[ArtUkrainskiy]

This PR contains the current implementation in ext/strmatch. The RFC proposes integration into ext/standard; the final placement and naming remain open for discussion.

RFC: https://wiki.php.net/rfc/prepared_literal_string_matching

Discussion: https://news-web.php.net/php.internals/133028

I propose Str\Matcher and Str\Replacer for preparing a fixed literal dictionary once and using it across multiple texts. Matcher supports presence checks, unique matched keys, counting and enumerating overlapping occurrences; Str\MatchResult exposes byte offsets, lengths and keys. Replacer selects the earliest match, preferring the longest key at that position, and does not rescan inserted text.

Both classes capture an immutable dictionary and use Aho–Corasick with hybrid dense/sparse transitions. Matching is byte-oriented, binary-safe and case-sensitive. Reuse is within one request or a long-running process.

AMD Ryzen 9 5950X, Linux x86-64, GCC 15.2 / Clang 21.1. Times are medians; parentheses show median paired elapsed-time changes against the fastest eligible existing method in each measurement. Negative percentages mean faster; slowdowns of at least 2× are shown as ×N slower. Prepared includes the call and result release on an existing object; one-shot also includes construction and destruction. Existing methods use prebuilt arguments and warm PCRE caches. The displayed existing-method times are medians from the one-shot comparisons; prepared calls have separately measured references.

