#!/usr/bin/perl

#
# IndexListing.pl -- Chris B. Sears
#
# December 19, 1999
#
# The Linux Core Kernel Commentary didn't have an index.
# This script takes the listing file and the source tree
# and using commonly found household text editing utitilies
# constructs a thorough cross reference.
#
# The result is index.pdf
#
# This script uses:
#	Exhuberant CTags:
#		rpmfind.net/linux/RPM/ctags.html
#	GNU enscript
#	GhostScript ps2pdf
#

$max_references = 10;

%file_offsets = ();
$offset = 0;

use Text::Wrap;
$Text::Wrap::columns = 50;

sub index_file {
	open (INDEX_OUT, ">" . $_[0]);
	open (INDEX_IN, "index_data");
	$entry = "";

	while ($line = <INDEX_IN>) {
		$output = "";
		@words = split(" ", $line);

		#
		#skip over gcc cruft
		#
		if (($words[0] eq "__initfunc") || ($words[0] eq "EXPORT_SYMBOL")) {
			next;
		}

		#
		# skip duplicate names
		#
		if ($words[0] eq $entry) {
			next;
		}
		$entry = $words[0];

		#
		# merge multiple definition and prototype line numbers.
		# for functions and prototypes use two passes
		# sort functions before prototypes
		#
		$count = 0;
		@defs = ();
		if ($_[0] eq "index_f") {
			open (INDEX_COPY, "index_data");
			while ($line = <INDEX_COPY>) {
				@copies_words = split(" ", $line);
				if (($copies_words[0] eq $entry) &&
					($copies_words[1] eq "function")) {
					$defs[$count] =
						($file_offsets{$copies_words[3]} + $copies_words[2]);
					$count++;
				}
			}
			close (INDEX_COPY);
			open (INDEX_COPY, "index_data");
			while ($line = <INDEX_COPY>) {
				@copies_words = split(" ", $line);
				if (($copies_words[0] eq $entry) &&
					($copies_words[1] eq "prototype")) {
					$defs[$count] =
						($file_offsets{$copies_words[3]} + $copies_words[2]);
					$count++;
				}
			}
			close (INDEX_COPY);
		} else {
			open (INDEX_COPY, "index_data");
			while ($line = <INDEX_COPY>) {
				@copies_words = split(" ", $line);
				if ($copies_words[0] eq $entry) {
					$defs[$count] =
						($file_offsets{$copies_words[3]} + $copies_words[2]);
					$count++;
				}
			}
			close (INDEX_COPY);
		}

		#
		# Find references to the names
		#
		$output = $output . $words[0] . " -";
		for ($i = 0; $i < $count; $i++) {
			$output = $output . " " . $defs[$i];
		}
		$output = $output . " -";

		system("grep -n " .
			"'\\<" . $words[0] .  "\\>'" .
			" arch/*/*/* fs/* include/*/* init/*" .
			" ipc/* kernel/* mm/* >index_tmp");

		open (INDEX_TMP, "index_tmp");
		$total = 0;
		OUTER: while ($line = <INDEX_TMP>) {
			@match_words = split(":", $line);
			$offset = ($file_offsets{$match_words[0]} + $match_words[1]);

			#
			# but filter out the definitions
			#
			for ($i = 0; $i < $count; $i++) {
				if ($defs[$i] == $offset) {
					next OUTER;
				}
			}

			#
			# and limit the total number of references
			#
			$total++;
			if ($total <= $max_references) {
				$output = $output . " " . $offset;
			}
		}
		if ($total > $max_references) {
			$output = $output . sprintf " [+%d]", $total - $max_references;
		}

		close (INDEX_TMP);
		system("rm -f index_tmp");

		if (substr($output, -2, 2) eq " -") {
			chop $output;
			chop $output;
		}

		@output_line = ($output);

		print INDEX_OUT wrap("", "    ", @output_line), "\n";
	}
	close (INDEX_OUT);
	close (INDEX_IN);

	system("enscript -r " . $_[0] . " --columns=3 -o " . $_[0] .
		".ps -j -b \"Linux Core Kernel Commentary -- " . $_[1] .
		"\" -f Courier8 -F Helvetica10");
	system("rm -f index_data " . $_[0]);
}

#
# scan lckc_code for FILE:
# create a list of names and offsets
#
open (LISTING, "lckc_code");
while ($line = <LISTING>) {
	if ($line =~ / FILE:/) {
		@words = split(" ", $line);
		$file_offsets{$words[2]} = $offset;
	} else {
		$offset++;
	}
}
close (LISTING);

system("ctags -xR --c-types=fp" .
	" arch fs include init ipc kernel mm >index_data");
system("sort -df index_data >sort_tmp; mv sort_tmp index_data");
index_file("index_f", "Functions");

system("ctags -xR --c-types=dvegstu" .
	" arch fs include init ipc kernel mm | grep -v \"undef\" >index_data");
system("sort -df index_data >sort_tmp; mv sort_tmp index_data");
index_file("index_d",
	"Macros, Variables, Enumerations, Structures, Typedefs and Unions");

system("cat index_f.ps index_d.ps >index.ps");
system("ps2pdf index.ps");
system("rm -f index.ps index_f.ps index_d.ps");