优化url编解码

src/Http/strCoding.cpp

@@ -76,9 +76,9 @@ string strCoding::UrlEncode(const string &str) {
 		if (isalnum((uint8_t)ch)) {
             out.push_back(ch);
 		}else {
-			char tempbuff[4];
-			sprintf(tempbuff, "%%%X%X", (uint8_t)str[i] >> 4,(uint8_t)str[i] % 16);
-            out.append(tempbuff);
+			char buf[4];
+			sprintf(buf, "%%%X%X", (uint8_t)ch >> 4,(uint8_t)ch & 0x0F);
+            out.append(buf);
 		}
 	}
 	return out;