1<?php
2
3/*
4 * This file is part of the Symfony package.
5 *
6 * (c) Fabien Potencier <fabien@symfony.com>
7 *
8 * For the full copyright and license information, please view the LICENSE
9 * file that was distributed with this source code.
10 */
11
12namespace Symfony\Component\Yaml;
13
14use Symfony\Component\Yaml\Exception\DumpException;
15use Symfony\Component\Yaml\Exception\ParseException;
16use Symfony\Component\Yaml\Tag\TaggedValue;
17
18/**
19 * Inline implements a YAML parser/dumper for the YAML inline syntax.
20 *
21 * @author Fabien Potencier <fabien@symfony.com>
22 *
23 * @internal
24 */
25class Inline
26{
27    const REGEX_QUOTED_STRING = '(?:"([^"\\\\]*+(?:\\\\.[^"\\\\]*+)*+)"|\'([^\']*+(?:\'\'[^\']*+)*+)\')';
28
29    public static $parsedLineNumber = -1;
30    public static $parsedFilename;
31
32    private static $exceptionOnInvalidType = false;
33    private static $objectSupport = false;
34    private static $objectForMap = false;
35    private static $constantSupport = false;
36
37    public static function initialize(int $flags, int $parsedLineNumber = null, string $parsedFilename = null)
38    {
39        self::$exceptionOnInvalidType = (bool) (Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE & $flags);
40        self::$objectSupport = (bool) (Yaml::PARSE_OBJECT & $flags);
41        self::$objectForMap = (bool) (Yaml::PARSE_OBJECT_FOR_MAP & $flags);
42        self::$constantSupport = (bool) (Yaml::PARSE_CONSTANT & $flags);
43        self::$parsedFilename = $parsedFilename;
44
45        if (null !== $parsedLineNumber) {
46            self::$parsedLineNumber = $parsedLineNumber;
47        }
48    }
49
50    /**
51     * Converts a YAML string to a PHP value.
52     *
53     * @param string $value      A YAML string
54     * @param int    $flags      A bit field of PARSE_* constants to customize the YAML parser behavior
55     * @param array  $references Mapping of variable names to values
56     *
57     * @return mixed A PHP value
58     *
59     * @throws ParseException
60     */
61    public static function parse(string $value = null, int $flags = 0, array $references = [])
62    {
63        self::initialize($flags);
64
65        $value = trim($value);
66
67        if ('' === $value) {
68            return '';
69        }
70
71        if (2 /* MB_OVERLOAD_STRING */ & (int) ini_get('mbstring.func_overload')) {
72            $mbEncoding = mb_internal_encoding();
73            mb_internal_encoding('ASCII');
74        }
75
76        try {
77            $i = 0;
78            $tag = self::parseTag($value, $i, $flags);
79            switch ($value[$i]) {
80                case '[':
81                    $result = self::parseSequence($value, $flags, $i, $references);
82                    ++$i;
83                    break;
84                case '{':
85                    $result = self::parseMapping($value, $flags, $i, $references);
86                    ++$i;
87                    break;
88                default:
89                    $result = self::parseScalar($value, $flags, null, $i, null === $tag, $references);
90            }
91
92            // some comments are allowed at the end
93            if (preg_replace('/\s+#.*$/A', '', substr($value, $i))) {
94                throw new ParseException(sprintf('Unexpected characters near "%s".', substr($value, $i)), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
95            }
96
97            if (null !== $tag && '' !== $tag) {
98                return new TaggedValue($tag, $result);
99            }
100
101            return $result;
102        } finally {
103            if (isset($mbEncoding)) {
104                mb_internal_encoding($mbEncoding);
105            }
106        }
107    }
108
109    /**
110     * Dumps a given PHP variable to a YAML string.
