/**
* Splits a pattern in segments and patterns.
* segments will be represented by string value and patterns by an array containing
* the string pattern as first value and the greedy value as second value.
*
* example:
* `/user[/{id}]*` will gives `['/user', ['id', '*']]`
*
* Unfortunately recursive regex matcher can't help here so this function is required.
*
* @param string $pattern A route pattern.
* @param array The splitted pattern.
*/
public static function split($pattern)
{
$segments = [];
$len = strlen($pattern);
$buffer = '';
$opened = 0;
for ($i = 0; $i < $len; $i++) {
if ($pattern[$i] === '{') {
do {
$buffer .= $pattern[$i++];
if ($pattern[$i] === '}') {
$buffer .= $pattern[$i];
break;
}
} while ($i < $len);
} elseif ($pattern[$i] === '[') {
$opened++;
if ($opened === 1) {
$segments[] = $buffer;
$buffer = '';
} else {
$buffer .= $pattern[$i];
}
} elseif ($pattern[$i] === ']') {
$opened--;
if ($opened === 0) {
$greedy = '?';
if ($i < $len - 1) {
if ($pattern[$i + 1] === '*' || $pattern[$i + 1] === '+') {
$greedy = $pattern[$i + 1];
$i++;
}
}
$segments[] = [$buffer, $greedy];
$buffer = '';
} else {
$buffer .= $pattern[$i];
}
} else {
$buffer .= $pattern[$i];
}
}
if ($buffer) {
$segments[] = $buffer;
}
if ($opened) {
throw ParserException::squareBracketMismatch();
}
return $segments;
}
