From fcc4188b15d53446612ef70c4e6a3d1b6287638a Mon Sep 17 00:00:00 2001
From: "David A. Mellis" <d.mellis@arduino.cc>
Date: Sat, 20 Nov 2010 11:45:05 -0500
Subject: [PATCH] SD File object implements Stream.

Added peak() and available() using a single byte buffer.
Added flush().
---
 hardware/arduino/cores/arduino/Stream.h |  1 +
 libraries/SD/File.cpp                   | 21 +++++++++++++++++++
 libraries/SD/SD.cpp                     |  1 +
 libraries/SD/SD.h                       | 28 ++++++++++++++-----------
 4 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/hardware/arduino/cores/arduino/Stream.h b/hardware/arduino/cores/arduino/Stream.h
index c98759b31..93d8275dc 100644
--- a/hardware/arduino/cores/arduino/Stream.h
+++ b/hardware/arduino/cores/arduino/Stream.h
@@ -28,6 +28,7 @@ class Stream : public Print
   public:
     virtual int available() = 0;
     virtual int read() = 0;
+    virtual int peek() = 0;
     virtual void flush() = 0;
 };
 
diff --git a/libraries/SD/File.cpp b/libraries/SD/File.cpp
index 91aaa557b..d09bd8f85 100644
--- a/libraries/SD/File.cpp
+++ b/libraries/SD/File.cpp
@@ -26,10 +26,31 @@ void File::write(const uint8_t *buf, size_t size) {
   SD.file.write(buf, size);
 }
 
+int File::peek() {
+  if (SD.c != -1) return SD.c;
+  SD.c = SD.file.read();
+  return SD.c;
+}
+
 int File::read() {
+  if (SD.c != -1) {
+    int tmp = SD.c;
+    SD.c = -1;
+    return tmp;
+  }
   return SD.file.read();
 }
 
+int File::available() {
+  if (SD.c != -1) return 1;
+  SD.c = SD.file.read();
+  return SD.c != -1;
+}
+
+void File::flush() {
+  SD.file.sync();
+}
+
 void File::close() {
   SD.file.close();
 }
diff --git a/libraries/SD/SD.cpp b/libraries/SD/SD.cpp
index 8c9e63dd4..ec6c7fc7b 100644
--- a/libraries/SD/SD.cpp
+++ b/libraries/SD/SD.cpp
@@ -297,6 +297,7 @@ boolean callback_openPath(SdFile& parentDir, char *filePathComponent,
     SDClass *p_MemoryCard = static_cast<SDClass*>(object);
     p_MemoryCard->file.open(parentDir, filePathComponent,
 			    p_MemoryCard->fileOpenMode);
+    p_MemoryCard->c = -1;
     // TODO: Return file open result?
     return false;
   }
diff --git a/libraries/SD/SD.h b/libraries/SD/SD.h
index 704d0655d..f7c9fe4f6 100644
--- a/libraries/SD/SD.h
+++ b/libraries/SD/SD.h
@@ -23,26 +23,28 @@
 // Use this to configure the chip select pin of the SD card.
 #define SD_CARD_CHIP_SELECT_PIN 4 // For use with Arduino Ethernet Shield
 
-class File : public Print {
-  public:
-    virtual void write(uint8_t);
-    virtual void write(const char *str);
-    virtual void write(const uint8_t *buf, size_t size);
-    int read();
-    void close();
-    operator bool();
+class File : public Stream {
+public:
+  virtual void write(uint8_t);
+  virtual void write(const char *str);
+  virtual void write(const uint8_t *buf, size_t size);
+  virtual int read();
+  virtual int peek();
+  virtual int available();
+  virtual void flush();
+  void close();
+  operator bool();
 };
 
 class SDClass {
 
- private:
+private:
   // These are required for initialisation and use of sdfatlib
   Sd2Card card;
   SdVolume volume;
   SdFile root;
   
-  
- public:
+public:
   // This needs to be called to set up the connection to the SD card
   // before other methods are used.
   void begin(uint8_t csPin = SD_CARD_CHIP_SELECT_PIN);
@@ -59,7 +61,7 @@ class SDClass {
   // do not exist they will be created.
   boolean makeDir(char *filepath);
 
- private:
+private:
   SdFile file;
 
   // This is used to determine the mode used to open a file
@@ -69,6 +71,8 @@ class SDClass {
   // It shouldn't be set directly--it is set via the parameters to `open`.
   int fileOpenMode;
   
+  int c;
+  
   friend class File;
   friend boolean callback_openPath(SdFile&, char *, boolean, void *); 
 };