LS String PHP lib added

To compress and decompress strings with LZ compression

LZCompressor/LZContext.php

@@ -0,0 +1,91 @@
+<?php
+namespace LZCompressor;
+
+class LZContext
+{
+    /**
+     * @var array
+     */
+    public $dictionary = [];
+
+    /**
+     * @var array
+     */
+    public $dictionaryToCreate = [];
+
+    /**
+     * @var string
+     */
+    public $c = '';
+
+    /**
+     * @var string
+     */
+    public $wc = '';
+
+    /**
+     * @var string
+     */
+    public $w = '';
+
+    /**
+     * @var int
+     */
+    public $enlargeIn = 2;
+
+    /**
+     * @var int
+     */
+    public $dictSize = 3;
+
+    /**
+     * @var int
+     */
+    public $numBits = 2;
+
+    /**
+     * @var LZData
+     */
+    public $data;
+
+    function __construct()
+    {
+        $this->data = new LZData;
+    }
+
+    // Helper
+
+    /**
+     * @param string $val
+     * @return bool
+     */
+    public function dictionaryContains($val) {
+        return array_key_exists($val, $this->dictionary);
+    }
+
+    /**
+     * @param $val
+     */
+    public function addToDictionary($val) {
+        $this->dictionary[$val] = $this->dictSize++;
+    }
+
+    /**
+     * @param string $val
+     * @return bool
+     */
+    public function dictionaryToCreateContains($val) {
+        return array_key_exists($val, $this->dictionaryToCreate);
+    }
+
+    /**
+     * decrements enlargeIn and extends numbits in case enlargeIn drops to 0
+     */
+    public function enlargeIn() {
+        $this->enlargeIn--;
+        if($this->enlargeIn==0) {
+            $this->enlargeIn = pow(2, $this->numBits);
+            $this->numBits++;
+        }
+    }
+}