Stringy\Stringy

Complexity

Total Complexity

173

Size/Duplication

Total Lines	1827
Duplicated Lines	11.77 %

Coupling/Cohesion

Components	1
Dependencies	3

Test Coverage

Coverage

99.8%

Importance

Changes	70
Bugs	9	Features	27

93 Methods

Rating	Name	Duplication	Size	Complexity
C	__construct()	0	35	7
A	__toString()	0	4	1
A	append()	0	4	1
A	create()	0	4	1
A	between()	0	15	3
A	indexOf()	0	4	1
A	substr()	0	10	2
A	length()	0	4	1
A	collapseWhitespace()	0	4	1
A	trim()	10	10	2
A	regexReplace()	0	14	2
A	containsAll()	15	15	4
A	contains()	0	10	2
A	containsAny()	15	15	4
A	count()	0	4	1
A	countSubstr()	0	11	2
A	dasherize()	0	4	1
A	delimit()	0	12	1
A	ensureLeft()	10	10	2
A	ensureRight()	10	10	2
A	endsWith()	4	19	2
A	first()	12	12	2
A	getEncoding()	0	4	1
A	getIterator()	0	4	1
A	chars()	0	12	2
A	at()	0	4	1
A	hasLowerCase()	0	4	1
A	matchesPattern()	0	8	2
A	hasUpperCase()	0	4	1
A	htmlDecode()	0	6	1
A	htmlEncode()	0	6	1
A	humanize()	0	6	1
A	upperCaseFirst()	14	14	1
A	indexOfLast()	0	4	1
A	insert()	17	17	2
A	isAlpha()	0	4	1
A	isAlphanumeric()	0	4	1
A	isBlank()	0	4	1
A	isHexadecimal()	0	4	1
A	isJson()	0	14	3
A	isLowerCase()	0	8	2
A	isSerialized()	0	17	4
A	isUpperCase()	0	4	1
A	last()	12	12	2
A	lines()	3	10	2
A	longestCommonPrefix()	0	18	3
A	longestCommonSuffix()	0	18	3
C	longestCommonSubstring()	0	44	7
A	offsetExists()	0	12	2
A	offsetGet()	0	16	4
A	offsetSet()	0	5	1
A	offsetUnset()	0	5	1
B	applyPadding()	0	37	3
A	prepend()	0	4	1
A	removeLeft()	12	12	2
A	removeRight()	12	12	2
A	repeat()	0	6	1
A	replace()	0	4	1
A	replaceBeginning()	0	6	1
A	replaceEnding()	0	6	1
A	reverse()	0	6	1
B	safeTruncate()	0	25	3
A	shuffle()	0	6	1
A	slugify()	0	6	1
A	escape()	0	10	1
A	removeXss()	0	12	2
A	removeHtml()	0	6	1
B	slice()	0	16	5
C	split()	3	33	7
A	surround()	0	6	1
A	swapCase()	0	21	2
A	tidy()	0	6	1
A	titleize()	0	21	3
A	toLowerCase()	0	6	1
A	isBase64()	0	12	3
A	toAscii()	0	6	1
A	toBoolean()	0	22	3
A	toSpaces()	7	7	1
A	toTabs()	7	7	1
A	toTitleCase()	0	7	1
A	toUpperCase()	0	6	1
A	trimLeft()	10	10	2
A	trimRight()	10	10	2
A	truncate()	16	16	2
A	underscored()	0	4	1
A	upperCamelize()	0	4	1
B	camelize()	0	28	2
A	lowerCaseFirst()	12	12	1
A	padLeft()	0	4	1
A	padRight()	0	4	1
A	padBoth()	0	6	1
A	startsWith()	4	15	2
A	pad()	0	17	4

<?php

namespace Stringy;

use voku\helper\AntiXSS;
use voku\helper\URLify;
use voku\helper\UTF8;

/**
 * Class Stringy
 *
 * @package Stringy
 */
class Stringy implements \Countable, \IteratorAggregate, \ArrayAccess
{
  /**
   * An instance's string.
   *
   * @var string
   */
  protected $str;

  /**
   * The string's encoding, which should be one of the mbstring module's
   * supported encodings.
   *
   * @var string
   */
  protected $encoding;

  /**
   * Initializes a Stringy object and assigns both str and encoding properties
   * the supplied values. $str is cast to a string prior to assignment, and if
   * $encoding is not specified, it defaults to mb_internal_encoding(). Throws
   * an InvalidArgumentException if the first argument is an array or object
   * without a __toString method.
   *
   * @param  mixed  $str      Value to modify, after being cast to string
   * @param  string $encoding The character encoding
   *
   * @throws \InvalidArgumentException if an array or object without a
   *         __toString method is passed as the first argument
   */
  public function __construct($str = '', $encoding = null)
  {
    if (is_array($str)) {
      throw new \InvalidArgumentException(
          'Passed value cannot be an array'
      );
    } elseif (is_object($str) && !method_exists($str, '__toString')) {
      throw new \InvalidArgumentException(
          'Passed object must have a __toString method'
      );
    }


    // don't throw a notice on PHP 5.3
    if (!defined('ENT_SUBSTITUTE')) {
      define('ENT_SUBSTITUTE', 8);
    }

    // init
    UTF8::checkForSupport();
    $this->str = (string) $str;

    if ($encoding) {

The expression $encoding of type string|null is loosely compared to true; this is ambiguous if the string can be empty. You might want to explicitly use !== null instead.

      $this->encoding = $encoding;
    } else {
      UTF8::mbstring_loaded();
      $this->encoding = mb_internal_encoding();
    }

    if ($encoding) {

The expression $encoding of type string|null is loosely compared to true; this is ambiguous if the string can be empty. You might want to explicitly use !== null instead.

      $this->encoding = $encoding;
    } else {
      $this->encoding = mb_internal_encoding();
    }
  }

  /**
   * Returns the value in $str.
   *
   * @return string The current value of the $str property
   */
  public function __toString()
  {
    return $this->str;
  }

  /**
   * Returns a new string with $string appended.
   *
   * @param  string $string The string to append
   *
   * @return Stringy Object with appended $string
   */
  public function append($string)
  {
    return static::create($this->str . $string, $this->encoding);
  }

  /**
   * Creates a Stringy object and assigns both str and encoding properties
   * the supplied values. $str is cast to a string prior to assignment, and if
   * $encoding is not specified, it defaults to mb_internal_encoding(). It
   * then returns the initialized object. Throws an InvalidArgumentException
   * if the first argument is an array or object without a __toString method.
   *
   * @param  mixed  $str      Value to modify, after being cast to string
   * @param  string $encoding The character encoding
   *
   * @return Stringy A Stringy object
   * @throws \InvalidArgumentException if an array or object without a
   *         __toString method is passed as the first argument
   */
  public static function create($str = '', $encoding = null)
  {
    return new static($str, $encoding);
  }

