binary db (8x smaller)

habr_twister.php

@@ -16,8 +16,8 @@ $twister = new TwisterPost('habr_ru'); // set user name
 $twister->twisterPath = '.' . DIRECTORY_SEPARATOR . 'twister-win32-bundle' . DIRECTORY_SEPARATOR;
 
 // Initialise RSS database
-require_once 'habrrssdb.php';
-$db = new HabrRSSDb('habr_db.dat');
+require_once 'rssdb.php';
+$db = new RSSDb('habr_ru.dat');
 
 foreach ($rss->channel->item as $item) {
     $link  = (string)$item->link;

habrrssdb.php

@@ -1,30 +0,0 @@
-<?php
-
-class HabrRSSDb
-{
-    protected $hDatabase = null;
-
-    public function __construct($dbFile)
-    {
-        fclose(fopen($dbFile, 'a')); // create file if not exists
-        $this->hDatabase = fopen($dbFile, 'r+');
-    }
-
-    public function __destruct()
-    {
-        fclose($this->hDatabase);
-    }
-
-    public function isPublished($id)
-    {
-        fseek($this->hDatabase, $id);
-        $status = fgetc($this->hDatabase);
-        return $status === '1';
-    }
-
-    public function setPublished($id)
-    {
-        fseek($this->hDatabase, $id);
-        fwrite($this->hDatabase, '1');
-    }
-}

rssdb.php

@@ -0,0 +1,41 @@
+<?php
+
+class RSSDb
+{
+    protected $hDatabase = null;
+    protected $minId = 0;
+    protected $bits = array(0=>1, 2, 4, 8, 16, 32, 64, 128);
+
+    public function __construct($dbFile, $minId = 0)
+    {
+        fclose(fopen($dbFile, 'a')); // create file if not exists
+        $this->hDatabase = fopen($dbFile, 'r+');
+        $this->minId = $minId;
+    }
+
+    public function __destruct()
+    {
+        fclose($this->hDatabase);
+    }
+
+    public function isPublished($id)
+    {
+        $id -= $this->minId;
+        if ($id < 0) return true;
+        $pos = intval($id/8);
+        fseek($this->hDatabase, $pos);
+        $status = ord(fgetc($this->hDatabase));
+        return (bool)($status & $this->bits[$id % 8]);
+    }
+
+    public function setPublished($id)
+    {
+        $id -= $this->minId;
+        if ($id < 0) return;
+        $pos = intval($id/8);
+        fseek($this->hDatabase, $pos);
+        $status = ord(fgetc($this->hDatabase));
+        fseek($this->hDatabase, $pos);
+        fwrite($this->hDatabase, chr($status | $this->bits[$id % 8]));
+    }
+}