# ATOM(BOX) FIELD CHANGE
# Usage: ruby atomChange.rb infile outfile
# Ver: 1.0.2
# Hist:
#     2007/11/13・・・構築
#     2007/11/14・・・高速化
#     2007/11/15・・・fsearchのデバッグ
#     2009/09/26・・・一行入魂様よりご指摘いただいたFILE SEARCH関数の修正
#                     http://aoyagikouhei.blog8.fc2.com/blog-entry-64.html
#

#-------------------------------------------------------------------------------------------
# VARS
IN_FILE = ARGV[0]
OUT_FILE = ARGV[1]

UUID = "%A8%8C%11%D4%81%97%00%90%27%08%77%03"
item0= "ftypkddi%00%00%01%00kddi3g2a"
item1= "uuidcpgd" + UUID + "%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00%00"
item2= "uuidenci" + UUID + "%00%00%00%00KDDI-SA%00W21SA%00%00%00SAMP4v2%00SAMUXv2%00"
item3= "uuidmvml" + UUID + "%00%00%00%00%FF%FF%E0%00"   # <- TIMESTAMP ADD AFTER

#-------------------------------------------------------------------------------------------
# FUNCTION

	# CODE 2 ASCII
	def code2ascii(str)
		if /%{1}/ =~ str
			conv_str = ""
			codes = str.split('%')
			codes.each{|code|
				if /^([0-9A-F]){2}$/ =~ code
					code = [code].pack("H*")
				elsif /^([0-9A-F]){2}.+/ =~ code
					code_body = [code.slice(0,2)].pack("H*")
					str_body = code.slice(2,code.length - 2)
					code = code_body + str_body
				end
				conv_str += code
			}
			return conv_str
		else
			return str
		end
	end
	
	# GET DATA VALUE
	def getDWORD(vword)
		vword = vword.unpack("H*")
		data_value = vword.to_s.hex
		return data_value.to_i
	end
	
	# FILE SEARCH
	def fsearch(file,word)
		pos = []
		word.length.times {|start_pos|
			begin
				i_stream = open(file, "rb")
			rescue => ex
				print ex.message, "\n"
				exit
			end
			readed = 0
			if start_pos > 0
				i_stream.read(start_pos)
				readed = start_pos
			end
			while data = i_stream.read(1024)
				data = data.to_s
				index = data.index(word)
				while nil != index
					pos << readed + index
					index = data.index(word, index + 1)
				end
				readed += data.length
			end
			i_stream.close
		}
		if pos.length > 0
			pos = pos.uniq
			pos = pos.sort{|a,b| a<=>b}
			return pos
		else
			return false
		end
	end
	
#-------------------------------------------------------------------------------------------
# MAIN
	# CHECK FILE NAME
	if IN_FILE == OUT_FILE
		print "Can't replace file"
		exit
	end
	
	# TIMESTAMP
	begin
		t = File::mtime(IN_FILE)
		creationTime = t.to_i + 0x7C25B080
	rescue => ex
		print ex.message, "\n"
		exit
	end
	
	ts_s  = ""
	ts_s += "%" + format("%02x",(creationTime / 0x1000000) & 0xFF).upcase
	ts_s += "%" + format("%02x",(creationTime / 0x10000) & 0xFF).upcase
	ts_s += "%" + format("%02x",(creationTime / 0x100) & 0xFF).upcase
	ts_s += "%" + format("%02x",(creationTime) & 0xFF).upcase
	
	# item3 ADD TIMESTAMP
	item3 += ts_s
	
	# CREATE ftyp + uuid
	item0_cnv = code2ascii(item0)
	item1_cnv = code2ascii(item1)
	item2_cnv = code2ascii(item2)
	item3_cnv = code2ascii(item3)
	fu_box  = ""
	fu_box += [format("%08x",item0_cnv.length + 4)].pack("H*")
	fu_box += item0_cnv
	fu_box += [format("%08x",item1_cnv.length + 4)].pack("H*")
	fu_box += item1_cnv
	fu_box += [format("%08x",item2_cnv.length + 4)].pack("H*")
	fu_box += item2_cnv
	fu_box += [format("%08x",item3_cnv.length + 4)].pack("H*")
	fu_box += item3_cnv
	
	# OUTPUT FILE CREATE
	begin
		o_stream = open(OUT_FILE, "wb")
		o_stream.print ""
		o_stream.close
	rescue => ex
		print ex.message, "\n"
		exit
	end
	
	# stco POSITION
	stco_pos = fsearch(IN_FILE,"stco")
	
	# ATOM CHANGE
	begin
		# INPUT & OUTPUT FILE OPEN
		i_stream = open(IN_FILE, "rb")
		o_stream = open(OUT_FILE, "ab")
	
		# READED BITE
		readed = 0
		
		# WRITED BITE
		writed = 0
		
		# ftyp & uuid WRITE
		o_stream.print fu_box
		writed = fu_box.length
		ftyp_length = getDWORD(i_stream.read(4))
		i_stream.read(ftyp_length - 4)
		readed = ftyp_length
		diff = writed - readed
		
		# stco WRITE
		stco_pos.each {|spos|
			# WRITE BEFORE DATA
			before_data_length = spos - 4 - readed
			readed += before_data_length
			writed += before_data_length
			while before_data_length > 0
				if(before_data_length > 1024)
					read_length = 1024
					before_data_length -= 1024
				else
					read_length = before_data_length
					before_data_length = 0
				end
				o_stream.print i_stream.read(read_length)
			end
			
			# stco DATA LENGTH
			stco_length = i_stream.read(4)
			readed += 4
			o_stream.print stco_length
			writed += 4
			stco_length = getDWORD(stco_length) - 16		# "16" is STATIC AREA LENGTH
			
			# WRITE stco STATIC AREA
			stco_static_area = i_stream.read(12)
			readed += 12
			o_stream.print stco_static_area
			writed += 12
			
			# UPDATE stco
			while stco_length > 0
				dpos = i_stream.read(4)
				readed += 4
				stco_length -= 4
				o_stream.print [format("%08x",getDWORD(dpos) + diff)].pack("H*")
				writed += 4
			end
		}
	
		# LEAST DATA WRITE
		while data = i_stream.read(1024)
			o_stream.print data
			readed += data.length
			writed += data.length
		end
		
		# STREAM CLOSE
		o_stream.close
		i_stream.close
		
	rescue => ex
		print ex.message, "\n"
		exit
	end