checkpatch.pl

#!/usr/bin/perl -w
# (c) 2001, Dave Jones. (the file handling bit)
# (c) 2005, Joel Schopp <jschopp@austin.ibm.com> (the ugly bit)
# (c) 2007,2008, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite)
# (c) 2008-2010 Andy Whitcroft <apw@canonical.com>
# Licensed under the terms of the GNU GPL License version 2

use strict;
use POSIX;

my $P = $0;
$P =~ s@.*/@@g;

my $V = '0.32';

use Getopt::Long qw(:config no_auto_abbrev);

my $quiet = 0;
my $tree = 1;
my $chk_signoff = 1;
my $chk_patch = 1;
my $tst_only;
my $emacs = 0;
my $terse = 0;
my $file = 0;
my $check = 0;
my $summary = 1;
my $mailback = 0;
my $summary_file = 0;
my $show_types = 0;
my $fix = 0;
my $root;
my %debug;
my %camelcase = ();
my %use_type = ();
my @use = ();
my %ignore_type = ();
my @ignore = ();
my $help = 0;
my $configuration_file = ".checkpatch.conf";
my $max_line_length = 80;
my $ignore_perl_version = 0;
my $minimum_perl_version = 5.10.0;

sub help {
	my ($exitcode) = @_;

	print << "EOM";
Usage: $P [OPTION]... [FILE]...
Version: $V

Options:
  -q, --quiet                quiet
  --no-tree                  run without a kernel tree
  --no-signoff               do not check for 'Signed-off-by' line
  --patch                    treat FILE as patchfile (default)
  --emacs                    emacs compile window format
  --terse                    one line per report
  -f, --file                 treat FILE as regular source file
  --subjective, --strict     enable more subjective tests
  --types TYPE(,TYPE2...)    show only these comma separated message types
  --ignore TYPE(,TYPE2...)   ignore various comma separated message types
  --max-line-length=n        set the maximum line length, if exceeded, warn
  --show-types               show the message "types" in the output
  --root=PATH                PATH to the kernel tree root
  --no-summary               suppress the per-file summary
  --mailback                 only produce a report in case of warnings/errors
  --summary-file             include the filename in summary
  --debug KEY=[0|1]          turn on/off debugging of KEY, where KEY is one of
                             'values', 'possible', 'type', and 'attr' (default
                             is all off)
  --test-only=WORD           report only warnings/errors containing WORD
                             literally
  --fix                      EXPERIMENTAL - may create horrible results
                             If correctable single-line errors exist, create
                             "<inputfile>.EXPERIMENTAL-checkpatch-fixes"
                             with potential errors corrected to the preferred
                             checkpatch style
  --ignore-perl-version      override checking of perl version.  expect
                             runtime errors.
  -h, --help, --version      display this help and exit

When FILE is - read standard input.
EOM

	exit($exitcode);
}

my $conf = which_conf($configuration_file);
if (-f $conf) {
	my @conf_args;
	open(my $conffile, '<', "$conf")
	    or warn "$P: Can't find a readable $configuration_file file $!\n";

	while (<$conffile>) {
		my $line = $_;

		$line =~ s/\s*\n?$//g;
		$line =~ s/^\s*//g;
		$line =~ s/\s+/ /g;

		next if ($line =~ m/^\s*#/);
		next if ($line =~ m/^\s*$/);

		my @words = split(" ", $line);
		foreach my $word (@words) {
			last if ($word =~ m/^#/);
			push (@conf_args, $word);
		}
	}
	close($conffile);
	unshift(@ARGV, @conf_args) if @conf_args;
}

