/// <summary>
/// Parses a <see cref="ulong"/> from the specified <see cref="ReadOnlyBuffer"/>
/// </summary>
/// <param name="buffer">The <see cref="ReadOnlyBuffer"/> to parse</param>
public static ulong GetUInt64(this ReadOnlyBuffer buffer)
{
if (Utf8Parser.TryParse(buffer.First.Span, out ulong value, out _))
{
return(value);
}
if (buffer.IsSingleSegment) // no more data to parse
{
throw new InvalidOperationException();
}
var bufferLength = buffer.Length;
int toParseLength = 21; // longest invariant UTF8 UInt64 + 1 (so we know there is a delimiter at teh end)
if (bufferLength < 21)
{
toParseLength = (int)bufferLength;
}
Span <byte> toParseBuffer = stackalloc byte[toParseLength];
buffer.CopyTo(toParseBuffer);
if (Utf8Parser.TryParse(toParseBuffer, out value, out _))
{
return(value);
}
throw new InvalidOperationException();
}
/// <summary>
/// Decodes the utf8 encoded bytes in the <see cref="ReadOnlyBuffer"/> into a <see cref="string"/>
/// </summary>
/// <param name="buffer">The buffer to decode</param>
public static string GetUtf8Span(this ReadOnlyBuffer buffer)
{
if (buffer.IsEmpty)
{
return(null);
}
// Assign 'textSpan' to something formally stack-referring.
// The default classification is "returnable, not referring to stack", we want the opposite in this case.
ReadOnlySpan <byte> textSpan = stackalloc byte[0];
if (buffer.IsSingleSegment)
{
textSpan = buffer.First.Span;
}
else if (buffer.Length < 128) // REVIEW: What's a good number
{
Span <byte> destination = stackalloc byte[128];
buffer.CopyTo(destination);
// We are able to cast because buffer.Length < 128
textSpan = destination.Slice(0, (int)buffer.Length);
}
else
{
// Heap allocated copy to parse into array (should be rare)
textSpan = new ReadOnlySpan <byte>(buffer.ToArray());
}
return(new Utf8Span(textSpan).ToString());
}
public static void CopyToSpan()
{
int[] src = { 1, 2, 3 };
int[] dst = { 99, 100, 101 };
var srcBuffer = new ReadOnlyBuffer <int>(src);
srcBuffer.CopyTo(dst.AsSpan());
Assert.Equal <int>(src, dst);
}
public void Allocate_ReadBackBuffer_Copy_Range(Device device, int destinationOffset, int bufferOffset, int count)
{
int[] source = new int[4096];
new Random(42).NextBytes(source.AsSpan().AsBytes());
using ReadOnlyBuffer <int> readOnlyBuffer = device.Get().AllocateReadOnlyBuffer(source);
using ReadBackBuffer <int> readBackBuffer = device.Get().AllocateReadBackBuffer <int>(readOnlyBuffer.Length);
readOnlyBuffer.CopyTo(readBackBuffer, destinationOffset, bufferOffset, count);
Assert.AreEqual(source.Length, readBackBuffer.Length);
Assert.IsTrue(source.AsSpan(bufferOffset, count).SequenceEqual(readBackBuffer.Span.Slice(destinationOffset, count)));
}
public void Allocate_ReadBackBuffer_Copy_Full(Device device)
{
int[] source = new int[4096];
new Random(42).NextBytes(source.AsSpan().AsBytes());
using ReadOnlyBuffer <int> readOnlyBuffer = device.Get().AllocateReadOnlyBuffer(source);
using ReadBackBuffer <int> readBackBuffer = device.Get().AllocateReadBackBuffer <int>(readOnlyBuffer.Length);
readOnlyBuffer.CopyTo(readBackBuffer);
Assert.AreEqual(source.Length, readBackBuffer.Length);
Assert.IsTrue(source.AsSpan().SequenceEqual(readBackBuffer.Span));
}