Merge pull request #365 from czaraugust/master

Adding some speed improvments

src/PubSubClient.cpp

@@ -1,4 +1,5 @@
 /*
+
   PubSubClient.cpp - A simple client for MQTT.
   Nick O'Leary
   http://knolleary.net
@@ -269,7 +270,7 @@ uint16_t PubSubClient::readPacket(uint8_t* lengthLength) {
         if(!readByte(&digit)) return 0;
         buffer[len++] = digit;
         length += (digit & 127) * multiplier;
-        multiplier *= 128;
+        multiplier <<=7; //multiplier *= 128
     } while ((digit & 128) != 0);
     *lengthLength = len-1;
 
@@ -432,8 +433,8 @@ boolean PubSubClient::publish_P(const char* topic, const uint8_t* payload, unsig
     buffer[pos++] = header;
     len = plength + 2 + tlen;
     do {
-        digit = len % 128;
-        len = len / 128;
+        digit = len  & 127; //digit = len %128
+        len >>= 7; //len = len / 128
         if (len > 0) {
             digit |= 0x80;
         }
@@ -492,8 +493,9 @@ size_t PubSubClient::buildHeader(uint8_t header, uint8_t* buf, uint16_t length)
     uint8_t pos = 0;
     uint16_t len = length;
     do {
-        digit = len % 128;
-        len = len / 128;
+
+        digit = len  & 127; //digit = len %128
+        len >>= 7; //len = len / 128
         if (len > 0) {
             digit |= 0x80;
         }