GetOptions(
	'q|quiet+'	=> \$quiet,
	'tree!'		=> \$tree,
	'signoff!'	=> \$chk_signoff,
	'patch!'	=> \$chk_patch,
	'emacs!'	=> \$emacs,
	'terse!'	=> \$terse,
	'f|file!'	=> \$file,
	'subjective!'	=> \$check,
	'strict!'	=> \$check,
	'ignore=s'	=> \@ignore,
	'types=s'	=> \@use,
	'show-types!'	=> \$show_types,
	'max-line-length=i' => \$max_line_length,
	'root=s'	=> \$root,
	'summary!'	=> \$summary,
	'mailback!'	=> \$mailback,
	'summary-file!'	=> \$summary_file,
	'fix!'		=> \$fix,
	'ignore-perl-version!' => \$ignore_perl_version,
	'debug=s'	=> \%debug,
	'test-only=s'	=> \$tst_only,
	'h|help'	=> \$help,
	'version'	=> \$help
) or help(1);

help(0) if ($help);

my $exit = 0;

if ($^V && $^V lt $minimum_perl_version) {
	printf "$P: requires at least perl version %vd\n", $minimum_perl_version;
	if (!$ignore_perl_version) {
		exit(1);
	}
}

if ($#ARGV < 0) {
	print "$P: no input files\n";
	exit(1);
}

sub hash_save_array_words {
	my ($hashRef, $arrayRef) = @_;

	my @array = split(/,/, join(',', @$arrayRef));
	foreach my $word (@array) {
		$word =~ s/\s*\n?$//g;
		$word =~ s/^\s*//g;
		$word =~ s/\s+/ /g;
		$word =~ tr/[a-z]/[A-Z]/;

		next if ($word =~ m/^\s*#/);
		next if ($word =~ m/^\s*$/);

		$hashRef->{$word}++;
	}
}

sub hash_show_words {
	my ($hashRef, $prefix) = @_;

	if ($quiet == 0 && keys %$hashRef) {
		print "NOTE: $prefix message types:";
		foreach my $word (sort keys %$hashRef) {
			print " $word";
		}
		print "\n\n";
	}
}

hash_save_array_words(\%ignore_type, \@ignore);
hash_save_array_words(\%use_type, \@use);

my $dbg_values = 0;
my $dbg_possible = 0;
my $dbg_type = 0;
my $dbg_attr = 0;
for my $key (keys %debug) {
	## no critic
	eval "\${dbg_$key} = '$debug{$key}';";
	die "$@" if ($@);
}

my $rpt_cleaners = 0;

if ($terse) {
	$emacs = 1;
	$quiet++;
}

if ($tree) {
	if (defined $root) {
		if (!top_of_kernel_tree($root)) {
			die "$P: $root: --root does not point at a valid tree\n";
		}
	} else {
		if (top_of_kernel_tree('.')) {
			$root = '.';
		} elsif ($0 =~ m@(.*)/scripts/[^/]*$@ &&
						top_of_kernel_tree($1)) {
			$root = $1;
		}
	}

	if (!defined $root) {
		print "Must be run from the top-level dir. of a kernel tree\n";
		exit(2);
	}
}

my $emitted_corrupt = 0;

our $Ident	= qr{
			[A-Za-z_][A-Za-z\d_]*
			(?:\s*\#\#\s*[A-Za-z_][A-Za-z\d_]*)*
		}x;
our $Storage	= qr{extern|static|asmlinkage};
our $Sparse	= qr{
			__user|
			__kernel|
			__force|
			__iomem|
			__must_check|
			__init_refok|
			__kprobes|
			__ref|
			__rcu
		}x;
our $InitAttributePrefix = qr{__(?:mem|cpu|dev|net_|)};
our $InitAttributeData = qr{$InitAttributePrefix(?:initdata\b)};
our $InitAttributeConst = qr{$InitAttributePrefix(?:initconst\b)};
our $InitAttributeInit = qr{$InitAttributePrefix(?:init\b)};
our $InitAttribute = qr{$InitAttributeData|$InitAttributeConst|$InitAttributeInit};

