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This pull request optimizes `FindEmojiSubmatchIndex` in Gitea's emoji package (`modules/emoji/emoji.go`) by replacing the `strings.Replacer`-based search with a slice-based trie and a constant-time starting-byte check (`isStartingByte`). The new implementation avoids heap allocations during the search and reduces CPU overhead when rendering Markdown, particularly for plain text that does not contain emojis. ### Verification Verified with unit tests: ```sh go test -count=1 ./modules/emoji/... ``` Benchmarks: ```sh go test -bench=. -benchmem ./modules/emoji/... ``` ### Results | Benchmark | Before | After | | ---------- | ------ | ----- | | `BenchmarkFindEmojiSubmatchIndex` | 168.3 ns/op, 2 allocs/op | 85.78 ns/op, 1 alloc/op | | `BenchmarkFindEmojiSubmatchIndexNoMatch` | 239.8 ns/op, 1 alloc/op | 105.1 ns/op, 0 allocs/op | ### Benchmark Output ```text goos: linux goarch: amd64 pkg: gitea.dev/modules/emoji cpu: Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz BenchmarkFindEmojiSubmatchIndex-4 13498539 85.78 ns/op 16 B/op 1 allocs/op BenchmarkFindEmojiSubmatchIndexNoMatch-4 11220450 105.1 ns/op 0 B/op 0 allocs/op BenchmarkFindEmojiSubmatchIndexOld-4 6569360 168.3 ns/op 48 B/op 2 allocs/op BenchmarkFindEmojiSubmatchIndexOldNoMatch-4 5026116 239.8 ns/op 32 B/op 1 allocs/op ``` --------- Signed-off-by: Sudhanshu Singh <sudhanshuwriterblc@gmail.com> Co-authored-by: silverwind <me@silverwind.io> Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>