  /**
   * Returns the substring between $start and $end, if found, or an empty
   * string. An optional offset may be supplied from which to begin the
   * search for the start string.
   *
   * @param  string $start  Delimiter marking the start of the substring
   * @param  string $end    Delimiter marketing the end of the substring
   * @param  int    $offset Index from which to begin the search
   *
   * @return Stringy Object whose $str has been converted to an URL slug
   */
  public function between($start, $end, $offset = 0)
  {
    $startIndex = $this->indexOf($start, $offset);
    if ($startIndex === false) {
      return static::create('', $this->encoding);
    }

    $substrIndex = $startIndex + UTF8::strlen($start, $this->encoding);
    $endIndex = $this->indexOf($end, $substrIndex);
    if ($endIndex === false) {
      return static::create('', $this->encoding);
    }

    return $this->substr($substrIndex, $endIndex - $substrIndex);
  }

  /**
   * Returns the index of the first occurrence of $needle in the string,
   * and false if not found. Accepts an optional offset from which to begin
   * the search.
   *
   * @param  string $needle Substring to look for
   * @param  int    $offset Offset from which to search
   *
   * @return int|bool The occurrence's index if found, otherwise false
   */
  public function indexOf($needle, $offset = 0)
  {
    return UTF8::strpos($this->str, (string) $needle, (int) $offset, $this->encoding);
  }

  /**
   * Returns the substring beginning at $start with the specified $length.
   * It differs from the UTF8::substr() function in that providing a $length of
   * null will return the rest of the string, rather than an empty string.
   *
   * @param  int $start  Position of the first character to use
   * @param  int $length Maximum number of characters used
   *
   * @return Stringy Object with its $str being the substring
   */
  public function substr($start, $length = null)
  {
    if ($length === null) {
      $length = $this->length();
    }

    $str = UTF8::substr($this->str, $start, $length, $this->encoding);

It seems like $length defined by $this->length() on line 176 can also be of type boolean; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

    return static::create($str, $this->encoding);
  }

  /**
   * Returns the length of the string.
   *
   * @return int The number of characters in $str given the encoding
   */
  public function length()
  {
    return UTF8::strlen($this->str, $this->encoding);
  }

  /**
   * Trims the string and replaces consecutive whitespace characters with a
   * single space. This includes tabs and newline characters, as well as
   * multibyte whitespace such as the thin space and ideographic space.
   *
   * @return Stringy Object with a trimmed $str and condensed whitespace
   */
  public function collapseWhitespace()
  {
    return $this->regexReplace('[[:space:]]+', ' ')->trim();
  }

  /**
   * Returns a string with whitespace removed from the start and end of the
   * string. Supports the removal of unicode whitespace. Accepts an optional
   * string of characters to strip instead of the defaults.
   *
   * @param  string $chars Optional string of characters to strip
   *
   * @return Stringy Object with a trimmed $str
   */
  public function trim($chars = null)

This method seems to be duplicated in your project.

  {
    if (!$chars) {

The expression $chars of type string|null is loosely compared to false; this is ambiguous if the string can be empty. You might want to explicitly use === null instead.

      $chars = '[:space:]';
    } else {
      $chars = preg_quote($chars, '/');
    }

    return $this->regexReplace("^[$chars]+|[$chars]+\$", '');
  }

  /**
   * Replaces all occurrences of $pattern in $str by $replacement.
   *
   * @param  string $pattern     The regular expression pattern
   * @param  string $replacement The string to replace with
   * @param  string $options     Matching conditions to be used
   *
   * @return Stringy Object with the result2ing $str after the replacements
   */
  public function regexReplace($pattern, $replacement, $options = '')
  {
    if ($options === 'msr') {
      $options = 'ms';
    }

    $str = preg_replace(
        '/' . $pattern . '/u' . $options,
        $replacement,
        $this->str
    );

    return static::create($str, $this->encoding);
  }

  /**
   * Returns true if the string contains all $needles, false otherwise. By
   * default the comparison is case-sensitive, but can be made insensitive by
   * setting $caseSensitive to false.
   *
   * @param  array $needles       SubStrings to look for
   * @param  bool  $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return bool   Whether or not $str contains $needle
   */
  public function containsAll($needles, $caseSensitive = true)

This method seems to be duplicated in your project.

  {
    /** @noinspection IsEmptyFunctionUsageInspection */
    if (empty($needles)) {
      return false;
    }

    foreach ($needles as $needle) {
      if (!$this->contains($needle, $caseSensitive)) {
        return false;
      }
    }

    return true;
  }

  /**
   * Returns true if the string contains $needle, false otherwise. By default
   * the comparison is case-sensitive, but can be made insensitive by setting
   * $caseSensitive to false.
   *
   * @param  string $needle        Substring to look for
   * @param  bool   $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return bool   Whether or not $str contains $needle
   */
  public function contains($needle, $caseSensitive = true)
  {
    $encoding = $this->encoding;

    if ($caseSensitive) {
      return (UTF8::strpos($this->str, $needle, 0, $encoding) !== false);
    } else {
      return (UTF8::stripos($this->str, $needle, 0, $encoding) !== false);
    }
  }

  /**
   * Returns true if the string contains any $needles, false otherwise. By
   * default the comparison is case-sensitive, but can be made insensitive by
   * setting $caseSensitive to false.
   *
   * @param  array $needles       SubStrings to look for
   * @param  bool  $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return bool   Whether or not $str contains $needle
   */
  public function containsAny($needles, $caseSensitive = true)

This method seems to be duplicated in your project.

  {
    /** @noinspection IsEmptyFunctionUsageInspection */
    if (empty($needles)) {
      return false;
    }

    foreach ($needles as $needle) {
      if ($this->contains($needle, $caseSensitive)) {
        return true;
      }
    }

    return false;
  }

  /**
   * Returns the length of the string, implementing the countable interface.
   *
   * @return int The number of characters in the string, given the encoding
   */
  public function count()
  {
    return $this->length();

The expression $this->length(); of type integer|boolean adds the type boolean to the return on line 330 which is incompatible with the return type declared by the interface Countable::count of type integer.

