--==[[############################################################]]==--
--==[[ Function Name: IsHeader;                                   ]]==--
--==[[ Function Desc: Checks if a certain file contains a header  ]]==--
--==[[ 				  using the given table of bytes. even null   ]]==--
--==[[ 				  character is supported!                     ]]==--
--==[[ Author:		  Imagine Programming                         ]]==--
--==[[ Website:		  http://www.imagine-programming.com          ]]==--
--==[[                                                            ]]==--
--==[[ Returns -1    if byte table is corrupt (numbers between 0  ]]==--
--==[[ 		         and 255 required..                           ]]==--
--==[[ Returns -2    if file couldn't be read.                    ]]==--
--==[[ Returns -3    if byte table has no entries.                ]]==--
--==[[ Returns true  if header was found.                         ]]==--
--==[[ Returns false if header was not found.                     ]]==--
--==[[############################################################]]==--
function IsHeader(sFile, tBytes)
	local sBytes;
	if(tBytes)then
		sBytes = "";
		for i, v in pairs(tBytes) do
			if(type(v=="number"))and(v<256)and(v>-1)then
				sBytes=sBytes..string.char(v);
			else
				return -1;
			end
		end
		local f = io.open(sFile, "rb");
		if(f)then
			local nBytesLength = string.len(sBytes);
			if(nBytesLength~=0)then
				local c = f:read(nBytesLength);
				f:close();
				if(c==sBytes)then 
					return true;
				else 
					return false;
				end
			else
				f:close();
				return -3;
			end
		else
			return -2;
		end
	end
end