#!/usr/bin/perl -w  
 
# Check @ARGV  
if(@ARGV != 1) { 
	print "[!] Usage: perl script.pl <file.c>\n"; 
	exit(-1); 
} 
 
# Open files 
open(OLDFILE, "<$ARGV[0]") || die "[!] Cannot open $ARGV[0]!\n";  
open(NEWFILE, ">new_$ARGV[0]") || die "[!] Cannot open new_$ARGV[0]!\n";  
 
# Read file content 
@lines = <OLDFILE>; 
print "$ARGV[0]\n\n"; 
   
# Parse each line 
for($i=0; $i < @lines; $i++) { 
	if($lines[$i] =~ m/(\w+)\s+<<=\s+(\w+)/) { 
 
		($var1, $var2) = ($1, $2); 
		print "[+] line ". ($i + 1) .": Found var1=$var1 and var2=$var2\n"; 
 
		$type1 = findType($var1, $i); 
		if(!$type1) { 
			print "[+] line ". ($i + 1) .": Type for $var1 not found!\n\n"; 
			exit(-1); 
		} 
		else { 
			print "[+] line ". ($i + 1) .": Type found: $type1\n\n"; 
		} 
 
		$lines[$i] =~ s/$var1\s+<<=\s+$var2\s*;/$var1 = ($type1)((unsigned $type1)$var1 << $var2);/g;  
	} 
	 
	print NEWFILE $lines[$i];   
}   
          
# Close files 
close(OLDFILE);  
close(NEWFILE);  
 
exit(0); 
 
 
 
# This function try to find the declaration reading the lines before.  
sub findType 
{ 
	my $var = shift; 
	my $i = shift; 
 
	for(; $i >= 0; $i--) { 
		return $1 if ($lines[$i] =~ m/(char|int|long|float|double)\s+$var[^\(]/);  
	} 
 
	return undef; 
}

m/(char|int|long|float|double)\s+$var[^\(]/