public override bool TryParse(string epasaText, out EPasa epasa, out EPasaErrorCode errorCode)
{
errorCode = EPasaErrorCode.Success;
epasa = new EPasa();
if (string.IsNullOrEmpty(epasaText))
{
errorCode = EPasaErrorCode.BadFormat;
return(false);
}
var match = _epasaRegex.Match(epasaText);
var checksumDelim = match.Groups["ChecksumDelim"].Success ? match.Groups["ChecksumDelim"].Value : null;
var accountNumber = match.Groups["AccountNumber"].Success ? match.Groups["AccountNumber"].Value : null;
var accountChecksum = match.Groups["Checksum"].Success ? match.Groups["Checksum"].Value : null;
var accountName = match.Groups["AccountName"].Success ? match.Groups["AccountName"].Value : null;
var payloadStartChar = match.Groups["PayloadStartChar"].Success ? match.Groups["PayloadStartChar"].Value : null;
var payloadEndChar = match.Groups["PayloadEndChar"].Success ? match.Groups["PayloadEndChar"].Value : null;
var payloadContent = match.Groups["PayloadContent"].Success ? match.Groups["PayloadContent"].Value : null;
var payloadPasswordDelim = match.Groups["PayloadPasswordDelim"].Success ? match.Groups["PayloadPasswordDelim"].Value : null;
var payloadPassword = match.Groups["PayloadPassword"].Success ? match.Groups["PayloadPassword"].Value : null;
var extendedChecksumDelim = match.Groups["ExtendedChecksumDelim"].Success ? match.Groups["ExtendedChecksumDelim"].Value : null;
var extendedChecksum = match.Groups["ExtendedChecksum"].Success ? match.Groups["ExtendedChecksum"].Value : null;
// Check parsed completely
if (epasaText != match.Value)
{
errorCode = EPasaErrorCode.BadFormat;
return(false);
}
if (accountName != null)
{
// Account Name
if (string.IsNullOrEmpty(accountName))
{
errorCode = EPasaErrorCode.BadFormat;
return(false);
}
epasa.PayloadType = epasa.PayloadType | PayloadType.AddressedByName;
epasa.AccountName = Pascal64Encoding.Unescape(accountName);
epasa.Account = epasa.AccountChecksum = null;
}
else
{
// Account Number
if (!uint.TryParse(accountNumber, out var accNo))
{
errorCode = EPasaErrorCode.InvalidAccountNumber;
return(false);
}
epasa.Account = accNo;
var actualAccountChecksum = AccountHelper.CalculateAccountChecksum(accNo);
if (checksumDelim != null)
{
// validate account checksum
if (!uint.TryParse(accountChecksum, out var accChecksum))
{
errorCode = EPasaErrorCode.AccountChecksumInvalid;
return(false);
}
if (accChecksum != actualAccountChecksum)
{
errorCode = EPasaErrorCode.BadChecksum;
return(false);
}
}
epasa.AccountChecksum = actualAccountChecksum;
}
// Encryption type
switch (payloadStartChar)
{
case null:
break;
case "[":
if (payloadEndChar != "]")
{
errorCode = EPasaErrorCode.MismatchedPayloadEncoding;
return(false);
}
epasa.PayloadType = epasa.PayloadType | PayloadType.Public;
break;
case "(":
if (payloadEndChar != ")")
{
errorCode = EPasaErrorCode.MismatchedPayloadEncoding;
return(false);
}
epasa.PayloadType = epasa.PayloadType | PayloadType.RecipientKeyEncrypted;
break;
case "<":
if (payloadEndChar != ">")
{
errorCode = EPasaErrorCode.MismatchedPayloadEncoding;
return(false);
}
epasa.PayloadType = epasa.PayloadType | PayloadType.SenderKeyEncrypted;
break;
case "{":
if (payloadEndChar != "}")
{
errorCode = EPasaErrorCode.MismatchedPayloadEncoding;
return(false);
}
epasa.PayloadType = epasa.PayloadType | PayloadType.PasswordEncrypted;
break;
default:
throw new NotSupportedException($"Unrecognized start character '{payloadStartChar}'");
}
// Password
if (epasa.PayloadType.HasFlag(PayloadType.PasswordEncrypted))
{
if (payloadPasswordDelim == null)
{
errorCode = EPasaErrorCode.MissingPassword;
return(false);
}