111     *
112     * @param mixed $value The PHP variable to convert
113     * @param int   $flags A bit field of Yaml::DUMP_* constants to customize the dumped YAML string
114     *
115     * @return string The YAML string representing the PHP value
116     *
117     * @throws DumpException When trying to dump PHP resource
118     */
119    public static function dump($value, int $flags = 0): string
120    {
121        switch (true) {
122            case \is_resource($value):
123                if (Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE & $flags) {
124                    throw new DumpException(sprintf('Unable to dump PHP resources in a YAML file ("%s").', get_resource_type($value)));
125                }
126
127                return self::dumpNull($flags);
128            case $value instanceof \DateTimeInterface:
129                return $value->format('c');
130            case \is_object($value):
131                if ($value instanceof TaggedValue) {
132                    return '!'.$value->getTag().' '.self::dump($value->getValue(), $flags);
133                }
134
135                if (Yaml::DUMP_OBJECT & $flags) {
136                    return '!php/object '.self::dump(serialize($value));
137                }
138
139                if (Yaml::DUMP_OBJECT_AS_MAP & $flags && ($value instanceof \stdClass || $value instanceof \ArrayObject)) {
140                    $output = [];
141
142                    foreach ($value as $key => $val) {
143                        $output[] = sprintf('%s: %s', self::dump($key, $flags), self::dump($val, $flags));
144                    }
145
146                    return sprintf('{ %s }', implode(', ', $output));
147                }
148
149                if (Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE & $flags) {
150                    throw new DumpException('Object support when dumping a YAML file has been disabled.');
151                }
152
153                return self::dumpNull($flags);
154            case \is_array($value):
155                return self::dumpArray($value, $flags);
156            case null === $value:
157                return self::dumpNull($flags);
158            case true === $value:
159                return 'true';
160            case false === $value:
161                return 'false';
162            case ctype_digit($value):
163                return \is_string($value) ? "'$value'" : (int) $value;
164            case is_numeric($value):
165                $locale = setlocale(LC_NUMERIC, 0);
166                if (false !== $locale) {
167                    setlocale(LC_NUMERIC, 'C');
168                }
169                if (\is_float($value)) {
170                    $repr = (string) $value;
171                    if (is_infinite($value)) {
172                        $repr = str_ireplace('INF', '.Inf', $repr);
173                    } elseif (floor($value) == $value && $repr == $value) {
174                        // Preserve float data type since storing a whole number will result in integer value.
175                        $repr = '!!float '.$repr;
176                    }
177                } else {
178                    $repr = \is_string($value) ? "'$value'" : (string) $value;
179                }
180                if (false !== $locale) {
181                    setlocale(LC_NUMERIC, $locale);
182                }
183
184                return $repr;
185            case '' == $value:
186                return "''";
187            case self::isBinaryString($value):
188                return '!!binary '.base64_encode($value);
189            case Escaper::requiresDoubleQuoting($value):
190                return Escaper::escapeWithDoubleQuotes($value);
191            case Escaper::requiresSingleQuoting($value):
192            case Parser::preg_match('{^[0-9]+[_0-9]*$}', $value):
193            case Parser::preg_match(self::getHexRegex(), $value):
194            case Parser::preg_match(self::getTimestampRegex(), $value):
195                return Escaper::escapeWithSingleQuotes($value);
196            default:
197                return $value;
198        }
199    }
200
201    /**
202     * Check if given array is hash or just normal indexed array.
203     *
204     * @param array|\ArrayObject|\stdClass $value The PHP array or array-like object to check
205     *
206     * @return bool true if value is hash array, false otherwise
207     */
208    public static function isHash($value): bool
209    {
210        if ($value instanceof \stdClass || $value instanceof \ArrayObject) {
211            return true;
212        }
213
214        $expectedKey = 0;
215
216        foreach ($value as $key => $val) {
217            if ($key !== $expectedKey++) {
218                return true;
219            }
220        }
221
222        return false;
223    }
224
225    /**
226     * Dumps a PHP array to a YAML string.
227     *
228     * @param array $value The PHP array to dump
229     * @param int   $flags A bit field of Yaml::DUMP_* constants to customize the dumped YAML string
230     *
231     * @return string The YAML string representing the PHP array
232     */
233    private static function dumpArray(array $value, int $flags): string
234    {
235        // array
236        if (($value || Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE & $flags) && !self::isHash($value)) {
237            $output = [];
238            foreach ($value as $val) {
239                $output[] = self::dump($val, $flags);
240            }
241
242            return sprintf('[%s]', implode(', ', $output));
243        }
244
245        // hash
246        $output = [];
247        foreach ($value as $key => $val) {
248            $output[] = sprintf('%s: %s', self::dump($key, $flags), self::dump($val, $flags));
249        }
250
251        return sprintf('{ %s }', implode(', ', $output));
252    }
253
254    private static function dumpNull(int $flags): string
255    {
256        if (Yaml::DUMP_NULL_AS_TILDE & $flags) {
257            return '~';
258        }
259
260        return 'null';
261    }
262
263    /**
264     * Parses a YAML scalar.
