static BEncodedString DecodeString(Stream reader, int length)
{
int read;
while ((read = reader.ReadByte()) != -1)
{
if (read == ':')
{
var bytes = new byte[length];
if (reader.Read(bytes, 0, length) != length)
{
throw new BEncodingException("Couldn't decode string");
}
return(BEncodedString.FromMemory(new ReadOnlyMemory <byte> (bytes)));
}
if (read < '0' || read > '9')
{
throw new BEncodingException($"Invalid BEncodedString. Length was '{length}' instead of a number");
}
length = length * 10 + (read - '0');
}
throw new BEncodingException("Invalid data found. Aborting");
}
static BEncodedString DecodeString(ref ReadOnlySpan <byte> buffer)
{
int length = 0;
for (int i = 0; i < buffer.Length; i++)
{
if (buffer[i] == (byte)':')
{
// Consume the ':' character
i++;
// Ensure we have enough bytes left
if (buffer.Length < (i + length))
{
throw new BEncodingException($"Invalid BEncodedString. The buffer does not contain at least {length} bytes.");
}
// Copy the data out!
var bytes = new byte[length];
buffer.Slice(i, length).CopyTo(bytes);
buffer = buffer.Slice(i + length);
return(BEncodedString.FromMemory(bytes));
}
if (buffer[i] < (byte)'0' || buffer[i] > (byte)'9')
{
throw new BEncodingException($"Invalid BEncodedString. Length was '{length}' instead of a number");
}
length = length * 10 + (buffer[i] - '0');
}
throw new BEncodingException($"Invalid BEncodedString. The ':' separater was not found.");
}
public void EmptyStringTests()
{
var variants = new[] {
new BEncodedString(Array.Empty <byte> ()),
new BEncodedString(Array.Empty <char> ()),
new BEncodedString(""),
BEncodedString.FromMemory(null),
BEncodedString.FromMemory(Memory <byte> .Empty),
};
foreach (var variant in variants)
{
Assert.IsTrue(BEncodedString.IsNullOrEmpty(variant));
Assert.AreEqual(2, variant.LengthInBytes());
Assert.AreEqual("", variant.Text);
Assert.AreEqual(0, variant.Span.Length);
}
}
