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1#! /usr/bin/perl -w
2
3# Script to take the output of nroff -man and remove all the backspacing and
4# the page footers and the screen commands etc so that it is more usefully
5# readable online. In fact, in the latest nroff, intermediate footers don't
6# seem to be generated any more.
7
8$blankcount = 0;
9$lastwascut = 0;
10$firstheader = 1;
11
12# Input on STDIN; output to STDOUT.
13
14while (<STDIN>)
15  {
16  s/\x1b\[\d+m//g;   # Remove screen controls "ESC [ number m"
17  s/.\x8//g;         # Remove "char, backspace"
18
19  # Handle header lines. Retain only the first one we encounter, but remove
20  # the blank line that follows. Any others (e.g. at end of document) and the
21  # following blank line are dropped.
22
23  if (/^PCRE(\w*)\(([13])\)\s+PCRE\1\(\2\)$/)
24    {
25    if ($firstheader)
26      {
27      $firstheader = 0;
28      print;
29      $lastprinted = $_;
30      $lastwascut = 0;
31      }
32    $_=<STDIN>;       # Remove a blank that follows
33    next;
34    }
35
36  # Count runs of empty lines
37
38  if (/^\s*$/)
39    {
40    $blankcount++;
41    $lastwascut = 0;
42    next;
43    }
44
45  # If a chunk of lines has been cut out (page footer) and the next line
46  # has a different indentation, put back one blank line.
47
48  if ($lastwascut && $blankcount < 1 && defined($lastprinted))
49    {
50    ($a) = $lastprinted =~ /^(\s*)/;
51    ($b) = $_ =~ /^(\s*)/;
52    $blankcount++ if ($a ne $b);
53    }
54
55  # We get here only when we have a non-blank line in hand. If it was preceded
56  # by 3 or more blank lines, read the next 3 lines and see if they are blank.
57  # If so, remove all 7 lines, and remember that we have just done a cut.
58
59  if ($blankcount >= 3)
60    {
61    for ($i = 0; $i < 3; $i++)
62      {
63      $next[$i] = <STDIN>;
64      $next[$i] = "" if !defined $next[$i];
65      $next[$i] =~ s/\x1b\[\d+m//g;   # Remove screen controls "ESC [ number m"
66      $next[$i] =~ s/.\x8//g;         # Remove "char, backspace"
67      }
68
69    # Cut out chunks of the form <3 blanks><non-blank><3 blanks>
70
71    if ($next[0] =~ /^\s*$/ &&
72        $next[1] =~ /^\s*$/ &&
73        $next[2] =~ /^\s*$/)
74      {
75      $blankcount -= 3;
76      $lastwascut = 1;
77      }
78
79    # Otherwise output the saved blanks, the current, and the next three
80    # lines. Remember the last printed line.
81
82    else
83      {
84      for ($i = 0; $i < $blankcount; $i++) { print "\n"; }
85      print;
86      for ($i = 0; $i < 3; $i++)
87        {
88        $next[$i] =~ s/.\x8//g;
89        print $next[$i];
90        $lastprinted = $_;
91        }
92      $lastwascut = 0;
93      $blankcount = 0;
94      }
95    }
96
97  # This non-blank line is not preceded by 3 or more blank lines. Output
98  # any blanks there are, and the line. Remember it. Force two blank lines
99  # before headings.
100
101  else
102    {
103    $blankcount = 2 if /^\S/ && !/^Last updated/ && !/^Copyright/ &&
104      defined($lastprinted);
105    for ($i = 0; $i < $blankcount; $i++) { print "\n"; }
106    print;
107    $lastprinted = $_;
108    $lastwascut = 0;
109    $blankcount = 0;
110    }
111  }
112
113# End
114