#! /usr/bin/perl

# ----------------------------------------------------------------
# John Kerl
# kerl.john.r@gmail.com
# 2002/12/01
#
# Does a global search and replace for a pattern in specified files.
# Useful for heavy-duty reworking of source code.
#
# Example:
#   krepl grody_function_name better_function_name */*.[ch]
# ----------------------------------------------------------------

$word_match = 0;
if (@ARGV) {
	if ($ARGV[0] eq "-w") {
		$word_match = 1;
		shift @ARGV;
	}
}

if (@ARGV < 3) {
	die "Usage: $0 {old pattern} {new pattern} {file names ... }\n";
}

$oldpat = $ARGV[0];
$newpat = $ARGV[1];

shift @ARGV;
shift @ARGV;

$nfiles = @ARGV;

foreach $filename (@ARGV) {
	next if -d $filename;

	if ($nfiles > 1) {
		print ".";
	}

	$tempname = $filename . ".repl";

	if (!open(FILEHANDLE, $filename)) {
		print "Couldn't open file \"$filename\"; skipping.\n";
		next;
	}

	$mode = (stat($filename))[2] & 07777;

	if (!open(TEMPHANDLE, ">$tempname")) {
		print "Couldn't open file \"$tempname\"; skipping.\n";
		close FILEHANDLE;
		next;
	}

	while ($line = <FILEHANDLE>) {
		if ($word_match) {
			$line =~ s/\b$oldpat\b/$newpat/g;
		}
		else {
			$line =~ s/$oldpat/$newpat/g;
		}
		print TEMPHANDLE $line;
	}

	close FILEHANDLE;
	close TEMPHANDLE;

	chmod $mode, $tempname;

	if (!rename($tempname, $filename)) {
		warn "Cannot rename $tempname to $filename: $!\n";
	}
}
print "\n";