linux/scripts/cleanfile
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   1#!/usr/bin/env perl
   2# SPDX-License-Identifier: GPL-2.0
   3#
   4# Clean a text file -- or directory of text files -- of stealth whitespace.
   5# WARNING: this can be a highly destructive operation.  Use with caution.
   6#
   7
   8use warnings;
   9use bytes;
  10use File::Basename;
  11
  12# Default options
  13$max_width = 79;
  14
  15# Clean up space-tab sequences, either by removing spaces or
  16# replacing them with tabs.
  17sub clean_space_tabs($)
  18{
  19    no bytes;                   # Tab alignment depends on characters
  20
  21    my($li) = @_;
  22    my($lo) = '';
  23    my $pos = 0;
  24    my $nsp = 0;
  25    my($i, $c);
  26
  27    for ($i = 0; $i < length($li); $i++) {
  28        $c = substr($li, $i, 1);
  29        if ($c eq "\t") {
  30            my $npos = ($pos+$nsp+8) & ~7;
  31            my $ntab = ($npos >> 3) - ($pos >> 3);
  32            $lo .= "\t" x $ntab;
  33            $pos = $npos;
  34            $nsp = 0;
  35        } elsif ($c eq "\n" || $c eq "\r") {
  36            $lo .= " " x $nsp;
  37            $pos += $nsp;
  38            $nsp = 0;
  39            $lo .= $c;
  40            $pos = 0;
  41        } elsif ($c eq " ") {
  42            $nsp++;
  43        } else {
  44            $lo .= " " x $nsp;
  45            $pos += $nsp;
  46            $nsp = 0;
  47            $lo .= $c;
  48            $pos++;
  49        }
  50    }
  51    $lo .= " " x $nsp;
  52    return $lo;
  53}
  54
  55# Compute the visual width of a string
  56sub strwidth($) {
  57    no bytes;                   # Tab alignment depends on characters
  58
  59    my($li) = @_;
  60    my($c, $i);
  61    my $pos = 0;
  62    my $mlen = 0;
  63
  64    for ($i = 0; $i < length($li); $i++) {
  65        $c = substr($li,$i,1);
  66        if ($c eq "\t") {
  67            $pos = ($pos+8) & ~7;
  68        } elsif ($c eq "\n") {
  69            $mlen = $pos if ($pos > $mlen);
  70            $pos = 0;
  71        } else {
  72            $pos++;
  73        }
  74    }
  75
  76    $mlen = $pos if ($pos > $mlen);
  77    return $mlen;
  78}
  79
  80$name = basename($0);
  81
  82@files = ();
  83
  84while (defined($a = shift(@ARGV))) {
  85    if ($a =~ /^-/) {
  86        if ($a eq '-width' || $a eq '-w') {
  87            $max_width = shift(@ARGV)+0;
  88        } else {
  89            print STDERR "Usage: $name [-width #] files...\n";
  90            exit 1;
  91        }
  92    } else {
  93        push(@files, $a);
  94    }
  95}
  96
  97foreach $f ( @files ) {
  98    print STDERR "$name: $f\n";
  99
 100    if (! -f $f) {
 101        print STDERR "$f: not a file\n";
 102        next;
 103    }
 104
 105    if (!open(FILE, '+<', $f)) {
 106        print STDERR "$name: Cannot open file: $f: $!\n";
 107        next;
 108    }
 109
 110    binmode FILE;
 111
 112    # First, verify that it is not a binary file; consider any file
 113    # with a zero byte to be a binary file.  Is there any better, or
 114    # additional, heuristic that should be applied?
 115    $is_binary = 0;
 116
 117    while (read(FILE, $data, 65536) > 0) {
 118        if ($data =~ /\0/) {
 119            $is_binary = 1;
 120            last;
 121        }
 122    }
 123
 124    if ($is_binary) {
 125        print STDERR "$name: $f: binary file\n";
 126        next;
 127    }
 128
 129    seek(FILE, 0, 0);
 130
 131    $in_bytes = 0;
 132    $out_bytes = 0;
 133    $blank_bytes = 0;
 134
 135    @blanks = ();
 136    @lines  = ();
 137    $lineno = 0;
 138
 139    while ( defined($line = <FILE>) ) {
 140        $lineno++;
 141        $in_bytes += length($line);
 142        $line =~ s/[ \t\r]*$//;         # Remove trailing spaces
 143        $line = clean_space_tabs($line);
 144
 145        if ( $line eq "\n" ) {
 146            push(@blanks, $line);
 147            $blank_bytes += length($line);
 148        } else {
 149            push(@lines, @blanks);
 150            $out_bytes += $blank_bytes;
 151            push(@lines, $line);
 152            $out_bytes += length($line);
 153            @blanks = ();
 154            $blank_bytes = 0;
 155        }
 156
 157        $l_width = strwidth($line);
 158        if ($max_width && $l_width > $max_width) {
 159            print STDERR
 160                "$f:$lineno: line exceeds $max_width characters ($l_width)\n";
 161        }
 162    }
 163
 164    # Any blanks at the end of the file are discarded
 165
 166    if ($in_bytes != $out_bytes) {
 167        # Only write to the file if changed
 168        seek(FILE, 0, 0);
 169        print FILE @lines;
 170
 171        if ( !defined($where = tell(FILE)) ||
 172             !truncate(FILE, $where) ) {
 173            die "$name: Failed to truncate modified file: $f: $!\n";
 174        }
 175    }
 176
 177    close(FILE);
 178}
 179