265     *
266     * @return mixed
267     *
268     * @throws ParseException When malformed inline YAML string is parsed
269     */
270    public static function parseScalar(string $scalar, int $flags = 0, array $delimiters = null, int &$i = 0, bool $evaluate = true, array $references = [])
271    {
272        if (\in_array($scalar[$i], ['"', "'"], true)) {
273            // quoted scalar
274            $output = self::parseQuotedScalar($scalar, $i);
275
276            if (null !== $delimiters) {
277                $tmp = ltrim(substr($scalar, $i), " \n");
278                if ('' === $tmp) {
279                    throw new ParseException(sprintf('Unexpected end of line, expected one of "%s".', implode('', $delimiters)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
280                }
281                if (!\in_array($tmp[0], $delimiters)) {
282                    throw new ParseException(sprintf('Unexpected characters (%s).', substr($scalar, $i)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
283                }
284            }
285        } else {
286            // "normal" string
287            if (!$delimiters) {
288                $output = substr($scalar, $i);
289                $i += \strlen($output);
290
291                // remove comments
292                if (Parser::preg_match('/[ \t]+#/', $output, $match, PREG_OFFSET_CAPTURE)) {
293                    $output = substr($output, 0, $match[0][1]);
294                }
295            } elseif (Parser::preg_match('/^(.*?)('.implode('|', $delimiters).')/', substr($scalar, $i), $match)) {
296                $output = $match[1];
297                $i += \strlen($output);
298                $output = trim($output);
299            } else {
300                throw new ParseException(sprintf('Malformed inline YAML string: "%s".', $scalar), self::$parsedLineNumber + 1, null, self::$parsedFilename);
301            }
302
303            // a non-quoted string cannot start with @ or ` (reserved) nor with a scalar indicator (| or >)
304            if ($output && ('@' === $output[0] || '`' === $output[0] || '|' === $output[0] || '>' === $output[0] || '%' === $output[0])) {
305                throw new ParseException(sprintf('The reserved indicator "%s" cannot start a plain scalar; you need to quote the scalar.', $output[0]), self::$parsedLineNumber + 1, $output, self::$parsedFilename);
306            }
307
308            if ($evaluate) {
309                $output = self::evaluateScalar($output, $flags, $references);
310            }
311        }
312
313        return $output;
314    }
315
316    /**
317     * Parses a YAML quoted scalar.
318     *
319     * @throws ParseException When malformed inline YAML string is parsed
320     */
321    private static function parseQuotedScalar(string $scalar, int &$i): string
322    {
323        if (!Parser::preg_match('/'.self::REGEX_QUOTED_STRING.'/Au', substr($scalar, $i), $match)) {
324            throw new ParseException(sprintf('Malformed inline YAML string: "%s".', substr($scalar, $i)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
325        }
326
327        $output = substr($match[0], 1, -1);
328
329        $unescaper = new Unescaper();
330        if ('"' == $scalar[$i]) {
331            $output = $unescaper->unescapeDoubleQuotedString($output);
332        } else {
333            $output = $unescaper->unescapeSingleQuotedString($output);
334        }
335
336        $i += \strlen($match[0]);
337
338        return $output;
339    }
340
341    /**
342     * Parses a YAML sequence.
343     *
344     * @throws ParseException When malformed inline YAML string is parsed
345     */
346    private static function parseSequence(string $sequence, int $flags, int &$i = 0, array $references = []): array
347    {
348        $output = [];
349        $len = \strlen($sequence);
350        ++$i;
351
352        // [foo, bar, ...]
353        while ($i < $len) {
354            if (']' === $sequence[$i]) {
355                return $output;
356            }
357            if (',' === $sequence[$i] || ' ' === $sequence[$i]) {
358                ++$i;
359
360                continue;
361            }
362
363            $tag = self::parseTag($sequence, $i, $flags);
364            switch ($sequence[$i]) {
365                case '[':
366                    // nested sequence
367                    $value = self::parseSequence($sequence, $flags, $i, $references);
368                    break;
369                case '{':
370                    // nested mapping
371                    $value = self::parseMapping($sequence, $flags, $i, $references);
372                    break;
373                default:
374                    $isQuoted = \in_array($sequence[$i], ['"', "'"], true);
375                    $value = self::parseScalar($sequence, $flags, [',', ']'], $i, null === $tag, $references);
376
377                    // the value can be an array if a reference has been resolved to an array var
378                    if (\is_string($value) && !$isQuoted && false !== strpos($value, ': ')) {
379                        // embedded mapping?
