1 files changed, 66 insertions, 5 deletions

diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h
index 34e40da517..58d5be2741 100644
--- a/include/llvm/Support/raw_ostream.h
+++ b/include/llvm/Support/raw_ostream.h
@@ -21,7 +21,8 @@
 #include <iosfwd>
 
 namespace llvm {
-
+  class format_object_base;
+  
 /// raw_ostream - This class implements an extremely fast bulk output stream
 /// that can *only* output to a stream.  It does not support seeking, reopening,
 /// rewinding, line buffered disciplines etc. It is a simple buffer that outputs
@@ -92,11 +93,8 @@ public:
   }
   
   raw_ostream &operator<<(unsigned long N);
-  
   raw_ostream &operator<<(long N);
-  
   raw_ostream &operator<<(unsigned long long N);
-  
   raw_ostream &operator<<(long long N);
   
   raw_ostream &operator<<(unsigned int N) {
@@ -111,9 +109,11 @@ public:
     return this->operator<<(ftostr(N));
   }
   
-  
   raw_ostream &write(const char *Ptr, unsigned Size);
   
+  // Formatted output, see the format() function below.
+  raw_ostream &operator<<(const format_object_base &Fmt);
+  
   //===--------------------------------------------------------------------===//
   // Subclass Interface
   //===--------------------------------------------------------------------===//
@@ -137,6 +137,63 @@ private:
   virtual void handle();
 };
   
+//===----------------------------------------------------------------------===//
+// Formatted Output
+//===----------------------------------------------------------------------===//
+
+/// format_object_base - This is a helper class used for handling formatted
+/// output.  It is the abstract base class of a templated derived class.
+class format_object_base {
+protected:
+  const char *Fmt;
+  virtual void home(); // Out of line virtual method.
+public:
+  format_object_base(const char *fmt) : Fmt(fmt) {}
+  virtual ~format_object_base() {}
+  
+  /// print - Format the object into the specified buffer.  On success, this
+  /// returns the length of the formatted string.  If the buffer is too small,
+  /// this returns a length to retry with, which will be larger than BufferSize.
+  virtual unsigned print(char *Buffer, unsigned BufferSize) const = 0;
+};
+  
+/// format_object - This is a templated helper class used by the format function
+/// that captures the object to be formated and the format string.  When
+/// actually printed, this synthesizes the string into a temporary buffer
+/// provided and returns whether or not it is big enough.
+template <typename T>
+  class format_object : public format_object_base {
+  T Val;
+public:
+  format_object(const char *fmt, const T &val)
+    : format_object_base(fmt), Val(val) {
+  }
+  
+  /// print - Format the object into the specified buffer.  On success, this
+  /// returns the length of the formatted string.  If the buffer is too small,
+  /// this returns a length to retry with, which will be larger than BufferSize.
+  virtual unsigned print(char *Buffer, unsigned BufferSize) const {
+    int N = snprintf(Buffer, BufferSize-1, Fmt, Val);
+    if (N < 0)             // VC++ and old GlibC return negative on overflow.
+      return BufferSize*2;
+    if (unsigned(N) >= BufferSize-1)// Other impls yield number of bytes needed.
+      return N+1;
+    // If N is positive and <= BufferSize-1, then the string fit, yay.
+    return N;
+  }
+};
+
+/// format - This is a helper function that is used to produce formatted output.
+/// This is typically used like:  OS << format("%0.4f", myfloat) << '\n';
+template <typename T>
+inline format_object<T> format(const char *Fmt, const T &Val) {
+  return format_object<T>(Fmt, Val);
+}
+  
+//===----------------------------------------------------------------------===//
+// File Output Streams
+//===----------------------------------------------------------------------===//
+  
 /// raw_fd_ostream - A raw_ostream that writes to a file descriptor.
 ///
 class raw_fd_ostream : public raw_ostream {
@@ -187,6 +244,10 @@ raw_ostream &outs();
 raw_ostream &errs();
   
   
+//===----------------------------------------------------------------------===//
+// Bridge Output Streams
+//===----------------------------------------------------------------------===//
+  
 /// raw_os_ostream - A raw_ostream that writes to an std::ostream.  This is a
 /// simple adaptor class.
 class raw_os_ostream : public raw_ostream {