# Notes to $Attribute:
# We need \b after 'init' otherwise 'initconst' will cause a false positive in a check
our $Attribute	= qr{
			const|
			__percpu|
			__nocast|
			__safe|
			__bitwise__|
			__packed__|
			__packed2__|
			__naked|
			__maybe_unused|
			__always_unused|
			__noreturn|
			__used|
			__cold|
			__noclone|
			__deprecated|
			__read_mostly|
			__kprobes|
			$InitAttribute|
			____cacheline_aligned|
			____cacheline_aligned_in_smp|
			____cacheline_internodealigned_in_smp|
			__weak
		  }x;
our $Modifier;
our $Inline	= qr{inline|__always_inline|noinline};
our $Member	= qr{->$Ident|\.$Ident|\[[^]]*\]};
our $Lval	= qr{$Ident(?:$Member)*};

our $Int_type	= qr{(?i)llu|ull|ll|lu|ul|l|u};
our $Binary	= qr{(?i)0b[01]+$Int_type?};
our $Hex	= qr{(?i)0x[0-9a-f]+$Int_type?};
our $Int	= qr{[0-9]+$Int_type?};
our $Float_hex	= qr{(?i)0x[0-9a-f]+p-?[0-9]+[fl]?};
our $Float_dec	= qr{(?i)(?:[0-9]+\.[0-9]*|[0-9]*\.[0-9]+)(?:e-?[0-9]+)?[fl]?};
our $Float_int	= qr{(?i)[0-9]+e-?[0-9]+[fl]?};
our $Float	= qr{$Float_hex|$Float_dec|$Float_int};
our $Constant	= qr{$Float|$Binary|$Hex|$Int};
our $Assignment	= qr{\*\=|/=|%=|\+=|-=|<<=|>>=|&=|\^=|\|=|=};
our $Compare    = qr{<=|>=|==|!=|<|>};
our $Arithmetic = qr{\+|-|\*|\/|%};
our $Operators	= qr{
			<=|>=|==|!=|
			=>|->|<<|>>|<|>|!|~|
			&&|\|\||,|\^|\+\+|--|&|\||$Arithmetic
		  }x;

our $NonptrType;
our $NonptrTypeWithAttr;
our $Type;
our $Declare;

our $NON_ASCII_UTF8	= qr{
	[\xC2-\xDF][\x80-\xBF]               # non-overlong 2-byte
	|  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
	| [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
	|  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
	|  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
	| [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
	|  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
}x;

our $UTF8	= qr{
	[\x09\x0A\x0D\x20-\x7E]              # ASCII
	| $NON_ASCII_UTF8
}x;

our $typeTypedefs = qr{(?x:
	(?:__)?(?:u|s|be|le)(?:8|16|32|64)|
	atomic_t
)};

our $logFunctions = qr{(?x:
	printk(?:_ratelimited|_once|)|
	(?:[a-z0-9]+_){1,2}(?:printk|emerg|alert|crit|err|warning|warn|notice|info|debug|dbg|vdbg|devel|cont|WARN)(?:_ratelimited|_once|)|
	WARN(?:_RATELIMIT|_ONCE|)|
	panic|
	MODULE_[A-Z_]+|
	seq_vprintf|seq_printf|seq_puts
)};

our $signature_tags = qr{(?xi:
	Signed-off-by:|
	Acked-by:|
	Tested-by:|
	Reviewed-by:|
	Reported-by:|
	Suggested-by:|
	To:|
	Cc:
)};

our @typeList = (
	qr{void},
	qr{(?:unsigned\s+)?char},
	qr{(?:unsigned\s+)?short},
	qr{(?:unsigned\s+)?int},
	qr{(?:unsigned\s+)?long},
	qr{(?:unsigned\s+)?long\s+int},
	qr{(?:unsigned\s+)?long\s+long},
	qr{(?:unsigned\s+)?long\s+long\s+int},
	qr{unsigned},
	qr{float},
	qr{double},
	qr{bool},
	qr{struct\s+$Ident},
	qr{union\s+$Ident},
	qr{enum\s+$Ident},
	qr{${Ident}_t},
	qr{${Ident}_handler},
	qr{${Ident}_handler_fn},
);
our @typeListWithAttr = (
	@typeList,
	qr{struct\s+$InitAttribute\s+$Ident},
	qr{union\s+$InitAttribute\s+$Ident},
);