epasa.Password = PascalAsciiEncoding.Unescape(payloadPassword ?? "");
}
else if (payloadPasswordDelim != null)
{
errorCode = EPasaErrorCode.UnusedPassword;
return(false);
}
// Payload
if (payloadStartChar != null)
{
if (payloadContent == null)
{
epasa.Payload = string.Empty;
}
else if (payloadContent.StartsWith("\""))
{
epasa.PayloadType = epasa.PayloadType | PayloadType.AsciiFormatted;
epasa.Payload = PascalAsciiEncoding.Unescape(payloadContent.Trim('"'));
}
else if (payloadContent.StartsWith("0x"))
{
epasa.PayloadType = epasa.PayloadType | PayloadType.HexFormatted;
epasa.Payload = payloadContent.Substring(2);
}
else
{
epasa.PayloadType = epasa.PayloadType | PayloadType.Base58Formatted;
epasa.Payload = payloadContent;
}
}
// Payload Lengths
if (!EPasaHelper.IsValidPayloadLength(epasa.PayloadType, epasa.Payload))
{
errorCode = EPasaErrorCode.PayloadTooLarge;
return(false);
}
// Extended Checksum
var actualChecksum = EPasaHelper.ComputeExtendedChecksum(epasa.ToString(true));
if (extendedChecksumDelim != null)
{
if (extendedChecksum != actualChecksum)
{
errorCode = EPasaErrorCode.BadExtendedChecksum;
return(false);
}
}
epasa.ExtendedChecksum = actualChecksum;
return(true);
}
public string ToString(bool omitExtendedChecksum)
{
var result = string.Empty;
if (PayloadType.HasFlag(PayloadType.AddressedByName))
{
result += Pascal64Encoding.Escape(AccountName);
}
else
{
result += Account.ToString();
if (AccountChecksum != null)
{
result += $"-{AccountChecksum}";
}
}
var payloadContent = string.Empty;
if (PayloadType.HasFlag(PayloadType.AsciiFormatted))
{
payloadContent = $@"""{PascalAsciiEncoding.Escape(Payload)}""";
}
else if (PayloadType.HasFlag(PayloadType.HexFormatted))
{
payloadContent = $@"0x{Payload}";
}
else if (PayloadType.HasFlag(PayloadType.Base58Formatted))
{
payloadContent = $"{Payload}";
}
else
{
// it is non-deterministic, so payload content is ignored
payloadContent = string.Empty;
}
if (PayloadType.HasFlag(PayloadType.Public))
{
result += $"[{payloadContent}]";
}
else if (PayloadType.HasFlag(PayloadType.RecipientKeyEncrypted))
{
result += $"({payloadContent})";
}
else if (PayloadType.HasFlag(PayloadType.SenderKeyEncrypted))
{
result += $"<{payloadContent}>";
}
else if (PayloadType.HasFlag(PayloadType.PasswordEncrypted))
{
result += $"{{{payloadContent}:{PascalAsciiEncoding.Escape(Password)}}}";
}
else
{
// it is non-deterministic, so payload omitted entirely
}
if (ExtendedChecksum != null && !omitExtendedChecksum)
{
result += $":{ExtendedChecksum}";
}
return(result);
}
public static bool IsValidPayloadLength(PayloadType payloadType, string payloadContent)
{
if (string.IsNullOrEmpty(payloadContent))
{
return(true);
}
if (payloadType.HasFlag(PayloadType.Public))
{
if (payloadType.HasFlag(PayloadType.AsciiFormatted))
{
return(PascalAsciiEncoding.Unescape(payloadContent).Length <= MaxPublicAsciiContentLength);
}
if (payloadType.HasFlag(PayloadType.HexFormatted))
{
return(payloadContent.Length <= MaxPublicHexContentLength);
}
if (payloadType.HasFlag(PayloadType.Base58Formatted))
{
return(payloadContent.Length <= MaxPublicBase58ContentLength);
}
// unknown encoding format
return(false);
}
if (payloadType.HasFlag(PayloadType.SenderKeyEncrypted) || payloadType.HasFlag(PayloadType.RecipientKeyEncrypted))
{
if (payloadType.HasFlag(PayloadType.AsciiFormatted))
{
return(PascalAsciiEncoding.Unescape(payloadContent).Length <= MaxECIESAsciiContentLength);
}
if (payloadType.HasFlag(PayloadType.HexFormatted))
{
return(payloadContent.Length <= MaxECIESHexContentLength);
}
if (payloadType.HasFlag(PayloadType.Base58Formatted))
{
return(payloadContent.Length <= MaxECIESBase58ContentLength);
}