380                        try {
381                            $pos = 0;
382                            $value = self::parseMapping('{'.$value.'}', $flags, $pos, $references);
383                        } catch (\InvalidArgumentException $e) {
384                            // no, it's not
385                        }
386                    }
387
388                    --$i;
389            }
390
391            if (null !== $tag && '' !== $tag) {
392                $value = new TaggedValue($tag, $value);
393            }
394
395            $output[] = $value;
396
397            ++$i;
398        }
399
400        throw new ParseException(sprintf('Malformed inline YAML string: "%s".', $sequence), self::$parsedLineNumber + 1, null, self::$parsedFilename);
401    }
402
403    /**
404     * Parses a YAML mapping.
405     *
406     * @return array|\stdClass
407     *
408     * @throws ParseException When malformed inline YAML string is parsed
409     */
410    private static function parseMapping(string $mapping, int $flags, int &$i = 0, array $references = [])
411    {
412        $output = [];
413        $len = \strlen($mapping);
414        ++$i;
415        $allowOverwrite = false;
416
417        // {foo: bar, bar:foo, ...}
418        while ($i < $len) {
419            switch ($mapping[$i]) {
420                case ' ':
421                case ',':
422                case "\n":
423                    ++$i;
424                    continue 2;
425                case '}':
426                    if (self::$objectForMap) {
427                        return (object) $output;
428                    }
429
430                    return $output;
431            }
432
433            // key
434            $offsetBeforeKeyParsing = $i;
435            $isKeyQuoted = \in_array($mapping[$i], ['"', "'"], true);
436            $key = self::parseScalar($mapping, $flags, [':', ' '], $i, false, []);
437
438            if ($offsetBeforeKeyParsing === $i) {
439                throw new ParseException('Missing mapping key.', self::$parsedLineNumber + 1, $mapping);
440            }
441
442            if ('!php/const' === $key) {
443                $key .= ' '.self::parseScalar($mapping, $flags, [':'], $i, false, []);
444                $key = self::evaluateScalar($key, $flags);
445            }
446
447            if (false === $i = strpos($mapping, ':', $i)) {
448                break;
449            }
450
451            if (!$isKeyQuoted) {
452                $evaluatedKey = self::evaluateScalar($key, $flags, $references);
453
454                if ('' !== $key && $evaluatedKey !== $key && !\is_string($evaluatedKey) && !\is_int($evaluatedKey)) {
455                    throw new ParseException('Implicit casting of incompatible mapping keys to strings is not supported. Quote your evaluable mapping keys instead.', self::$parsedLineNumber + 1, $mapping);
456                }
457            }
458
459            if (!$isKeyQuoted && (!isset($mapping[$i + 1]) || !\in_array($mapping[$i + 1], [' ', ',', '[', ']', '{', '}', "\n"], true))) {
460                throw new ParseException('Colons must be followed by a space or an indication character (i.e. " ", ",", "[", "]", "{", "}").', self::$parsedLineNumber + 1, $mapping);
461            }
462
463            if ('<<' === $key) {
464                $allowOverwrite = true;
465            }
466
467            while ($i < $len) {
468                if (':' === $mapping[$i] || ' ' === $mapping[$i] || "\n" === $mapping[$i]) {
469                    ++$i;
470
471                    continue;
472                }
473
474                $tag = self::parseTag($mapping, $i, $flags);
475                switch ($mapping[$i]) {
476                    case '[':
477                        // nested sequence
478                        $value = self::parseSequence($mapping, $flags, $i, $references);
479                        // Spec: Keys MUST be unique; first one wins.
480                        // Parser cannot abort this mapping earlier, since lines
481                        // are processed sequentially.
482                        // But overwriting is allowed when a merge node is used in current block.