  }

  /**
   * Returns the number of occurrences of $substring in the given string.
   * By default, the comparison is case-sensitive, but can be made insensitive
   * by setting $caseSensitive to false.
   *
   * @param  string $substring     The substring to search for
   * @param  bool   $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return int    The number of $substring occurrences
   */
  public function countSubstr($substring, $caseSensitive = true)
  {
    if ($caseSensitive) {
      return UTF8::substr_count($this->str, $substring, $this->encoding);
    }

    $str = UTF8::strtoupper($this->str, $this->encoding);
    $substring = UTF8::strtoupper($substring, $this->encoding);

    return UTF8::substr_count($str, $substring, $this->encoding);
  }

  /**
   * Returns a lowercase and trimmed string separated by dashes. Dashes are
   * inserted before uppercase characters (with the exception of the first
   * character of the string), and in place of spaces as well as underscores.
   *
   * @return Stringy Object with a dasherized $str
   */
  public function dasherize()
  {
    return $this->delimit('-');
  }

  /**
   * Returns a lowercase and trimmed string separated by the given delimiter.
   * Delimiters are inserted before uppercase characters (with the exception
   * of the first character of the string), and in place of spaces, dashes,
   * and underscores. Alpha delimiters are not converted to lowercase.
   *
   * @param  string $delimiter Sequence used to separate parts of the string
   *
   * @return Stringy Object with a delimited $str
   */
  public function delimit($delimiter)
  {
    $str = $this->trim();

    $str = preg_replace('/\B([A-Z])/u', '-\1', $str);

    $str = UTF8::strtolower($str, $this->encoding);

It seems like $str can also be of type array<integer,string>; however, voku\helper\UTF8::strtolower() does only seem to accept string, maybe add an additional type check?

    $str = preg_replace('/[-_\s]+/u', $delimiter, $str);

    return static::create($str, $this->encoding);
  }

  /**
   * Ensures that the string begins with $substring. If it doesn't, it's
   * prepended.
   *
   * @param  string $substring The substring to add if not present
   *
   * @return Stringy Object with its $str prefixed by the $substring
   */
  public function ensureLeft($substring)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if (!$stringy->startsWith($substring)) {
      $stringy->str = $substring . $stringy->str;
    }

    return $stringy;
  }

  /**
   * Returns true if the string begins with $substring, false otherwise. By
   * default, the comparison is case-sensitive, but can be made insensitive
   * by setting $caseSensitive to false.
   *
   * @param  string $substring     The substring to look for
   * @param  bool   $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return bool   Whether or not $str starts with $substring
   */
  public function startsWith($substring, $caseSensitive = true)
  {
    $substringLength = UTF8::strlen($substring, $this->encoding);
    $startOfStr = UTF8::substr(
        $this->str, 0, $substringLength,

It seems like $substringLength defined by \voku\helper\UTF8::strlen($substring, $this->encoding) on line 421 can also be of type boolean; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

        $this->encoding
    );

    if (!$caseSensitive) {

This code seems to be duplicated across your project.

      $substring = UTF8::strtolower($substring, $this->encoding);
      $startOfStr = UTF8::strtolower($startOfStr, $this->encoding);
    }

    return (string) $substring === $startOfStr;
  }

  /**
   * Ensures that the string ends with $substring. If it doesn't, it's
   * appended.
   *
   * @param  string $substring The substring to add if not present
   *
   * @return Stringy Object with its $str suffixed by the $substring
   */
  public function ensureRight($substring)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if (!$stringy->endsWith($substring)) {
      $stringy->str .= $substring;
    }

    return $stringy;
  }

  /**
   * Returns true if the string ends with $substring, false otherwise. By
   * default, the comparison is case-sensitive, but can be made insensitive
   * by setting $caseSensitive to false.
   *
   * @param  string $substring     The substring to look for
   * @param  bool   $caseSensitive Whether or not to enforce case-sensitivity
   *
   * @return bool   Whether or not $str ends with $substring
   */
  public function endsWith($substring, $caseSensitive = true)
  {
    $substringLength = UTF8::strlen($substring, $this->encoding);
    $strLength = $this->length();

    $endOfStr = UTF8::substr(
        $this->str,
        $strLength - $substringLength,
        $substringLength,

It seems like $substringLength defined by \voku\helper\UTF8::strlen($substring, $this->encoding) on line 466 can also be of type boolean; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

        $this->encoding
    );

    if (!$caseSensitive) {

This code seems to be duplicated across your project.

      $substring = UTF8::strtolower($substring, $this->encoding);
      $endOfStr = UTF8::strtolower($endOfStr, $this->encoding);
    }

    return (string) $substring === $endOfStr;
  }

  /**
   * Returns the first $n characters of the string.
   *
   * @param  int $n Number of characters to retrieve from the start
   *
   * @return Stringy Object with its $str being the first $n chars
   */
  public function first($n)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if ($n < 0) {
      $stringy->str = '';
    } else {
      return $stringy->substr(0, $n);
    }

    return $stringy;
  }

  /**
   * Returns the encoding used by the Stringy object.
   *
   * @return string The current value of the $encoding property
   */
  public function getEncoding()
  {
    return $this->encoding;
  }

  /**
   * Returns a new ArrayIterator, thus implementing the IteratorAggregate
   * interface. The ArrayIterator's constructor is passed an array of chars
   * in the multibyte string. This enables the use of foreach with instances
   * of Stringy\Stringy.
   *
   * @return \ArrayIterator An iterator for the characters in the string
   */
  public function getIterator()
  {
    return new \ArrayIterator($this->chars());
  }

  /**
   * Returns an array consisting of the characters in the string.
   *
   * @return array An array of string chars
   */
  public function chars()
  {
    // init
    $chars = array();
    $l = $this->length();

    for ($i = 0; $i < $l; $i++) {
      $chars[] = $this->at($i)->str;
    }

    return $chars;
  }

  /**
   * Returns the character at $index, with indexes starting at 0.
   *
   * @param  int $index Position of the character
   *
   * @return Stringy The character at $index
   */
  public function at($index)
  {
    return $this->substr($index, 1);
  }

  /**
   * Returns true if the string contains a lower case char, false
   * otherwise.
   *
   * @return bool Whether or not the string contains a lower case character.
   */
  public function hasLowerCase()
  {
    return $this->matchesPattern('.*[[:lower:]]');
  }

  /**
   * Returns true if $str matches the supplied pattern, false otherwise.
   *
   * @param  string $pattern Regex pattern to match against
   *
   * @return bool   Whether or not $str matches the pattern
   */
  private function matchesPattern($pattern)
  {
    if (preg_match('/' . $pattern . '/u', $this->str)) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Returns true if the string contains an upper case char, false
   * otherwise.
   *
   * @return bool Whether or not the string contains an upper case character.
   */
  public function hasUpperCase()
  {
    return $this->matchesPattern('.*[[:upper:]]');
  }

  /**
   * Convert all HTML entities to their applicable characters.
   *
   * @param  int|null $flags Optional flags
   *
   * @return Stringy  Object with the resulting $str after being html decoded.
   */
  public function htmlDecode($flags = ENT_COMPAT)
  {
    $str = UTF8::html_entity_decode($this->str, $flags, $this->encoding);

    return static::create($str, $this->encoding);
  }

  /**
   * Convert all applicable characters to HTML entities.
   *
   * @param  int|null $flags Optional flags
   *
   * @return Stringy  Object with the resulting $str after being html encoded.
   */
  public function htmlEncode($flags = ENT_COMPAT)
  {
    $str = UTF8::htmlentities($this->str, $flags, $this->encoding);

    return static::create($str, $this->encoding);
  }

  /**
   * Capitalizes the first word of the string, replaces underscores with
   * spaces, and strips '_id'.
   *
   * @return Stringy Object with a humanized $str
   */
  public function humanize()
  {
    $str = UTF8::str_replace(array('_id', '_'), array('', ' '), $this->str);

    return static::create($str, $this->encoding)->trim()->upperCaseFirst();
  }

  /**
   * Converts the first character of the supplied string to upper case.
   *
   * @return Stringy Object with the first character of $str being upper case
   */
  public function upperCaseFirst()

This method seems to be duplicated in your project.

