max receivable MQTT packet is 16 bits (tested with 300 byte packet receive)

also fixd buffer printer to have 16 bit length

Adafruit_MQTT.cpp

@@ -30,8 +30,8 @@ static char *dtostrf (double val, signed char width, unsigned char prec, char *s
 }
 #endif
 
-void printBuffer(uint8_t *buffer, uint8_t len) {
-  for (uint8_t i=0; i<len; i++) {
+void printBuffer(uint8_t *buffer, uint16_t len) {
+  for (uint16_t i=0; i<len; i++) {
     if (isprint(buffer[i]))
       DEBUG_PRINTER.write(buffer[i]);
     else
@@ -189,7 +189,7 @@ int8_t Adafruit_MQTT::connect() {
     return -1;
 
   // Read connect response packet and verify it
-  len = readFullPacket(buffer, CONNECT_TIMEOUT_MS);
+  len = readFullPacket(buffer, MAXBUFFERSIZE, CONNECT_TIMEOUT_MS);
   if (len != 4)
     return -1;
   if ((buffer[0] != (MQTT_CTRL_CONNECTACK << 4)) || (buffer[1] != 2))
@@ -230,7 +230,7 @@ int8_t Adafruit_MQTT::connect() {
 
 uint16_t Adafruit_MQTT::processPacketsUntil(uint8_t *buffer, uint8_t waitforpackettype, uint16_t timeout) {
   uint16_t len;
-  while (len = readFullPacket(buffer, timeout)) {
+  while (len = readFullPacket(buffer, MAXBUFFERSIZE, timeout)) {
 
     //DEBUG_PRINT("Packet read size: "); DEBUG_PRINTLN(len);
     // TODO: add subscription reading & call back processing here
@@ -243,7 +243,7 @@ uint16_t Adafruit_MQTT::processPacketsUntil(uint8_t *buffer, uint8_t waitforpack
   return 0;
 }
 
-uint16_t Adafruit_MQTT::readFullPacket(uint8_t *buffer, uint16_t timeout) {
+uint16_t Adafruit_MQTT::readFullPacket(uint8_t *buffer, uint16_t maxsize, uint16_t timeout) {
   // will read a packet and Do The Right Thing with length
   uint8_t *pbuff = buffer;
 
@@ -277,7 +277,12 @@ uint16_t Adafruit_MQTT::readFullPacket(uint8_t *buffer, uint16_t timeout) {
 
   DEBUG_PRINT(F("Packet Length:\t")); DEBUG_PRINTLN(value);
   
-  rlen = readPacket(pbuff, value, timeout);
+  if (value > (maxsize - (pbuff-buffer) - 1)) {
+      DEBUG_PRINTLN(F("Packet too big for buffer"));
+      rlen = readPacket(pbuff, (maxsize - (pbuff-buffer) - 1), timeout);
+  } else {
+    rlen = readPacket(pbuff, value, timeout);
+  }
   //DEBUG_PRINT(F("Remaining packet:\t")); DEBUG_PRINTBUFFER(pbuff, rlen);
 
   return ((pbuff - buffer)+rlen);
@@ -322,7 +327,7 @@ bool Adafruit_MQTT::publish(const char *topic, uint8_t *data, uint8_t bLen, uint
 
   // If QOS level is high enough verify the response packet.
   if (qos > 0) {
-    len = readFullPacket(buffer, PUBLISH_TIMEOUT_MS);
+    len = readFullPacket(buffer, MAXBUFFERSIZE, PUBLISH_TIMEOUT_MS);
     DEBUG_PRINT(F("Publish QOS1+ reply:\t"));
     DEBUG_PRINTBUFFER(buffer, len);
     if (len != 4)
@@ -403,7 +408,7 @@ bool Adafruit_MQTT::unsubscribe(Adafruit_MQTT_Subscribe *sub) {
       if(subscriptions[i]->qos > 0 && MQTT_PROTOCOL_LEVEL > 3) {
 
         // wait for UNSUBACK
-        len = readFullPacket(buffer, CONNECT_TIMEOUT_MS);
+        len = readFullPacket(buffer, MAXBUFFERSIZE, CONNECT_TIMEOUT_MS);
         DEBUG_PRINT(F("UNSUBACK:\t"));
         DEBUG_PRINTBUFFER(buffer, len);
 