our @modifierList = (
	qr{fastcall},
);

our $allowed_asm_includes = qr{(?x:
	irq|
	memory
)};
# memory.h: ARM has a custom one

sub build_types {
	my $mods = "(?x:  \n" . join("|\n  ", @modifierList) . "\n)";
	my $all = "(?x:  \n" . join("|\n  ", @typeList) . "\n)";
	my $allWithAttr = "(?x:  \n" . join("|\n  ", @typeListWithAttr) . "\n)";
	$Modifier	= qr{(?:$Attribute|$Sparse|$mods)};
	$NonptrType	= qr{
			(?:$Modifier\s+|const\s+)*
			(?:
				(?:typeof|__typeof__)\s*\([^\)]*\)|
				(?:$typeTypedefs\b)|
				(?:${all}\b)
			)
			(?:\s+$Modifier|\s+const)*
		  }x;
	$NonptrTypeWithAttr	= qr{
			(?:$Modifier\s+|const\s+)*
			(?:
				(?:typeof|__typeof__)\s*\([^\)]*\)|
				(?:$typeTypedefs\b)|
				(?:${allWithAttr}\b)
			)
			(?:\s+$Modifier|\s+const)*
		  }x;
	$Type	= qr{
			$NonptrType
			(?:(?:\s|\*|\[\])+\s*const|(?:\s|\*|\[\])+|(?:\s*\[\s*\])+)?
			(?:\s+$Inline|\s+$Modifier)*
		  }x;
	$Declare	= qr{(?:$Storage\s+)?$Type};
}
build_types();

our $Typecast	= qr{\s*(\(\s*$NonptrType\s*\)){0,1}\s*};

# Using $balanced_parens, $LvalOrFunc, or $FuncArg
# requires at least perl version v5.10.0
# Any use must be runtime checked with $^V

our $balanced_parens = qr/(\((?:[^\(\)]++|(?-1))*\))/;
our $LvalOrFunc	= qr{($Lval)\s*($balanced_parens{0,1})\s*};
our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant)};

sub deparenthesize {
	my ($string) = @_;
	return "" if (!defined($string));
	$string =~ s@^\s*\(\s*@@g;
	$string =~ s@\s*\)\s*$@@g;
	$string =~ s@\s+@ @g;
	return $string;
}

sub seed_camelcase_file {
	my ($file) = @_;

	return if (!(-f $file));

	local $/;

	open(my $include_file, '<', "$file")
	    or warn "$P: Can't read '$file' $!\n";
	my $text = <$include_file>;
	close($include_file);

	my @lines = split('\n', $text);

	foreach my $line (@lines) {
		next if ($line !~ /(?:[A-Z][a-z]|[a-z][A-Z])/);
		if ($line =~ /^[ \t]*(?:#[ \t]*define|typedef\s+$Type)\s+(\w*(?:[A-Z][a-z]|[a-z][A-Z])\w*)/) {
			$camelcase{$1} = 1;
		} elsif ($line =~ /^\s*$Declare\s+(\w*(?:[A-Z][a-z]|[a-z][A-Z])\w*)\s*[\(\[,;]/) {
			$camelcase{$1} = 1;
		} elsif ($line =~ /^\s*(?:union|struct|enum)\s+(\w*(?:[A-Z][a-z]|[a-z][A-Z])\w*)\s*[;\{]/) {
			$camelcase{$1} = 1;
		}
	}
}

my $camelcase_seeded = 0;
sub seed_camelcase_includes {
	return if ($camelcase_seeded);

	my $files;
	my $camelcase_cache = "";
	my @include_files = ();