  {
    $first = UTF8::substr($this->str, 0, 1, $this->encoding);
    $rest = UTF8::substr(
        $this->str,
        1,
        $this->length() - 1,
        $this->encoding
    );

    $str = UTF8::strtoupper($first, $this->encoding) . $rest;

    return static::create($str, $this->encoding);
  }

  /**
   * Returns the index of the last occurrence of $needle in the string,
   * and false if not found. Accepts an optional offset from which to begin
   * the search. Offsets may be negative to count from the last character
   * in the string.
   *
   * @param  string $needle Substring to look for
   * @param  int    $offset Offset from which to search
   *
   * @return int|bool The last occurrence's index if found, otherwise false
   */
  public function indexOfLast($needle, $offset = 0)
  {
    return UTF8::strrpos($this->str, (string) $needle, (int) $offset, $this->encoding);

$this->encoding is of type string, but the function expects a boolean.

  }

  /**
   * Inserts $substring into the string at the $index provided.
   *
   * @param  string $substring String to be inserted
   * @param  int    $index     The index at which to insert the substring
   *
   * @return Stringy Object with the resulting $str after the insertion
   */
  public function insert($substring, $index)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);
    if ($index > $stringy->length()) {
      return $stringy;
    }

    $start = UTF8::substr($stringy->str, 0, $index, $stringy->encoding);
    $end = UTF8::substr(
        $stringy->str, $index, $stringy->length(),

It seems like $stringy->length() targeting Stringy\Stringy::length() can also be of type boolean; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

        $stringy->encoding
    );

    $stringy->str = $start . $substring . $end;

    return $stringy;
  }

  /**
   * Returns true if the string contains only alphabetic chars, false
   * otherwise.
   *
   * @return bool Whether or not $str contains only alphabetic chars
   */
  public function isAlpha()
  {
    return $this->matchesPattern('^[[:alpha:]]*$');
  }

  /**
   * Returns true if the string contains only alphabetic and numeric chars,
   * false otherwise.
   *
   * @return bool Whether or not $str contains only alphanumeric chars
   */
  public function isAlphanumeric()
  {
    return $this->matchesPattern('^[[:alnum:]]*$');
  }

  /**
   * Returns true if the string contains only whitespace chars, false
   * otherwise.
   *
   * @return bool Whether or not $str contains only whitespace characters
   */
  public function isBlank()
  {
    return $this->matchesPattern('^[[:space:]]*$');
  }

  /**
   * Returns true if the string contains only hexadecimal chars, false
   * otherwise.
   *
   * @return bool Whether or not $str contains only hexadecimal chars
   */
  public function isHexadecimal()
  {
    return $this->matchesPattern('^[[:xdigit:]]*$');
  }

  /**
   * Returns true if the string is JSON, false otherwise. Unlike json_decode
   * in PHP 5.x, this method is consistent with PHP 7 and other JSON parsers,
   * in that an empty string is not considered valid JSON.
   *
   * @return bool Whether or not $str is JSON
   */
  public function isJson()
  {
    if (!isset($this->str[0])) {
      return false;
    }

    json_decode($this->str);

    if (json_last_error() === JSON_ERROR_NONE) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Returns true if the string contains only lower case chars, false
   * otherwise.
   *
   * @return bool Whether or not $str contains only lower case characters
   */
  public function isLowerCase()
  {
    if ($this->matchesPattern('^[[:lower:]]*$')) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Returns true if the string is serialized, false otherwise.
   *
   * @return bool Whether or not $str is serialized
   */
  public function isSerialized()
  {
    if (!isset($this->str[0])) {
      return false;
    }

    /** @noinspection PhpUsageOfSilenceOperatorInspection */
    if (
        $this->str === 'b:0;'
        ||
        @unserialize($this->str) !== false
    ) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Returns true if the string contains only lower case chars, false
   * otherwise.
   *
   * @return bool Whether or not $str contains only lower case characters
   */
  public function isUpperCase()
  {
    return $this->matchesPattern('^[[:upper:]]*$');
  }

  /**
   * Returns the last $n characters of the string.
   *
   * @param  int $n Number of characters to retrieve from the end
   *
   * @return Stringy Object with its $str being the last $n chars
   */
  public function last($n)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if ($n <= 0) {
      $stringy->str = '';
    } else {
      return $stringy->substr(-$n);
    }

    return $stringy;
  }

  /**
   * Splits on newlines and carriage returns, returning an array of Stringy
   * objects corresponding to the lines in the string.
   *
   * @return Stringy[] An array of Stringy objects
   */
  public function lines()
  {
    $array = preg_split('/[\r\n]{1,2}/u', $this->str);
    /** @noinspection CallableInLoopTerminationConditionInspection */
    for ($i = 0; $i < count($array); $i++) {

It seems like you are calling the size function count() as part of the test condition. You might want to compute the size beforehand, and not on each iteration.

This code seems to be duplicated across your project.

      $array[$i] = static::create($array[$i], $this->encoding);
    }

    return $array;
  }

  /**
   * Returns the longest common prefix between the string and $otherStr.
   *
   * @param  string $otherStr Second string for comparison
   *
   * @return Stringy Object with its $str being the longest common prefix
   */
  public function longestCommonPrefix($otherStr)
  {
    $encoding = $this->encoding;
    $maxLength = min($this->length(), UTF8::strlen($otherStr, $encoding));

    $longestCommonPrefix = '';
    for ($i = 0; $i < $maxLength; $i++) {
      $char = UTF8::substr($this->str, $i, 1, $encoding);

      if ($char == UTF8::substr($otherStr, $i, 1, $encoding)) {
        $longestCommonPrefix .= $char;
      } else {
        break;
      }
    }

    return static::create($longestCommonPrefix, $encoding);
  }

  /**
   * Returns the longest common suffix between the string and $otherStr.
   *
   * @param  string $otherStr Second string for comparison
   *
   * @return Stringy Object with its $str being the longest common suffix
   */
  public function longestCommonSuffix($otherStr)
  {
    $encoding = $this->encoding;
    $maxLength = min($this->length(), UTF8::strlen($otherStr, $encoding));

