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Fix edge cases in EmphasisInlineParser #902

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Merged
xoofx merged 1 commit into from
Oct 17, 2025
+11 −6
Merged

Fix edge cases in EmphasisInlineParser #902

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3 changes: 3 additions & 0 deletions src/Markdig.Tests/TestEmphasisExtended.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -148,6 +148,9 @@ class CustomEmphasisInline : EmphasisInline { }
[TestCase("1Foo1", "<one-only>Foo</one-only>")]
[TestCase("1121", "1<one-only>2</one-only>")]
[TestCase("22322", "<two-only>3</two-only>")]
[TestCase("2223222", "2<two-only>32</two-only>")]
[TestCase("22223222", "22<two-only>32</two-only>")]
[TestCase("22223223222", "22223<two-only>3</two-only>2")]
[TestCase("2232", "2232")]
[TestCase("333", "333")]
[TestCase("3334333", "<three-only>4</three-only>")]
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2 changes: 1 addition & 1 deletion src/Markdig/Helpers/UnicodeUtility.cs
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Expand Up @@ -22,7 +22,7 @@ public static bool IsValidUnicodeScalar(uint value)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void GetUtf16SurrogatesFromSupplementaryPlaneScalar(uint value, out char highSurrogateCodePoint, out char lowSurrogateCodePoint)
{
Debug.Assert(IsValidUnicodeScalar(value) && IsBmpCodePoint(value));
Debug.Assert(IsValidUnicodeScalar(value) && !IsBmpCodePoint(value));

highSurrogateCodePoint = (char)((value + ((0xD800u - 0x40u) << 10)) >> 10);
lowSurrogateCodePoint = (char)((value & 0x3FFu) + 0xDC00u);
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2 changes: 2 additions & 0 deletions src/Markdig/Parsers/Inlines/EmphasisDescriptor.cs
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Expand Up @@ -3,12 +3,14 @@
// See the license.txt file in the project root for more information.

using Markdig.Helpers;
using System.Diagnostics;

namespace Markdig.Parsers.Inlines;

/// <summary>
/// Descriptor for an emphasis.
/// </summary>
[DebuggerDisplay("Emphasis Char={Character}, Min={MinimumCount}, Max={MaximumCount}, EnableWithinWord={EnableWithinWord}")]
public sealed class EmphasisDescriptor
{
/// <summary>
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10 changes: 5 additions & 5 deletions src/Markdig/Parsers/Inlines/EmphasisInlineParser.cs
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Expand Up @@ -233,9 +233,9 @@ private void ProcessEmphasis(InlineProcessor processor, List<EmphasisDelimiterIn
continue;
}

if ((closeDelimiter.Type & DelimiterType.Close) != 0 && closeDelimiter.DelimiterCount >= emphasisDesc.MinimumCount)
if ((closeDelimiter.Type & DelimiterType.Close) != 0)
{
while (true)
while (closeDelimiter.DelimiterCount >= emphasisDesc.MinimumCount)
{
// Now, look back in the stack (staying above stack_bottom and the openers_bottom for this delimiter type)
// for the first matching potential opener (“matching” means same delimiter).
Expand All @@ -245,8 +245,7 @@ private void ProcessEmphasis(InlineProcessor processor, List<EmphasisDelimiterIn
{
var previousOpenDelimiter = delimiters[j];

var isOddMatch = ((closeDelimiter.Type & DelimiterType.Open) != 0 ||
(previousOpenDelimiter.Type & DelimiterType.Close) != 0) &&
var isOddMatch = ((closeDelimiter.Type & DelimiterType.Open) != 0 || (previousOpenDelimiter.Type & DelimiterType.Close) != 0) &&
previousOpenDelimiter.DelimiterCount != closeDelimiter.DelimiterCount &&
(previousOpenDelimiter.DelimiterCount + closeDelimiter.DelimiterCount) % 3 == 0 &&
(previousOpenDelimiter.DelimiterCount % 3 != 0 || closeDelimiter.DelimiterCount % 3 != 0);
Expand Down Expand Up @@ -357,7 +356,8 @@ private void ProcessEmphasis(InlineProcessor processor, List<EmphasisDelimiterIn
}

// The current delimiters are matching
if (openDelimiter.DelimiterCount >= emphasisDesc.MinimumCount)
if (openDelimiter.DelimiterCount >= emphasisDesc.MinimumCount &&
closeDelimiter.DelimiterCount >= emphasisDesc.MinimumCount)
{
goto process_delims;
}
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