Class: FastLib

Inherits:
Object
  • Object
show all
Defined in:
lib/fastlib.rb

Overview

The FastLib class implements the meat of the FASTLIB archive format

Constant Summary collapse

VERSION = 
"0.0.7"
FLAG_COMPRESS = 
0x01
FLAG_ENCRYPT = 
0x02
@@cache = 
{}
@@has_zlib = 
false

Class Method Summary collapse

Class Method Details

.cache ⇒ Object

Expose the cache to callers



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# File 'lib/fastlib.rb', line 274

def self.cache
	@@cache
end

.decrypt_00000000(data) ⇒ Object 



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# File 'lib/fastlib.rb', line 267

def self.decrypt_00000000(data)
	encrypt_00000000(data)
end

.decrypt_12345600(data) ⇒ Object 



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# File 'lib/fastlib.rb', line 259

def self.decrypt_12345600(data)
	encrypt_00000000(data)
end

.dump(lib, flag, bdir, *dirs) ⇒ Object

This method provides a way to create a FASTLIB archive programatically, the key arguments are the name of the destination archive, the base directory that should be excluded from the archived path, and finally the list of specific files and directories to include in the archive.



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# File 'lib/fastlib.rb', line 190

def self.dump(lib, flag, bdir, *dirs)
	head = ""
	data = ""
	hidx = 0
	didx = 0
	
	bdir = bdir.gsub(/\/$/, '')
	brex = /^#{Regexp.escape(bdir)}\//
	
	@@cache[lib] = {
		:fastlib_flags => flag.to_i(16)
	}
	
	dirs.each do |dir|
		::Find.find(dir).each do |path|
			next if not ::File.file?(path)
			name = fastlib_filter_encode( lib, path.sub( brex, "" ) )
			
			buff = ""
			::File.open(path, "rb") do |fd|
				buff = fastlib_filter_encode(lib, fd.read(fd.stat.size))
			end
			

			head << [ name.length, didx, buff.length, ::File.stat(path).mtime.utc.to_i ].pack("NNNN")
			head << name
			hidx = hidx + 16 + name.length
		
			data << buff
			didx = didx + buff.length
		end
	end
	
	head << [0,0,0].pack("NNN")
	
	::File.open(lib, "wb") do |fd|
		fd.write("FAST")
		fd.write( [ head.length, flag.to_i(16) ].pack("NN") )
		fd.write( head )
		fd.write( data )
	end	
end

.encrypt_00000000(data) ⇒ Object 



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# File 'lib/fastlib.rb', line 263

def self.encrypt_00000000(data)
	data.unpack("C*").map{ |c| c ^ 0x90 }.pack("C*")
end

.encrypt_12345600(data) ⇒ Object

This is a stub crypto handler that performs a basic XOR operation against a fixed one byte key. The two usable IDs are 12345600 and 00000000



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# File 'lib/fastlib.rb', line 255

def self.encrypt_12345600(data)
	encrypt_00000000(data)
end

.fastlib_filter_decode(lib, buff) ⇒ Object

This method provides compression and encryption capabilities for the fastlib archive format.



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# File 'lib/fastlib.rb', line 127

def self.fastlib_filter_decode(lib, buff)

	if (@@cache[lib][:fastlib_flags] & FLAG_ENCRYPT) != 0
	
		@@cache[lib][:fastlib_decrypt] ||= ::Proc.new do |data|
			stub = "decrypt_%.8x" % ( @@cache[lib][:fastlib_flags] & 0xfffffff0 )
			FastLib.send(stub, data)
		end

		buff = @@cache[lib][:fastlib_decrypt].call( buff )
	end
	
	if (@@cache[lib][:fastlib_flags] & FLAG_COMPRESS) != 0
		if not @@has_zlib
			raise ::RuntimeError, "zlib is required to open this archive"
		end

		z = Zlib::Inflate.new
		buff = z.inflate(buff)
		buff << z.finish
		z.close	
	end
	
	buff
end

.fastlib_filter_encode(lib, buff) ⇒ Object

This method provides compression and encryption capabilities for the fastlib archive format.



