Dot Star Regular Expression Matching in PHP

<?php
declare(strict_types=1);
// Dot Star Regular Expression Matching in PHP
//
// PURPOSE
// This small matcher supports whole-sequence matching with a wildcard token and repetition
// of the preceding token.
//
// METHOD
// Use a table of prefix matches. A star can omit its preceding token or consume another
// matching text token. A non-star token extends the previous diagonal.
//
// COMPLEXITY
// O(nm) time and O(nm) space. Only dot and star semantics are supported; this is not a full
// regex engine.
//
// CONTRACT
// Tokens >=0 are literal; -1 is dot and -2 is star in the pattern. Star must follow a
// literal or dot, never another star. Returns 1 or 0.
// Public APIs infer array lengths except in C, which accepts pointer/length pairs. Vertex
// counts and matrix dimensions remain explicit. Arrays must contain signed 32-bit integers.
// Sorted order, correct tree topology, and caller-owned data-structure invariants are
// preconditions; checking them on every query would change query complexity.
// Scalar and shape checks are included. Value-range checks are included where needed to
// prevent invalid indexing or nontermination. Allocation sizes are capped at 4,000,000
// workspace entries. Arithmetic outside Python raises an error on 32-bit overflow; Python
// uses arbitrary precision. Native allocation failures propagate. In-place outputs may be
// partly updated after arithmetic failure. These are single-threaded, in-memory
// implementations.
//
// LANGUAGE DETAILS
// PHP 8.1+ on a 64-bit runtime: packed arrays, strict scalar types, read-only inputs by
// value using copy-on-write, references only for outputs, and checked 32-bit arithmetic.
// Invalid input and overflow throw exceptions. PHP arrays have higher overhead than native
// packed buffers in C/Java.
//
// EXAMPLE
// Expected return: 1.
// Run: php example.php
// Tests for this exact source artifact run before publication. The accompanying source
// archive includes unit cases, runtime results, and source hashes.

function alg_require(bool $valid): void { if (!$valid) throw new InvalidArgumentException("invalid algorithm input"); }
function alg_checked(int|float $v): int { if ($v < -2147483648 || $v > 2147483647 || floor($v) != $v) throw new OverflowException("32-bit result overflow"); return (int)$v; }
function alg_add(int $a,int $b): int { return alg_checked($a+$b); }
function alg_sub(int $a,int $b): int { return alg_checked($a-$b); }
function alg_mul(int $a,int $b): int { return alg_checked($a*$b); }
function alg_size(int $n): int { alg_require($n>=0 && $n<=4000000); return $n; }

function regex_match(array $text, array $pattern): int {
    alg_require(array_is_list($text));
    alg_require(array_is_list($pattern));
    $n = count($text);
    $m = count($pattern);
    alg_require((($n >= 0) && ($n <= 1000000)));
    alg_require((($m >= 0) && ($m <= 1000000)));
    alg_require((count($pattern) == $m));
    alg_require((count($text) == $n));
    for ($alg_i = 0; $alg_i < $m; $alg_i++) {
        alg_require(($pattern[$alg_i] >= alg_sub(0, 2)));
        alg_require((($pattern[$alg_i] != alg_sub(0, 2)) || (($alg_i > 0) && ($pattern[alg_sub($alg_i, 1)] != alg_sub(0, 2)))));
    }
    $dp = array_fill(0, alg_size(alg_mul(alg_add($n, 1), alg_add($m, 1))), 0);
    $dp[0] = 1;
    $i = 0;
    $j = 2;
    while (($j <= $m)) {
        if (($pattern[alg_sub($j, 1)] == alg_sub(0, 2))) {
            $dp[$j] = $dp[alg_sub($j, 2)];
        }
        $j = alg_add($j, 1);
    }
    $i = 1;
    while (($i <= $n)) {
        $j = 1;
        while (($j <= $m)) {
            if (($pattern[alg_sub($j, 1)] == alg_sub(0, 2))) {
                $dp[alg_add(alg_mul($i, alg_add($m, 1)), $j)] = $dp[alg_sub(alg_add(alg_mul($i, alg_add($m, 1)), $j), 2)];
                if ((($pattern[alg_sub($j, 2)] == alg_sub(0, 1)) || ($pattern[alg_sub($j, 2)] == $text[alg_sub($i, 1)]))) {
                    $dp[alg_add(alg_mul($i, alg_add($m, 1)), $j)] = max($dp[alg_add(alg_mul($i, alg_add($m, 1)), $j)], $dp[alg_add(alg_mul(alg_sub($i, 1), alg_add($m, 1)), $j)]);
                }
            } else {
                if ((($pattern[alg_sub($j, 1)] == alg_sub(0, 1)) || ($pattern[alg_sub($j, 1)] == $text[alg_sub($i, 1)]))) {
                    $dp[alg_add(alg_mul($i, alg_add($m, 1)), $j)] = $dp[alg_sub(alg_add(alg_mul(alg_sub($i, 1), alg_add($m, 1)), $j), 1)];
                }
            }
            $j = alg_add($j, 1);
        }
        $i = alg_add($i, 1);
    }
    return $dp[alg_add(alg_mul($n, alg_add($m, 1)), $m)];
}

$text = [1, 1, 2];
$pattern = [1, -2, 2];
$result = regex_match($text, $pattern);
echo $result, PHP_EOL;