    $longestCommonSuffix = '';
    for ($i = 1; $i <= $maxLength; $i++) {
      $char = UTF8::substr($this->str, -$i, 1, $encoding);

      if ($char == UTF8::substr($otherStr, -$i, 1, $encoding)) {
        $longestCommonSuffix = $char . $longestCommonSuffix;
      } else {
        break;
      }
    }

    return static::create($longestCommonSuffix, $encoding);
  }

  /**
   * Returns the longest common substring between the string and $otherStr.
   * In the case of ties, it returns that which occurs first.
   *
   * @param  string $otherStr Second string for comparison
   *
   * @return Stringy Object with its $str being the longest common substring
   */
  public function longestCommonSubstring($otherStr)
  {
    // Uses dynamic programming to solve
    // http://en.wikipedia.org/wiki/Longest_common_substring_problem
    $encoding = $this->encoding;
    $stringy = static::create($this->str, $encoding);
    $strLength = $stringy->length();
    $otherLength = UTF8::strlen($otherStr, $encoding);

    // Return if either string is empty
    if ($strLength == 0 || $otherLength == 0) {
      $stringy->str = '';

      return $stringy;
    }

    $len = 0;
    $end = 0;
    $table = array_fill(
        0, $strLength + 1,
        array_fill(0, $otherLength + 1, 0)
    );

    for ($i = 1; $i <= $strLength; $i++) {
      for ($j = 1; $j <= $otherLength; $j++) {
        $strChar = UTF8::substr($stringy->str, $i - 1, 1, $encoding);
        $otherChar = UTF8::substr($otherStr, $j - 1, 1, $encoding);

        if ($strChar == $otherChar) {
          $table[$i][$j] = $table[$i - 1][$j - 1] + 1;
          if ($table[$i][$j] > $len) {
            $len = $table[$i][$j];
            $end = $i;
          }
        } else {
          $table[$i][$j] = 0;
        }
      }
    }

    $stringy->str = UTF8::substr($stringy->str, $end - $len, $len, $encoding);

    return $stringy;
  }

  /**
   * Returns whether or not a character exists at an index. Offsets may be
   * negative to count from the last character in the string. Implements
   * part of the ArrayAccess interface.
   *
   * @param  mixed $offset The index to check
   *
   * @return boolean Whether or not the index exists
   */
  public function offsetExists($offset)
  {
    // init
    $length = $this->length();
    $offset = (int) $offset;

    if ($offset >= 0) {
      return ($length > $offset);
    }

    return ($length >= abs($offset));
  }

  /**
   * Returns the character at the given index. Offsets may be negative to
   * count from the last character in the string. Implements part of the
   * ArrayAccess interface, and throws an OutOfBoundsException if the index
   * does not exist.
   *
   * @param  mixed $offset The index from which to retrieve the char
   *
   * @return string                 The character at the specified index
   * @throws \OutOfBoundsException If the positive or negative offset does
   *                               not exist
   */
  public function offsetGet($offset)
  {
    // init
    $offset = (int)$offset;
    $length = $this->length();

    if (
        ($offset >= 0 && $length <= $offset)
        ||
        $length < abs($offset)
    ) {
      throw new \OutOfBoundsException('No character exists at the index');
    }

    return UTF8::substr($this->str, $offset, 1, $this->encoding);
  }

  /**
   * Implements part of the ArrayAccess interface, but throws an exception
   * when called. This maintains the immutability of Stringy objects.
   *
   * @param  mixed $offset The index of the character
   * @param  mixed $value  Value to set
   *
   * @throws \Exception When called
   */
  public function offsetSet($offset, $value)
  {
    // Stringy is immutable, cannot directly set char
    throw new \Exception('Stringy object is immutable, cannot modify char');
  }

  /**
   * Implements part of the ArrayAccess interface, but throws an exception
   * when called. This maintains the immutability of Stringy objects.
   *
   * @param  mixed $offset The index of the character
   *
   * @throws \Exception When called
   */
  public function offsetUnset($offset)
  {
    // Don't allow directly modifying the string
    throw new \Exception('Stringy object is immutable, cannot unset char');
  }

  /**
   * Pads the string to a given length with $padStr. If length is less than
   * or equal to the length of the string, no padding takes places. The
   * default string used for padding is a space, and the default type (one of
   * 'left', 'right', 'both') is 'right'. Throws an InvalidArgumentException
   * if $padType isn't one of those 3 values.
   *
   * @param  int    $length  Desired string length after padding
   * @param  string $padStr  String used to pad, defaults to space
   * @param  string $padType One of 'left', 'right', 'both'
   *
   * @return Stringy Object with a padded $str
   * @throws \InvalidArgumentException If $padType isn't one of 'right', 'left' or 'both'
   */
  public function pad($length, $padStr = ' ', $padType = 'right')
  {
    if (!in_array($padType, array('left', 'right', 'both'), true)) {
      throw new \InvalidArgumentException(
          'Pad expects $padType ' . "to be one of 'left', 'right' or 'both'"
      );
    }

    switch ($padType) {
      case 'left':
        return $this->padLeft($length, $padStr);
      case 'right':
        return $this->padRight($length, $padStr);
      default:
        return $this->padBoth($length, $padStr);
    }
  }

  /**
   * Returns a new string of a given length such that the beginning of the
   * string is padded. Alias for pad() with a $padType of 'left'.
   *
   * @param  int    $length Desired string length after padding
   * @param  string $padStr String used to pad, defaults to space
   *
   * @return Stringy String with left padding
   */
  public function padLeft($length, $padStr = ' ')
  {
    return $this->applyPadding($length - $this->length(), 0, $padStr);
  }

  /**
   * Adds the specified amount of left and right padding to the given string.
   * The default character used is a space.
   *
   * @param  int    $left   Length of left padding
   * @param  int    $right  Length of right padding
   * @param  string $padStr String used to pad
   *
   * @return Stringy String with padding applied
   */
  private function applyPadding($left = 0, $right = 0, $padStr = ' ')
  {
    $stringy = static::create($this->str, $this->encoding);

    $length = UTF8::strlen($padStr, $stringy->encoding);

    $strLength = $stringy->length();
    $paddedLength = $strLength + $left + $right;

    if (!$length || $paddedLength <= $strLength) {
      return $stringy;
    }

    $leftPadding = UTF8::substr(
        UTF8::str_repeat(
            $padStr,
            ceil($left / $length)
        ),
        0,
        $left,
        $stringy->encoding
    );

    $rightPadding = UTF8::substr(
        UTF8::str_repeat(
            $padStr,
            ceil($right / $length)
        ),
        0,
        $right,
        $stringy->encoding
    );

