1//===-- llvm/Support/FormattedStream.cpp - Formatted streams ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains the implementation of formatted_raw_ostream.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Support/FormattedStream.h"
14#include "llvm/Support/Debug.h"
15#include "llvm/Support/raw_ostream.h"
16#include <algorithm>
17
18using namespace llvm;
19
20/// UpdatePosition - Examine the given char sequence and figure out which
21/// column we end up in after output, and how many line breaks are contained.
22///
23static void UpdatePosition(std::pair<unsigned, unsigned> &Position, const char *Ptr, size_t Size) {
24  unsigned &Column = Position.first;
25  unsigned &Line = Position.second;
26
27  // Keep track of the current column and line by scanning the string for
28  // special characters
29  for (const char *End = Ptr + Size; Ptr != End; ++Ptr) {
30    ++Column;
31    switch (*Ptr) {
32    case '\n':
33      Line += 1;
34      LLVM_FALLTHROUGH;
35    case '\r':
36      Column = 0;
37      break;
38    case '\t':
39      // Assumes tab stop = 8 characters.
40      Column += (8 - (Column & 0x7)) & 0x7;
41      break;
42    }
43  }
44}
45
46/// ComputePosition - Examine the current output and update line and column
47/// counts.
48void formatted_raw_ostream::ComputePosition(const char *Ptr, size_t Size) {
49  // If our previous scan pointer is inside the buffer, assume we already
50  // scanned those bytes. This depends on raw_ostream to not change our buffer
51  // in unexpected ways.
52  if (Ptr <= Scanned && Scanned <= Ptr + Size)
53    // Scan all characters added since our last scan to determine the new
54    // column.
55    UpdatePosition(Position, Scanned, Size - (Scanned - Ptr));
56  else
57    UpdatePosition(Position, Ptr, Size);
58
59  // Update the scanning pointer.
60  Scanned = Ptr + Size;
61}
62
63/// PadToColumn - Align the output to some column number.
64///
65/// \param NewCol - The column to move to.
66///
67formatted_raw_ostream &formatted_raw_ostream::PadToColumn(unsigned NewCol) {
68  // Figure out what's in the buffer and add it to the column count.
69  ComputePosition(getBufferStart(), GetNumBytesInBuffer());
70
71  // Output spaces until we reach the desired column.
72  indent(std::max(int(NewCol - getColumn()), 1));
73  return *this;
74}
75
76void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) {
77  // Figure out what's in the buffer and add it to the column count.
78  ComputePosition(Ptr, Size);
79
80  // Write the data to the underlying stream (which is unbuffered, so
81  // the data will be immediately written out).
82  TheStream->write(Ptr, Size);
83
84  // Reset the scanning pointer.
85  Scanned = nullptr;
86}
87
88/// fouts() - This returns a reference to a formatted_raw_ostream for
89/// standard output.  Use it like: fouts() << "foo" << "bar";
90formatted_raw_ostream &llvm::fouts() {
91  static formatted_raw_ostream S(outs());
92  return S;
93}
94
95/// ferrs() - This returns a reference to a formatted_raw_ostream for
96/// standard error.  Use it like: ferrs() << "foo" << "bar";
97formatted_raw_ostream &llvm::ferrs() {
98  static formatted_raw_ostream S(errs());
99  return S;
100}
101
102/// fdbgs() - This returns a reference to a formatted_raw_ostream for
103/// the debug stream.  Use it like: fdbgs() << "foo" << "bar";
104formatted_raw_ostream &llvm::fdbgs() {
105  static formatted_raw_ostream S(dbgs());
106  return S;
107}
108