	$camelcase_seeded = 1;

	if (-d ".git") {
		my $git_last_include_commit = `git log --no-merges --pretty=format:"%h%n" -1 -- include`;
		chomp $git_last_include_commit;
		$camelcase_cache = ".checkpatch-camelcase.git.$git_last_include_commit";
	} else {
		my $last_mod_date = 0;
		$files = `find $root/include -name "*.h"`;
		@include_files = split('\n', $files);
		foreach my $file (@include_files) {
			my $date = POSIX::strftime("%Y%m%d%H%M",
						   localtime((stat $file)[9]));
			$last_mod_date = $date if ($last_mod_date < $date);
		}
		$camelcase_cache = ".checkpatch-camelcase.date.$last_mod_date";
	}

	if ($camelcase_cache ne "" && -f $camelcase_cache) {
		open(my $camelcase_file, '<', "$camelcase_cache")
		    or warn "$P: Can't read '$camelcase_cache' $!\n";
		while (<$camelcase_file>) {
			chomp;
			$camelcase{$_} = 1;
		}
		close($camelcase_file);

		return;
	}

	if (-d ".git") {
		$files = `git ls-files "include/*.h"`;
		@include_files = split('\n', $files);
	}

	foreach my $file (@include_files) {
		seed_camelcase_file($file);
	}

	if ($camelcase_cache ne "") {
		unlink glob ".checkpatch-camelcase.*";
		open(my $camelcase_file, '>', "$camelcase_cache")
		    or warn "$P: Can't write '$camelcase_cache' $!\n";
		foreach (sort { lc($a) cmp lc($b) } keys(%camelcase)) {
			print $camelcase_file ("$_\n");
		}
		close($camelcase_file);
	}
}

$chk_signoff = 0 if ($file);

my @rawlines = ();
my @lines = ();
my @fixed = ();
my $vname;
for my $filename (@ARGV) {
	my $FILE;
	if ($file) {
		open($FILE, '-|', "diff -u /dev/null $filename") ||
			die "$P: $filename: diff failed - $!\n";
	} elsif ($filename eq '-') {
		open($FILE, '<&STDIN');
	} else {
		open($FILE, '<', "$filename") ||
			die "$P: $filename: open failed - $!\n";
	}
	if ($filename eq '-') {
		$vname = 'Your patch';
	} else {
		$vname = $filename;
	}
	while (<$FILE>) {
		chomp;
		push(@rawlines, $_);
	}
	close($FILE);
	if (!process($filename)) {
		$exit = 1;
	}
	@rawlines = ();
	@lines = ();
	@fixed = ();
}

exit($exit);

sub top_of_kernel_tree {
	my ($root) = @_;

	my @tree_check = (
		"COPYING", "CREDITS", "Kbuild", "MAINTAINERS", "Makefile",
		"README", "Documentation", "arch", "include", "drivers",
		"fs", "init", "ipc", "kernel", "lib", "scripts",
	);

	foreach my $check (@tree_check) {
		if (! -e $root . '/' . $check) {
			return 0;
		}
	}
	return 1;
}

sub parse_email {
	my ($formatted_email) = @_;

	my $name = "";
	my $address = "";
	my $comment = "";

	if ($formatted_email =~ /^(.*)<(\S+\@\S+)>(.*)$/) {
		$name = $1;
		$address = $2;
		$comment = $3 if defined $3;
	} elsif ($formatted_email =~ /^\s*<(\S+\@\S+)>(.*)$/) {
		$address = $1;
		$comment = $2 if defined $2;
	} elsif ($formatted_email =~ /(\S+\@\S+)(.*)$/) {
		$address = $1;
		$comment = $2 if defined $2;
		$formatted_email =~ s/$address.*$//;
		$name = $formatted_email;
		$name = trim($name);
		$name =~ s/^\"|\"$//g;
		# If there's a name left after stripping spaces and
		# leading quotes, and the address doesn't have both
		# leading and trailing angle brackets, the address
		# is invalid. ie:
		#   "joe smith joe@smith.com" bad
		#   "joe smith <joe@smith.com" bad
		if ($name ne "" && $address !~ /^<[^>]+>$/) {
			$name = "";
			$address = "";
			$comment = "";
		}
	}