    $stringy->str = $leftPadding . $stringy->str . $rightPadding;

    return $stringy;
  }

  /**
   * Returns a new string of a given length such that the end of the string
   * is padded. Alias for pad() with a $padType of 'right'.
   *
   * @param  int    $length Desired string length after padding
   * @param  string $padStr String used to pad, defaults to space
   *
   * @return Stringy String with right padding
   */
  public function padRight($length, $padStr = ' ')
  {
    return $this->applyPadding(0, $length - $this->length(), $padStr);
  }

  /**
   * Returns a new string of a given length such that both sides of the
   * string are padded. Alias for pad() with a $padType of 'both'.
   *
   * @param  int    $length Desired string length after padding
   * @param  string $padStr String used to pad, defaults to space
   *
   * @return Stringy String with padding applied
   */
  public function padBoth($length, $padStr = ' ')
  {
    $padding = $length - $this->length();

    return $this->applyPadding(floor($padding / 2), ceil($padding / 2), $padStr);
  }

  /**
   * Returns a new string starting with $string.
   *
   * @param  string $string The string to append
   *
   * @return Stringy Object with appended $string
   */
  public function prepend($string)
  {
    return static::create($string . $this->str, $this->encoding);
  }

  /**
   * Returns a new string with the prefix $substring removed, if present.
   *
   * @param  string $substring The prefix to remove
   *
   * @return Stringy Object having a $str without the prefix $substring
   */
  public function removeLeft($substring)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if ($stringy->startsWith($substring)) {
      $substringLength = UTF8::strlen($substring, $stringy->encoding);

      return $stringy->substr($substringLength);

It seems like $substringLength defined by \voku\helper\UTF8::strlen($substring, $stringy->encoding) on line 1183 can also be of type boolean; however, Stringy\Stringy::substr() does only seem to accept integer, maybe add an additional type check?

    }

    return $stringy;
  }

  /**
   * Returns a new string with the suffix $substring removed, if present.
   *
   * @param  string $substring The suffix to remove
   *
   * @return Stringy Object having a $str without the suffix $substring
   */
  public function removeRight($substring)

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);

    if ($stringy->endsWith($substring)) {
      $substringLength = UTF8::strlen($substring, $stringy->encoding);

      return $stringy->substr(0, $stringy->length() - $substringLength);
    }

    return $stringy;
  }

  /**
   * Returns a repeated string given a multiplier.
   *
   * @param  int $multiplier The number of times to repeat the string
   *
   * @return Stringy Object with a repeated str
   */
  public function repeat($multiplier)
  {
    $repeated = UTF8::str_repeat($this->str, $multiplier);

    return static::create($repeated, $this->encoding);
  }

  /**
   * Replaces all occurrences of $search in $str by $replacement.
   *
   * @param  string $search      The needle to search for
   * @param  string $replacement The string to replace with
   *
   * @return Stringy Object with the resulting $str after the replacements
   */
  public function replace($search, $replacement)
  {
    return $this->regexReplace(preg_quote($search, '/'), UTF8::str_replace('\\', '\\\\', $replacement));
  }

  /**
   * Replaces all occurrences of $search from the beginning of string with $replacement
   *
   * @param string $search
   * @param string $replacement
   *
   * @return Stringy Object with the resulting $str after the replacements
   */
  public function replaceBeginning($search, $replacement)
  {
    $str = $this->regexReplace('^' . preg_quote($search, '/'), UTF8::str_replace('\\', '\\\\', $replacement));

    return static::create($str, $this->encoding);
  }

  /**
   * Replaces all occurrences of $search from the ending of string with $replacement
   *
   * @param string $search
   * @param string $replacement
   *
   * @return Stringy Object with the resulting $str after the replacements
   */
  public function replaceEnding($search, $replacement)
  {
    $str = $this->regexReplace(preg_quote($search, '/') . '$', UTF8::str_replace('\\', '\\\\', $replacement));

    return static::create($str, $this->encoding);
  }

  /**
   * Returns a reversed string. A multibyte version of strrev().
   *
   * @return Stringy Object with a reversed $str
   */
  public function reverse()
  {
    $reversed = UTF8::strrev($this->str);

    return static::create($reversed, $this->encoding);
  }

  /**
   * Truncates the string to a given length, while ensuring that it does not
   * split words. If $substring is provided, and truncating occurs, the
   * string is further truncated so that the substring may be appended without
   * exceeding the desired length.
   *
   * @param  int    $length    Desired length of the truncated string
   * @param  string $substring The substring to append if it can fit
   *
   * @return Stringy Object with the resulting $str after truncating
   */
  public function safeTruncate($length, $substring = '')
  {
    $stringy = static::create($this->str, $this->encoding);
    if ($length >= $stringy->length()) {
      return $stringy;
    }

    // Need to further trim the string so we can append the substring
    $encoding = $stringy->encoding;
    $substringLength = UTF8::strlen($substring, $encoding);
    $length -= $substringLength;

    $truncated = UTF8::substr($stringy->str, 0, $length, $encoding);

    // If the last word was truncated
    if (UTF8::strpos($stringy->str, ' ', $length - 1, $encoding) != $length) {
      // Find pos of the last occurrence of a space, get up to that
      $lastPos = UTF8::strrpos($truncated, ' ', 0, $encoding);

$encoding is of type string, but the function expects a boolean.

      $truncated = UTF8::substr($truncated, 0, $lastPos, $encoding);

It seems like $lastPos defined by \voku\helper\UTF8::strrpos($truncated, ' ', 0, $encoding) on line 1308 can also be of type boolean or double; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

    }

    $stringy->str = $truncated . $substring;

    return $stringy;
  }

  /**
   * A multibyte string shuffle function. It returns a string with its
   * characters in random order.
   *
   * @return Stringy Object with a shuffled $str
   */
  public function shuffle()
  {
    $shuffledStr = UTF8::str_shuffle($this->str);

    return static::create($shuffledStr, $this->encoding);
  }

  /**
   * Converts the string into an URL slug. This includes replacing non-ASCII
   * characters with their closest ASCII equivalents, removing remaining
   * non-ASCII and non-alphanumeric characters, and replacing whitespace with
   * $replacement. The replacement defaults to a single dash, and the string
   * is also converted to lowercase.
   *
   * @param string $replacement The string used to replace whitespace
   * @param string $language    The language for the url
   * @param bool   $strToLower  string to lower
   *
   * @return Stringy Object whose $str has been converted to an URL slug
   */
  public function slugify($replacement = '-', $language = 'de', $strToLower = true)
  {
    $slug = URLify::slug($this->str, $language, $replacement, $strToLower);

    return static::create($slug, $this->encoding);
  }

  /**
   * escape html
   *
   * @return Stringy
   */
  public function escape()
  {
    $str = UTF8::htmlspecialchars(
        $this->str,
        ENT_QUOTES | ENT_SUBSTITUTE,
        $this->encoding
    );

