Adding readString() and readStringUntil() to Stream (Adrian McEwen).

This isn't necessarily a particularly efficient implementation (it
allocates memory one character at a time and so may lead to
fragmentation) but it seems to work.

http://code.google.com/p/arduino/issues/detail?id=454

cores/arduino/Stream.cpp

@@ -244,3 +244,27 @@ size_t Stream::readBytesUntil(char terminator, char *buffer, size_t length)
   return index; // return number of characters, not including null terminator
 }
 
+String Stream::readString()
+{
+  String ret;
+  int c = timedRead();
+  while (c >= 0)
+  {
+    ret += (char)c;
+    c = timedRead();
+  }
+  return ret;
+}
+
+String Stream::readStringUntil(char terminator)
+{
+  String ret;
+  int c = timedRead();
+  while (c >= 0 && c != terminator)
+  {
+    ret += (char)c;
+    c = timedRead();
+  }
+  return ret;
+}
+

cores/arduino/Stream.h

@@ -82,6 +82,8 @@ class Stream : public Print
   // returns the number of characters placed in the buffer (0 means no valid data found)
 
   // Arduino String functions to be added here
+  String readString();
+  String readStringUntil(char terminator);
 
   protected:
   long parseInt(char skipChar); // as above but the given skipChar is ignored