add clear

officialaccount/dcaler/PKCS7Encoder.php

@@ -0,0 +1,46 @@
+<?php
+
+
+namespace officialaccount\dcaler;
+
+
+class PKCS7Encoder
+{
+	public static $block_size = 32;
+
+	/**
+	 * @param $text
+	 * @return string
+	 */
+	function encode($text)
+	{
+		$block_size = PKCS7Encoder::$block_size;
+		$text_length = strlen($text);
+		//计算需要填充的位数
+		$amount_to_pad = PKCS7Encoder::$block_size - ($text_length % PKCS7Encoder::$block_size);
+		if ($amount_to_pad == 0) {
+			$amount_to_pad = PKCS7Encoder::$block_size;
+		}
+		//获得补位所用的字符
+		$pad_chr = chr($amount_to_pad);
+		$tmp = "";
+		for ($index = 0; $index < $amount_to_pad; $index++) {
+			$tmp .= $pad_chr;
+		}
+		return $text . $tmp;
+	}
+
+	/**
+	 * @param $text
+	 * @return false|string
+	 */
+	function decode($text)
+	{
+
+		$pad = ord(substr($text, -1));
+		if ($pad < 1 || $pad > 32) {
+			$pad = 0;
+		}
+		return substr($text, 0, (strlen($text) - $pad));
+	}
+}