    return static::create($str, $this->encoding);
  }

  /**
   * remove xss from html
   *
   * @return Stringy
   */
  public function removeXss()
  {
    static $antiXss = null;

    if ($antiXss === null) {
      $antiXss = new AntiXSS();
    }

    $str = $antiXss->xss_clean($this->str);

    return static::create($str, $this->encoding);
  }

  /**
   * remove html
   *
   * @param $allowableTags
   *
   * @return Stringy
   */
  public function removeHtml($allowableTags = null)
  {
    $str = UTF8::strip_tags($this->str, $allowableTags);

    return static::create($str, $this->encoding);
  }

  /**
   * Returns the substring beginning at $start, and up to, but not including
   * the index specified by $end. If $end is omitted, the function extracts
   * the remaining string. If $end is negative, it is computed from the end
   * of the string.
   *
   * @param  int $start Initial index from which to begin extraction
   * @param  int $end   Optional index at which to end extraction
   *
   * @return Stringy Object with its $str being the extracted substring
   */
  public function slice($start, $end = null)
  {
    if ($end === null) {
      $length = $this->length();
    } elseif ($end >= 0 && $end <= $start) {
      return static::create('', $this->encoding);
    } elseif ($end < 0) {
      $length = $this->length() + $end - $start;
    } else {
      $length = $end - $start;
    }

    $str = UTF8::substr($this->str, $start, $length, $this->encoding);

It seems like $length can also be of type boolean or double; however, voku\helper\UTF8::substr() does only seem to accept integer|null, maybe add an additional type check?

    return static::create($str, $this->encoding);
  }

  /**
   * Splits the string with the provided regular expression, returning an
   * array of Stringy objects. An optional integer $limit will truncate the
   * results.
   *
   * @param  string $pattern The regex with which to split the string
   * @param  int    $limit   Optional maximum number of results to return
   *
   * @return Stringy[] An array of Stringy objects
   */
  public function split($pattern, $limit = null)
  {
    if ($limit === 0) {
      return array();
    }

    // UTF8::split errors when supplied an empty pattern in < PHP 5.4.13
    // and current versions of HHVM (3.8 and below)
    if ($pattern === '') {
      return array(static::create($this->str, $this->encoding));
    }

    // UTF8::split returns the remaining unsplit string in the last index when
    // supplying a limit
    if ($limit > 0) {
      $limit += 1;
    } else {
      $limit = -1;
    }

    $array = preg_split('/' . preg_quote($pattern, '/') . '/u', $this->str, $limit);

    if ($limit > 0 && count($array) === $limit) {
      array_pop($array);
    }

    /** @noinspection CallableInLoopTerminationConditionInspection */
    for ($i = 0; $i < count($array); $i++) {

It seems like you are calling the size function count() as part of the test condition. You might want to compute the size beforehand, and not on each iteration.

This code seems to be duplicated across your project.

      $array[$i] = static::create($array[$i], $this->encoding);
    }

    return $array;
  }

  /**
   * Surrounds $str with the given substring.
   *
   * @param  string $substring The substring to add to both sides
   *
   * @return Stringy Object whose $str had the substring both prepended and
   *                 appended
   */
  public function surround($substring)
  {
    $str = implode('', array($substring, $this->str, $substring));

    return static::create($str, $this->encoding);
  }

  /**
   * Returns a case swapped version of the string.
   *
   * @return Stringy Object whose $str has each character's case swapped
   */
  public function swapCase()
  {
    $stringy = static::create($this->str, $this->encoding);
    $encoding = $stringy->encoding;

    $stringy->str = preg_replace_callback(
        '/[\S]/u',
        function($match) use ($encoding) {
          $marchToUpper = UTF8::strtoupper($match[0], $encoding);

          if ($match[0] == $marchToUpper) {
            return UTF8::strtolower($match[0], $encoding);
          } else {
            return $marchToUpper;
          }
        },
        $stringy->str
    );

    return $stringy;
  }

  /**
   * Returns a string with smart quotes, ellipsis characters, and dashes from
   * Windows-1252 (commonly used in Word documents) replaced by their ASCII
   * equivalents.
   *
   * @return Stringy Object whose $str has those characters removed
   */
  public function tidy()
  {
    $str = UTF8::normalize_msword($this->str);

    return static::create($str, $this->encoding);
  }

  /**
   * Returns a trimmed string with the first letter of each word capitalized.
   * Also accepts an array, $ignore, allowing you to list words not to be
   * capitalized.
   *
   * @param  array $ignore An array of words not to capitalize
   *
   * @return Stringy Object with a titleized $str
   */
  public function titleize($ignore = null)
  {
    $stringy = static::create($this->trim(), $this->encoding);
    $encoding = $this->encoding;

    $stringy->str = preg_replace_callback(
        '/([\S]+)/u',
        function($match) use ($encoding, $ignore) {
          if ($ignore && in_array($match[0], $ignore, true)) {
            return $match[0];
          } else {
            $stringy = new Stringy($match[0], $encoding);

            return (string) $stringy->toLowerCase()->upperCaseFirst();
          }
        },
        $stringy->str
    );

    return $stringy;
  }

  /**
   * Converts all characters in the string to lowercase. An alias for PHP's
   * UTF8::strtolower().
   *
   * @return Stringy Object with all characters of $str being lowercase
   */
  public function toLowerCase()
  {
    $str = UTF8::strtolower($this->str, $this->encoding);

    return static::create($str, $this->encoding);
  }

  /**
   * Returns true if the string is base64 encoded, false otherwise.
   *
   * @return bool Whether or not $str is base64 encoded
   */
  public function isBase64()
  {
    if (
        $this->str !== ''
        &&
        base64_encode(base64_decode($this->str, true)) === $this->str
    ) {
      return true;
    } else {
      return false;
    }
  }

  /**
   * Returns an ASCII version of the string. A set of non-ASCII characters are
   * replaced with their closest ASCII counterparts, and the rest are removed
   * unless instructed otherwise.
   *
   * @return Stringy Object whose $str contains only ASCII characters
   */
  public function toAscii()
  {
    $str = UTF8::toAscii($this->str);

    return static::create($str, $this->encoding);
  }

  /**
   * Returns a boolean representation of the given logical string value.
   * For example, 'true', '1', 'on' and 'yes' will return true. 'false', '0',
   * 'off', and 'no' will return false. In all instances, case is ignored.
   * For other numeric strings, their sign will determine the return value.
   * In addition, blank strings consisting of only whitespace will return
   * false. For all other strings, the return value is a result of a
   * boolean cast.
   *
   * @return bool A boolean value for the string
   */
  public function toBoolean()
  {
    $key = $this->toLowerCase()->str;
    $map = array(
        'true'  => true,
        '1'     => true,
        'on'    => true,
        'yes'   => true,
        'false' => false,
        '0'     => false,
        'off'   => false,
        'no'    => false,
    );

    if (array_key_exists($key, $map)) {
      return $map[$key];
    } elseif (is_numeric($this->str)) {
      return ((int) $this->str > 0);
    } else {
      return (bool) $this->regexReplace('[[:space:]]', '')->str;
    }
  }

  /**
   * Converts each tab in the string to some number of spaces, as defined by
   * $tabLength. By default, each tab is converted to 4 consecutive spaces.
   *
   * @param  int $tabLength Number of spaces to replace each tab with
   *
   * @return Stringy Object whose $str has had tabs switched to spaces
   */
  public function toSpaces($tabLength = 4)

This method seems to be duplicated in your project.

