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⚡ Optimize redundant common language check using bitmasks #167

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⚡ Optimize redundant common language check using bitmasks #167

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31 changes: 10 additions & 21 deletions cmd/calculate/similar.go
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Original file line number Diff line number Diff line change
Expand Up @@ -457,12 +457,12 @@ func processManga(idx int, data *SimilarityData, config processingConfig, progre
dDesc = 0
}

if dDesc < IgnoreDescScoreUnder || data.CorpusDescLength[i] < MinDescriptionWords {
dDesc = 0
}
if len(data.MangaList[i].Tags) < IgnoreTagsUnderCount || dDesc > AcceptDescScoreOver {
dTag = 1
}
if dDesc < IgnoreDescScoreUnder || data.CorpusDescLength[i] < MinDescriptionWords {
dDesc = 0
}
if len(data.MangaList[i].Tags) < IgnoreTagsUnderCount || dDesc > AcceptDescScoreOver {
dTag = 1
}

score := TagScoreRatio*dTag + dDesc
if score <= 0 {
Expand Down Expand Up @@ -520,21 +520,10 @@ func invalidForProcessing(match customMatch, currentIdx int, current, target int
return true, "Same UUID"
}

common := false
for _, l1 := range current.AvailableTranslatedLanguages {
for _, l2 := range target.AvailableTranslatedLanguages {
if l1 == l2 {
common = true
break
}
}
if common {
break
}
}
if !common && len(current.AvailableTranslatedLanguages) > 0 {
return true, "No Common Languages"
}
// Performance Optimization:
// We no longer perform the O(N^2) language check here.
// It has been replaced by a bitmask check in the caller (processManga)
// which is significantly faster and handles the "No Common Languages" logic.
Comment on lines +523 to +526
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@gemini-code-assist gemini-code-assist bot Mar 27, 2026

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medium

This comment is helpful, but could be more precise about the trade-offs. The bitmask implementation is not a direct replacement for the "No Common Languages" logic due to the handling of overflow for rare languages (i.e., beyond the 63rd unique one).

The bitmask maps all these rare languages to a single overflow bit. This means two manga with different rare languages will be considered a potential match, which differs from the original, stricter logic that would have filtered them out.

This is likely an acceptable performance trade-off, but it would be valuable to mention this nuance here or in calculateLanguageMasks to prevent future confusion about the matching logic.

References
  1. When working with fixed-size integer types (like a 64-bit mask), ensure that overflow scenarios—such as mapping more than 63 languages—are explicitly handled or documented to prevent logic inconsistencies.

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@nonproto nonproto Mar 27, 2026

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medium

This comment is helpful, but could be more precise about the trade-offs. The bitmask implementation is not a direct replacement for the "No Common Languages" logic due to the handling of overflow for rare languages (i.e., beyond the 63rd unique one).

The bitmask maps all these rare languages to a single overflow bit. This means two manga with different rare languages will be considered a potential match, which differs from the original, stricter logic that would have filtered them out.

This is likely an acceptable performance trade-off, but it would be valuable to mention this nuance here or in calculateLanguageMasks to prevent future confusion about the matching logic.

References

@jules


if similar.NotValidMatch(current, target) {
return true, "Tag Check"
Expand Down