private static bool TryReadStringImpl(ReadOnlySequence <byte> sequence, out string value, ref int readSize, Decoder decoder)
{
value = ReadStringImpl(sequence, decoder);
readSize += sequence.GetIntLength();
return(true);
}
private static string ReadStringImpl(ReadOnlySequence <byte> sequence, Decoder decoder)
{
if (sequence.IsSingleSegment)
{
return(ReadStringImpl(sequence.First.Span, decoder));
}
var safeDecoder = decoder.GetThreadStatic();
using (var rentedBuffer = MemoryPool <char> .Shared.Rent(sequence.GetIntLength()))
{
var chars = rentedBuffer.Memory.Span;
var length = 0;
var leftOver = ReadOnlySpan <byte> .Empty;
foreach (var memory in sequence)
{
if (memory.IsEmpty)
{
continue;
}
var bytes = memory.Span;
using (var rentedBytes = GetMemoryOwner(leftOver, bytes))
{
safeDecoder.Convert(
rentedBytes != null ? rentedBytes.Memory.Span : bytes,
chars,
false,
out var bytesUsed,
out var charsUsed,
out var completed);
chars = chars.Slice(charsUsed);
length += charsUsed;
leftOver = completed ? ReadOnlySpan <byte> .Empty : bytes.Slice(bytesUsed - leftOver.Length);
}
}
if (!leftOver.IsEmpty)
{
throw GetInvalidStringException();
}
return(rentedBuffer.Memory.Span.Slice(0, length).ToString());
}
IMemoryOwner <byte> GetMemoryOwner(ReadOnlySpan <byte> leftOver, ReadOnlySpan <byte> bytes)
{
if (leftOver.IsEmpty)
{
return(null);
}
var owner = FixedLengthMemoryPool <byte> .Shared.Rent(leftOver.Length + bytes.Length);
var span = owner.Memory.Span;
leftOver.CopyTo(span);
bytes.CopyTo(span.Slice(leftOver.Length));
return(owner);
}
}