From ce128543b779eba0cdf59583404b42ce7e3eaa3b Mon Sep 17 00:00:00 2001
From: Avamander <Avamander@users.noreply.github.com>
Date: Fri, 9 Feb 2018 17:46:12 +0200
Subject: [PATCH] Added packet peek functionality (#106)

---
 RF24Network.cpp | 34 +++++++++++++++++++++++++++-------
 RF24Network.h   | 13 +++++++++++++
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/RF24Network.cpp b/RF24Network.cpp
index a8dd94bd..a01ada7b 100644
--- a/RF24Network.cpp
+++ b/RF24Network.cpp
@@ -604,14 +604,10 @@ uint16_t RF24Network::parent() const
 }
 
 /******************************************************************/
-/*uint8_t RF24Network::peekData(){
-		
-		return frame_queue[0];
-}*/
 
 uint16_t RF24Network::peek(RF24NetworkHeader& header)
 {
-  if ( available() )
+  if (available())
   {
   #if defined (RF24_LINUX)
     RF24NetworkFrame frame = frame_queue.front();
@@ -630,12 +626,36 @@ uint16_t RF24Network::peek(RF24NetworkHeader& header)
 
 /******************************************************************/
 
+void RF24Network::peek(RF24NetworkHeader& header, void* message, uint16_t maxlen)
+{
+#if defined (RF24_LINUX)
+  if (available()) 
+  { // TODO: Untested
+    RF24NetworkFrame frame = frame_queue.front();
+    memcpy(&header, &(frame.header), sizeof(RF24NetworkHeader));
+    memcpy(message, frame.message_buffer, maxlen);
+  }
+#else
+  if(available()) 
+  {
+    memcpy(&header, frame_queue, 8); //Copy the header
+    if(maxlen > 0) 
+    {
+      memcpy(message, frame_queue + 10, maxlen); //Copy the message
+    }
+  }
+#endif
+}
+
+/******************************************************************/
+
 uint16_t RF24Network::read(RF24NetworkHeader& header,void* message, uint16_t maxlen)
 {
   uint16_t bufsize = 0;
 
  #if defined (RF24_LINUX)
-   if ( available() ) {
+   if (available())
+   {
     RF24NetworkFrame frame = frame_queue.front();
 
     // How much buffer size should we actually copy?
@@ -651,7 +671,7 @@ uint16_t RF24Network::read(RF24NetworkHeader& header,void* message, uint16_t max
     frame_queue.pop();
   }
 #else  
-  if ( available() )
+  if (available())
   {
     
 	memcpy(&header,frame_queue,8);
diff --git a/RF24Network.h b/RF24Network.h
index af0cbe93..6a9d6259 100644
--- a/RF24Network.h
+++ b/RF24Network.h
@@ -431,6 +431,19 @@ class RF24Network
    */
   uint16_t peek(RF24NetworkHeader& header);
 
+  /**
+   * Read the next available payload
+   *
+   * Reads the next available payload without advancing to the next
+   * incoming message.  Useful for doing a transparent packet 
+   * manipulation layer on top of RF24Network.
+   *
+   * @param[out] header The header (envelope) of this message
+   * @param[out] message Pointer to memory where the message should be placed
+   * @param maxlen Amount of bytes to copy to message.
+   */
+  void peek(RF24NetworkHeader& header, void* message, uint16_t maxlen);
+
   /**
    * Read a message
    *