Add Fs.Range

src/LibHac/Fs/Common/Range.cs

@@ -0,0 +1,66 @@
+// ReSharper disable InconsistentNaming CheckNamespace
+
+using System;
+using LibHac.Diag;
+
+namespace LibHac.Fs;
+
+/// <summary>
+/// Represents a contiguous range of offsets in a piece of data.
+/// </summary>
+/// <remarks>Based on FS 13.1.0 (nnSdk 13.4.0)</remarks>
+public readonly struct Range : IEquatable<Range>, IComparable<Range>
+{
+    public readonly long Offset;
+    public readonly long Size;
+
+    public Range(long offset, long size)
+    {
+        Offset = offset;
+        Size = size;
+    }
+
+    public bool Contains(Range range)
+    {
+        return Offset <= range.Offset &&
+               range.Offset + range.Size <= Offset + Size;
+    }
+
+    public bool HasIntersection(Range range)
+    {
+        return Offset + Size > range.Offset &&
+               range.Offset + range.Size > Offset;
+    }
+
+    public bool IsAdjacent(Range range)
+    {
+        return Offset + Size == range.Offset ||
+               range.Offset + range.Size == Offset;
+    }
+
+    public Range MakeMerge(Range range)
+    {
+        Assert.SdkAssert(HasIntersection(range) || IsAdjacent(range));
+
+        long endOffsetThis = Offset + Size;
+        long endOffsetOther = range.Offset + range.Size;
+
+        long startOffsetMerged = Math.Min(Offset, range.Offset);
+        long endOffsetMerged = Math.Max(endOffsetThis, endOffsetOther);
+
+        return new Range(startOffsetMerged, endOffsetMerged - startOffsetMerged);
+    }
+
+    // Equality is done with only the offset because this type is mainly used with RangeSet
+    // which will never contain multiple ranges with the same offset.
+    public static bool operator <(Range lhs, Range rhs) => lhs.Offset < rhs.Offset;
+    public static bool operator >(Range lhs, Range rhs) => lhs.Offset > rhs.Offset;
+    public static bool operator ==(Range lhs, Range rhs) => lhs.Offset == rhs.Offset;
+    public static bool operator !=(Range lhs, Range rhs) => lhs.Offset != rhs.Offset;
+
+    public bool Equals(Range other) => Offset == other.Offset;
+
+    public override bool Equals(object obj) => obj is Range other && Equals(other);
+    public int CompareTo(Range other) => Offset.CompareTo(other.Offset);
+    public override int GetHashCode() => Offset.GetHashCode();
+}