pcre2/CleanTxt

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2014-09-23 13:35:51 +02:00
#! /usr/bin/perl -w
# Script to take the output of nroff -man and remove all the backspacing and
# the page footers and the screen commands etc so that it is more usefully
# readable online. In fact, in the latest nroff, intermediate footers don't
# seem to be generated any more.
$blankcount = 0;
$lastwascut = 0;
$firstheader = 1;
# Input on STDIN; output to STDOUT.
while (<STDIN>)
{
s/\x1b\[\d+m//g; # Remove screen controls "ESC [ number m"
s/.\x8//g; # Remove "char, backspace"
# Handle header lines. Retain only the first one we encounter, but remove
# the blank line that follows. Any others (e.g. at end of document) and the
# following blank line are dropped.
if (/^PCRE(\w*)\(([13])\)\s+PCRE\1\(\2\)$/)
{
if ($firstheader)
{
$firstheader = 0;
print;
$lastprinted = $_;
$lastwascut = 0;
}
$_=<STDIN>; # Remove a blank that follows
next;
}
# Count runs of empty lines
if (/^\s*$/)
{
$blankcount++;
$lastwascut = 0;
next;
}
# If a chunk of lines has been cut out (page footer) and the next line
# has a different indentation, put back one blank line.
if ($lastwascut && $blankcount < 1 && defined($lastprinted))
{
($a) = $lastprinted =~ /^(\s*)/;
($b) = $_ =~ /^(\s*)/;
$blankcount++ if ($a ne $b);
}
# We get here only when we have a non-blank line in hand. If it was preceded
# by 3 or more blank lines, read the next 3 lines and see if they are blank.
# If so, remove all 7 lines, and remember that we have just done a cut.
if ($blankcount >= 3)
{
for ($i = 0; $i < 3; $i++)
{
$next[$i] = <STDIN>;
$next[$i] = "" if !defined $next[$i];
$next[$i] =~ s/\x1b\[\d+m//g; # Remove screen controls "ESC [ number m"
$next[$i] =~ s/.\x8//g; # Remove "char, backspace"
}
# Cut out chunks of the form <3 blanks><non-blank><3 blanks>
if ($next[0] =~ /^\s*$/ &&
$next[1] =~ /^\s*$/ &&
$next[2] =~ /^\s*$/)
{
$blankcount -= 3;
$lastwascut = 1;
}
# Otherwise output the saved blanks, the current, and the next three
# lines. Remember the last printed line.
else
{
for ($i = 0; $i < $blankcount; $i++) { print "\n"; }
print;
for ($i = 0; $i < 3; $i++)
{
$next[$i] =~ s/.\x8//g;
print $next[$i];
$lastprinted = $_;
}
$lastwascut = 0;
$blankcount = 0;
}
}
# This non-blank line is not preceded by 3 or more blank lines. Output
# any blanks there are, and the line. Remember it. Force two blank lines
# before headings.
else
{
$blankcount = 2 if /^\S/ && !/^Last updated/ && !/^Copyright/ &&
defined($lastprinted);
for ($i = 0; $i < $blankcount; $i++) { print "\n"; }
print;
$lastprinted = $_;
$lastwascut = 0;
$blankcount = 0;
}
}
# End