CMS 2.0

2026-01-06 10:02:25 +01:00
parent f685c2490a
commit b52d3a11be
111 changed files with 12830 additions and 76 deletions
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpMqtt\Client\Concerns;
+
+/**
+ * Provides common methods to encode data before sending it to a broker
+ * and to decode data received from a broker.
+ *
+ * @package PhpMqtt\Client\Concerns
+ */
+trait TranscodesData
+{
+    /**
+     * Creates a string which is prefixed with its own length as bytes.
+     * This means a string like 'hello world' will become
+     *
+     *   \x00\x0bhello world
+     *
+     * where \x00\0x0b is the hex representation of 00000000 00001011 = 11
+     */
+    protected function buildLengthPrefixedString(string $data): string
+    {
+        $length = strlen($data);
+        $msb    = $length >> 8;
+        $lsb    = $length % 256;
+
+        return chr($msb) . chr($lsb) . $data;
+    }
+
+    /**
+     * Converts the given string to a number, assuming it is an MSB encoded message id.
+     * MSB means preceding characters have higher value.
+     */
+    protected function decodeMessageId(string $encodedMessageId): int
+    {
+        $length = strlen($encodedMessageId);
+        $result = 0;
+
+        foreach (str_split($encodedMessageId) as $index => $char) {
+            $result += ord($char) << (($length - 1) * 8 - ($index * 8));
+        }
+
+        return $result;
+    }
+
+    /**
+     * Encodes the given message identifier as string.
+     */
+    protected function encodeMessageId(int $messageId): string
+    {
+        return chr($messageId >> 8) . chr($messageId % 256);
+    }
+
+    /**
+     * Encodes the length of a message as string, so it can be transmitted
+     * over the wire.
+     */
+    protected function encodeMessageLength(int $length): string
+    {
+        $result = '';
+
+        do {
+            $digit  = $length % 128;
+            $length = $length >> 7;
+
+            // if there are more digits to encode, set the top bit of this digit
+            if ($length > 0) {
+                $digit = ($digit | 0x80);
+            }
+
+            $result .= chr($digit);
+        } while ($length > 0);
+
+        return $result;
+    }
+}