	$name = trim($name);
	$name =~ s/^\"|\"$//g;
	$address = trim($address);
	$address =~ s/^\<|\>$//g;

	if ($name =~ /[^\w \-]/i) { ##has "must quote" chars
		$name =~ s/(?<!\\)"/\\"/g; ##escape quotes
		$name = "\"$name\"";
	}

	return ($name, $address, $comment);
}

sub format_email {
	my ($name, $address) = @_;

	my $formatted_email;

	$name = trim($name);
	$name =~ s/^\"|\"$//g;
	$address = trim($address);

	if ($name =~ /[^\w \-]/i) { ##has "must quote" chars
		$name =~ s/(?<!\\)"/\\"/g; ##escape quotes
		$name = "\"$name\"";
	}

	if ("$name" eq "") {
		$formatted_email = "$address";
	} else {
		$formatted_email = "$name <$address>";
	}

	return $formatted_email;
}

sub which_conf {
	my ($conf) = @_;

	foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
		if (-e "$path/$conf") {
			return "$path/$conf";
		}
	}

	return "";
}

sub expand_tabs {
	my ($str) = @_;

	my $res = '';
	my $n = 0;
	for my $c (split(//, $str)) {
		if ($c eq "\t") {
			$res .= ' ';
			$n++;
			for (; ($n % 8) != 0; $n++) {
				$res .= ' ';
			}
			next;
		}
		$res .= $c;
		$n++;
	}

	return $res;
}
sub copy_spacing {
	(my $res = shift) =~ tr/\t/ /c;
	return $res;
}

sub line_stats {
	my ($line) = @_;

	# Drop the diff line leader and expand tabs
	$line =~ s/^.//;
	$line = expand_tabs($line);

	# Pick the indent from the front of the line.
	my ($white) = ($line =~ /^(\s*)/);

	return (length($line), length($white));
}

my $sanitise_quote = '';

sub sanitise_line_reset {
	my ($in_comment) = @_;

	if ($in_comment) {
		$sanitise_quote = '*/';
	} else {
		$sanitise_quote = '';
	}
}
sub sanitise_line {
	my ($line) = @_;

	my $res = '';
	my $l = '';

	my $qlen = 0;
	my $off = 0;
	my $c;

	# Always copy over the diff marker.
	$res = substr($line, 0, 1);

	for ($off = 1; $off < length($line); $off++) {
		$c = substr($line, $off, 1);

		# Comments we are wacking completly including the begin
		# and end, all to $;.
		if ($sanitise_quote eq '' && substr($line, $off, 2) eq '/*') {
			$sanitise_quote = '*/';

			substr($res, $off, 2, "$;$;");
			$off++;
			next;
		}
		if ($sanitise_quote eq '*/' && substr($line, $off, 2) eq '*/') {
			$sanitise_quote = '';
			substr($res, $off, 2, "$;$;");
			$off++;
			next;
		}
		if ($sanitise_quote eq '' && substr($line, $off, 2) eq '//') {
			$sanitise_quote = '//';

			substr($res, $off, 2, $sanitise_quote);
			$off++;
			next;
		}

		# A \ in a string means ignore the next character.
		if (($sanitise_quote eq "'" || $sanitise_quote eq '"') &&
		    $c eq "\\") {
			substr($res, $off, 2, 'XX');
			$off++;
			next;
		}
		# Regular quotes.
		if ($c eq "'" || $c eq '"') {
			if ($sanitise_quote eq '') {
				$sanitise_quote = $c;

				substr($res, $off, 1, $c);
				next;
			} elsif ($sanitise_quote eq $c) {
				$sanitise_quote = '';
			}
		}

