Infinite bitmask implementation sources.

src/InfiniteBitmask.php

@@ -0,0 +1,111 @@
+<?php
+namespace Aliance\InfiniteBitmask;
+
+use Aliance\Bitmask\Bitmask;
+
+/**
+ * Infinite bitmask implementation.
+ */
+class InfiniteBitmask
+{
+    /**
+     * Mask slices list.
+     * @var int[]
+     */
+    private $maskSlices = [];
+
+    /**
+     * @param int[] $maskSlices
+     * @throws \InvalidArgumentException
+     */
+    public function __construct(array $maskSlices = [])
+    {
+        if (!is_array($maskSlices)) {
+            throw new \InvalidArgumentException('Passed invalid argument: ' . gettype($maskSlices));
+        }
+
+        $this->maskSlices = $maskSlices;
+    }
+
+    /**
+     * @param int $bit
+     * @return $this
+     */
+    public function setBit($bit)
+    {
+        $indexKey = $this->getBitIndex($bit);
+
+        if (!isset($this->maskSlices[$indexKey])) {
+            $this->maskSlices[$indexKey] = 0;
+        }
+
+        $Bitmask = Bitmask::create($this->maskSlices[$indexKey]);
+        $Bitmask->setBit($this->getBitInSlice($bit));
+        $this->maskSlices[$indexKey] = $Bitmask->getMask();
+
+        return $this;
+    }
+
+    /**
+     * Returns bit index at bitmask slice.
+     * For example, if we store [0;62] bits:
+     * - bits [  0; 62] will be at index 0;
+     * - bits [ 63;125] will be at index 1;
+     * - bits [126;188] will be at index 2;
+     * @param int $bit
+     * @return int
+     */
+    protected function getBitIndex($bit)
+    {
+        return (int)($bit / Bitmask::MAX_BIT + 1);
+    }
+
+    /**
+     * Return bit representation in current bitmask slice.
+     * For example:
+     * - bit   0 will be  0 bit at slice #0;
+     * - bit   5 will be  5 bit at slice #0;
+     * - bit  62 will be 62 bit at slice #0;
+     * - bit  63 will be  0 bit at slice #1;
+     * - bit  68 will be  5 bit at slice #1;
+     * - bit 126 will be  0 bit at slice #2;
+     * @param int $bit
+     * @return int
+     */
+    protected function getBitInSlice($bit)
+    {
+        return $bit % Bitmask::MAX_BIT + 1;
+    }
+
+    /**
+     * @param int $bit
+     * @return bool
+     */
+    public function issetBit($bit)
+    {
+        $indexKey = $this->getBitIndex($bit);
+
+        if (!isset($this->maskSlices[$indexKey])) {
+            return false;
+        }
+
+        return Bitmask::create($this->maskSlices[$indexKey])->issetBit($this->getBitInSlice($bit));
+    }
+
+    /**
+     * @param int $bit
+     * @return $this
+     */
+    public function unsetBit($bit)
+    {
+        $indexKey = $this->getBitIndex($bit);
+
+        if (isset($this->maskSlices[$indexKey])) {
+            $Bitmask = Bitmask::create($this->maskSlices[$indexKey]);
+            $Bitmask->unsetBit($this->getBitInSlice($bit));
+            $this->maskSlices[$indexKey] = $Bitmask->getMask();
+        }
+
+        return $this;
+    }
+}