An improved patch for the Client part of issue 416 (adding a multi-byte read). This one moves all of the checking into recv, so that single-byte reads also benefit. It also returns -1 if there's no data available unless we've reached EOF, in which case it returns 0.

libraries/Ethernet/Client.cpp

@@ -77,14 +77,25 @@ int Client::available() {
 
 int Client::read() {
   uint8_t b;
-  if (!available())
+  if ( recv(_sock, &b, 1) )
+  {
+    // recv worked
+    return b;
+  }
+  else
+  {
+    // No data available
     return -1;
-  recv(_sock, &b, 1);
-  return b;
+  }
+}
+
+int Client::read(uint8_t *buf, size_t size) {
+  return recv(_sock, buf, size);
 }
 
 int Client::peek() {
   uint8_t b;
+  // Unlike recv, peek doesn't check to see if there's any data available, so we must
   if (!available())
     return -1;
   ::peek(_sock, &b);

libraries/Ethernet/Client.h

@@ -17,6 +17,7 @@ public:
   virtual void write(const uint8_t *buf, size_t size);
   virtual int available();
   virtual int read();
+  virtual int read(uint8_t *buf, size_t size);
   virtual int peek();
   virtual void flush();
   void stop();

libraries/Ethernet/utility/socket.cpp

@@ -146,14 +146,18 @@ uint16_t send(SOCKET s, const uint8_t * buf, uint16_t len)
  */
 uint16_t recv(SOCKET s, uint8_t *buf, uint16_t len)
 {
-  uint16_t ret=0;
-
-  if ( len > 0 )
+  // Check how much data is available
+  uint16_t ret = W5100.getRXReceivedSize(s);
+  if (ret > len)
   {
-    W5100.recv_data_processing(s, buf, len);
-    W5100.execCmdSn(s, Sock_RECV);
     ret = len;
   }
+
+  if ( ret > 0 )
+  {
+    W5100.recv_data_processing(s, buf, ret);
+    W5100.execCmdSn(s, Sock_RECV);
+  }
   return ret;
 }