) != 0)
{
return(CBORObject.FromObjectAndTag(o,
ToUnsignedEInteger(uadditional)));
}
if (uadditional < 65536)
{
if (this.options.ResolveReferences)
{
int uaddl = uadditional >= 257 ? 257 : (uadditional < 0 ? 0 :
(int)uadditional);
switch (uaddl)
{
case 256:
// string tag
this.stringRefs.Pop();
break;
case 25:
// stringref tag
if (o.IsTagged || o.Type != CBORType.Integer)
{
throw new CBORException("stringref must be an unsigned" +
"\u0020integer");
}
return(this.stringRefs.GetString(o.AsEIntegerValue()));
}
}
return(CBORObject.FromObjectAndTag(
o,
(int)uadditional));
}
return(CBORObject.FromObjectAndTag(
o,
(EInteger)uadditional));
}
throw new CBORException("Unexpected data encountered");
}