refactor and fix methods in StringObject classes

CHANGELOG.md

@@ -3,12 +3,15 @@
 Fixed:
 
 * Fix accessing undefined properties in method \Swoole\NameResolver::checkResponse(). ([commit](https://github.com/swoole/library/commit/7a6396e45f4d4517a049584a746285d6501cf71d))
+* Fix the implementation of method `\Swoole\MultibyteStringObject::chunk()`.
 
 Changed:
 
 * Refactor: Rename parameter in method `\Swoole\Database\PDOStatementProxy::setFetchMode()` for consistency.
 * Refactor: Rename parameter in method `\Swoole\MultibyteStringObject::substr()` for consistency.
 * Refactor: Enhance method `\Swoole\FastCGI\Message::withBody()` with explicit parameter type.
+* Refactor: Rename parameter and default value of method `\Swoole\StringObject::chunkSplit()` for consistency.
+* Refactor: Rename parameter in method `\Swoole\StringObject::chunk()` for consistency.
 * FastCGI: Make constructor argument required for records. ([commit](https://github.com/swoole/library/commit/497bb74eaad51f661c91bc936f976b8660ce716c))
 
 ## 5.1.2 (2024-01-24)

src/core/MultibyteStringObject.php

@@ -52,10 +52,11 @@ public function substr(int $start, ?int $length = null, ?string $encoding = null
     }
 
     /**
-     * @todo This method is not implemented correctly.
+     * {@inheritDoc}
+     * @see https://www.php.net/mb_str_split
      */
-    public function chunk(int $splitLength = 1, ?int $limit = null): ArrayObject
+    public function chunk(int $length = 1): ArrayObject
     {
-        return static::detectArrayType(mb_split($this->string, ...func_get_args()));
+        return static::detectArrayType(mb_str_split($this->string, $length));
     }
 }

src/core/StringObject.php

@@ -167,14 +167,27 @@ public function char(int $index): string
         return $this->string[$index];
     }
 
-    public function chunkSplit(int $chunkLength = 76, string $chunkEnd = ''): static
+    /**
+     * Get a new string object by splitting the string of current object into smaller chunks.
+     *
+     * @param int $length The chunk length.
+     * @param string $separator The line ending sequence.
+     * @see https://www.php.net/chunk_split
+     */
+    public function chunkSplit(int $length = 76, string $separator = "\r\n"): static
     {
-        return new static(chunk_split($this->string, ...func_get_args())); // @phpstan-ignore new.static
+        return new static(chunk_split($this->string, $length, $separator)); // @phpstan-ignore new.static
     }
 
-    public function chunk(int $splitLength = 1): ArrayObject
+    /**
+     * Convert a string to an array object of class \Swoole\ArrayObject.
+     *
+     * @param int $length Maximum length of the chunk.
+     * @see https://www.php.net/str_split
+     */
+    public function chunk(int $length = 1): ArrayObject
     {
-        return static::detectArrayType(str_split($this->string, ...func_get_args()));
+        return static::detectArrayType(str_split($this->string, $length));
     }
 
     public function toString(): string