@@ -427,7 +432,7 @@ Adafruit_MQTT_Subscribe *Adafruit_MQTT::readSubscription(int16_t timeout) {
   uint8_t i, topiclen, datalen;
 
   // Check if data is available to read.
-  uint16_t len = readFullPacket(buffer, timeout); // return one full packet
+  uint16_t len = readFullPacket(buffer, MAXBUFFERSIZE, timeout); // return one full packet
   if (!len)
     return NULL;  // No data available, just quit.
   DEBUG_PRINT("Packet len: "); DEBUG_PRINTLN(len); 

Adafruit_MQTT.h

@@ -78,7 +78,7 @@
 // Largest full packet we're able to send.
 // Need to be able to store at least ~90 chars for a connect packet with full
 // 23 char client ID.
-#define MAXBUFFERSIZE (125)
+#define MAXBUFFERSIZE (150)
 
 #define MQTT_CONN_USERNAMEFLAG    0x80
 #define MQTT_CONN_PASSWORDFLAG    0x40
@@ -99,7 +99,7 @@
 //and returns an int
 typedef void (*SubscribeCallbackType)(char *);  
 
-extern void printBuffer(uint8_t *buffer, uint8_t len);
+extern void printBuffer(uint8_t *buffer, uint16_t len);
 
 class Adafruit_MQTT_Subscribe;  // forward decl
 
@@ -201,10 +201,10 @@ class Adafruit_MQTT {
   // Read MQTT packet from the server.  Will read up to maxlen bytes and store
   // the data in the provided buffer.  Waits up to the specified timeout (in
   // milliseconds) for data to be available. 
-  virtual uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout) = 0;
+  virtual uint16_t readPacket(uint8_t *buffer, uint16_t maxlen, int16_t timeout) = 0;
 
   // Read a full packet, keeping note of the correct length
-  uint16_t readFullPacket(uint8_t *buffer, uint16_t timeout);
+  uint16_t readFullPacket(uint8_t *buffer, uint16_t maxsize, uint16_t timeout);
   // Properly process packets until you get to one you want
   uint16_t processPacketsUntil(uint8_t *buffer, uint8_t waitforpackettype, uint16_t timeout);
 

Adafruit_MQTT_CC3000.h

@@ -100,7 +100,7 @@ class Adafruit_MQTT_CC3000 : public Adafruit_MQTT {
     return mqttclient.connected();
   }
 
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout) {
+  uint16_t readPacket(uint8_t *buffer, uint16_t maxlen, int16_t timeout) {
     /* Read data until either the connection is closed, or the idle timeout is reached. */
     uint16_t len = 0;
     int16_t t = timeout;

Adafruit_MQTT_Client.cpp

@@ -47,7 +47,7 @@ bool Adafruit_MQTT_Client::connected() {
   return client->connected();
 }
 
-uint16_t Adafruit_MQTT_Client::readPacket(uint8_t *buffer, uint8_t maxlen,
+uint16_t Adafruit_MQTT_Client::readPacket(uint8_t *buffer, uint16_t maxlen,
                                           int16_t timeout) {
   /* Read data until either the connection is closed, or the idle timeout is reached. */
   uint16_t len = 0;

Adafruit_MQTT_Client.h

@@ -50,7 +50,7 @@ class Adafruit_MQTT_Client : public Adafruit_MQTT {
   bool connectServer();
   bool disconnectServer();
   bool connected();
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout);
+  uint16_t readPacket(uint8_t *buffer, uint16_t maxlen, int16_t timeout);
   bool sendPacket(uint8_t *buffer, uint8_t len);
 
  private:

Adafruit_MQTT_FONA.h

@@ -68,7 +68,7 @@ class Adafruit_MQTT_FONA : public Adafruit_MQTT {
     return fona->TCPconnected();
   }
 
-  uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout) {
+  uint16_t readPacket(uint8_t *buffer, uint16_t maxlen, int16_t timeout) {
     uint8_t *buffp = buffer;
     DEBUG_PRINTLN(F("Reading data.."));