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/FormattedStream.h"
15 
16 using namespace llvm;
17 
18 /// ComputeColumn - Examine the current output and figure out which
19 /// column we end up in after output.
20 ///
21 void formatted_raw_ostream::ComputeColumn() {
22   // Keep track of the current column by scanning the string for
23   // special characters
24 
25   // The buffer may have been allocated underneath us.
26   if (Scanned == 0 && GetNumBytesInBuffer() != 0) {
27     Scanned = begin();
28   }
29 
30   while (Scanned != end()) {
31     ++ColumnScanned;
32     if (*Scanned == '\n' || *Scanned == '\r')
33       ColumnScanned = 0;
34     else if (*Scanned == '\t')
35       // Assumes tab stop = 8 characters.
36       ColumnScanned += (8 - (ColumnScanned & 0x7)) & 0x7;
37     ++Scanned;
38   }
39 }
40 
41 /// PadToColumn - Align the output to some column number.
42 ///
43 /// \param NewCol - The column to move to.
44 /// \param MinPad - The minimum space to give after the most recent
45 /// I/O, even if the current column + minpad > newcol.
46 ///
47 void formatted_raw_ostream::PadToColumn(unsigned NewCol, unsigned MinPad) {
48   // Figure out what's in the buffer and add it to the column count.
49   ComputeColumn();
50 
51   // Output spaces until we reach the desired column.
52   unsigned num = NewCol - ColumnScanned;
53   if (NewCol < ColumnScanned || num < MinPad)
54     num = MinPad;
55 
56   // Keep a buffer of spaces handy to speed up processing.
57   const char *Spaces = "                                                      "
58     "                                                                         ";
59 
60   assert(num < MAX_COLUMN_PAD && "Unexpectedly large column padding");
61 
62   write(Spaces, num);
63 }
64 
65 /// fouts() - This returns a reference to a formatted_raw_ostream for
66 /// standard output.  Use it like: fouts() << "foo" << "bar";
67 formatted_raw_ostream &llvm::fouts() {
68   static formatted_raw_ostream S(outs());
69   return S;
70 }
71 
72 /// ferrs() - This returns a reference to a formatted_raw_ostream for
73 /// standard error.  Use it like: ferrs() << "foo" << "bar";
74 formatted_raw_ostream &llvm::ferrs() {
75   static formatted_raw_ostream S(errs());
76   return S;
77 }
78