1//===-- llvm/Support/FormattedStream.cpp - Formatted streams ----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains the implementation of formatted_raw_ostream.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Support/Debug.h"
15#include "llvm/Support/FormattedStream.h"
16#include <algorithm>
17
18using namespace llvm;
19
20/// CountColumns - Examine the given char sequence and figure out which
21/// column we end up in after output.
22///
23static unsigned CountColumns(unsigned Column, const char *Ptr, size_t Size) {
24  // Keep track of the current column by scanning the string for
25  // special characters
26
27  for (const char *End = Ptr + Size; Ptr != End; ++Ptr) {
28    ++Column;
29    if (*Ptr == '\n' || *Ptr == '\r')
30      Column = 0;
31    else if (*Ptr == '\t')
32      // Assumes tab stop = 8 characters.
33      Column += (8 - (Column & 0x7)) & 0x7;
34  }
35
36  return Column;
37}
38
39/// ComputeColumn - Examine the current output and figure out which
40/// column we end up in after output.
41void formatted_raw_ostream::ComputeColumn(const char *Ptr, size_t Size) {
42  // If our previous scan pointer is inside the buffer, assume we already
43  // scanned those bytes. This depends on raw_ostream to not change our buffer
44  // in unexpected ways.
45  if (Ptr <= Scanned && Scanned <= Ptr + Size) {
46    // Scan all characters added since our last scan to determine the new
47    // column.
48    ColumnScanned = CountColumns(ColumnScanned, Scanned,
49                                 Size - (Scanned - Ptr));
50  } else
51    ColumnScanned = CountColumns(ColumnScanned, Ptr, Size);
52
53  // Update the scanning pointer.
54  Scanned = Ptr + Size;
55}
56
57/// PadToColumn - Align the output to some column number.
58///
59/// \param NewCol - The column to move to.
60///
61formatted_raw_ostream &formatted_raw_ostream::PadToColumn(unsigned NewCol) {
62  // Figure out what's in the buffer and add it to the column count.
63  ComputeColumn(getBufferStart(), GetNumBytesInBuffer());
64
65  // Output spaces until we reach the desired column.
66  indent(std::max(int(NewCol - ColumnScanned), 1));
67  return *this;
68}
69
70void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) {
71  // Figure out what's in the buffer and add it to the column count.
72  ComputeColumn(Ptr, Size);
73
74  // Write the data to the underlying stream (which is unbuffered, so
75  // the data will be immediately written out).
76  TheStream->write(Ptr, Size);
77
78  // Reset the scanning pointer.
79  Scanned = 0;
80}
81
82/// fouts() - This returns a reference to a formatted_raw_ostream for
83/// standard output.  Use it like: fouts() << "foo" << "bar";
84formatted_raw_ostream &llvm::fouts() {
85  static formatted_raw_ostream S(outs());
86  return S;
87}
88
89/// ferrs() - This returns a reference to a formatted_raw_ostream for
90/// standard error.  Use it like: ferrs() << "foo" << "bar";
91formatted_raw_ostream &llvm::ferrs() {
92  static formatted_raw_ostream S(errs());
93  return S;
94}
95
96/// fdbgs() - This returns a reference to a formatted_raw_ostream for
97/// the debug stream.  Use it like: fdbgs() << "foo" << "bar";
98formatted_raw_ostream &llvm::fdbgs() {
99  static formatted_raw_ostream S(dbgs());
100  return S;
101}
102