// unknown encoding format
return(false);
}
if (payloadType.HasFlag(PayloadType.PasswordEncrypted))
{
if (payloadType.HasFlag(PayloadType.AsciiFormatted))
{
return(PascalAsciiEncoding.Unescape(payloadContent).Length <= MaxAESAsciiContentLength);
}
if (payloadType.HasFlag(PayloadType.HexFormatted))
{
return(payloadContent.Length <= MaxAESHexContentLength);
}
if (payloadType.HasFlag(PayloadType.Base58Formatted))
{
return(payloadContent.Length <= MaxAESBase58ContentLength);
}
// unknown encoding format
return(false);
}
// unknown encryption format
return(false);
}
private EPasaErrorCode TryCompile(EPasaNode epasaNode, EPasa epasa)
{
EPasaErrorCode TryCompileAccount(AccountNode accountNode)
{
switch (accountNode.Type)
{
case TokenType.AccountName:
if (!Pascal64Encoding.IsValidEscaped(accountNode.Name.Value))
{
return(EPasaErrorCode.InvalidAccountName);
}
epasa.AccountName = Pascal64Encoding.Unescape(accountNode.Name.Value);
epasa.PayloadType = epasa.PayloadType.SetFlags(PayloadType.AddressedByName);
break;
case TokenType.AccountNumber:
if (!uint.TryParse(accountNode.AccountNo.Value, out var accNo))
{
return(EPasaErrorCode.BadFormat);
}
if (accountNode.AccountNo.Value.StartsWith("0") && accNo != 0)
{
return(EPasaErrorCode.BadFormat);
}
epasa.Account = accNo;
var actualChecksum = AccountHelper.CalculateAccountChecksum(accNo);
if (accountNode.Checksum != null)
{
if (!uint.TryParse(accountNode.Checksum.Value, out var checksum))
{
return(EPasaErrorCode.BadFormat);
}
if (checksum != actualChecksum)
{
return(EPasaErrorCode.AccountChecksumInvalid);
}
}
epasa.AccountChecksum = actualChecksum;
break;
default:
throw new ArgumentOutOfRangeException(nameof(accountNode));
}
return(EPasaErrorCode.Success);
}
EPasaErrorCode TryCompilePayload(PayloadNode payloadNode)
{
epasa.PayloadType = epasa.PayloadType | payloadNode.Encryption;
if (payloadNode.Content != null)
{
switch (payloadNode.Content.Type)
{
case TokenType.PascalAsciiString:
epasa.PayloadType = epasa.PayloadType | PayloadType.AsciiFormatted;
epasa.Payload = PascalAsciiEncoding.Unescape(payloadNode.Content.Value);
break;
case TokenType.Base58String:
epasa.PayloadType = epasa.PayloadType | PayloadType.Base58Formatted;
epasa.Payload = payloadNode.Content.Value;
break;
case TokenType.HexString:
epasa.PayloadType = epasa.PayloadType | PayloadType.HexFormatted;
epasa.Payload = payloadNode.Content.Value;
break;
default:
throw new ArgumentOutOfRangeException(nameof(payloadNode.Content.Type));
}
if (!EPasaHelper.IsValidPayloadLength(epasa.PayloadType, epasa.Payload))
{
return(EPasaErrorCode.PayloadTooLarge);
}
}
if (payloadNode.Password != null)
{
if (!EPasaHelper.IsValidPasswordLength(payloadNode.Password.Value))
{
return(EPasaErrorCode.InvalidPassword);
}
epasa.Password = PascalAsciiEncoding.Unescape(payloadNode.Password.Value);
}
return(EPasaErrorCode.Success);
}
EPasaErrorCode TryCompileExtendedChecksum(ValueNode extendedChecksumNode)
{
var actualExtendedChecksum = EPasaHelper.ComputeExtendedChecksum(epasa.ToString(true));
if (extendedChecksumNode != null && extendedChecksumNode.Value != actualExtendedChecksum)
{
return(EPasaErrorCode.AccountChecksumInvalid);
}
epasa.ExtendedChecksum = actualExtendedChecksum;
return(EPasaErrorCode.Success);
}
var result = TryCompileAccount(epasaNode.Account);
if (result != EPasaErrorCode.Success)
{
return(result);
}
if (epasaNode.Payload != null)
{
result = TryCompilePayload(epasaNode.Payload);
if (result != EPasaErrorCode.Success)
{
return(result);
}
}
result = TryCompileExtendedChecksum(epasaNode.ExtendedChecksum);
if (result != EPasaErrorCode.Success)
{
return(result);
}
return(result);
}