		#print "c<$c> SQ<$sanitise_quote>\n";
		if ($off != 0 && $sanitise_quote eq '*/' && $c ne "\t") {
			substr($res, $off, 1, $;);
		} elsif ($off != 0 && $sanitise_quote eq '//' && $c ne "\t") {
			substr($res, $off, 1, $;);
		} elsif ($off != 0 && $sanitise_quote && $c ne "\t") {
			substr($res, $off, 1, 'X');
		} else {
			substr($res, $off, 1, $c);
		}
	}

	if ($sanitise_quote eq '//') {
		$sanitise_quote = '';
	}

	# The pathname on a #include may be surrounded by '<' and '>'.
	if ($res =~ /^.\s*\#\s*include\s+\<(.*)\>/) {
		my $clean = 'X' x length($1);
		$res =~ s@\<.*\>@<$clean>@;

	# The whole of a #error is a string.
	} elsif ($res =~ /^.\s*\#\s*(?:error|warning)\s+(.*)\b/) {
		my $clean = 'X' x length($1);
		$res =~ s@(\#\s*(?:error|warning)\s+).*@$1$clean@;
	}

	return $res;
}

sub get_quoted_string {
	my ($line, $rawline) = @_;

	return "" if ($line !~ m/(\"[X]+\")/g);
	return substr($rawline, $-[0], $+[0] - $-[0]);
}

sub ctx_statement_block {
	my ($linenr, $remain, $off) = @_;
	my $line = $linenr - 1;
	my $blk = '';
	my $soff = $off;
	my $coff = $off - 1;
	my $coff_set = 0;

	my $loff = 0;

	my $type = '';
	my $level = 0;
	my @stack = ();
	my $p;
	my $c;
	my $len = 0;

	my $remainder;
	while (1) {
		@stack = (['', 0]) if ($#stack == -1);

		#warn "CSB: blk<$blk> remain<$remain>\n";
		# If we are about to drop off the end, pull in more
		# context.
		if ($off >= $len) {
			for (; $remain > 0; $line++) {
				last if (!defined $lines[$line]);
				next if ($lines[$line] =~ /^-/);
				$remain--;
				$loff = $len;
				$blk .= $lines[$line] . "\n";
				$len = length($blk);
				$line++;
				last;
			}
			# Bail if there is no further context.
			#warn "CSB: blk<$blk> off<$off> len<$len>\n";
			if ($off >= $len) {
				last;
			}
			if ($level == 0 && substr($blk, $off) =~ /^.\s*#\s*define/) {
				$level++;
				$type = '#';
			}
		}
		$p = $c;
		$c = substr($blk, $off, 1);
		$remainder = substr($blk, $off);

		#warn "CSB: c<$c> type<$type> level<$level> remainder<$remainder> coff_set<$coff_set>\n";

		# Handle nested #if/#else.
		if ($remainder =~ /^#\s*(?:ifndef|ifdef|if)\s/) {
			push(@stack, [ $type, $level ]);
		} elsif ($remainder =~ /^#\s*(?:else|elif)\b/) {
			($type, $level) = @{$stack[$#stack - 1]};
		} elsif ($remainder =~ /^#\s*endif\b/) {
			($type, $level) = @{pop(@stack)};
		}

		# Statement ends at the ';' or a close '}' at the
		# outermost level.
		if ($level == 0 && $c eq ';') {
			last;
		}

		# An else is really a conditional as long as its not else if
		if ($level == 0 && $coff_set == 0 &&
				(!defined($p) || $p =~ /(?:\s|\}|\+)/) &&
				$remainder =~ /^(else)(?:\s|{)/ &&
				$remainder !~ /^else\s+if\b/) {
			$coff = $off + length($1) - 1;
			$coff_set = 1;
			#warn "CSB: mark coff<$coff> soff<$soff> 1<$1>\n";
			#warn "[" . substr($blk, $soff, $coff - $soff + 1) . "]\n";
		}

