/// <summary>
/// Converts the specified <see cref="string"/>
/// to an equivalent <see cref="Cid"/> object.
/// </summary>
/// <param name="input">
/// The <see cref="Cid.Encode">CID encoded</see> string.
/// </param>
/// <returns>
/// A new <see cref="Cid"/> that is equivalent to <paramref name="input"/>.
/// </returns>
/// <exception cref="FormatException">
/// When the <paramref name="input"/> can not be decoded.
/// </exception>
/// <seealso cref="Encode"/>
public static Cid Decode(string input)
{
try
{
// SHA2-256 MultiHash is CID v0.
if (input.Length == 46 && input.StartsWith("Qm"))
{
return((Cid) new MultiHash(input));
}
using (var ms = new MemoryStream(MultiBase.Decode(input), false))
{
var version = ms.ReadVarint32();
if (version != 1)
{
throw new InvalidDataException($"Unknown CID version '{version}'.");
}
return(new Cid
{
Version = version,
Encoding = Registry.MultiBaseAlgorithm.Codes[input[0]].Name,
ContentType = ms.ReadMultiCodec().Name,
Hash = new MultiHash(ms)
});
}
}
catch (Exception e)
{
throw new FormatException($"Invalid CID '{input}'.", e);
}
}
/// <summary>
/// Returns a string representation of the CID
/// according to the provided format specifier.
/// </summary>
/// <param name="format">
/// A single format specifier that indicates how to format the value of the
/// CID. Can be "G" or "L".
/// </param>
/// <returns>
/// The CID in the specified <paramref name="format"/>.
/// </returns>
/// <exception cref="FormatException">
/// <paramref name="format"/> is not valid.
/// </exception>
/// <remarks>
/// <para>
/// The "G" format specifier is the same as calling <see cref="Encode"/>.
/// </para>
/// <list type="table">
/// <listheader>
/// <term>Specifier</term>
/// <description>return value</description>
/// </listheader>
/// <item>
/// <term>G</term>
/// <description>QmXg9Pp2ytZ14xgmQjYEiHjVjMFXzCVVEcRTWJBmLgR39V</description>
/// </item>
/// <item>
/// <term>L</term>
/// <description>base58btc cidv0 dag-pb sha2-256 Qm...</description>
/// </item>
/// </list>
/// </remarks>
public string ToString(string format)
{
switch (format)
{
case "G":
return(Encode());
case "L":
var sb = new StringBuilder();
sb.Append(Encoding);
sb.Append(' ');
sb.Append("cidv");
sb.Append(Version);
sb.Append(' ');
sb.Append(ContentType);
if (Hash != null)
{
sb.Append(' ');
sb.Append(Hash.Algorithm.Name);
sb.Append(' ');
sb.Append(MultiBase.Encode(Hash.ToArray(), Encoding).Substring(1));
}
return(sb.ToString());
default:
throw new FormatException($"Invalid CID format specifier '{format}'.");
}
}
public void Invalid_Encoded_String()
{
foreach (var alg in MultiBaseAlgorithm.All)
{
var bad = alg.Code + "?";
ExceptionAssert.Throws <FormatException>(() => MultiBase.Decode(bad));
}
}
public void Codec()
{
var bytes = new byte[] { 1, 2, 3, 4, 5 };
var bytes1 = MultiBase.Decode(MultiBase.Encode(bytes));
var bytes2 = MultiBase.Decode(MultiBase.Encode(bytes, "base16"));
CollectionAssert.AreEqual(bytes, bytes1);
CollectionAssert.AreEqual(bytes, bytes2);
}
public void EmptyData()
{
var empty = new byte[0];
foreach (var alg in MultiBaseAlgorithm.All)
{
var s = MultiBase.Encode(empty, alg.Name);
CollectionAssert.AreEqual(empty, MultiBase.Decode(s), alg.Name);
}
}
public void CheckMultiBase()
{
foreach (var v in TestVectors)
{
var bytes = Encoding.UTF8.GetBytes(v.Input);
var s = MultiBase.Encode(bytes, v.Algorithm);
Assert.AreEqual(v.Output, s);
CollectionAssert.AreEqual(bytes, MultiBase.Decode(s));
}
}
public void Decode_Bad_Formats()
{
ExceptionAssert.Throws <ArgumentNullException>(() => MultiBase.Decode(null));
ExceptionAssert.Throws <ArgumentNullException>(() => MultiBase.Decode(""));
ExceptionAssert.Throws <ArgumentNullException>(() => MultiBase.Decode(" "));
ExceptionAssert.Throws <FormatException>(() => MultiBase.Decode("?"));
ExceptionAssert.Throws <FormatException>(() => MultiBase.Decode("??"));
ExceptionAssert.Throws <FormatException>(() => MultiBase.Decode("???"));
ExceptionAssert.Throws <FormatException>(() => MultiBase.Decode("fXX"));
}
/// <summary>
/// Converts the CID to its equivalent string representation.
/// </summary>
/// <returns>
/// The string representation of the <see cref="Cid"/>.
/// </returns>
/// <remarks>
/// For <see cref="Version"/> 0, this is equalivalent to the
/// <see cref="MultiHash.ToBase58()">base58btc encoding</see>
/// of the <see cref="Hash"/>.
/// </remarks>
/// <seealso cref="Decode"/>
public string Encode()
{
if (Version == 0)
{
return(Hash.ToBase58());
}
using (var ms = new MemoryStream())
{
ms.WriteVarint(Version);
ms.WriteMultiCodec(ContentType);
Hash.Write(ms);
return(MultiBase.Encode(ms.ToArray(), Encoding));
}
}
/// <summary>
/// A CID that is readable by a human.
/// </summary>
/// <returns>
/// e.g. "base58btc cidv0 dag-pb sha2-256 Qm..."
/// </returns>
public override string ToString()
{
var sb = new StringBuilder();
sb.Append(Encoding);
sb.Append(' ');
sb.Append("cidv");
sb.Append(Version);
sb.Append(' ');
sb.Append(ContentType);
if (Hash != null)
{
sb.Append(' ');
sb.Append(Hash.Algorithm.Name);
sb.Append(' ');
sb.Append(MultiBase.Encode(Hash.ToArray(), Encoding).Substring(1));
}
return sb.ToString();
}
/// <summary>
/// Converts the CID to its equivalent string representation.
/// </summary>
/// <returns>
/// The string representation of the <see cref="Cid"/>.
/// </returns>
/// <remarks>
/// For <see cref="Version"/> 0, this is equalivalent to the
/// <see cref="MultiHash.ToBase58()">base58btc encoding</see>
/// of the <see cref="Hash"/>.
/// </remarks>
/// <seealso cref="Decode"/>
public string Encode()
{
if (encodedValue != null)
return encodedValue;
if (Version == 0)
{
encodedValue = Hash.ToBase58();
}
else
{
using (var ms = new MemoryStream())
{
ms.WriteVarint(Version);
ms.WriteMultiCodec(ContentType);
Hash.Write(ms);
encodedValue = MultiBase.Encode(ms.ToArray(), Encoding);
}
}
return encodedValue;
}
public void Encode_Null_Data_Not_Allowed()
{
ExceptionAssert.Throws <ArgumentNullException>(() => MultiBase.Encode(null));
}
public void Encode_Unknown_Algorithm()
{
var bytes = new byte[] { 1, 2, 3, 4, 5 };
ExceptionAssert.Throws <KeyNotFoundException>(() => MultiBase.Encode(bytes, "unknown"));
}