Operation / exact input	Best existing method / time	GCC prepared, µs	GCC one-shot, µs	Clang prepared, µs	Clang one-shot, µs
matches(); 128 B; 128 keys; no matches	preg_match() GCC: 3.048 µs Clang: 3.038 µs	0.186 (-93.88%)	52.553 (×17.2 slower)	0.164 (-94.63%)	51.907 (×17.1 slower)
matches(); 4 KiB; 128 keys; no matches	preg_match() GCC: 100.021 µs Clang: 100.014 µs	3.817 (-96.18%)	58.107 (-42.02%)	3.428 (-96.57%)	56.359 (-43.72%)
matches(); 4 KiB; 128 keys; hit at byte 8	preg_match() GCC: 0.414 µs Clang: 0.408 µs	0.116 (-71.84%)†	52.787 (×127.4 slower)	0.110 (-72.94%)	52.310 (×128.1 slower)
matches(); 4 KiB; 128 keys; hit at byte 2042	preg_match() GCC: 51.972 µs Clang: 51.897 µs	1.986 (-96.17%)	54.966 (+5.90%)	1.694 (-96.73%)	54.147 (+4.43%)
matches(); 4 KiB; 128 keys; hit at byte 4076	str_contains() loop GCC: 60.558 µs Clang: 56.447 µs	3.814 (-93.66%)	57.599 (-4.94%)	3.364 (-94.03%)	55.063 (-2.40%)
matches(); 32 KiB; 1024 keys; no matches	str_contains() loop GCC: 7699.530 µs Clang: 7317.499 µs	78.008 (-98.98%)	848.164 (-88.98%)	74.420 (-98.97%)	858.186 (-88.27%)
getMatchedKeywords(); 4 KiB; 128 keys; 1 occurrence	preg_match_all() GCC: 102.852 µs Clang: 102.811 µs	4.317 (-95.79%)	58.478 (-43.01%)	3.499 (-96.60%)	56.524 (-45.20%)
getMatchedKeywords(); natural EN text, 12828 B; 128 keys; 23 occurrences, 12 unique keys	strpos() loop GCC: 307.035 µs Clang: 289.993 µs	19.341 (-93.68%)	95.719 (-68.77%)	17.473 (-93.96%)	97.458 (-66.38%)
countMatches(); 4 KiB; 128 keys; 1 occurrence	preg_match_all() GCC: 101.504 µs Clang: 101.701 µs	4.739 (-95.34%)	66.663 (-34.34%)	3.363 (-96.68%)	56.827 (-44.07%)
matchAll(); 64 KiB; 128 keys; 1 occurrence	preg_match_all() GCC: 1610.465 µs Clang: 1614.484 µs	193.198 (-88.00%)	278.040 (-82.73%)	185.683 (-88.49%)	272.581 (-83.11%)
matchAll(); 64 KiB; the same 128 keys; 64 occurrences, 4 unique keys	preg_match_all() GCC: 1695.893 µs Clang: 1702.396 µs	196.443 (-88.42%)	280.789 (-83.43%)	188.806 (-88.97%)	276.099 (-83.77%)
replace(); 1 KiB; 32 keys; 2 replacements	preg_replace_callback() GCC: 2.422 µs Clang: 2.566 µs	1.436 (-40.71%)	14.887 (×6.1 slower)	1.348 (-47.55%)	15.270 (×6.0 slower)
replace(); 4 KiB; the same 32 keys; 0 replacements	preg_replace_callback() GCC: 8.482 µs Clang: 8.173 µs	5.939 (-29.86%)	19.350 (×2.3 slower)	5.659 (-30.80%)	19.725 (×2.4 slower)
replace(); 4 KiB; the same 32 keys; 16 replacements	preg_replace_callback() GCC: 9.380 µs Clang: 9.221 µs	6.247 (-33.42%)	19.790 (×2.1 slower)	6.120 (-33.61%)	20.173 (×2.2 slower)
replace(); 16 KiB; the same 32 keys; 16 replacements	preg_replace_callback() GCC: 62.595 µs Clang: 61.774 µs	26.065 (-58.33%)	40.257 (-35.67%)	24.968 (-59.62%)	39.583 (-36.06%)
replace(); 4 KiB; 1 key of 8 B; 5 replacements	strtr() GCC: 0.400 µs Clang: 0.390 µs	4.080 (×10.2 slower)	4.462 (×11.2 slower)	2.609 (×6.7 slower)	2.971 (×7.6 slower)
replace(); 1 MiB; 1000 keys of 8–24 B; 1000 replacements	preg_replace_callback() GCC: 13762.732 µs Clang: 13679.984 µs	1550.727 (-88.73%)	2932.962 (-78.70%)	1290.924 (-90.57%)	2747.874 (-79.90%)
replace(); 1 MiB; 10000 keys of 16 B; 0 replacements	strtr() GCC: 7045.148 µs Clang: 6573.642 µs	1466.895 (-79.15%)	32658.311 (×4.6 slower)	1185.057 (-81.97%)	32827.694 (×5.0 slower)
replace(); the same 1 MiB text; 10000 keys of 8–24 B; 0 replacements	strtr() GCC: 89600.329 µs Clang: 89526.581 µs	1489.095 (-98.34%)	32682.993 (-63.52%)	1196.013 (-98.66%)	32943.512 (-63.24%)
replace(); 1 MiB; 1000 keys in {{…}} format; 100 replacements	specialized preg_replace_callback() GCC: 63.977 µs Clang: 64.276 µs	1148.500 (×18.0 slower)	1471.567 (×23.0 slower)	1054.442 (×16.4 slower)	1372.608 (×21.4 slower)

Each row uses one fixed text and dictionary. Controlled Matcher keys are 12 B; the natural-text dictionary uses keys of 4–28 B. In the three positive matches() rows, the matching key is #65 in dictionary order. The 32-key Replacer rows share keys of 11–21 B and same-length replacement values.

For {{…}} keys, the specialized PCRE expression finds candidates and looks them up in the dictionary. These cases illustrate different trade-offs, not universal thresholds or production workload frequencies. † Observed time only: the measurement did not pass quality checks.

The extension builds with -Werror on GCC and Clang; 16 PHPT tests pass on both. Independent output checks pass under ASan/UBSan.

Full results, memory costs, exact inputs, correctness logs and reproduction.

[TimWolla]

This absolutely should be part of ext/standard. Making it a separate extension is needless (maintenance) overhead.