Added printf() and vprintf() to Fl_Text_Buffer

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12483 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Text_Buffer.H

@@ -22,6 +22,7 @@
 #ifndef FL_TEXT_BUFFER_H
 #define FL_TEXT_BUFFER_H
 
+#include <stdarg.h>	/* va_start/end */
 
 #undef ASSERT_UTF8
 
@@ -287,6 +288,9 @@ public:
    */
   void append(const char* t) { insert(length(), t); }
 
+  void vprintf(const char *fmt, va_list ap);
+  void printf(const char* fmt, ...);
+
   /**
    Deletes a range of characters in the buffer.
    \param start byte offset to first character to be removed

src/Fl_Text_Buffer.cxx

@@ -292,6 +292,50 @@ void Fl_Text_Buffer::insert(int pos, const char *text)
 }
 
 
+/**
+ Can be used by subclasses that need their own printf() style functionality.
+ e.g. Fl_Simple_Terminal::printf() would wrap around this method.
+ \note The expanded string is currently limited to 1024 characters. 
+ \param[in] fmt is a printf format string for the message text.
+ \param[in] ap is a va_list created by va_start() and closed with va_end(),
+               which the caller is responsible for handling.
+*/
+void Fl_Text_Buffer::vprintf(const char *fmt, va_list ap) {
+  char buffer[1024];    // XXX: 1024 should be user configurable
+  ::vsnprintf(buffer, 1024, fmt, ap);
+  buffer[1024-1] = 0;	// XXX: MICROSOFT
+  append(buffer);
+}
+
+
+/**
+ Appends printf formatted messages to the end of the buffer.
+ Example:
+ \code
+ #include <FL/Fl_Text_Display.H>
+ int main(..) {
+     :
+     // Create a text display widget and assign it a text buffer
+     Fl_Text_Display *tdsp = new Fl_Text_Display(..);
+     Fl_Text_Buffer *tbuf = new Fl_Text_Buffer();
+     tdsp->buffer(tbuf);
+     :
+     // Append three lines of formatted text to the buffer
+     tbuf->printf("The current date is: %s.\nThe time is: %s\n", date_str, time_str);
+     tbuf->printf("The current PID is %ld.\n", (long)getpid());
+     :
+ \endcode
+ \note The expanded string is currently limited to 1024 characters. 
+ \param[in] fmt is a printf format string for the message text.
+*/
+void Fl_Text_Buffer::printf(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  Fl_Text_Buffer::vprintf(fmt,ap);
+  va_end(ap);
+}
+
+
 /*
  Replace a range of text with new text.
  Start and end must be at a character boundary.