Optimize Cursor: skip strrpos on tab-free documents#1119
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benchmark_parse.php measures only the parsing phase (converter initialized once outside the loop) unlike benchmark.php which re-creates the converter on every iteration. Reports min/median/p95/mean over N iterations (default 100 + 10 warmup).
The Cursor constructor previously called strrpos() on every line to find the last tab position, even for documents with no tabs. For tab-free documents (the common case), this was pure overhead — strrpos scans the string backwards and costs 40–165 ns per line depending on length. MarkdownParser now scans the whole document once with str_contains() before the parse loop. When no tabs are found, each Cursor is constructed with $lineCouldHaveTabs=false, setting lastTabPosition=false directly without calling strrpos. Benchmarks (warm, 100 iterations, CommonMarkConverter, sample.md 27 KB): Before: median 4.38 ms After: median 3.92 ms (-10.5%)
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Cursor::__construct()calledstrrpos($line, "\t")on every line to locate the last tab position. For tab-free documents this is a full backward scan for no benefit — 40–165 ns/line depending on length.MarkdownParser::parse()now scans the document once withstr_contains()(~3 µs). When no tabs are found,new Cursor($line, false)setslastTabPosition = falsedirectly without callingstrrpos. The$lineCouldHaveTabsparameter defaults totrue, keeping the public API backward compatible.Benchmarks run with
tests/benchmark/benchmark_parse.php(new warm script: converter initialized once, 100 iterations + 10 warmup,hrtime()). PHP 8.5.2, OPcache on, Xdebug off.sample.md(27 KB, 2.9% tabs):Larger corpora from vendor (not committed): CHANGELOG.md 570 KB −5.2%, spec.txt 200 KB −2.8%.