FormattedStream.h   [plain text]

//===-- llvm/Support/FormattedStream.h - Formatted streams ------*- C++ -*-===//
//                     The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This file contains raw_ostream implementations for streams to do
// things like pretty-print comments.


#include "llvm/Support/raw_ostream.h"
#include <utility>

namespace llvm {

/// formatted_raw_ostream - A raw_ostream that wraps another one and keeps track
/// of line and column position, allowing padding out to specific column
/// boundaries and querying the number of lines written to the stream.
class formatted_raw_ostream : public raw_ostream {
  /// DELETE_STREAM - Tell the destructor to delete the held stream.
  static const bool DELETE_STREAM = true;

  /// PRESERVE_STREAM - Tell the destructor to not delete the held
  /// stream.
  static const bool PRESERVE_STREAM = false;

  /// TheStream - The real stream we output to. We set it to be
  /// unbuffered, since we're already doing our own buffering.
  raw_ostream *TheStream;

  /// DeleteStream - Do we need to delete TheStream in the
  /// destructor?
  bool DeleteStream;

  /// Position - The current output column and line of the data that's
  /// been flushed and the portion of the buffer that's been
  /// scanned.  The line and column scheme is zero-based.
  std::pair<unsigned, unsigned> Position;

  /// Scanned - This points to one past the last character in the
  /// buffer we've scanned.
  const char *Scanned;

  virtual void write_impl(const char *Ptr, size_t Size) LLVM_OVERRIDE;

  /// current_pos - Return the current position within the stream,
  /// not counting the bytes currently in the buffer.
  virtual uint64_t current_pos() const LLVM_OVERRIDE {
    // Our current position in the stream is all the contents which have been
    // written to the underlying stream (*not* the current position of the
    // underlying stream).
    return TheStream->tell();

  /// ComputePosition - Examine the given output buffer and figure out the new
  /// position after output.
  void ComputePosition(const char *Ptr, size_t size);

  /// formatted_raw_ostream - Open the specified file for
  /// writing. If an error occurs, information about the error is
  /// put into ErrorInfo, and the stream should be immediately
  /// destroyed; the string will be empty if no error occurred.
  /// As a side effect, the given Stream is set to be Unbuffered.
  /// This is because formatted_raw_ostream does its own buffering,
  /// so it doesn't want another layer of buffering to be happening
  /// underneath it.
  formatted_raw_ostream(raw_ostream &Stream, bool Delete = false) 
    : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) {
    setStream(Stream, Delete);
  explicit formatted_raw_ostream()
    : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) {
    Scanned = 0;

  ~formatted_raw_ostream() {

  void setStream(raw_ostream &Stream, bool Delete = false) {

    TheStream = &Stream;
    DeleteStream = Delete;

    // This formatted_raw_ostream inherits from raw_ostream, so it'll do its
    // own buffering, and it doesn't need or want TheStream to do another
    // layer of buffering underneath. Resize the buffer to what TheStream
    // had been using, and tell TheStream not to do its own buffering.
    if (size_t BufferSize = TheStream->GetBufferSize())

    Scanned = 0;

  /// PadToColumn - Align the output to some column number.  If the current
  /// column is already equal to or more than NewCol, PadToColumn inserts one
  /// space.
  /// \param NewCol - The column to move to.
  formatted_raw_ostream &PadToColumn(unsigned NewCol);

  /// getColumn - Return the column number
  unsigned getColumn() { return Position.first; }

  /// getLine - Return the line number
  unsigned getLine() { return Position.second; }
  raw_ostream &resetColor() {
    return *this;
  raw_ostream &reverseColor() {
    return *this;
  raw_ostream &changeColor(enum Colors Color,
                           bool Bold,
                           bool BG) {
    TheStream->changeColor(Color, Bold, BG);
    return *this;
  bool is_displayed() const {
    return TheStream->is_displayed();

  void releaseStream() {
    // Delete the stream if needed. Otherwise, transfer the buffer
    // settings from this raw_ostream back to the underlying stream.
    if (!TheStream)
    if (DeleteStream)
      delete TheStream;
    else if (size_t BufferSize = GetBufferSize())

/// fouts() - This returns a reference to a formatted_raw_ostream for
/// standard output.  Use it like: fouts() << "foo" << "bar";
formatted_raw_ostream &fouts();

/// ferrs() - This returns a reference to a formatted_raw_ostream for
/// standard error.  Use it like: ferrs() << "foo" << "bar";
formatted_raw_ostream &ferrs();

/// fdbgs() - This returns a reference to a formatted_raw_ostream for
/// debug output.  Use it like: fdbgs() << "foo" << "bar";
formatted_raw_ostream &fdbgs();

} // end llvm namespace