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# File 'lib/fastlib.rb', line 157

def self.fastlib_filter_encode(lib, buff)
	
	if (@@cache[lib][:fastlib_flags] & FLAG_COMPRESS) != 0
		if not @@has_zlib
			raise ::RuntimeError, "zlib is required to open this archive"
		end

		z = Zlib::Deflate.new
		buff = z.deflate(buff)
		buff << z.finish
		z.close	
	end

	if (@@cache[lib][:fastlib_flags] & FLAG_ENCRYPT) != 0
	
		@@cache[lib][:fastlib_encrypt] ||= ::Proc.new do |data|
			stub = "encrypt_%.8x" % ( @@cache[lib][:fastlib_flags] & 0xfffffff0 )
			FastLib.send(stub, data)
		end

		buff = @@cache[lib][:fastlib_encrypt].call( buff )
	end
	
	buff
end

.list(lib) ⇒ Object

This archive provides a way to list the contents of an archive file, returning the names only in sorted order.



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# File 'lib/fastlib.rb', line 237

def self.list(lib)
	load_cache(lib)
	( @@cache[lib] || {} ).keys.map{|x| x.to_s }.sort.select{ |x| @@cache[lib][x] }
end

.load(lib, name, noprocess = false) ⇒ Object

This method loads content from a specific archive file by name. If the noprocess argument is set to true, the contents will not be expanded to include workarounds for things such as __FILE__. This is useful when loading raw binary data where these strings may occur



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# File 'lib/fastlib.rb', line 70

def self.load(lib, name, noprocess=false)
	data = ""
	load_cache(lib)

	return if not ( @@cache[lib] and @@cache[lib][name] )
	
	
	::File.open(lib, "rb") do |fd|
		fd.seek(
			@@cache[lib][:fastlib_header][0] +
			@@cache[lib][:fastlib_header][1] + 
			@@cache[lib][name][0]
		)
		data = fastlib_filter_decode( lib, fd.read(@@cache[lib][name][1] ))
	end
	
	# Return the contents in raw or processed form
	noprocess ? data : post_process(lib, name, data)
end

.load_cache(lib) ⇒ Object

This method caches the file list and offsets within the archive



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# File 'lib/fastlib.rb', line 93

def self.load_cache(lib)
	return if @@cache[lib]
	@@cache[lib] = {}
	
	return if not ::File.exists?(lib)
			
	::File.open(lib, 'rb') do |fd|
		dict = {}
		head = fd.read(4)
		return if head != "FAST"
		hlen = fd.read(4).unpack("N")[0]
		flag = fd.read(4).unpack("N")[0]			
	
		@@cache[lib][:fastlib_header] = [12, hlen, fd.stat.mtime.utc.to_i ]
		@@cache[lib][:fastlib_flags]  = flag
		
		nlen, doff, dlen, tims = fd.read(16).unpack("N*")
		
		while nlen > 0
			name = fastlib_filter_decode( lib, fd.read(nlen) )
			dict[name] = [doff, dlen, tims]
			
			nlen, doff, dlen, tims = fd.read(16).unpack("N*")
		end
		
		@@cache[lib].merge!(dict)
	end
	
end

.post_process(lib, name, data) ⇒ Object

This method is called on the loaded is required to expand __FILE__ and other inline dynamic constants to map to the correct location.



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# File 'lib/fastlib.rb', line 246

def self.post_process(lib, name, data)
	data.gsub('__FILE__', "'#{ ::File.expand_path(::File.join(::File.dirname(lib), name)) }'")
end

.version ⇒ Object

This method returns the version of the fastlib library



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# File 'lib/fastlib.rb', line 60

def self.version
	VERSION
end