483                        if ('<<' === $key) {
484                            foreach ($value as $parsedValue) {
485                                $output += $parsedValue;
486                            }
487                        } elseif ($allowOverwrite || !isset($output[$key])) {
488                            if (null !== $tag) {
489                                $output[$key] = new TaggedValue($tag, $value);
490                            } else {
491                                $output[$key] = $value;
492                            }
493                        } elseif (isset($output[$key])) {
494                            throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), self::$parsedLineNumber + 1, $mapping);
495                        }
496                        break;
497                    case '{':
498                        // nested mapping
499                        $value = self::parseMapping($mapping, $flags, $i, $references);
500                        // Spec: Keys MUST be unique; first one wins.
501                        // Parser cannot abort this mapping earlier, since lines
502                        // are processed sequentially.
503                        // But overwriting is allowed when a merge node is used in current block.
504                        if ('<<' === $key) {
505                            $output += $value;
506                        } elseif ($allowOverwrite || !isset($output[$key])) {
507                            if (null !== $tag) {
508                                $output[$key] = new TaggedValue($tag, $value);
509                            } else {
510                                $output[$key] = $value;
511                            }
512                        } elseif (isset($output[$key])) {
513                            throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), self::$parsedLineNumber + 1, $mapping);
514                        }
515                        break;
516                    default:
517                        $value = self::parseScalar($mapping, $flags, [',', '}', "\n"], $i, null === $tag, $references);
518                        // Spec: Keys MUST be unique; first one wins.
519                        // Parser cannot abort this mapping earlier, since lines
520                        // are processed sequentially.
521                        // But overwriting is allowed when a merge node is used in current block.
522                        if ('<<' === $key) {
523                            $output += $value;
524                        } elseif ($allowOverwrite || !isset($output[$key])) {
525                            if (null !== $tag) {
526                                $output[$key] = new TaggedValue($tag, $value);
527                            } else {
528                                $output[$key] = $value;
529                            }
530                        } elseif (isset($output[$key])) {
531                            throw new ParseException(sprintf('Duplicate key "%s" detected.', $key), self::$parsedLineNumber + 1, $mapping);
532                        }
533                        --$i;
534                }
535                ++$i;
536
537                continue 2;
538            }
539        }
540
541        throw new ParseException(sprintf('Malformed inline YAML string: "%s".', $mapping), self::$parsedLineNumber + 1, null, self::$parsedFilename);
542    }
543
544    /**
545     * Evaluates scalars and replaces magic values.
546     *
547     * @return mixed The evaluated YAML string
548     *
549     * @throws ParseException when object parsing support was disabled and the parser detected a PHP object or when a reference could not be resolved
550     */
551    private static function evaluateScalar(string $scalar, int $flags, array $references = [])
552    {
553        $scalar = trim($scalar);
554
555        if ('*' === ($scalar[0] ?? '')) {
556            if (false !== $pos = strpos($scalar, '#')) {
557                $value = substr($scalar, 1, $pos - 2);
558            } else {
559                $value = substr($scalar, 1);
560            }
561
562            // an unquoted *
563            if (false === $value || '' === $value) {
564                throw new ParseException('A reference must contain at least one character.', self::$parsedLineNumber + 1, $value, self::$parsedFilename);
565            }
566
567            if (!\array_key_exists($value, $references)) {
568                throw new ParseException(sprintf('Reference "%s" does not exist.', $value), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
569            }
570
571            return $references[$value];
572        }
573
574        $scalarLower = strtolower($scalar);
575
576        switch (true) {
577            case 'null' === $scalarLower:
578            case '' === $scalar:
579            case '~' === $scalar:
580                return null;
581            case 'true' === $scalarLower:
582                return true;
583            case 'false' === $scalarLower:
584                return false;
585            case '!' === $scalar[0]:
586                switch (true) {
587                    case 0 === strncmp($scalar, '!!str ', 6):
588                        return (string) substr($scalar, 6);
589                    case 0 === strncmp($scalar, '! ', 2):
590                        return substr($scalar, 2);
591                    case 0 === strncmp($scalar, '!php/object', 11):