		if (($type eq '' || $type eq '(') && $c eq '(') {
			$level++;
			$type = '(';
		}
		if ($type eq '(' && $c eq ')') {
			$level--;
			$type = ($level != 0)? '(' : '';

			if ($level == 0 && $coff < $soff) {
				$coff = $off;
				$coff_set = 1;
				#warn "CSB: mark coff<$coff>\n";
			}
		}
		if (($type eq '' || $type eq '{') && $c eq '{') {
			$level++;
			$type = '{';
		}
		if ($type eq '{' && $c eq '}') {
			$level--;
			$type = ($level != 0)? '{' : '';

			if ($level == 0) {
				if (substr($blk, $off + 1, 1) eq ';') {
					$off++;
				}
				last;
			}
		}
		# Preprocessor commands end at the newline unless escaped.
		if ($type eq '#' && $c eq "\n" && $p ne "\\") {
			$level--;
			$type = '';
			$off++;
			last;
		}
		$off++;
	}
	# We are truly at the end, so shuffle to the next line.
	if ($off == $len) {
		$loff = $len + 1;
		$line++;
		$remain--;
	}

	my $statement = substr($blk, $soff, $off - $soff + 1);
	my $condition = substr($blk, $soff, $coff - $soff + 1);

	#warn "STATEMENT<$statement>\n";
	#warn "CONDITION<$condition>\n";

	#print "coff<$coff> soff<$off> loff<$loff>\n";

	return ($statement, $condition,
			$line, $remain + 1, $off - $loff + 1, $level);
}

sub statement_lines {
	my ($stmt) = @_;

	# Strip the diff line prefixes and rip blank lines at start and end.
	$stmt =~ s/(^|\n)./$1/g;
	$stmt =~ s/^\s*//;
	$stmt =~ s/\s*$//;

	my @stmt_lines = ($stmt =~ /\n/g);

	return $#stmt_lines + 2;
}

sub statement_rawlines {
	my ($stmt) = @_;

	my @stmt_lines = ($stmt =~ /\n/g);

	return $#stmt_lines + 2;
}

sub statement_block_size {
	my ($stmt) = @_;

	$stmt =~ s/(^|\n)./$1/g;
	$stmt =~ s/^\s*{//;
	$stmt =~ s/}\s*$//;
	$stmt =~ s/^\s*//;
	$stmt =~ s/\s*$//;

	my @stmt_lines = ($stmt =~ /\n/g);
	my @stmt_statements = ($stmt =~ /;/g);

	my $stmt_lines = $#stmt_lines + 2;
	my $stmt_statements = $#stmt_statements + 1;

	if ($stmt_lines > $stmt_statements) {
		return $stmt_lines;
	} else {
		return $stmt_statements;
	}
}

sub ctx_statement_full {
	my ($linenr, $remain, $off) = @_;
	my ($statement, $condition, $level);

	my (@chunks);

	# Grab the first conditional/block pair.
	($statement, $condition, $linenr, $remain, $off, $level) =
				ctx_statement_block($linenr, $remain, $off);
	#print "F: c<$condition> s<$statement> remain<$remain>\n";
	push(@chunks, [ $condition, $statement ]);
	if (!($remain > 0 && $condition =~ /^\s*(?:\n[+-])?\s*(?:if|else|do)\b/s)) {
		return ($level, $linenr, @chunks);
	}

	# Pull in the following conditional/block pairs and see if they
	# could continue the statement.
	for (;;) {
		($statement, $condition, $linenr, $remain, $off, $level) =
				ctx_statement_block($linenr, $remain, $off);
		#print "C: c<$condition> s<$statement> remain<$remain>\n";
		last if (!($remain > 0 && $condition =~ /^(?:\s*\n[+-])*\s*(?:else|do)\b/s));
		#print "C: push\n";
		push(@chunks, [ $condition, $statement ]);
	}

	return ($level, $linenr, @chunks);
}