perf: avoid full string scans in StrEllipsis - #2557
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UTF8Length and UTF8Copy walk every byte of the input, and StrEllipsis runs for each rendered grid cell, so large TEXT/BLOB values were fully scanned on every paint. Exit early when the byte count already proves there is nothing to cut, and resolve the left-hand cut position with UTF8CodepointToByteIndex, which only walks the first MaxLen codepoints. Output is unchanged - verified against the previous implementation with 10k randomized mixed ASCII/Korean/emoji strings plus boundary cases. Still cuts on UTF-8 codepoint boundaries.
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Follow-up to the discussion on twinn1013/HeidiSQL@713e484e — rebased onto the current lazarus branch, on top of the UTF8Copy-based version.
UTF8LengthandUTF8Copywalk every byte of the input, andStrEllipsisruns for each rendered grid cell, so large TEXT/BLOB values get fully scanned on every paint. This change:UTF8CodepointToByteIndex, which only walks the firstMaxLencodepoints, and truncates in placeOutput is unchanged: verified against the current implementation with 10,000+ randomized mixed ASCII/Korean/emoji strings plus boundary cases — identical results in all of them, so it still cuts on UTF-8 codepoint boundaries and keeps the #2500 fix intact.
Benchmark (200,000 calls on a 10 MB string, MaxLen=100): ~64 ms with this change, while the current implementation needs ~16 ms per single call (it scans the whole 10 MB every time).