592                        if (self::$objectSupport) {
593                            if (!isset($scalar[12])) {
594                                trigger_deprecation('symfony/yaml', '5.1', 'Using the !php/object tag without a value is deprecated.');
595
596                                return false;
597                            }
598
599                            return unserialize(self::parseScalar(substr($scalar, 12)));
600                        }
601
602                        if (self::$exceptionOnInvalidType) {
603                            throw new ParseException('Object support when parsing a YAML file has been disabled.', self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
604                        }
605
606                        return null;
607                    case 0 === strncmp($scalar, '!php/const', 10):
608                        if (self::$constantSupport) {
609                            if (!isset($scalar[11])) {
610                                trigger_deprecation('symfony/yaml', '5.1', 'Using the !php/const tag without a value is deprecated.');
611
612                                return '';
613                            }
614
615                            $i = 0;
616                            if (\defined($const = self::parseScalar(substr($scalar, 11), 0, null, $i, false))) {
617                                return \constant($const);
618                            }
619
620                            throw new ParseException(sprintf('The constant "%s" is not defined.', $const), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
621                        }
622                        if (self::$exceptionOnInvalidType) {
623                            throw new ParseException(sprintf('The string "%s" could not be parsed as a constant. Did you forget to pass the "Yaml::PARSE_CONSTANT" flag to the parser?', $scalar), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
624                        }
625
626                        return null;
627                    case 0 === strncmp($scalar, '!!float ', 8):
628                        return (float) substr($scalar, 8);
629                    case 0 === strncmp($scalar, '!!binary ', 9):
630                        return self::evaluateBinaryScalar(substr($scalar, 9));
631                    default:
632                        throw new ParseException(sprintf('The string "%s" could not be parsed as it uses an unsupported built-in tag.', $scalar), self::$parsedLineNumber, $scalar, self::$parsedFilename);
633                }
634            case preg_match('/^(?:\+|-)?0o(?P<value>[0-7_]++)$/', $scalar, $matches):
635                $value = str_replace('_', '', $matches['value']);
636
637                if ('-' === $scalar[0]) {
638                    return -octdec($value);
639                } else {
640                    return octdec($value);
641                }
642
643            // Optimize for returning strings.
644            // no break
645            case \in_array($scalar[0], ['+', '-', '.'], true) || is_numeric($scalar[0]):
646                if (Parser::preg_match('{^[+-]?[0-9][0-9_]*$}', $scalar)) {
647                    $scalar = str_replace('_', '', (string) $scalar);
648                }
649
650                switch (true) {
651                    case ctype_digit($scalar):
652                        if ('0' === $scalar[0] && '0' !== $scalar) {
653                            trigger_deprecation('symfony/yaml', '5.1', 'Support for parsing numbers prefixed with 0 as octal numbers. They will be parsed as strings as of 6.0.');
654
655                            return octdec(preg_replace('/[^0-7]/', '', $scalar));
656                        }
657
658                        $cast = (int) $scalar;
659
660                        return ($scalar === (string) $cast) ? $cast : $scalar;
661                    case '-' === $scalar[0] && ctype_digit(substr($scalar, 1)):
662                        if ('0' === $scalar[1] && '-0' !== $scalar) {
663                            trigger_deprecation('symfony/yaml', '5.1', 'Support for parsing numbers prefixed with 0 as octal numbers. They will be parsed as strings as of 6.0.');
664
665                            return -octdec(preg_replace('/[^0-7]/', '', substr($scalar, 1)));
666                        }
667
668                        $cast = (int) $scalar;
669
670                        return ($scalar === (string) $cast) ? $cast : $scalar;
671                    case is_numeric($scalar):
672                    case Parser::preg_match(self::getHexRegex(), $scalar):
673                        $scalar = str_replace('_', '', $scalar);
674
675                        return '0x' === $scalar[0].$scalar[1] ? hexdec($scalar) : (float) $scalar;
676                    case '.inf' === $scalarLower:
677                    case '.nan' === $scalarLower:
678                        return -log(0);
679                    case '-.inf' === $scalarLower:
680                        return log(0);
681                    case Parser::preg_match('/^(-|\+)?[0-9][0-9_]*(\.[0-9_]+)?$/', $scalar):
682                        return (float) str_replace('_', '', $scalar);
683                    case Parser::preg_match(self::getTimestampRegex(), $scalar):
684                        if (Yaml::PARSE_DATETIME & $flags) {
685                            // When no timezone is provided in the parsed date, YAML spec says we must assume UTC.
