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 #include <algorithm>
16 
17 using namespace llvm;
18 
19 /// ComputeColumn - Examine the current output and figure out which
20 /// column we end up in after output.
21 ///
22 void formatted_raw_ostream::ComputeColumn() {
23   // Keep track of the current column by scanning the string for
24   // special characters
25 
26   // The buffer may have been allocated underneath us.
27   if (Scanned == 0 && GetNumBytesInBuffer() != 0) {
28     Scanned = begin();
29   }
30 
31   while (Scanned != end()) {
32     ++ColumnScanned;
33     if (*Scanned == '\n' || *Scanned == '\r')
34       ColumnScanned = 0;
35     else if (*Scanned == '\t')
36       // Assumes tab stop = 8 characters.
37       ColumnScanned += (8 - (ColumnScanned & 0x7)) & 0x7;
38     ++Scanned;
39   }
40 }
41 
42 /// PadToColumn - Align the output to some column number.
43 ///
44 /// \param NewCol - The column to move to.
45 /// \param MinPad - The minimum space to give after the most recent
46 /// I/O, even if the current column + minpad > newcol.
47 ///
48 void formatted_raw_ostream::PadToColumn(unsigned NewCol, unsigned MinPad) {
49   // Figure out what's in the buffer and add it to the column count.
50   ComputeColumn();
51 
52   // Output spaces until we reach the desired column.
53   unsigned num = NewCol - ColumnScanned;
54   if (NewCol < ColumnScanned || num < MinPad)
55     num = MinPad;
56 
57   // Keep a buffer of spaces handy to speed up processing.
58   const char *Spaces = "                                                      "
59     "                                                                         ";
60 
61   assert(num < MAX_COLUMN_PAD && "Unexpectedly large column padding");
62 
63   write(Spaces, num);
64 }
65 
66 /// fouts() - This returns a reference to a formatted_raw_ostream for
67 /// standard output.  Use it like: fouts() << "foo" << "bar";
68 formatted_raw_ostream &llvm::fouts() {
69   static formatted_raw_ostream S(outs());
70   return S;
71 }
72 
73 /// ferrs() - This returns a reference to a formatted_raw_ostream for
74 /// standard error.  Use it like: ferrs() << "foo" << "bar";
75 formatted_raw_ostream &llvm::ferrs() {
76   static formatted_raw_ostream S(errs());
77   return S;
78 }
79