wehub-resource-sync
83 lines
3.0 KiB
C#
83 lines
3.0 KiB
C#
using System.Runtime.CompilerServices;
|
|
|
|
namespace T3.Editor.Gui.Styling;
|
|
|
|
/// <summary>
|
|
/// Supports helper for allocation free string interpolation.
|
|
///
|
|
/// For rendering flexible string content with ImGui generating new string causes a lot of GC
|
|
/// allocations. This class provides some helpers to optimized the most common usecases.
|
|
/// </summary>
|
|
public static class SpanFormat
|
|
{
|
|
|
|
|
|
/// <summary>
|
|
/// Formats an interpolated string directly into a stack-allocated buffer to avoid heap allocations.
|
|
/// </summary>
|
|
/// <param name="buffer">The destination span, typically created via <see langword="stackalloc"/>.</param>
|
|
/// <param name="handler">An internal handler that performs the zero-allocation formatting logic.</param>
|
|
/// <returns>A view into the portion of the buffer containing the formatted characters.</returns>
|
|
/// <remarks>
|
|
/// This is intended for high-performance UI loops where generating temporary strings would cause GC pressure.
|
|
/// </remarks>
|
|
/// <example>
|
|
/// <code>
|
|
/// Span<char> buffer = stackalloc char[32];
|
|
/// var label = buffer.Format($"{count} Items##{id}\0");
|
|
/// ImGui.TextUnformatted(label);
|
|
/// </code>
|
|
/// </example>
|
|
public static ReadOnlySpan<char> Format(this Span<char> buffer,
|
|
[InterpolatedStringHandlerArgument("buffer")]
|
|
TryWriteHandler handler)
|
|
{
|
|
return buffer[..handler.CharsWritten];
|
|
}
|
|
|
|
// This simple handler tells the compiler how to use TryWrite under the hood
|
|
[InterpolatedStringHandler]
|
|
public ref struct TryWriteHandler
|
|
{
|
|
private readonly Span<char> _destination;
|
|
public int CharsWritten { get; private set; }
|
|
|
|
public TryWriteHandler(int literalLength, int holeCount, Span<char> destination)
|
|
{
|
|
_destination = destination;
|
|
CharsWritten = 0;
|
|
}
|
|
|
|
public bool AppendLiteral(string value)
|
|
{
|
|
if (value.AsSpan().TryCopyTo(_destination[CharsWritten..]))
|
|
{
|
|
CharsWritten += value.Length;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
public bool AppendFormatted<T>(T value)
|
|
{
|
|
// Optimized path for numbers and other formattable types
|
|
if (value is ISpanFormattable formattable)
|
|
{
|
|
if (formattable.TryFormat(_destination[CharsWritten..], out int written, default, default))
|
|
{
|
|
CharsWritten += written;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Fallback for strings or other types
|
|
var s = value?.ToString();
|
|
if (s != null && s.AsSpan().TryCopyTo(_destination[CharsWritten..]))
|
|
{
|
|
CharsWritten += s.Length;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
} |