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AspClassic.Scripting/SourceSpan.cs

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+using System;
+using System.Globalization;
+
+namespace AspClassic.Scripting;
+
+[Serializable]
+public struct SourceSpan
+{
+	private readonly SourceLocation _start;
+
+	private readonly SourceLocation _end;
+
+	public static readonly SourceSpan None = new SourceSpan(SourceLocation.None, SourceLocation.None);
+
+	public static readonly SourceSpan Invalid = new SourceSpan(SourceLocation.Invalid, SourceLocation.Invalid);
+
+	public SourceLocation Start => _start;
+
+	public SourceLocation End => _end;
+
+	public int Length => _end.Index - _start.Index;
+
+	public bool IsValid
+	{
+		get
+		{
+			if (_start.IsValid)
+			{
+				return _end.IsValid;
+			}
+			return false;
+		}
+	}
+
+	public SourceSpan(SourceLocation start, SourceLocation end)
+	{
+		ValidateLocations(start, end);
+		_start = start;
+		_end = end;
+	}
+
+	private static void ValidateLocations(SourceLocation start, SourceLocation end)
+	{
+		if (start.IsValid && end.IsValid)
+		{
+			if (start > end)
+			{
+				throw new ArgumentException("Start and End must be well ordered");
+			}
+		}
+		else if (start.IsValid || end.IsValid)
+		{
+			throw new ArgumentException("Start and End must both be valid or both invalid");
+		}
+	}
+
+	public static bool operator ==(SourceSpan left, SourceSpan right)
+	{
+		if (left._start == right._start)
+		{
+			return left._end == right._end;
+		}
+		return false;
+	}
+
+	public static bool operator !=(SourceSpan left, SourceSpan right)
+	{
+		if (!(left._start != right._start))
+		{
+			return left._end != right._end;
+		}
+		return true;
+	}
+
+	public override bool Equals(object obj)
+	{
+		if (!(obj is SourceSpan sourceSpan))
+		{
+			return false;
+		}
+		if (_start == sourceSpan._start)
+		{
+			return _end == sourceSpan._end;
+		}
+		return false;
+	}
+
+	public override string ToString()
+	{
+		SourceLocation start = _start;
+		string text = start.ToString();
+		SourceLocation end = _end;
+		return text + " - " + end.ToString();
+	}
+
+	public override int GetHashCode()
+	{
+		return _start.Column ^ (_end.Column << 7) ^ (_start.Line << 14) ^ (_end.Line << 23);
+	}
+
+	internal string ToDebugString()
+	{
+		return string.Format(CultureInfo.CurrentCulture, "{0}-{1}", new object[2]
+		{
+			_start.ToDebugString(),
+			_end.ToDebugString()
+		});
+	}
+}