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Tweak IndexOfAnyValues.TryGetSingleRange #82786

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Merged
stephentoub merged 1 commit into from
Feb 28, 2023
Merged

Tweak IndexOfAnyValues.TryGetSingleRange #82786

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27 changes: 11 additions & 16 deletions src/libraries/System.Private.CoreLib/src/System/IndexOfAnyValues/IndexOfAnyValues.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,9 +37,9 @@ public static IndexOfAnyValues<byte> Create(ReadOnlySpan<byte> values)
}

// IndexOfAnyValuesInRange is slower than IndexOfAny1Value, but faster than IndexOfAny2Values
if (TryGetSingleRange(values, out byte maxInclusive) is IndexOfAnyValues<byte> range)
if (TryGetSingleRange(values, out byte minInclusive, out byte maxInclusive))
{
return range;
return new IndexOfAnyByteValuesInRange(minInclusive, maxInclusive);
}

if (values.Length <= 5)
Expand Down Expand Up @@ -86,9 +86,11 @@ public static IndexOfAnyValues<char> Create(ReadOnlySpan<char> values)
}

// IndexOfAnyValuesInRange is slower than IndexOfAny1Value, but faster than IndexOfAny2Values
if (TryGetSingleRange(values, out char maxInclusive) is IndexOfAnyValues<char> charRange)
if (TryGetSingleRange(values, out char minInclusive, out char maxInclusive))
{
return charRange;
return PackedSpanHelpers.PackedIndexOfIsSupported && PackedSpanHelpers.CanUsePackedIndexOf(minInclusive) && PackedSpanHelpers.CanUsePackedIndexOf(maxInclusive)
? new IndexOfAnyCharValuesInRange<TrueConst>(minInclusive, maxInclusive)
: new IndexOfAnyCharValuesInRange<FalseConst>(minInclusive, maxInclusive);
}

if (values.Length == 2)
Expand Down Expand Up @@ -144,7 +146,7 @@ ref Unsafe.As<char, short>(ref MemoryMarshal.GetReference(values)),
return new IndexOfAnyCharValuesProbabilistic(values);
}

private static unsafe IndexOfAnyValues<T>? TryGetSingleRange<T>(ReadOnlySpan<T> values, out T maxInclusive)
private static bool TryGetSingleRange<T>(ReadOnlySpan<T> values, out T minInclusive, out T maxInclusive)
where T : struct, INumber<T>, IMinMaxValue<T>
{
T min = T.MaxValue;
Expand All @@ -156,12 +158,13 @@ ref Unsafe.As<char, short>(ref MemoryMarshal.GetReference(values)),
max = T.Max(max, value);
}

minInclusive = min;
maxInclusive = max;

uint range = uint.CreateChecked(max - min) + 1;
if (range > values.Length)
{
return null;
return false;
}

Span<bool> seenValues = range <= 256 ? stackalloc bool[256] : new bool[range];
Expand All @@ -176,18 +179,10 @@ ref Unsafe.As<char, short>(ref MemoryMarshal.GetReference(values)),

if (seenValues.Contains(false))
{
return null;
return false;
}

if (typeof(T) == typeof(byte))
{
return (IndexOfAnyValues<T>)(object)new IndexOfAnyByteValuesInRange(byte.CreateChecked(min), byte.CreateChecked(max));
}

Debug.Assert(typeof(T) == typeof(char));
return (IndexOfAnyValues<T>)(object)(PackedSpanHelpers.PackedIndexOfIsSupported && PackedSpanHelpers.CanUsePackedIndexOf(min) && PackedSpanHelpers.CanUsePackedIndexOf(max)
? new IndexOfAnyCharValuesInRange<TrueConst>(*(char*)&min, *(char*)&max)
: new IndexOfAnyCharValuesInRange<FalseConst>(*(char*)&min, *(char*)&max));
return true;
}

internal interface IRuntimeConst
Expand Down