From 00776994e1869c1482b5cbe186cd0454f88da714 Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bcmi-labs.cc>
Date: Wed, 23 Aug 2017 16:59:04 +0200
Subject: [PATCH 1/2] Some updates on Stream and Print class.

---
 cores/arduino/Print.cpp | 4 ++--
 cores/arduino/Print.h   | 9 +++++++++
 cores/arduino/Stream.h  | 1 -
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/cores/arduino/Print.cpp b/cores/arduino/Print.cpp
index 33ee7210f..136329cca 100644
--- a/cores/arduino/Print.cpp
+++ b/cores/arduino/Print.cpp
@@ -238,14 +238,14 @@ size_t Print::printFloat(double number, uint8_t digits)
 
   // Print the decimal point, but only if there are digits beyond
   if (digits > 0) {
-    n += print(".");
+    n += print('.');
   }
 
   // Extract digits from the remainder one at a time
   while (digits-- > 0)
   {
     remainder *= 10.0;
-    unsigned int toPrint = (unsigned int)remainder;
+    unsigned int toPrint = (unsigned int)(remainder);
     n += print(toPrint);
     remainder -= toPrint;
   }
diff --git a/cores/arduino/Print.h b/cores/arduino/Print.h
index 9fc267424..dfb645cbb 100644
--- a/cores/arduino/Print.h
+++ b/cores/arduino/Print.h
@@ -28,6 +28,9 @@
 #define DEC 10
 #define HEX 16
 #define OCT 8
+#ifdef BIN // Prevent warnings if BIN is previously defined in "iotnx4.h" or similar
+#undef BIN
+#endif
 #define BIN 2
 
 class Print
@@ -54,6 +57,10 @@ class Print
       return write((const uint8_t *)buffer, size);
     }
 
+    // default to zero, meaning "a single write may block"
+    // should be overriden by subclasses with buffering
+    virtual int availableForWrite() { return 0; }
+
     size_t print(const __FlashStringHelper *);
     size_t print(const String &);
     size_t print(const char[]);
@@ -78,6 +85,8 @@ class Print
     size_t println(double, int = 2);
     size_t println(const Printable&);
     size_t println(void);
+
+    virtual void flush() { /* Empty implementation for backward compatibility */ }
 };
 
 #endif
diff --git a/cores/arduino/Stream.h b/cores/arduino/Stream.h
index 5c9701f59..c3311c3cd 100644
--- a/cores/arduino/Stream.h
+++ b/cores/arduino/Stream.h
@@ -59,7 +59,6 @@ class Stream : public Print
     virtual int available() = 0;
     virtual int read() = 0;
     virtual int peek() = 0;
-    virtual void flush() = 0;
 
     Stream() {_timeout=1000;}
 

From 402a335d933744478b9164e52ebfba81cd7b27a4 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@bcmi-labs.cc>
Date: Wed, 23 Aug 2017 12:51:23 -0400
Subject: [PATCH 2/2] Change return value of I2S:: availableForWrite to match
 new Print API

---
 libraries/I2S/src/I2S.cpp | 2 +-
 libraries/I2S/src/I2S.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libraries/I2S/src/I2S.cpp b/libraries/I2S/src/I2S.cpp
index cf8e8683f..97690e0f3 100644
--- a/libraries/I2S/src/I2S.cpp
+++ b/libraries/I2S/src/I2S.cpp
@@ -280,7 +280,7 @@ size_t I2SClass::write(const uint8_t *buffer, size_t size)
   return write((const void*)buffer, size);
 }
 
-size_t I2SClass::availableForWrite()
+int I2SClass::availableForWrite()
 {
   if (_state != I2S_STATE_TRANSMITTER) {
     enableTransmitter();
diff --git a/libraries/I2S/src/I2S.h b/libraries/I2S/src/I2S.h
index 12ec0863d..855f26b4c 100644
--- a/libraries/I2S/src/I2S.h
+++ b/libraries/I2S/src/I2S.h
@@ -51,7 +51,7 @@ class I2SClass : public Stream
   virtual size_t write(uint8_t);
   virtual size_t write(const uint8_t *buffer, size_t size);
 
-  virtual size_t availableForWrite();
+  virtual int availableForWrite();
 
   int read(void* buffer, size_t size);