686                            return new \DateTime($scalar, new \DateTimeZone('UTC'));
687                        }
688
689                        $timeZone = date_default_timezone_get();
690                        date_default_timezone_set('UTC');
691                        $time = strtotime($scalar);
692                        date_default_timezone_set($timeZone);
693
694                        return $time;
695                }
696        }
697
698        return (string) $scalar;
699    }
700
701    private static function parseTag(string $value, int &$i, int $flags): ?string
702    {
703        if ('!' !== $value[$i]) {
704            return null;
705        }
706
707        $tagLength = strcspn($value, " \t\n[]{},", $i + 1);
708        $tag = substr($value, $i + 1, $tagLength);
709
710        $nextOffset = $i + $tagLength + 1;
711        $nextOffset += strspn($value, ' ', $nextOffset);
712
713        if ('' === $tag && (!isset($value[$nextOffset]) || \in_array($value[$nextOffset], [']', '}', ','], true))) {
714            throw new ParseException(sprintf('Using the unquoted scalar value "!" is not supported. You must quote it.', $value), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
715        }
716
717        // Is followed by a scalar and is a built-in tag
718        if ('' !== $tag && (!isset($value[$nextOffset]) || !\in_array($value[$nextOffset], ['[', '{'], true)) && ('!' === $tag[0] || 'str' === $tag || 'php/const' === $tag || 'php/object' === $tag)) {
719            // Manage in {@link self::evaluateScalar()}
720            return null;
721        }
722
723        $i = $nextOffset;
724
725        // Built-in tags
726        if ('' !== $tag && '!' === $tag[0]) {
727            throw new ParseException(sprintf('The built-in tag "!%s" is not implemented.', $tag), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
728        }
729
730        if ('' !== $tag && !isset($value[$i])) {
731            throw new ParseException(sprintf('Missing value for tag "%s".', $tag), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
732        }
733
734        if ('' === $tag || Yaml::PARSE_CUSTOM_TAGS & $flags) {
735            return $tag;
736        }
737
738        throw new ParseException(sprintf('Tags support is not enabled. Enable the "Yaml::PARSE_CUSTOM_TAGS" flag to use "!%s".', $tag), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
739    }
740
741    public static function evaluateBinaryScalar(string $scalar): string
742    {
743        $parsedBinaryData = self::parseScalar(preg_replace('/\s/', '', $scalar));
744
745        if (0 !== (\strlen($parsedBinaryData) % 4)) {
746            throw new ParseException(sprintf('The normalized base64 encoded data (data without whitespace characters) length must be a multiple of four (%d bytes given).', \strlen($parsedBinaryData)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
747        }
748
749        if (!Parser::preg_match('#^[A-Z0-9+/]+={0,2}$#i', $parsedBinaryData)) {
750            throw new ParseException(sprintf('The base64 encoded data (%s) contains invalid characters.', $parsedBinaryData), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
751        }
752
753        return base64_decode($parsedBinaryData, true);
754    }
755
756    private static function isBinaryString(string $value): bool
757    {
758        return !preg_match('//u', $value) || preg_match('/[^\x00\x07-\x0d\x1B\x20-\xff]/', $value);
759    }
760
761    /**
762     * Gets a regex that matches a YAML date.
763     *
764     * @return string The regular expression
765     *
766     * @see http://www.yaml.org/spec/1.2/spec.html#id2761573
767     */
768    private static function getTimestampRegex(): string
769    {
770        return <<<EOF
771        ~^
772        (?P<year>[0-9][0-9][0-9][0-9])
773        -(?P<month>[0-9][0-9]?)
774        -(?P<day>[0-9][0-9]?)
775        (?:(?:[Tt]|[ \t]+)
776        (?P<hour>[0-9][0-9]?)
777        :(?P<minute>[0-9][0-9])
778        :(?P<second>[0-9][0-9])
779        (?:\.(?P<fraction>[0-9]*))?
780        (?:[ \t]*(?P<tz>Z|(?P<tz_sign>[-+])(?P<tz_hour>[0-9][0-9]?)
781        (?::(?P<tz_minute>[0-9][0-9]))?))?)?
782        $~x
783EOF;
784    }
785
786    /**
787     * Gets a regex that matches a YAML number in hexadecimal notation.
788     */
789    private static function getHexRegex(): string
790    {
791        return '~^0x[0-9a-f_]++$~i';
792    }
793}
794