Add Excerpt class

src/Parsing/Excerpt.php

@@ -0,0 +1,80 @@
+<?php
+
+namespace Erusev\Parsedown\Parsing;
+
+final class Excerpt
+{
+    /** @var string */
+    private $context;
+
+    /** @var int */
+    private $offset;
+
+    /** @var string */
+    private $text;
+
+    /**
+     * @param string $context
+     * @param int $offset
+     */
+    public function __construct($context, $offset)
+    {
+        $this->context = $context;
+        $this->offset = $offset;
+        $this->text = \substr($context, $offset);
+    }
+
+    /**
+     * @param string $mask
+     * @return self
+     */
+    public function pushingOffsetTo($mask)
+    {
+        return $this->addingToOffset(\strcspn($this->text, $mask));
+    }
+
+    /**
+     * @param int $offset
+     * @return self
+     */
+    public function choppingFromOffset($offset)
+    {
+        return new self(\substr($this->context, $offset), 0);
+    }
+
+    /**
+     * @param int $offset
+     * @return self
+     */
+    public function choppingUpToOffset($offset)
+    {
+        return new self(\substr($this->context, 0, $offset), 0);
+    }
+
+    /**
+     * @param int $offsetIncrement
+     * @return self
+     */
+    public function addingToOffset($offsetIncrement)
+    {
+        return new self($this->context, $this->offset + $offsetIncrement);
+    }
+
+    /** @return string */
+    public function context()
+    {
+        return $this->context;
+    }
+
+    /** @return int */
+    public function offset()
+    {
+        return $this->offset;
+    }
+
+    /** @return string */
+    public function text()
+    {
+        return $this->text;
+    }
+}