  {
    $spaces = UTF8::str_repeat(' ', $tabLength);
    $str = UTF8::str_replace("\t", $spaces, $this->str);

    return static::create($str, $this->encoding);
  }

  /**
   * Converts each occurrence of some consecutive number of spaces, as
   * defined by $tabLength, to a tab. By default, each 4 consecutive spaces
   * are converted to a tab.
   *
   * @param  int $tabLength Number of spaces to replace with a tab
   *
   * @return Stringy Object whose $str has had spaces switched to tabs
   */
  public function toTabs($tabLength = 4)

This method seems to be duplicated in your project.

  {
    $spaces = UTF8::str_repeat(' ', $tabLength);
    $str = UTF8::str_replace($spaces, "\t", $this->str);

    return static::create($str, $this->encoding);
  }

  /**
   * Converts the first character of each word in the string to uppercase.
   *
   * @return Stringy Object with all characters of $str being title-cased
   */
  public function toTitleCase()
  {
    // "mb_convert_case()" used a polyfill from the "UTF8"-Class
    $str = mb_convert_case($this->str, MB_CASE_TITLE, $this->encoding);

    return static::create($str, $this->encoding);
  }

  /**
   * Converts all characters in the string to uppercase. An alias for PHP's
   * UTF8::strtoupper().
   *
   * @return Stringy Object with all characters of $str being uppercase
   */
  public function toUpperCase()
  {
    $str = UTF8::strtoupper($this->str, $this->encoding);

    return static::create($str, $this->encoding);
  }

  /**
   * Returns a string with whitespace removed from the start of the string.
   * Supports the removal of unicode whitespace. Accepts an optional
   * string of characters to strip instead of the defaults.
   *
   * @param  string $chars Optional string of characters to strip
   *
   * @return Stringy Object with a trimmed $str
   */
  public function trimLeft($chars = null)

This method seems to be duplicated in your project.

  {
    if (!$chars) {

The expression $chars of type string|null is loosely compared to false; this is ambiguous if the string can be empty. You might want to explicitly use === null instead.

      $chars = '[:space:]';
    } else {
      $chars = preg_quote($chars, '/');
    }

    return $this->regexReplace("^[$chars]+", '');
  }

  /**
   * Returns a string with whitespace removed from the end of the string.
   * Supports the removal of unicode whitespace. Accepts an optional
   * string of characters to strip instead of the defaults.
   *
   * @param  string $chars Optional string of characters to strip
   *
   * @return Stringy Object with a trimmed $str
   */
  public function trimRight($chars = null)

This method seems to be duplicated in your project.

  {
    if (!$chars) {

The expression $chars of type string|null is loosely compared to false; this is ambiguous if the string can be empty. You might want to explicitly use === null instead.

      $chars = '[:space:]';
    } else {
      $chars = preg_quote($chars, '/');
    }

    return $this->regexReplace("[$chars]+\$", '');
  }

  /**
   * Truncates the string to a given length. If $substring is provided, and
   * truncating occurs, the string is further truncated so that the substring
   * may be appended without exceeding the desired length.
   *
   * @param  int    $length    Desired length of the truncated string
   * @param  string $substring The substring to append if it can fit
   *
   * @return Stringy Object with the resulting $str after truncating
   */
  public function truncate($length, $substring = '')

This method seems to be duplicated in your project.

  {
    $stringy = static::create($this->str, $this->encoding);
    if ($length >= $stringy->length()) {
      return $stringy;
    }

    // Need to further trim the string so we can append the substring
    $substringLength = UTF8::strlen($substring, $stringy->encoding);
    $length -= $substringLength;

    $truncated = UTF8::substr($stringy->str, 0, $length, $stringy->encoding);
    $stringy->str = $truncated . $substring;

    return $stringy;
  }

  /**
   * Returns a lowercase and trimmed string separated by underscores.
   * Underscores are inserted before uppercase characters (with the exception
   * of the first character of the string), and in place of spaces as well as
   * dashes.
   *
   * @return Stringy Object with an underscored $str
   */
  public function underscored()
  {
    return $this->delimit('_');
  }

  /**
   * Returns an UpperCamelCase version of the supplied string. It trims
   * surrounding spaces, capitalizes letters following digits, spaces, dashes
   * and underscores, and removes spaces, dashes, underscores.
   *
   * @return Stringy Object with $str in UpperCamelCase
   */
  public function upperCamelize()
  {
    return $this->camelize()->upperCaseFirst();
  }

  /**
   * Returns a camelCase version of the string. Trims surrounding spaces,
   * capitalizes letters following digits, spaces, dashes and underscores,
   * and removes spaces, dashes, as well as underscores.
   *
   * @return Stringy Object with $str in camelCase
   */
  public function camelize()
  {
    $encoding = $this->encoding;
    $stringy = $this->trim()->lowerCaseFirst();
    $stringy->str = preg_replace('/^[-_]+/', '', $stringy->str);

    $stringy->str = preg_replace_callback(
        '/[-_\s]+(.)?/u',
        function($match) use ($encoding) {
          if (isset($match[1])) {
            return UTF8::strtoupper($match[1], $encoding);
          } else {
            return '';
          }
        },
        $stringy->str
    );

    $stringy->str = preg_replace_callback(
        '/[\d]+(.)?/u',
        function($match) use ($encoding) {
          return UTF8::strtoupper($match[0], $encoding);
        },
        $stringy->str
    );

    return $stringy;
  }

  /**
   * Converts the first character of the string to lower case.
   *
   * @return Stringy Object with the first character of $str being lower case
   */
  public function lowerCaseFirst()

This method seems to be duplicated in your project.

  {
    $first = UTF8::substr($this->str, 0, 1, $this->encoding);
    $rest = UTF8::substr(
        $this->str, 1, $this->length() - 1,
        $this->encoding
    );

    $str = UTF8::strtolower($first, $this->encoding) . $rest;

    return static::create($str, $this->encoding);
  }
}